JP5325758B2 - Sheet supply apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet supply apparatus that supplies a sheet into an apparatus main body of an image forming apparatus, and an image forming apparatus that includes the apparatus main body and the sheet supply apparatus.

  2. Description of the Related Art Image forming apparatuses such as copiers, printers, and facsimiles include an apparatus main body that includes an image forming unit that forms an image on a sheet such as paper. In addition to the sheet supply cassette provided inside the apparatus main body, the image forming apparatus also has a sheet supply tray (“manual feed tray”) on which sheets supplied to the inside of the apparatus main body are placed outside the apparatus main body. Often called).

  The sheet supply tray constitutes a sheet supply apparatus together with a sheet supply roller, a lift member, a lift cam, and the like (see, for example, Patent Document 1). In the sheet supply apparatus described in Patent Document 1, the sheet supply roller rotates while being in contact with the sheet placed on the sheet supply tray, thereby supplying the sheet into the apparatus main body. The lift member is a member that abuts the sheet against the supply roller by rotating from the sheet supply tray toward the supply roller, and is urged to rotate toward the sheet supply roller and pressed. Has a surface.

  The lift cam is a cam that rotates the lift member in the direction away from the sheet supply roller by pressing the pressed surface of the lift member in the direction away from the sheet supply roller with the cam surface. The lift cam rotates so that the lift member is brought into contact with the sheet supply roller when the sheet placed on the sheet supply tray comes into contact with the sheet supply roller, and the sheet placed on the sheet supply tray is separated from the sheet supply roller. It is rotated so that it can be changed to a separated state.

  According to the sheet supply apparatus described in Patent Document 1, the lift member is rotated so as to be changed to the contact state by rotating the lift cam. As a result, the sheet is sandwiched between the sheet supply roller and the lift member. Then, by rotating the sheet supply roller in this state, the sheet is fed out and supplied to the inside of the apparatus main body.

JP 2006-240859 A

  However, in the sheet supply apparatus described in Patent Document 1, no special contrivance has been made with respect to stably bringing the lift member toward the sheet supply roller. For this reason, when the sheet comes into contact with the sheet supply roller, the sheet tends to move or a large contact noise is likely to occur.

The present invention provides a lift member that contacts a sheet supply roller by rotating from the sheet supply tray toward the sheet supply roller, and a cam surface in a direction of separating the pressed surface of the lift member from the sheet supply roller. And a lift cam that rotates the lift member in a direction away from the sheet supply roller, so that the lift member can be stably approached toward the sheet supply roller. An object of the present invention is to provide a sheet supply apparatus that can suppress the movement of a sheet or the generation of a large contact sound when the sheet contacts a sheet supply roller.
Another object of the present invention is to provide an image forming apparatus including the apparatus main body and the sheet supply apparatus.

  The present invention is arranged outside the apparatus main body of the image forming apparatus and abuts against a sheet supply tray on which a sheet supplied to the inside of the apparatus main body is placed, and a sheet placed on the sheet supply tray A sheet supply roller that supplies the sheet to the inside of the apparatus main body by rotating in a state, and a lift member that contacts the supply roller by rotating from the sheet supply tray toward the supply roller. The lift member is urged to rotate toward the sheet supply roller, and has a lift member having a pressed surface and a cam surface, and the pressed surface of the lift member is placed on the sheet by the cam surface. A lift cam that rotates the lift member in a direction away from the sheet supply roller by pressing in a direction away from the supply roller. By doing so, the lift member is separated from the contact state where the sheet placed on the sheet supply tray comes into contact with the sheet supply roller, and the sheet placed on the sheet supply tray is separated from the sheet supply roller. A lift cam that can be rotated to change to a state, and the lift cam and the lift member have a substantially constant angular velocity when the lift cam rotates at a constant angular velocity. The present invention relates to a sheet feeding device configured to rotate.

  In the process in which the lift cam rotates from the position where the lift member is farthest from the peripheral surface of the sheet supply roller until the lift member contacts the peripheral surface of the sheet supply roller via the sheet, The cam surface preferably presses the pressed surface.

  Further, the lift member has a sheet placement surface on which a sheet is placed, and the pressed surface is located with respect to the sheet placement surface when viewed in the direction of the rotation axis of the lift member. A first pressed surface that extends substantially in parallel, and a second pressed surface that is positioned downstream of the first pressed surface in the sheet supply direction and is inclined so as to approach the sheet placement surface. The lift member preferably rotates so that the second pressed surface is pressed by the cam surface of the lift cam so as to approach or separate from the sheet supply roller.

  The cam surface preferably has a substantially involute curve shape when viewed in the direction of the rotation axis of the lift cam.

  In the state where the lift member is in contact with the peripheral surface of the sheet supply roller via the sheet, the lift cam is preferably configured to be separated from the pressed surface.

  Further, it is preferable that the lift member has a high friction portion having a friction coefficient larger than that of the peripheral surface at a position facing the peripheral surface of the sheet supply roller.

  Further, it is preferable that the sheet supply roller is provided substantially immovably in a direction approaching and separating from the lift member.

  The present invention also relates to an image forming apparatus comprising: an apparatus main body having an image forming unit therein; and the sheet supply apparatus disposed outside the apparatus main body.

According to the sheet supply device of the present invention, the lift member that contacts the supply roller by rotating from the sheet supply tray toward the supply roller, and the pressed surface of the lift member on the cam surface from the sheet supply roller. In a sheet supply apparatus comprising: a lift cam that rotates the lift member in a direction away from the sheet supply roller by pressing in the separation direction, the lift member is stably approached toward the sheet supply roller Therefore, it is possible to provide a sheet supply apparatus that can suppress the movement of the sheet and the generation of a large contact sound when the sheet comes into contact with the sheet supply roller.
According to the image forming apparatus of the present invention, it is possible to provide an image forming apparatus including the apparatus main body and the sheet supply apparatus.

