JP4452147B2 - Paper feeding device and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding device that supplies a predetermined recording sheet such as a single sheet to a printing apparatus or the like, and an image forming apparatus equipped with the sheet feeding device.

  Conventionally, various paper feeding apparatuses that set a plurality of recording sheets in a sheet cassette and supply these recording sheets to a printing apparatus or the like have been proposed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-41187

  This Patent Document 1 includes a sheet material feeder unit having a sheet material feeding unit, and a sheet material storage unit that is detachably attached to the sheet material feeder unit, and for an apparatus main body that processes the sheet material, A sheet material feeding device that sequentially feeds sheet materials stored in a sheet material storage unit by sheet material feeding means is disclosed. In particular, in this sheet material feeding apparatus, the sheet material storage unit includes a sheet receive plate that can be rotated up and down by stacking sheet materials, a side guide that can be moved according to the size of the sheet material, and a sheet receive plate. A first pressure spring that can be pressed upward and is held in a non-engagement position with the sheet receive plate according to the movement position of the side guide, and an inner side in the sheet material width direction than the first pressure spring And a second pressure spring that presses the seat receive plate upward.

  Specifically, in this sheet material feeding device, when the side guide is moved to the outer position where the recording paper size is large by the first pressure spring, the sheet receiving plate is pressed upward. When the side guide is moved to an inner position where the recording paper size is small, the sheet receiving plate is held so as not to be pressed upward, and the second pressure spring is used regardless of the recording paper size. Press the sheet receive plate upward. As a result, in this sheet material feeding apparatus, the pressure spring can be selected by moving the side guide, so that it is possible to suppress a change in the sheet feeding pressure due to a difference in weight depending on the recording sheet size. It is said that stable feeding without feeding and non-feeding can be performed.

  However, in the conventional apparatus described in Patent Document 1 described above, it is necessary to use a plurality of pressure springs that press the sheet receive plate upward in accordance with the recording paper size, and the side guide is positioned at the position of the side guide. Accordingly, there is a problem that the cost increases due to the large number of parts, such as the need for a mechanism for holding these pressure springs. In the conventional apparatus for setting the recording paper in a state close to horizontal, the force obtained by subtracting the paper weight from the tension uniquely determined based on the amount of bending of the spring becomes the pressing force. However, if the weight of the recording paper is different with the same stacking thickness due to the difference in the bulk and density of the recording paper, there is a problem that the optimum pressing force cannot be obtained, which is technically satisfactory. It was not a thing.

  The present invention has been made in view of such circumstances, and although it has a simple configuration, it is possible to appropriately adjust the pressing force of the plate on which the recording paper is stacked, and to realize stable paper feeding performance. It is an object of the present invention to provide a sheet feeding device that can perform the operation and an image forming apparatus equipped with the sheet feeding device.

A sheet feeding device according to the present invention that achieves the above-described object is capable of moving according to the width of the recording sheet and a stacking plate on which a plurality of predetermined recording sheets are stacked, and restricts the width direction of the recording sheet. A plurality of urging means for urging the stacking plate with respect to a paper feed roller that is provided at both ends in the width direction of the recording medium and feeds out the recording sheets stacked on the stacking plate; A sliding member supported so as to be slidable with respect to the loading plate; and a lever member supported so as to be able to rotate with respect to the restriction member, and depending on the position of the restriction member, A pressing force changing unit that changes a pressing force of the stacking plate with respect to the sheet feeding roller; and a pressing force adjusting unit that adjusts the pressing force by the pressing force changing unit, and one end portion of the biasing unit has the lever member The other end is It is characterized by being engaged with the member.

  In such a paper feeding device according to the present invention, the pressing force by the urging means for generating the pressing force of the stacking plate can be changed according to the change operation of the size of the recording paper. Accordingly, in the paper feeding device according to the present invention, the paper feeding rollers provided on both ends in the width direction of the recording medium, from large recording paper to small recording paper, respectively, feed the recording paper stacked on the stacking plate. Thus, the pressing force can be changed to the optimum pressing force for the sheet feeding operation by a plurality of urging means for urging the stacking plate. In the paper feeding device according to the present invention, even if the pressing force by the set biasing means deviates from an appropriate value due to the difference in density and bulk of the recording paper, the paper feeding device by the pressing force adjusting means. The deviation from the optimum value of the pressing force of the recording paper against the roller can be supplemented.

  Here, the pressing force adjusting means is configured to be able to adjust the pressing force for each recording paper size regardless of the position of the restricting member. As a result, the paper feeding apparatus according to the present invention can perform a stable paper feeding operation without complicating the structure.

  Further, as the biasing means, a predetermined elastic body provided in a paper feed cassette as the paper feed device configured to be detachable from the apparatus main body can be used. In this case, the pressing force adjusting means can be provided in the paper feeding cassette.

  Further, as the urging means, a predetermined elastic body provided on the apparatus main body that allows the sheet feeding cassette as the sheet feeding apparatus to be detachable can be used. In this case, the pressing force adjusting means can be provided in the paper feeding cassette. As described above, in the paper feeding device according to the present invention, the structure of the paper feeding cassette can be simplified by providing the biasing means in the device main body.

  The apparatus main body is preferably applied with an image forming apparatus that forms an image on the recording paper or a hopper device that sets the recording paper as a read original in a reading apparatus that reads original information.

