JP2020007061A - Paper feeder, and image forming apparatus provided with the same - Google Patents

Abstract

To correctly detect that a paper sheet is present on a paper placement tray without requiring any manual operation, even when size of the paper sheet to be placed variously differs therefrom, according to a paper feeder.SOLUTION: According to a paper feeder 7 for feeding a paper sheet to an image forming apparatus 1, a paper placement tray 71 for placing a paper sheet Ps on a placement face 71g is inclined downward toward a downstream side in a paper feeding direction E. A paper detection part 90 comprises an operation piece 91 for pushing a tip of the paper sheet Ps onto an upstream side in the paper feeding direction E by a predetermined pressure. A regulation member 100 is arranged near an end portion on the upstream side in the paper feeding direction E of the paper placement tray 71. The regulation member 100 for regulating movement of the paper sheet Ps onto the upstream side in the paper feeding direction E comprises a plurality of regulation parts 101 each having different height from the placement face 71g of the paper placement tray 71. The plurality of regulation parts 101 are arranged so that the height becomes high toward the upstream side in the paper feeding direction E.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet feeder that supplies sheets to an image forming apparatus and an image forming apparatus including the same, and more particularly, to a structure for accurately detecting the presence or absence of a sheet placed on a sheet placing table.

  Conventionally, in Patent Document 1, a paper feed cassette is provided as a paper feed device, and a rear end regulating plate is disposed at a rear end position of the paper feed cassette so as to be movable in the front-rear direction. In this configuration, after the stack of sheets is stacked on the sheet cassette, the rear end regulating plate is moved forward, pressed against the rear end of the sheet stack, and brought into contact with the sheet stack, thereby feeding the leading end of the sheet stack. Positioned securely at the end of the paper cassette.

  Further, in Patent Document 2, a friction member is arranged on the upper surface of a bottom plate constituting the paper feeding path in the middle of the paper feeding path for taking the paper from the manual feed tray into the image forming apparatus. In this configuration, when the number of sheets on the bottom plate becomes the last two, the feeding of the lower last sheet together with the upper sheet is suppressed by the frictional force of the friction member on the upper surface of the bottom plate.

JP-A-8-53232 JP 2010-70281 A

  By the way, some paper feeders are provided with a mechanism for detecting the presence or absence of paper on a paper mounting table such as a paper feed cassette or a manual feed tray. In this mechanism, the paper mounting table is disposed so as to be inclined downward toward the downstream side in the paper feeding direction, and the leading end of the paper mounted on the paper mounting table is pressed at a predetermined pressure to the upstream side in the paper feeding direction. An operation piece is provided. When there is no paper, the operating piece is at the initial position where it has moved to the upstream side in the paper feeding direction at a predetermined pressure. On the other hand, when a large number of papers are placed, the operating piece resists the predetermined pressure due to its own weight. Then, the sheet is pushed back from the initial position to the rear (downstream side in the transport direction), thereby detecting that the sheet is loaded.

  However, when the number of sheets placed is small, for example, one or two, the operating piece may move to the initial position due to a predetermined pressure because its own weight is light. Therefore, in this case, it is erroneously detected that there is no sheet on the sheet mounting table.

  Therefore, it is conceivable to arrange a rear end regulating plate at the rear end of the sheet mounting table using the technique of Patent Document 1. However, according to this idea, every time a sheet having a different length in the sheet feeding direction is placed on the sheet placing table, adjustment such as manually moving the position of the rear end regulating plate in the front-rear direction is required, which is troublesome. In particular, when the sheet mounting table is a manual tray, sheets of various sizes are frequently placed, and it is troublesome to move the rear end regulating plate each time the sheet is placed.

  In addition, there is a method of arranging a friction member (friction sheet) on the mounting surface of the sheet mounting table using the technology of Patent Document 2, but the friction member generates a frictional force with the lower surface of the final sheet. Therefore, when the final sheet and the friction member are slightly separated from each other and are floating, the operation piece easily moves to the upstream side in the sheet feeding direction at a predetermined pressure, and sheet detection is not reliable. Concerns remain.

  SUMMARY OF THE INVENTION In view of the above, the present invention has an object to provide a paper feeding device in which only the paper is placed on a paper mounting table, and the size of the paper (length in the paper feeding direction) is variously changed. It is another object of the present invention to provide a configuration that can reliably detect the presence of a sheet without any manual operation and even when the number of sheets is small.

  A paper feeding device according to the present invention is a paper feeding device for supplying paper to an image forming apparatus, wherein paper is placed on a mounting surface, and a downstream side in a paper feeding direction for supplying the paper to the image forming device. A sheet loading table that is inclined downward toward the paper feeder, and an operation piece that presses the downstream end of the paper in the paper supply direction upstream at a predetermined pressure in the paper supply direction, and detects the presence or absence of the paper by the operation of the operation piece. A sheet detecting unit, and a regulating member that is disposed near an end of the sheet placing table on the upstream side in the sheet feeding direction, and regulates movement of the sheet to the upstream side in the sheet feeding direction. The member has a plurality of restricting portions having different heights from the mounting surface of the sheet mounting table, and the plurality of restricting portions are configured such that the height increases toward the upstream side in the sheet feeding direction. It is characterized by being arranged.

