JP5460636B2 - Sheet material feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet material feeding apparatus that feeds a sheet material to an image forming unit or the like in the image forming apparatus, and an image forming apparatus including the sheet material feeding apparatus.

The sheet material feeding device is a device that constitutes a part of an image forming apparatus such as a copier or a printer, and peripheral devices thereof, and for example, feeds the sheet material to an image forming unit of the image forming apparatus. The sheet material feeding device is, for example, arranged on the lower surface side on the downstream side of the sheet material placed on the sheet material placing portion on which the sheet material is placed, and on the downstream side of the sheet material Operates to raise or lower the sheet material lift member, the sheet material lift member capable of changing the posture to a feeding posture that is raised so as to lift the end portion and a retracted posture that maintains the state where the sheet material is placed. A lift actuating member; and a feeding roller that feeds the sheet material by rotating while abutting against the upper surface of the sheet material lifted by the sheet material lift member.
In such a sheet material feeding apparatus, the sheet material lift member is lifted by the lift operation member so that the downstream end of the sheet material is lifted, and the feeding roller is brought into contact with the upper surface of the sheet material in this lifted state. By rotating the sheet material, the sheet material can be sent out (feeded).

  In the above-described sheet material feeding apparatus, the rising limit position (upper limit position) of the sheet material to be fed is an important element for smooth sheet material feeding. For example, if the upper limit position of the sheet material is too high, the contact pressure of the sheet material to the feeding roller becomes excessive, and multi-feed that is fed while the sheet material overlaps easily occurs. On the other hand, if the upper limit position of the sheet material is too low, the contact pressure of the sheet material to the sheet feeding roller is insufficient and air feeding is likely to occur.

  By the way, there are a plurality of types of sheet materials to be fed having different thicknesses. In a device that has not been specially devised for the upper limit position of the sheet material, when feeding multiple types of sheet materials with different thicknesses, the contact pressure between the sheet material and the sheet feeding roller becomes excessive, and the sheet This may cause a feeding failure such as clogging without feeding the material, or excessive force acting on the sheet material to cause wrinkles on the sheet material.

  Conventionally, regardless of the thickness of the sheet material, the upper limit position of the sheet material is regulated by detecting the lift of the lift member in order to prevent paper feeding problems such as double feeding, idle feeding, and wrinkles. As for the upper limit sensor, a sheet material feeding device has been proposed in which the detection height position is configured to be variable up and down (see, for example, Patent Document 1).

JP 2000-344359 A

  However, in the sheet material feeding device described in Patent Document 1, a configuration for making the detection height position of the upper limit sensor variable is necessary, and the sheet material has a thickness during the feeding operation. A configuration for changing the height position of the upper limit sensor in accordance with the change to a different one is also required. This complicates the structure of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet material feeding apparatus that has a simple structure and is less likely to cause feeding problems such as double feeding and idle feeding even when sheet materials having different thicknesses are used.
Another object of the present invention is to provide an image forming apparatus including the sheet material feeding device.

  The present invention is a sheet material feeding device that feeds a sheet material, and is placed on the sheet material placing unit on which the sheet material before being fed is placed, and on the sheet material placing unit A sheet material lifting member that is disposed on the lower surface side of the downstream side of the sheet material and is given an upward urging force in the upward direction, and is lifted to lift the downstream end of the sheet material to supply the sheet material. A sheet material lift member capable of changing the attitude to a feeding posture for feeding, a retracted posture for maintaining the state where the sheet material is placed and not feeding the sheet material, and raising or lowering the sheet material lift member A lift actuating member that operates so as to cause the sheet material lift member to face the upper surface of the sheet material lift member, and is provided with a downward biasing force in a descending direction, and the sheet material lift member in the feeding posture The upper surface of the sheet material lifted by By rotating the feed roller while abutting it, a feed roller that feeds out the sheet material, a roller position sensor that detects a height direction position of the feed roller, and directly or indirectly to the lift operation member In particular, a downward pressing member that applies a pressing force in a downward direction against the upward biasing force to switch the posture of the sheet material lift member to the feeding posture or the retracting posture, and the downward pressing member Of the feeding posture, the height direction position of the feeding roller is controlled to be held within a predetermined range by the roller position sensor, depending on the posture of the descending pressing member driving unit to be driven and the sheet material lift member. The first feeding posture and the height direction position of the feeding roller are controlled without being controlled by the roller position sensor within a predetermined range. A lowering pressing member control unit that controls the lowering pressing member drive unit so as to switch between the second feeding posture in which the height direction position of the roller is determined by the rising biasing force and the lowering biasing force and the retracting posture; The present invention relates to a sheet material feeding device including

  The lift actuating member switches the lifting member abutting on the lower surface of the sheet material lifting member, and switches the posture of the sheet material lifting member to the first feeding posture, the second feeding posture, and the retracting posture. As described above, it is preferable to include a shaft member that rotates the lifting member, and a lever member that rotates integrally with the shaft member and is applied with the pressing force from the descending pressing member.

  Moreover, it is preferable that the said downward pressing member drive part consists of a motor and a gear train group which rotate the said downward pressing member.

  In addition, when the posture of the sheet material lift member is the second feeding posture, it is detected that the leading end portion of the sheet material is sandwiched between rollers on the downstream side in the feeding direction from the sheet material placement portion. When this is done, the lowering pressing member control unit drives the lowering pressing member driving unit to change the posture of the sheet material lift member from the second feeding posture to the first feeding posture. Is preferred.

  The present invention also relates to an image forming apparatus including the sheet material feeding device and an image forming unit that forms an image on the sheet material fed by the sheet material feeding device.

According to the present invention, it is possible to provide a sheet material feeding device that has a simple structure and is less likely to cause feeding problems such as double feeding and idle feeding even when different thickness sheet materials are used.
In addition, according to the present invention, an image forming apparatus including the sheet material feeding device can be provided.

