JP6463142B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding device of an image forming apparatus using an electrophotographic recording method such as a copying machine, a facsimile machine, a laser beam printer, and a multifunction machine, and an image forming apparatus provided with the sheet feeding device.

  Conventionally, a retard separation system is used as a sheet feeding device of an image forming apparatus or a sheet feeding device of an automatic document feeder that separates and feeds stacked sheets one by one to an image forming unit or an image reading unit. The ones adopted are widely known.

  In the retard separation type sheet feeding apparatus, a sheet fed by a pickup roller is fed between a feed roller that rotates in the sheet feeding direction and a retard roller that is pressed against the feed roller by the elastic force of a spring. At the nip portion, the sheets are separated and conveyed one by one. The retard roller receives a predetermined torque value by a torque limiter, and when one sheet is fed, the retard roller is driven to rotate by the torque limiter. Further, when two or more sheets are fed to the nip portion between the feed roller and the retard roller, the retard roller has a friction coefficient between the sheets that is greater than the friction coefficient between the retard roller and the sheet. Since it is small, it stops and the second and subsequent sheets are stopped at the nip portion.

  By the way, since the required performances such as conveying force and durability are different for the pickup roller, the feed roller, the retard roller, and the like, rollers having different hardness and material may be set to improve the performance. For example, in order to prevent deterioration and wear of the feed roller and the retard roller, a technique has been proposed in which each roller is made of a different material and hardness (see Patent Document 1).

JP-A-8-175694

  By the way, as an example of a combination of each roller member of a pickup roller, a feed roller, and a retard roller, when durability is given priority, a configuration as described in Patent Document 1 may be used. That is, a roller member having higher hardness than the roller member of the pickup roller or the roller member of the feed roller may be used as the retard roller. This is because the retard roller is loaded with torque in a direction opposite to the sheet feeding direction via a torque limiter or the like, and thus wear easily proceeds as compared with other rollers.

  However, even if the combination of the rollers described in Patent Document 1 is good in terms of durability, when the rollers are replaced due to wear or the like, they are simply replaced with roller members of the same material. Thus, since there is no versatility in replacing the roller member, it is not possible to replace the other roller member and replace the part. For this reason, a roller having a high hardness has a lower conveying force than a roller having a low hardness. Depending on the type of the sheet to be fed, non-feeding may occur or the roller life may be shortened due to compatibility with the sheet. This problem may not be solved even after the replacement.

  The present invention provides versatility during replacement while satisfying the functions of different rollers, and avoids misfeeding of sheets, short life of rollers, etc. as a configuration that does not mistake the mounting destination of replaceable roller members. An object of the present invention is to provide a sheet feeding apparatus and an image forming apparatus.

The present invention provides a sheet feeding apparatus, wherein a sheet stacking unit on which sheets are stacked, a feeding roller that feeds a sheet stacked on the sheet stacking unit, and a sheet fed by the feeding roller are conveyed. A separation roller that presses against the conveyance roller and forms a separation nip portion between the conveyance roller and separates the sheets fed by the feeding roller one by one at the separation nip portion A first coupling part for attaching the feeding roller, a second coupling part for attaching the conveying roller, and a third coupling part for attaching the separation roller. The feeding roller can be attached to the first coupling unit, the second coupling unit, and the third coupling unit, and the transporting roller can be attached to the second coupling unit. Can only be attached to the coupling portion and the third coupling portion, the separation roller, the third is the attachable only to the coupling portion, characterized in that.

  According to the present invention, it is possible to provide versatility at the time of replacement while satisfying the functions of different rollers, and to avoid the mistaken attachment destination of the replaceable roller member, thereby avoiding sheet non-feeding, short roller life, etc. It becomes possible to do.

