阅读说明：本技术 供纸装置以及具备其的图像形成装置 (Sheet feeding device and image forming apparatus including the same ) 是由 柴山豪 木村正治 于 2019-07-03 设计创作，主要内容包括：在供纸装置中,即使在载置的纸张的尺寸各不相同的情况下,无需任何手动操作,可对纸张载置台上具有纸张的情况正确地进行检测。在向图像形成装置供给纸张的供纸装置中,载置面上载置纸张的纸张载置台朝向供纸方向下游侧而向下方倾斜。纸张检测部具有以规定压力将所述纸张的顶端向供纸方向上游侧按压的动作片。在纸张载置台的供纸方向上游侧的端部附近配置有限制构件。限制构件限制纸张的向供纸方向上游侧的移动,并具有距纸张载置台的载置面的高度不同的多个限制部。多个限制部配置为随着所述高度朝向所述供纸方向上游侧而变高。(In the paper feeding device, even if the sizes of the paper sheets loaded are different, the paper feeding device can accurately detect the paper sheets on the paper sheet loading platform without any manual operation. In a paper feeding device for feeding paper to an image forming apparatus, a paper placing table on a placing surface of which the paper is placed is inclined downward toward a downstream side in a paper feeding direction. The paper detection unit has an operation piece for pressing the front end of the paper to the upstream side in the paper feeding direction with a predetermined pressure. A regulating member is disposed near an end portion of the paper-sheet-placing table on the upstream side in the paper-feeding direction. The regulating member regulates movement of the sheet upstream in the sheet feeding direction, and has a plurality of regulating portions having different heights from the mounting surface of the sheet mounting table. The plurality of regulating portions are arranged so as to increase in height as the height increases toward the upstream side in the paper feeding direction.)

1. A sheet feeding device that feeds a sheet to an image forming apparatus, the sheet feeding device comprising:

a sheet mounting table having a mounting surface on which a sheet is mounted and which is inclined downward toward a downstream side in a sheet feeding direction in which the sheet is fed to the image forming apparatus;

a sheet detecting section having an operating piece for pressing a downstream end of the sheet in a sheet feeding direction toward an upstream side in the sheet feeding direction at a predetermined pressure, and detecting presence or absence of the sheet by an operation of the operating piece; and

a regulating member disposed in the vicinity of an end portion of the paper-sheet-placing table on the upstream side in the paper-feeding direction and regulating movement of the paper sheet on the upstream side in the paper-feeding direction,

the regulating member has a plurality of regulating portions having different heights from the mounting surface of the paper-sheet mounting table,

the plurality of regulating portions are arranged such that the height increases toward an upstream side in the paper feeding direction.

2. The sheet feeding apparatus as set forth in claim 1,

the paper sheet loading table is a manual tray,

a plurality of types of paper sheets having different lengths in the paper feeding direction are selectively placed on the manual feed tray.

3. The sheet supplying apparatus according to claim 1 or 2,

an extended paper sheet placing table for a large paper sheet inclined downward toward the downstream side in the paper feeding direction is connected to an end portion of the paper sheet placing table on the upstream side in the paper feeding direction,

the angle of inclination of the extended paper placing table is set to be larger than the angle of inclination of the paper placing table,

the regulating member is disposed at a position near a connecting portion between the paper-sheet-placing table and the extended paper-sheet-placing table.

4. The sheet supply device according to any one of claims 1 to 3,

the restricting members are disposed on both left and right sides across a center of a width of the sheet in a direction orthogonal to the sheet feeding direction.

5. The sheet supply device according to any one of claims 1 to 4,

in the plurality of regulating portions, the interval between adjacent ones of the regulating portions is set to a length smaller than an amount of movement of the operating piece toward the upstream side in the paper feeding direction.

6. The sheet supply device according to any one of claims 1 to 5,

the plurality of restricting portions are formed in a stepped, comb, or brush shape.

7. An image forming apparatus is characterized by comprising:

the paper supply device of any one of claims 1 to 6;

a drawing section that draws the paper sheet placed on the paper sheet placing table into the inside; and

an image forming section that forms an image on the sheet introduced by the introducing section.

Technical Field

The present invention relates to a paper feeding device for feeding paper to an image forming apparatus and an image forming apparatus including the same, and more particularly to a configuration for accurately detecting the presence or absence of paper placed on a paper placing table.

Background

Conventionally, in patent document 1, a paper feed cassette is provided as a paper feed device, and a rear end regulating plate is disposed so as to be movable in the front-rear direction at a rear end position of the paper feed cassette. In this configuration, after the sheet bundle is stacked in the sheet feed cassette, the rear end regulating plate is moved forward and pressed against the rear end of the sheet bundle, so that the front end portion of the sheet bundle is reliably positioned at the front end portion of the sheet feed cassette.

In patent document 2, a friction member is disposed on an upper surface of a bottom plate constituting a paper feed path in the image forming apparatus, in the middle of the paper feed path through which paper from a manual feed tray is introduced. In this configuration, when two sheets of paper are finally stacked on the bottom plate, the friction force of the friction member on the top surface of the bottom plate suppresses the lower final sheet from being carried together with the upper sheet.