FIG. 2 is a side view for explaining the arrangement of each component of the copier 1 as an embodiment of the image forming apparatus of the present invention. 3 is a perspective view showing an overall configuration of a manual paper feed unit 64. FIG. FIG. 4 is a perspective view illustrating a manual sheet feeding unit 64 in a state where an upper cover unit 401 and a front cover unit 402 illustrated in FIG. 2 are removed. It is a perspective view showing a manual feed tray 65 in a state where the sheet material lift member 62 is lowered. FIG. 6 is a perspective view showing a manual feed tray 65 in a state where a sheet material lift member 62 is raised. FIG. 6 is a perspective view showing a state in which a lift operation member 500 is incorporated in a manual feed tray 65. It is sectional drawing along the AA cutting line shown in FIG. It is a perspective view which shows the principal part of the feeding roller holder 411 in the state of the 1st feeding attitude | position. It is a perspective view which shows the principal part of the feeding roller holder 411 in the state of the 2nd feeding attitude | position. FIG. 9 is an enlarged perspective view showing the vicinity of a feeding roller 66 in the state shown in FIG. 8. FIG. 10 is an enlarged perspective view showing the vicinity of a feeding roller 66 in the state shown in FIG. 9. FIG. 10 is a side view showing an operating state of the lowering mechanism when the sheet material lift member is switched to a retracted posture. FIG. 10 is a side view showing an operating state of the lowering mechanism when the sheet material lift member is switched to the first feeding posture. FIG. 10 is a side view showing an operation state of the lowering mechanism when the sheet material lift member is switched to the second feeding posture. 4 is a side view showing a state where a manual feed tray 65 of the manual paper feed unit 64 is closed so as to constitute a part of the right side surface of the apparatus main body M. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, with reference to FIG. 1, the overall structure of a copier 1 as an image forming apparatus according to the present embodiment will be described. FIG. 1 is a side view for explaining the arrangement of components of a copier 1 as an embodiment of the image forming apparatus of the present invention.
As shown in FIG. 1, a copier 1 as an image forming apparatus includes an image reading device 200 and an apparatus main body M.

The image reading apparatus 200 includes an image reading unit 201 incorporated in the upper part of the apparatus main body M, and a reading unit cover 210 that covers the upper surface of the image reading unit 201 so as to be opened and closed. The upper surface of the image reading unit 201 is a document placement surface 202 on which the document G is placed. The document G is placed on the document placement surface 202 with the reading unit cover 210 opened.
The image reading apparatus 200 reads an image of the document G placed on the document placement surface 202 by the image reading unit 201 and sends information of the read image to the image forming unit GK incorporated in the apparatus main body M. .

  The apparatus main body M includes an image forming unit GK that forms a predetermined toner image on a sheet T as a sheet material based on image information sent from the image reading apparatus 200, and feeds the sheet T to the image forming unit GK and a toner. A paper supply / discharge section KH that discharges the paper T on which an 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, 11 b, 11 c, 11 d, static eliminators 12 a, 12 b, 12 c, 12 d, a transfer roller 8, and a fixing unit 9.

  As shown in FIG. 1, the paper supply / discharge unit KH includes a paper feed cassette 52, a manual paper feed unit 64, a transport path L of the paper T, a registration roller pair 80, and a paper discharge unit 50.

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, the charging by the charging units 10a, 10b, 10c, and 10d, the laser scanner unit 4a, the charging unit 10a, 10b, 10c, and 10d in order from the upstream side to the downstream side along the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Exposure by 4b, 4c, 4d, development by developing devices 16a, 16b, 16c, 16d, primary transfer by intermediate transfer belt 7 and primary transfer rollers 37a, 37b, 37c, 37d, static eliminators 12a, 12b, 12c, 12d Is eliminated, and cleaning is performed by the drum cleaning units 11a, 11b, 11c, and 11d.
In the image forming unit GK, the secondary transfer by the intermediate transfer belt 7, the secondary transfer roller 8 and the opposing roller 18 and the 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 read by the image reading unit 201. 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. Each of the toner supply units 6a, 6b, 6c, and 6d supplies the respective color toners stored in the toner cartridges 5a, 5b, 5c, and 5d 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 over 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.

  The 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 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 a 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 separation position where the secondary transfer roller 8 is separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is disposed at the 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. Are arranged at spaced positions.

  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 counter 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. The full-color toner image primarily transferred to the intermediate transfer belt 7 at the secondary transfer nip N2 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 to fix it 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 heating rotator 9a and the pressure rotator 9b sandwich and pressurize the paper T on which the toner image has been secondarily transferred, and convey the paper T. When the paper T is conveyed in a state of being sandwiched between the heating rotator 9a and the pressure rotator 9b, the toner transferred to the paper T is melted and pressurized and fixed to the paper T. The

Next, the paper supply / discharge unit KH will be described.
As shown in FIG. 1, in the lower part of the apparatus main body M, a single paper feed cassette 52 that stores paper T is disposed. The paper feed cassette 52 is configured to be drawable from 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 paper feed side end of the paper feed cassette 52 (the right end in FIG. 1). . The cassette paper feed unit 51 includes a forward feed roller 84 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.

On the right side surface (right side in FIG. 1) of the apparatus main body M, a manual sheet feeding unit 64 is provided as a sheet material feeding device that feeds the paper T as a sheet material. The manual paper feed unit 64 is provided mainly for feeding paper T of a size and type different from the paper T set in the paper feed cassette 52 to the first transport path L1 via the manual transport path La. It is done. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the right side surface of the apparatus main body M in the closed state, and a feed roller 66. The lower end of the manual feed tray 65 is attached to the vicinity of the feeding roller 66 so as to be rotatable (openable and closable). The open manual feed tray 65 functions as a sheet material placement unit on which the paper T before being fed is placed. The 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 that reverses the sheet conveyed to the side and returns it to the first conveyance path L1.