1 is a cross-sectional view schematically illustrating an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. FIG. 3 is a perspective view showing a roller holder and the like of the sheet feeding apparatus according to the present embodiment. The perspective view which shows the state which removed each roller member from the roller holder of FIG. (A)-(c) is a perspective view which shows the coupling part (shaft coupling) shape from which the roller member in this embodiment differs, respectively. The perspective view which shows the correspondence of each coupling part of the roller holder in this embodiment, and each roller member of a different property. The perspective view which shows the roller holder of the sheet feeding apparatus which concerns on this embodiment in the state which replaced the roller member.

  Hereinafter, an image forming apparatus including a sheet feeding apparatus according to an embodiment of the present invention will be described with reference to the drawings. The image forming apparatus according to the present embodiment can be configured from a copying machine, a multifunction machine, or the like.

[Image forming apparatus]
First, a schematic configuration of the image forming apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing an image forming apparatus 100 according to the present embodiment. In the following, a position facing a not-shown operation unit where the user performs various inputs and settings to the image forming apparatus 100 is referred to as “front side” of the image forming apparatus 100, and a rear side is referred to as “back side”. That is, FIG. 1 shows the internal configuration of the image forming apparatus 100 viewed from the front side.

  As shown in FIG. 1, the image forming apparatus 100 reads an image of a document (sheet-like document) G stacked on a document stacking tray 221 and an image read by the image reading device 200. An apparatus main body 10 that can be formed on the sheet S is provided. The image forming apparatus 100 includes a control unit 50 that controls the image reading apparatus 200, the apparatus main body 10, and the like.

  The image reading apparatus 200 includes a scanner unit 210 that reads an image of a document (sheet) G, and an automatic document transport device (hereinafter referred to as ADF) 220 that can automatically feed the document G to the scanner unit 210. ing. Note that reference numeral 211 denotes a first reading unit that is used when the front surface (first surface) of the original G is scanned or fixed, and reference numeral 251 is a first reader that is used when the rear surface (second surface) of the original G is continuously scanned. 2 shows a reading unit.

  The apparatus main body 10 includes an image forming unit 20 that forms an image on a sheet S that is a recording medium, and a sheet feeding unit 30 that feeds the sheet S to the image forming unit 20. Further, the apparatus main body 10 includes a discharge roller pair (discharge unit) 46 that discharges the sheet S on which an image has been formed to the outside of the apparatus main body 10 (outside the apparatus), and a sheet discharge tray 45 on which the discharged sheets S are stacked. have.

  The image forming unit 20 fixes the toner image, the photosensitive drum 22 on which the toner image is formed, the laser scanner unit 21 that irradiates the photosensitive drum 22 with laser light, the transfer unit 24 that transfers the toner image to the sheet S, and the toner image. And a fixing unit 25. A registration roller pair 11 is disposed upstream of the transfer unit 24 in the sheet conveyance path. The image forming unit 20 constitutes an image forming unit that forms an image on a sheet S fed from a sheet stacking plate 31a described later.

  The sheet feeding unit 30 includes a sheet feeding cassette 31 having a sheet stacking plate 31 a on which the sheets S are stacked, and a pickup roller (feeding) for feeding the sheet S stacked on the sheet stacking plate 31 a in the sheet feeding cassette 31. Roller) 32. Further, the sheet feeding unit 30 includes a feed roller (conveying roller) 33 that conveys the sheet S fed by the pickup roller 32. Further, the sheet feeding unit 30 is in pressure contact with the feed roller 33 to form a separation nip N between the sheet feeding roller 33 and the sheet S fed by the pickup roller 32 one by one at the separation nip N. A retard roller (separation roller) 34 is separable. Reference numeral 27 denotes a sheet feeding unit which will be described later, and reference numeral 29 denotes a drawing roller for conveying the sheets separated by the sheet feeding unit.

  In the present embodiment, the pickup roller 32, the feed roller 33, and the retard roller 34 have the same outer diameter so that they can be used together. The sheet stacking plate 31a constitutes a sheet stacking unit on which sheets S are stacked.