An image forming apparatus according to the present invention that achieves the above-described object is an image forming apparatus that forms an image on a predetermined recording sheet. The image forming apparatus includes at least an apparatus main body having image forming means, and the apparatus main body. A paper feeding device for feeding recording paper, the paper feeding device being capable of moving according to the width of the recording paper, a stacking plate for stacking a plurality of the recording paper, and the width direction of the recording paper A plurality of urging means for urging the stacking plate with respect to a sheet feeding roller that feeds out the recording sheets stacked on the stacking plate, respectively. And a sliding member supported to be slidable with respect to the loading plate, and a lever member supported to be rotatable with respect to the regulating member, and depending on the position of the regulating member, On the paper feeding roller by means Wherein a pressing force changing means for changing the pressing force of the loading plate, and a pressing force adjusting means for adjusting the pressing force by the pressing force varying means, one end of said biasing means engaging said lever member The other end is locked to the sliding member .

Furthermore, an image forming apparatus according to the present invention that achieves the above-described object has an image forming unit that forms an image on a predetermined recording sheet, and feeds the recording sheet to the apparatus main body. In the image forming apparatus, the sheet feeding device includes a stacking plate on which a plurality of the recording sheets are stacked, and a regulating member that is movable in accordance with the width of the recording sheets and regulates the width direction of the recording sheets. A plurality of urging means respectively provided at both ends in the width direction of the recording medium and urging the stacking plate against a feed roller for feeding out the recording sheets stacked on the stacking plate; And a lever member supported to be rotatable with respect to the regulating member, and depending on the position of the regulating member, the paper feeding by the urging means The pressing force of the loading plate against the roller And a pressing force adjusting means for adjusting the pressing force by the pressing force changing means, wherein the apparatus main body has the recording position where the contact position of the lever member is stacked on the stacking plate. A contact portion having an inclined surface is provided so as to be movable toward the center of the recording paper in the width direction of the paper for a while, and one end of the urging means is locked to the lever member. The other end is locked to the sliding member.

  In such an image forming apparatus according to the present invention, the pressing force by the urging means for generating the pressing force of the stacking plate can be changed according to the operation of changing the size of the recording paper. Therefore, in the image forming apparatus according to the present invention, the recording roller is provided at both ends in the width direction of the recording medium, from a large recording sheet to a small recording sheet, and feeds the recording sheets stacked on the stacking plate. Thus, the pressing force can be changed to the optimum pressing force for the sheet feeding operation by a plurality of urging means for urging the stacking plate. In the image forming apparatus according to the present invention, even if the pressing force by the set urging means deviates from an appropriate value due to the difference in density and bulk of the recording paper, the paper is fed by the pressing force adjusting means. The deviation from the optimum value of the pressing force of the recording paper against the roller can be supplemented.

  In the present invention, since it is possible to change the optimum pressing force for the paper feeding operation by one type of biasing means from a large size recording paper to a small size recording paper, the recording paper has a simple and inexpensive configuration. It is possible to appropriately adjust the pressing force of the loading plate on which the paper is loaded, and to realize stable paper feeding performance.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  This embodiment is a printing apparatus as an image forming apparatus that forms an image on a predetermined recording medium. In particular, this printing apparatus is equipped with a paper feeding device that feeds recording paper as a recording medium loaded in a paper feeding cassette, and has a simple configuration, but the pressing force of a plate on which recording paper is loaded Can be adjusted appropriately.

  First, the printing apparatus shown as the first embodiment will be described.

  As shown in FIG. 1, the printing apparatus includes a paper feed cassette 1 as a paper feed device that stores recording paper P as a recording medium. The paper feed cassette 1 is detachably installed at the lower part of the printing apparatus main body, and a sheet receive plate 2 to be described later on which a plurality of recording papers P are stacked and stacked is provided therein. The recording sheets P stacked on the sheet receiving plate 2 are fed out from the sheet feeding cassette 1 one by one by being pressed against the rotating sheet feeding roller 3 and arranged in a sheet conveying path inside the printing apparatus. In accordance with the rotation of the transport roller 4 that has been performed, the transport roller 4 is transported to an image forming unit 5 described later.

  In addition, the printing apparatus includes an image forming unit 5 that forms an image on the recording paper P downstream of the conveyance roller 4. The image forming unit 5 includes, for example, an image drum (not shown) corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K), a transfer roller for transferring a toner image, and the like. The image forming unit 5 forms an electrostatic latent image on the photosensitive drum stored in the image drum, develops the electrostatic latent image with toner to form a toner image, and then forms a toner image on the photosensitive drum. Is transferred onto the recording paper P.

  The printing apparatus further includes a fixing unit 6 that fixes the toner image formed on the recording paper P by the image forming unit 5 to the recording paper P. The fixing unit 6 includes, for example, a heater, a pressure roller, and the like, and fixes the toner image on the recording paper P by heat and pressure. In the printing apparatus, when the image is fixed on the recording paper P, the recording paper P is transported and discharged to the outside.

  In such a printing apparatus, a sheet feeding cassette 1 used for the sheet feeding apparatus is configured as shown in a perspective view of a main part in FIG. That is, the paper feed cassette 1 can be attached / detached by sliding it in the directions of arrows A and A ′ in the drawing with respect to the paper feed cassette mounting portion provided in the printing apparatus main body. The sheet feed cassette 1 is provided with the above-described sheet receive plate 2 as a stacking plate on which a plurality of recording sheets P are stacked in a box-shaped cassette case 11. The sheet receive plate 2 is rotated with respect to a support shaft protruding from the inner surface of the cassette case 11 by two rotation support points 12 (one is not shown) provided coaxially at one end thereof. It is pivotally supported. The sheet receiving plate 2 has a central portion at the other end of the sheet receiving plate 2 opposite to the rotation fulcrum 12. When the sheet feeding cassette 1 is mounted at a predetermined position of the printing apparatus main body, A frictional separation piece 13 made of rubber, cork, or the like is fixed to the contact position.