  The first transport path L1 transports the paper T stored in the paper feed cassette 52 toward the image forming unit GK. The manual feed path La transports the paper T accommodated in the manual paper feed unit 64 toward a registration roller pair 80 described later.

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 paper detection sensor (not shown) for detecting the paper 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 correction and timing adjustment based on the detection signal information from the paper detection sensor.

  Between the 1st junction part P1 and the 2nd junction part P2 in the 1st conveyance path L1, the 1st conveyance roller pair 82 is arrange | positioned. The first transport roller pair 82 is disposed on the downstream side of the paper feed roller pair 81, sandwiches the paper T transported by the paper feed roller pair 81, and transports the paper T 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. In the return conveyance path Lb, a plurality of second conveyance roller pairs 83 that convey the paper T toward the second joining portion P2 are arranged at predetermined intervals. 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 is disposed upstream of the secondary transfer roller 8. It can be conveyed upstream of the registration roller pair 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 branch member 58 is provided in the first branch portion Q1. The branching member 58 branches the transport direction of the paper T that is transported from 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 conveys the third conveyance path L3 from the downstream side toward the upstream side is branched 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 left side of the apparatus body M (left 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 transported from the upstream side to the downstream side in the third transport path L3 is discharged to the outside of the apparatus main body M, and the transport 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 main 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 is formed by a top cover member M2 as an opening / closing member that constitutes a part of the top surface of the apparatus main body M. On the upper surface of the top cover member M2 forming the paper discharge stacking unit M1, the paper T discharged from the paper discharge unit 50 in a state where a predetermined toner image is formed is stacked and stacked.
A sheet detection sensor is disposed at a predetermined position in each conveyance path.

Next, with reference to FIG. 1, the operation of the copier 1 of the present embodiment will be briefly described.
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 stored in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 84 and the paper feed roller pair 81, and then the first transport path L1 and the first transport path L1 through the first transport path L1. The sheet is conveyed to the registration roller pair 80 by the one conveyance roller pair 82.
In the registration roller pair 80, skew correction of the paper T and timing adjustment with toner image formation in the image forming unit GK 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. Then, 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. Introduced into the fixing nip. Then, the toner melts in the fixing nip, 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 feed roller 66 and is fed by the manual feed roller pair 421. Further, after being sent out, it is conveyed to the registration roller pair 80 via the first junction 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 copier 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 along the third transport path L3, the paper T is branched to the return transport path Lb by the branching member 58, and thereafter, 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 paper T is corrected or adjusted by the registration roller pair 80, and is introduced into the secondary transfer nip N2 through the first conveyance path L1. As the sheet T passes through the return conveyance path Lb, the non-printed surface faces the intermediate transfer belt 7. A toner image is transferred onto the unprinted surface, and as a result, duplex printing is performed.

  Next, with reference to FIGS. 2 to 7, details of the manual sheet feeder 64 as the sheet material feeding device will be described. FIG. 2 is a perspective view showing the overall configuration of the manual sheet feeder 64. FIG. 3 is a perspective view showing the manual sheet feeder 64 with the upper cover 401 and the front cover 402 shown in FIG. 2 removed. FIG. 4 is a perspective view showing the manual feed tray 65 in a state where the sheet material lift member 62 is lowered. FIG. 5 is a perspective view showing the manual feed tray 65 in a state where the sheet material lift member 62 is raised. FIG. 6 is a perspective view showing a state in which the lift operation member 500 is incorporated in the manual feed tray 65. 7 is a cross-sectional view taken along the line AA shown in FIG.

  As shown in FIGS. 2 to 7, the manual sheet feeder 64 in the present embodiment includes a manual tray 65 having a sheet material placement unit 61 and a sheet material lift member 62, a feeding roller 66 (see FIG. 1), and The sheet feeding unit 40, the lift operating member 500, and the lowering mechanism 70 are provided.

The sheet material placement unit 61 is a tray body that is a main body of the manual feed tray 65 on which the paper T before being fed is placed. The sheet material placing portion 61 is attached to the housing 63. The sheet material placing portion 61 includes a main tray portion 611 and an extension tray portion 612 that can be pulled out from the main tray portion 611 in the direction opposite to the feeding direction.
The main tray portion 611 is rotatably connected to the right side portion of the apparatus main body M of the copier 1 at the downstream end in the paper feeding direction.
The extension tray section 612 is attached to the main tray section 611 so as to be drawn out or accommodated through an opening formed at the upstream end of the main tray section 611 in the sheet feeding direction.

When the manual feed tray 65 is not used, the extension tray portion 612 is accommodated in the main tray portion 611, and the main tray portion 611 is rotated so as to be closed with respect to the apparatus main body M. A part of the right side surface of M is formed.
Further, when the manual feed tray 65 is used, the main tray portion 611 is rotated so that the right side surface of the apparatus main body M is opened, and the paper T can be placed on the sheet material placement portion 61. Further, by pulling out the extension tray portion 612 as necessary, a large size paper T can be placed on the sheet material placement portion 61.

  As shown in FIGS. 2 to 7, the sheet material lift member 62 is arranged on the lower surface side on the downstream side of the paper T placed on the sheet material placement portion 61. It is assembled on the upper surface on the downstream side in the paper feeding direction. The upper surface 62 </ b> A of the sheet material lift member 62 serves as a placement surface on which the downstream side of the paper T placed on the sheet material placement portion 61 is placed.

