JP2014148379A - Recording medium supply device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust force for pressing paper in a wide range.SOLUTION: A recording medium supply device presses a pressing roller 50, which is disposed at one end part of a first rotary arm 51, against the uppermost surface of a sheet-like recording medium. A biasing lever 71 having a biasing roller 72 and a first tension spring 73 are attached to a biasing force adjustment member 60 which may slide. The biasing lever 71 is rotationally biased by the first tension spring 73 to place the biasing roller 72 in contact with the first rotary arm 51. The biasing force adjustment member 60 is slid thereby moving the biasing roller 72 along a longitudinal direction of the first rotary arm 51 to change pressing force of the pressing roller 50.

Description

  The present invention relates to a recording medium supply device that supplies a sheet-like recording medium, and an image forming apparatus including the recording medium supply device.

  As is well known, an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine of these includes a paper feeding device that supplies paper, an OHP film, and the like one by one. In particular, when the paper feeding device is capable of mounting a large amount of paper, air separation is performed by blowing air to the bundled paper loaded in a stacked state on the tray so that the paper (recording medium) is floated and separated from each other. A paper feeder is provided. With this air separating and feeding apparatus, the uppermost sheet is adsorbed by a perforated adsorbing belt having a plurality of air intake ports for sucking air, and the belt is driven to convey the sheet. Examples of conventional air separating and feeding apparatuses include those described in Patent Document 1 (Japanese Patent Laid-Open No. 2001-247229) and Patent Document 2 (Japanese Patent Laid-Open No. 2007-45630).

  FIG. 10 shows a schematic configuration of the air separation sheet feeding device. An air separating and feeding apparatus 301 shown in FIG. 10 includes a paper feed tray 302 on which a plurality of sheets P are mounted, a front blower 303 and a side blower 304 that blow air to the upper front end and the upper side end of the loaded sheets P. , A suction belt 305 for sucking and transporting the loaded paper P one by one is provided. The paper P is aligned on the front tray 306 as a reference surface so that the paper P fits the size of the paper P on the paper feed tray 302.

  In order to supply the paper P by the air separation paper feeding device 301, first, air is blown from the front blower 303 and the side blower 304 toward the bundle of paper P mounted on the paper feed tray 302. By this air, air is sent between the sheets P, and the sheets P are lifted up to the height h of the suction belt 305 while being rolled. Of the floated sheets, the uppermost sheet P1 is attracted to the suction belt 305, and the suction belt 305 rotates in this state, whereby the sheet P1 is conveyed to an image forming unit (not shown) to form an image. Is done.

  By the way, in order to reliably suck and feed a wide variety of paper such as thick paper and thin paper one by one to the suction belt 305 without feeding them, the height h between the suction belt 305 and the uppermost paper P1. It is important to make the adsorption constant and stable. For this reason, the air separating and feeding apparatus of Patent Documents 1 and 2 includes an upper surface position detecting unit that detects the position of the uppermost sheet P1.

  As the upper surface position detecting means, for example, as shown in FIG. 10, a device having a swing member 310 that abuts on the uppermost surface of the sheet bundle and a swing detection sensor 320 that detects the swing of the swing member 310. is there. The attachment position of the swing member 310 is provided in the vicinity of the suction belt 305 so as to keep the target distance h with stable accuracy regardless of the size of the paper.

  In such an apparatus, when the sheet is supplied and the height h of the sheet bundle is lowered, the swinging member 310 is rotated in a direction to be lowered. Then, the swing detection sensor 320 detects the amount of rotation of the swing member 310, and based on the detection signal at that time, the lifting means (not shown) raises the bottom plate of the paper feed tray 302, thereby To the suction belt 305 is controlled to be constant.

  The pressing force of the swing member 310 against the paper P1 is desirably adjusted to increase or decrease according to the type of the paper P1. Pressing thin paper or coated paper (coated paper, art paper, etc.) strongly may damage the paper surface. If there is not enough force to hold the cardboard, the swinging member 310 will lose the stiffness of the cardboard and be accurate. The height h cannot be detected.

