JP2014196196A - Transport mechanism and image formation device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transport mechanism which enables a transport roller to be easily attached and detached and improves the attachment stability of the transport roller, and to provide an image formation device including the transport mechanism.SOLUTION: A paper feeding mechanism 500 includes: a paper feeding roller assembly 330 including a paper feeding roller 335 that transports a sheet, a roller support section 310 which may expand and retract in an axial direction, and a first flange part 337 operated when the roller support section 310 is retracted in a direction that a second end part 334 is moved close to a first end part 333; a bearing 341 which rotatably and detachably supports the first end part 333 of the roller support section 310; a connection section 342 to which the second end part 334 of the roller support section 310 is detachably connected; and a pin 345 which supports the bearing 341 so that the bearing 341 swings between a first position where the bearing 341 faces the connection section 342 and a second position where the bearing 341 does not face the connection section 342.

Description

  The present invention relates to a conveyance mechanism for conveying a sheet and an image forming apparatus including the conveyance mechanism.

  Conventionally, in maintenance of image forming apparatuses such as copiers, printers, facsimiles, or multi-function peripherals (MFPs) having these functions, a serviceman has conventionally provided parts such as paper feed rollers and separation pads according to the service contract system of these apparatuses. It was generally done to replace. Therefore, there are few image forming apparatuses designed so that the user can easily replace parts by himself.

  However, recently, a mechanism design (CRU design: Customers) that makes it easy to set up and reduce the time required for repairs by service personnel, or allows the user to easily replace the life parts without having to visit the service personnel one by one. Various Replacing Units have been proposed.

  For example, Patent Document 1 proposes a technique for reducing the axial structure and the radial play in the sheet material conveying apparatus, thereby improving the assembly and improving the structure of the apparatus by improving the spring structure. . In this configuration of the sheet material conveying device, a groove having an axial pressing surface and a radial pressing surface is formed at least one of the bearings of the paper feeding roller or the end of the paper feeding roller. The wire spring that is simultaneously energized is locked to the fixing portion of the apparatus main body.

  Japanese Patent Application Laid-Open No. H11-228688 proposes a technique for easily exchanging an ink cassette even in a narrow place in a thermal transfer printer. In the configuration of this thermal transfer type printer device, a front lid portion that can be freely opened and closed on the front side surface of the main body, and one bobbin side end of the ink cassette are held, and the printer can be rotated in the vertical direction while holding the ink cassette. A first holding portion having a rotation shaft provided on both side surfaces; and a second holding portion for holding the other bobbin side end of the ink cassette after rotating the first holding portion.

JP-A-8-225182 Japanese Patent Laid-Open No. 2002-19208

  However, the apparatuses described in Patent Documents 1 and 2 also have a problem in that the user cannot easily attach and detach components such as the paper feed roller because the mechanism for holding the components is complicated.

  In addition, in order to facilitate the removal of the paper feed roller, the roller shaft fixed coaxially to the paper feed roller is made extendable in the axial direction, and the roller shaft is connected to the bearing on the apparatus main body side and the tip of the drive shaft. There has been proposed a structure that can be easily connected to a portion (see FIG. 14). In this structure, when removing the paper feed roller, the roller shaft is contracted, and both end portions of the roller shaft are separated from the bearing portion and the connecting portion along the axial direction, and then the paper feed roller is pulled out to the apparatus main body. Can do.

  However, in this structure, when removing the paper feed roller, it is necessary to keep both ends of the roller shaft away from the bearing and the connecting portion along the axial direction, so positioning of the roller shaft is difficult. There is a problem that is very difficult for those who are not used to.

  In addition, considering that the paper feed roller can be easily removed, the axial length (width) of the part where the roller shaft end and the bearing fit together cannot be extended. There is a problem that it is difficult to improve the performance.

  The present invention has been made in order to solve the above-described problem, and includes a transport mechanism that can easily attach and detach the transport roller and can improve the mounting stability of the transport roller, and the transport mechanism. Another object of the present invention is to provide an image forming apparatus.

The transport mechanism of the present invention includes a base, a transport roller that transports a sheet, and is coaxially fixed to the transport roller and is extendable in the axial direction, and has a first end and a second end at both ends in the axial direction. A roller support portion , and a conveying roller assembly having a first collar portion operated when the roller support portion is contracted in a direction to bring the second end portion closer to the first end portion; and the roller support portion provided on the base portion. A bearing that rotatably and detachably supports the first end portion of the portion, and a connecting portion that is disposed to face the bearing at the base portion and is detachably connected to the second end portion of the roller support portion When, the bearing, characterized in that it and a pivot shaft supporting so that it can pivot between a second position not facing the first position and the connecting portion opposite to the connecting portion (claims Item 1).