Disclosure of Invention

Technical problem to be solved by the invention

Further, the paper feeding apparatus has the following configuration: the sheet feeding device is provided with a mechanism for detecting the presence or absence of a sheet on a sheet placing table such as a sheet feeding cassette or a manual tray. In this mechanism, the paper-sheet-placing table is disposed so as to be inclined downward toward the downstream side in the paper-feeding direction, and an operation piece is provided for pressing the leading end portion of the paper sheet placed on the paper-sheet-placing table toward the upstream side in the paper-feeding direction at a predetermined pressure. When there is no sheet, the operating piece is moved to an initial position on the upstream side in the sheet feeding direction with a predetermined pressure, and when a large number of sheets are placed, the operating piece is pushed back from the initial position to the rear (the downstream side in the conveying direction) against the predetermined pressure by the weight of the sheets, and the placement of the sheets is detected.

However, when the number of sheets of paper to be placed is small, for example, one sheet or two sheets, the weight of the paper is light, and therefore the operating piece may be moved to the initial position by a predetermined pressure. Therefore, in this case, it is erroneously detected that there is no sheet on the sheet mounting table.

Therefore, it is conceivable to dispose a rear end regulating plate at the rear end of the paper table by the technique of patent document 1. However, in this idea, adjustment such as manually moving the position of the rear end regulating plate in the front-rear direction is required each time a sheet having a different length in the sheet feeding direction is placed on the sheet placing table, which is troublesome. In particular, when the paper sheet placing table is a manual tray, since the frequency of placing paper sheets of various sizes is high, it is troublesome to move the rear end regulating plate every time the paper sheet placing table is placed.

Further, it is also conceivable that the technique of patent document 2 is used to dispose a friction member (friction sheet) on the mounting surface of the paper-sheet mounting table, but since a friction force is generated between the friction member and the lower surface of the final paper sheet, the operation piece is moved easily to the upstream side in the paper feeding direction at a predetermined pressure in a case where the final paper sheet floats up with a slight gap between the friction member and the final paper sheet, and the detection of the paper sheet may not be reliable.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a paper feeding device configured to enable reliable detection of the presence of paper sheets even when the paper sheets are placed on a paper sheet placing table without any manual operation even if the sizes (lengths in the paper feeding direction) of the paper sheets are different from each other, and even when the number of the paper sheets is small.

Means for solving the problems

The paper feeding device according to the present invention is a paper feeding device for feeding paper to an image forming apparatus, comprising: a sheet mounting table having a mounting surface on which a sheet is mounted and which is inclined downward toward a downstream side in a sheet feeding direction in which the sheet is fed to the image forming apparatus; a sheet detecting section having an operating piece for pressing a downstream end of the sheet in a sheet feeding direction toward an upstream side in the sheet feeding direction at a predetermined pressure, and detecting presence or absence of the sheet by an operation of the operating piece; and a regulating member that is disposed in the vicinity of an end portion of the paper-sheet-placing table on the upstream side in the paper-feeding direction and regulates movement of the paper sheet on the upstream side in the paper-feeding direction, wherein the regulating member includes a plurality of regulating portions having different heights from a placing surface of the paper-sheet-placing table, and the plurality of regulating portions are disposed such that the heights increase toward the upstream side in the paper-feeding direction.

In the above configuration, the paper-sheet-placing table is inclined downward toward the downstream side in the paper feeding direction. When a sheet is placed on the sheet placing table, the end portion of the sheet on the upstream side in the sheet feeding direction is placed so as to enter the arrangement range of the plurality of regulating portions of the sheet placing table.

In this state, when a large number of sheets of paper are placed on the paper-placing table, that is, when the pressure on the downstream side in the paper-feeding direction due to the weight of the paper overcomes the predetermined pressure, the operating piece moves to the downstream side in the paper-feeding direction due to the weight of the paper, and therefore the paper-detecting section accurately detects the presence of the paper.

On the other hand, when the number of sheets of paper on the paper table is small, for example, one or two sheets, that is, when the pressure on the downstream side in the paper feeding direction due to the weight of the paper is lower than a predetermined pressure, the operation piece pushes back the tip end portion (the end portion on the downstream side in the paper feeding direction) of the paper toward the upstream side in the paper feeding direction, but when the rear end portion (the end portion on the upstream side in the paper feeding direction) of the paper is locked to an arbitrary regulating portion of the regulating member disposed on the paper table, the movement of the paper is regulated and stopped by the regulating portion. Therefore, the operation piece does not move further to the upstream side in the paper feeding direction, and the paper detecting section accurately detects the presence of the paper on the paper placing table.

Here, the regulating member is constituted by a plurality of regulating portions, and the height of the regulating portions (height from the mounting surface of the paper-sheet mounting table) is arranged to increase toward the upstream side in the paper feeding direction. Therefore, when the lengths of the sheets of paper placed on the paper placing table in the paper feeding direction are different from each other, for example, when there is a tolerance (for example, about 1.5 mm) even in sheets of paper of a regular size such as a postcard, when there is a slight positional deviation between the placed sheets of paper in the paper feeding direction, and further when various types of customized sheets of paper having different lengths in the paper feeding direction are selectively placed, the end portion of the sheet of paper on the upstream side in the paper feeding direction is reliably locked to any one of the plurality of regulating portions. Therefore, even when various kinds of paper sheets having different lengths in the paper feeding direction are selectively placed on the paper placing table, it is not necessary to move and adjust the regulating member in the front-rear direction as in the conventional case every time the paper sheets are placed. Further, since any one of the plurality of regulating portions locks the rear end of the paper, even in a state where the paper slightly floats from the mounting surface of the paper mounting table, the movement of the paper to the upstream side in the paper feeding direction can be reliably regulated and prevented in comparison with a configuration in which a friction member is disposed on the mounting surface as in the related art.