The sheet material lift member 62 has a pair of movable side walls that regulate the positions of the lift member main body 621 and both sides of the paper T placed on the sheet material placement portion 61 (both sides in the Y direction orthogonal to the paper feed direction). 622 and an introduction plate portion 623. The pair of movable side walls 622 are provided so as to be movable in the width direction (Y direction) of the paper T, as indicated by an arrow Y1 in FIGS.
The pair of movable side walls 622 can move in a direction away from or close to each other, and can position both sides of the paper T of various sizes.
The introduction plate portion 623 is connected to the end portion of the lift member main body 621 on the downstream side in the sheet feeding direction, and is disposed to face the feeding roller 66.

  As shown in FIGS. 5 to 7, the sheet material lift member 62 is rotated so as to raise the downstream end 62 </ b> B by an upward rotation operation of a lift operation member 500 described later. As a result, the downstream end of the paper T is lifted, and the feeding posture for feeding the paper T is changed. Further, the sheet material lift member 62 is rotated so as to lower the downstream end 62B as shown in FIGS. 2 to 4 by the downward rotation of a lift operation member 500 described later. As a result, the downstream end of the paper T is lowered, and the sheet material lift member 62 is changed to a retracted posture in which the paper T is not fed while maintaining the state where the paper T is placed.

  Although not shown, the sheet material lift member 62 is rotatably engaged with the sheet material placement portion 61 at the upstream end portion 62C. As shown by an arrow R1 in FIG. 7, the sheet material is moved so that the downstream end 62B moves upward with the upstream end 62C as a rotation fulcrum, as shown by an arrow R1 in FIG. The lift member 62 rotates. This rotation is called rotation in the positive direction. That is, the sheet material lift member 62 rises by rotating in the forward direction and descends by rotating in the reverse direction.

  The feeding roller 66 is disposed to face the upper surface 62 </ b> A of the sheet material lift member 62. The feeding roller 66 feeds the paper T by rotating the feeding roller 66 while abutting the upper surface of the paper T lifted by the sheet material lift member 62 in the feeding posture. Specifically, in the feeding posture in which the downstream end 62B of the sheet material lift member 62 is lifted by the lift operation member 500, when the sheet T is lifted by the lift of the sheet material lift member 62, the feed roller 66 It contacts the upper surface of the paper T placed on the material lift member 62. As the feeding roller 66 in contact with the paper T rotates, the paper T is sent out from the sheet material lift member 62 to the manual feed path La in the apparatus main body M. In the present embodiment, the feeding roller 66 is made of hollow rubber.

  As shown in FIGS. 2 and 3, the paper feed unit 40 is configured in a housing structure having an upper cover part 401, a front cover part 402, a right wall part 403, and a left wall part 404. . A plurality of ribs 401 </ b> L are formed on the surface of the upper cover portion 401. The plurality of ribs 401L function as guide surfaces that guide the conveyance of the paper T that is conveyed along the return conveyance path Lb (see FIG. 1).

  Next, a specific configuration of the paper feeding unit 40 will be described with reference to FIGS. FIG. 8 is a perspective view showing a main part of the feeding roller holder 411 in the state of the first feeding posture. FIG. 9 is a perspective view illustrating a main part of the sheet feeding unit 40 feeding roller holder 411 in the second feeding posture state. FIG. 10 is an enlarged perspective view showing the vicinity of the feeding roller 66 in the state shown in FIG. FIG. 11 is an enlarged perspective view showing the vicinity of the feeding roller 66 in the state shown in FIG.

  As shown in FIGS. 3, 8, and 9, the paper feeding unit 40 has the paper T placed on the feeding roller holder 411 that holds the feeding roller 66, the feeding roller 66, and the sheet material placement unit 61. And a roller position sensor 413 that detects the height direction position of the feeding roller 66, and a roller unit 42 that conveys the paper T.

  The feed roller holder 411 is supported by the housing of the paper feed unit 40 so as to be swingable up and down around a shaft 41 (see FIGS. 8 and 9). The feed roller holder 411 is urged to swing downward around the shaft 41 by a coil spring 417 (see FIG. 10) interposed between the feed roller holder 411 and the feed roller holder 411. The feeding roller 66 is rotatably held on the side opposite to the shaft 41 in the feeding roller holder 411. That is, the feeding roller holder 411 and the feeding roller 66 are provided with a downward biasing force in the downward direction. In a state where the paper T is placed on the sheet material placement portion 61, the upper surface of the paper T comes into contact with the peripheral surface of the feeding roller 66 by raising the sheet material lift member 62. Further, the feeding roller 66 and the feeding roller holder 411 are lifted upward against the downward biasing force of the coil spring 417.

  The feeding roller holder 411 has a guide stopper 418 that protrudes upward. A guide hole 419 is provided in the housing of the paper feed unit 40 located above the guide stopper 418. The guide stopper 418 is disposed in the guide hole 419. In this state, the guide stopper 418 and the guide hole 419 guide the vertical swing of the feeding roller holder 411 around the shaft 41 and restrict the lower limit positions of the feeding roller holder 411 and the feeding roller 66.

  The swing piece 412 is swingably supported by the housing of the paper feed unit 40. On the swing locus of the swing piece 412, a light sensor that emits light and a light sensor (not shown) that receive light are arranged. In a state where the paper T is placed on the sheet material placement portion 61, the light emitted from the optical sensor is blocked as the swinging piece 412 is swung upwardly by the paper T. The Accordingly, the swing piece 412 detects that the paper T is placed on the sheet material placement portion 61.

  The roller position sensor 413 has a photo interrupter (PI) and detects the height direction position of the feeding roller 66. Thereby, for example, the roller position sensor 413 ensures that a predetermined contact pressure (sheet feeding pressure) is secured between the feeding roller 66 and the paper T (sheet material) when the sheet material lifting member 62 is lifted to a predetermined position. It is detected whether it was done. As shown in FIGS. 8 to 11, the roller position sensor (PI) 413 can be disposed in the gap between the light emitting element 414, the light receiving element 415 arranged to face the light emitting element 414 with a predetermined gap therebetween. A light shielding plate 416. The light shielding plate 416 of the roller position sensor 413 is attached to the upper surface of the feeding roller holder 411 and swings up and down together with the feeding roller holder 411.