  In the above configuration, the sheet mounting table is inclined downward toward the downstream side in the sheet feeding direction. Then, when the sheet is placed on the sheet placing table, the sheet is placed such that the end of the sheet on the upstream side in the sheet feeding direction is within the arrangement range of the plurality of regulating portions of the sheet placing table.

  In this state, when a large number of sheets are placed on the sheet placing table, that is, when the pressure of the sheets due to their own weight on the downstream side in the sheet feeding direction exceeds the predetermined pressure, the operation is performed. Since the piece moves to the downstream side in the paper feeding direction due to the weight of the paper, the paper detection unit correctly detects the presence of the paper.

  On the other hand, when the number of sheets on the sheet mounting table is small, for example, one or two, that is, when the pressure of the sheets due to their own weight on the downstream side in the sheet feeding direction is smaller than a predetermined pressure, the operation piece is the sheet. Although the leading end (the end on the downstream side in the sheet feeding direction) is pushed back to the upstream side in the sheet feeding direction, the rear end (the end on the upstream side in the sheet feeding direction) of the sheet is any one of the regulating members arranged on the sheet table. When the sheet is locked to such a restricting section, the restricting section restricts and prevents the movement of the sheet. Therefore, since the operation piece does not move further upstream in the paper feeding direction, the paper detection unit correctly detects that there is paper on the paper mounting table.

  Here, the regulating member is composed of a plurality of regulating portions, and is arranged such that the height of the regulating portions (the height from the mounting surface of the sheet mounting table) increases toward the upstream side in the paper feeding direction. . Therefore, when the length of the paper placed on the paper mounting table in the feeding direction is variously different, for example, there is a tolerance (for example, about 1.5 mm) even for a fixed size paper such as a postcard, In some cases, there is a slight misalignment in the paper feeding direction between a plurality of papers, and various customized papers having different lengths in the paper feeding direction are selectively placed. However, the ends of the sheets on the upstream side in the sheet feeding direction are securely locked to any of the plurality of regulating portions. Therefore, even when various sheets having different lengths in the sheet feeding direction are selectively placed on the sheet placement table, it is necessary to adjust the regulating member by moving the regulating member in the front-rear direction as in the related art for each placement. There is no. In addition, since any one of the plurality of regulating portions locks the trailing end of the sheet, even if the sheet slightly floats from the placing surface of the sheet placing table, the sheet has a friction as in the related art. Compared to the configuration in which the members are arranged, it is possible to reliably restrict and prevent the sheet from moving upstream in the sheet feeding direction.

  When there is no paper on the paper loading table, the operating piece moves to the upstream side in the paper feeding direction by a predetermined pressure, and moves all of the intended movement amount. If not, it is detected correctly.

  In one embodiment of the present invention, an extended paper loading table for large paper that is inclined downward toward the downstream in the paper feeding direction is connected to an end of the paper loading table on the upstream side in the paper feeding direction. The angle of the inclination of the mounting table is set to be larger than the angle of the inclination of the paper mounting table, and the regulating member is disposed at a position near a connection portion between the paper mounting table and the extended paper mounting table. It is characterized by having been done.

  In the above embodiment, in the case of a large sheet whose length in the sheet feeding direction exceeds the sheet table, the large sheet is placed using the sheet table and the extended sheet table. At that time, since the inclination angle of the extended paper placing table is larger than the inclination angle of the paper placing table, when a large sheet is placed over the sheet placing table and the extended sheet placing table, the large sheet is placed. Below the large sheet, an empty space is created around the connection between the extended sheet table and the sheet table and surrounded by the connection and the lower surface of the large sheet. Since the regulating member is arranged in the empty space, the regulating member does not interfere with the operation of feeding the large sheet in the sheet feeding direction. Therefore, large paper can be easily and smoothly fed without requiring manual operation such as removal of the regulating member.

  In another embodiment of the present invention, in the restricting member, the plurality of restricting portions have a distance between adjacent restricting portions, the length of which is smaller than the amount of operation of the operation piece toward the upstream side in the sheet feeding direction. It is characterized by being set.

  In the other embodiment, when the paper placed on the paper placing table is, for example, thin paper, and the weight of the paper is light, the operating piece overcomes the weight of the paper by a predetermined pressure and moves toward the upstream side in the paper feeding direction. Try to move. However, in the plurality of restricting sections, the distance between adjacent restricting sections is set to a length less than the moving amount of the operating piece upstream in the sheet feeding direction. In the middle stage before the paper is moved, the end on the upstream side in the paper feeding direction is locked by any of the plurality of regulating portions, and further movement of the paper to the upstream side in the paper feeding direction is prevented. . Therefore, the movement piece is prevented from moving in the middle of moving the entire desired movement amount, so that the sheet detecting section can correctly detect that there is a sheet on the sheet mounting table.