1 is a front view for explaining an overall structure of a printer 1 as an embodiment of an image forming apparatus of the present invention. FIG. 6 is a perspective view of the manual sheet feeding unit 64 as viewed from the left front side of the apparatus main body M to the right back side in a state where the paper insertion port 601 of the printer 1 is opened. 4 is an enlarged perspective view of a manual sheet feeding unit 64 in a state where a left wall surface ML of the apparatus main body M is removed. FIG. FIG. 6 is an enlarged perspective view of the manual sheet feeder 64 as viewed from the right front side to the left back side. 6 is an enlarged vertical sectional view of an initial state showing a paper feed roller 66, a lift member 610, a lift cam 620, and the like. FIG. The main part showing the first operation state of the operation of the lift member 610, the paper supply roller 66, the lift cam 620, etc. when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper supply roller 66. It is an enlarged vertical sectional view. The main part showing the second operation state of the operation of the lift member 610, the paper supply roller 66, the lift cam 620, etc. when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper supply roller 66. It is an enlarged vertical sectional view. The main part showing the third operation state of the operations of the lift member 610, the paper feed roller 66, the lift cam 620, etc. when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper feed roller 66. It is an enlarged vertical sectional view. The main part showing the fourth operation state of the operations of the lift member 610, the paper feed roller 66, the lift cam 620, etc. when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper feed roller 66. It is an enlarged vertical sectional view. The main part showing the fifth operation state of the operation of the lift member 610, the paper feed roller 66, the lift cam 620, etc. when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper feed roller 66. It is an enlarged vertical sectional view. The locus of the contact point between the cam surface 621 and the pressed surface 612 accompanying the rotation of the lift cam 620 at a constant angular velocity and the axis of the rotating shaft 614 along with the rotation of the lift cam 620 at a constant angular velocity. It is a figure which shows typically the locus | trajectory of the positional change of the approach direction with respect to the paper feed roller 66 in the rotating lift member 610. FIG.

Hereinafter, embodiments of an image forming apparatus of the present invention will be described with reference to the drawings.
The overall structure of a printer 1 as an image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a front view for explaining the overall structure of a printer 1 as an embodiment of an image forming apparatus of the present invention.

  In the following description, as viewed from the user standing on the front side of the printer 1, the left-right direction is the direction of the arrow X, the front-rear (depth) direction is the Y-direction of the arrow, and the up-down direction is the direction of the arrow Z. Since the left-right direction X substantially coincides with the transport direction of the paper T by the manual paper feed unit 64 described later, the transport direction of the paper T may be referred to as the “left-right direction X”.

As shown in FIG. 1, a printer 1 as an image forming apparatus includes an apparatus main body M, an image forming unit GK that forms a predetermined toner image on a sheet T as a sheet based on predetermined image information, and a sheet T. A paper supply / discharge unit KH that supplies paper to the image forming unit GK and discharges the paper T on which the toner image is formed.
The outer shape of the apparatus main body M is configured by a case body BD as a casing.

  As shown in FIG. 1, the image forming unit GK includes photosensitive drums 2a, 2b, 2c, and 2d as image carriers (photosensitive members), charging units 10a, 10b, 10c, and 10d, and a laser as an exposure unit. Scanner units 4a, 4b, 4c, 4d, developing devices 16a, 16b, 16c, 16d, toner cartridges 5a, 5b, 5c, 5d, toner supply units 6a, 6b, 6c, 6d, drum cleaning unit 11a, 11b, 11c, 11d, static eliminators 12a, 12b, 12c, 12d, intermediate transfer belt 7, primary transfer rollers 37a, 37b, 37c, 37d, secondary transfer roller 8, counter roller 18, fixing Part 9.

  As shown in FIG. 1, the paper feed / discharge unit KH includes a paper feed cassette 52, a manual paper feed unit 64 as a sheet supply device, a conveyance path L for paper T, a pair of registration rollers 80, a plurality of rollers or A roller pair and a paper discharge unit 50 are provided. As will be described later, the transport path L is an aggregate of a first transport path L1, a second transport path L2, a third transport path L3, a manual transport path La, and a return transport path Lb.

Hereinafter, each configuration of the image forming unit GK and the paper supply / discharge unit KH will be described in detail.
First, the image forming unit GK will be described.
In the image forming unit GK, charging by the charging units 10a, 10b, 10c, and 10d in order from the upstream side to the downstream side in order along the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d, the laser scanner unit 4a, 4b, 4c, 4d exposure, development devices 16a, 16b, 16c, 16d development, intermediate transfer belt 7 and primary transfer rollers 37a, 37b, 37c, 37d primary transfer, static eliminators 12a, 12b, 12c, 12d Is eliminated, and cleaning is performed by the drum cleaning units 11a, 11b, 11c, and 11d.
Further, in the image forming unit GK, secondary transfer by the intermediate transfer belt 7, the secondary transfer roller 8 and the counter roller 18, and fixing by the fixing unit 9 are performed.

  Each of the photosensitive drums 2a, 2b, 2c, and 2d is formed of a cylindrical member and functions as a photosensitive member or an image carrier. Each of the photosensitive drums 2 a, 2 b, 2 c, and 2 d is disposed so as to be rotatable in the direction of an arrow about an axis that extends in a direction orthogonal to the traveling direction of the intermediate transfer belt 7. An electrostatic latent image can be formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d.

  Each of the charging units 10a, 10b, 10c, and 10d is disposed to face the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the charging units 10a, 10b, 10c, and 10d uniformly charges the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d negatively (minus polarity) or positively (plus polarity).

  The laser scanner units 4a, 4b, 4c, and 4d function as exposure units, and are spaced apart from the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the laser scanner units 4a, 4b, 4c, and 4d includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  Each of the laser scanner units 4a, 4b, 4c, and 4d scans and exposes the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d based on image information input from an external device such as a PC (personal computer). The scanning exposure is performed by each of the laser scanner units 4a, 4b, 4c, and 4d, thereby removing the charges on the exposed portions of the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Thereby, electrostatic latent images are formed on the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  The developing devices 16a, 16b, 16c, and 16d are provided corresponding to the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the developing devices 16a, 16b, 16c, and 16d attaches the toner of each color to the electrostatic latent image formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d, and converts the color toner image into the photosensitive drum. 2a, 2b, 2c and 2d are formed on the respective surfaces. Each of the developing devices 16a, 16b, 16c, and 16d corresponds to four colors of yellow, cyan, magenta, and black. Each of the developing devices 16a, 16b, 16c, and 16d includes a developing roller disposed opposite to the surface of the photosensitive drums 2a, 2b, 2c, and 2d, a stirring roller for stirring the toner, and the like.

  Each of the toner cartridges 5a, 5b, 5c, and 5d is provided corresponding to each of the developing devices 16a, 16b, 16c, and 16d, and each color toner supplied to each of the developing devices 16a, 16b, 16c, and 16d. To accommodate. Each of the toner cartridges 5a, 5b, 5c, and 5d accommodates yellow toner, cyan toner, magenta toner, and black toner.