According to the above configuration, in the state where the transport roller assembly is attached to the base, the first end and the second end at both ends in the axial direction of the roller support are respectively supported by the bearing and the connecting portion of the base. . When removing the conveying roller from this state , the roller support portion is contracted by moving the first collar portion by hand to separate the second end portion from the connecting portion, and then the first end portion of the roller support portion is the bearing. The conveying roller assembly and the bearing are swung around the swivel axis while being supported by the shaft. Accordingly, it is not necessary to separate both ends of the roller support portion from the bearing and the connection portion, and the transport roller assembly can be easily removed in the order of the connection portion and the bearing.

  In addition, since it is not necessary to separate the both ends of the roller support portion from the bearing and the connecting portion at the same time, the axial length of the portion where the first end portion of the roller support portion and the bearing are fitted can be extended. Thus, it is possible to improve the mounting stability of the transport roller assembly.

  The roller support portion includes a first shaft portion and a second shaft portion that slide relative to each other, the first collar portion is provided on the first shaft portion, and the transport roller assembly includes the second shaft portion. It is preferable that the apparatus further includes a second collar portion provided on the shaft portion, and the first collar portion and the second collar portion are arranged with the conveying roller interposed therebetween (Claim 2).

  According to such a configuration, the roller support portion can be contracted simply by grasping the first collar portion and the second collar portion by hand.

It is preferable to further include a biasing member that biases the bearing from the first position toward the second position.

According to whether a configuration, bearings, by the urging member, because it is biased toward the first position to the second position, the second end of the roller support portion from the connecting portion shortens the roller support portion if brought into disengaged, by the urging force of the urging member, Ru can der possible to easily turn the bearing and the conveying roller assembly from the first position to the second position.

It said biasing member, when the bearing is in the second position, it is preferable to hold the bearing to the second position (claim 4).

  According to such a configuration, when the bearing capable of pivoting around the pivot axis is held at the second position by the biasing member when in the second position, the bearing is more external than when in the first position. It is easy to see from and is easily connected. Therefore, when attaching the conveyance roller assembly, the first end portion of the roller support portion can be easily connected to the bearing.

A positioning member that contacts the bearing and positions the bearing at the first position is further provided, and the biasing member is interposed between the bearing and the positioning member, so that the bearing is moved to the first position. It is preferable to hold in two positions (Claim 5 ).

  According to this configuration, the biasing member is interposed between the bearing and the positioning member, so that the bearing can be separated from the positioning member by an angular range in which the biasing member is interposed. Therefore, the bearing can be accurately held at the second position by using the biasing member and the positioning member.

The urging member is preferably made of a plate-like elastic body (Claim 6).

  According to this configuration, since the urging member is made of a plate-like elastic body, the bearing can be accurately held at the second position by the elastic force of the plate-like elastic body. Further, when the transport roller assembly is attached, it is possible to easily return the bearing to the first position while bending the plate-like elastic body. Further, when the bearing is in the first position, the plate-like elastic body is flattened, so that the space occupied by the plate-like elastic body is reduced. Moreover, since the plate-like elastic body has a simple shape, it is easy to remove the mold at the time of resin molding, so that it can be easily integrally molded with the synthetic resin together with the bearing.

The image forming apparatus according to the present invention is characterized by comprising the above conveying mechanism, and an image forming unit for forming an image on the sheet conveyed by the conveying mechanism (claim 7).

  According to this configuration, since the image forming apparatus includes the above-described transport mechanism, the transport roller assembly can be easily attached and detached by rotating the bearing around the swing axis. In addition, the axial length of the portion where the first end of the roller support portion and the bearing are fitted can be extended, and the mounting stability of the transport roller assembly can be improved.

  As described above, according to the present invention, the transport roller can be easily attached and detached. At the same time, it is possible to improve the mounting stability of the transport roller.