  According to the present invention, in a paper feeder and an image forming apparatus provided with the same, it is possible to restrict various types of paper having different lengths in the paper feed direction only by selectively loading the paper on the paper mount. There is no need for manual operation such as changing, adjusting or removing the position of the members, and even if the loaded paper has a slight gap with the paper It is possible to correctly detect that there is paper on the mounting table.

FIG. 2 is a cross-sectional view illustrating an image forming apparatus including the sheet feeding device according to the first embodiment. It is a side view which shows typically the periphery of a manual feeder as the paper feeder. It is a top view which shows typically the periphery of the manual insertion device. It is a sectional side view which shows the specific structure which expanded the periphery of the manual feeder. FIG. 4 is an enlarged side sectional view around a sheet presence / absence detection actuator provided in the manual feed device. It is the side sectional view which expanded the circumference of the regulation member with which the manual insertion device is provided. FIG. 10 is a side cross-sectional view illustrating the periphery of a regulating member provided in the manual feed device according to the second embodiment. FIG. 10 is a side sectional view illustrating the vicinity of a regulating member provided in a manual feed device according to a third embodiment.

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

(Embodiment 1)
FIG. 1 is a cross-sectional view illustrating an image forming apparatus including the sheet feeding device according to the first embodiment.

  In FIG. 1, the image forming apparatus 1 has a copying function of reading a document and printing it on a recording sheet, and includes a document reading device 2, a document transport device (ADF) 3, a printing unit 4, and a paper feeding device 5. , A manual feeder (paper feeder) 7, a paper transport unit 8, and the like. The document reading device 2 and the document conveying device 3 are mounted on the upper side of the main body of the image forming device 1, and the printing unit 4, the paper feeding device 5, and the paper conveying unit 8 are built in the main body of the image forming device 1, Further, the manual feed device 7 is attached to a main body side wall of the image forming apparatus 1.

  The image data handled in the image forming apparatus 1 may be one corresponding to a color image using each color of black (K), cyan (C), magenta (M), yellow (Y), or a single color (for example, black). This corresponds to the monochrome image used. For this reason, in the printing unit (image forming unit) 4, each of the developing device 12, the photosensitive drum 13, the drum cleaning device 14, the charging device 15, and the like is formed so that four types of toner images corresponding to each color are formed. And four image stations Pa, Pb, Pc, and Pd, each corresponding to black, cyan, magenta, and yellow.

  In each of the image stations Pa, Pb, Pc, and Pd, after removing and collecting the residual toner on the surface of the photosensitive drum 13 by the drum cleaning device 14, the surface of the photosensitive drum 13 is set to a predetermined potential by the charging device 15. The surface of the photosensitive drum 13 is exposed uniformly by the optical scanning device 11 to form an electrostatic latent image on the surface, and the developing device 12 develops the electrostatic latent image on the surface of the photosensitive drum 13. A toner image is formed on the surface of the photosensitive drum 13. Thus, a toner image of each color is formed on the surface of each photoconductor drum 13.

  Thereafter, the belt cleaning device 22 removes and collects the residual toner on the intermediate transfer belt 21 while rotating the intermediate transfer belt 21 in the direction of the arrow C, and removes the toner image of each color formed on the surface of each photosensitive drum 13. The toner image is transferred to the intermediate transfer belt 21 to form a color toner image on the intermediate transfer belt 21.

  A nip area 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 sandwiched between the nip areas. While being conveyed, the color toner image on the surface of the intermediate transfer belt 21 is transferred onto a recording sheet. Then, the recording sheet is sandwiched between the heating roller 24 and the pressing roller 25 of the fixing device 17 and heated and pressed to fix the color toner image on the recording sheet.

  On the other hand, in the paper transport unit (take-in unit) 8, the recording paper is sent out from the paper feeding device 5 or the manual feed device 7, is transported through the paper transport path R 1, and is taken in. The sheet is conveyed to the sheet discharge tray 39 via the sheet discharge rollers 36 via the fixing device 17. In the paper transport path R1, the recording paper is stopped once, the leading edge of the recording paper is aligned, and then the transport of the recording paper is performed in accordance with the transfer timing of the toner image in the nip area between the intermediate transfer belt 21 and the transfer roller 23a. , Each conveyance roller 35 for urging the conveyance of the recording paper, each paper discharge roller 36, and the like.

  The sheet feeding device 5 includes a cassette 51 disposed below the image forming apparatus 1, a sheet feeding tray 52 on which recording sheets are stacked, a pickup roller 53 provided at one end of the sheet feeding tray 52, and a pickup roller 53. The paper feed roller 54 is disposed downstream in the paper transport direction (hereinafter, referred to as the paper feed direction), and the separation roller 55 is pressed against the paper feed roller 54. 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 passed between the paper feeding roller 54 and the separation roller 55, one by one. The sheet is separated and sent to the sheet transport path R1.