When there is no sheet on the sheet placing table, the operating piece moves to the upstream side in the sheet feeding direction by a predetermined pressure and moves by a desired total movement amount, so that the sheet detecting section accurately detects that there is no sheet on the sheet placing table.

In one embodiment of the present invention, the paper feeding device is characterized in that an extended paper sheet placing table for a large paper sheet is connected to an end portion of the paper sheet placing table on an upstream side in the paper feeding direction, the extended paper sheet placing table being inclined downward toward the downstream side in the paper feeding direction, an angle of inclination of the extended paper sheet placing table is set to be larger than an angle of inclination of the paper sheet placing table, and the regulating member is disposed in a position near a connecting portion between the paper sheet placing table and the extended paper sheet placing table.

In the above-described one embodiment, when the paper-feeding-direction length of the paper is a large paper exceeding the paper-placing table, the large paper is placed on the paper-placing table and the extended paper-placing table. In this case, since the inclination angle of the extended paper-sheet-placing table is larger than the inclination angle of the paper-sheet-placing table, when a large paper sheet is placed so as to straddle the paper-sheet-placing table and the extended paper-sheet-placing table, a void space surrounded by the periphery of the connection portion and the lower surface of the large paper sheet is generated below the large paper sheet placed thereon and around the connection portion between the extended paper-sheet-placing table and the paper-sheet-placing table. Further, since the restriction member is disposed in the void space, the restriction member does not interfere with the feeding operation of the large paper in the paper feeding direction. Therefore, the large paper can be easily and smoothly fed without manual operation such as removal of the regulating member.

In another embodiment of the present invention, in the paper feeding device, the restriction member is configured such that the plurality of restriction portions set a distance between adjacent restriction portions to a length smaller than an amount of movement of the operation piece toward an upstream side in the paper feeding direction.

In the above-described another embodiment, when the sheet placed on the sheet placing table is light in weight, for example, thin paper, the operating piece is intended to move toward the upstream side in the sheet feeding direction against the weight of the sheet by a predetermined pressure. However, since the distance between adjacent restricting portions is set to a length smaller than the amount of movement of the operating piece toward the upstream side in the paper feeding direction, the end portion of the paper on the upstream side in the paper feeding direction is locked to any one of the restricting portions in a stage before the operating piece moves by the desired amount of movement, and further movement of the paper toward the upstream side in the paper feeding direction can be prevented. Therefore, the movement of the operating piece is inhibited at a stage in the middle of the movement of the desired total movement amount, and the paper sheet detecting section can accurately detect the presence of the paper sheet on the paper sheet placing table.

Effects of the invention

According to the present invention, in the paper feeding device and the image forming apparatus including the paper feeding device, only by selectively placing various kinds of paper sheets having different lengths in the paper feeding direction on the paper sheet placing table, there is no need for any manual operation such as changing or adjusting the position of the regulating member on the paper sheet placing table or removing the regulating member, and even if the paper sheet placed on the paper sheet placing table slightly floats up due to a gap between the paper sheet placing table and the paper sheet placing surface, the presence of the paper sheet on the paper sheet placing table can be reliably and accurately detected.

Drawings

Fig. 1 is a cross-sectional view showing an image forming apparatus including a paper feeding device according to a first embodiment.

Fig. 2 is a side view schematically showing the periphery of a manual paper feeder.

Fig. 3 is a plan view schematically showing the periphery of the hand-operated apparatus.

Fig. 4 is a side sectional view showing a specific configuration of the hand-operated device in an enlarged manner.

Fig. 5 is an enlarged side sectional view of the periphery of a paper presence/absence sensing actuator provided in the manual operation device.

Fig. 6 is an enlarged side sectional view of the periphery of a regulating member provided in the manual operation device.

Fig. 7 is a side sectional view showing the periphery of a regulating member provided in the manual operation device according to the second embodiment.

Fig. 8 is a side sectional view showing the periphery of a regulating member provided in a manual operation device according to a third embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(first embodiment)

Fig. 1 is a cross-sectional view showing an image forming apparatus including a paper feeding device according to a first embodiment.

In the figure, the image forming apparatus 1 has a copy function of reading a document and printing on a recording sheet, and includes: an original reading device 2, an original conveying device (ADF)3, a printing portion 4, a paper feeding device 5, a manual device (paper feeding device) 7, a paper conveying portion 8, and the like. The document reading device 2 and the document feeding device 3 are mounted on the upper side of the main body of the image forming apparatus 1, the printing unit 4, the sheet feeding device 5, and the sheet feeding unit 8 are built in the main body of the image forming apparatus 1, and the manual device 7 is attached to a side wall of the main body of the image forming apparatus 1.

The image data handled in the image forming apparatus 1 corresponds to a color image using each of black (K), cyan (C), magenta (M), and yellow (Y), or corresponds to a monochrome image using a single color (for example, black). Therefore, in the printing section (image forming section) 4, four developing devices 12, four photosensitive drums 13, four drum cleaning devices 14, four charging devices 15, and the like are provided for forming four toner images corresponding to the respective colors, and the four image stations Pa, Pb, Pc, and Pd are configured in association with black, cyan, magenta, and yellow, respectively.