1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an internal configuration of the image forming apparatus illustrated in FIG. 1. FIG. 2 is a perspective view of a sheet feeding mechanism in a state incorporated in the image forming apparatus illustrated in FIG. 1. FIG. 4 is a perspective view illustrating a state where a sheet feeding roller assembly is removed from the sheet feeding mechanism illustrated in FIG. 3. FIG. 4 is a perspective view of the paper feed mechanism shown in FIG. 3. FIG. 4 is a plan view of the paper feed mechanism shown in FIG. 3. FIG. 6 is a cross-sectional view of the paper feed roller assembly shown in FIG. 5. It is a perspective view which shows the bearing shown by FIG. 5, the positioning member of the periphery, and a leaf | plate spring. It is a side view of the bearing, positioning member, and leaf | plate spring which are shown by FIG. FIG. 6 is a front view showing a state in the middle of removal of a paper feed roller assembly in the paper feed mechanism shown in FIG. 5. FIG. 6 is a perspective view showing a state in the middle of removal of a paper feed roller assembly in the paper feed mechanism shown in FIG. 5. FIG. 6 is a front view illustrating a state where a sheet feeding roller assembly in the sheet feeding mechanism illustrated in FIG. 5 is turned and removed. FIG. 6 is a perspective view illustrating a state in which a sheet feeding roller assembly in the sheet feeding mechanism illustrated in FIG. 5 is turned and removed. FIG. 6 is a plan view showing a state in the middle of removal of a paper feed roller assembly in a conventional paper feed mechanism as a comparative example of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that terms used in the following description, such as “up”, “down”, “left”, “right” and the like, are merely for the purpose of clarifying the explanation and do not limit the present invention. Not what you want. In the following description, the term “sheet” is subjected to an image forming process such as copy paper, coated paper, an OHP sheet, cardboard, a postcard, and tracing paper, and an optional process other than the image forming process. Includes other sheet materials. The “sheet feeding mechanism” shown in the following description is used to convey a “sheet” subjected to an image forming process. However, in another specific embodiment, an arbitrary process other than the image forming process ( For example, it may be used in a transport mechanism for transporting a sheet subjected to perforation processing, bending processing, and cutting processing. The terms “upstream”, “downstream” and similar terms used in the following description mean “upstream”, “downstream” and similar concepts in the sheet conveyance direction.

  FIG. 1 is a perspective view of an image forming apparatus 1 in which a paper feed mechanism 500 is incorporated. FIG. 2 schematically shows the internal structure of the image forming apparatus shown in FIG. The image forming apparatus shown in FIGS. 1 and 2 is a so-called in-body discharge type copying machine, but the present invention is not limited to this, and a printer, a facsimile machine, and a multifunction machine having these functions. Or another apparatus for forming a toner image on a sheet.

  The image forming apparatus 1 includes a housing 2 having a substantially rectangular parallelepiped shape. The casing 2 includes a substantially rectangular parallelepiped lower casing 21, a substantially rectangular parallelepiped upper casing 22 disposed above the lower casing 21, and a connection that connects the lower casing 21 and the upper casing 22. And a housing 23. The connection housing 23 extends along the right edge and the back edge of the housing 2. The sheet subjected to the printing process is discharged into a discharge space 24 surrounded by the lower casing 21, the upper casing 22, and the connecting casing 23.

  The operation unit 221 protruding in the front direction of the upper housing 22 includes, for example, an LCD touch panel 222. The operation unit 221 is formed so as to be able to input information related to image forming processing. For example, the user can input the number of sheets to be printed, the print density, and the like through the LCD touch panel 222. Housed in the upper housing 22 are mainly an apparatus for reading an image of a document and an electronic circuit that controls the entire image forming apparatus 1.

  A pressing cover 223 disposed on the upper housing 22 is used for pressing the document. The presser cover 223 is attached to the upper housing 22 so as to be rotatable up and down. The user rotates the holding cover 223 upward to place the document on the upper housing 22. Thereafter, the user can operate the operation unit 221 to cause the device for reading the document disposed in the upper housing 22 to read the image of the document.

  The lower casing 21 accommodates a cassette 211 formed so as to accommodate sheets. The cassette 211 can be pulled out from the lower housing 21 in the front direction. The sheets stored in the cassette 211 are subjected to an image forming process in the lower housing 21 based on an instruction input by the user through the operation unit 221, and are discharged into the discharge space 24.

  A tray 212 is rotatably attached to the right surface of the lower housing 21. As shown in FIG. 1, when the tray 212 is in a position protruding to the right of the lower housing 21, the user can place a sheet on the tray 212. The sheet on the tray 212 is drawn into the lower housing 21 based on an instruction input by the user through the operation unit 221, is subjected to image forming processing, and is discharged into the discharge space 24. When the tray 212 is rotated upward, the tray 212 is accommodated in the accommodation space 213 that is recessed in the right surface of the lower casing 21, and the supply port for drawing the sheet into the lower casing 21 is closed.

