JP2024008463A - Image formation device - Google Patents

Abstract

To provide an image formation device that can increase pressing force between a drawing roller and a sheet without providing an independent drive unit for increasing the pressing force between the drawing roller and the sheet.SOLUTION: An image formation device 100 includes a sheet storage device 210 that lifts a sheet placement part 211 that can be freely lifted and lowered with respect to a sheet storage device body 210a using energizing members 212-212, and sheets P placed on the sheet placement part 211 are pressed by a drawing roller 221 which is rotationally driven by a drive unit 240. The image formation device 100 includes a pressing force increasing unit 230 that increases pressing force between the drawing roller 221 and the sheets P using the rotational driving force of the drive unit 240 that rotationally drives the drawing roller 221.SELECTED DRAWING: Figure 3B

Description

The present disclosure relates to image forming apparatuses such as copying machines, multifunction devices, printers, and facsimile machines.

A sheet accommodating device (paper feed cassette) that lifts a sheet loading section that can be raised and lowered with respect to the main body of the sheet accommodating device using a biasing member (a coil spring), and sheets such as recording paper are placed on the sheet loading section. Conventionally, an image forming apparatus is known in which the image forming apparatus is pressed by a pull-in roller that is rotationally driven by a drive unit (drive motor). Here, examples of the pull-in roller include a roller that functions as a pickup roller to which the rotational driving force from the supply roller is transmitted, and a supply roller that also functions as the pickup roller.

In such image forming apparatuses, the coefficient of wear between the feed roller (usually a roller made of rubber material) and the sheet decreases, and the rotating feed roller slips against the sheet, causing a delay in sheet feeding timing. In some cases, feeding errors may occur, such as the sheet not being fed or the sheet not being fed. This is particularly noticeable in low temperature and low humidity environments.

In this case, conventionally, the sliding of the drawing roller against the sheet has been suppressed by increasing the pressing force between the drawing roller and the sheet.

Regarding this point, Patent Document 1 describes a paper feed drive motor that rotationally drives a paper feed roller (feed roller), and a pressure force (pressing force) between the paper feed roller (feed roller) and paper (sheet). A configuration is described in which the pressure contact force of the paper to the paper feed roller is adjusted to maintain an optimum coefficient of friction using a pressure contact force adjustment motor that causes changeable pressure contact and a control unit that operates the pressure contact force adjustment motor. .

Japanese Patent Application Publication No. 10-236685

However, the configuration described in Patent Document 1 requires an independent drive unit to increase the pressing force between the drawing roller and the sheet.

Therefore, the present disclosure provides an image forming apparatus that can increase the pressing force between the drawing roller and the sheet without providing an independent drive unit for increasing the pressing force between the drawing roller and the sheet. The purpose is to

In order to solve the above problems, an image forming apparatus according to an embodiment of the present disclosure includes a sheet storage device that lifts a sheet placement section that can be raised and lowered with respect to a main body of the sheet storage device using a biasing member, An image forming apparatus in which a sheet to be placed is pressed by a pull-in roller that is rotationally driven by a drive section, the sheet being loaded is It is characterized in that it includes a pressing force increasing portion that increases the pressing force between the roller and the sheet.

According to the present disclosure, it is possible to increase the pressing force between the drawing roller and the sheet without providing an independent drive unit for increasing the pressing force between the drawing roller and the sheet.

1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment. FIG. 2 is a perspective view of the sheet storage device viewed diagonally from above and to the right on the front side. FIG. 3 is a perspective view of the sheet storage device with the sheet feeding device main body removed, as seen diagonally from above and to the left on the front side. FIG. 2 is a perspective view schematically showing the sheet accommodating device and a part of the pressing force increasing portion according to the first embodiment as viewed diagonally from above on the back side. FIG. 3B is a perspective view schematically showing a partially enlarged pressing force increasing portion shown in FIG. 3A. FIG. 3 is a front view schematically showing an enlarged state in which the displacement portion is located at a non-displacement position in the configuration of the pressing force increasing portion on the image forming apparatus main body side according to the first embodiment. FIG. 3 is a front view schematically showing an enlarged state in which the displacement portion is located at a displacement position in the configuration of the pressing force increasing portion on the image forming apparatus main body side according to the first embodiment. FIG. 7 is a perspective view schematically showing a partially enlarged pressing force increasing portion according to the second embodiment. FIG. 7 is a front view schematically showing an enlarged view of the configuration of the pressing force increasing unit on the image forming apparatus main body side according to the second embodiment. FIG. 7 is a perspective view schematically showing a partially enlarged pressing force increasing portion according to a third embodiment.

Embodiments according to the present disclosure will be described below with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Overall configuration of image forming apparatus]
FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus 100 according to the present embodiment. In the figure, the symbol X represents the left-right direction when viewed from the front of the image forming apparatus 100, and the symbols X1 and X2 represent the left side (one side) and the right side (the other side), respectively. The symbol Y represents the depth direction perpendicular to the left-right direction X, and the symbols Y1 and Y2 represent the front side (one side, operation side) and the back side (the other side), respectively. The symbol Z represents the vertical direction (up and down direction).

The image forming apparatus 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function. The image forming apparatus 100 includes an image forming apparatus main body 101 and an image reading device 102. The image forming apparatus main body 101 includes a sheet supply section 110, an image forming section 120, and a sheet discharge section 130.

The image reading device 102 reads an image on a document, and includes a document transport section 102a and a document reading section 102b. The image reading device 102 reads the image of the original G with the original reading unit 102b while transporting the original G with the original transporting unit 102a, or reads the original G placed on the original table of the original reading unit 102b as an original. It is scanned and read by the reading unit 102b. The sheet supply section 110 supplies a sheet P such as recording paper toward the image forming section 120 . The image forming section 120 forms (prints) an image on the sheet P sent from the sheet supply section 110 based on the image data. The sheet discharge section 130 discharges the sheet P on which an image has been formed in the image forming section 120.

The image forming section 120 includes an optical scanning device 1, a developing device 2, a photoconductor drum 3 (photoconductor), a drum cleaning device 4, a charger 5, an intermediate transfer device 6, a fixing device 7, and an output tray 8 (in-body output tray). ).

The image forming apparatus 100 generates an image corresponding to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (for example, black). data is handled. The image forming section 120 of the image forming apparatus 100 is provided with four developing devices 2, a photosensitive drum 3, a drum cleaning device 4, and a charger 5 in order to form four types of toner images. , cyan, magenta, and yellow, and constitute four image stations Pa, Pb, Pc, and Pd.