  The toner supply units 6a, 6b, 6c, and 6d are provided corresponding to the toner cartridges 5a, 5b, 5c, and 5d and the developing devices 16a, 16b, 16c, and 16d, respectively. The toners of the respective colors accommodated in 5d are supplied to the developing devices 16a, 16b, 16c, and 16d, respectively. Each of the toner supply units 6a, 6b, 6c, and 6d and each of the developing devices 16a, 16b, 16c, and 16d are connected by a toner supply path (not shown).

  To the intermediate transfer belt 7, the toner images of the respective colors formed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary-transferred. The intermediate transfer belt 7 is stretched around a driven roller 35, a counter roller 18 including a driving roller, a tension roller 36, and the like. Since the tension roller 36 biases the intermediate transfer belt 7 from the inside to the outside, a predetermined tension is applied to the intermediate transfer belt 7.

  Primary transfer rollers 37a, 37b, 37c, and 37d are arranged to face each other on the side opposite to the photosensitive drums 2a, 2b, 2c, and 2d with the intermediate transfer belt 7 interposed therebetween.

  A predetermined portion of the intermediate transfer belt 7 is sandwiched between the primary transfer rollers 37a, 37b, 37c, and 37d and the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The predetermined portion thus sandwiched is pressed against the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Primary transfer nips N1a, N1b, N1c, and N1d are formed between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d, respectively. In each of the primary transfer nips N1a, N1b, N1c, and N1d, the toner images of the respective colors developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary-transferred onto the intermediate transfer belt 7, respectively. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  To the primary transfer rollers 37a, 37b, 37c, and 37d, toner images of the respective colors formed on the photosensitive drums 2a, 2b, 2c, and 2d are respectively transferred to the intermediate transfer belt 7 by a primary transfer bias applying unit (not shown). A primary transfer bias for transferring the toner image is applied.

  The static eliminators 12a, 12b, 12c, and 12d are arranged to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The static eliminators 12a, 12b, 12c, and 12d respectively irradiate the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d to irradiate light, and the photosensitive drums 2a, 2b, and 2c after the primary transfer is performed. 2d, each surface is neutralized (charge is removed).

  The drum cleaning units 11a, 11b, 11c, and 11d are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Each of the drum cleaning units 11a, 11b, 11c, and 11d removes toner and adhering matter remaining on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and conveys the removed toner to a predetermined recovery mechanism. And collect it.

  The secondary transfer roller 8 secondarily transfers the full-color toner image primarily transferred to the intermediate transfer belt 7 onto the paper T. A secondary transfer bias for transferring the full color toner image formed on the intermediate transfer belt 7 to the paper T is applied to the secondary transfer roller 8 by a secondary transfer bias applying unit (not shown).

  The secondary transfer roller 8 contacts or separates from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is configured to be movable between a contact position where the secondary transfer roller 8 is in contact with the intermediate transfer belt 7 and a spaced position where the secondary transfer roller 8 is separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is disposed at a contact position when the full-color toner image primarily transferred onto the surface of the intermediate transfer belt 7 is secondarily transferred to the paper T, and in other cases. It is arranged at a separated position.

  A counter roller 18 is disposed on the opposite side of the intermediate transfer belt 7 from the secondary transfer roller 8. A predetermined portion of the intermediate transfer belt 7 is sandwiched between the secondary transfer roller 8 and the opposing roller 18. Then, the paper T is pressed against the outer surface of the intermediate transfer belt 7 (the surface on which the toner image is primarily transferred). A secondary transfer nip N <b> 2 is formed between the intermediate transfer belt 7 and the secondary transfer roller 8. In the secondary transfer nip N2, the full-color toner image primarily transferred to the intermediate transfer belt 7 is secondarily transferred to the paper T.

  The fixing unit 9 melts and presses the toner of each color constituting the toner image secondarily transferred onto the paper T and fixes the toner on the paper T. The fixing unit 9 includes a heating rotator 9a heated by a heater and a pressure rotator 9b pressed against the heating rotator 9a. The pressure rotating body 9 b is formed by an endless rotating belt that is stretched between the pressure roller 920 and the tension roller 930. The heating rotator 9a and the pressure rotator 9b sandwich and pressurize the paper T onto which the toner image has been secondarily transferred, and convey the paper T. By transporting the paper T while being sandwiched between the heating rotator 9a and the pressure rotator 9b (fixing nip N9), the toner transferred to the paper T is melted and pressurized. It is fixed on the paper T.

Next, the paper supply / discharge unit KH will be described.
As shown in FIG. 1, a paper feed cassette 52 that stores paper T is disposed below the apparatus main body M. The paper feed cassette 52 is configured to be pulled out from the housing of the apparatus main body M in the horizontal direction. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the end of the paper feed cassette 52 on the paper feed side (the left end in FIG. 1). The cassette paper feeding unit 51 includes a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 81 for feeding the paper T one by one to the transport path L. Is provided.

A manual paper feed unit 64 is provided on the left side surface (left side in FIG. 1) of the apparatus main body M. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 as a sheet supply tray that forms a part of the left side surface of the apparatus main body M in the closed state, and a paper feed roller 66 as a sheet supply roller. The lower end of the manual feed tray 65 is attached to the vicinity of the paper feed roller 66 in the apparatus body M so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The paper feed roller 66 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.
Details of the manual sheet feeder 64 will be described later.

  The conveyance path L for conveying the paper T includes a first conveyance path L1 from the cassette paper feeding unit 51 to the secondary transfer nip N2, a second conveyance path L2 from the secondary transfer nip N2 to the fixing unit 9, and a fixing unit. 9 to the paper discharge unit 50, the manual conveyance path La for joining the paper supplied from the manual paper feed unit 64 to the first conveyance path L1, and the third conveyance path L3 from the downstream side to the upstream side. And a return conveyance path Lb for reversing the sheet conveyed to the side and returning it to the first conveyance path L1.

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the return transport path Lb branches from the third transport path L3.

  In the middle of the first conveyance path L1 (specifically, between the second joining portion P2 and the secondary transfer roller 8), a sheet detection sensor (not shown) for detecting the sheet T, A registration roller pair 80 is arranged to synchronize with skew (oblique sheet feeding) correction and toner image formation in the image forming unit GK. The paper detection sensor is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). The registration roller pair 80 conveys the paper T by performing the above-described skew correction and timing adjustment based on the detection signal information from the paper detection sensor.

  An intermediate roller pair 82 is disposed between the first joining portion P1 and the second joining portion P2 in the first transport path L1. The intermediate roller pair 82 is disposed on the downstream side of the paper feed roller pair 81, sandwiches the paper T conveyed from the paper feed roller pair 81, and conveys it to the registration roller pair 80.