  Next, an image forming operation of the image forming apparatus 100 will be described. Here, an image forming operation for forming an image on the sheet S based on the image information of the original G automatically fed by the ADF 220 and read by the scanner unit 210 will be described.

  That is, when image information of the document G fed by the ADF 220 and read by the scanner unit 210 is input, the laser beam is irradiated from the laser scanner unit 21 to the photosensitive drum 22 based on the input image information. . At this time, the photosensitive drum 22 is charged in advance via the charging member 26, and an electrostatic latent image is formed by irradiation with laser light. The electrostatic latent image is developed by the developing device 23 and formed as a toner image on the photosensitive drum 22.

  In parallel with the operation of forming the toner image on the photosensitive drum 22, the sheet S stored in the sheet feeding cassette 31 of the sheet feeding unit 30 is fed by the pickup roller 32. The sheets S fed by the pickup roller 32 are nipped by a separation nip portion N between the feed roller 33 and the retard roller 34, and are separated and conveyed one by one.

  The sheets S separated one by one are synchronized with the toner image on the photosensitive drum 22 by the registration roller pair 11 and are sent to the transfer unit 24. The toner image on the photosensitive drum 22 is transferred to the sheet S sent to the transfer unit 24 by the transfer unit 24.

  The sheet S to which the toner image has been transferred is heated and pressed by the fixing unit 25, and the toner image is melted and fixed to the sheet S. The sheet S on which the toner image is fixed is discharged to the sheet discharge tray 45 by the discharge roller pair 46 and is sequentially stacked. When images are formed on both sides of the sheet S, after the image is fixed on the first side of the sheet S, the sheet S is re-conveyed toward the registration roller pair 11 via the reverse conveyance path 12. The above operation is repeated.

[Sheet feeding device]
Next, details of the sheet feeding unit (sheet feeding apparatus) 30 according to the present embodiment will be described with reference to FIGS. 1 to 4. FIG. 2 is a perspective view showing a roller holder and the like of the sheet feeding apparatus according to the present embodiment. FIG. 3 is a perspective view showing a state in which each roller member is removed from the roller holder of FIG. 2. FIGS. 4A to 4C are perspective views showing different coupling (shaft coupling) shapes of the roller members in this embodiment.

  As shown in FIGS. 1 and 2, the sheet feeding unit 30 provided in the apparatus main body 10 includes a sheet feeding unit 27. The sheet feeding unit 27 includes a feeding unit unit U1 and a separation unit unit. U2. In the sheet feeding unit 27, the feeding unit unit U1 and the separation unit unit U2 are connected as one unit via a connecting means such as a screw. The sheet feeding unit 27 constitutes a roller support unit that supports the pickup roller 32, the feed roller 33, and the retard roller 34 so as to have a predetermined positional relationship (the positional relationship shown in FIG. 2).

  The feeding unit unit U1 includes a feeding frame 47. The feeding frame 47 is provided with a pickup roller shaft 41 that rotatably supports the roller member 32a of the pickup roller 32 at one end. Further, the feed frame 47 is rotatably supported by a feed roller shaft 42 provided with a roller member 33a of the feed roller 33 at one end. The feed roller shaft 42 is driven by a drive source such as a motor (not shown). The rotation of is transmitted. The feeding unit unit U1 is based on the main body of the sheet feeding unit 30 and supports the feeding frame 47 so as to be rotatable about the feed roller shaft 42 as a fulcrum. The rotation operation (elevating operation) of the feeding frame 47 is provided so as to be interlocked with a link member (not shown), and is interlocked with the operation of taking in and out the apparatus main body 10 of the paper feed cassette 31 (FIG. 1). It is configured to move up and down.

  The separation unit U2 has a separation frame 28 that is rotatably supported by a frame (not shown). A retard roller shaft 43 provided with a roller member 34a of the retard roller 34 at one end is supported on the separation frame 28 so as not to rotate. The retard roller shaft 43 is provided with a torque limiter 39, and a roller member 34 a of the retard roller 34 is attached to the torque limiter 39. The separation frame 28 is biased upward by a spring (not shown), so that the retard roller 34 is pressed against the feed roller 33 to generate a nip pressure at the separation nip portion N.