  Further, on the bottom surface of the cassette case 11, a pair of left and right paper side guides 14 (one portion is not shown) configured to be slidable in the direction of arrow B in FIG. It has been. These sheet side guides 14 are supported by an operation mechanism (not shown) such as a rack-pinion mechanism so as to be slidable symmetrically with respect to a printing reference position of the printing apparatus such as a center line in the feeding direction of the recording sheet P. In addition, it is configured to be fixed at a predetermined position according to the size of the recording paper P by a holding means (not shown). That is, these sheet side guides 14 are configured to be movable according to the width of the recording sheet P, and are configured as regulating members that regulate the width direction of the recording sheet P. Further, the sheet side guide 14 is formed with a closing portion 14a so as not to hinder the side portion 2a of the other end portion of the sheet receive plate 2 from rotating up and down.

  Further, the paper feed cassette 1 is provided with a pair of left and right sliding blocks 15 (one place is not shown) that slides on the paper side guide 14. These sliding blocks 15 are engaged by sliding grooves 16a and 16b so as to follow the vertical rotation of the sheet receiving plate 2 and to be slidable in the vertical direction with respect to the opening 14a. Further, the sliding block 15 slides with the side portion 2a of the sheet receiving plate 2 by the groove 17 as the paper side guide 14 slides in the direction of arrow B in FIG. It is supported so as to be movable in the direction of arrow B in the figure. Further, a pair of left and right tension coil springs 18 (one portion is not shown), which is an urging means for urging the sheet receiving plate 2 in the direction of the sheet feeding roller 3 (upward), is provided above the sliding block 15. A hook is formed to engage the one end 18a.

  Further, a pressing force adjusting means in which a support shaft 19 is formed at a position above the end of the sheet side guide 14 on the downstream side in the sheet feeding direction and outside the position for guiding the side surface of the recording sheet P. A pair of left and right pressing force adjustment blocks 20 (one portion is not shown) is supported. As shown in FIG. 3, these pressing force adjusting blocks 20 are formed in a shape in which two oval dies are connected above the vicinity of the end of the paper side guide 14 on the downstream side in the feeding direction of the recording paper P. It is attached to the paper side guide 14 through the block moving oval hole 14b. The pressing force adjusting block 20 is movable in the front-rear direction with respect to the block moving oval hole 14b, and as shown in FIG. 4 (a), an upper portion forming the block moving oval hole 14b. As shown in FIG. 4B, the paper side guide 14 is integrally locked at any one of the first position that is the hole and the second position that is the lower hole. Is supported to be. In such a pressing force adjusting block 20, the operator moves the pressing force adjusting block 20 in a vertical direction with a predetermined force, and the first position shown in FIG. 4A or FIG. By operating to be locked at the second position shown, the position can be changed. In addition, the broken line part in FIG.4 (b) has shown the case where the block 20 for pressing force adjustment is supported by the 1st position shown to Fig.4 (a).

  Further, one end portion 21a of a pair of left and right pressing levers 21 (one portion is not shown) is pivotally supported on the support shaft 19 formed in the pressing force adjusting block 20. On the other hand, the other end portion 18 b of the tension coil spring 18 for urging the sheet receiving plate 2 in the direction of the paper feed roller 3 (upward) is engaged with the other end portion 21 b of the pressing lever 21. . Accordingly, the tension coil spring 18 extends when the other end 21b of the pressing lever 21 rotates upward, and the friction separating piece 13 fixed to the sheet receiving plate 2 is brought into contact with the sheet feeding roller 3 to be attached. To force.

  Furthermore, as shown in FIG. 5, the paper cassette 1 is printed on the paper cassette 1 from the state where the paper cassette 1 is not attached to the printing apparatus main body, as shown in FIG. When attached to the apparatus main body, the press lever 21 is brought into contact with the other end 21b of the press lever 21 at a position corresponding to the other end 21b of the press lever 21 in the printing apparatus main body, and the press lever 21 is moved upward. A pair of left and right projections 22 (one portion is not shown) for biasing the sheet receiving plate 2 in the direction (upward) of the paper feed roller 3 by being rotated are formed. These protrusions 22 are configured such that the sheet receiving plate 2 is automatically pressed in the direction of the paper feed roller 3 by an operation immediately before the paper feed cassette 1 is completely attached to the printing apparatus main body. . Further, in the printing apparatus, the recording paper P having a standard density with respect to the paper feed roller 3 is normally held by locking the position of the pressing force adjusting block 20 to the first position described above. The tension of the tension coil spring 18 is set so as to be biased with an appropriate pressing force. The other end 21 b of the pressing lever 21 has a predetermined elevation angle so that the pressing lever 21 is always rotated upward by the mounting operation of the sheet feeding cassette 1.

  Further, the protrusion 22 has an inclined surface so that the position where the other end 21b of the pressing lever 21 abuts moves toward the center of the recording paper P, that is, inward, for a while. Therefore, when the size of the recording paper P is large and the position of the paper side guide 14 is on the outer side in the paper width direction, the protrusion 22 is not limited to the pressing lever 21 as shown by the solid line portion in FIG. While the amount of extension of the tension coil spring 18 increases after the end 21b abuts against the protrusion 22, the size of the recording paper P is small, and the position of the paper side guide 14 is directed in the paper width direction. If it is on the inner side, as shown by the broken line portion in the figure, the amount of extension of the tension coil spring 18 is reduced. As described above, the pressing lever 21 and the protrusion 22 are configured as pressing force changing means for changing the pressing force of the recording paper P against the paper feeding roller 3 by the tension coil spring 18 according to the position of the paper side guide 14.

  In a printing apparatus in which such a paper feeding cassette 1 is mounted, when recording paper P is supplied to the printing apparatus, a plurality of recording papers P are supplied to the sheet receiving plate 2 in the paper feeding cassette 1. The paper side guide 14 is loaded in the direction of arrow B in FIG. 2 according to the width of the loaded recording paper P, and is fixed by a holding means (not shown).