The optical scanning device 1 exposes the surface of the photoreceptor drum 3 to form an electrostatic latent image. The developing device 2 develops the electrostatic latent image on the surface of the photoreceptor drum 3 to form a toner image on the surface of the photoreceptor drum 3 . The drum cleaning device 4 removes and collects residual toner on the surface of the photoreceptor drum 3. The charger 5 uniformly charges the surface of the photoreceptor drum 3 to a predetermined potential. Through the series of operations described above, toner images of each color are formed on the surface of each photoreceptor drum 3.

The intermediate transfer device 6 includes an intermediate transfer roller 61, an endless intermediate transfer belt 62, a transfer drive roller 63, a transfer driven roller 64, and a belt cleaning device 65. Four intermediate transfer rollers 61 are provided inside the intermediate transfer belt 62 so as to form four types of toner images corresponding to each color. The intermediate transfer roller 61 transfers the toner images of each color formed on the surface of the photoreceptor drum 3 to an intermediate transfer belt 62 that rotates in the direction of arrow M.

The intermediate transfer belt 62 is stretched around a transfer drive roller 63 and a transfer driven roller 64 . In the image forming apparatus 100, the toner images of each color formed on the surface of each photoreceptor drum 3 are sequentially transferred and overlapped to form a color toner image on the surface of the intermediate transfer belt 62.

A nip portion is formed between the transfer roller 9a of the secondary transfer device 9 and the intermediate transfer belt 62, and the sheet P conveyed through the sheet conveyance path 11 is sandwiched in the nip portion and conveyed. When the sheet P passes through the nip portion, the toner image on the surface of the intermediate transfer belt 62 is transferred to the sheet P, and the sheet P is conveyed to the fixing device 7 . The belt cleaning device 65 removes and collects waste toner remaining on the surface of the intermediate transfer belt 62 without being transferred to the sheet P.

The fixing device 7 includes a fixing roller 7a and a pressure roller 7b that rotate with the sheet P sandwiched therebetween. The fixing device 7 fixes the toner image on the sheet P by sandwiching the sheet P on which the toner image has been transferred between the fixing roller 7a and the pressure roller 7b, and applying heat and pressure to the sheet P.

The sheet supply unit 110 includes a sheet storage device 210 (paper feed cassette) and a sheet supply device 220.

The sheet storage device 210 can be attached to and detached from the image forming apparatus main body 101 along the attachment and detachment direction S (the pull-out direction S1 and the insertion direction S2). The sheet storage device 210 is for storing sheets P used for image formation. In this example, the sheet storage device 210 is provided below the image forming section 120. In this example, the sheet supply section 110 has one stage, but is not limited to this, and may have two or more stages. Further, although the sheet supply unit 110 is provided in the image forming apparatus main body 101, it may be provided in a paper feeding desk device or a large capacity paper feeding device that can hold more than 500 sheets. In this case, the paper feeding desk device main body and the large capacity paper feeding device main body constitute the image forming apparatus main body 101.

The sheet storage device 210 includes a sheet placement section 211 (rotating plate in this example). The sheet P is placed on the sheet placement section 211 . The sheet supply device 220 supplies the sheet P placed on the sheet placement section 211 to the sheet conveyance path 11 in a predetermined supply direction E. The drawing roller 221 of the sheet supply device 220 pulls out the sheet P from the sheet placement section 211 and supplies it to the supply roller 222 . In this example, the drawing roller 221 functions as a pickup roller to which rotational driving force from the supply roller 222 is transmitted. The supply roller 222 pinches the sheet P drawn in by the drawing roller 221 between it and the separation roller 223 and supplies it to the sheet conveyance path 11 . The sheet P supplied to the sheet conveyance path 11 is conveyed to the discharge roller 12 via the secondary transfer device 9 and the fixing device 7, and is discharged to the discharge tray 8 in the sheet discharge section 130.

In the sheet conveyance path 11, a conveyance roller 13, a registration roller 14, and a discharge roller 12 are arranged. The conveyance roller 13 urges the sheet P to be conveyed. The registration rollers 14 temporarily stop the sheet P and align the leading ends of the sheet P. The registration rollers 14 transport the once stopped sheet P in accordance with the timing of the color toner image on the intermediate transfer belt 62. The color toner image on the intermediate transfer belt 62 is transferred onto the sheet P at the nip between the intermediate transfer belt 62 and the transfer roller 9a.

Further, when forming an image not only on the front side of the sheet P but also on the back side, the image forming apparatus 100 conveys the sheet P in the opposite direction from the discharge roller 12 to the sheet reversing conveyance path 11r. The image forming apparatus 100 reverses the front and back sides of the sheet P conveyed in the opposite direction by the discharge roller 12 in the sheet reversing conveyance path 11r, and guides the sheet P to the registration rollers 14 again. Further, the image forming apparatus 100 forms an image on the back side of the sheet P guided by the registration rollers 14 in the same manner as on the front side, and carries it out to the discharge tray 8 . Note that the sheet P is conveyed along the sheet conveyance path 11 in the rotation axis direction (depth direction Y) of the photoconductor drum 3 with the center of the photoconductor drum 3 as a reference (center reference).

[Sheet supply section]
FIG. 2A is a perspective view of the sheet storage device 210 viewed diagonally from the upper right side of the front side. FIG. 2B is a perspective view of the sheet storage device 210 with the sheet feeding device main body 220a removed, as viewed diagonally from the upper left on the front side. FIG. 3A is a perspective view schematically showing the sheet accommodating device 210 and a part of the pressing force increasing portion 230 according to the first embodiment as viewed diagonally from above on the back side. FIG. 3B is a perspective view schematically showing a partially enlarged pressing force increasing portion 230 shown in FIG. 3A. 4A and 4B are enlarged views of the state in which the displacement portion 238 is located at the non-displacement position and the displacement position in the configuration of the image forming apparatus main body 101 side of the pressing force increasing portion 230 according to the first embodiment, respectively. It is a front view showing typically.

The image forming apparatus 100 includes a sheet storage device 210, a sheet feeding device 220, and a pressing force increasing section 230. The sheet storage device 210 includes a sheet placement section 211 and one or more (four in this example) biasing members 212 to 212 (coiled springs in this example). The sheet placement section 211 is movable up and down with respect to the sheet storage device main body 210a. In this example, the sheet placement unit 211 is provided in the sheet storage device main body 210a so as to be rotatable (freely rotatable) around the rotation axis α along the depth direction Y (with the rotation axis 211a as a fulcrum). There is. The sheets P are stored in the sheet storage device main body 210a, and the sheets P are placed (stacked) on the sheet placement section 211. The sheet placing section 211 is urged upward by urging members 212 to 212, and the sheet P placed on the sheet placing section 211 is supplied in the feeding direction E. The biasing members 212 to 212 bias the sheet placement section 211 upward.