  The manual feed device 7 is disposed on a side wall of the main body of the image forming apparatus 1, and is a manual feed tray (sheet mounting table) 71 on which recording paper (paper) is stacked, and a paper feed provided on one end upper side of the manual feed tray 71. The roller 72, a separation roller 73 pressed against the sheet supply roller 72, and a sheet guide member 74 disposed upstream of the nip area between the sheet supply roller 72 and the separation roller 73 in the recording sheet supply direction. Have. In the manual feed device 7, the rotation of the paper feed roller 72 in the clockwise direction F in the drawing causes the recording paper to pass from the manual feed tray 71 via the paper guide member 74 to the nip area between the paper feed roller 72 and the separation roller 73. The recording paper is passed through the nip area, separated into individual sheets, and sent out to the paper transport path R1.

  Next, the manual feed device 7 which is the first embodiment of the sheet feeding device of the present invention will be described in detail. FIG. 2 is a side view schematically showing the manual feed device 7.

  As shown in FIG. 2, the manual feed tray 71 is disposed so as to be inclined so that a tip portion 71 a thereof is downward, and the tip portion 71 a is provided with a first inclined contact portion 71 b and a second inclined contact portion. The portion 71c and the third inclined contact portion 71d are sequentially provided from the upstream side in the sheet feeding direction E of the recording sheet. On the upper surface of the manual feed tray 71, a pair of guide plates 75 for sandwiching and guiding the recording paper is provided. Each guide plate 75 is provided so as to be movable in a direction orthogonal to the paper feeding direction E, and is symmetrically moved with respect to the center of the manual feed tray 71 by a mechanism (not shown). The center of the sandwiched recording paper is made to coincide with the center of the manual feed tray 71.

  The paper feed roller 72 is disposed above the third inclined contact portion 71d of the tip portion 71a of the manual feed tray 71, and the 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 paper feed roller 72, and the bearing (not shown) of the shaft 73a of the separation roller 73 is moved toward the paper feed roller 72 by a spring (not shown). The separation roller 73 is pressed against the paper feed roller 72 by being urged, and a nip area H is formed between the paper supply roller 72 and the separation roller 73.

  A paper guide member 74 is fixed to the upper end of the third inclined contact portion 71d, and the paper guide member 74 extends to the surface of the paper feed roller 72. Contacting or slightly spaced from a surface.

  FIG. 3 is a plan view schematically showing the periphery of the manual feeding device 7. FIG. 4 is a side view showing a specific configuration in which the area around the manual feed device 7 is enlarged. As shown in FIG. 3, in the manual feed device 7, the manual feed tray 71 is formed in a rectangular shape that is long in a direction perpendicular to the paper feeding direction E (hereinafter, also referred to as a lateral width direction). The length of the manual feed tray 71 in the paper feeding direction E is set near the length of small-sized recording paper, for example, A6 size recording paper. The upper surface of the manual feed tray 71 is formed substantially flat, and this flat surface serves as a mounting surface 71g on which the recording paper is mounted. As shown in FIG. 4, when a small-size recording sheet Ps is placed on the placement surface 71g, the end (hereinafter, also referred to as a rear end) of the recording sheet Ps on the upstream side in the sheet feeding direction E is manually inserted. It is located at the rear end of the tray 71. The pair of guide plates 75 are provided on the placement surface 71g, and the guide plate 75 is used to position the center of the recording sheet on the placement surface 71g on the center line 1 in the lateral width direction.

  Further, on the upstream side of the manual feed tray 71 in the paper feeding direction E, an expansion tray (expansion paper mounting table) 80 formed in a rectangular shape is arranged. The extension tray 80 has two connection portions 80a and 80b that protrude toward the paper feeding direction E at the downstream end (hereinafter also referred to as a front end) in the paper feeding direction E. The two connecting portions 80a and 80b are formed at the left end and the right end (one end and the other end in the direction orthogonal to the sheet feeding direction E) of the extension tray 80, and are formed at the rear end of the manual feed tray 71. It is rotatably supported at a pivot (not shown). As shown in FIG. 4, the two connecting portions 80a and 80b are formed with protruding portions 80c and 80d which protrude upward. The upper surface of the extension tray 80 is formed as a flat surface excluding the raised portions 80c and 80d, and this flat surface serves as a mounting surface 80e on which the rear portion of the large recording paper is mounted.

  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 paper feed roller 72 is located on an extension of the center line 1 of the manual feed tray 71.

  FIG. 4 shows a state where the manual feed tray 71 and the extension tray 80 are opened. Although not shown in detail, the manual feed tray 71 has a lower end rotatably supported by a side wall 1 a forming a main body side wall of the image forming apparatus 1, and the manual feed tray 71 is provided inside the side wall 1 a of the image forming apparatus 1. The manual feed tray 71 is positioned at a closed position in which the manual feed tray 71 is rotated clockwise in FIG. 4 around the pivot point from the closed position.

  On the other hand, the extension tray 80 is stored in the storage position located directly above the manual feed tray 71, and the extension tray 80 is rotated clockwise in FIG. It is positioned at the illustrated extended position forming a continuous mounting surface.