After residual toner on the surface of the photosensitive drum 13 is removed and collected by the drum cleaning device 14 for each of the image stations Pa, Pb, Pc, and Pd, the surface of the photosensitive drum 13 is uniformly charged at a predetermined potential by the charging device 15, the surface of the photosensitive drum 13 is exposed by the optical scanning device 11, an electrostatic latent image is formed on the surface thereof, and the electrostatic latent image on the surface of the photosensitive drum 13 is developed by the developing device 12, thereby forming a toner image on the surface of the photosensitive drum 13. Thereby, toner images of the respective colors are formed on the surfaces of the photosensitive drums 13.

Thereafter, the intermediate transfer belt 21 is moved around in the arrow direction C, and the residual toner on the intermediate transfer belt 21 is removed and collected by the belt cleaning device 22, and the toner images of the respective colors formed on the surfaces of the photosensitive drums 13 are transferred to the intermediate transfer belt 21, thereby forming a color toner image on the intermediate transfer belt 21.

A nip region is formed between the intermediate transfer belt 21 and the transfer roller 23a of the secondary transfer device 23, and the recording paper conveyed through the S-shaped paper conveyance path R1 is nipped and conveyed to the nip region, and the color toner image on the surface of the intermediate transfer belt 21 is transferred onto the recording paper. Then, the recording paper is sandwiched between the heating roller 24 and the pressure roller 25 of the fixing device 17, and is heated and pressed, thereby fixing the color toner image on the recording paper.

On the other hand, in the paper transport section (pull-in section) 8, the recording paper is fed out from the paper feed device 5 and the manual operation device 7, transported through the paper transport path R1, and pulled in, and the recording paper is moved out to the paper discharge tray 39 by the paper discharge rollers 36 via the secondary transfer device 23 and the fixing device 17. In the paper transport path R1, there are disposed: registration rollers 34, which temporarily stop the recording paper and start the conveyance of the recording paper in accordance with the transfer timing of the toner image at the nip region between the intermediate transfer belt 21 and the transfer roller 23a after the leading end of the recording paper is aligned, conveyance rollers 35, which urge the conveyance of the recording paper, discharge rollers 36, and the like.

The paper feeding device 5 includes: a cassette 51 disposed at a lower portion of the image forming apparatus 1, a paper feed tray 52 on which recording paper is stacked, a pickup roller 53 provided above one end of the paper feed tray 52, a paper feed roller 54 disposed downstream of the pickup roller 53 in a paper conveyance direction (hereinafter, referred to as a paper feed direction), a separation roller 55 pressed against the paper feed roller 54, and the like. In the paper feeding device 5, the recording paper is pulled out from the paper feeding tray 52 by the pickup roller 53 and guided to the paper feeding roller 54, and the recording paper is separated one by passing between the paper feeding roller 54 and the separation roller 55 and sent out to the paper conveying path R1.

The manual operation device 7 is disposed on a side wall of the main body of the image forming apparatus 1, and includes: a manual tray (paper table) 71 on which recording paper (paper) is stacked, a paper feed roller 72 provided above one end of the manual tray 71, a separation roller 73 in pressure contact with the paper feed roller 72, and a paper guide member 74 disposed upstream of a nip region between the paper feed roller 72 and the separation roller 73 in the paper feed direction of the recording paper. In the manual paper feeding device 7, the recording paper is guided from the manual paper tray 71 to the nip area between the paper feeding roller 72 and the separation roller 73 via the paper guide member 74 by the rotation of the paper feeding roller 72 in the clockwise direction F in the figure, and the recording paper is separated one by the nip area and sent out to the paper feeding path R1.

Next, the manual operating device 7 of the first embodiment of the paper feeding device of the present invention will be described in detail. Fig. 2 is a side view schematically showing the manual device 7.

As shown in fig. 2, the manual feed tray 71 is disposed with its leading end portion 71a inclined downward, and at its leading end portion 71a, a first inclined contact portion 71b, a second inclined contact portion 71c, and a third inclined contact portion 71d are provided in this order from the upstream side in the paper feeding direction E of the recording paper. A pair of guide plates 75 for sandwiching and guiding the recording paper are provided on the upper surface of the manual feed tray 71. The guide plates 75 are movable in a direction orthogonal to the paper feed direction E, and are moved symmetrically and interlockingly with respect to the center of the manual feed tray 71 by a mechanism not shown, so that the center of the recording paper sandwiched between the guide plates 75 coincides with the center of the manual feed tray 71.

A paper feed roller 72 is disposed above the third inclined contact portion 71d of the distal end portion 71a of the manual tray 71, and a separation roller 73 is disposed below the paper feed roller 72. The shaft 73a of the separation roller 73 is parallel to the drive shaft 72a of the feed roller 72, and a bearing (not shown) of the shaft 73a of the separation roller 73 is biased toward the feed roller 72 by a spring (not shown), and the separation roller 73 is pressed against the feed roller 72, so that a nip region H is formed between the feed roller 72 and the separation roller 73.

The third inclined contact portion 71d has a paper guide member 74 fixed to its upper end portion, the paper guide member 74 extends toward the surface of the paper feed roller 72, and the tip end of the paper guide member 74 contacts with or is slightly separated from the surface of the paper feed roller 72.