  The return conveyance path Lb is a conveyance path that is provided to make the opposite surface (unprinted surface) opposite to the already printed surface to the intermediate transfer belt 7 when performing duplex printing on the paper T. According to the return transport path Lb, the paper T transported from the first branching section Q1 to the paper discharge section 50 is turned upside down and returned to the first transport path L1 and arranged upstream of the secondary transfer roller 8. It can be conveyed to the upstream side of the pair of registration rollers 80. A predetermined toner image is transferred onto the unprinted surface in the secondary transfer nip N2 on the paper T that is reversed upside down by the return conveyance path Lb.

  A rectifying member 58 is provided in the first branch portion Q1. The rectifying member 58 rectifies the transport direction of the paper T that is carried out of the fixing unit 9 and transports the third transport path L3 from the upstream side toward the downstream side in a direction toward the paper discharge unit 50 and the paper discharge unit 50. The conveyance direction of the paper T that is conveyed from the downstream side toward the upstream side of the third conveyance path L3 is rectified in a direction toward the return conveyance path Lb.

  A paper discharge unit 50 is formed at the end of the third transport path L3. The paper discharge unit 50 is disposed on the upper side of the apparatus main body M. The paper discharge unit 50 opens toward the right side of the apparatus main body M (the right side in FIG. 1). The paper discharge unit 50 discharges the paper T to the outside of the apparatus main body M. The paper discharge unit 50 includes a discharge roller pair 53. According to the discharge roller pair 53, the paper T conveyed from the upstream side to the downstream side in the third conveyance path L3 is discharged to the outside of the apparatus main body M, and the conveyance direction of the paper T is reversed in the paper discharge unit 50. Thus, the paper T can be transported toward the upstream side of the third transport path L3.

On the opening side of the paper discharge unit 50, a paper discharge stacking unit M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T formed with a predetermined toner image and discharged from the paper discharge unit 50 are stacked and stacked.
A paper detection sensor is disposed at a predetermined position on each conveyance path.

Next, the operation of the printer 1 of the present embodiment will be briefly described with reference to FIG.
First, a case where single-sided printing is performed on the paper T stored in the paper feed cassette 52 will be described.
The paper T accommodated in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 61 and the paper feed roller pair 81, and then intermediated via the first joining portion P1 and the first transport path L1. It is conveyed to the registration roller pair 80 by the roller pair 82.
In the registration roller pair 80, skew correction of the paper T and timing adjustment with the toner image are performed.

The paper T discharged from the registration roller pair 80 is introduced between the intermediate transfer belt 7 and the secondary transfer roller 8 (secondary transfer nip N2) via the first conveyance path L1. A toner image is transferred onto the paper T between the intermediate transfer belt 7 and the secondary transfer roller 8.
Thereafter, the paper T is discharged from between the intermediate transfer belt 7 and the secondary transfer roller 8, and is interposed between the heating rotator 9a and the pressure rotator 9b in the fixing unit 9 via the second conveyance path L2. It is introduced into the fixing nip N9. Then, the toner melts at the fixing nip N9 and the toner is fixed on the paper T.

Next, the paper T is transported to the paper discharge unit 50 through the third transport path L3, and is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1 by the discharge roller pair 53.
In this way, single-sided printing of the paper T stored in the paper feed cassette 52 is completed.

  When single-sided printing is performed on the paper T placed on the manual feed tray 65, the paper T placed on the manual feed tray 65 is sent out to the manual feed path La by the paper feed roller 66, and then the first joining portion. It is conveyed to the registration roller pair 80 via P1 and the first conveyance path L1. Subsequent operations are the same as the one-side printing operation of the paper T accommodated in the paper feed cassette 52 described above, and a description thereof will be omitted.

Next, the operation of the printer 1 when performing duplex printing will be described.
In the case of single-sided printing, as described above, the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1, and the printing operation is completed.
On the other hand, when performing double-sided printing, the paper T on which single-sided printing has been performed is reversed from the time of single-sided printing and conveyed again to the registration roller pair 80 via the return conveyance path Lb. Then, double-sided printing is performed on the paper T.

  More specifically, the operation is the same as the above-described single-sided printing operation until the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 by the discharge roller pair 53. Thus, in the case of double-sided printing, in a state where the paper T on which single-sided printing has been performed is held by the discharge roller pair 53, the rotation of the discharge roller pair 53 is stopped and rotated in the reverse direction. When the discharge roller pair 53 is thus rotated in the reverse direction, the paper T held by the discharge roller pair 53 moves in the reverse direction (the direction from the paper discharge unit 50 toward the first branching unit Q1) along the third conveyance path L3. ).

  As described above, when the paper T is transported in the reverse direction on the third transport path L3, the paper T is rectified to the return transport path Lb by the rectifying member 58, and then, via the second junction P2. Then, it joins the first transport path L1. Here, the paper T is turned upside down from the one-side printing.

  Further, the sheet T is subjected to the skew correction or the timing adjustment by the registration roller pair 80 and is introduced between the photosensitive drum 2 and the secondary transfer roller 8 through the first conveyance path L1. Since the unprinted surface of the sheet T passes through the return conveyance path Lb and faces the transfer roller 8, the toner image is transferred to the unprinted surface, and as a result, duplex printing is performed.

Next, with reference to FIGS. 2 to 11, details of the manual sheet feeder 64, which is a characteristic part of the present invention, will be described. In FIGS. 2 to 11, the paper T is not shown.
The manual sheet feeding unit 64 will be described in the order of outline description, specific structure, and operation.

  FIG. 2 is a perspective view of the manual sheet feeding unit 64 as viewed from the left front side of the apparatus main body M to the right back side with the paper insertion slot 601 of the printer 1 opened. FIG. 3 is an enlarged perspective view of the manual sheet feeder 64 in a state where the left wall surface ML of the apparatus main body M is removed. FIG. 4 is an enlarged perspective view of the manual sheet feeder 64 as viewed from the right front side to the left back side. FIG. 5 is an enlarged vertical sectional view of the initial state showing the paper feed roller 66, the lift member 610, the lift cam 620, and the like.

As shown in FIGS. 2 to 5, the manual paper feed unit 64 includes a manual feed tray 65, a paper feed roller 66, a lift member 610, and a lift cam 620.
The manual feed tray 65 is disposed outside the left side of the apparatus main body M (left side in FIG. 1), and is a tray on which the paper T supplied to the inside of the apparatus main body M is placed.