  In the retard roller 34, no driving force is input to the retard roller shaft 43, and a roller member 33 a is attached to the retard roller shaft 43 via a torque limiter 39. When the load applied to the retard roller 34 from the feed roller 33 via the sheet is equal to or greater than a predetermined torque value (limit value) of the torque limiter 39, the retard roller 34 is rotated along the sheet and is equal to or less than the predetermined torque value. The retard roller 34 stops.

  That is, the roller member 34a of the retard roller 34 receives a predetermined torque value via the torque limiter 39 or the like. The torque value is set larger than the friction force generated between the sheets due to the friction coefficient between the sheets and smaller than the friction force generated due to the friction coefficient between the sheet S and the feed roller 33. As a result, when one sheet S enters the separation nip N between the feed roller 33 and the retard roller 34 or when no sheet enters, the retard roller 34 rotates with the feed roller 33 (driven). Rotate. On the other hand, when two or more sheets S enter the separation nip portion N between the feed roller 33 and the retard roller 34, the retard roller 34 stops the retard roller 34 without being rotated. Separate one by one. In this way, the sheets S fed by the pickup roller 32 are separated and conveyed one by one by the separation nip portion N.

  A coupling part 35 for attaching the roller member 32a is rotatably attached to the pickup roller shaft 41, and a gear 35c is provided in the coupling part 35. The feed roller shaft 42 is provided with a one-way clutch 37, and a roller member 33 a is attached via the one-way clutch 37. The one-way clutch 37 is provided so that the driving is interrupted while the sheet is being fed, and the roller member 33a rotates with the sheet when the driving is interrupted. The one-way clutch 37 is also provided with a gear 37c, and the gear 35c and the gear 37c are engaged with the gear 44, respectively. With this configuration, when the rotation of the drive motor (not shown) is transmitted to the feed roller shaft 42 of the feed roller 33, the rotation of the feed roller shaft 42 is transmitted to the pickup roller 32 via the gear 44. Thereby, the pickup roller 32 is rotated in the same direction as the feed roller 33.

  The pickup force by the pickup roller 32 is configured to be pressed against the sheet S in the sheet feeding cassette 31 by a pickup pressurizing spring (not shown) that is a torsion coil spring. The pickup pressurizing spring has a coil portion coaxially provided with the feed roller shaft 42, an end portion on the working side is hooked on the feeding frame 47, and an end portion on the fixed side is fixed to the apparatus main body side. As a result, the pickup roller 32 is pressed against the sheet S with a predetermined pressure.

  In this embodiment, when the sheet feeding cassette 31 (see FIG. 1) is inserted into the apparatus main body 10, the sheet stacking plate 31a on which the sheets S are stacked is lifted up. When the sheet stacking plate 31a is lifted up and the sheet S comes into contact with the pickup roller 32 attached to the lowered feeding frame 47, the feeding frame 47 is pushed up, and the sheet stacking plate is detected based on detection by a photosensor (not shown). The lift-up of 31a is stopped. Thereby, the position of the upper surface of the sheet S stacked on the sheet stacking plate 31a can always be positioned within a certain range, and the pickup pressure can be stabilized.

  On the other hand, when the paper feed cassette 31 is pulled out from the apparatus main body 10, the feed frame 47 is raised. This is to prevent the pickup roller 32 from dragging the sheet when the sheet feeding cassette 31 is pulled out by raising the pickup roller 32 from the state in contact with the sheet surface and separating the pickup roller 32 from the sheet surface. It is. The feeding frame 47 is provided with a sheet presence / absence detection lever (not shown), and the presence / absence of the sheet S set on the sheet stacking plate in the sheet feeding cassette 31 is detected by the sheet presence / absence detection lever. .