Fig. 3 is a plan view schematically showing the periphery of the hand device 7. Fig. 4 is a side view showing a specific configuration of the hand-operated device 7 in an enlarged manner. As shown in fig. 3, in the manual feed device 7, the manual feed tray 71 is formed in a rectangular shape elongated in a direction (hereinafter, also referred to as a lateral width direction) orthogonal to the paper feed direction E. The length of the manual tray 71 on the paper feed direction E side is set near the length of a small-sized recording sheet, for example, a 6-sized recording sheet. The upper surface of the manual feed tray 71 is formed into a substantially flat surface, and this flat surface is a placement surface 71g on which recording paper is placed. As shown in fig. 4, when the small-sized recording paper Ps is placed on the placement surface 71g, an end portion (hereinafter, also referred to as a rear end portion) of the recording paper Ps on the upstream side in the paper feeding direction E is positioned at the rear end portion of the manual feed tray 71. The pair of guide plates 75 are provided on the mounting surface 71g, and the center of the recording paper is positioned on the mounting surface 71g on the center line l in the lateral width direction by the guide plates 75.

An extension tray (extension paper table) 80 formed in a rectangular shape is disposed on the upstream side of the manual tray 71 in the paper feeding direction E. The extension tray 80 has two connecting portions 80a and 80b protruding in the paper feeding direction E at an end portion (hereinafter, also referred to as a tip end portion) on the downstream side in the paper feeding direction E. The two coupling portions 80a and 80b are formed at the left and right end portions (one end portion and the other end portion in the direction orthogonal to the paper feeding direction E) of the extension tray 80, and are pivotally supported by a pivot support point (not shown) formed at the rear end portion of the manual feed tray 71 so as to be rotatable. As shown in fig. 4, the two connection portions 80a and 80b are formed with projecting portions 80c and 80d projecting upward. The top surface of the extension tray 80 is formed into a flat surface except the projections 80c and 80d, and this flat surface serves as a placement surface 80e on which the rear portion of the large recording paper is placed.

In fig. 3, the paper feed roller 72 is disposed near the downstream end of the manual feed tray 71 in the paper feed direction E. The center of the feed roller 72 is located on an extension of the center line l of the manual feed tray 71.

Fig. 4 shows a state in which the manual tray 71 and the extension tray 80 are opened. Although not shown in detail, the lower end portion of the manual tray 71 is pivotally supported on a side wall 1a forming a side wall of the main body of the image forming apparatus 1 so as to be rotatable, and is positioned at a closed position where the manual tray 71 is accommodated in the side wall 1a of the image forming apparatus 1 and an open position shown in the figure where the manual tray 71 is rotated clockwise in fig. 4 from the closed position around a pivot supporting point.

On the other hand, the extension tray 80 is positioned at a storage position located immediately above the manual tray 71 and an extended position shown in the figure in which the extension tray 80 is rotated clockwise in fig. 4 about the pivot point and a continuous placement surface is formed by the manual tray 71 and the extension tray 80.

When the recording paper is fed by the manual operation device 7, the manual tray 71 is positioned at the open position shown in the figure, and the extension tray 80 is positioned at the extension position from the storage position. In this state, the small-sized recording paper Ps is placed on the placement surface 71g of the manual feed tray 71. On the other hand, when the rear end of the sheet to be placed exceeds the large-size recording sheet Pl at the rear end of the manual tray 71, the front part of the large-size recording sheet Pl is placed on the placement surface 71g of the manual tray 71, and the rear part thereof is placed on the placement surface 80e of the extension tray 80. At this time, the rear portion of the large-size recording paper Pl is placed on the placement surface 80e in a state where it abuts against and is lifted upward by the protruding portions 80c and 80d formed by the two connecting portions 80a and 8b of the extension tray 80.

As is apparent from fig. 4, when the manual feed tray 71 is in the open position shown in the drawing, the rear end portion thereof is positioned above the pivot point (not shown) at the distal end portion, and the entire manual feed tray 71 is positioned so as to be inclined at the inclination angle θ 1 toward the downstream side in the paper feed direction E. Therefore, when the small-sized recording paper Ps is placed on the placement surface 71g of the manual feed tray 71, the recording paper Ps moves toward the downstream side in the paper feed direction E due to its own weight.

When the extension tray 80 is also in the illustrated extension position, the rear end portion thereof is positioned above a pivot support point (not illustrated) at the distal end portion, and the entire extension tray 80 is positioned so as to be inclined at an inclination angle θ 2 toward the downstream side in the paper feeding direction E. The inclination angle θ 2 of the extension tray 80 is different from the inclination angle θ 1 of the manual tray 71, and is set to be larger than the inclination angle θ 1 of the manual tray 71 (θ 2> θ 1).

As shown in fig. 4, a paper detection unit 90 is disposed in the vicinity of the tip end of the manual feed tray 71 so as to face the tip end. The paper detection unit 90 is disposed on the side of the paper feed roller 72 (in a direction orthogonal to the paper feed direction E) as shown in fig. 3, and includes a paper presence/absence sensing actuator (operating piece) 91.

As shown in enlarged detail in fig. 5, the paper presence/absence sensing actuator 91 is composed of a plate 91a shaped like a letter "く" bent like a letter "く" (japanese), a linking plate 91b shaped like a square, and an urging spring 91 c. The plate 91a shaped like the letter "く" is composed of a horizontal plate 91d arranged substantially parallel to the paper feeding direction E, and a rising plate 91E rising upward from the upstream end of the horizontal plate 91d in the paper feeding direction E, and the leading end portions of the recording sheets Ps and Pl on the manual feed tray 71 abut on the vicinity of the lower end portion of the rising plate 91E due to their own weight or the like. The downstream end of the horizontal plate 91d of the "く" shaped plate 91a in the paper feeding direction E is fixed to a shaft 92, and the shaft 92 is provided on the image forming apparatus 1 main body. The lower end of the connecting plate 91b is also connected to the shaft 92, and an opening 91f that opens downstream in the paper feed direction E is formed at the upper end of the connecting plate 91 b. The biasing spring 91c is compressed between the opening 91f and the main body of the image forming apparatus 1.

