Sheet feeding device and image forming apparatus

Abstract

To provide a sheet feeding device that can as well be applied to manual feeding parts, and makes it easy to replace pickup rollers, and an image forming device.SOLUTION: A sheet feeding device (10) takes in sheet-shaped media placed on a tray (112). A roller holder (20) is provided on the back side of the tray and is rotatable around a rotation shaft (38) on the back side. The roller holder rotatably holds a pickup roller (46). A pre-separation guide (24) is provided below the roller holder. The pre-separation guide is supported rotatably around a front support shaft (52). A contact part (56) is provided in the pre-separation guide, lifts the front side of the roller holder (20), and when the back side of the pre-separation guide (24) is lifted, it hits the roller holder and supports the roller holder.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device and an image forming apparatus, and more particularly to a sheet feeding device and an image forming apparatus in which a sheet is taken into the inside of the image forming apparatus by a soft pickup roller, such as in a manual paper feed section of the image forming apparatus. [Background technology]

[0002] One example of this type of background technology is disclosed in Patent Document 1. In the technology of Patent Document 1, a rotatable support arm is provided on a paper feed cover having a lever, a pickup roller is provided at the tip of the support arm, and the engagement between a first engagement part of the support arm and a second engagement part of the lever is released in conjunction with the operation of the lever. In the released state, the support arm can be rotated to move the pickup roller to a position where it is easy to replace it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-168930 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 has a structure in which a support arm is provided on the feeder cover, and therefore cannot be applied to a manual feeder unit or the like that does not have a feeder cover.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Therefore, a primary object of the present invention is to provide a novel sheet feeding device and image forming apparatus.

[0006] Another object of the present invention is to provide a sheet feeding device and an image forming apparatus which are applicable to a manual paper feed section and which facilitate replacement of the pickup roller. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following configuration. Note that the reference symbols and supplementary explanations in parentheses indicate the corresponding relationships with the embodiments described to aid in understanding the present invention, and do not limit the present invention in any way.

[0008] The first invention is a sheet feeding device that takes in sheet media placed on a tray into an image forming device, comprising: a roller holder provided on the image forming device side of the tray and rotatable around a pivot having an axis perpendicular to the direction in which the sheet media is taken in; a pickup roller held by the roller holder for taking in the sheet media on the tray; a pre-separation guide provided below the roller holder and rotatable on the image forming device side around a support shaft having an axis perpendicular to the direction in which the sheet media is taken in; and a contact portion provided on the pre-separation guide that abuts against an appropriate portion of the roller holder and supports the roller holder when the tray side of the roller holder is lifted and the image forming device side of the pre-separation guide is lifted.

[0009] In the first invention, a sheet feeder (10: a reference symbol illustrating a part corresponding to the embodiment; the same applies below) takes in a sheet medium placed on a tray (112). The sheet feeder (10) is provided on the rear side of the tray, i.e., on the image forming device side of the tray, and includes a roller holder (20) that is rotatable on the tray side about a rotation shaft (38) that is provided on the rear side and has an axis perpendicular to the direction in which the sheet medium is taken in from the tray. The roller holder rotatably holds a pickup roller (46) for taking in the sheet medium on the tray (112). Since the roller holder is supported by the rotation shaft (38) provided on the rear side, the front side of the roller holder (the side where the pickup roller is provided), i.e., the tray side, can be lifted. A pre-separation guide (24) is provided below the roller holder. The pre-separation guide functions as a separation pad that prevents double feeding of sheet media when the pickup roller (46) takes in the sheet media. The pre-separation guide is supported so that the rear side, i.e., the image forming device side, can rotate about a support shaft (52) provided on the front side and having an axis perpendicular to the direction in which the sheet media is taken in from the tray. In other words, because the pre-separation guide is supported by the support shaft (52) on the front side, i.e., the tray side, the rear side of the pre-separation guide, i.e., the image forming device side, can be lifted. The abutment portion (56) is provided on the pre-separation guide, and abuts against the roller holder from below to support the roller holder when the front side, i.e., the tray side, of the roller holder (20) is lifted and the rear side, i.e., the image forming device side, of the pre-separation guide (24) is lifted.

[0010] According to the first aspect of the present invention, the roller holder is supported from below by the pre-separation guide, so that the roller holder can be prevented from descending, and replacement of the pickup roller can be facilitated.

[0011] A second invention is dependent on the first invention, and is a sheet feeding device, in which the roller holder includes a cover that houses the pickup roller, and the contact portion contacts a lower surface of the cover.