[Roller support structure of sheet feeding unit]
Next, with reference to FIGS. 3 to 5, a description will be given with reference to FIGS. 3 to 5 of a coupling portion or the like provided with a predetermined correspondence relationship so that a plurality of roller members can be reliably attached as pickup rollers or the like. To do. FIG. 5 is a perspective view showing the correspondence between each coupling portion of the roller holder and each roller member having a different property.

  As shown in FIGS. 3-5, each roller shaft 41,42,43 and each roller member 32a, 33a, 34a are each connected by the coupling. The feed roller shaft 42 and roller member 33a have a one-way clutch 37 having a coupling function, and the retard roller shaft 43 and roller member 34a have a torque limiter 39 having a coupling function. Therefore, hereinafter, the one-way clutch 37 and the torque limiter 39 will be described as a coupling portion. The coupling portions 35, 37, 39 have engaging portions 36, 38, 40 that can engage the corresponding one of the first, second, and third roller members 32 a, 33 a, 34 a. The first to third roller members 32a to 34a have engaged portions 51, 52, and 53 that can be engaged with corresponding ones of the engaging portions 36, 38, and 40. The engaging portions 36, 38, and 40 are configured to feed sheets so that the pickup roller 32, the feed roller 33, and the retard roller 34, which are replaceable among the first to third roller members 32 a to 34 a, can be engaged. It is provided on the unit 27 side (roller support means side). In the present embodiment, the first to third roller members (roller members) 32a to 34a have the same outer diameter so that they can be used together.

  As shown in FIG. 5, the engaging portion 36 corresponding to the pickup roller 32 has a shape that can be engaged only with the engaged portion 51 of the first roller member 32a. The engaging portion 38 corresponding to the feed roller 33 has a shape that can be engaged with the engaged portions 51 and 52 of the first and second roller members 32a and 33a in common. The engaging portion 40 corresponding to the retard roller 34 has a shape that can be engaged with the engaged portions 51 to 53 of the first, second, and third roller members 32a to 34a in common. Further, the engaged portions 51 to 53 are arranged on the first to third roller members 32 a to 34 a side (roller member side) so as to be able to engage with a specific one of the engaging portions 36, 38, and 40. Each is provided.

  The engaging portions 36, 38, and 40 and the engaged portions 51 to 53 constitute attachment means. This attachment means is within a range in which a plurality of types (three types in this embodiment) of first to third roller members 32a to 34a made of materials having different properties can be substituted as the rollers 32, 33, and 34. Can be attached to the sheet feeding unit 27 only.

  The first roller member 32 a is configured to be used as the pickup roller 32, the feed roller 33, and the retard roller 34. The second roller member 33a is configured to be used as both the feed roller 33 and the retard roller 34. The third roller member 34 a is configured to be usable only as the retard roller 34. Thereby, it becomes possible to attach only the roller member which can substitute material.

  Examples of materials having different properties of the first to third roller members 32a, 33a, and 34a that can be employed for the pickup roller 32, the feed roller 33, and the retard roller 34 include the following combinations. The following hardness (rubber hardness) is measured by the JIS spring method.

  That is, the hardness of the first roller member 32a is set in a range of 24 to 44 [°], the hardness of the second roller member 33a is set in a range of 43 to 63 [°], and the hardness of the third roller member 34a is set. It is set in the range of 65 to 85 [°]. The first roller member 32a is made of EPDM (Ethylene Propylene Rubber). The second roller member 33a and the third roller member 34a are each made of urethane resin.

The reason for setting in this way is that the load applied to the surfaces of the pickup roller 32, the feed roller 33, and the retard roller 34 when the durability is considered,
Pickup roller 32 <feed roller 33 <retard roller 34
This is because of the relationship. The reason is that the retard roller 34 having a large load cannot adopt the first roller member 32a or the second roller member 33a having a relatively high conveying force and a low hardness.