In the paper presence/absence sensing actuator 91, the coupling plate 91b is rotated about the shaft 92 toward the upstream side in the paper feeding direction E by the biasing force (predetermined pressure) of the biasing spring 91c, and the "く" -shaped plate 91a is rotated toward the upstream side in the paper feeding direction E in association with the rotation of the shaft 92 in the clockwise direction, so that the tip end portions of the recording papers Ps and Pl on the manual feed tray 71 are pushed back toward the upstream side in the paper feeding direction E.

When the sheets Ps and Pl are not recorded on the placement surface 71g of the manual feed tray 71, the "く" shaped plate 91a of the sheet presence/absence sensing actuator 91 is positioned at the initial position where it is completely rotated toward the upstream side in the sheet feeding direction E by the biasing force of the biasing spring 91 c. On the other hand, when there are many small-sized recording sheets Ps on the placement surface 71g of the manual feed tray 71 or when there are large-sized recording sheets Pl, the "く" -shaped plate 91a is pushed downstream in the paper feed direction E by the weight of the recording sheets Ps, and is rotated downstream in the paper feed direction E while contracting the biasing spring 91c, thereby being displaced from the initial position. The paper detection unit 90 includes a position sensor (not shown) for detecting the position of the く -shaped plate 91a of the paper presence/absence sensing actuator 91, and detects the absence of the recording paper Ps or Pl on the mounting surface 71g of the manual feed tray 71 when the く -shaped plate 91a is at the initial position, and detects the presence of the recording paper Ps or Pl when the manual feed tray is out of the initial position.

In the paper presence/absence sensing actuator 91, the amount of movement of the "く" shaped plate 91a, that is, the amount of movement from the initial position to the pressed position after the "く" shaped plate 91a has been rotated, in a state in which the biasing spring 91c has been fully contracted by the pressing in the downstream side of the paper feed direction E due to the weight of the recording paper Ps, Pl, is set to, for example, about 1.5mm which is 2mm or less.

As shown in fig. 3, two regulating members 100 for regulating the movement of the small-size recording paper Ps placed on the placement surface 71g toward the upstream side in the paper feeding direction E are disposed near the rear end of the manual tray 71, that is, near the connection portion between the manual tray 71 and the extension tray 80. The restricting member 100 is located in a space sandwiched between the two coupling portions 80a and 80b of the extension tray 80 in a direction orthogonal to the paper feeding direction E. One of the two restricting members 100 is disposed in the left-right direction (the direction orthogonal to the paper feeding direction E) with the center line l of the manual feed tray 71 interposed therebetween. Therefore, the two regulating members 100 are positioned at bilaterally symmetrical positions with respect to the paper feed roller 72 on the center line l. Further, the two regulating members 100 are arranged so as to be positioned within the lateral width of the recording paper Ps when the recording paper Ps having the smallest lateral width is positioned on the center line l by the pair of guide plates 75. One of the restricting members 100 is located on a line extending the position where the paper presence/absence sensing actuator 91 is disposed toward the upstream side in the paper feeding direction E.

The two restricting members 100 have the same structure as each other. Fig. 6 shows an enlarged side sectional view of the periphery of the restricting member 100.

In fig. 6, the plurality of blades of the regulating member 100 are formed in a zigzag shape continuously arranged on a straight line on the side of the paper feeding direction E. Each of the plurality of blades constitutes a regulating portion 101 for regulating the movement of the rear end portion of each of the recording sheets Ps having different lengths in the paper feeding direction E to the upstream side in the paper feeding direction E. Each restriction portion 101 has: a steep surface 101a that steeply rises in a substantially vertical direction with the manual feed tray 71 tilted at a tilt angle θ 1, and a rear slope 101b that descends obliquely downward and rearward from a vertex of the steep surface 101 a. The steep elevation 101a has the following functions: when the recording paper Ps moves to the upstream side in the paper feed direction E while facing the rear end of the recording paper Ps on the manual feed tray 71, the rear end surface of the recording paper Ps abuts against the steep surface 101a, and the movement to the upstream side in the paper feed direction E is restricted and prevented.

The plurality of regulating portions 101 are arranged such that the height h from the placement surface 71g of the manual feed tray 71, that is, the length from the placement surface 71g to the apex of the steep surface 101a, is different from each other, and the height h is higher as the regulating portion 101 is located on the upstream side in the paper feeding direction E.

In the plurality of regulating portions 101, the distance S between two adjacent regulating portions 101, that is, the distance between the apexes of the steep surfaces 101a is set to be shorter than the length of the movement from the initial position to the pressed position of the く -shaped plate 91a of the paper presence/absence sensing actuator 91. For example, when the amount of movement of the "く" shaped plate 91a of the paper presence/absence sensing actuator 91 is set to 2mm, the length of less than 2mm is set to 1.2mm, for example. In addition, the distance S does not need to be set to the same length (equal pitch) between the two adjacent regulating portions 101, and in short, may be set to a length smaller than the moving amount of the "く" character plate 91 a.