  The lower housing 21 accommodates various devices for forming an image on a sheet. Further, the connection housing 23 accommodates various devices for discharging the sheet subjected to the image forming process to the discharge space 24.

  FIG. 2 schematically shows the internal structure of the image forming apparatus 1 shown in FIG. The image forming apparatus 1 will be further described with reference to FIG. 1 in conjunction with FIG.

The upper housing 22 accommodates the scanning mechanism 224. The user can cause the image forming apparatus 1 to read an image of a desired document through the scanning mechanism 224. A contact glass 225 attached to the upper surface of the upper housing 22 is disposed on the scanning mechanism 224. The pressing cover 223 is used for pressing a document placed on the contact glass 225.
When the user operates the image forming apparatus 1 through the operation unit 221, the scanning mechanism 224 scans and reads an image of the document on the contact glass 225. Analog information of the image read by the scanning mechanism 224 is converted into a digital signal. The image forming apparatus 1 forms an image on a sheet based on the digital signal.

  The lower housing 21 includes toner containers 900Y, 900M, 900C, and 900K, an intermediate transfer unit 92, an image forming unit 93, an exposure unit 94, a fixing unit 97, a paper discharge unit 96, and a paper feed mechanism 500.

  The image forming unit 93 includes a yellow toner container 900Y, a magenta toner container 900M, a cyan toner container 900C, and a black toner container 900K. Below these containers, developing devices 10Y, 10M, 10C, and 10K corresponding to the respective colors of YMCK are disposed.

  The image forming unit 93 includes a photosensitive drum 17 (a photosensitive member on which a latent image is formed by an electrophotographic method) that carries toner images of respective colors. As the photosensitive drum 17, a photosensitive drum using an amorphous silicon (a-Si) material can be used. The photosensitive drums 17 are supplied with yellow, magenta, cyan, and black toners from the toner containers 900Y, 900M, 900C, and 900K, respectively.

  Around the photosensitive drum 17, a charger 16, a developing device 10 (10Y, 10M, 10C, 10K), a transfer device (transfer roller) 19 and a cleaning device 18 are arranged. The charger 16 uniformly charges the surface of the photosensitive drum 17. The surface of the photosensitive drum 17 after charging is exposed by the exposure unit 94 to form an electrostatic latent image. The exposure unit 94 emits laser light based on the digital signal generated by the scanning mechanism 224 described above. The developing devices 10Y, 10M, 10C, and 10K develop the electrostatic latent images formed on the respective photosensitive drums 17 using the toners of the respective colors supplied from the toner containers 900Y, 900M, 900C, and 900K, respectively ( Visualization). The transfer roller 19 forms a nip portion with the photosensitive drum 17 across the intermediate transfer belt 921, and primarily transfers the toner image on the photosensitive drum 17 onto the intermediate transfer belt 921. The cleaning device 18 cleans the peripheral surface of the photosensitive drum 17 after the toner image is transferred.

  The exposure unit 94 includes various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror. To form an electrostatic latent image.

  The intermediate transfer unit 92 includes an intermediate transfer belt 921, a driving roller 922, and a driven roller 923. On the intermediate transfer belt 921, toner images are overcoated from a plurality of photosensitive drums 17 (primary transfer). The overcoated toner image is secondarily transferred to a sheet supplied from the cassette 211 or the tray 212 (see FIG. 1) in the secondary transfer unit 98. A driving roller 922 and a driven roller 923 that rotate the intermediate transfer belt 921 are rotatably supported by the lower housing 21.

  The fixing unit 97 performs a fixing process on the toner image on the sheet secondarily transferred from the intermediate transfer unit 92. The sheet with the color image that has been subjected to the fixing process is discharged toward a paper discharge unit 96 formed in the upper part of the fixing unit 97 (in the connection housing 23).

  The paper discharge unit 96 discharges the sheet conveyed from the fixing unit 97 onto the upper surface 214 of the lower housing 21 used as a paper discharge tray.