  In the printing apparatus, when the paper feed cassette 1 is mounted on the printing apparatus main body by sliding it in the direction of arrow A in FIG. 2, the other end of the pressing lever 21 is moved immediately before the mounting is completed. The part 21b is rotated upward, and the tension coil spring 18 is extended. In the printing apparatus, the sliding block 15 moves along the opening 14a of the paper side guide 14 via the sliding grooves 16a and 16b by the tension when the tension coil spring 18 is extended, and the sheet receiving plate 2 is moved. The side portion 2a is urged upward, and the leading end portion of the stacked recording paper P acts to abut against the paper feed roller 3 in the printing apparatus main body.

  Further, in the printing apparatus, when changing the size of the recording paper P, the paper cassette 1 is removed from the main body of the printing apparatus, and then the holding means (not shown) of the paper side guide 14 is released and FIG. By sliding in the direction of the middle arrow B, the paper side guide 14 is fixed again at a position suitable for a predetermined paper size. At this time, the pressing lever 21 supported by the support shaft 20 at the upper end of the paper side guide 14 also moves as the paper side guide 14 moves. The sliding block 15 engages with the opening portion 14a of the sheet side guide 14 through the sliding grooves 16a and 16b, and slides with respect to the side portion 2a of the sheet receiving plate 2 through the groove 17. The sheet side guide 14 moves as the sheet side guide 14 moves.

  In the printing apparatus, when the recording paper P having a different size is set in the paper feeding cassette 1 and the paper feeding cassette 1 is mounted, the paper lever in the paper width direction of the pressing lever 21 according to the position of the paper side guide 14. Since the position of the press lever 21 is changed, an upward direction after the other end portion 21b of the press lever 21 comes into contact by the action of the inclined surface of the projection portion 22 of the printing apparatus main body with which the other end portion 21b of the press lever 21 comes into contact. And the tension of the tension coil spring 18 changes according to the position where the paper side guide 14 is fixed. That is, in the printing apparatus, when the recording paper P having a large paper width is set, the protrusion 22 is present in the front and acts so that the tension of the tension coil spring 18 is increased, while the paper width is small. When the recording paper P is set, the position of the paper side guide 14 is on the inner side in the paper width direction, so that the projection 22 exists on the rear side, and acts to weaken the tension of the tension coil spring 18. To do.

  Further, in the printing apparatus, when the recording paper P having the same size and having a low density and a large bulk is used, the extension amount of the tension coil spring 18 is larger than when the normal recording paper P is set. And a large tension acts, and the pressing force for pressing the recording paper P against the paper feed roller 3 may deviate from an appropriate value. In such a case, in the printing apparatus, the operator moves the pressing force adjusting block 20 so as to be locked at the above-described second position, so that the setting position of the pressing lever 21 is lower than usual. The tension of the tension coil spring 18 can be reduced so that the recording paper P is urged against the paper feed roller 3 with an appropriate pressing force.

  Here, in the printing apparatus, the recording paper P loaded on the sheet receiving plate 2 is moved relative to the paper feed roller 3 by appropriately setting the inclination of the protrusion 22 and the tension of the tension coil spring 18. The pressing force to be pressed is set to an appropriate range for performing a normal paper feeding operation according to the size of the recording paper P and the loading amount of the recording paper P.

  Specifically, as shown in FIG. 4A, when the pressing force adjusting block 20 is set to the normal position, that is, the first position described above, the pressing force and the recording on the sheet feeding roller 3 are recorded. The pressing of the recording paper P stacked on the sheet receiving plate 2 against the paper feed roller 3 so that the relationship with the stacking thickness (bulk) of the paper P becomes the relationship shown in FIG. Set the pressure. That is, in the printing apparatus, when a large size recording paper P is used, as indicated by the line LA in FIG. The pressing force by which the recording paper P stacked on the sheet receiving plate 2 is pressed against the paper feed roller 3 is set so that the pressing force is a pressing force that maintains the lower limit value or more of the appropriate range. Further, in the printing apparatus, when the recording paper P having a small size is used, as shown by a line segment LB in FIG. The pressing force with which the recording paper P loaded on the sheet receiving plate 2 is pressed against the paper feed roller 3 is set so that the pressing force is a pressing force that keeps the upper limit of the appropriate range or less.

  Here, when a recording paper P having a large size and a low density is used, as indicated by a line segment LC, as the stacking thickness of the recording paper P increases, The pressing force increases as compared with the case where the recording paper P having a large size indicated by the line segment LA is used. Similarly, when using a recording paper P having a small size and a low density, as indicated by a line segment LD in FIG. The pressing force increases as compared with the case where the recording paper P having a small size indicated by the line segment LB is used. Therefore, when the recording paper P having a low density is used, the pressing force may exceed the appropriate range as the stacked thickness of the recording paper P increases. In particular, when the recording paper P having a small size and having a low density shown by the line segment LD is used, the tendency that the pressing force exceeds the appropriate range appears more remarkably.

  Therefore, when the recording paper P having the same size and low density is used, as shown in FIG. 4B, the pressing force adjusting block 20 is set at the second position described above and the paper is fed. The recording paper P loaded on the sheet receiving plate 2 is fed to the paper feed roller 3 so that the relationship between the pressing force on the roller 3 and the thickness (bulk) of the recording paper P is as shown in FIG. A pressing force to be pressed is set. That is, in the printing apparatus, when the recording paper P having a large size and low density is used, as shown by the line segment LE in FIG. 7, the line segment LC shown in FIG. Is set so that the recording paper P stacked on the sheet receiving plate 2 is pressed against the paper feed roller 3 so as to be translated downward. Further, in the printing apparatus, when a recording paper P having a small size and a low density is used, as shown by a line segment LF in FIG. The pressing force with which the recording paper P stacked on the sheet receiving plate 2 is pressed against the paper feed roller 3 is set so that the line segment LD is translated downward.