  However, the third roller member 34a having a high hardness employed for improving the durability of the retard roller 34 has a relatively low conveying force, and therefore, depending on the type of the sheet to be conveyed, non-feeding may occur or the addition of the sheet may be performed. Depending on the compatibility with the agent, the life may be shortened. Furthermore, there may be a problem that an image mark appears in an area through which the third roller member 34a has passed due to charging with the sheet. Similarly, the feed roller 33 may have problems such as non-feeding, short life, and image traces when passing a sheet that requires more conveying force.

  In order to deal with these problems, as described above, the first roller member 32a having a relatively high conveying force or different material is used as the pickup roller 32, the feed roller 33, and the retard roller 34. . Further, the second roller member 33a is configured to be used also as the feed roller 33 and the retard roller 34. Further, the second roller member 33 a having a higher conveying force than the third roller member 34 a is configured to be used only as the retard roller 34.

  Here, with reference to FIG. 3, FIG. 4 (a)-(c), and FIG. 5, the engaging parts 36, 38, and 40 of the coupling parts 35, 37, and 39 and the first to third roller members 32a, The engaged portions 51, 52, 53 of 33a, 34a will be described.

  That is, the engaged portion 51 in the first roller member 32a includes two first elongated hole portions 51c provided at two positions opposed to each other with a rotation shaft hole 51a inserted through the pickup roller shaft 41 as a center. And a protruding portion 51b provided between the first elongated hole portions 51c. The engaging portion 36 of the coupling portion 35 is provided at two positions opposed to each other with a rotation shaft hole 35a inserted through the pickup roller shaft 41 as a center, and can be inserted into the first elongated hole portion 51c. And a recess 36b provided between the two first protrusions 36a.

  The engaged portion 52 of the second roller member 33a includes second hole portions 52c provided at four positions facing each other around a rotation shaft hole 52a inserted through the feed roller shaft 42, and second portions of these four positions. And a protrusion 52b provided between the holes 52c. Engagement portions 38 of the coupling portion 37 are provided at four opposing positions around the rotation shaft hole 37a inserted through the feed roller shaft 42, and are respectively inserted into the second protrusions 38a that can be inserted into the second holes 52c. And a recess 38b provided between the four second protrusions 38a.

  The engaged portion 53 in the third roller member 34 a includes third hole portions 53 c provided at two positions facing each other around the rotation shaft hole 53 a inserted through the retard roller shaft 43, and third portions of these two positions. And a protrusion 53b provided between the holes 53c. The engaging part 40 of the coupling part 39 is provided at two opposite positions around the rotation shaft hole 39a inserted through the retard roller shaft 43, and is provided with a third projecting part 40a that can be inserted through the third hole part 53c. A recess 40b provided between the two third protrusions 40a.

  With the above configuration, the engaging portion 36 corresponding to the pickup roller 32 can be engaged only with the engaged portion 51 of the first roller member 32a. Further, the engaging portion 38 corresponding to the feed roller 33 can be engaged only with the engaged portions 51 and 52 of the first roller member 32a and the second roller member 33a. Further, the engaging portion 40 corresponding to the retard roller 34 can be engaged only with the engaged portion 53 of the third roller member 34a.

  Accordingly, the first roller member 32a used as the pickup roller 32 can be used also as the feed roller 33 and the retard roller 34, and the second roller member 33a used as the feed roller 33 can also be used as the retard roller 34. it can. Further, the third roller member 34 a can be used only as the retard roller 34.

  Therefore, for example, as shown in FIG. 6, the first roller member 32 a is attached to the coupling portion 35 of the sheet feeding unit 27 as the pickup roller 32, and the first roller member 32 a is attached to the coupling portion 37 as the feed roller 33. it can. Further, the second roller member 33 a can be attached to the coupling portion 39 as the retard roller 34. Even with such a combination, it is possible to cope with a problem caused by the conveyed sheet.