  As illustrated in FIG. 3, the roller unit 42 includes a manual conveyance roller pair 421 and a roller holder 422 that rotatably supports the manual conveyance roller pair 421. A plurality of roller units 42 are arranged in a row at appropriate intervals in a direction orthogonal to the transport direction (feed direction) of the paper T. Although four roller units 42 are provided in FIG. 3, it may be two or more. The coil spring 423 biases a part of the manual feed roller pair 421 of each roller unit 42 so as to protrude from the left wall portion 404 in the transport direction of the paper T.

Next, the lift operation member 500 will be described.
The lift operation member 500 operates to raise or lower the sheet material lift member 62. As shown in FIGS. 6 and 7, the lift operating member 500 includes a lifting member 511 that contacts the lower surface of the sheet material lifting member 62, a shaft member 512 that rotates the lifting member 511, and a lever member that is attached to the shaft member 512. 530 and a coil spring 513 that urges the lifting member 511.

The lifting member 511 includes a free end 511 </ b> A that contacts the rib portion 62 </ b> L on the lower surface of the sheet material lifting member 62, and a base end portion 511 </ b> B that is inserted through the shaft member 512 and fixed.
The shaft member 512 is rotatably supported by the housing 63. The shaft member 512 rotates the lifting member 511 so that the posture of the sheet material lift member 62 can be switched between a first feeding posture (described later), a second feeding posture (described later), and a retracted posture.

  The lever member 530 rotates integrally with the shaft member 512. A pressing force is applied to the lever member 530 from the descending pressing member 71. The lever member 530 includes a cylindrical body part 531, a lever main body part 532 integrated with the cylindrical body part 531, and a distal end part 533 integrated with the lever main body part 532. The lever member 530 is rotatably supported around the axis of the shaft member 512 by fitting the cylindrical portion 531 to the shaft member 512. The leading end portion 533 is disposed on the downstream side of the cylindrical body portion 531 in the paper T feeding direction. When the lever member 530 rotates around the axis of the shaft member 512, the lifting member 511 rotates integrally with the lever member 530 in the same direction. The lever member 530 is given an upward biasing force that rotates in the direction of rising around the axis of the shaft member 512 (the direction in which the posture of the sheet material lift member 62 is the feeding posture) by the coil spring 513.

  The coil spring 513 gives the lifting member 511 an upward biasing force that lifts the lifting member 511 upward. In response to the upward biasing force of the coil spring 513, the lifting member 511 is lifted upward. As a result, the sheet material lift member 62 is lifted so as to lift the downstream end of the paper T, and the posture of the sheet material lift member 62 is changed to a feeding posture for feeding the paper T.

  Next, the lowering mechanism 70 which is a characteristic configuration of the manual sheet feeder 64 will be described with reference to FIGS. FIG. 12 is a side view showing an operating state of the lowering mechanism 70 when the sheet material lifting member 62 is switched to the retracted posture. FIG. 13 is a side view showing an operating state of the lowering mechanism 70 when the sheet material lift member 62 is switched to the first feeding posture. FIG. 14 is a side view showing an operating state of the lowering mechanism 70 when the sheet material lift member 62 is switched to the second feeding posture. FIG. 15 is a side view showing a state in which the manual tray 65 of the manual sheet feeder 64 is closed so as to constitute a part of the right side surface of the apparatus main body M.

As shown in FIGS. 12 to 15, the lowering mechanism 70 includes a lowering pressing member 71, a lowering pressing member driving unit 72, and a lowering pressing member control unit 73.
The descending pressing member 71 includes a pressing member main body 711, a cylindrical body portion 712 on one end side of the pressing member main body 711, and a curved tip end portion 713 on the other end side of the pressing member main body 711. The curved leading end portion 713 is disposed on the upstream side of the cylindrical body portion 712 in the paper T feeding direction. The descending pressing member 71 is configured to swing up and down around the axis of the rotating shaft 74 by fitting the cylindrical portion 712 on one end side thereof to the rotating shaft 74.

  A lower surface 715 of the pressing member body 711 on the curved distal end 713 side is formed in a flat shape. A front end 533 of the lever member 530 is in contact with the lower surface 715. The descending pressing member 71 applies a pressing force in a direction to descend against the lever member 530 of the lift operating member 500 against the rotational biasing force of the coil spring 513 in the upward direction of the lever member 530. Thereby, the downward pressing member 71 switches the posture of the sheet material lift member 62 to the feeding posture or the retracting posture.

The descending pressing member driving unit 72 drives the descending pressing member 71. The descending pressing member driving unit 72 includes a motor 720, a gear train group 721, and an eccentric cam 726 for posture change. The gear train group 721 includes a worm 722, a worm wheel 723, a first reduction gear pair 724, and a second reduction gear pair 725.
The motor 720 is a DC motor that can be switched between forward and reverse, and rotationally drives the eccentric cam 726 via a gear train group 721. The worm 722 of the gear train group 721 is fixed to the output shaft of the motor 720. The worm wheel 723, the first reduction gear pair 724, and the second reduction gear pair 725 are respectively connected to the first shaft 733, the second shaft 734, and the third shaft 735 fixed to the front cover portion 402 of the paper feed unit 40, respectively. It is supported so that it can rotate freely.

  The eccentric cam 726 rotates around the axis of the rotation shaft 736. On the circumferential surface of the eccentric cam 726, there are a large-diameter portion 726A having a large eccentric amount, a small-diameter portion 726C having a small eccentric amount, and an intermediate-diameter portion 726B positioned between the large-diameter portion 726A and the small-diameter portion 726C. 12 is formed continuously in the rotation direction indicated by the arrow R2. The circumferential surface of the eccentric cam 726 is in contact with (pressed against) the upper surface 714 of the pressing member main body 711 in the descending pressing member 71.