An outline of the manual feed tray 65 will be described.
The manual feed tray 65 is rotatably attached at its lower end to the vicinity of the paper feed roller 66 in the apparatus main body M. The manual feed tray 65 is disposed so as to open and close the paper insertion slot 601 formed in the left wall surface ML of the apparatus main body M by rotation at the lower end thereof. Further, the manual feed tray 65 is disposed so as to constitute a part of the left wall surface portion ML of the apparatus main body M in the closed state. As shown in FIG. 2, a paper T of a size and type different from the paper T set in the paper feed cassette 52 is placed on the manual feed tray 65 with the paper insertion slot 601 opened. A lift member 610 (details will be described later) is disposed on the downstream side of the manual feed tray 65 in the paper supply direction (left-right direction X).

A specific structure of the manual feed tray 65 will be described.
As shown in FIGS. 2 to 4, the manual feed tray 65 includes a first tray body 650 and a second tray body 655. The first tray main body 650 is located on the apparatus main body M side, and forms a first paper placement portion 651 on which the entire first size paper T having a small size (for example, A4, B5, etc.) can be placed. To do. The first sheet placement portion 651 is provided with a stopper member 652 that can stand up or lie down. The stopper member 652 receives the rear end of the first size paper T having a small size (for example, A4, B5, etc.), and the first size paper T is arranged on the first paper placement portion 651. It is configured to be able to stand so as to be placed in a state.
Further, the first tray main body 650 is formed in substantially the same size as the paper insertion opening 601. The first tray body 650 is rotatably provided in the apparatus body M in the direction of arrow A by a support shaft J1 (see FIG. 1) parallel to the front-rear direction Y, and can open and close the paper insertion slot 601. .

  The base end portion 650a of the first tray main body 650 connected to the support shaft J1 is positioned below the vertical direction Z when the first tray main body 650 closes the paper insertion slot 601. 2 and 3, when the first tray main body 650 opens the paper insertion slot 601, the base end portion 650a of the first tray main body 650 is positioned downstream of the paper supply direction (left-right direction X). It is supposed to be. As shown in FIG. 1, the support shaft J <b> 1 and the base end portion 650 a of the first tray main body 650 are positioned slightly on the back side in the left-right direction X at the paper insertion opening 601.

  For this reason, the first tray body 650 is received at the lower portion of the paper insertion opening 601 when the paper insertion opening 601 is opened, and has an angle that allows the paper T to slide into the paper insertion opening 601. It is inclined at. That is, the entire manual feed tray 65 is inclined at an angle that allows the paper T to be slid inside the paper insertion slot 601. Further, the first paper placing portion 651 of the first tray body 650 has a side end (an end portion parallel to the front-rear direction Y) of the first size paper T placed on the first paper placing portion 651. A pair of aligning plates 653 and 653 are provided so as to be close to or separated from each other.

The second tray body 655 is slidably connected to the first tray body 650. Specifically, the second tray main body 655 can change between a first state approaching the apparatus main body M (see FIGS. 2 and 3) and a second state separated from the apparatus main body M (not shown). A tray body 650 is slidably connected to the main body 650. In the second state, the second tray main body 655, together with the first tray main body 650, can place a second paper stack that can place all or part of the second size paper T that is larger than the first size. A portion 656 is formed.
That is, the second tray main body 655 is a movable member that can be slid freely inside the first tray main body 650 and pulled out or pushed in by the user in the left-right direction X.

An outline of the paper feed roller 66 will be described.
The sheet feeding roller 66 rotates with its peripheral surface 66 a in contact with the sheet T placed on the first sheet placing portion 651 or the second sheet placing portion 656 of the manual feed tray 65, so that the sheet T Is a roller (roller) for supplying the inside of the apparatus main body M.

A specific structure of the paper feed roller 66 will be described.
As shown in FIGS. 2 to 4, the paper feed roller 66 has a substantially cylindrical shape, and its axial direction (paper feed drive shaft 661) faces the front-rear direction Y. The paper feed roller 66 is disposed so as to be separated above the first paper placement portion 651 of the manual feed tray 65 and the paper placement surface 611 (described later) of the lift member 610. The paper feed roller 66 is disposed at a substantially central portion in the front-rear direction Y of the first paper placement portion 651 of the manual feed tray 65 and the paper placement surface 611 of the lift member 610. The paper feed roller 66 is fixed to the paper feed drive shaft 661.

As shown in FIG. 3, the paper feed drive shaft 661 is composed of a spline shaft, and one end in the axial direction is connected to a drive motor (not shown) via a drive gear (not shown). Therefore, the paper feed roller 66 is rotated by driving the paper feed drive shaft 661 by the drive motor and the drive gear.
The paper feed roller 66 is provided substantially immovably in a direction approaching and separating from the lift member 610. That is, the paper feed roller 66 is fixed so as not to move substantially in the vertical direction Z (only a slight backlash for realizing the rotation is allowed).

An outline of the lift member 610 will be described.
As shown in FIGS. 2 to 5, the lift member 610 is a member that contacts the paper T with the paper feed roller 66 by rotating from the manual feed tray 65 toward the paper feed roller 66. That is, the lift member 610 is a plate-like member that causes the paper T placed on the manual feed tray 65 to approach or separate from the peripheral surface 66 a of the paper feed roller 66. The lift member 610 is disposed below the paper feed roller 66.

A specific structure of the lift member 610 will be described.
The lift member 610 includes a paper placement surface (sheet placement surface) 611 on which the paper T is placed and a pressed surface 612. As shown in FIGS. 4 and 5, a pair of support brackets 613 are fixed to both ends of the lift member 610 in the front-rear direction Y. The support bracket 613 includes a substantially arcuate (C-shaped) bearing portion 613a at the upstream end in the paper supply direction (left-right direction X). A shaft member (not shown) that forms the rotation shaft 614 is inserted and held in the bearing portion 613a.

  A shaft member forming the rotation shaft 614 is rotatably supported by the apparatus main body M. Accordingly, the lift member 610 can be rotated around the axis of the rotation shaft 614. When the lift member 610 is rotated about the axis of the rotation shaft 614, the paper T placed on the paper placement surface 611 of the lift member 610 contacts the peripheral surface 66 a of the paper feed roller 66. It is possible to change between a contact state and a separated state separated from the peripheral surface 66 a of the paper feed roller 66.