As shown in FIG. 2B, the sheet feeding device 220 includes a drawing roller 221 (roller made of rubber material), a feeding roller 222 (sheet feeding roller), and a separating member [separating roller or separating pad (in this example, a separating roller). 223)] (see FIG. 2A), a support member 224, and a supply drive transmission mechanism 225. In this example, the sheet supply device 220 is provided in the sheet storage device 210. Note that the present invention is not limited thereto, and the sheet feeding device 220 may be provided in the image forming apparatus main body 101 in the image forming apparatus 100.

The drawing roller 221 draws the sheet P placed on the sheet placing section 211. The drawing roller 221 contacts the upper surface of the sheet P placed on the sheet placement section 211 and supplies the sheet P in the feeding direction E. The pull-in roller 221 rotates and pulls in the uppermost sheet P among the sheets P placed on the sheet placement section 211 of the sheet storage device 210 while pressing it. Further, the drawing roller 221 supplies the uppermost sheet P placed (stacked) on the sheet placement section 211 one by one in the feeding direction E. The supply roller 222 transports the sheets P brought in by the drawing roller 221 one by one together with the separation roller 223 in the supply direction E toward the sheet transport path 11 (see FIG. 1). Separation roller 223 is disposed opposite supply roller 222 . The separation roller 223 restricts the conveyance of the second and subsequent sheets P from the top among the sheets P placed on the sheet placement section 211 in the supply direction E.

The support member 224 supports the rotation shaft 221a (see FIG. 2B) of the drawing roller 221 along the depth direction Y so as to be rotatable around the rotation axis. Further, the support member 224 rotates around a rotation axis 222a (see FIGS. 2B, 3A, and 3B) along the depth direction Y of the supply roller 222 on the downstream side of the intake roller 221 in the supply direction E. Support freely. The support member 224 is provided in the sheet supply apparatus main body 220a so as to be able to freely rotate around the rotation axis (centering on the rotation shaft 222a) with respect to the rotation shaft 222a of the supply roller 222. The supply roller 222 receives rotational driving force from a drive unit 240 (drive motor) (see FIGS. 3A and 3B) via a conveyance drive transmission mechanism 240a (see FIGS. 3A and 3B). The supply drive transmission mechanism 225 includes a gear train or a timing pulley and a timing belt (in this example, as shown in FIG. 2B, a gear train consisting of a driving gear 225a, an intermediate gear 225b, and a driven gear 225c). The supply drive transmission mechanism 225 transmits the rotational driving force sent to the supply roller 222 to the drawing roller 221. Thereby, the drive unit 240 can rotationally drive the drawing roller 221.

In the sheet storage device 210 described above, the sheet placement section 211 is lifted by the biasing members 212 to 212. The sheet P placed on the sheet placement section 211 is pressed by a pull-in roller 221. The drawing roller 221 is rotationally driven by a driving section 240.

Note that, as the pull-in roller 221, a roller that functions as a pickup roller to which the rotational driving force from the supply roller 222 is transmitted was used, but the pull-in roller 221 that functions as a pickup roller and the supply drive transmission mechanism 225 are removed, The supply roller 222 may also function as a pickup roller. In this case, the supply roller 222, which also functions as a pickup roller, acts as a pull-in roller.

(First embodiment)
The pressing force increasing unit 230 is configured to increase the pressing force between the drawing roller 221 and the sheet P by using the rotational driving force of the drive unit 240 that rotationally drives the drawing roller 221 (in this example, the urging member 212 212). That is, the drive unit 240 that rotationally drives the drawing roller 221 also drives the pressing force increasing unit 230.

In the present embodiment, the pressing force increasing unit 230 includes a base 231 provided on the sheet storage device main body 210a so as to be movable in the vertical direction Z, and a lifting mechanism 232 (see FIGS. 3A and 3B) that raises the base 231. It is equipped with The biasing members 212 to 212 are arranged between the bottom surface 210b of the sheet placement section 211 and the base 231.

Specifically, the side plates 214 and 215 on both sides in the depth direction Y of the sheet storage device main body 210a are provided with guide portions 214a and 215a (long through holes) through which the insertion members 232c and 232c are inserted. The guide portions 214a and 215a extend in the vertical direction Z. The base 231 is a plate-shaped member that extends in the depth direction Y along the bottom surface 210b (see FIGS. 2A and 3A) of the sheet storage device main body 210a. This makes it possible to easily arrange the biasing members 212 to 212 between the bottom surface 210b of the sheet placement section 211 and the base 231.

The lifting mechanism 232 includes a pair of rack gears 232a, 232a, and a pair of pinion gears 232b, 232b that mesh with the pair of rack gears 232a, 232a, respectively.

The insertion members 232c and 232c are fixed to both side surfaces of the base 231 in the depth direction Y while being inserted into the guide portions 214a and 215a of the sheet storage device main body 210a. The insertion members 232c and 232c protrude outward in the depth direction Y from the side plates 214 and 215 on both sides. The pair of rack gears 232a, 232a are fixed at their lower ends to protrusions that protrude outward from the side plates 214, 215 of the insertion members 232c, 232c. Thereby, the base portion 231 can be made movable in the vertical direction Z with respect to the sheet storage device main body 210a.

A rotating shaft 232b1 is installed on the side plates 214 and 215 of the sheet storage device main body 210a. The rotating shaft 232b1 is rotatably supported at a predetermined position in the vertical direction Z by the side plates 214 and 215 on both sides. The pair of pinion gears 232b, 232b are fixed to both ends of the rotating shaft 232b1 that protrude outward from the side plates 214, 215, respectively.

In the lifting mechanism 232 configured in this way, by rotating the pinion gear 232b on the back side Y2 (rear side) in a predetermined direction (counterclockwise in FIGS. 3A and 3B), the pinion gear 232b on the front side Y1 (front side) is rotated. 232b also rotates, and both rack gears 232a, 232a move upward. As a result, the base portion 231 can be raised, and the urging force of the urging members 212 to 212 applied to the sheet placement portion 211 can be increased. Therefore, the pressing force between the drawing roller 221 and the sheet P can be increased. can be increased.

The raising mechanism 232 raises the base 231 in conjunction with the rotation of the drive unit 240 that rotationally drives the drawing roller 221 . The drive unit 240 is provided in the image forming apparatus main body 101 (main body frame).

The pressing force increasing section 230 further includes a switching mechanism 2330 that transmits the rotational driving force from the driving section 240 to the rack gear 232a on the back side Y2 (rear side). The switching mechanism 2330 is provided on the image forming apparatus main body 101 side.