  When recording paper is fed using the manual feeder 7, the manual feed tray 71 is positioned at the open position shown, and the expansion tray 80 is further positioned from the storage position to the expansion 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 is a large-size recording sheet Pl exceeding the rear end of the manual feed tray 71, the front of the large-size recording sheet Pl is moved to the placement surface 71g of the manual feed tray 71. And the rear part thereof is placed on the placement surface 80 e of the extension tray 80. At this time, the rear portion of the large-size recording sheet Pl is lifted upward by contacting the raised portions 80c and 80d formed on the two connection portions 80a and 8b of the extension tray 80, and is placed on the mounting surface 80e. Is placed.

  As can be seen from FIG. 4, when the manual feed tray 71 is at the open position shown in the drawing, its rear end is located above a pivot point (not shown) at the front end, and the entire manual feed tray 71 is fed. It is positioned so as to be inclined at an inclination angle θ1 toward the downstream side in the 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 feeding direction E by its own weight.

  When the expansion tray 80 is also at the expansion position shown in the drawing, its rear end is located above a pivot point (not shown) at the front end, and the entire expansion tray 80 is located on the downstream side in the paper feeding direction E. To be inclined at an inclination angle θ2 toward. The inclination angle θ2 of the extension tray 80 is different from the inclination angle θ1 of the manual feed tray 71, and is set to be larger than the inclination angle θ1 of the manual feed tray 71 (θ2> θ1).

  As shown in FIG. 4, near the front end of the manual feed tray 71, a paper detection unit 90 is disposed so as to face the front end. As shown in FIG. 3, the paper detection unit 90 is arranged on the side of the paper feed roller 72 (a direction orthogonal to the paper feed direction E), and has a paper presence / absence detection actuator (operation piece) 91. .

  As shown in enlarged detail in FIG. 5, the paper presence / absence detecting actuator 91 includes a V-shaped bent plate 91a, a square connecting plate 91b, and a biasing spring 91c. The U-shaped plate 91a is composed of a horizontal plate 91d arranged substantially in parallel with the sheet feeding direction E, and a rising plate 91e rising upward from an upstream end of the horizontal plate 91d in the sheet feeding direction E. The leading ends of the recording papers Ps and Pl on the manual feed tray 71 come into contact with the lower end portion 91e by its own weight or the like. The horizontal plate 91d of the U-shaped plate 91a has a downstream end in the sheet feeding direction E fixed to a shaft 92 provided in the main body of the image forming apparatus 1. The lower end of the connecting plate 91b is also connected to the shaft 92, and a cutout 91f is formed at the upper end of the connecting plate 91b. The urging spring 91c is contracted between the notch 91f and the main body of the image forming apparatus 1.

  In the paper presence / absence detection actuator 91, the urging force (predetermined pressure) of the urging spring 91c causes the connecting plate 91b to rotate around the shaft 92 toward the upstream side in the paper feeding direction E, and accordingly, the shaft 92 By rotating clockwise, the U-shaped plate 91a rotates toward the upstream side in the paper feeding direction E, and the leading ends of the recording sheets Ps and Pl on the manual feed tray 71 are moved to the upstream side in the paper feeding direction E. Push back.

  When there is no recording paper Ps, Pl on the mounting surface 71g of the manual feed tray 71, the V-shaped plate 91a of the paper presence detection actuator 91 rotates toward the upstream side in the paper feeding direction E by the urging force of the urging spring 91c. It is positioned at the specified initial position. On the other hand, when there are a large number of small-sized recording sheets Ps or a large-sized recording sheet Pl on the mounting surface 71g of the manual feed tray 71, the U-shaped plate 91a is located on the downstream side in the sheet feeding direction E due to its own weight of the recording sheets Ps. In response to the pressure, the urging spring 91c is rotated toward the downstream side in the paper feeding direction E while being contracted, and deviates from the initial position. The paper detection unit 90 has a position sensor (not shown) for detecting the position of the V-shaped plate 91a of the paper presence / absence detection actuator 91. When the V-shaped plate 91a is at the initial position, It is detected that there is no recording paper Ps, Pl on the mounting surface 71g, and it is detected that there is recording paper Ps, Pl when it deviates from the initial position.

  In the paper presence / absence detection actuator 91, the urging spring 91c is completely reduced by the amount of movement of the V-shaped plate 91a, that is, from the initial position, by pressing the recording papers Ps and Pl toward the downstream in the paper feeding direction E by its own weight. The amount of movement to the pressed position where the L-shaped plate 91a is rotated in the state in which it is made to move is set to, for example, about 1.5 mm, which is 2 mm or less.

  As shown in FIG. 3, near the rear end of the manual feed tray 71, that is, near the connection between the manual feed tray 71 and the extension tray 80, the small-size recording paper placed on the loading surface 71g. Two regulating members 100 for regulating the movement of Ps to the upstream side in the paper feeding direction E are arranged. The restricting member 100 is located in a space where the two connecting portions 80a and 80b of the extension tray 80 are sandwiched in a direction orthogonal to the sheet feeding direction E. The two regulating members 100 are arranged one by one in the left-right direction (the direction orthogonal to the sheet feeding direction E) with the center line 1 of the manual feed tray 71 interposed therebetween. Therefore, the two regulating members 100 are located symmetrically with respect to the paper feed roller 72 on the center line l. 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 minimum lateral width is positioned on the center line 1 by the pair of guide plates 75. Further, one regulating member 100 is located on a line extending the arrangement position of the sheet presence detection actuator 91 toward the upstream side in the sheet feeding direction E.