  Also, as disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 2011-73864), the swinging member 310 is temporarily separated from the upper surface of the paper every time air is blown onto the paper in order to minimize damage to the paper during conveyance. There is a paper feeding device to be made to do. In such a paper feeding device, when the contact and separation of the roller of the swinging member 310 are repeated at high speed for high-speed paper conveyance, the collision force of the roller with respect to the upper surface of the paper becomes large and roller marks are likely to be attached. In the case of hard cardboard, the occurrence of a collision sound when the roller of the swinging member 310 abuts may be a problem.

  Therefore, for example, as shown in FIG. 11, it is conceivable to increase / decrease the pressing force of the swing member 310 by increasing / decreasing the tension force of the tension spring 333. In the figure, reference numeral 307 denotes a support plate disposed horizontally on the upper portion of the paper feed tray 302, and 311 denotes a rotating arm supported rotatably on the support plate 307. Reference numeral 312 denotes a support shaft of the rotating arm 311, and 313 denotes a pressing roller that is rotatably disposed at the tip of the rotating arm 311.

  321 is a photosensor, 322 is a filler, and 330 is an urging lever supported rotatably on a support plate 307. Reference numeral 331 denotes a support shaft of the urging lever 330, and 332 denotes an urging roller rotatably disposed at the tip of the urging lever 330.

  Reference numeral 333 denotes a tension spring having one end connected to the biasing lever 330, and 334 denotes an operation lever connected to the other end of the tension spring 333 and extending in the direction perpendicular to the paper surface. As shown in FIGS. 12A and 12B, the operation lever 334 extends in a direction transverse to the sheet feeding direction.

  The filler 322 is formed integrally with the rotating arm 311 and moves to the front of the photosensor 321 so as to block the optical axis thereof so that the filler 322 is detected. The photosensor 321 is supported by the support shaft 312 as shown in FIGS. 12A and 12B, and the height of the photosensor 321 is adjusted in the vertical direction around the support shaft 312 by turning the grip 335 at the end of the support shaft 312. Thus, the height h of the paper P when the filler 322 is detected can be set.

  In the sheet feeding device of FIG. 11, the urging roller 332 of the urging lever 330 presses the upper surface of the rotating arm 311 with the force of the tension spring 333. Accordingly, the pressing force of the pressing roller 313 against the paper P1 can be increased or decreased by adjusting the biasing force of the tension spring 333 by adjusting the movement of the operation lever 334 in the horizontal direction in FIG.

  As shown in FIG. 11, when the operation lever 334 is moved left and right to increase or decrease the tension force of the tension spring 333, the width of the tension force that can be adjusted depends on mechanical characteristics such as an allowable elongation amount and an allowable load of the tension spring 333. It depends directly. For this reason, since the adjustment range of the tensile force is naturally limited, it is difficult to optimize the pressing force against a wide variety of sheets. Further, if the adjustment range of the tension force of the tension spring 333 is to be increased, the operation range of the operation lever 334 must be set to be large. Then, a wide free space is required around the operation lever 334, and it becomes difficult to make the apparatus compact.

  On the other hand, when the adjustment range of the tensile force of the tension spring 333 is widened, as in the paper feeding device of Patent Document 3 (Japanese Patent Application Laid-Open No. 2011-73864), in order to move the swing member 310 up and down with a solenoid, the solenoid Needs to correspond to the maximum pressing force of the pressing roller 313. There are two types of solenoids, a type in which the pressing roller 313 is separated from the sheet by energization (energization-separation type) and a type in which the pressing roller 313 is brought into contact with the sheet by energization (energization-contact type). The paper feeding device disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 2011-73864) is an energization-separation type. The type of paper feeding device is determined in consideration of the productivity of the device (CPM = Copies Per Minute) and power consumption. Will be decided.

  The energization-contact type includes a pressing release spring that rotates the swinging member 310 upward against the tension spring 333 of FIG. 11 when the solenoid is turned off, and the solenoid applies the biasing force of the pressing release spring when the solenoid is turned on. The power to cancel is necessary. Further, the energization-separation type solenoid is turned on to rotate the swing member 310 upward against the tension spring 333. Therefore, in any type, when the urging force of the tension spring 333 is increased, a large solenoid is required.