  As shown in FIG. 4, a spring member 615 is disposed below the lift member 610 in a substantially central portion in the front-rear direction Y. The lift member 610 is biased to rotate in a direction approaching the peripheral surface 66 a of the paper feed roller 66 by the extension force (repulsive force) of the spring member 615. The lift member 610 includes a pressed surface 612 (details will be described later) on the rear side in the front-rear direction Y. The lift member 610 rotates in a direction away from the peripheral surface 66 a of the paper feed roller 66 when the pressed surface 612 is pressed by the lift cam 620. Therefore, in a state where the pressed surface 612 is not pressed by the lift cam 620, the lift member 610 approaches the peripheral surface 66 a of the paper supply roller 66.

  As shown in FIGS. 4 and 5, a pressed member 616 is provided at one end of the lift member 610 in the axial direction of the rotation shaft 614 (the rear side in the front-rear direction Y). The pressed surface 612 of the lift member 610 is formed on the upper surface of the pressed member 616. The pressed surface 612 includes a first pressed surface 617 that extends substantially parallel to the paper placement surface 611 when viewed from the axial direction (front-rear direction Y) of the rotation shaft 614 of the lift member 610, and a paper placement. And a second pressed surface 618 that is inclined with respect to the placement surface 611. The second pressed surface 618 is a surface that is located downstream of the first pressed surface 617 in the paper supply direction (left-right direction X), and is inclined so as to gradually approach the paper placement surface 611. The lift member 610 is configured so that the second pressed surface 618 is pressed by the cam surface 621 of the lift cam 620, so that the shaft of the rotation shaft 614 approaches or separates from the peripheral surface 66 a of the paper feed roller 66. Rotate around the mind.

  A high friction portion 619 is provided at a position in the center in the front-rear direction Y of the paper placement surface 611 of the lift member 610 and facing the peripheral surface 66 a of the paper feed roller 66. The high friction portion 619 is formed of a member (for example, cloth, cork, rubber, synthetic resin) having a larger friction coefficient than the peripheral surface 66a of the paper feed roller 66. The high friction portion 619 protrudes upward from the paper placement surface 611.

An outline of the lift cam 620 will be described.
As shown in FIGS. 4 and 5, the lift cam 620 has a cam surface 621. The lift cam 620 presses the pressed surface 612 of the lift member 610 with the cam surface 621 in a direction away from the peripheral surface 66 a of the paper supply roller 66, thereby causing the lift member 610 to move toward the peripheral surface 66 a of the paper supply roller 66. The cam is rotated in a direction away from the cam.

A specific structure of the lift cam 620 will be described.
The lift cam 620 is disposed above the pressed surface 612 of the pressed member 616. The lift cam 620 is fixed to a rotary shaft 622 that is rotatably supported by the apparatus main body M. The rotation shaft 622 is connected to a drive motor (not shown) that rotates the paper feed roller 66 via a drive gear (not shown). Therefore, the cam surface 621 presses the pressed surface 612 of the lift member 610 by rotating the lift cam 620 by driving the rotation shaft 622 by the drive motor and the drive gear. The lift cam 620 moves the lift member 610 in a contact state (state in which the paper T to be fed to the manual feed tray 65 comes into contact with the peripheral surface 66a of the paper feed roller 66) and in a separated state (in the manual feed tray 65). The paper T to be separated from the peripheral surface 66a of the paper feed roller 66).

  The cam surface 621 of the lift cam 620 has a substantially involute curve shape when viewed from the axial direction of the rotation shaft 622 of the lift cam 620. The “substantially involute curve shape” is a shape similar to the involute curve as a whole.

  The cam surface 621 of the lift cam 620 is lifted from the position where the lift member 610 is farthest from the peripheral surface 66a of the paper supply roller 66 until the lift member 610 contacts the peripheral surface 66a of the paper supply roller 66 via the paper T. In the process in which the cam 620 rotates, the pressed surface 612 is pressed. Further, in this process, the lift cam 620 allows the lift member 610 to be separated from the pressed surface 612 from the state in which the lift member 610 is in contact with the peripheral surface 66a of the paper feed roller 66 via the paper T. It is configured. Details of this will be described in the description of the operation described later.

The lift cam 620 and the lift member 610 are configured such that when the lift cam 620 rotates at a constant angular speed, the lift member 610 rotates at a substantially constant angular speed.
“The lift member 610 is rotated at a substantially equal angular speed” means that the lift member 610 is rotated at an angular speed at which it can be considered that the lift member 610 is rotated at the equal angular speed.

  For example, the contact between the cam surface 621 of the lift cam 620 and the pressed surface 612 of the lift member 610 is a contact between a curved surface and a straight surface. Therefore, even if the lift cam 620 rotates at a constant angular speed, the lift member 610 does not always rotate at a constant angular speed, and the angular speed varies within a minute range. Such fluctuation in the minute range of the angular velocity of the lift member 610 suppresses the movement of the paper T and the generation of a large contact sound when the paper T comes into contact with the peripheral surface 66a of the paper feed roller 66. From the viewpoint of the object of the present invention, it is the fluctuation of the allowable range. Therefore, even if there is a fluctuation in the angular velocity within such an allowable range, it is included in “the lift member 610 rotates at a substantially equal angular velocity”.

  Next, with reference to FIGS. 5 to 11, the operation of the manual sheet feeder 64 that is a characteristic part of the printer 1 of the present embodiment will be described. 5 to 10 sequentially show operations of the lift member 610, the paper feed roller 66, the lift cam 620, and the like when the paper T is supplied (transferred) from the manual feed tray 65 and the lift member 610 to the paper feed roller 66. It is an expanded vertical sectional view of the principal part. FIG. 11 shows the locus of the contact point between the cam surface 621 and the pressed surface 612 accompanying the rotation of the lift cam 620 at a constant angular velocity and the rotation shaft 614 along with the rotation of the lift cam 620 at a constant angular velocity. It is a figure which shows typically the locus | trajectory of the positional change of the approach direction with respect to the paper feed roller 66 in the lift member 610 rotating around an axial center.

  After the paper T is placed on the first paper placement portion 651 or the second paper placement portion 656 of the manual feed tray 65 and the paper placement surface 611 of the lift member 610, an operation for starting the operation of the printer 1 is performed. When a predetermined signal is transmitted, the feed roller 66 is rotated integrally with the feed drive shaft 661 by a drive motor and a drive gear (not shown), and the lift cam 620 is integrated with the rotary shaft 622. Rotate at an equiangular speed.

  In the initial rotation state of the lift cam 620, as shown in FIG. 5, the portion of the cam surface 621 of the lift cam 620 having the largest eccentric amount (maximum eccentric cam surface portion) 621 a is the first surface of the pressed surface 612. 1 Touches the pressed surface 617. Therefore, the lift member 610 is pressed in the direction farthest from the peripheral surface 66 a of the paper feed roller 66 against the urging force of the spring member 615. As a result, the paper T placed on the paper placement surface 611 of the lift member 610 is in a separated state in which it is separated from the peripheral surface 66 a of the paper feed roller 66.