[0012] In the second aspect of the invention, the abutment portion (56) abuts against the lower surface of the cover (26) of the roller holder (20), and the pre-separation guide (24) supports the roller holder from below.

[0013] A third invention is dependent on the second invention, and is a sheet feeding device, in which the cover has a side surface, and the contact portion contacts a lower side of the side surface.

[0014] In the third aspect of the invention, the cover (26) abuts against the lower edge (32a) of the side surface portion (32).

[0015] A fourth invention is dependent on the third invention, and is a sheet feeding device including a recess formed on a lower side of the side portion, and the abutment portion abuts against the lower side at the recess.

[0016] In the fourth aspect of the invention, a recess (58) is formed in the lower edge (32a) of the side surface portion (32) of the cover (26), and the abutment portion (56) abuts against the lower edge at the recess.

[0017] According to the fourth invention, by providing a recess, the distance between the contact point where the abutment portion and the lower edge come into contact and the rotation axis of the roller holder is long, so that the roller holder can be lifted high and not much force is required when raising the pre-separation guide.

[0018] A fifth aspect of the present invention is an image forming apparatus including the sheet feeding device according to any one of the first to fourth aspects of the present invention.

[0019] In the fifth aspect of the present invention, an image forming apparatus (100) includes a sheet feeding device (10).

[0020] A sixth invention is according to the fifth invention, and is an image forming apparatus, wherein the sheet feeding device is provided in a manual paper feed section.

[0021] In the sixth aspect of the invention, the image forming apparatus (100) includes a manual paper feed section (110), and the tray (112) is provided in the manual paper feed section. Effect of the Invention

[0022] According to the present invention, it is possible to obtain a sheet feeding device that can be applied to a manual paper feed section and allows easy replacement of the pickup roller.

[0023] The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic view of the sheet feeding device taken out of the image forming apparatus shown in FIG. 1, showing a state (usage state) in which the pre-separation guide is laid down. [Diagram 3] FIG. 3 is an illustrative view showing a state in which the pre-separation guide is raised in the sheet feeding device shown in FIG. 2 (when the pickup roller is replaced, etc.). [Figure 4] FIG. 4 is a diagram showing an operation for replacing the pickup roller in the configuration of the first embodiment, FIG. 4(A) shows a normal use state, and FIG. 4(B) shows a state after replacement. [Diagram 5] FIG. 5 is a diagram showing an operation for replacing the pickup roller in the configuration of the second embodiment, FIG. 5(A) shows the normal use state, and FIG. 5(B) shows the state after replacement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Fig. 1 is a schematic diagram showing an image forming apparatus 100 according to an embodiment of the present invention. The image forming apparatus 100 shown in Fig. 1 includes a main body 102, and an image forming unit (not shown) is provided inside the main body 102.

[0026] An original reading unit 104 is provided at the upper end of main body 102, and includes an original feeding unit 104a. The original fed from this original feeding unit 104a is read by a scanner (not shown), and the read original image is printed on a sheet-like recording medium such as recording paper (hereinafter, these are collectively referred to as "recording sheet" or "sheet-like medium") in an image forming unit.

[0027] An operation unit 106 including a numeric keypad and a touch panel is provided in front of (on the front side of) the document reading unit 104. The operation unit 106 is used to set a job to be executed (copy, print, facsimile, etc.) and to set conditions for printing an image in the image forming unit (for example, the number of copies to be printed, single-sided / double-sided, etc.).

[0028] A plurality of paper feed cassettes 108 are provided at the bottom of the main body 102 so as to be insertable / removable for each size of recording sheets, as is well known.

[0029] In addition to the automatic paper feed from these paper feed cassettes 108, a manual paper feed section 110 for manually feeding recording sheets is provided on a side surface of the main body 102 (the right side surface in this embodiment).

[0030] The manual paper feed unit 110 includes a sheet feed unit 10 that takes in recording sheets from a paper feed tray 112 on which recording sheets to be fed are placed. When recording sheets are piled up and placed on the paper feed tray 112, the sheet feed unit 10 takes them into the main body 102 in order starting from the topmost recording sheet.

[0031] 2 and 3 are views showing the sheet feeding section 10 taken out from the main body 102 (FIG. 1), but for ease of illustration, the left and right are reversed from FIG. 1.

[0032] In addition, pre-separation guide 24, which functions as a separation pad and will be described later, is arranged to be able to rise and fall in the direction of arrow A. FIG. 2 shows the normal use state in which pre-separation guide 24 is laid down, while FIG. 3 shows the state in which pre-separation guide 24 is raised forward, for example, when replacing the pickup roller.