  However, when the biasing force of the tension spring 333 is set to be small because no thick paper or the like is used, a small solenoid is sufficient for both types. However, in the energization-contact type, in order to suppress the number of parts, the swing member 310 is rotated upward by only one kind of pressing release spring in most models. For this reason, even when the biasing force of the tension spring 333 is set to a small value, it is necessary to use a pressing release spring having a strong biasing force, and the solenoid must be a large solenoid having a suction force corresponding to the strong biasing force. It was. For this reason, problems such as an increase in the size of solenoids and related devices, an increase in power consumption, and a cost increase have occurred.

  The present invention has been made in view of the above problems. A first object of the present invention is to make it possible to widely adjust the pressing force against a sheet. As a result, the paper height is reliably detected regardless of the paper type (recording medium type), and the paper is reliably conveyed, and at the same time, the damage, scratches, and collision noise are detected. To prevent. The second object of the present invention is to enable the biasing force of the pressing release spring to be increased / decreased in correspondence with the increase / decrease of the pressing force against the paper in the energization-contact type device, and to set the pressing force against the paper to a small force. The object is to enable the swinging member 310 to move up and down by canceling the urging force of the pressing release spring with a small solenoid without replacing the pressing release spring.

  In order to solve the above-described problem, the recording medium supply device according to the present invention has an uppermost surface of a sheet-like recording medium in which a pressing member disposed at one end of the first rotating arm is mounted in a stacked state on the recording medium mounting portion. In the recording medium supply apparatus that is pressed against the first rotation arm, the first biasing unit that applies a pressing force to the pressing member by biasing the first rotation arm in the rotation direction is provided on the first rotation arm. It is arranged to be movable along the longitudinal direction, and the pressing force of the pressing member can be changed by moving the first urging means.

  In the present invention, since the first urging means of the first rotating arm is movable along the longitudinal direction of the first rotating arm, the first urging means can be moved by moving the first urging means. Regardless of the mechanical limit value, the pressing force of the pressing member can be widely adjusted. Therefore, when using a recording medium that is easily damaged, it is possible to prevent the recording medium from being damaged by reducing the pressing force, and when using a hard recording medium, the impact sound is reduced by reducing the pressing force. Can be prevented. In addition, when using a stiff recording medium, the pressing force is increased so as not to lose the strength of the stiffness, thereby enabling accurate detection of the top surface position of the recording medium and reliable transport of the recording medium. It becomes possible.

1 is an external view showing an embodiment of an image forming apparatus provided with a sheet feeding device of the present invention. 1 is a schematic configuration diagram of an image forming apparatus main body. 1 is a schematic configuration diagram of an entire sheet feeding device. It is a perspective view which shows the internal structure of a paper feed tray. It is the perspective view which looked at the adsorption belt unit from the lower side. It is a perspective view of a pressing force variable mechanism. It is a perspective view of the pressing force variable mechanism shown with the bracket removed. FIG. 6B is a perspective view of the pressing force variable mechanism as seen from a direction different from FIG. 6A. It is a side view of a pressing force variable mechanism. FIG. 6 is a side view of a friction separating roller type paper feeding device according to a modified embodiment of the present invention. It is a schematic block diagram of the conventional air separation paper feeder. It is a side view of the pressing force variable mechanism examined in the development stage of the present invention. It is the perspective view which looked at the pressing force variable mechanism of the development stage from the top, Comprising: It is the perspective view of the state which increased the pressing force. It is the perspective view which looked at the pressing force variable mechanism of the development stage from the top, Comprising: It is the perspective view of the state which made the pressing force small.

  Hereinafter, an embodiment of a recording medium supply apparatus of the present invention will be described with reference to the accompanying drawings. In each drawing explaining this embodiment, constituent elements such as members and components having the same function or shape are given the same reference numerals as much as possible, and the explanation will be given after once explained. Omitted.

(Image forming device)
FIG. 1 is an external view showing an embodiment of an image forming apparatus provided with a paper feeding device (recording medium supply device) according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 1 is connected to an image forming apparatus main body 2 and one side surface of the image forming apparatus main body 2, and is a sheet as a sheet-like recording medium with respect to the image forming apparatus main body 2. And a paper feeding device 3 for supplying the paper.