  The cassette 211 stores a sheet bundle formed by stacking a plurality of sheets on which images are formed. As described above, the cassette 211 is detachably attached to the lower housing 21. When the pickup roller 40 provided in the cassette 211 is driven, the uppermost sheet of the sheet bundle in the cassette 211 is taken out one by one, fed out to the paper feed conveyance path 133, and introduced into the image forming unit 93. The

  The tray 212 is disposed above the cassette 211. The tray 212 shown in FIG. 2 is in a closed position for closing the paper feed port. The lower end portion of the tray 212 serves as a rotation shaft, and the tray 212 is rotated rightward so that a sheet bundle formed by stacking a plurality of sheets can be supported. A paper feed mechanism 500 is disposed near the lower end of the tray 212. The sheet feeding mechanism 500 plays a role as a sheet feeding device that feeds sheets placed on the tray 212 one by one to the image forming unit 93. The image forming unit 93 forms an image on the sheet fed into the lower housing 21 by the paper feed mechanism 500. The paper feed mechanism 500 will be described in detail in the following items.

(Description of paper feed mechanism 500)
FIG. 3 is a schematic perspective view of the paper feed mechanism 500 exposed to the outside by rotating the side walls of the lower housing 21 and the connecting housing 23 outward. The paper feed mechanism 500 is disposed in a region between the lower housing 21 and the base end edge serving as a rotation axis of the tray 212, and the paper set in the tray 212 is used to form the image forming unit 93 inside the lower housing 21. Send out towards the.

  As shown in FIGS. 5 to 6 and 8, the paper feed mechanism 500 of the present embodiment includes a base 520, a paper feed roller assembly 330, a bearing 341, a connecting portion 342, and a pin for turning the bearing 341. 345, a positioning member 343, and a leaf spring 344.

  As shown in FIGS. 5 to 6, the base portion 520 is a synthetic resin frame and accommodates the paper feed roller assembly 330. Both end portions in the axial direction of the sheet feed roller assembly 330 (specifically, a first end portion 333 and a second end portion 334 of a roller support portion 310 described later) are supported by a bearing 341 and a connecting portion 342.

  As shown in FIGS. 5 to 7, the paper feed roller assembly 330 includes a pair of paper feed rollers 335 that convey a sheet, and a roller support portion 310 that supports the pair of paper feed rollers 335.

  The paper feed roller 335 includes a pair of substantially cylindrical rollers, and is formed of a material (for example, rubber) that generates a sufficient frictional force on the surface of the sheet to convey the sheet. The sheets conveyed by the sheet feeding roller 335 are separated from other sheets by a separation pad 600 (see FIGS. 4 to 5) and sent out one by one.

  As shown in FIGS. 6 to 7, the roller support portion 310 is a shaft portion that is integrally fixed to the paper feed roller 335 so as to be coaxial with the paper feed roller 335, and has a first end at both ends in the axial direction. A portion 333 and a second end 334; The second end portion 334 has a cylindrical shape and has a space portion 334a therein.

  The roller support portion 310 shown in FIG. 7 includes a cylindrical first shaft portion 313 and a second shaft portion 314 slidably attached to the inside of the first shaft portion 313.

  A coil spring 315 is accommodated in the space portion 313 b of the first shaft portion 313. The coil spring 315 is compressed between the inner wall 313 a of the first shaft portion 313 and the opposing wall 314 a provided on the second shaft portion 314. As a result, the roller support portion 310 can expand and contract as the second shaft portion 314 moves in and out of the first shaft portion 313 while receiving the biasing force of the coil spring 315.

A first collar portion 337 is provided on the outer peripheral surface of the first shaft portion 313, and a second collar portion 338 is provided on the outer peripheral surface of the second shaft portion 314. As shown in FIGS. 10 to 11, the user holds the first collar portion 337 and the second collar portion 338 simultaneously with one hand or both hands, and moves the first collar portion 337 toward the second collar portion 338 in the direction of arrow A. By pushing to, the roller support portion 310 can be contracted in the direction in which the second end portion 334 is brought closer to the first end portion 333 . As shown in FIG. 7, the first collar portion 337 and the second collar portion 338 are disposed with the sheet feeding roller 335 interposed therebetween (that is, the sheet feeding roller 335 is interposed between the collar portions 337 and 338). Arrangement).

  Further, as shown in FIG. 7, a third collar portion 339 is provided on the outer peripheral surface at a position away from the tip of the second shaft portion 314 by a predetermined distance d. Therefore, when the first end portion 333 of the roller support portion 310 is inserted into the bearing 341, the third collar portion 339 comes into contact with the front end surface of the bearing 341, so that the first end portion 333 and the bearing 341 are fitted with each other. The axial length d (see FIGS. 7 and 9) can be ensured.

