JP2017165546A - Sheet feeding device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device and image formation apparatus which have a configuration as simple as possible, can prevent plastic deformation or the like of a separation guide even when the removal work for a residual sheet held between a separation conveyance roller pair is performed and facilitate the replacement work for the separation guide.SOLUTION: A manual feeding part includes: a feeding tray on which sheets are loaded; a separation conveyance roller pair 78 which separates sheets fed from the feeding tray one by one at a nip part for conveyance; and a support frame 55 which supports a retarded roller 76 of the separation conveyance roller pair 78. The manual feeding part includes: a separation guide plate 56 whose lower end surface is detachably fixed to the support frame 55 in such a form that an upper end surface 56a is positioned so as to guide the sheets to the nip part on the upstream in the sheet conveyance direction of the separation conveyance roller pair; and feeding introduction guides 54F, 54R which are detachably fixed to the support frame 55 in such a form that the lower end surface is supported by covering it from the upstream side in the sheet conveyance direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet feeding apparatus that is provided in an image forming apparatus such as a copying machine or a printer and that can feed sheets.

  An image forming apparatus such as a copying machine or a printer is provided with a feeding tray on which sheets are stacked and a feeding mechanism for feeding the sheets, and an image forming unit in the apparatus main body at a predetermined timing. There is known a sheet feeding apparatus configured to feed one sheet at a time. The sheet feeding apparatus includes a pickup roller that picks up a sheet, a feed roller that conveys the picked-up sheet, and a retard roller that separates the sheets one by one when they are conveyed by a pickup operation. In this sheet feeding apparatus, a separation conveyance roller pair is constituted by a feed roller and a retard roller.

  In this sheet feeding apparatus, when using a sheet having a thick and high rigidity to be fed, the sheet bundle fed by the pickup roller feeds the retard roller while trying to enter the pair of separation conveying rollers. It may be pushed down in the direction away from the roller. In this state, the feeding force of the feed roller to the first sheet is reduced and a conveyance failure occurs, or the separation performance by the retard roller is not exhibited, and multiple sheets are fed at once. The so-called double feed may occur.

  In order to solve this problem, a sheet feeding apparatus is known in which a separation guide is arranged immediately before the upstream side of the pair of separation conveyance rollers. In this sheet feeding device, the leading edge of the sheet having high rigidity and a high friction coefficient between the sheets is spread with a separation guide, and the leading edge of the sheet is guided so as to be as parallel as possible to the nip line of the separation conveying roller pair. The feeding state is made appropriate. The separation guide is arranged in the vicinity of the nip portion of the separation conveyance roller pair, and is configured so as to obtain an appropriate feeding state by cooperating with a separation auxiliary guide integrally attached to the outer side of the separation guide ( Patent Document 1).

Japanese Patent Laid-Open No. 2001-163472

  By the way, the separation guide and the separation auxiliary guide described in Patent Document 1 have a higher effect of preventing a phenomenon in which a plurality of highly rigid sheets enter the nip portion as the rigidity increases. On the contrary, when the separation guide and the separation auxiliary guide are low in rigidity, when the bundle of sheets having high rigidity tries to enter the nip portion, the separation guide and the separation auxiliary guide are deformed and the retard roller is moved away from the feed roller. May be moved away (downward). In such a case, the deformation of the separation guide and the separation auxiliary guide may cause conveyance failure and double feeding. Accordingly, it is preferable that the separation guide and the separation auxiliary guide are made of a material having a high rigidity such as a metal plate rather than a material having a low rigidity such as a PET sheet.

  However, if a paper jam occurs in any part of the sheet transport path, the residual sheet that moves is removed when pulling the residual sheet sandwiched between the nip portions of the separation transport roller pair in the direction opposite to the transport direction. There is a risk of deforming the separation guide or the separation auxiliary guide. In particular, when a highly rigid separation guide or separation auxiliary guide is deformed, there is a problem that these guides are plastically deformed or fall off.