As shown in FIG. 3B, the switching mechanism 2330 includes a gear train 233 that includes a plurality of (seven in this example) gears (first gear 233a to seventh gear 233g) and a plurality of gears (in this example, seven) along the depth direction Y. (6) support shafts (first support shaft 2331 to sixth support shaft 2336).

Further, the pressing force increasing unit 230 further includes a torque limiter 2337 that regulates the amount of increase in the pressing force between the drawing roller 221 and the sheet P. Torque limiter 2337 is provided in switching mechanism 2330.

The first gear 233a is fixed to a first support shaft 2331 connected to the drive section 240. The second gear 233b meshes with the first gear 233a and is fixed to a second support shaft 2332 rotatably supported by the image forming apparatus main body 101.

The third gear 233c meshes with the second gear 233b and is rotatably supported by a third support shaft 2333 fixed to the image forming apparatus main body 101. The fourth gear 233d meshes with the third gear 233c and is rotatably supported by a fourth support shaft 2334.

The fifth gear 233e meshes with the fourth gear 233d and is rotatably supported by a fifth support shaft 2335 fixed to the image forming apparatus main body 101. The sixth gear 233f is provided on a sixth support shaft 2336 that meshes with the fifth gear 233e and is rotatably supported by the image forming apparatus main body 101 via a torque limiter 2337. The seventh gear 233g is fixed to the sixth support shaft 2336, and meshes with the pinion gear 232b when the sheet storage device 210 is attached to the image forming apparatus main body 101.

The torque limiter 2337 connects the sixth gear 233f and the sixth support shaft 2336 until a predetermined set torque, and connects the sixth gear 233f and the sixth support shaft 2336 when the predetermined set torque is exceeded. Separate. Therefore, the torque limiter 2337 transmits the rotational driving force from the sixth gear 233f to the pinion gear 232b via the sixth support shaft 2336 and the seventh gear 233g up to a predetermined set torque, while exceeding the predetermined set torque. Then, transmission of the rotational driving force from the sixth gear 233f to the pinion gear 232b is stopped.

In this example, the torque limiter 2337 is provided between the sixth gear 233f and the sixth support shaft 2336, but is not limited thereto, and may be provided in any drive transmission section of the switching mechanism 2330. Can be done.

Furthermore, a convex engaging portion 2332a is provided at the end of the second support shaft 2332 on the front side Y1 in the depth direction Y. A concave engagement portion 222b that is engaged with the convex engagement portion 2332a is provided at the end of the rotation shaft 222a of the supply roller 222 on the back side Y2 in the depth direction Y. Note that the convex engaging portion 2332a may be a concave engaging portion, and the concave engaging portion 222b may be a convex engaging portion. The concave engaging portion 222b engages with the convex engaging portion 2332a when the sheet storage device 210 is attached to the image forming apparatus main body 101. At this time, the first support shaft 2331, the first gear 233a, the second gear 233b, the second support shaft 2332, the convex engagement part 2332a, the concave engagement part 222b, and the rotating shaft 222a constitute the transport drive transmission mechanism 240a. , transmits the rotational driving force from the drive unit 240 to the supply roller 222.

In this embodiment, the upward distance d1 (see FIG. 3B) of the base 231 is the moving distance d2 (see FIG. 3B) between when the sheet placement section 211 is located at the upper limit position P1 and when it is located at the lower limit position P2. (see). Here, the sheet placement section 211 is regulated at an upper limit position P1 and a lower limit position P2. The sheet placing portion 211 is locked at the lower limit position by a locking portion 216 (see FIG. 2A) provided on the sheet storage device main body 210a. At this time, the user can place the sheets P to P on the sheet placement section 211 in the sheet storage device main body 210a. The sheet placement section 211 is unlocked by the locking section 216 at the lower limit position when the sheet storage device 210 is attached to the image forming apparatus main body 101 . At this time, the sheet placing portion 211 is raised from the lower limit position P2 by the urging force of the urging members 212 to 212.

In the present embodiment, the raising mechanism 232 lowers the base portion 231 when the sheet P passes a downstream roller (in this example, the supply roller 222) downstream of the intake roller 221 in the supply direction E of the sheet P. .

In this embodiment, the pressing force increasing section 230 includes a displacement section 238 (see FIGS. 4A and 4B) and a switching mechanism 2330 (see FIG. 4A). The displacement portion 238 is pushed by the sheet P when the sheet P passes the downstream roller (222), and moves from a non-displaced position (the position shown in FIG. 4A) to a displaced position (the position pushed downstream shown in FIG. 4B). ) is displaced. The switching mechanism 2330 is capable of selectively switching between a transmission state in which the rotational driving force is transmitted from the drive unit 240 to the lifting mechanism 232 and a blocking state in which transmission of the rotational driving force from the driving unit 240 to the lifting mechanism 232 is interrupted. ing.

The displacement section 238 puts the switching mechanism 2330 in the transmission state when it is in the non-displacement position (see FIG. 4A), and puts the switching mechanism 2330 in the blocking state when it is displaced in the displacement position (see FIG. 4B). .

In this embodiment, when the rotational driving force from the drive section 240 to the lifting mechanism 232 is cut off, the base section 231 descends (see FIG. 4B).

In this embodiment, the switching mechanism 2330 includes a gear train 233 consisting of a plurality of gears (233a to 233g) that transmits rotational driving force from the drive section 240 to the raising mechanism 232.

In the gear train 233, when the displacement portion 238 is displaced to the displacement position, one of the gears (fourth gear 233d in this example) among the plurality of gears (233a to 233g) is disengaged, and the displacement portion 238 is displaced to the displacement position. By returning to the non-displaced position, one of the gears (233d) returns from the disengaged state to the engaged state.

In this embodiment, the lifting mechanism 232 is provided on the sheet storage device main body 210a side.

<Displacement part>
Specifically, the displacement section 238 is provided on the image forming apparatus main body 101 side. As shown in FIGS. 4A and 4B, the displacement portion 238 includes a swing member 238a, a slide member 238b, a contact portion 238c, a biasing member 238d (a coil spring in this example), and a rotation shaft 238e. , an arm portion 238f, and a concave engaging portion 238g (see FIGS. 3A and 3B).

The swinging member 238a is swingably supported by a third support shaft 2333 at one end, and has a fourth support shaft 2334 fixed at the other end. Thereby, the fourth gear 233d (movable gear) rotatably supported by the fourth support shaft 2334 can be swung around the third support shaft 2333. Therefore, when the displacement section 238 is located at the non-displacement position (see FIG. 4A), the fourth gear 233d can be brought into mesh with the fifth gear 233e, and when it is located at the displacement position (see FIG. 4B). ), the fourth gear 233d can be brought out of mesh with the fifth gear 233e.