  FIG. 2 is a schematic configuration diagram of the image forming apparatus main body. As shown in FIG. 2, the image forming apparatus main body 2 includes four process units 4Y, 4C, 4M, and 4Bk. Each process unit 4Y, 4C, 4M, 4Bk is configured to be detachable from the image forming apparatus main body 2. The process units 4Y, 4C, 4M, and 4Bk have the same configuration except that toners of different colors of yellow, cyan, magenta, and black corresponding to the color separation components of the color image are accommodated.

  Specifically, each of the process units 4Y, 4C, 4M, and 4Bk includes a photosensitive member 5 as an electrostatic latent image carrier and a charging roller 6 as a charging unit that charges the surface of the photosensitive member 5. Further, a developing device 7 as a developing unit for forming a toner image on the surface of the photoconductor 5 and a cleaning blade 8 as a cleaning unit for cleaning the surface of the photoconductor 5 are provided.

  In FIG. 1, an exposure device 9 as exposure means is disposed above each process unit 4Y, 4C, 4M, 4Bk. The exposure device 9 is configured to irradiate the photoconductor 5 of each process unit 4Y, 4C, 4M, 4Bk with laser light.

  On the other hand, a transfer device 10 is disposed below the process units 4Y, 4C, 4M, and 4Bk. The transfer device 10 includes an intermediate transfer belt 15 formed of an endless belt that is stretched around a plurality of rollers 11 to 14. The intermediate transfer belt 15 is configured to be able to run in the direction indicated by the arrow in the drawing when one of the rollers 11 to 14 rotates as a driving roller.

  Four primary transfer rollers 16 as primary transfer means are disposed at positions facing the four photoconductors 5. Each primary transfer roller 16 pressurizes the inner peripheral surface of the intermediate transfer belt 15 at each position, and a primary transfer nip is formed at a location where the pressed portion of the intermediate transfer belt 15 and each photoconductor 5 are in contact with each other. Has been. In addition, a secondary transfer roller 17 as a secondary transfer unit is disposed at a position facing one roller 14 around which the intermediate transfer belt 15 is wound. The secondary transfer roller 17 pressurizes the outer peripheral surface of the intermediate transfer belt 15, and a secondary transfer nip is formed at a location where the secondary transfer roller 17 and the intermediate transfer belt 15 come into contact with each other.

  In the image forming apparatus main body 2, a conveyance path R is provided for guiding the paper supplied from the paper feeding device 3 to a paper discharge tray 18 provided outside the apparatus through a secondary transfer nip. In the transport path R, a timing roller pair 19 is disposed upstream of the position of the secondary transfer roller 17 in the paper transport direction. A fixing device 20 is disposed downstream of the position of the secondary transfer roller 17 in the sheet conveyance direction. Further, a paper discharge roller pair 21 is disposed downstream of the fixing device 20 in the paper conveyance direction.

  The fixing device 20 includes a heating roller 20a having a heating source therein, and a pressure roller 20b that pressurizes the heating roller 20a. The heating roller 20a and the pressure roller 20b are in contact with each other at a predetermined pressure, and a fixing nip is formed at the contact portion.

(Basic operation of image forming apparatus)
The basic operation of the image forming apparatus will be described below with reference to FIG.
The photoconductors 5 of the process units 4Y, 4C, 4M, and 4Bk are rotationally driven counterclockwise in the drawing, and the surface of each photoconductor 5 is uniformly charged to a predetermined polarity by the charging roller 6. Based on image information of a document read by a reading device (not shown), the surface of each photoconductor 5 charged from the exposure device 9 is irradiated with laser light, and an electrostatic latent image is formed on the surface of each photoconductor 5. Is done. At this time, the image information to be exposed on each photoconductor 5 is single-color image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. As the toner is supplied to the electrostatic latent image formed on the photosensitive member 5 by each developing device 7 in this manner, the electrostatic latent image is visualized as a toner image.

  One of the rollers that pressurizes the intermediate transfer belt 15 is driven to rotate, causing the intermediate transfer belt 15 to run in the direction of the arrow in the figure. In addition, a constant voltage having a polarity opposite to the charging polarity of toner or a voltage controlled by a constant current is applied to each primary transfer roller 16, so that the primary transfer nip between each primary transfer roller 16 and each photoconductor 5. A transfer electric field is formed. Then, the toner images of the respective colors formed on the respective photoconductors 5 are sequentially superimposed and transferred onto the intermediate transfer belt 15 by the transfer electric field formed in the primary transfer nip.