  As shown in FIGS. 5 to 6 and FIGS. 8 to 9, the bearing 341 is provided in the base portion 520 and supports the first end portion 333 of the roller support portion 310 in a rotatable and detachable manner.

  Specifically, as shown in FIGS. 8 to 9, the bearing 341 includes a main body portion 341a, a support portion 341b, and a connecting portion 341c, and these portions are integrally formed of a synthetic resin. The main body portion 341a has a cylindrical shape, and the first end portion 333 of the roller support portion 310 is inserted into the main body portion 341a, so that the first end portion 333 is rotatably supported. The first end 333 and the main body portion 341a may be fitted to each other as long as the first end portion 333 is supported by the main body portion 341a so as to be rotatable and detachable. The support portion 341b is a portion connected to the front end portion of the main body portion 341a. The connection portion 341c is a pair of protrusions that protrude upward, and is connected to the upper end of the support portion 341b.

  As shown in FIGS. 5 and 10 to 11, the connecting portion 342 is a portion provided at the tip of the drive shaft 300 that is rotationally driven by a motor (not shown). The connecting portion 342 is disposed at the base portion 520 so as to face the bearing 341. The connecting portion 342 is connected to the second end 334 of the roller support portion 310. Specifically, the connecting portion 342 is inserted into the space 334a (see FIG. 7) of the second end 334, so that the second end 334 is detachably connected. Since the inner peripheral surface of the second end 334 and the outer peripheral surface of the connecting portion 342 are uneven, it is possible to smoothly transmit the rotational driving force from the connecting portion 342 to the second end 334. It is.

  As shown in FIGS. 8 to 9, the pin 345 has the bearing 341 at a first position I (see FIGS. 10 to 11) facing the connecting portion 342 and a second position II (see FIG. 12) not facing the connecting portion 342. Slewing shaft (see FIG. 13). Further, the positioning member 343 is a member that contacts the bearing 341 and positions the bearing 341 at the first position I (see FIGS. 10 to 11).

  As shown in FIGS. 8 to 9, the positioning member 343 of the present embodiment is a member made of a thin metal plate or the like, and is fixed to the base portion 520 or integrally formed with the base portion 520. The positioning member 343 has a through hole 343a into which the bearing 341 and the first end 333 of the roller support portion 310 can be inserted. A pair of connecting portions 343b projecting upward is provided on the upper portion of the positioning member 343. A pair of connecting portions 343b of the positioning member 343 and a pair of connecting portions 341c of the bearing 341 are adjacent to each other by pins 345 in a state where they are adjacent to each other. Accordingly, the bearing 341 is positioned at the first position I in a state where the bearing 341 is in contact with the positioning member 343 as shown in FIGS. Further, the bearing 341 can turn between the first position I and the second position II by turning around the rotation center S of the pin 345.

  The leaf spring 344 is a biasing member that biases the bearing 341 from the first position I toward the second position II, as shown in FIGS. 8 to 9, and is made of a synthetic resin plate-like elastic body. Become. A base portion 344 b of the leaf spring 344 is connected to a support portion 341 b of the bearing 341. An intermediate portion of the leaf spring 344 extends from the support portion 341b toward the positioning member 343 along a predetermined opening angle. A tip portion 344 a of the leaf spring 344 is in contact with the front surface of the positioning member 343. The leaf spring 344 is integrally formed of a synthetic resin together with the bearing 341. However, the present invention may be a plate-like elastic body, and the material and shape thereof are not particularly limited.

  In the paper feed mechanism 500 configured as described above, the drive shaft 300 is in the gear cover 519 (see FIG. 5) with the pair of paper feed rollers 335 abutting against the leading edge of the sheet placed on the tray 212. ) By receiving a driving force from a driving source via an internal gear or the like, the sheet feeding roller assembly 330 can be rotationally driven via the connecting portion 342 at the tip of the driving shaft 300. At this time, the sheet can be fed into the lower housing 21 by the rotational force of the paper feed roller 335.