  In the technique of Patent Literature 1, in order to increase the rigidity of the separation guide, a complicated state in which a separation auxiliary guide fixed on the upper side of the separation guide with an adhesive or the like is sandwiched between nip portions of the separation conveyance roller pair. Configuration is required. Therefore, even if the operation is performed by pulling and removing the residual sheet sandwiched between the pair of separation conveyance rollers, the separation guide or the like is composed of thin members having low rigidity and is as simple as possible. A configuration that does not plastically deform or drop off is desired.

  The present invention can prevent the plastic deformation of the separation guide even if the removal operation of the residual sheet sandwiched between the separation conveyance roller pair is performed while having a simple configuration as much as possible, and the replacement operation is also possible. An object is to provide a sheet feeding apparatus and an image forming apparatus having an easy configuration.

  The present invention provides a sheet feeding apparatus in which a sheet stacking unit for stacking sheets and a sheet fed from the stacking unit are separated and conveyed one by one at a nip portion formed in contact with each other. A roller and a separation roller; a support unit that supports the separation roller; a guide unit that guides the sheet to the nip portion; and a fixing unit that is fixed to the support unit; A separation guide plate that is detachably fixed to the support means, and the fixing portion is covered from the upstream side in the sheet conveying direction with the guide portion of the separation guide plate exposed. And a support cover member that is detachably fixed to the support means in a supported form.

  According to the present invention, the plasticity of the separation guide is obtained even when the removal operation of the residual sheet sandwiched between the separation conveyance roller pair is performed while having a simple structure as much as possible with a thin member having low rigidity. Deformation and the like can be prevented, and the replacement work can be easily performed.

1 is a schematic configuration diagram showing an image forming apparatus according to an embodiment of the present invention. The perspective view which shows the manual feed part which concerns on this embodiment. The perspective view which shows the feeding part in the manual feeding part which concerns on this embodiment. The perspective view which shows the feeding part in FIG. 3 in the state which removed the feeding introduction guide. Sectional drawing which cut | disconnects and shows the feeding part in FIG. 3 by the near side of a retard arm. Sectional drawing which expands and shows the nip part of a separation conveyance roller pair, and its vicinity. (A) is a schematic diagram showing an example during a paper jam processing in a comparative example, (b) is a schematic diagram showing an example during a paper jam processing in the present embodiment. The disassembled perspective view which shows the state at the time of parts replacement | exchange in a feeding part.

  Hereinafter, an image forming apparatus such as a digital copying machine or a printer that forms an image using an electrophotographic method will be described as an example with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. It is not intended to limit the scope of the invention only to them.

  As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body (apparatus main body) 100a, and a reader unit 21 having a scanning optical system for reading an image is disposed on the upper part of the apparatus main body 100a. An image forming unit 17 is disposed below the reader unit 21. The image forming unit 17 is disposed below the image forming units 1Y, 1M, 1C, and 1K for forming the read image on the sheet S, the scanner units 13Y, 13M, 13C, and 13K, and the image forming units 1Y to 1K. The intermediate transfer belt (intermediate transfer member) 31 is provided.

  The lower side of the apparatus main body 100a is provided with a plurality of stages of front loading type paper feed cassettes 61, 62, 63, and 64 that accommodate sheets S and are mounted so as to be inserted and extracted from the front side of the apparatus main body 100a. Yes. In a feeding portion corresponding to each of the sheet feeding cassettes 61 to 64, a sheet feeding unit 36 including a pickup roller 71 and a separation conveyance roller pair including a feed roller 37 and a retard roller 38 is disposed. Further, on the side (right side) of the apparatus main body 100a in the drawing, manual feeding as a sheet feeding apparatus in which the sheet S is set on a feeding tray 18 disposed outside the apparatus main body 100a. Part 2 is arranged. The feeding tray 18 as a stacking means constitutes a manual feed tray arranged on the side of the apparatus main body 100a.

  In the manual feeding unit 2, a pickup roller (feeding roller) 70 that picks up the sheets S stacked on the feeding tray 18 is disposed downstream of the feeding tray 18 in the sheet feeding direction (sheet conveying direction) D. A separation conveyance roller pair 78 is disposed. The image forming unit 17 described above constitutes an image forming unit that forms an image on the sheet S conveyed by the separation conveying roller pair 78.