  In this way, the intermediate transfer belt 15 carries a full-color toner image on its surface. Further, the toner that could not be transferred to the intermediate transfer belt 15 remains on the surface of each photoconductor 5 after the transfer. The toner remaining on the photoreceptor 5 is removed by the cleaning blade 8.

  The sheet is unloaded from the sheet feeding device 3 shown in FIG. 1, and the unloaded sheet is timed by the timing roller pair 19 to perform secondary transfer between the secondary transfer roller 17 and the intermediate transfer belt 15. Sent to the nip. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 15 is applied to the secondary transfer roller 17, and a transfer electric field is formed in the secondary transfer nip. Then, the toner image on the intermediate transfer belt 15 is collectively transferred onto the sheet by the transfer electric field formed in the secondary transfer nip.

  The sheet on which the toner image is transferred is conveyed to the fixing device 20. In the fixing device 20, the paper is sandwiched between the heating roller 20a and the pressure roller 20b and heated and pressurized, and the toner image is fixed on the paper. Thereafter, the sheet is discharged to the discharge tray 18 by the pair of discharge rollers 21.

  The above description is an image forming operation when a full-color image is formed on a sheet. However, any one of the four process units 4Y, 4C, 4M, and 4Bk is used to form a monochromatic image, or two or three process units are used to form a two-color or three-color image. It is also possible to do.

(Paper feeder)
Next, based on FIGS. 3-8, the structure of the paper feeder which concerns on embodiment of the recording medium supply apparatus of this invention is demonstrated. FIG. 3 is a schematic configuration diagram of the entire sheet feeding device 3. The sheet feeding device 3 shown in FIG. 1 has a sheet feeding tray 32 as a recording medium mounting section on which a plurality of sheets P as sheet-like recording media can be mounted in a stacked state, and suction as a conveying means for conveying the sheets P. A belt 33 is provided.

  An upper surface position detecting device 34 as an upper surface position detecting means for detecting the upper surface position of the loaded sheet bundle is disposed above the paper feed tray 32. Based on the detection result of the upper surface position detection device 34, the height of the upper surface of the sheet bundle is changed by a lifting means (not shown). A front blower 35 and a side blower 36 are disposed on the front side and the left and right sides of the paper feed tray 32 as air discharge means for blowing air onto the loaded paper bundle and causing the uppermost sheet to float.

  The front blower 35 has a blower fan 35a and an air duct 35b, and discharges a horizontal separation air A1 and a slanting upward floating air A2 from the air duct 35b. The side blower 36 feeds air from the left and right sides to the lower side of the paper P1.

  A pair of conveyance rollers 37 is disposed downstream of the suction belt 33 in the sheet conveyance direction. A paper detection sensor 38 is disposed further downstream of the conveyance roller pair 37.

  The paper feed tray 32 is configured to be able to be taken out by opening the front door (not shown) of the paper feed device 3 in FIG. The paper can be exchanged or supplemented to the paper feed tray 32 taken out from the paper feed device 3. The paper P that can be mounted on the paper feed tray 32 includes thick paper, postcard, envelope, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like. The paper feeding device according to the embodiment of the present invention is configured to be able to supply an OHP sheet or an OHP film as a sheet-like recording medium other than paper.

  FIG. 4 is a perspective view showing an internal structure of the paper feed tray 32 as a recording medium mounting portion. The paper feed tray 32 has a box shape with the top opened, and a suction belt unit having a suction belt 33 and the like is attached to the top of the paper feed tray 32. The paper feed tray 32 includes a bottom plate 32a and a front fence 32b that positions the front end in the transport direction of a sheet bundle mounted on the bottom plate 32a. Further, it has a pair of side fences 32c for positioning both ends in the width direction (direction orthogonal to the transport direction) of the sheet bundle and an end fence 32d for positioning the rear end in the transport direction of the sheet bundle. The replacement or replenishment of paper is performed from above the paper feed tray 32.

  One front air discharge port 35c is provided in the vicinity of the upper portion of the front fence 32b, and a pair of side air discharge ports 36a and 36a are provided in the upper portions of the two side fences 32c. The discharge ports 35c and 36a are connected to blowers (front blower 35 and side blower 36) disposed in each fence via a duct (not shown). The air discharged from the discharge ports 35 c and 36 a is blown onto the upper layer of the sheet bundle mounted on the paper feed tray 32.