  The descending pressing member control unit 73 controls the operation of the descending pressing member driving unit 72 based on the output signal from the roller position sensor 413. Specifically, the descending pressing member control unit 73 is configured so that the sheet material lift member 62 has a posture in which the sheet T having a normal thickness can be fed in the feeding posture and the thickness in the feeding posture. The rotation of the motor 720 in the lowering pressing member driving unit 72 is controlled so as to switch between a second feeding posture capable of feeding a large paper T and a retracting posture where the paper T is not fed.

  The first feeding posture is a posture controlled to hold the height direction position of the feeding roller 66 within a predetermined range by the roller position sensor 413 among the feeding postures. In the first feeding posture, the position of the sheet material lift member 62 is regulated by the lowering pressing member 71 at the position where the feeding roller 66 is detected. Therefore, the upward biasing force does not appear 100% in the sheet material lift member 62.

  The second feeding posture is a posture capable of feeding a sheet T having a thickness larger than that of the sheet T having a normal thickness. The second feeding posture is the height of the feeding roller 66 without controlling the height direction position of the feeding roller 66 within the predetermined range by the roller position sensor 413 in the feeding posture. The orientation is determined by the upward biasing force of the sheet material lift member 62 and the downward biasing force of the feeding roller 66. In the second feeding posture, the position of the sheet material lifting member 62 is not restricted by the descending pressing member 71. Therefore, the upward biasing force can be exerted on the sheet material lift member 62 100%.

The thick paper T is generally called a thick paper.
Switching between the first feeding posture, the second feeding posture, and the retracting posture is selected by the user using an operation button (not shown).

Next, the operation of the lowering mechanism 70 configured as described above will be described.
The main tray portion 611 of the sheet material placing portion 61 in the manual feed tray 65 is rotated so as to open the right side surface of the apparatus main body M, and the sheet material lift member 62 is switched to the retracted posture as shown in FIGS. 12, the large-diameter portion 726A of the eccentric cam 726 in the descending pressing member driving unit 72 is in contact with the upper surface 714 of the pressing member main body 711 in the descending pressing member 71 and the lever member as shown in FIG. The front end portion 533 of the 530 comes into contact with the lower surface 715 of the pressing member main body 711.
Accordingly, the lever member 530 and the lift operation member 500 are pressed in a direction in which the lever member 530 and the lift operation member 500 are lowered against the upward biasing force of the coil spring 513. Further, the sheet material lift member 62 is held in a retracted posture as shown in FIGS.

  Next, in the above-described retracted posture, when the user operates the operation button to select the first feeding posture, the motor 720 rotates. The rotational force is transmitted to an eccentric cam 726 for posture change through a gear train group 721 including a worm 722, a worm wheel 723, a first reduction gear pair 724, and a second reduction gear pair 725. As a result, the eccentric cam 726 is rotated around the axis of the rotation shaft 736. Due to the rotation of the eccentric cam 726, the lowering pressing member 71 swings upward around the axis of the rotation shaft 74. Along with this swinging, the lever member 530 and the lift operation member 500 are raised by the upward biasing force of the coil spring 513.

  Then, as shown in FIG. 12, when the large diameter portion 726 </ b> A of the eccentric cam 726 is in contact with the upper surface 714 of the pressing member main body 711 in the descending pressing member 71, the light shielding plate 416 of the feeding roller holder 411 is detected by the roller position sensor 413. Is not detected. From this state, the motor 720 is rotated so that the eccentric cam 726 rotates until the light shielding plate 416 of the feeding roller holder 411 is detected by the roller position sensor 413. In this process, when the light shielding plate 416 of the feeding roller holder 411 is detected by the roller position sensor 413, based on the output signal from the roller position sensor 413, the control signal output from the descending pressing member control unit 73 The rotation of the motor 720 is stopped.

  When the rotation of the motor 720 stops, the sheet material lift member 62 rises via the lever member 530 and the lift operation member 500 and switches to the first feeding posture as shown in FIGS. It is done. Since the position of the sheet material lift member 62 is regulated by the lowering pressing member 71 at the position where the feeding roller 66 is detected, the upward biasing force is never expressed in the sheet material lift member 62.

  In the first feeding posture, when the sheet T is lifted by the lift of the sheet material lift member 62, the feeding roller 66 rotates in contact with the upper surface of the sheet T placed on the sheet material lift member 62. . As a result, the sheet T having the normal thickness is sent from the sheet material lift member 62 to the manual feed path La in the apparatus main body M.

  When the paper T placed on the sheet material lift member 62 is fed and decreased, the height direction position of the paper T placed on the sheet material lift member 62 is lowered accordingly. Become. Since the sheet material lift member 62 does not rise, the feeding roller 66 and the light shielding plate 416 of the feeding roller holder 411 are lowered. When the light shielding plate 416 deviates from the detection position of the roller position sensor 413, the motor 720 is rotated so that the eccentric cam 726 is rotated until the light shielding plate 416 is detected by the roller position sensor 413. Thereafter, when the light shielding plate 416 is detected by the roller position sensor 413, the rotation of the motor 720 is stopped so that the rotation of the eccentric cam 726 is stopped. In other words, the roller position sensor 413 performs control to make the position in the height direction (vertical direction) of the topmost paper T constant.

  In summary, when the paper T placed on the sheet material placement unit 61 and the sheet material lift member 62 is fed and decreased, the height position of the feed roller 66 is adjusted by the roller position sensor 413. When it is detected that the predetermined range defined as one feeding posture is deviated, the downward pressing member control unit 73 performs downward pressing so as to hold the height direction position of the feeding roller 66 within the predetermined range. The member driving unit 72 is controlled.