  In this state, as shown in FIG. 6, when the lift cam 620 continues to rotate at a constant angular speed in the direction of the arrow, the maximum eccentric cam surface portion 621 a of the cam surface 621 becomes the first pressed surface 617 of the pressed surface 612. The contact state changes from the contact state to the second pressed surface 618. As the contact state of the maximum eccentric cam surface portion 621a of the cam surface 621 with respect to the pressed surface 612 changes, the lift member 610 revolves around the axis of the rotating shaft 614 due to the repulsive force of the spring member 615. Rotate at a substantially equal angular speed so as to approach the peripheral surface 66a of the paper feed roller 66. As a result, the paper T placed on the paper placement surface 611 of the lift member 610 approaches the peripheral surface 66 a of the paper feed roller 66.

  From this state, as shown in FIG. 7, when the lift cam 620 continues to rotate in the direction of the arrow at a constant angular velocity, the maximum eccentric cam surface portion 621a of the cam surface 621 becomes the second pressed surface of the pressed surface 612. The state in contact with 618 is maintained. In this state, the lift member 610 rotates at a substantially constant angular speed so as to approach the peripheral surface 66a of the paper feed roller 66 around the axis of the rotation shaft 614 by the repulsive force of the spring member 615. Move. As a result, the paper T placed on the paper placement surface 611 of the lift member 610 is brought into contact with the peripheral surface 66 a of the paper feed roller 66. The sheet T is supplied to the inside of the apparatus main body M by rotating the sheet feeding roller 66 in a state where the sheet T is in contact. Specifically, the paper T is sent out to the manual feed path La, and is then transported to the registration roller pair 80 via the first joining portion P1 and the first transport path L1.

  Thereafter, as shown in FIG. 8, when the lift cam 620 continues to rotate in the direction of the arrow at a constant angular velocity, the portion of the cam surface 621 having the smallest eccentricity (minimum eccentric cam surface portion) 621 b It will be in the state spaced apart upward. In this state, the lift member 610 is in a contact state (a state where the paper T placed on the paper placement surface 611 of the lift member 610 contacts the peripheral surface 66 a of the paper feed roller 66 due to the repulsive force of the spring member 615. ). Accordingly, the supply of the paper T to the inside of the apparatus main body M is continued.

  Further, as shown in FIGS. 9 and 10, when the lift cam 620 continues to rotate at a constant angular velocity, the amount of eccentricity from the minimum eccentric cam surface portion 621b of the cam surface 621 to the maximum eccentric cam surface portion 621a. The gradually increasing portion (gradually increasing eccentric cam surface portion) 621c successively contacts the first pressed surface 617 of the pressed surface 612. As a result, the lift member 610 is in a contact state (the state immediately before the paper T is completely supplied into the apparatus main body M in the state shown in FIG. 9. The lift member 610 is placed on the paper placement surface 611 of the lift member 610. 10 is a separated state (a state where the sheet T is separated from the peripheral surface 66a of the paper feed roller 66 against the urging force of the spring member 615). Changed to

  Thereafter, one rotation (one cycle) of the lift cam 620 at an equal angular speed is completed, and the first paper placement portion 651 or the second paper placement portion 656 of the manual feed tray 65 and the paper placement surface 611 of the lift member 610. Until the next sheet T is placed on the lift member 610, the first pressed surface 617 of the pressed surface 612 is pressed against the cam surface 621 of the lift cam 620 and held in the initial state shown in FIG. Is done.

  FIG. 11 shows the cam surface 621 and the pressed surface 612 accompanying the rotation of the lift cam 620 at a constant angular velocity with respect to the operations of the lift member 610, the paper feed roller 66, the lift cam 620, etc. shown in FIGS. And the locus of the position change in the approaching direction with respect to the sheet feeding roller 66 in the lift member 610 that rotates around the axis of the rotation shaft 614 as the lift cam 620 rotates at a constant angular velocity. Is schematically shown.

According to the manual sheet feeder 64 of the present embodiment, for example, the following effects are achieved.
In the manual paper feed unit 64 of the present embodiment, the paper T is supplied to the inside of the apparatus main body M by rotating in a state where it is in contact with the manual tray 65 and the paper T placed on the manual tray 65. A paper roller 66 and a lift member 610 that abuts the paper T against the paper supply roller 66 by rotating from the manual feed tray 65 toward the paper supply roller 66 so as to rotate toward the paper supply roller 66. The lift member 610 having the pressed surface 612 and the cam surface 621 press the pressed surface 612 of the lift member 610 in a direction away from the paper feed roller 66, thereby supplying the lift member 610. A lift cam 620 that rotates in a direction away from the paper roller 66, and the lift cam 620 rotates so that the lift member 610 is placed on the manual feed tray 65. A lift cam 620 that rotates in a changeable manner between a contact state in which the paper T is brought into contact with the paper feed roller 66 and a separated state in which the paper T placed on the manual feed tray 65 is separated from the paper feed roller 66. The lift cam 620 and the lift member 610 are configured such that when the lift cam 620 rotates at a constant angular speed, the lift member 610 rotates at a substantially constant angular speed.

  Therefore, according to the manual sheet feeding unit 64 of this embodiment, the lift cam 620 is rotated at an equal angular speed, so that the lift member 610 is substantially equal in the direction toward and away from the sheet feeding roller 66. It can be rotated at an angular velocity. Thus, during manual paper feeding, the paper T placed on the lift member 610 can be stably approached toward the paper feeding roller 66 at a substantially constant speed.

Therefore, according to the manual paper feed unit 64 of the present embodiment, the impact when the paper T is brought into contact with the peripheral surface 66a of the paper feed roller 66 is very small, and the paper T moves or generates a loud contact sound. Can be suppressed.
In addition, it is possible to suppress changes in the sheet feeding behavior between the number of sheets T set (placed) on the manual feed tray 65 and between the bottom sheet T and the top sheet T.

  In the manual paper feed unit 64 of the present embodiment, the lift member 610 contacts the peripheral surface 66a of the paper feed roller 66 through the paper T from the position where the lift member 610 is farthest from the peripheral surface 66a of the paper feed roller 66. In the process in which the lift cam 620 rotates, the cam surface 621 is configured to press the pressed surface 612.