  It should be noted that the relationship between the hole and the protrusion described above can be reversed. That is, the first elongated hole portion 51c, the second elongated hole portion 52c, the third elongated hole portion 53c, and the like are formed on the coupling portions 35, 37, 39 side, and the first protruding portion 36a, the second protruding portion 38a, and the second One protrusion 40a or the like may be formed on the first to third roller members 32a, 33a, 34a side. In this case, the same effect can be obtained.

  In addition, the shapes of the first elongated hole portion 51c, the second elongated hole portion 52c, the third elongated hole portion 53c, the first protruding portion 36a, the second protruding portion 38a, the first protruding portion 40a, and the like described above are as described above. It is not limited. That is, the first roller member 32a can be used as the rollers 32, 33 and 34, the second roller member 33a can be used as the rollers 33 and 34, and the third roller member 34a can be used only as the retard roller 34. Other shapes may be used as long as they are satisfied. In that case, the same effect can be obtained.

  According to the present embodiment described above, it is possible to prevent erroneous assembly such that the second roller member 33a is used as the pickup roller 32 or the third roller member 34a is used as the pickup roller 32 or the feed roller 33. it can. Accordingly, it is possible to provide versatility during replacement while satisfying the functions such as hardness of the different rollers 32, 33, and 34, and to prevent mistaken attachment destinations of replaceable roller members. This makes it possible to use a roller having an appropriate hardness according to the sheet to be fed, and to avoid sheet non-feeding, a short roller life, and the like that occur according to the type of paper used.

  20 ... Image forming unit (image forming unit) / 27 ... Sheet feeding unit (roller supporting unit) / 30 ... Sheet feeding unit (sheet feeding device) / 31a ... Sheet stacking plate (sheet stacking unit) / 32 ... Pickup Roller (feed roller) / 32a ... first roller member (roller member) / 33 ... feed roller (conveyance roller) / 33a ... second roller member (roller member) / 34 ... retard roller (separation roller) / 34a ... first 3 roller members (roller members) / 36, 38, 40... Engaging portions (attachment means) / 51, 52, 53... Engaged portions (attachment means) / 100... Image forming apparatus / N. ... Sheet

Claims (6)

Sheet stacking means on which sheets are stacked;
A feeding roller for feeding the sheets stacked on the sheet stacking means;
A conveying roller for conveying the sheet fed by the feeding roller;
A separation roller that presses against the conveyance roller to form a separation nip portion with the conveyance roller, and separates the sheets fed by the feeding roller one by one at the separation nip portion;
A first coupling portion for attaching the feeding roller;
A second coupling part for attaching the conveying roller;
A third coupling part for attaching the separation roller,
The feeding roller can be attached to the first coupling unit, the second coupling unit, and the third coupling unit,
The transport roller can be attached only to the second coupling part and the third coupling part,
The separation roller can be attached only to the third coupling portion.
A sheet feeding apparatus characterized by that. The first coupling portion has a shape that can be engaged only with an engaged portion of the feeding roller ,
The second coupling part has a shape that can be engaged with the engaged parts of the feeding roller and the conveying roller in common,
The third coupling portion has a shape that can be engaged with the engaged portions of the feeding roller, the conveying roller, and the separation roller in common.
The sheet feeding apparatus according to claim 1 .   The feeding roller, the conveying roller, and the separation roller are made of different materials from each other.
  The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. Each hardness according to the JIS spring type of the materials having different properties is
The feeding roller is set in a range of 24 to 44 [°],
The conveyance roller is set in a range of 43 to 63 [°],
The separation roller is set in a range of 65 to 85 [°].
The sheet feeding apparatus according to claim 3 . In the materials having different properties,
The feeding roller is composed of EPDM,
The transport roller and the separation roller are each made of urethane resin.
Sheet feeding apparatus according to claim 3 or 4, characterized in that. A sheet feeding device according to any one of claims 1 to 5 ,
Image forming means for forming an image on a sheet fed from the sheet feeding device ,
An image forming apparatus.

Images