  The image information read by the reader unit 21 is photoelectrically converted by the scanner units 13Y to 13K, transferred to the corresponding ones of the image forming units 1Y to 1K, and the photosensitive drums 11Y to 11K in the image forming units 1Y to 1K, respectively. Each is formed as a toner image. The toner images on the photosensitive drums 11Y to 11K are transferred to the intermediate transfer belt 31 by the primary transfer portions 35Y, 35M, 35C, and 35K, and are conveyed to the secondary transfer portion T by the intermediate transfer belt 31.

  In the secondary transfer unit T, the toner image is transferred to one of the sheet feeding cassettes 61 to 64 or the sheet S sent from the manual feeding unit 2 and then conveyed to the fixing device 5 where heat and pressure are transferred. Is applied and fixed to the sheet S. Thereafter, when the single-sided image forming mode is selected by the designation of the user (operator), the sheet S is removed from the outside of the apparatus main body 100a (from the discharge port 50 provided on the other side of the apparatus main body 100a). Discharged outside the machine. On the other hand, when the double-sided image forming mode is selected, it is sent again to the image forming unit 17 via the reverse path 52 and the double-sided path 85 by the path switching means 51a and 51b.

[Main configuration of this embodiment]
Hereinafter, the main configuration in the present embodiment will be described with reference to FIGS. In the present embodiment, a configuration example in which the present invention is applied to the manual feeding unit 2 will be described. FIG. 2 is a perspective view showing the manual feed unit 2 according to the present embodiment.

  As shown in FIG. 2, the manual feeding unit 2 includes a tray unit 19 having a feeding tray 18 on which sheets S are stacked. Further, the manual feeding unit 2 includes side regulating plates 16F and 16R that regulate the position in the width direction of the sheets S stacked on the feeding tray 18, and a feeding unit that feeds the sheets S into the apparatus main body 100a. 23.

  A holding tray 24 that can be held at a position opened at a fixed angle with respect to the apparatus main body 100a (FIG. 1) is attached to the lower portion of the tray unit 19 in FIG. In the holding tray 24, the tray arm 3 is fixed to the front end and the back end in FIG. 2, respectively. Each of the tray arms 3 at the front end and the rear end is provided with a tray rotation support portion 9.

  When the tray rotation support portion 9 of each tray arm 3 is engaged with the support shaft 33 (see FIG. 1) of the apparatus main body 100a, the feeding tray 18 rotates in the vertical direction with the tray rotation support portion 9 as a fulcrum. It is supported movably. The feeding tray 18 is provided with a slide groove 26 that slidably engages the side regulating plates 16F and 16R so as to extend along the width direction E perpendicular to the sheet feeding direction (sheet conveying direction) D. The side regulating plates 16F and 16R are supported so as to be slidable along the width direction E by engaging with the slide groove 26.

  The feeding unit 23 includes a pickup roller (feeding roller) 70 supported by the pickup roller shaft 8 so as to pick up the sheets S stacked on the feeding tray 18, and a separation conveyance roller pair 78. . The separating and conveying roller pair 78 includes a retard roller (separating roller) 76 and a feed roller (conveying roller) 77 supported by the feed roller shaft 80 so as to contact the retard roller 76 and convey the sheet S. . The retard roller 76 is brought into contact with the feed roller 77, so that a nip portion N (see FIG. 4) is formed between the rollers 76 and 77. The retard roller 76 is provided with a torque limiter 53 (see FIG. 3) that functions when separating the sheets S picked up by the pickup roller 70 one by one.

[Separation conveyance roller pair and its peripheral structure]
Next, the separating and conveying roller pair 78 and its peripheral structure will be described with reference to FIGS. FIG. 3 is a perspective view showing the feeding unit in the manual feeding unit according to the present embodiment, and the pickup roller 70 is not shown. FIG. 4 is a perspective view in which feed introduction guides 54F and 54R as support cover members described later are omitted.

  As shown in FIGS. 3 and 4, the retard roller 76 of the separation conveyance roller pair 78 is supported by a support frame 55 as a support means. The retard roller 76 and the torque limiter 53 are attached to a retard roller shaft 59 that is rotatably supported by the support frame 55. The feed roller 77 facing the retard roller 76 is rotatably supported by the apparatus main body 100a via a support member (not shown).