The slide member 238b is rotatably supported by a fourth support shaft 2334 at one end, and is provided with an abutting portion 238c at the other end. The contact portion 238c is erected from the slide member 238b toward the front side Y1 in the depth direction Y. Further, on the back side Y2 in the depth direction Y of the slide member 238b, an insertion portion 238b1 (projection portion) is provided to protrude toward the back side Y2. The image forming apparatus main body 101 (main body frame) is provided with a guide portion 101a (long through hole) through which the insertion portion 238b1 (protrusion) is inserted. The guide portion 101a extends in the direction of the movement trajectory of the insertion portion 238b1. Thereby, the slide member 238b can be freely slid with respect to the image forming apparatus main body 101. The biasing member 238d biases the slide member 238b in the direction in which the fourth gear 233d meshes with the fifth gear 233e.

The rotation shaft 238e is rotatably supported by the image forming apparatus main body 101 (main body frame). The arm portion 238f is fixed to the rotation shaft 238e such that the tip portion thereof contacts the contact portion 238c of the slide member 238b. Thereby, the arm portion 238f can slide the slide member 238b along the guide portion 101a by swinging around the rotation axis 238e. Therefore, the displacement portion 238 can be positioned at a non-displacement position (see FIG. 4A) and a displacement position (see FIG. 4B), and in turn, the fourth gear 233d can be placed in an engaged state and a disengaged state with the fifth gear 233e. You can switch to

A concave engaging portion 238g (see FIGS. 3A and 3B) is provided at the end of the front side Y1 in the depth direction Y of the rotating shaft 238e, and a convex engaging portion 239c (see FIG. 3B) of the rotating mechanism 239 is provided. 3A, 3B). Note that the concave engaging portion 238g may be a convex engaging portion, and the convex engaging portion 239c may be a concave engaging portion.

<Rotation mechanism>
As shown in FIG. 3B, the rotation mechanism 239 includes a rotation shaft 239a, an actuator portion 239b, a convex engagement portion 239c (see FIG. 3B), and a biasing member 239d (a coiled spring in this example). We are prepared.

The rotation shaft 239a is rotatably supported by the sheet storage device main body 210a (main body frame) around a rotation axis along the depth direction Y. The conveyance guide portion 210c of the sheet storage device main body 210a is provided with a through hole 210c1 through which the actuator portion 239b is inserted on the downstream side of the drawing roller 221 in the feeding direction E of the sheet P. The actuator section 239b is fixed to a rotation shaft 239a. The tip end of the actuator portion 239b protrudes from the through hole 210c1 in the sheet storage device main body 210a. A convex engagement portion 239c is provided at the end of the rotation shaft 239a on the back side Y2 in the depth direction Y. The convex engaging portion 239c engages with the concave engaging portion 238g on the rotation shaft 238e when the sheet storage device 210 is attached to the image forming apparatus main body 101. The biasing member 239d biases the actuator portion 239b in a direction in which the actuator portion 239b is positioned at a protruding position where the actuator portion 239b protrudes from the sheet storage device main body 210a. Thereby, the actuator portion 239b is located at the protruding position when the sheet P is not in contact with the actuator portion 239b. At this time, the displacement portion 238 is located at a non-displacement position (see FIG. 4A), and the fourth gear 233d remains in mesh with the fifth gear 233e. On the other hand, when the seat P comes into contact with the actuator section 239b, the actuator section 239b swings about the rotation shaft 239a and is located at the retracted position. At this time, the arm portion 238f swings about the rotation shaft 238e via the rotation shaft 239a, the convex engagement portion 239c, the concave engagement portion 238g, and the rotation shaft 238e on one side R1 in the swinging direction R (see FIG. 4B). (in a clockwise direction). Further, the swing member 238a swings to one side R1 in the swing direction R around the third support shaft 2333 via the contact portion 238c, the slide member 238b, and the fourth support shaft 2334. As a result, the displacement portion 238 is displaced to the displacement position (see FIG. 4B), and the meshing state of the fourth gear 233d with the fifth gear 233e is released.

<Operation of pressing force increasing part>
In the pressing force increasing section 230 described above, before the sheet P passes the downstream roller (in this example, the supply roller 222), the actuator section 239b is positioned at the protruding position by the biasing member 239d, and the swinging member 238a is A fourth gear 233d biased by a biasing member 238d engages with a fifth gear 233e (see FIG. 4A).

At this time, when the print job (image forming operation) is started by the user's operation and the rotational drive of the drive unit 240 starts, the rotational driving force from the drive unit 240 is applied to the first support shaft 2331, the first gear 233a, the second It is transmitted to the supply roller 222 (see FIG. 2B) via the gear 233b, the second support shaft 2332, the convex engagement portion 2332a, the concave engagement portion 222b, and the rotating shaft 222a, and the supply roller 222 rotates. Furthermore, the rotational driving force from the supply roller 222 is transmitted to the intake roller 221 via the supply drive transmission mechanism 225 (see FIG. 2B), and the intake roller 221 rotates. Then, the uppermost sheet P of the sheets P to P stacked on the sheet stacking section 211 in the sheet storage device main body 210a is brought in, and the sheets P begin to be fed in the feeding direction E.

On the other hand, the rotational driving force from the drive unit 240 is transmitted from the first gear 233a to the rack gear 232a via the seventh gear 233g and pinion gear 232b, and the rack gear 232a moves upward. Then, the base 231 rises and the lower ends of the biasing members 212 to 212 are pushed up by the base 231, and the biasing force of the biasing members 212 to 212 applied to the sheet placement section 211 begins to increase.

As the drive unit 240 further rotates, the urging force of the urging members 212 to 212 applied to the sheet placement unit 211 increases while the sheet P is supplied in the feeding direction E. As a result, even if the wear coefficient between the pull-in roller 221 and the sheet P decreases, the rotating pull-in roller 221 may slip with respect to the sheet P, causing a delay in the feeding timing of the sheet P, or It is possible to suppress feeding defects such as failure to feed. This is particularly effective in low temperature and low humidity environments.

When the drive unit 240 is further driven to rotate and exceeds a predetermined set torque at the torque limiter 2337, the sixth support shaft 2336 idles relative to the seventh gear 233g. Thereby, it is possible to effectively prevent the urging force of the urging members 212 to 212 applied to the sheet placement portion 211 from increasing too much.