  The two regulating members 100 have the same structure. FIG. 6 is an enlarged side sectional view showing the periphery of the regulating member 100.

  In FIG. 6, the regulating member 100 is formed in a saw-like shape in which a large number of blades are continuously arranged in a straight line on the paper feeding direction E side. Each of the large number of blades constitutes a restricting portion 101 that restricts the rear end of various recording sheets Ps having different lengths in the paper feeding direction E from moving upstream in the paper feeding direction E. Each restricting portion 101 has a cut surface 101a that is cut in a substantially vertical direction when the manual feed tray 71 is tilted at the tilt angle θ1, and a rear slope 101b that descends obliquely downward and rearward from the top of the cut surface 101a. The cut surface 101a faces the rear end of the recording paper Ps on the manual feed tray 71, and when the recording paper Ps moves upstream in the paper feeding direction E, the rear end surface of the recording paper Ps becomes the cut surface 101a. It has a function of contacting and restricting or preventing the movement in the paper feeding direction E upstream.

  The plurality of regulating portions 101 are different from each other in height h from the mounting surface 71g of the manual feed tray 71, that is, the length from the mounting surface 71g to the vertex of the cut surface 101a is different from each other. Are arranged such that the height h becomes higher as the restricting portion 101 is located at the position.

  In the large number of restricting portions 101, the distance S between two adjacent restricting portions 101, that is, the distance between the vertices of the cut surface 101a is determined from the initial position of the V-shaped plate 91a of the paper presence detecting actuator 91. The length is set to be less than the movement amount to the pressing position. For example, when the moving amount of the V-shaped plate 91a of the paper presence detecting actuator 91 is set to 2 mm, the length is set to less than 2 mm, for example, 1.2 mm. The distance S does not need to be set to the same length (equal pitch) between two adjacent regulating portions 101, and the point is that it is set to a length less than the movement amount of the square plate 91a. Just do it.

  Further, the difference d between the heights h of the apexes of the cut surfaces 101a between two adjacent regulating portions 101 is set to a thickness of about two sheets of recording paper Ps placed on the manual feed tray 71. You.

  In the regulating member 100, the length in the sheet feeding direction E, that is, the entire length of the plurality of regulating portions 101 is set to, for example, about 15 mm in the present embodiment.

  Although FIG. 6 illustrates a case where fifteen regulating parts 101 are arranged, the number of arrangements can be appropriately set.

  As described above, in the present embodiment, when the small-sized recording paper Ps is supplied into the image forming apparatus 1 using the manual feed device 7, the manual feed tray 71 is positioned at the open position, and the expansion tray 80 is positioned at the expanded position. In this state, the recording paper Ps is placed on the placement surface 71g of the manual feed tray 71.

  In this state, when the number of recording sheets Ps is large, since the manual feed tray 71 is inclined toward the downstream side at the inclination angle θ1, the recording sheet Ps moves downstream in the sheet feeding direction E by its own weight. For this reason, in the sheet presence detection actuator 91, the U-shaped plate 91a receives the pressing of the recording sheet Ps on the downstream side in the sheet feeding direction E by its own weight, and resists the urging force of the urging spring 91c in the sheet feeding direction E. To the side and deviate from the initial position. Therefore, the paper detecting unit 90 detects that the recording paper Ps is present in the manual feed tray 71. In this state, the rear end of the recording paper Ps is located within the range of arrangement of the many restricting portions 101 of the restricting member 100 at the rear end of the manual feed tray 71.

  On the other hand, the number of recording sheets Ps on the manual feed tray 71 is, for example, one or two, and the pressing of the recording paper Ps toward the downstream in the paper feeding direction E by its own weight is caused by the urging force of the urging spring 91 c of the paper presence detecting actuator 91. Is smaller, the U-shaped plate 91a of the sheet presence detection actuator 91 is rotated toward the initial position in the paper feeding direction E upstream, and the recording paper Ps is pushed back to the paper feeding direction E upstream. Become. However, when the rear end portion of the recording sheet Ps comes into contact with the cut surface 101a of any one of the plurality of regulating portions 101, the movement further upstream in the sheet feeding direction E is restricted by the regulating portion 101. Therefore, the sheet presence detecting actuator 91 does not move to the initial position. Therefore, the paper detection unit 90 reliably and correctly detects that the recording paper Ps is present in the manual feed tray 71.