  Further, in this paper feed mechanism 500, when the paper feed roller assembly 330 is removed, the first end 333 and the second end 334 at both ends of the roller support portion 310 as shown in FIGS. From the state supported by the bearing 341 and the connecting portion 342 of the 520, first, as shown in FIGS. 10 to 11, the roller support portion 310 is operated by moving the first collar portion 337 in the arrow A direction. And the second end 334 is separated from the connecting portion 342. Next, as shown in FIGS. 12 to 13, in a state where the first end 333 of the roller support portion 310 is supported by the bearing 341, the sheet feeding roller assembly 330 and the bearing 341 are swung around the pin 345, and then By pulling out the feed roller assembly 330 in the direction of arrow B and removing the first end 333 from the bearing 341, the feed roller assembly 330 can be completely removed from the base 520. Thus, the sheet feeding roller assembly 330 can be easily removed in the order of the connecting portion 342 and the bearing 341.

  Further, since the bearing 341 is biased by the leaf spring 344 from the first position I to the second position II, the roller support portion 310 is contracted to connect the second end 334 of the roller support portion 310 to the connecting portion. When separated from 342, the bearing 341 and the paper feed roller assembly 330 can be easily turned from the first position I to the second position II by the urging force of the leaf spring 344.

  In addition, as shown in FIGS. 8 to 9 and FIGS. 12 to 13, when the bearing 341 is in the second position II, the leaf spring 344 is interposed between the bearing 341 and the positioning member 343 to place the bearing 341 in the second position II. Since it is held at the position II, the bearing 341 can be easily seen from the outside, and the paper feed roller assembly 330 can be easily attached.

(Features of this embodiment)
(1)
In the sheet feeding mechanism 500 of the present embodiment, in a state where the sheet feeding roller assembly 330 is attached to the base portion 520, the first end portion 333 and the second end portion 334 at both axial ends of the roller support portion 310 are respectively the base portion. 520 is supported by a bearing 341 and a connecting portion 342. When removing the paper feed roller 335 from this state , the roller support portion 310 is contracted by operating the first collar portion 337 by hand to release the second end portion 334 from the connecting portion 342, and then the roller support portion 310. The feed roller assembly 330 and the bearing 341 may be rotated around the pin 345 in a state where the first end portion 333 is supported by the bearing 341. Thus, both ends of the roller support portion 310 do not need to be separated from the bearing 341 and the connecting portion 342, respectively, and the paper feed roller assembly 330 can be easily removed in the order of the connecting portion 342 and the bearing 341.

  On the other hand, as a comparative example of the present invention, when a conventional structure in which the bearing 741 shown in FIG. 14 does not rotate is seen, when removing the paper feed roller assembly 330, the roller support part 310 is contracted so that both ends of the roller support part 310 are It can be seen that it is necessary to remove the paper feed roller assembly 330 in a state where the gaps g1 and g2 are secured at the same time from the bearing 741 and the connecting portion 742, and it is difficult to easily remove the paper feed roller assembly 330.

  Further, in the sheet feeding mechanism 500 of the present embodiment, as in the above-described conventional structure, the roller support portion 310 is contracted, and both ends of the roller support portion 310 are simultaneously separated from the bearing 341 and the connecting portion 342 to secure a gap. Therefore, it is not necessary to remove the paper feed roller assembly 330, so that the axial length d (see FIGS. 7 and 9) of the portion where the first end portion 333 of the roller support portion 310 and the bearing 341 are fitted is extended. Thus, it is possible to improve the mounting stability of the paper feed roller assembly 330. In addition, since the contact area between the first end 333 of the roller support portion 310 and the bearing 341 can be increased, wear at the contact portion between the roller support portion 310 and the bearing 341 can be reduced.

Further, the first collar portion 337 is provided on the first shaft portion 313, the second collar portion 338 is provided on the second shaft portion 314, and the first collar portion 337 and the second collar portion 338 are provided. The paper feed roller 335 is disposed therebetween. Therefore, the roller support part 310 can be contracted only by grasping the first collar part 337 and the second collar part 338 by hand.

(2)
Further, in the paper feed mechanism 500 of this embodiment, the bearing 341 is urged from the first position I to the second position II by the leaf spring 344. If the second end portion 334 of 310 is detached from the connecting portion 342, the bearing 341 and the paper feed roller assembly 330 can be easily swung from the first position I to the second position II by the biasing force of the leaf spring 344. Is possible.

(3)
Further, in the paper feed mechanism 500 of the present embodiment, when the bearing 341 capable of turning around the pin 345 is in the second position II, it is held at the second position II by the leaf spring 344. It is easier to see from the outside than when it is at the first position I, and it is easy to be connected. Therefore, when the paper feed roller assembly 330 is attached, the first end portion 333 of the roller support portion 310 can be easily connected to the bearing 341.