Between the two adjacent regulating portions 101, the difference d in height h between the apexes of the steep surfaces 101a is set to be approximately two sheets of recording paper Ps placed on the manual feed tray 71.

In the regulating member 100, the length of the regulating portion 101 on the side of the paper feeding direction E, that is, the length of the whole regulating portion is set to about 15mm in the present embodiment, for example.

In fig. 6, the case where 15 restricting units 101 are arranged is illustrated, but the number of the arrangement can be set as appropriate.

As described above, in the present embodiment, when the small-sized recording paper Ps is supplied to the inside of the image forming apparatus 1 by the manual paper feeder 7, the manual tray 71 is positioned at the open position, the extension tray 80 is positioned at the extended position, and the recording paper Ps is placed on the placement surface 71g of the manual tray 71 in this state.

In this state, when the recording paper Ps is a large number of sheets, the manual feed tray 71 is inclined toward the downstream side at the inclination angle θ 1, and therefore the recording paper Ps moves toward the downstream side in the paper feed direction E due to its own weight. Therefore, in the paper presence/absence sensing actuator 91, the "く" shaped plate 91a is pushed by the weight of the recording paper Ps in the downstream side in the paper feeding direction E, and is rotated in the downstream side in the paper feeding direction E against the biasing force of the biasing spring 91c, and is moved away from the home position. Therefore, the paper detection section 90 detects that the recording paper Ps is present on the manual feed tray 71. In this state, the rear end portion of the recording paper Ps is located within the range of arrangement of the plurality of regulating portions 101 of the regulating member 100 at the rear end portion of the manual feed tray 71.

On the other hand, when the number of the recording sheets Ps on the manual feed tray 71 is, for example, one or two and the pressing force to the downstream side in the paper feed direction E by the self weight of the recording sheets Ps is smaller than the urging force of the urging spring 91c of the paper presence/absence sensing actuator 91, the plate 91a shaped like the letter "く" of the paper presence/absence sensing actuator 91 is rotated toward the initial position to the upstream side in the paper feed direction E, and the recording sheets Ps are pushed back to the upstream side in the paper feed direction E. However, when the rear end portion of the recording paper Ps abuts against the steep surface 101a of any one of the plurality of regulating portions 101, the movement of the recording paper Ps further upstream in the paper feeding direction E is regulated and prevented by the regulating portion 101, and the paper presence/absence sensing actuator 91 does not move to the initial position. Therefore, the paper detection section 90 reliably and accurately detects that the recording paper Ps is present on the manual feed tray 71.

Here, the regulating member 100 is constituted by a plurality of regulating portions 101, and the height h of the regulating portions 101 from the placement surface 71g of the manual feed tray 71 is arranged to be higher toward the upstream side in the paper feeding direction E. Therefore, even if a plurality of types of recording paper Ps having different lengths in the paper feeding direction E are selectively placed on the placement surface 71g of the manual feed tray 71, the rear end portions of the recording paper Ps placed thereon reliably abut against and are locked in the vicinity of the apex of the steep surface 101a of the nearest regulating portion 101 (the portion different from the height h of one immediately preceding regulating portion 101) that is first located from the rear end portion of the recording paper Ps to the upstream side in the paper feeding direction E among the plurality of regulating portions 101, and therefore, it is not necessary to move and adjust the regulating member 100 to the upstream side or the downstream side in the paper feeding direction E every time the recording paper Ps is placed.

Therefore, even when there is a tolerance (for example, about 1.5 mm) in the recording paper Ps placed on the manual feed tray 71 even if the recording paper Ps is a paper having a regular size such as a postcard, when there is a slight positional deviation between the plurality of recording paper Ps placed on the paper feed direction E side, and further when various customized papers having different lengths in the paper feed direction E are selectively placed, it is possible to accurately detect that the recording paper Ps is present on the placement surface 71g even if one or two of the recording paper Ps are present.

Further, since the steep surface 101a of any of the plurality of regulating portions 101 abuts against the rear end surface of the recording paper Ps to prevent the recording paper Ps from moving upstream in the paper feeding direction E, even in a state where the recording paper Ps slightly floats from the mounting surface 71g of the manual feed tray 71, the recording paper Ps can be reliably prevented from moving upstream in the paper feeding direction E as compared with a conventional configuration in which a friction member is disposed on the mounting surface and the movement is suppressed by a frictional force with the lower surface of the paper.

When the recording paper sheet Ps is not present on the manual feed tray 71, the "く" shaped plate 91a of the paper presence/absence sensing actuator 91 is positioned at the initial position by the biasing force of the biasing spring 91c, and therefore the paper detection unit 90 accurately detects that the recording paper sheet Ps is not present on the manual feed tray 71.

In the present embodiment, the regulating member 100 is disposed at the rear end portion of the manual feed tray 71, that is, around the connecting portion between the manual feed tray 71 and the extension tray 80, and is set such that the inclination angle θ 2 of the extension tray 80 is larger than the inclination angle θ 1 of the manual feed tray 71 (θ 2> θ 1). Therefore, when a large-sized recording paper sheet Pl is placed so as to straddle the placement surface 71g of the manual feed tray 71 and the placement surface 80e of the extension tray 80, as can be seen from fig. 4, a void space P surrounded by the recording paper sheet Pl and the periphery of the connection portion between the manual feed tray 71 and the extension tray 80 is generated below the recording paper sheet Pl, and the regulating member 100 is positioned in the void space P. Therefore, the regulating member 100 does not interfere with the movement of the recording paper Pl in the paper feeding direction E during the paper feeding of the large-size recording paper Pl. Therefore, the large-size recording paper Pl can be simply fed without a manual operation of removing the regulating member 100 and the like.