[0033] The sheet feeding unit 10 includes a case 12 made of synthetic resin that holds the entire structure, and this case 12 is removably attached to the back of a paper feed tray 112 on the side of the main body 102 shown in Fig. 1 by left and right attachment parts 14. A connecting part 16 is provided on the lower front part of the case 12. The base end of the paper feed tray 112 shown in Fig. 1 is integrally connected to this connecting part 16.

[0034] An opening 18 for mounting the roller assembly 20 is formed in the front surface of the case 12, and the left and right inner walls of the opening 18 function as a holding frame 22 for mounting the roller assembly 20. In other words, a bearing (not shown) is provided in the inner wall of the opening 18, and the bearing supports a rotation shaft 38 (described below) of the roller assembly 20 so that the roller assembly 20 can rotate in the direction of the arrow B (B1 or B2).

[0035] The above-mentioned pre-separation guide 24 is provided at a position corresponding to the opening 18 of the connecting portion 16. The pre-separation guide 24 prevents overlapping recording sheets from being taken in when the sheet feeding portion 10 takes in the recording sheets from the paper feed tray 112. As described above, the pre-separation guide 24 is supported by the connecting portion 16 so as to be rotatable in the direction of the arrow A (A1 or A2).

[0036] 4, the sheet feeding section 10 of this embodiment is configured by a combination of main parts, namely, a roller assembly 20 and a pre-separation guide 24 below it, both of which are provided at the rear side of the paper feed tray 112, i.e., on the image forming apparatus 100 side of the paper feed tray 112. In the following description, the term "rear side" refers to the image forming apparatus 100 side, and the term "front side" refers to the paper feed tray 112 side.

[0037] First, the roller assembly 20 includes a pickup roller 46, a feed roller 42, a drive transmission mechanism (not shown), and a cover 26 made of synthetic resin. The cover 26 includes a flat portion 28, a curved portion 30 formed at the tip of the flat portion 28, and a side portion 32 connecting the flat portion 28 and the curved portion 30. A through hole 34 is formed at a predetermined position of the side portion 32.

[0038] Furthermore, a lever 36 that protrudes forward is formed at the tip of the side portion 32 and the curved portion 30. This lever 36 serves as a handle for rotating the roller assembly 20 as a whole in the direction of the arrow B (B1 or B2).

[0039] It should be noted that a side portion is also formed on the opposite side to the side portion 32 visible in Fig. 4. This opposite side portion is not shown, but may be referred to by the same reference number "32."

[0040] At the base end of the cover 26, a rotating shaft 38 is formed integrally with the side surface portion 32, protruding outward from the side surface portion 34 (on both sides). This rotating shaft 38 has an axis in a direction perpendicular to the direction in which the sheets are taken in from the paper feed tray 112, and is supported by a bearing (not shown) formed in the holding frame 22 on the inner wall of the opening 18 (FIGS. 2 and 3). Therefore, as described above, the roller assembly 20 is attached in the opening 18 so as to be rotatable in the direction of the arrow B1 or B2 about the rotating shaft 38. In other words, the front side of the roller assembly 20 can be lifted about the rotating shaft 38.

[0041] The rotating shaft 38 is a hollow shaft, and a roller shaft 40 is inserted through the hollow portion. The roller shaft 40 supports a feed roller 42 so as to be rotatable.

[0042] Furthermore, at a position covered by curved portion 30 at the tip of cover 26, roller shaft 44 is fixedly supported by the aforementioned through hole 34. This roller shaft 44 rotatably supports pickup roller 46. Note that the inner shape of through hole 34 and the outer shape of roller shaft 44 are not perfect circles but are irregular in shape with a portion of a circular arc cut out, thereby preventing roller shaft 44 from rotating following the rotation.

[0043] In this way, it can be seen that the roller assembly 20, i.e., the cover 26, functions as a roller holder because it holds the feed roller 42 and the pick-up roller 46. However, it is sufficient for the roller holder to hold at least the pick-up roller 46.

[0044] As is well known, the pickup roller 46 is a roller for picking up recording sheets (not shown) placed or piled up on the paper feed tray 112. To this end, the pickup roller 46 is made up of a hard core and a soft outer layer, and the soft outer layer picks up the recording sheets by friction.

[0045] The feed roller 42 and the pickup roller 46 are connected by a timing belt (not shown) inside the cover 28, and the two are rotated synchronously. This allows the recording sheet to be stably taken in without bending or the like.