When the actuator part 239b is pressed by the sheet P supplied in the supply direction E by further rotationally driving the drive part 240 and the actuator part 239b is moved from the protruding position to the retracted position, the rotation shaft 239a and the convex engaging part 239c are moved. , the arm portion 238f swings to one side R1 in the swing direction R via the concave engaging portion 238g and the rotation shaft 238e, and the slide member 238b slides upward. Further, the swinging member 238a swings, and the engagement of the fourth gear 233d of the swinging member 238a with the fifth gear 233e is released (see FIG. 4B). Then, the base portion 231 is lowered, and the operation of increasing the urging force of the urging members 212 to 212 applied to the sheet placement portion 211 is stopped.

Further, when the seat P passes the actuator section 239b, the pressure of the seat P against the actuator section 239b is released, and the actuator section 239b is positioned from the retracted position to the protruding position, the arm section 238f is moved to the other side R2 in the swing direction R. (counterclockwise in FIG. 4B), and the slide member 238b slides downward. Further, the swinging member 238a swings to the other side R2 in the swinging direction R, and the fourth gear 233d of the swinging member 238a returns to the meshing state with the fifth gear 233e (see FIG. 4A).

(First embodiment)
As explained above, the pressing force increasing unit 230 increases the pressing force between the drawing roller 221 and the sheet P by using the rotational driving force of the drive unit 240 that rotationally drives the drawing roller 221. An independent drive unit for increasing the pressing force between the drawing roller 221 and the sheet P is not required. Further, a control configuration for increasing the pressing force between the drawing roller 221 and the sheet P is not required. The pressing force increasing portion 230 can increase the pressing force between the drawing roller 221 and the sheet P.

Therefore, the pressing force between the drawing roller 221 and the sheet P can be increased without providing an independent drive unit for increasing the pressing force between the drawing roller 221 and the sheet P. Furthermore, there is no need to provide a control structure for increasing the pressing force between the drawing roller 221 and the sheet P.

(First embodiment-1)
Further, the pressing force increasing unit 230 includes a base 231 provided on the sheet storage device main body 210a so as to be movable in the vertical direction Z, and a lifting mechanism 232 that raises the base 231. The raising mechanism 232 is disposed between the bottom surface 210b of the placing part 211 and the base part 231, and lifts the base part 231 in conjunction with the rotation of the driving part 240 that rotationally drives the drawing roller 221. The urging force of the urging members 212 to 212 applied to the portion 211 can be increased. This makes it possible to reliably increase the pressing force between the drawing roller 221 and the sheet P, although the configuration is simple.

In the present embodiment, the rising distance d1 of the base 231 is smaller than the moving distance d2 between when the sheet placing section 211 is located at the upper limit position P1 and when it is located at the lower limit position P2, so that the sheet The moving distance d2 of the placing portion 211 can be made larger than the rising distance d1 of the base portion 231, and the urging force of the urging members 212 to 212 can be applied to the sheet placing portion 211 with a corresponding margin.

(First embodiment-2)
By the way, if the pressing force between the drawing roller 221 and the sheet P is increased too much, too much load will be applied to the drawing roller 221. In addition, feeding defects such as double feeding may occur, and/or the life of the drawing roller 221 is likely to be shortened. This is particularly noticeable in high temperature and high humidity environments.

In this regard, in the present embodiment, the pressing force increasing unit 230 includes a torque limiter 2337 that regulates the amount of increase in the pressing force between the drawing roller 221 and the sheet P. A limit can be set on the amount of increase in the pressing force, thereby reducing the load on the drawing roller 221. In addition, it is possible to effectively prevent feeding defects such as double feeding and/or shortening the life of the drawing roller 221. This is particularly effective in high temperature and high humidity environments.

(First embodiment-3)
By the way, when the sheet P reaches the downstream roller (222), the sheet P is sent by the downstream roller (222), so there is no need to perform an increasing operation to increase the pressing force between the drawing roller 221 and the sheet P. do not have. Therefore, if the sheet P continues to perform an increasing operation even after passing through the downstream roller (222) on the downstream side, the increasing operation will be wasted.

In this regard, in the present embodiment, when the sheet P passes the downstream roller (222), the base 231 lowers, so that when the sheet P is sent by the downstream roller (222), the raising mechanism 232 It is possible to avoid performing an increasing operation that increases the pressing force between the drawing roller 221 and the sheet P, thereby eliminating waste in the increasing operation.

(First embodiment-4)
In this embodiment, the switching mechanism 2330 is placed in the transmission state when the displacement section 238 is located at the non-displacement position, and the switching mechanism 2330 is placed in the blocking state when the displacement section 238 is displaced to the displacement position. In a state where the sheet P is sent by the downstream roller (222), it is possible to avoid performing an increasing operation that increases the pressing force between the pull-in roller 221 and the sheet P, thereby eliminating waste of the increasing operation. be able to.

(First embodiment-5)
In this embodiment, by cutting off the rotational driving force from the drive unit 240 to the lifting mechanism 232, the base 231 can be reliably lowered. The increasing operation of increasing the pressing force can be reliably stopped.

(First embodiment-6)
In this embodiment, the switching mechanism 2330 includes a gear train 233 consisting of a plurality of gears (233a to 233g) that transmits rotational driving force from the drive section 240 to the raising mechanism 232.

The gear train 233 is driven by disengaging any one gear (fourth gear 233d in this example) among the plurality of gears (233a to 233g) by displacing the displacement portion 238 to the displacement position. A configuration for canceling the transmission of rotational driving force from the portion 240 to the lifting mechanism 232 can be easily realized. Furthermore, when the displacement section 238 returns to the non-displacement position, one of the gears (233d) returns to the meshing state, so that the gear train 233 is in a state where rotational driving force is transmitted from the drive section 240 to the lifting mechanism 232. It is possible to easily realize a configuration for returning the data.

(First embodiment-7)
In the present embodiment, since the lifting mechanism 232 is provided on the image forming apparatus main body 101 side, the structure of the lifting mechanism 232 can be easily realized in the image forming apparatus main body 101.

(Second embodiment)
FIG. 5 is a perspective view schematically showing a partially enlarged pressing force increasing portion 230A according to the second embodiment. FIG. 6 is a front view schematically showing an enlarged configuration of the pressing force increasing section 230A on the image forming apparatus main body 101 side according to the second embodiment.

A pressing force increasing section 230A according to the second embodiment differs from the pressing force increasing section 230A according to the first embodiment in that a sheet passage detecting section 230a and an electromagnetic clutch 230b are provided in place of the displacement section 238.

In the second embodiment, members having the same configuration as those in the first embodiment are denoted by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, the image forming apparatus includes a control section 140. The pressing force increasing section 230A includes a sheet passage detection section 230a (sensor) and an electromagnetic clutch 230b instead of the displacement section 238. The sheet passage detection section 230a is provided in the sheet storage apparatus main body 210a, and the control section 140 and the electromagnetic clutch 230b are provided in the image forming apparatus main body 101.