  Here, the restricting member 100 is composed of a plurality of restricting portions 101, and is arranged such that the height h of the restricting portions 101 from the mounting surface 71g of the manual feed tray 71 becomes higher toward the upstream side in the sheet feeding direction E. Have been. 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 trailing end of the placed recording paper Ps is Of the plurality of regulating portions 101, the vicinity of the apex of the cut surface 101a of the nearest regulating portion 101 that is first located upstream from the trailing end of the recording sheet Ps in the paper feeding direction E (the immediately preceding regulation portion). (D portion of the height h with respect to the portion 101) is securely contacted and locked, so that the regulating member 100 is moved to the upstream side in the paper feeding direction E or the conventional manner every time the recording paper Ps is placed. There is no need to move and adjust downstream.

  Therefore, even if the recording paper Ps placed on the manual feed tray 71 is a fixed size paper such as a postcard, for example, there is a tolerance (for example, about 1.5 mm), or a case where a plurality of recording papers Ps are placed. In the case where some misalignment has occurred on the paper feeding direction E side, and even if various customized papers having different lengths in the paper feeding direction E are selectively loaded, Even if the number of the recording sheets Ps is one or two, it can be correctly detected that the recording sheet Ps exists on the mounting surface 71g.

  In addition, since the cut surface 101a of any one of the plurality of restricting portions 101 abuts on the rear end surface of the recording sheet Ps to prevent its movement to the upstream side in the sheet feeding direction E, the recording is performed. Even when the paper Ps is slightly floating from the mounting surface 71g of the manual feed tray 71, a friction member is disposed on the mounting surface as in the related art and the movement is suppressed by the frictional force with the lower surface of the paper. In addition, it is possible to reliably prevent the recording paper Ps from moving upstream in the paper feeding direction E.

  When there is no recording paper Ps in the manual feed tray 71, the V-shaped plate 91a of the paper presence / absence detection actuator 91 is positioned at the initial position by the urging force of the urging spring 91c. Is correctly detected that there is no recording paper Ps.

  In the present embodiment, the regulating member 100 is disposed at the rear end of the manual feed tray 71, that is, around the connection between the manual feed tray 71 and the extension tray 80, and the inclination angle θ2 of the extension tray 80 is set to the inclination angle of the manual tray 71. It is set to be larger than θ1 (θ2> θ1). Therefore, when the large-sized recording paper Pl is placed across the mounting surface 71g of the manual feed tray 71 and the mounting surface 80e of the extension tray 80, as shown in FIG. As a result, an empty space P is formed around the connection between the manual feed tray 71 and the extension tray 80 and the recording paper Pl, and the regulating member 100 is located in the empty space P. Therefore, when the large-sized recording paper Pl is fed, the regulating member 100 does not interfere with the operation of moving the recording paper Pl in the paper feeding direction E. Therefore, large-sized recording paper Pl can be easily fed without requiring manual operation such as removing the regulating member 100.

  When a large-sized recording sheet Pl is placed, its own weight is heavier than that of the small-sized recording sheet Ps. Therefore, even if the recording sheet Pl is one or two sheets, the presence or absence of the sheet is detected by its own weight. Since the V-shaped plate 91a of the actuator 91 rotates downstream in the sheet feeding direction E against the urging force of the urging spring 91c, it deviates from the initial position. Therefore, the sheet detection unit 90 correctly detects that one or two large-size recording sheets Pl are placed.

  Further, in the present embodiment, in the plurality of restricting portions 101 of the restricting member 100, the distance between the adjacent restricting portions 101 is determined by the operation amount of the sheet presence detecting actuator 91, that is, the pressing position of the L-shaped plate 91a. The length (for example, 1.2 mm) is set to be less than the movement amount (for example, 2 mm) to the initial position. Therefore, even if the U-shaped plate 91a of the paper presence detecting actuator 91 pushes the recording paper Ps back to the upstream side in the paper feeding direction E by the urging spring 91c, the U-shaped plate 91a reaches the initial position, The trailing end of the recording sheet Ps is locked to one of the cut surfaces 101a of the plurality of regulating portions 101, and further movement to the upstream side in the sheet feeding direction E is prevented. Therefore, the V-shaped plate 91a of the sheet presence detection actuator 91 does not reach the initial position, and the sheet detection unit 90 correctly detects that the recording sheet Ps is present on the manual feed tray 71.

  Further, in the present embodiment, the two regulating members 100 are arranged on both left and right sides of the center line 1 within the width of the small-sized recording paper Ps placed on the manual feed tray 71. Therefore, even if the sheet presence detection actuator 91 pushes back the leading end of the recording sheet Ps at a position shifted from the center line l, the recording sheet Ps is positioned symmetrically with respect to the center line l by the two regulating members 100. , And the occurrence of a position shift to the left or right is suppressed.

(Embodiment 2)
FIG. 7 shows a main part of the sheet feeding device according to the second embodiment.

  In the first embodiment, the regulating member 100 is formed in a saw shape, but in the present embodiment, the regulating member 100 is formed in a comb shape.