[0046] When the outer layer of the pickup roller 46 becomes worn, the pickup roller 46 is no longer able to pick up recording sheets, and the entire pickup roller 46 must be replaced with a new one.

[0047] This embodiment is directed to such a special configuration for cooperating with the pre-separation guide 24 when replacing the pick-up roller 46.

[0048] The pre-separation guide 24, which constitutes the sheet feeding section 10 together with the roller assembly 20, includes a main body 48 made of synthetic resin and shaped like a sled, and sled-shaped side sections 50 are formed on both sides of the main body 48. A support shaft 52 is formed at the tip (front end) of the sled shape of the side section 50. The support shaft 52 mounts the pre-separation guide 24 to the center of the connecting section 16 (FIGS. 2 and 3). The pre-separation guide 24 can be raised and lowered (rotated) in the direction of arrow A (A1 or A2) around the support shaft 52. In other words, the pre-separation guide 24 can lift the front side, i.e., the paper feed tray 112 (FIG. 1) side, around the support shaft 52. Like the rotation shaft of the roller assembly 20, the support shaft 52 also has an axis perpendicular (vertical) to the direction in which the sheets are taken in from the paper feed tray 112.

[0049] The body 48 of the pre-separation guide 24 is formed with an inclined surface that rises toward the back side, and a Mylar sheet 54 is attached to the inclined surface and is similarly inclined so as to rise toward the back side. However, as is well known, this Mylar sheet 54 is a film sheet made of synthetic resin and has flexibility, heat resistance, and insulating properties. The entire back surface of the Mylar sheet 54 is not attached to the inclined surface, but as shown in the figure, for example, only about half of the front side is supported by the inclined surface. Therefore, there is no inclined surface (support part) on the underside of the tip side (rear side), and it is free to swing. In other words, the bending of the tip of this Mylar sheet 54 effectively prevents double feeding of recording sheets.

[0050] The rear end of one side surface portion 50 of the pre-separation guide 24 (the right side surface portion in this embodiment) is formed as a contact portion 56 having a shape that descends toward the rear side.

[0051] In the normal use state shown in Fig. 4(A), the pre-separation guide 24 remains in a face-down position, as also shown in Fig. 2. Note that in Fig. 4(A), the roller assembly 20 is shown in a lifted state, but this is for the purpose of illustrating the pre-separation guide 24 etc. as a whole, and it should be understood that in the actual use state, the roller assembly 20 is rotated in the direction of arrow B2 and is in a lower position than in Fig. 4(A).

[0052] Therefore, the recording sheets on the paper feed tray 112 are picked up (taken in) by the pickup roller 46 and fed into the main body 102 by the feed roller 42. At this time, the pre-separation guide 24 prevents double feeding of the recording sheets, as described above.

[0053] When replacing the pickup roller 46, as shown in Fig. 4(B), the user or service person holds the lever 36 and lifts the roller assembly 20 in the direction of the arrow B1 while raising the pre-separation guide 24 in the direction of the arrow A1. This causes the abutment portion 56 of the pre-separation guide 24 to abut against the lower side 32a of the side surface portion 32 of the cover 26. As a result, the roller assembly 20 is supported from below by the pre-separation guide 24, and even if the lever 36 is released, the roller assembly 20 is prevented from descending. This allows the user or service person to replace the pickup roller 46 using both hands.

[0054] The specific method for replacing the pickup roller 46 is to, while preventing the roller assembly 20 from descending with the pre-separation guide 24 raised as described above, push the roller shaft 44 of the pickup roller 46 from the side portion 32 of the cover 26, thereby removing it from the through hole 34 of the side portion 32. At that time, the roller shaft 44 is also removed from the pickup roller 46, and only the pickup roller 46 can be removed.

[0055] To install a new pickup roller 46, the roller shaft 44 is inserted into the new pickup roller 46 and then fitted into the through hole 34.

[0056] Next, a second embodiment will be described with reference to Fig. 5. However, only the differences from the first embodiment shown in Fig. 4 will be described below.

[0057] In the first embodiment shown in Figure 4, the lower edge 32a of the side portion 32 of the cover 26 of the roller assembly 20 was straight, but in the second embodiment, a recess 58 is formed in the lower edge 32a of the side portion 32.