In addition, when the large-size recording paper Pl is placed, since the self weight thereof is heavier than the small-size recording paper Ps, even if one or two recording papers Pl are placed, the "く" shaped plate 91a of the paper presence/absence sensing actuator 91 is rotated toward the downstream side in the paper feeding direction E against the biasing force of the biasing spring 91c by the self weight thereof, and is thus displaced from the initial position. Therefore, even if there are one or two large-sized recording sheets Pl, the sheet detecting section 90 accurately detects the placement.

In the present embodiment, the distance between adjacent ones of the plurality of regulating portions 101 of the regulating member 100 is set to a length (e.g., 1.2mm) smaller than the operation amount of the paper presence/absence sensing actuator 91, i.e., the movement amount (e.g., 2mm) from the pressing position of the "く" character plate 91a to the initial position. Therefore, even if the "く" shaped plate 91a of the paper presence/absence sensing actuator 91 pushes back the recording paper Ps toward the upstream side in the paper feeding direction E by the biasing spring 91c, the rear end portion of the recording paper Ps is locked by any one of the steep surfaces 101a of the plurality of regulating portions 101 at a stage in which the "く" shaped plate 91a reaches the initial position, and further movement toward the upstream side in the paper feeding direction E is prevented. Therefore, the "く" shaped plate 91a of the paper presence/absence sensing actuator 91 does not reach the initial position, and the paper detection unit 90 accurately detects that the recording paper Ps is present on the manual feed tray 71.

In the present embodiment, the two regulating members 100 are disposed on both the left and right sides across the center line l within the lateral width of the small-sized recording paper Ps placed on the manual feed tray 71. Therefore, even if the paper presence/absence sensing actuator 91 pushes back the leading end portion of the recording paper Ps at a position offset from the center line l, the recording paper Ps is positioned at a position bilaterally symmetrical with respect to the center line l by the two regulating members 100, and the occurrence of positional offset in the left or right direction is suppressed.

(second embodiment)

Fig. 7 shows a main part of a paper feeding device according to a second embodiment.

In the foregoing first embodiment, the restricting member 100 is formed in a zigzag shape, but in the present embodiment, it is formed in a comb shape.

That is, in the restricting member 100 shown in fig. 7, a plurality of guide bars extending in a row toward the upstream side in the paper feeding direction E are provided at the rear end portion of the manual feed tray 71, and the guide bars are provided as a plurality of restricting portions 101. The plurality of regulating portions 101 are each formed in a rectangular shape extending upward from the mounting surface 71g, and are arranged such that the height from the mounting surface 71g increases toward the upstream side in the paper feeding direction E, as in the first embodiment.

(third embodiment)

Fig. 8 shows a main part of a paper feeding device according to a third embodiment.

In the present embodiment, the restricting member 100 is formed in a brush shape. That is, in fig. 8, a plurality of linear bristles extending upward from the mounting surface 71g are arranged on the paper feeding direction E side and in the lateral width direction, the plurality of bristles are formed into a plurality of regulating portions 101, and the plurality of regulating portions 101 are arranged such that the height from the mounting surface 71g increases toward the upstream side in the paper feeding direction E.

In the present embodiment, since the plurality of regulating portions 101 are arranged toward the upstream side in the paper feeding direction E, the amount of push-back of the recording paper Ps placed on the manual feed tray 71 toward the upstream side in the paper feeding direction E can be minimized.

In the above description, the restricting member 100 has a zigzag shape, a comb shape, or a brush shape, but may have a plurality of rib shapes that are continuous and stepped. Further, the above shape may be made higher toward the upstream side in the paper feeding direction E by using sponge, high friction sheet MAGIC TAPE (registered trademark).

In the above embodiment, the present invention is applied to the manual operating device 7, but it is needless to say that the present invention can also be applied to the document reading device 2 and the document feeding device 3, and the presence/absence of document sheets placed thereon can be accurately detected.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. Therefore, the above embodiments are merely examples and are not to be construed as limiting. All changes and modifications that fall within the scope of the claims of the present invention are also encompassed within the scope of the present invention.

Industrial applicability

In the present invention, the paper feeding device does not require any manual operation such as changing or adjusting the position of the regulating member disposed on the paper sheet placing table or removing the regulating member, and can reliably and accurately detect the presence of the paper sheet on the paper sheet placing table even if there are one or two or so paper sheets on the paper sheet placing table.

Description of the reference numerals

1: image forming apparatus with a toner supply device

4: printing part (image forming part)

7: hand operated device (paper feeding device)

71: manual tray (paper placing table)

71 g: carrying surface

E: paper feed direction

72: paper feeding roller

8: paper conveying part (lead-in part)

80: extension tray (extension paper placing table)

80 a: connecting part

80 e: carrying surface

90: paper sheet detection unit

91: paper presence/absence detection actuator (action piece)

91 a: 'く' shaped board

91 c: force application spring

Ps: small-sized recording paper (paper)

Pl: large-sized recording paper (paper)

100: restraining member

101: restricting part

101 a: steep vertical surfaces.