  In the support frame 55, a separation guide plate 56 and feeding introduction guides 54 </ b> F and 54 </ b> R are attached upstream of the retard roller 76 in the sheet feeding direction D. The separation guide plate 56 is composed of a thin plate (metal plate) made of SUS material (stainless steel) or the like. In the state of FIG. 5 where the upper end surface (guide portion) 56a is exposed and opposed so as to guide the sheet S to the nip portion N, the separation guide plate 56 has a lower end surface (fixed portion) 56c fixed to a fixing screw (fixing means). 27) and is fixed to the support frame 55. Between the upper end surface 56a and the lower end surface 56c, there is provided a bent portion 56b that is bent so that the upper end surface 56a is smoothly curved and positioned from the lower end surface 56c toward the nip portion N. Note that the separation guide plate 56 is not limited to the SUS material, and may be composed of other materials.

  The support frame 55 extends along the axial direction of the separating and conveying roller pair 78, and is provided with a bottom plate portion 55a and upstream bending portions respectively provided on the upstream side and the downstream side in the sheet feeding direction D of the bottom plate portion 55a. Part 55b and downstream bent part 55c. Of the upstream bent portions 55b provided at three locations in the width direction E on the upstream side in the sheet feeding direction D, the upstream bent portion 55b (FIG. 4) in the center portion includes 2 in the width direction E. Screw holes 45d and 45e (see FIGS. 5 and 8) are provided at the locations.

  The separation guide plate 56 has a lower end surface (fixed) in a form in which an upper end surface (guide portion) 56a is positioned so as to guide the sheet S to the nip portion N upstream of the separation conveying roller pair 78 in the sheet feeding direction D. Part) 56c is detachably fixed to the support frame 55. Screw holes 46c and 46d (see FIG. 8) are formed in the separation guide plate 56 along the width direction E of the lower end surface 56c. At the upstream bent portion 55b at the center, the fixing holes 27 are screwed in such a manner that the screw holes 46c and 46d of the separation guide plate 56 face the screw holes 45d and 45e (see FIG. 8). The plate 56 is securely fixed to the upstream bent portion 55b as shown in FIG. In FIG. 4, the illustration of the fixing screw (screw member) 27 on the screw hole 46d side is omitted.

  The separation guide plate 56 fixed to the upstream bent portion 55b as shown in FIG. 4 is covered with the mating portions 60F and 60R which are a part of the feed introduction guides 54F and 54R as shown in FIG. The feeding introduction guides 54F and 54R are a plurality of cover members that cover the lower end surface 56c of the separation guide plate 56 in a state where the mating portions 60F and 60R are in contact with each other in the extending direction of the support frame 55 (end portions). It is. The feeding introduction guides 54F and 54R are detachably fixed to the support frame 55 in such a manner that the lower end surface 56c of the separation guide plate 56 is covered and supported from the upstream side in the sheet feeding direction D.

  The feeding introduction guides 54F and 54R are formed by fitting the fixing screws 25 into the screw holes 54b, 54d and 54f of the locking portions 54a, 54j, 54c and 54e provided in the respective portions in the longitudinal direction. It fixes to the support frame 55 in the state which combined 60F and 60R. In this state, the feed introduction guides 54F and 54R expose the torque limiter 53, the retard roller 76, and the separation guide plate 56 from the notches 54g, 54h, and 54i formed in the vicinity of the mating portions 60F and 60R. .

[Details of feeding section]
Next, a detailed configuration of the feeding unit 23 in the manual feeding unit 2 will be described with reference to FIGS. 4 and 5. FIG. 5 is a cross-sectional view showing the feeding unit 23 in FIG. 3 cut along the front side of the retard arm 58.