  That is, in the regulating member 100 shown in FIG. 7, a plurality of combs extending in a line toward the upstream side in the paper feeding direction E are provided at the rear end of the manual feed tray 71, and these combs are used as the plurality of regulating portions 101. Things. Each of the plurality of restricting portions 101 is formed in a rectangular shape extending upward from the mounting surface 71g, and is arranged such that the height from the mounting surface 71g increases toward the upstream in the sheet feeding direction E. This is the same as in the first embodiment.

(Embodiment 3)
FIG. 8 shows a main part of the sheet feeding device according to the third embodiment.

  In the present embodiment, the regulating member 100 is formed in a brush shape. That is, in FIG. 8, a large number of linear bristle materials extending upward from the mounting surface 71g are arranged in the sheet feeding direction E side and the width direction, and the large number of bristle materials are used as a large number of regulating portions 101 to form the large number of bristle materials. The restricting portion 101 is arranged such that the height from the mounting surface 71g becomes higher toward the upstream side in the paper feeding direction E.

  In the present embodiment, since a large number of the regulating portions 101 are arranged toward the upstream side in the paper feeding direction E, the pushing back amount of the recording paper Ps placed on the manual feed tray 71 to the upstream side in the paper feeding direction E is minimized. It is possible to suppress to the limit.

  In the above description, the regulating member 100 has a saw-like shape, a comb-like shape, and a brush-like shape, but may have a step-like shape or a plurality of continuous rib-like shapes. Further, a sponge, a high-friction sheet, or a magic tape (registered trademark) may be used so that the shape thereof becomes higher toward the upstream side in the sheet feeding direction E.

  In the above embodiment, the present invention is applied to the manual feeder 7. However, the present invention is also applied to the original reading device 2 and the original transporting device 3 so that the presence / absence of the original sheet placed on the original reading device 2 and the original conveying device 3 can be correctly detected. Of course, you can do so.

  The present invention may be embodied in various other forms without departing from its spirit or essential characteristics. Therefore, the above-described embodiment is merely an example and should not be construed as limiting. All modifications and changes belonging to the equivalent scope of the claims of the present invention are within the scope of the present invention.

  The present invention provides, as a paper feeding device, one sheet or two sheets of paper on a paper mounting table without any manual operation such as changing, adjusting, or removing the position of a regulating member disposed on the paper mounting table. Even when the number of sheets is reduced, it is possible to reliably detect that there is a sheet on the sheet mounting table, and thus the present invention is useful when applied to a sheet feeding device and an image forming apparatus including the same.

1 image forming apparatus 4 printing unit (image forming unit)
7 Manual feeder (paper feeder)
71 Bypass tray (paper loading table)
71g Loading surface E Paper feed direction 72 Paper feed roller 8 Paper transport unit (take-in unit)
80 Expansion tray (expansion paper table)
80a Connection part 80e Mounting surface 90 Paper detection part 91 Paper presence detection actuator (moving piece)
91a rectangular plate 91c biasing spring Ps small-sized recording paper (paper)
Pl Large-size recording paper (paper)
100 regulating member 101 regulating portion 101a cut face

Claims (7)

A paper supply device for supplying paper to the image forming apparatus,
A sheet placing table on which a sheet is placed, and which is inclined downward toward a downstream side in a sheet feeding direction for supplying the sheet to the image forming apparatus;
A sheet detecting unit that has an operation piece that presses the downstream end of the sheet in the sheet feeding direction at a predetermined pressure on the upstream side in the sheet feeding direction, and detects the presence or absence of the sheet by the operation of the operation piece;
A regulating member disposed near an end of the paper mounting table on the upstream side in the paper supply direction, and a regulating member for regulating movement of the paper to the upstream side in the paper supply direction,
The regulating member has a plurality of regulating portions having different heights from the placing surface of the paper placing table,
The paper feeding device according to claim 1, wherein the plurality of restricting portions are arranged such that the height increases toward an upstream side in the paper feeding direction. The paper mounting table is a manual feed tray,
The sheet feeding device according to claim 1, wherein a plurality of types of sheets having different lengths in the sheet feeding direction are selectively placed on the manual feed tray. At the end of the paper mounting table on the upstream side in the paper feeding direction, an extended paper mounting table for large paper that is inclined downward toward the downstream side in the paper feeding direction is connected,
The angle of the inclination of the expansion sheet mounting table is set to be larger than the angle of the inclination of the sheet mounting table,
The paper feeder according to claim 1, wherein the restricting member is disposed at a position near a connection between the paper mounting table and the extended paper mounting table. 4. The said restriction member is arrange | positioned in the width | variety of the direction orthogonal to the said paper feed direction of the said paper, and is arrange | positioned on both sides on either side of the center of the said width. 2. The paper feeding device according to claim 1. The distance between the adjacent regulating portions of the plurality of regulating portions is set to a length less than the amount of movement of the operation piece toward the upstream side in the sheet feeding direction. The paper feeding device according to claim 4. The paper feeder according to any one of claims 1 to 5, wherein the plurality of regulating portions are formed in a step shape, a comb shape, or a brush shape. A sheet feeding device according to any one of claims 1 to 6,
An intake unit that takes in the sheet placed on the sheet placing table,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet captured by the capturing unit.

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