  As described above, in the printing apparatus, the pressing force is changed by switching the position of the pressing force adjusting block 20 according to the density of the recording paper P, as shown in FIG. Therefore, as shown in FIG. 7B, settings suitable for the recording paper P having a low density can be performed.

  In the printing apparatus, regardless of the recording paper size and / or the adjustment position of the pressing force adjusting block 20, the recording paper P is fed even when the number of the recording paper P set is one. The pressing force with which the recording paper P stacked on the sheet receiving plate 2 is pressed against the paper feeding roller 3 is set so that the urging force is applied to the roller 3. The left end of the horizontal axis in FIGS. 7A and 7B indicates the pressing force of the sheet receiving plate 2 against the sheet feeding roller 3 when the number of recording sheets P is set to one or zero.

  As described above, in the printing apparatus shown as the first embodiment of the present invention, the pressing force of the sheet receiving plate 2 is applied to the paper side guide 14 whose position needs to be changed according to the size of the recording paper P. The tension coil spring 18 is attached to generate a tension, and the extension amount of the tension coil spring 18 is changed so that the tension of the tension coil spring 18 automatically becomes an appropriate value according to the operation of changing the size of the recording paper P. Can be made. Therefore, in this printing apparatus, it is possible to change the optimum pressing force for the sheet feeding operation from one large recording sheet to a small recording sheet by one type of tension coil spring 18, while having a simple and inexpensive configuration. Stable paper feeding performance can be realized.

  Further, in this printing apparatus, even if the tension of the tension coil spring 18 that has been set deviates from an appropriate value due to the difference in density and bulk of the recording paper P, the pressing force adjusting block 20 described above is used. By moving to the position 2, the deviation from the optimum value of the pressing force of the recording paper P against the paper feed roller 3 can be compensated.

  Further, the pressing force adjusting block 20 uses the same tension coil spring 18 that is used in common with the means for changing the pressing force, and applies the pressing force to each recording paper size regardless of the position of the paper side guide 14. Since it is configured to be adjustable, this printing apparatus can perform a stable paper feeding operation without complicating the structure.

  Furthermore, in this printing apparatus, since the operation of the pressing force adjusting block 20 can be performed on the paper feed cassette 1 side, the operator removes the paper feed cassette 1 from the printing apparatus main body. It can be easily operated.

  Next, a printing apparatus shown as the second embodiment will be described.

  The printing apparatus shown as the second embodiment, like the printing apparatus shown as the first embodiment, is a surface portion of a paper feed cassette where an operator can touch a movable member such as a tension coil spring. The structure of the paper feeding cassette is simplified by mounting in the printing apparatus, which is a paper feeding cassette mounting guide portion in the printing apparatus. Therefore, in the description of the second embodiment, the same components as those in the description of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 8 is a perspective view of a main part of the paper feed cassette 101 used in the paper feed device in the printing apparatus shown as the second embodiment and the paper feed cassette mounting portion of the main body of the printing apparatus. The paper feed cassette 101 can be attached and detached by sliding it in the directions of arrows C and C ′ in FIG. The sheet feeding cassette 101 is provided with a sheet receiving plate 112 which is a stacking plate on which a plurality of recording sheets P are stacked in a box-shaped cassette case 111. The sheet receive plate 112 can be rotated with respect to a support shaft protruding from the inner surface of the cassette case 111 by two rotation support points 113 (one is not shown) provided coaxially at one end thereof. Is pivotally supported. The sheet receiving plate 112 is a central portion at the other end opposite to the rotation fulcrum 113, and is attached to the sheet feeding roller 3 of the printing apparatus when the sheet feeding cassette 101 is mounted at a predetermined position of the printing apparatus main body. A friction separating piece 114 made of rubber, cork, or the like is fixed to the contact position.

  Further, on the bottom surface of the cassette case 111, a pair of left and right paper side guides 115 (one portion is shown) is a regulating member configured to be slidable in the direction of arrow D in the figure along a slide groove (not shown). Not). These sheet side guides 115 are supported by an operation mechanism (not shown) such as a rack-pinion mechanism so as to be slidable symmetrically with respect to a printing reference position of the printing apparatus such as a center line in the feeding direction of the recording sheet P. In addition, it is configured to be fixed at a predetermined position according to the size of the recording paper P by a holding means (not shown).

  On the other hand, a pair of left and right link levers 116 (one portion is not shown) is provided in the guide portion that is slid when the paper feed cassette 101 is mounted on the printing apparatus main body side. These link levers 116 are pivotally supported by a guide portion in the printing apparatus main body via a support shaft 117. When the paper feed cassette 101 is mounted on the printing apparatus main body, one end of the link lever 116 is provided. A post 118 formed on the portion 116a acts to urge the other end side surface portion 112a of the sheet receive plate 112 from its lower surface toward the paper feed roller 3 (upward). The other end 116b of the link lever 116 is engaged with one end 119a of a pair of left and right tension coil springs 119 (one portion is not shown) as an urging means, and the other end of the tension coil spring 119 is engaged. The portion 119b is engaged with a pair of left and right guide blocks 120 (one portion is not shown) that is slidably supported by a guide portion on the printing apparatus main body side. This guide block 120 is engaged with a pair of left and right protrusions formed on the side surface of the cassette case 111 of the paper feed cassette 101, and the direction of arrow C in FIG. Acting to extend the tension coil spring 119. As shown in FIG. 9, the protrusions are one end portions of a pair of left and right pressing levers 121 (one portion is not shown) that is pivotally supported with respect to a support shaft formed on the bottom surface of the cassette case 111. 121a is formed, and is engaged with the guide block 120 by projecting to the outside of the side surface of the cassette case 111 from a pair of left and right openings 122 (one is not shown) formed on the side surface of the cassette case 111. Yes.