  As shown in FIGS. 4 and 5, the retard roller shaft 59 is rotatably supported with respect to the support frame 55 via a frame (not shown), and the retard roller shaft 59 is parallel to the retard roller shaft 59. Similarly, the arm rotation shaft 57 is supported by the support frame 55. A retard arm 58 is fixed to the retard arm rotation shaft 57 in a state in which a shaft insertion hole 58a at the base end thereof is fitted. A shaft insertion hole 58 b formed on the free end side of the retard arm 58 is slidably fitted to the retard roller shaft 59. As described above, the retard arm 58 rotates around the rotation shaft 57 while being supported by the retard arm rotation shaft 57 supported by the support frame 55 via a frame (not shown). A gear 67 is attached to the retard arm rotation shaft 57.

  The retard arm 58 is urged by a retard spring 68 in a direction in which the retard roller 76 is pressed against the feed roller 77. The retard spring 68 is composed of a compression coil spring, and the other end is brought into contact with the support portion 58c of the retard arm 58 with one end thereof being brought into contact with the support portion 43 in the bottom plate portion 55a. In this state, the retard spring 68 pushes up the retard roller shaft 59 via the retard arm 58 to bring the retard roller 76 into contact with the lower portion of the feed roller 77.

  As shown in FIG. 5, when the sheet bundle (S) stacked on the feeding tray 18 receives a force fed by the pickup roller 70, the sheet S is separated by the separation conveying roller pair 78 by the upper end surface 56 a of the separation guide plate 56. Is guided to the nip portion N. As a result, it is possible to prevent a phenomenon in which the leading end of the uppermost sheet S hits the surface of the feed roller 77 or the retard roller 76 on the side away from the nip portion N and is bent or broken.

[Near the nip part of the separation conveying roller pair]
Next, details of the vicinity of the nip portion of the separation conveyance roller pair will be described with reference to FIG. FIG. 6 is an enlarged cross-sectional view showing the nip portion N of the separation conveyance roller pair 78 and its vicinity in an enlarged manner.

  As shown in FIG. 6, the separation guide plate 56 is mounted in a regular shape, and its upper end surface 56 a is positioned in the vicinity of the nip portion N of the separation conveyance roller pair 78 at an appropriate interval. In this state, the separation guide plate 56 formed of a thin plate such as a SUS material can guide the sheet S to the vicinity of the nip portion N.

Here, the interval B between the upper end surface 56a and the feed roller 77 includes a minimum distance that does not cause a conveyance resistance when the uppermost sheet enters the nip portion N, including component tolerance and bearing play. Is set to The distance B is the distance between the closest portions 56a ₁ and the nip line NL of the upper end surface 56a of the perpendicular line P ₁ with respect to the common tangent line at a nip line NL of the feed roller 77 and the retard roller 76 at the nip portion N Indicates.

The distance C between the upper end surface 56a and the retard roller 76 is a minimum distance at which the retard roller 76 and the separation guide plate 56 do not come into contact with each other even when the relative positional relationship changes due to component tolerance, bearing play, or the like. Is set. The distance C represents the distance between the closest portions 56a ₂ and the retard roller 76 surface of the upper end surface 56a of the perpendicular line _{P 2} against the retard roller 76. Specifically, the interval B is preferably set to 1.0 to 2.0 [mm], and the interval C is preferably set to about 1.0 to 1.5 [mm]. It is also possible to set.

[Sheet behavior]
With the configuration described above, the behavior of the sheet will be described below.

  First, the case where the sheet S having a small thickness and low rigidity is fed will be described. That is, the leading edge of the thin sheet S guided to the nip portion N by the upper end surface 56 a of the separation guide plate 56 abuts on the outer peripheral surface of the retard roller 76 that is rotating as the feed roller 77 rotates. Then, the sheet S is drawn into the nip portion N of the separation conveyance roller pair 78 according to the rotation of the feed roller 77. In the nip portion N, the sheets S that have entered a plurality of sheets are separated by the retard roller 76 that rotates in the returning direction with a predetermined torque by the action of the torque limiter 53, and only the uppermost sheet S is fed, and the sheet feeding direction Sent to the downstream side of D.

  Next, a case where the sheet S having a large thickness and high rigidity is fed will be described. That is, the leading end of the thick sheet S guided to the nip portion N by the upper end surface 56 a of the separation guide plate 56 abuts against the outer peripheral surface of the retard roller 76. At this time, since the upper end surface 56a of the separation guide plate 56 is located at a position close to the outer peripheral surface of the feed roller 77, other than the sheet closest to the uppermost sheet S among the plurality of fed sheet bundles is separated. It is blocked by the guide plate 56.