The control unit 140 controls the entire image forming apparatus 100. The control unit 140 includes a processing unit 141 and a storage unit 142. The processing unit 141 is composed of a microcomputer such as a CPU. The storage unit 142 includes nonvolatile memory such as ROM, and volatile memory such as RAM. The control unit 140 controls the operation of various components by having the processing unit 141 load a control program previously stored in the ROM of the storage unit 142 onto the RAM of the storage unit 142 and execute it.

The sheet passage detection unit 230a detects whether the sheet P is passing through the downstream roller (222) (see FIG. 2B). The sheet passage detection section 230a is electrically connected to the input system of the control section 140, and transmits to the control section 140 a signal indicating whether or not the sheet P has passed the downstream roller (222).

The electromagnetic clutch 230b is capable of switching between a transmission state in which the rotational driving force is transmitted from the drive unit 240 to the lifting mechanism 232 and a blocking state in which transmission of the rotational driving force from the driving unit 240 to the lifting mechanism 232 is interrupted. The electromagnetic clutch 230b is electrically connected to the output system of the control section 140, and is turned on and off by an instruction signal from the control section 140.

When the control unit 140 determines that the sheet P has not passed the downstream roller (222) based on the detection result of the sheet passage detection unit 230a, the control unit 140 puts the electromagnetic clutch 230b into a transmission state so that the sheet P does not pass through the downstream roller (222). When it is determined that the vehicle has passed the roller (222), the electromagnetic clutch 230b is set to the disconnected state.

Specifically, the sheet passage detection section 230a is a light transmission type detection section (photosensor), and includes a light emitting section 230a1 that emits light and a light receiving section 230a2 that receives light from the light emitting section 230a1. There is. Further, the actuator section 239b is provided with a detection piece 239b1. When the actuator section 239b is located at the protruding position, the detection piece 239b1 allows light to pass between the light emitting section 230a1 and the light receiving section 230a2 of the sheet passage detection section 230a. On the other hand, when the actuator section 239b is located at the retracted position, the detection piece 239b1 blocks light between the light emitting section 230a1 and the light receiving section 230a2 of the sheet passage detection section 230a. Thereby, the sheet passage detection section 230a can detect whether or not the sheet P is passing through the actuator section 239b. In this example, a light transmission type detection section is used as the sheet passage detection section 230a, but the present invention is not limited thereto, and a switch type detection section having an actuator section 239b may be used.

The electromagnetic clutch 230b connects the sixth gear 233f and the sixth support shaft 2336 when it is turned on, and disconnects the sixth gear 233f and the sixth support shaft 2336 when it is turned off. Therefore, when the electromagnetic clutch 230b is turned on, the rotational driving force from the sixth gear 233f is transmitted to the pinion gear 232b via the sixth support shaft 2336 and the seventh gear 233g, while the electromagnetic clutch 230b is turned off. Then, the transmission of the rotational driving force from the sixth gear 233f to the pinion gear 232b is stopped. In this example, the electromagnetic clutch 230b is provided between the sixth gear 233f and the sixth support shaft 2336, but the electromagnetic clutch 230b is not limited thereto, and may be provided in any drive transmission section of the switching mechanism 2330. Can be done.

According to the present embodiment, when it is determined that the sheet P has not passed the downstream roller (222) based on the detection result of the sheet passage detection section 230a, the electromagnetic clutch 230b is put into the transmission state, and the sheet P When it is determined that the sheet P is passing through the downstream roller (222), the electromagnetic clutch 230b is set to the disconnected state. It is possible to avoid performing an increasing operation that increases the pressing force with P, thereby eliminating waste of the increasing operation.

(Third embodiment)
FIG. 7 is a perspective view schematically showing a partially enlarged pressing force increasing portion 230B according to the third embodiment.

The pressing force increasing section 230B according to the third embodiment differs from the pressing force increasing section 230 according to the first embodiment in that a displacement section 238 is provided in the sheet storage device main body 210a.

In the third embodiment, members having the same configuration as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the switching mechanism 2330 is provided on the image forming apparatus main body 101 side, and the displacement section 238 is provided on the sheet storage device main body 210a side. The pressing force increasing section 230B includes a displacement transmission mechanism section 230c that transmits the displacement of the displacement section 238 on the sheet storage apparatus main body 210a side to the switching mechanism 2330 on the image forming apparatus main body 101 side.

In this example, the fourth support shaft 2334 is divided into the sheet storage apparatus main body 210a and the image forming apparatus main body 101. The fourth support shaft 2334 on the sheet storage device main body 210a side is provided with a convex engaging portion 239c, and the fourth support shaft 2334 on the image forming apparatus main body 101 side is provided with a concave engaging portion 238g. Note that the concave engaging portion 238g may be a convex engaging portion, and the convex engaging portion 239c may be a concave engaging portion. The displacement transmission mechanism section 230c includes a convex engagement section 239c provided on the fourth support shaft 2334 on the sheet storage apparatus main body 210a side and a concave engagement section provided on the fourth support shaft 2334 on the image forming apparatus main body 101 side. 238g.

Specifically, in the pressing force increasing section 230B according to the third embodiment, the fourth support shaft 2334 of the image forming apparatus main body 101 is connected to the fourth gear 233d and the displacement section 238 in the first embodiment shown in FIGS. 3A to 4B. is divided between. The fourth support shaft 2334 on the fourth gear 233d side remains on the image forming apparatus main body 101 side, and the fourth support shaft 2334 on the displacement part 238 side is fixed to the side plate 215 of the sheet storage device main body 210a. The arm portion 238f that was provided on the rotation shaft 238e of the image forming apparatus main body 101 in the first embodiment is provided on the rotation shaft 239a of the actuator portion 239b. The guide portion 101a provided on the image forming apparatus main body 101 (main body frame) in the first embodiment is provided on the side plate 215 of the sheet storage apparatus main body 210a. The concave engaging portion 238g provided on the rotation shaft 238e of the image forming apparatus main body 101 in the first embodiment is provided on the fourth support shaft 2334 on the image forming apparatus main body 101 side. The convex engaging portion 239c provided on the rotating shaft 239a of the sheet storage device main body 210a in the first embodiment is provided on the fourth support shaft 2334 on the sheet storage device main body 210a side.