  Further, in the above-described retracted posture or the first feeding posture, when the user operates the operation button to select the second feeding posture, the motor 720 rotates. The rotational force is transmitted to an eccentric cam 726 for posture change through a gear train group 721 including a worm 722, a worm wheel 723, a first reduction gear pair 724, and a second reduction gear pair 725. As a result, the eccentric cam 726 is rotated around the axis of the rotation shaft 736. Due to the rotation of the eccentric cam 726, the lowering pressing member 71 swings upward around the axis of the rotating shaft 74. With this swinging, the lever member 530 and the lift operating member 500 are lifted by the coil spring 513. It rises by.

  Then, as shown in FIG. 12, from the state where the large diameter portion 726A of the eccentric cam 726 contacts the upper surface 714 of the pressing member main body 711 in the descending pressing member 71, as shown in FIG. 14, the small diameter portion 726C of the eccentric cam 726. The motor 720 is rotated so that the eccentric cam 726 is rotated until it comes into contact with the upper surface 714 of the pressing member main body 711 in the lowering pressing member 71. When the eccentric cam 726 rotates to this position, the rotation of the motor 720 is stopped. Further, since the position of the sheet material lift member 62 is not regulated by the descending pressing member 71, the upward biasing force can be exerted on the sheet material lift member 62 100%. As a result, the height direction position of the sheet material lift member 62 can be moved to a position higher than the position in the first feeding posture. Accordingly, when comparing one or more sheets T (sheet material) having the same thickness, the contact pressure (sheet feeding pressure) between the feeding roller 66 and the sheet T (sheet material) is the first. It becomes higher than the contact pressure (feed pressure) in the feeding posture.

  When the sheet T is lifted by the rising of the sheet material lifting member 62 in the second feeding posture, the feeding roller 66 rotates in contact with the upper surface of the sheet T placed on the sheet material lifting member 62. . As a result, the sheet T having a thickness larger than the normal thickness is sent out from the sheet material lift member 62 to the manual feed path La in the apparatus main body M.

  Further, when the posture of the sheet material lift member 62 is the second feeding posture, the manual feed roller pair 421 (see FIG. 3) where the leading end portion of the paper T is downstream of the sheet material placement portion 61 in the feeding direction. ), The downward pressing member control unit 73 drives the downward pressing member to change the posture of the sheet material lift member 62 from the second feeding posture to the first feeding posture. The unit 72 is driven.

  Note that a curved surface 716 curved at approximately 90 degrees extending from one end of the flat lower surface 715 to the curved distal end 713 is formed at the distal end of the pressing member main body 711. The distal end portion 533 of the lever member 530 is formed in an arc shape. Accordingly, as shown in FIG. 15, when the main tray portion 611 of the sheet material placing portion 61 in the manual feed tray 65 is rotated so as to close the right side surface of the apparatus main body M, the arcuate tip of the lever member 530 The part 533 moves while sliding on the curved surface 716 at the tip of the pressing member main body 711. Thereby, the lever member 530 is accommodated in the inside of the apparatus main body M in the state changed to the attitude | position in which the front-end | tip part 533 is located lowest.

According to this embodiment, the following effects are produced.
The manual sheet feeding unit 64 (sheet material feeding device) according to the present embodiment is disposed on the lower surface side on the downstream side of the paper T (sheet material) placed on the sheet material placing unit 61 and rises in the ascending direction. The sheet material lifting member 62 to which the urging force is applied, the sheet material lifting member 62 being lifted so as to lift the downstream end of the paper T and feeding the paper T, and the state where the paper T is placed A sheet material lift member 62 that can be changed to a retracted posture in which the paper T is not fed and maintained, a lift operation member 500 that operates to raise or lower the sheet material lift member 62, and a sheet material lift member The feeding roller 66 is opposed to the upper surface of the sheet 62 and is provided with a downward biasing force in the descending direction, and the feeding roller 66 is placed on the upper surface of the sheet T lifted by the sheet material lift member 62 in the feeding posture. Rotate while abutting Thus, the feeding roller 66 that feeds the paper T, the roller position sensor 413 that detects the height direction position of the feeding roller 66, and the lift actuating member 500 are directly or indirectly resistant to the upward biasing force. A downward pressing member 71 that applies a pressing force in the downward direction and switches the posture of the sheet material lift member 62 to the feeding posture or the retracting posture, and a downward pressing member drive unit 72 that drives the downward pressing member 71, The first feeding posture controlled so as to hold the height direction position of the feeding roller 66 within the predetermined range by the roller position sensor 413 among the feeding postures according to the posture of the sheet material lift member 62, and the feeding The height position of the feeding roller 66 is biased upward without controlling the position of the roller 66 in the height direction to be held within a predetermined range by the roller position sensor 413. And a second feeding position determined by the lowering biasing force, to switch to the retracted position, and a lowered pressing member controller 73 which controls the lowering pressing member driving part 72, a.

For this reason, the first feeding posture suitable for feeding a sheet of normal thickness only by drivingly controlling the descending pressing member 71 via the descending pressing member driving unit 72 and the descending pressing member control unit 73 (see FIG. 13). It is possible to switch to the second feeding posture (see FIG. 14) suitable for feeding a sheet having a thickness larger than the normal thickness.
Therefore, the detection height position of the upper limit sensor that regulates the upper limit position of the sheet as the sheet material lift member ascends is configured to be variable up and down so that a feeding posture corresponding to the thickness of the sheet can be obtained. Compared to the sheet material feeding apparatus, the structure can be greatly simplified. In addition, it is no longer necessary to install many components and parts in a narrow space in the device, and it is possible to feed multiple types of paper with different thicknesses while facilitating the production and assembly of the entire device and reducing production costs. Can be made.