  The other end 121 b of the pressing lever 121 is in contact with the outer surface of the paper side guide 115, and the position of one end (projection) 121 a of the pressing lever 121 is fed according to the position of the paper side guide 115. The cassette 101 is configured to move in the front-rear direction. That is, when the paper side guide 115 is fixed to the outside in order to set a large size recording paper P, the protrusion 121a moves to the rear of the paper feed cassette 101, while the small size recording paper P is moved. When set, it moves to the front of the paper feed cassette 101. Accordingly, the pressing lever 121 is configured as a pressing force changing unit that changes the pressing force of the recording sheet P against the sheet feeding roller 3 by the tension coil spring 119 according to the position of the sheet side guide 115.

  Further, as shown in FIG. 9, a pair of left and right pressing force adjusting eccentric cams 123 serving as pressing force adjusting means are provided at the other end portion 121b of the pressing lever 121 at the portion in contact with the outer surface of the paper side guide 115. (One part is not shown) is included, and the cam surface of the eccentric cam 123 is configured to abut against the outer surface of the paper side guide 115. As shown in FIG. 10A, the eccentric cam 123 has a first position where the cam surface protrudes from the other end 121b of the pressing lever 121, and the other cam surface as shown in FIG. Of the second position that does not protrude from the end portion 121b, the pressure lever 121 is integrally locked at any position and supported so that the position can be maintained. The position of the cam surface of the eccentric cam 123 can be changed by the operator by rotating the slot 124 of the eccentric cam 123 shown in FIG. 9 using a predetermined tool or coin. it can. In addition, the broken line part in FIG.10 (b) has shown the case where the eccentric cam 123 is supported by the 1st position shown to Fig.10 (a).

  In such a printing apparatus, the position of the eccentric cam 123 is normally locked to the above-described first position, so that the recording paper P having a standard density is suitable for the paper feed roller 3. The tension of the tension coil spring 119 is set so as to be urged by the pressing force.

  In a printing apparatus in which such a paper feeding cassette 101 is mounted, when recording paper P is supplied to the printing apparatus, a plurality of recording papers P are supplied to the sheet receiving plate 112 in the paper feeding cassette 101. The paper side guide 115 is loaded in the direction of the arrow D in FIG. 8 according to the width of the loaded recording paper P and fixed by a holding means (not shown).

  In the printing apparatus, when the paper feeding cassette 101 is mounted on the main body of the printing apparatus by sliding it in the direction of arrow C in FIG. 8, the protrusion of the pressing lever 121 is operated immediately before the mounting is completed. The guide block 120 is pushed by the protrusion 121a of the pressing lever 121 by the amount by which the sheet feeding cassette 101 is pushed to the mounting position after the 121a abuts the guide block 120 of the guide portion in the printing apparatus main body, and the pulling coil The spring 119 is extended. In the printing apparatus, the other end portion 116 b of the link lever 116 is urged by the tension when the tension coil spring 119 is extended, and the post 118 formed on the one end portion 116 a of the link lever 116 is connected to the sheet receiving plate 112. The other end portion side surface portion 112a is urged upward, and the leading end portion of the stacked recording paper P acts to abut against the paper feed roller 3 in the printer main body.

  In the printing apparatus, when changing the size of the recording paper P, the paper cassette 101 is removed from the main body of the printing apparatus, and then the holding means (not shown) of the paper side guide 115 is released. By sliding in the direction of the middle arrow D, the paper side guide 115 is fixed again at a position suitable for a predetermined paper size. At this time, the other end 121 b of the pressing lever 121 that is in contact with the outer side surface of the paper side guide 115 also rotates with the movement of the paper side guide 115, and from the side surface of the cassette case 111 that engages with the guide block 120. Since the protruding protrusion 121a moves in the front-rear direction, the tension of the tension coil spring 119 changes according to the position where the paper side guide 115 is fixed. That is, in the printing apparatus, when the recording paper P having a large paper width is set, as shown in FIG. 11, the protruding portion 121a protruding from the side surface of the cassette case 111 is present at the rear, and the tension coil spring 119 When the recording paper P having a small paper width is set while acting to increase the tension, the paper side guide 115 is positioned inside the paper width direction as shown in FIG. The portion 121a exists in the front, and acts to weaken the tension of the tension coil spring 119.

  Further, in the printing apparatus, when the recording paper P having the same size and having a low density and a large bulk is used, the extension amount of the tension coil spring 119 is larger than when the normal recording paper P is set. And a large tension acts, and the pressing force for pressing the recording paper P against the paper feed roller 3 may deviate from an appropriate value. In such a case, in the printing apparatus, the operator rotates the eccentric cam 123 so as to be locked at the above-described second position, thereby reducing the rotation angle of the pressing lever 121 and recording paper P. Therefore, the tension of the tension coil spring 119 can be reduced so that the sheet feeding roller 3 is urged with an appropriate pressing force.

  In the printing apparatus, the recording paper P loaded on the sheet receiving plate 112 is placed on the paper feed roller 3 by appropriately setting the position of the protrusion 121a and the tension of the tension coil spring 119. The pressing force to be pressed is set to an appropriate range for performing a normal paper feeding operation according to the size of the recording paper P and the loading amount of the recording paper P.

  As described above, in the printing apparatus shown as the second embodiment of the present invention, in the same manner as the printing apparatus shown as the first embodiment, the automatic operation is performed according to the operation for changing the size of the recording paper P. Therefore, the extension amount of the tension coil spring 119 can be changed so that the tension of the tension coil spring 119 becomes an appropriate value. Therefore, in this printing apparatus, it is possible to change the optimum pressing force for the paper feeding operation from one large recording paper to a small recording paper by one type of tension coil spring 119, while having a simple and inexpensive configuration. Stable paper feeding performance can be realized.