The slide member 238b is rotatably supported by a fourth support shaft 2334 at one end, and is provided with an abutting portion 238c at the other end. The contact portion 238c is erected from the slide member 238b toward the back side Y2 in the depth direction Y. Further, on the front side Y1 of the slide member 238b in the depth direction Y, an insertion portion 238b1 (projection portion) is provided to protrude toward the front side Y1. The side plate 215 of the sheet storage device main body 210a is provided with a guide portion 101a (long through hole) through which the insertion portion 238b1 (protrusion) is inserted. The guide portion 101a extends in the direction of the movement trajectory of the insertion portion 238b1. Thereby, the slide member 238b can be slidable with respect to the side plate 215. The biasing member 238d biases the slide member 238b in the direction in which the fourth gear 233d meshes with the fifth gear 233e.

The arm portion 238f is fixed to the rotation shaft 239a such that the tip portion thereof contacts the contact portion 238c of the slide member 238b. Thereby, the arm portion 238f can slide the slide member 238b along the guide portion 101a by swinging around the rotation axis 239a. Therefore, the displacement portion 238 can be located at the non-displacement position and the displacement position, and the fourth gear 233d can be switched between the meshing state and the disengagement state with the fifth gear 233e.

According to this embodiment, the switching mechanism 2330 is provided on the image forming apparatus main body 101 side, the displacement section 238 is provided on the sheet storage device main body 210a side, and the displacement transmission mechanism section 230c is provided on the sheet storage device main body 210a side. By transmitting the displacement of the displacement portion 238 to the switching mechanism 2330 on the image forming apparatus main body 101 side, it is possible to reduce the number of structural members provided on the image forming apparatus main body 101 side among the structural members of the pressing force increasing portion 230B. Thereby, the configuration of the pressing force increasing section 230B on the image forming apparatus main body 101 side can be simplified.

Note that in the first to third embodiments described above, the sheet supply device 220 is provided in the sheet storage device 210, but it may be provided in the image forming apparatus main body 101.

The present disclosure is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely illustrative in all respects, and should not be interpreted in a limiting manner. The scope of the present disclosure is indicated by the claims, and is not restricted in any way by the main text of the specification. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present disclosure.

Reference Signs List 100 Image forming apparatus 101 Image forming apparatus main body 101a Guide section 110 Sheet supply section 140 Control section 141 Processing section 142 Storage section 210 Sheet storage device 210a Sheet storage device main body 211 Sheet placement section 212 Biasing member 214 Side plate 215 Side plate 220 Sheet supply Device 220a Sheet supply device main body 221 Pick-up roller 222 Supply roller 223 Separation roller 224 Support member 225 Supply drive transmission mechanism 230 Pressing force increasing section 230A Pressing force increasing section 230B Pressing force increasing section 230a Sheet passage detection section 230b Electromagnetic clutch 230c Displacement transmission Mechanism section 231 Base section 232 Lifting mechanism 233 Gear train 2330 Switching mechanism 2337 Torque limiter 238 Displacement section 238a Swinging member 238b Slide member 239 Rotating mechanism 239b Actuator section 240 Drive section E Supply direction P Seat P1 Upper limit position P2 Lower limit position S Attachment/removal direction S1 Pulling direction S2 Insertion direction

Claims (10)

The sheet accommodating device includes a sheet accommodating device that lifts a sheet stacking section that can be raised and lowered with respect to a main body of the sheet accommodating device using a biasing member, and the sheet placed on the sheet stacking section is driven to rotate by a drive section. An image forming apparatus that is pressed,
The image forming apparatus further comprises a pressing force increasing section that increases the pressing force between the drawing roller and the sheet by using the rotational driving force of the drive section that rotationally drives the drawing roller. Device. The image forming apparatus according to claim 1,
The pressing force increasing portion includes a base portion provided on the sheet storage device main body so as to be movable in the vertical direction, and a lifting mechanism that raises the base portion,
the biasing member is disposed between the bottom surface of the sheet placement section and the base;
The image forming apparatus is characterized in that the raising mechanism raises the base in conjunction with rotation of the drive unit that rotationally drives the drawing roller. The image forming apparatus according to claim 1,
The image forming apparatus is characterized in that the pressing force increasing section further includes a torque limiter that regulates an amount of increase in the pressing force between the drawing roller and the sheet. The image forming apparatus according to claim 2,
The image forming apparatus is characterized in that the base portion of the raising mechanism lowers when the sheet passes through a downstream roller downstream of the intake roller in the sheet feeding direction. The image forming apparatus according to claim 2,
The pressing force increasing portion is a displacement portion that is pushed by the sheet and displaced from a non-displacement position to a displacement position when the sheet passes through a downstream roller downstream of the intake roller in the sheet supply direction. and a switching mechanism capable of switching between a transmission state in which rotational driving force is transmitted from the drive unit to the lifting mechanism and a cutoff state in which transmission of rotational driving force from the drive unit to the lifting mechanism is interrupted,
The displacement section is characterized in that when located at the non-displacement position, the switching mechanism is placed in the transmission state, and when displaced to the displacement position, the switching mechanism is placed in the blocking state. Image forming device. The image forming apparatus according to claim 2,
The image forming apparatus is characterized in that the base portion is lowered when rotational driving force from the driving portion to the lifting mechanism is cut off. The image forming apparatus according to claim 5,
The switching mechanism includes a gear train consisting of a plurality of gears that transmits rotational driving force from the drive unit to the raising mechanism,
In the gear train, when the displacement part is displaced to the displacement position, any one of the plurality of gears is disengaged, and when the displacement part returns to the non-displacement position, one of the gears is disengaged. An image forming apparatus characterized in that the two gears are configured to return to an engaged state. The image forming apparatus according to claim 2,
The pressing force increasing section includes a sheet passage detecting section that detects whether or not the sheet passes through a downstream roller downstream of the drawing roller in the sheet feeding direction, and a sheet passing detecting section that detects whether or not the sheet passes through a downstream roller downstream of the drawing roller in the sheet feeding direction; an electromagnetic clutch capable of switching between a transmission state in which rotational driving force is transmitted to the mechanism and a cutoff state in which transmission of rotational driving force from the drive section to the lifting mechanism is interrupted;
If it is determined that the sheet has not passed the downstream roller based on the detection result of the sheet passage detection section, the electromagnetic clutch is put into the transmission state, and the sheet passes the downstream roller. The image forming apparatus is characterized in that the electromagnetic clutch is brought into the disconnected state when it is determined that the electromagnetic clutch is present. The image forming apparatus according to claim 2,
The image forming apparatus is characterized in that the lifting mechanism is provided on the sheet storage device main body side. The image forming apparatus according to claim 5,
The switching mechanism is provided on the image forming apparatus main body side, the displacement section is provided on the sheet storage apparatus main body side,
The image forming apparatus is characterized in that the pressing force increasing section includes a displacement transmission mechanism section that transmits the displacement of the displacement section on the sheet storage device main body side to the switching mechanism on the image forming apparatus main body side. .

Images