[0058] When the recess 58 is formed in the lower side 32a in this manner, when the roller assembly 20 is lifted in the direction of the arrow B1 and the pre-separation guide 24 is raised in the direction of the arrow A1 as shown in FIG. 5(B) to replace the pickup roller 46, the location where the abutment portion 56 at the rear end of the side surface portion 50 of the pre-separation guide 24 abuts against the lower side 32a of the side surface portion 32 becomes farther away from the rotation shaft 38 of the roller assembly 20 than in the first embodiment of FIG. 4. In the first embodiment of FIG. 4, in order to support the roller assembly 20 by the pre-separation guide 24, when the pre-separation guide 24 is raised in the direction of the arrow A1, the distance between the contact point between the abutment portion 56 and the lower edge 32a and the rotation axis 38 of the roller assembly 20 is short, so that a relatively large force is required to raise the pre-separation guide 24.

[0059] 5, the distance between the contact point between the abutment portion 56 and the lower side 32a, i.e., the recess 58, and the rotation shaft 38 of the roller assembly 20 is large, so that the roller assembly 20 can be lifted up significantly. Moreover, since the distance between the contact point between the abutment portion 56 and the recess 58 and the rotation shaft 38 is large, a large force is not required when raising the pre-separation guide 24.

[0060] In all of these embodiments, when the pre-separation guide 24 is raised, each part of the pre-separation guide 24, such as the Mylar sheet 54, is arranged so that it does not come into contact with the roller assembly 20. As long as this condition is met, the present invention is not limited to the above-mentioned embodiments.

[0061] In all of the above-mentioned embodiments, the abutment portion 56 formed on the pre-separation guide 24 comes into contact with the lower side 32a (including the recess 58) of the side surface portion 32 of the cover 26 of the roller assembly 20, thereby supporting the roller assembly 20 with the front side of the pre-separation guide 24 raised. In other words, the abutment portion 56 abuts against the lower surface of the cover 28 of the roller holder, thereby supporting the roller holder from below.

[0062] However, the part of the roller holder that the abutment part 56 abuts on is not limited to the lower side 32a of the side surface part 32, but may be, for example, a protrusion (not shown) that protrudes outward from the side surface part 32 and the abutment part 56 may abut on that protrusion. In other words, the abutment part 56 can support the roller holder by coming into contact with an appropriate part of the roller holder.

[0063] Furthermore, the contact portion 56 provided on the pre-separation guide 24 is made to contact the roller assembly 20, i.e., the roller holder, but the position and shape of the contact portion 56 are not limited to those in the embodiment. The place where the pre-separation guide 24 contacts the roller assembly 20 functions as the contact portion.

[0064] In the above embodiment, the sheet feeding device 10 is used in the manual paper feed section of the image forming apparatus 100 shown in Fig. 1. However, it goes without saying that the present invention can also be applied to the document feeding section 104a of the image forming apparatus 100 shown in Fig. 1. In this case, the document is a sheet-like medium. [Explanation of symbols]

[0065] 10...Sheet feeder 20...Roller assembly (roller holder) 24 ... Pre-separation guide 26 ... Cover 32…Side part 32a ... bottom edge 38 ... Rotating shaft 40, 44...Roller shaft 42 ... Feed roller 46 ... Pickup roller 50...Side part 52...Spindle 56 … Contact part 58 ... Recess 100 ... Image forming device 104a … Document feed section 112 ... Paper feed tray

Claims

1. A sheet feeding device that feeds sheet media placed on a tray into an image forming device, a roller holder provided on the image forming device side of the tray, the roller holder being rotatable about a rotation axis having an axis perpendicular to a direction in which the sheet medium is taken in; a pickup roller held by the roller holder for picking up the sheet medium on the tray; a pre-separation guide that is provided below the roller holder and is rotatable on the image forming apparatus side around a support shaft having an axis perpendicular to a direction in which the sheet medium is taken in; and a sheet feeding device including a contact portion provided on the pre-separation guide, the contact portion contacting an appropriate portion of the roller holder and supporting the roller holder when the tray side of the roller holder is lifted and the image forming device side of the pre-separation guide is lifted.

2. 2. The sheet feeding device according to claim 1, wherein said roller holder includes a cover for housing said pickup roller, and said abutting portion abuts against a lower surface of said cover.

3. 3. The sheet feeding device according to claim 2, wherein said cover has a side surface, and said abutment portion abuts against a lower side of said side surface.

4. 4. The sheet feeding device according to claim 3, further comprising a recess formed in a lower side of said side surface portion, said abutting portion abutting against said lower side at said recess.

5. 5. An image forming apparatus comprising the sheet feeding device according to claim 1.

6. 6. The image forming apparatus according to claim 5, wherein the sheet feeding device is provided in a manual paper feed section.

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