  Here, in the printing apparatus shown as the first embodiment, the movable member such as the tension coil spring is mounted on the surface portion of the paper feed cassette that can be touched by the operator. In the printing apparatus shown as the embodiment, the structure of the paper feed cassette 101 can be simplified by mounting in the printing apparatus, which is a paper feed cassette mounting guide portion of the printing apparatus.

  Further, in this printing apparatus, even if the set tension of the tension coil spring 119 deviates from an appropriate value due to the difference in density and bulk of the recording paper P, the eccentric cam 123 is used by using a tool, a coin or the like. Is moved to the above-described second position, the deviation from the optimum value of the pressing force of the recording paper P against the paper feed roller 3 can be compensated.

  Further, the eccentric cam 123 can adjust the pressing force for each recording paper size regardless of the position of the paper side guide 115 while using the same tension coil spring 119 that is used in common with the means for changing the pressing force. Because of this configuration, this printing apparatus can perform a stable paper feeding operation without complicating the structure.

  Furthermore, in this printing apparatus, the eccentric cam 123 can be operated on the side of the paper feed cassette 101, and a tension coil spring 119 or the like is attached to the surface portion of the paper feed cassette 101 that can be touched by the operator. Since the movable member is not mounted, the operator can operate more easily than the printing apparatus shown as the first embodiment when performing the operation of taking out the paper feed cassette 1 from the main body of the printing apparatus. It is possible.

  The present invention is not limited to the embodiment described above. For example, in the first embodiment described above, the tension of the tension coil spring 18 is weakened in order to correspond to the normally used first position and the recording paper P having a low density as the position of the pressing force adjusting block 20. However, according to the present invention, the recording paper P having a high density has a lower position than the normal position, that is, the tension of the tension coil spring 18. It is also possible to set a third position that acts stronger than usual. Thereby, in the printing apparatus, the optimum value of the pressing force of the recording paper P against the paper feed roller 3 can be obtained more easily.

  Similarly, in the second embodiment described above, as the position of the eccentric cam 123, the first position that is normally used and the tension of the tension coil spring 119 act to weaken the recording paper P to have a low density. However, according to the present invention, the position where the recording paper P with high density protrudes further than the normal position, that is, the tension of the tension coil spring 119 is higher than normal. It is also possible to set a third position that acts more strongly. In the present invention, the cam profile of the eccentric cam 123 may be formed in a curved shape so that the engagement position of the eccentric cam 123 can be selected continuously. Accordingly, in the printing apparatus, it is possible to finely adjust the pressing force of the recording paper P against the paper feed roller 3 with fine accuracy, and the optimum value of the pressing force can be obtained more easily.

  Furthermore, in the first and second embodiments described above, the recording paper P is pressed against the paper feed roller 3 that feeds the recording paper P stacked on the sheet receiving plates 2 and 112 one by one, and biased. The tension coil springs 18 and 119 have been described as the biasing means. However, the present invention realizes a similar biasing function in addition to an elastic body such as the tension coil springs 18 and 119 as the biasing means. Anything can be applied.

  Furthermore, in the first and second embodiments described above, the paper feeding cassettes 1 and 101 that can be attached to and detached from the main body of the printing apparatus have been described as the paper feeding apparatus used in the printing apparatus such as a printer. However, the present invention can also be applied to a paper pressing portion of a paper feed tray that is formed integrally with the printing apparatus main body. The present invention can also be applied to a paper feeding device of various image forming apparatuses that have at least an image forming unit such as a copying machine other than a printer and a facsimile machine, and further, a scanner. The present invention can also be applied to a hopper device that sets a recording sheet as a read document in a reading device that reads document information such as a device or an OCR (Optical Character Reader) device.

  Thus, it goes without saying that the present invention can be modified as appropriate without departing from the spirit of the present invention.

1 is a cross-sectional view illustrating a schematic configuration of a printing apparatus illustrated as a first embodiment of the present invention. FIG. 3 is a perspective view of a main part for explaining a configuration of a paper feeding cassette and a paper feeding cassette mounting portion of the printing apparatus main body in the printing apparatus. FIG. 6 is a perspective view of a main part for explaining a state in which a pressing force adjusting block is attached to a paper side guide in the printing apparatus. FIG. 4 is a side view of a main part for explaining a state in which a pressing force adjusting block is supported at a first position in the printing apparatus. It is a principal part side view explaining a mode that the block for pressing force adjustment in the printing apparatus is supported by the 2nd position. FIG. 6 is a side view of a main part for explaining a state where a paper feed cassette is not attached to the printing apparatus main body. FIG. 4 is a side view of a main part for explaining a state where a paper feed cassette is mounted on the printing apparatus main body. FIG. 6 is a diagram for explaining setting of a pressing force with which a recording sheet stacked on a sheet receiving plate is pressed against a sheet feeding roller in the printing apparatus, and a pressing force adjusting block is set at a first position. FIG. 6 is a diagram for explaining a relationship between a pressing force applied to a sheet feeding roller and a stacked thickness (bulk) of recording paper in a case where the recording paper is pressed. FIG. 6 is a diagram for explaining setting of a pressing force with which a recording sheet loaded on a sheet receiving plate is pressed against a sheet feeding roller in the printing apparatus, and a pressing force adjustment block is set at a second position. FIG. 6 is a diagram for explaining a relationship between a pressing force applied to a sheet feeding roller and a stacked thickness (bulk) of recording paper in a case where the recording paper is pressed. FIG. 10 is a perspective view illustrating a main part of a sheet feeding cassette and a sheet feeding cassette mounting portion of the printing apparatus main body in the printing apparatus according to the second embodiment of the present invention. It is a principal part perspective view explaining the structure of the press lever and eccentric cam in the printing apparatus. It is a principal part side view explaining a mode that the eccentric cam in the printing apparatus is supported by the 1st position. It is a principal part side view explaining a mode that the eccentric cam in the printing apparatus is supported by the 2nd position. FIG. 3 is a plan view of a main part for explaining a state in which a recording sheet having a large sheet width is set in the printing apparatus. FIG. 4 is a plan view of a principal part for explaining a state where a recording sheet having a small sheet width is set in the printing apparatus.