  For this reason, the number of sheet bundles to enter the nip portion N of the separation conveying roller pair 78 is reduced by the separation guide plate 56, the rigidity of the entire sheet bundle that strikes the retard roller 76 is weakened, and further, the retard roller 76. The angle which hits is made small. That is, by bringing the sheet S into contact in a direction closer to the nip line NL of the separation conveyance roller pair 78, the force received from the sheet bundle in the direction in which the retard roller 76 is separated from the feed roller 77 can be greatly reduced. This is an effect obtained by arranging the separation guide plate 56 so that the upper end surface 56a thereof is close to the nip line NL and the nip portion N of the separation conveyance roller pair 78.

  The leading edge of the sheet that has come into contact with the retard roller 76 enters the nip portion N of the separating and conveying roller pair 78 while slightly curving, and the second and subsequent sheets S are separated by the retard roller 76.

  Next, characteristic effects and the like of the present embodiment due to the arrangement and attachment of the separation guide plate 56 and the feeding introduction guides 54F and 54R will be described with reference to FIGS. 7 (a) and 7 (b). 7A and 7B are schematic diagrams illustrating an example of a paper jam process. FIG. 7A shows a comparative example, and FIG. 7B shows this embodiment.

  When a paper jam occurs in any part of the sheet conveyance path of the image forming apparatus 100, the sheet remaining in the nip portion N of the separation conveyance roller pair 78 is gripped by the hand H in the sheet feeding direction D ( Consider a case where the user performs the work of removing by pulling in the direction F opposite to that shown in FIG. At this time, since the force in the direction in which the remaining sheet rolls over the separation guide plate 56 acts on the separation guide plate 56, the separation guide plate 56 is plastically deformed or dropped off as in the comparative example shown in FIG. There is a fear.

  On the other hand, according to the present embodiment shown in FIG. 7B, the attachment portions of the separation guide plate 56 to the support frame 55 are the fitting portions 60F and 60R of the feed introduction guides 54F and 54R (see FIG. 3). Covered with. Therefore, even when the upper end surface 56a is deformed by the sheet S pulled in the direction of arrow F during the paper jam processing, the separation guide plate 56 is firmly supported by the mating portions 60F and 60R with the lower end surface 56c. This prevents the separation guide plate 56 from being plastically deformed or dropped off.

  The separation guide plate 56 is a conveyance guide that guides the sheet S. The separation guide plate 56 is scratched on a portion that guides the sheet S due to the above-described paper jam processing operation or scraping due to repeated (endurance) sheet feeding. There is a risk of sticking. If scratches or dents are formed in this way, it may be a factor that impairs the good conveyance of the sheet S and may cause a feeding failure. Further, the pick-up roller 70 for feeding the sheet S also has a reduction in frictional force due to scraping due to repetition (durability) of sheet feeding and a sheet material component adhering to the roller surface, and a reduction in roller performance due to aging. Etc., which cause a conveyance failure.

  In order to cope with these, in the present embodiment, it is desirable that the separation guide plate 56 and the retard roller (separation roller) 76 can be easily replaced in accordance with the use state of the manual feed unit 2. In the present embodiment, a configuration that facilitates replacement of the separation guide plate 56 and the pickup roller 70 is also considered. 8 is an exploded perspective view showing the feeding introduction guides 54F and 54R removed from the support frame 55. As shown in FIG.

  As shown in FIG. 8, the support frame 55 is provided with an access space (opening) 69, and the retard roller 76 can be removed from the access space 69 when the feed introduction guides 54F and 54R are removed from the support frame 55. It becomes a state. That is, when the feed introduction guides 54F and 54R are removed from the support frame 55, an access space 69 in which the retard roller 76 can be removed from the support frame 55 appears. In this state, the retard roller 76 and the torque limiter 53 can be replaced. Work becomes possible. Since the access space 69 is provided, the retard roller 76 and the torque limiter 53 can be easily removed and replaced from the retard roller shaft 59, and further, the separation guide plate 56 can be removed by removing the fixing screw 27 (FIG. 4). Can also be easily replaced.