  Therefore, according to the manual sheet feeding portion 64 of the present embodiment, even if there is a variation in the biasing force by the spring member 615, for example, the lift member 610 is located from the position that is farthest from the peripheral surface 66a of the sheet feeding roller 66. The rotational angular velocity of the lift member 610 until it contacts the peripheral surface 66a of the paper supply roller 66 can be kept substantially constant. Therefore, the approach of the paper T to the paper feed roller 66 can be further stabilized.

  In the manual paper feed unit 64 of this embodiment, the lift member 610 has a paper placement surface 611 on which the paper T is placed, and the pressed surface 612 is in the direction of the rotation shaft 614 of the lift member 610. When viewed, a first pressed surface 617 that extends substantially parallel to the paper placement surface 611, and is located downstream of the first pressed surface 617 in the paper T supply direction and the paper placement surface 611. The lift member 610 has a second pressed surface 618 that is inclined so as to be closer to the lift member 610, and the second pressed surface 618 is pressed by the cam surface 621 of the lift cam 620. It rotates so that it may approach or separate from.

  Therefore, according to the manual paper feed unit 64 of this embodiment, the paper T is fed into the paper feed roller without abruptly changing the contact state between the pressed surface 612 of the lift member 610 and the cam surface 621 of the lift cam 620. 66 can be brought into contact. Therefore, the approach of the paper T to the paper feed roller 66 can be further stabilized.

In the manual paper feed unit 64 of the present embodiment, the lift cam 620 can be separated from the pressed surface 612 in a state where the lift member 610 is in contact with the peripheral surface 66a of the paper feed roller 66 via the paper T. It is configured.
Therefore, according to the manual paper feed unit 64 of the present embodiment, after the paper T comes into contact with the peripheral surface 66a of the paper feed roller 66, the contact state is maintained by the repulsive force of the spring member 615. Therefore, the contact state can be stably maintained. Therefore, the paper T can be reliably and stably supplied to the inside of the apparatus main body M by the paper supply roller 66.

Further, in the manual sheet feed portion 64 of the present embodiment, the lift member 610 has a high friction portion 619 having a friction coefficient larger than that of the peripheral surface 66 a at a position facing the peripheral surface 66 a of the paper supply roller 66.
Therefore, according to the manual sheet feeding unit 64 of the present embodiment, the lower surface of the sheet T is brought into contact with the high friction unit 619 having a large friction coefficient in a state where the sheet T is in contact with the peripheral surface 66a of the sheet feeding roller 66. It can be supported in a non-slip state. Therefore, the supply of the paper T to the inside of the apparatus main body M by the paper supply roller 66 can be performed more reliably and stably.

Further, in the manual paper feed unit 64 of the present embodiment, the paper feed roller 66 is provided substantially immovably in a direction approaching and separating from the lift member 610. That is, the paper feed roller 66 is configured to rotate at a fixed position.
Therefore, according to the manual sheet feeding portion 64 of the present embodiment, the structure is simple and the assembly of the apparatus is easier than the case where the sheet feeding roller 66 itself is moved in a direction approaching and separating from the lift member 610. Is also easy.

As mentioned above, although preferred embodiment of this invention was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
For example, in the above-described embodiment, a color printer is described as the image forming apparatus. However, the present invention is not limited to this, and may be a monochrome printer, a copier, a facsimile, or a complex machine thereof.
Examples of the sheet include paper and film sheets.

  DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 64 ... Manual feed part (sheet supply apparatus), 65 ... Manual feed tray (sheet supply tray), 66 ... Paper feed roller (sheet supply roller), 66a ... Circumferential surface of paper feed roller (Surrounding surface of sheet supply roller), 610... Lift member, 611... Paper placement surface (sheet placement surface), 612 .. pressed surface, 614 .. rotating shaft, 617 .. first pressed surface, 618. 2 pressed surface, 619 ... high friction part, 620 ... lift cam, 621 ... cam surface, 622 ... rotating shaft, M ... apparatus main body, T ... paper (sheet)

Claims (6)

A sheet supply tray disposed outside the apparatus main body of the image forming apparatus and on which sheets to be supplied to the inside of the apparatus main body are placed;
A sheet supply roller that supplies the sheet to the inside of the apparatus main body by rotating in contact with the sheet placed on the sheet supply tray;
A lift member that contacts the sheet supply roller by rotating from the sheet supply tray toward the sheet supply roller, and is biased to rotate toward the sheet supply roller; A lift member having a pressed surface;
A lift that has a cam surface and rotates the lift member in a direction away from the sheet supply roller by pressing the pressed surface of the lift member in a direction away from the sheet supply roller. The lift cam rotates so that the lift member is placed on the sheet supply tray in a contact state where the sheet placed on the sheet supply tray abuts on the sheet supply roller. A lift cam that can be changed to a separated state in which the sheet to be separated is separated from the sheet supply roller, and
The lift cam and the lift member are configured such that when the lift cam rotates at a constant angular speed, the lift member rotates at a substantially constant angular speed ,
The lift member has a sheet placement surface on which a sheet is placed;
The pressed surface, when viewed in the direction of the rotation axis of the lift member, is a first pressed surface that extends substantially parallel to the sheet placement surface, and the supply of sheets on the first pressed surface. A second pressed surface that is located on the downstream side of the direction and that inclines so as to approach the sheet placement surface,
The lift member rotates so as to approach or separate from the sheet supply roller when the first pressed surface and the second pressed surface are pressed by the cam surface of the lift cam. ,
The cam surface, when viewed in the direction of the axis of rotation of the lift cam, the sheet feeding apparatus that have a shape of substantially involute curve. In the process in which the lift cam rotates from the position where the lift member is farthest from the peripheral surface of the sheet supply roller until the lift member contacts the peripheral surface of the sheet supply roller via the sheet, the cam surface The sheet feeding apparatus according to claim 1, wherein the sheet pressing surface is pressed. 3. The sheet feeding device according to claim 1, wherein the lift cam is configured to be separable from the pressed surface in a state where the lift member is in contact with the peripheral surface of the sheet feeding roller via the sheet. . The lift member, the sheet on the peripheral surface opposite to the position of the supply roller, the sheet feeding apparatus according to any one of claims 1 to 3 having a high friction portion coefficient of friction is greater than the peripheral surface. Said sheet feeding roller, a sheet feeding apparatus according to any one of claims 1 to 4 substantially provided so immovably in the direction direction and spaced closer to the lift member. An apparatus main body having an image forming unit therein;
Image forming apparatus and a sheet feeding apparatus according to claim 1 which is disposed outside the apparatus main body 5.

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