DESCRIPTION OF SYMBOLS 1,101 Paper feed cassette 2,112 Sheet receive plate 2a Side part 3 Paper feed roller 4 Conveyance roller 5 Image formation part 6 Fixing part 11,111 Cassette case 12,113 Rotation fulcrum 13,114 Friction separation piece 14,115 Paper Side guides 14a, 122 Closed portion 14b Oval hole for block movement 15 Sliding block 16a, 16b Sliding groove 17 Groove 18, 119 Tension coil spring 19, 117 Support shaft 20 Pressing pressure adjusting block 21, 121 Pressing lever 22, 121a Projection 116 Link lever 118 Post 120 Guide block 123 Eccentric cam 124 Slot P Recording paper

Claims (10)

A loading plate for loading a plurality of predetermined recording sheets;
A regulating member that is movable in accordance with the width of the recording paper and regulates the width direction of the recording paper;
A plurality of urging means respectively provided at both ends in the width direction of the recording medium and urging the stacking plate with respect to a paper feed roller for feeding out the recording sheets stacked on the stacking plate;
A sliding member slidably supported with respect to the loading plate;
A pressing force changing unit that includes a lever member that is rotatably supported with respect to the regulating member, and that changes the pressing force of the stacking plate against the paper feeding roller by the biasing unit according to the position of the regulating member. When,
A pressing force adjusting means for adjusting the pressing force by the pressing force changing means,
One end of the urging means is locked to the lever member, and the other end is locked to the sliding member. The pressing force adjusting means is
Provided between the regulating member and the biasing means;
The sheet feeding device according to claim 1, wherein the pressing force can be adjusted for each recording sheet size regardless of the position of the regulating member. The biasing means is a predetermined elastic body provided in a paper feed cassette as the paper feed device configured to be detachable from the apparatus main body,
The sheet feeding device according to claim 1, wherein the pressing force adjusting unit is provided in the sheet feeding cassette. The pressing force adjusting means is
A support portion for supporting the lever member;
The regulating member is
The pressing force adjusting means can be fixed at a fixed position with respect to the stacking plate at either the first fixed position or the second fixed position positioned on the stacking plate side with respect to the first fixed position. The sheet feeding device according to any one of claims 1 to 3, wherein the sheet feeding device is provided. 2. The apparatus main body is an image forming apparatus that forms an image on the recording paper, or a hopper device that sets the recording paper as a reading original in a reading apparatus that reads original information. The sheet feeding device according to claim 4 . In an image forming apparatus that forms an image on a predetermined recording sheet,
An apparatus main body having at least an image forming unit;
A paper feeding device for feeding the recording paper to the device main body,
The paper feeder is
A loading plate for loading a plurality of the recording sheets;
A regulating member that is movable in accordance with the width of the recording paper and regulates the width direction of the recording paper;
A plurality of urging means respectively provided at both ends in the width direction of the recording medium and urging the stacking plate with respect to a paper feed roller for feeding out the recording sheets stacked on the stacking plate;
A sliding member slidably supported with respect to the loading plate;
A pressing force changing unit that includes a lever member that is rotatably supported with respect to the regulating member, and that changes the pressing force of the stacking plate against the paper feeding roller by the biasing unit according to the position of the regulating member. When,
A pressing force adjusting means for adjusting the pressing force by the pressing force changing means,
One end portion of the urging means is locked to the lever member, and the other end portion is locked to the sliding member. The pressing force adjusting means is
Provided between the regulating member and the biasing means;
The image forming apparatus according to claim 6 , wherein the pressing force can be adjusted for each recording paper size regardless of a position of the restricting member. The paper feeding device is a paper feeding cassette configured to be detachable from the device main body,
The biasing means is a predetermined elastic body provided in the paper feed cassette,
The image forming apparatus according to claim 6 , wherein the pressing force adjusting unit is provided in the sheet feeding cassette. The pressing force adjusting means is
A support portion for supporting the lever member;
The regulating member is
The pressing force adjusting means can be fixed at a fixed position with respect to the stacking plate at either the first fixed position or the second fixed position positioned on the stacking plate side with respect to the first fixed position. The image forming apparatus according to claim 6 , wherein the image forming apparatus is provided. In an image forming apparatus having an image forming unit for forming an image on a predetermined recording sheet, and having a sheet feeding device for feeding the recording sheet to an apparatus main body,
The paper feeder is
A loading plate for loading a plurality of the recording sheets;
A regulating member that is movable in accordance with the width of the recording paper and regulates the width direction of the recording paper;
A plurality of urging means respectively provided at both ends in the width direction of the recording medium, for urging the stacking plate with respect to a paper feed roller for feeding out the recording sheets stacked on the stacking plate;
A sliding member slidably supported with respect to the loading plate;
A pressing force changing unit that includes a lever member that is rotatably supported with respect to the regulating member, and that changes the pressing force of the stacking plate against the paper feeding roller by the biasing unit according to the position of the regulating member. When,
A pressing force adjusting means for adjusting the pressing force by the pressing force changing means,
The apparatus main body is
An abutting portion having an inclined surface so that the abutting position of the lever member can move backward for a while toward the central portion of the recording paper in the width direction of the recording paper stacked on the stacking plate; Prepared,
One end portion of the urging means is locked to the lever member, and the other end portion is locked to the sliding member.