(4)
Further, in the paper feed mechanism 500 of the present embodiment, the leaf spring 344 is interposed between the bearing 341 and the positioning member 343, so that the bearing 341 is only in an angular range where the leaf spring 344 is interposed from the positioning member 343. It is possible to separate them. Therefore, the bearing 341 can be accurately held at the second position II by using the leaf spring 344 and the positioning member 343.

(5)
Further, in the paper feed mechanism 500 of the present embodiment, the plate spring 344 is used as the biasing member. Therefore, the bearing 341 is accurately moved by separating the bearing 341 from the positioning member 343 by the elastic force of the plate spring 344. It is possible to hold in the second position II. Further, when attaching the sheet feeding roller assembly 330, the bearing 341 can be easily returned to the first position I while the leaf spring 344 is bent. Further, when the bearing 341 is in the first position I, the leaf spring 344 is flattened, so that the space occupied by the leaf spring 344 is reduced. In addition, since the leaf spring 344 has a simple shape, it is easy to remove the mold at the time of resin molding, so that it is easily formed integrally with the bearing 341 using a synthetic resin.

  Instead of bringing the tip end portion 344a of the leaf spring 344 into contact with the positioning member 343, it may be brought into contact with another portion such as the inner wall of the base portion 520.

(6)
In the image forming apparatus 1 of the present embodiment, the paper feed mechanism 500 includes the paper feed mechanism 500 as described above. Therefore, the paper feed roller assembly 330 can be easily moved by turning the bearing 341 around the pin 345. Detachable. In addition, the axial length of the portion where the first end portion 333 of the roller support portion 310 and the bearing 341 are fitted can be extended, and the attachment stability of the paper feed roller assembly 330 can be improved. .

(Modification)
(A)
In the above-described embodiment, the example in which the leaf spring 344 as the biasing member is interposed between the bearing 341 and the positioning member 343 has been described. However, the present invention is not limited to this, and the biasing is performed. You may arrange | position a member in places other than the space pinched | interposed between the bearing 341 and the positioning member 343. FIG.

(B)
Moreover, in the said embodiment, although the example provided with the positioning member 343 which contacts the bearing 341 and positions the said bearing 341 in the said 1st position I is shown, this invention is not limited to this. Any means may be adopted as long as the pivotable bearing 341 can be positioned at the first position I. For example, a rotation restricting member that restricts the bearing 341 so that the bearing 341 can rotate by an angle range between the first position I and the second position II may be used.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 93 Image forming part 310 Roller support part 313 1st shaft part 314 2nd shaft part 330 Paper feed roller assembly 333 1st edge part 334 2nd edge part 335 Paper feed roller 341 Bearing 342 Connection part 343 Positioning member 344 Leaf spring (biasing member)
345 pin (swivel axis)
500 Paper feed mechanism (conveyance mechanism)
520 base

Claims (7)

The base,
A transport roller for transporting the sheet, a roller support portion that is fixed coaxially to the transport roller and is extendable in the axial direction, and has a first end and a second end at both ends in the axial direction ; and the second end A transport roller assembly having a first collar portion that is operated when the roller support portion is contracted in a direction to approach the first end portion ;
A bearing provided on the base and rotatably and detachably supporting the first end of the roller support;
A connecting portion that is disposed to face the bearing at the base, and the second end of the roller support portion is detachably connected;
A pivot shaft that supports the bearing so that the bearing can pivot between a first position facing the coupling portion and a second position not facing the coupling portion;
Transport mechanism, characterized in that it comprises a.   The roller support portion includes a first shaft portion and a second shaft portion that slide relative to each other,
  The first collar portion is provided on the first shaft portion,
  The transport roller assembly further includes a second collar portion provided on the second shaft portion,
  The first collar part and the second collar part are arranged with the conveying roller interposed therebetween,
The transport mechanism according to claim 1. A biasing member that biases the bearing from the first position toward the second position;
The transport mechanism according to claim 1 or 2. The biasing member holds the bearing in the second position when the bearing is in the second position;
The transport mechanism according to claim 3 . A positioning member that contacts the bearing and positions the bearing at the first position;
The biasing member is interposed between the bearing and the positioning member to hold the bearing in the second position;
The transport mechanism according to claim 4 . The biasing member is made of a plate-like elastic body.
The transport mechanism according to claim 3. A transport mechanism according to any one of claims 1 to 6 ;
An image forming apparatus comprising: an image forming unit that forms an image on the sheet transported by the transport mechanism.