  It is also possible to configure so that the contact portions of the mating portions 60F and 60R are positioned on the near side in FIG. In that case, the separation guide plate 56 and the retard roller 76 (only the removal guide plate 56R and the retard roller 76 (in this case, the back side feed introduction guide 54R) are simply removed from the pair of feed introduction guides 54F and 54R. The torque limiter 53) can be easily replaced.

  In the above-described embodiment, the separation guide plate 56 is made of a thin member with low rigidity and has a simple structure as much as possible, while the residual sheet sandwiched between the separation conveyance roller pair 78 is pulled and removed. In addition, the separation guide plate 56 can be prevented from falling off and plastic deformation. Then, by simply removing at least one of the feed introduction guides 54F and 54R from the support frame 55, the separation guide plate 56 can be easily replaced, and the reliability of the feed performance can be maintained.

  In this embodiment, the manual feeding unit 2 has been described as the sheet feeding device of the present invention. However, the present invention is not limited to this, and the sheet feeding unit 36 (see FIG. 1) having the feed roller 37 and the retard roller 38 is used. It is also possible to apply the present invention. In this embodiment, the electrophotographic image forming apparatus 100 has been described. However, instead of this, the present invention is applied to an ink jet type image forming apparatus that forms an image on a sheet by ejecting ink liquid from a nozzle. The invention can also be applied.

2 ... Manual feeding unit (sheet feeding device)
17 Image forming section (image forming means)
18 ... Feed tray (loading means, manual feed tray)
27 ... Fixing screw (fixing means, screw member)
45d, 45e ... screw holes 54F, 54R ... support cover member (feeding introduction guide, cover member)
55 ... Support frame (support means)
56 ... Separation guide plate (metal plate)
56a ... Upper end surface (guide portion)
56c ... Lower end surface (fixed part)
69 ... Access space (opening)
76 ... retard roller (separation roller)
77 ... Feed roller (conveyance roller)
78: Separation conveyance roller pair 100 ... Image forming apparatus 100a ... Image forming apparatus main body D ... Sheet feeding direction (sheet conveyance direction)
N ... Nip part S ... Sheet

Claims (8)

A stacking means on which sheets are stacked;
A conveyance roller and a separation roller for separating and conveying the sheets sent from the stacking unit one by one at a nip portion formed in contact with each other;
Supporting means for supporting the separation roller;
The nip portion has a guide portion for guiding the sheet and a fixing portion fixed to the supporting means, and the fixing portion is detachably fixed to the supporting means upstream of the separation roller in the sheet conveying direction. A separation guide plate;
A support cover member that is detachably fixed to the support means in such a manner that the fixing portion is supported so as to cover from the upstream side in the sheet conveying direction with the guide portion of the separation guide plate exposed. ,
A sheet feeding apparatus characterized by that. The support means is a support frame extending along the axial direction of the separation roller;
The support cover member is composed of a plurality of cover members that cover the fixed portion in a state in which ends thereof are in contact with each other in the extending direction of the support frame.
The sheet feeding apparatus according to claim 1. The support frame is provided with an opening,
When at least one of the plurality of cover members is removed from the support frame, the separation roller can be removed from the opening.
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. The separation guide plate is a metal plate;
The sheet feeding device according to any one of claims 1 to 3, wherein the sheet feeding device is provided. The fixing portion of the separation guide plate is fixed to the support means by a screw member;
The sheet feeding device according to any one of claims 1 to 4, wherein the sheet feeding device is provided. A feeding roller that is arranged upstream of the conveying roller and the separation roller in the sheet conveying direction, and that feeds the sheets stacked on the stacking unit to the nip portion;
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. The sheet feeding device according to any one of claims 1 to 6,
Image forming means for forming an image on a sheet conveyed by the conveyance roller and the separation roller;
An image forming apparatus. The stacking means is a manual feed tray disposed on a side portion of the image forming apparatus main body.
The image forming apparatus according to claim 7.

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