Further, in the second feeding posture in which a sheet having a thickness larger than the normal thickness is fed, the sheet material lift member 62 is moved to the feeding roller 66 more than in the first feeding posture in which the sheet having a normal thickness is fed. Move closer. For this reason, when a sheet having a large thickness is fed, a strong contact pressure by the feeding roller 66 can be secured.
Therefore, even paper with a large thickness is less likely to cause feeding problems such as idle feeding and double feeding, and can be fed stably. That is, stable feeding performance can be exhibited with any of a plurality of types of sheets having different thicknesses.

Further, in the present embodiment, the descending pressing member driving unit 72 that drives the descending pressing member 71 includes a motor 720 that rotates the descending pressing member 71 and a gear train group 721.
Therefore, the control structure of the descending pressing member control unit 73 for switching the posture of the sheet material lift member 62 is simple, and the posture switching operation can be performed smoothly and reliably. The second feeding posture and the retracting posture can be maintained in a constant posture. Therefore, even when used for a long time, stable feeding performance can be ensured regardless of the thickness of the paper.

  In the present embodiment, when the posture of the sheet material lift member 62 is the second feeding posture, the leading edge of the paper T is the first transport on the downstream side of the sheet material placement unit 61 in the feeding direction. When it is detected that the sheet is sandwiched between the roller pair 82 (see FIG. 1), the descending pressing member control unit 73 changes the posture of the sheet material lift member 62 from the second feeding posture to the first feeding posture. As described above, the descending pressing member driving unit 72 is driven. Therefore, immediately after switching of the feeding posture, it is possible to suppress the occurrence of conveyance jamming (JAM) due to a sudden increase in the load on the first conveyance roller pair 82 (contact resistance with the paper).

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 present embodiment, the motor 720 and the gear train group 721 are used as the descending pressing member driving unit 72, but the present invention is not limited to this. For example, a motor and a belt-type rotation transmission mechanism may be used as the descending pressing member driving unit. Further, the lowering pressing member 71 may be driven by a motor directly connected to the rotating shaft 74.
The descending pressing member 71 may directly apply a pressing force to the lift operation member 500, or may apply a pressing force via another member or the like.

In the present embodiment, the case where the sheet material feeding device of the present invention is applied to the manual sheet feeding unit 64 has been described, but the present invention is not limited to this. The sheet material feeding device of the present invention can also be applied to a paper feeding cassette 52, a document feeding unit in a document conveying device, and the like.
In this embodiment, a color copier has been described as the image forming apparatus, but the present invention is not limited to this. The image forming apparatus may be, for example, a monochrome copier, a printer, a facsimile, and a complex machine of these.
The sheet material is not limited to paper, and may be, for example, a film-like sheet or a composite sheet of film and paper.

  DESCRIPTION OF SYMBOLS 1 ... Copy machine (image forming apparatus) 61 ... Sheet material mounting part, 62 ... Sheet material lift member, 64 ... Manual paper feeding part (sheet material feeding apparatus), 66 ... Feed roller, 71... Descending pressing member, 72... Descending pressing member drive unit, 73... Descending pressing member control unit, 413. 530 ... Lever member, 720 ... Motor, 721 ... Gear train group, GK ... Image forming part, T ... Paper (sheet material)

Claims (5)

A sheet material feeding device for feeding a sheet material,
A sheet material placement section on which the sheet material before being fed is placed;
A sheet material lift member disposed on the lower surface side on the downstream side of the sheet material placed on the sheet material placement portion and provided with an upward biasing force in the ascending direction, the downstream end portion of the sheet material Sheet material lifting member that can change the posture between a feeding posture for feeding the sheet material by lifting it up and a retracting posture for maintaining the state where the sheet material is placed and not feeding the sheet material When,
A lift actuation member that operates to raise or lower the sheet material lift member;
A feeding roller facing the upper surface of the sheet material lifting member and applied with a downward biasing force in a descending direction, wherein the upper surface of the sheet material lifted by the sheet material lifting member in the feeding posture A feed roller that feeds out the sheet material by rotating the feed roller while abutting it;
A roller position sensor for detecting a height direction position of the feeding roller;
By directly or indirectly applying a pressing force in the direction of descending against the upward biasing force to the lift operating member, the posture of the sheet material lift member is switched to the feeding posture or the retracting posture. A downward pressing member;
A descending pressing member driving section for driving the descending pressing member;
The first feeding posture controlled so as to hold the height direction position of the feeding roller within the predetermined range by the roller position sensor among the feeding postures according to the posture of the sheet material lift member; A second position in which the height direction position of the feeding roller is determined by the upward biasing force and the downward biasing force without controlling the height position of the feeding roller to be held within a predetermined range by the roller position sensor. A lowering pressing member control unit that controls the lowering pressing member drive unit so as to switch between a feeding posture and the retracting posture;
A sheet material feeding device comprising: The lift operating member is:
A lifting member that contacts the lower surface of the sheet material lifting member;
A shaft member that rotates the lifting member so that the posture of the sheet material lifting member can be switched to the first feeding posture, the second feeding posture, and the retracting posture;
The sheet material feeding device according to claim 1, further comprising: a lever member that rotates integrally with the shaft member and is provided with the pressing force from the descending pressing member. The sheet material feeding device according to claim 1, wherein the descending pressing member driving unit includes a motor and a gear train group that rotate the descending pressing member. When the posture of the sheet material lift member is the second feeding posture, it is detected that the leading end portion of the sheet material is sandwiched between rollers on the downstream side in the feeding direction with respect to the sheet material placement portion. In some cases, the lowering pressing member control unit drives the lowering pressing member driving unit to change the posture of the sheet material lift member from the second feeding posture to the first feeding posture. 4. The sheet material feeding device according to any one of items 1 to 3. The sheet material feeding device according to any one of claims 1 to 4,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet material fed by the sheet material feeding device.

Images