  A suction belt unit 41 having a suction belt 33 and the like shown in FIG. 5 is attached to the upper portion of the paper feed tray 32 on the front fence 32b side so as to cross the upper side of the paper feed tray 32 in the width direction. The suction belt 33 is stretched between the driving roller 42 and the driven roller 43 with a predetermined tension applied. When the drive motor 44 is connected to the drive roller 42 and the drive motor 44 is driven at a preset paper feed timing, the drive roller 42 is driven to rotate, and the suction belt 33 rotates in the direction of the arrow. .

  A box-shaped suction chamber 45 having a downward opening (upward in FIG. 5) is provided in a region between the driving roller 42 and the driven roller 43 and surrounded by the suction belt 33. The suction chamber 45 is connected to a suction blower (not shown) via a suction duct 46. When the suction blower is driven and air is sucked from the suction chamber 45 through the suction duct 46, the inside of the suction chamber 45 becomes negative pressure. As a result, air is sucked from a plurality of suction ports 33a formed in the suction belt 33, and the sheet is sucked to the lower surface of the suction belt 33 by the sucked air.

  An upper surface position detecting device 34 is disposed on the upstream side of the suction belt 33. The upper surface position detection device 34 includes a first rotation arm 51 having a pressing roller 50 as a pressing member, and a photosensor 52 that detects the rotation position of the first rotation arm 51. Of course, the photo sensor 52 can be replaced with other sensors (including contact type and non-contact type) that can detect the rotation position of the first rotation arm 51.

  A rotation shaft 53 is arranged on the side of the driven roller 43 of the suction belt 33 in parallel with the driven roller 43 as shown in FIGS. A first rotating arm 51 is rotatably attached to the rotating shaft 53. The photosensor 52 is fixed to a rotating shaft 53 via a bracket 54.

  The end of the rotation shaft 53 is connected to a grip 335 disposed on the front side of the sheet feeding device 3 as shown in FIGS. 12A and 12B. The position of the photosensor 52 can be lowered or raised by rotating the grip 335 forward or backward by a predetermined amount.

  As shown in FIGS. 6A and 6B, the first rotating arm 51 is formed wide in a direction orthogonal to the paper feeding direction. An arm portion 51 a is formed at the width direction end of the first rotation arm 51 in a direction orthogonal to the rotation shaft 53.

  A pressing roller 50 is rotatably disposed at the tip of the arm portion 51a. In addition, a plate-like first pressed portion 51 b that can contact and separate a pressing portion 81 d of an L-shaped arm 81 to be described later is formed at the opposite end of the first rotating arm 51. The pressing force of the pressing roller 50 can be changed by a pressing force variable mechanism described later.

  In addition, a second pressed portion 51 c extending in a plate shape in parallel with the arm portion 51 a is formed at the intermediate portion in the width direction of the first rotating arm 51. Further, a filler 51d detected by the photosensor 52 is formed between the arm portion 51a and the second pressed portion 51c.

  A support member 58 formed by bending a sheet metal is disposed above the first rotation arm 51 as shown in FIG. 6A. The support member 58 is provided with an urging force adjusting member 60 that constitutes a pressing force variable mechanism. The urging force adjusting member 60 lifts the pressing roller 50 of the first rotating arm 51 against the rotational moment of the first rotating arm 51 by the urging roller 72 described later and the rotating moment by the urging roller 72. It is for adjusting power simultaneously. The urging force adjusting member 60 is arranged to be slidable in the direction of the arrow in FIGS. 6B and 7, and is configured to be able to change the pressing force of the pressing roller 50 by the urging roller 72 by the sliding movement as will be described later. ing.

  As shown in FIG. 7, the biasing force adjusting member 60 is fixed to the support member 58 by a set screw 61 fixed to the support member 58 side through the long hole 60a1. An elongated hole 60a2 having the same shape is formed on the extended line of the elongated hole 60a1, and an emboss 58a formed on the support member 58 side is inserted into the elongated hole 60a2. And the parallel movement of the urging | biasing force adjustment member 60 is ensured by the set screw 61 and the embossing 58a.

  The urging force adjusting member 60 supports the urging lever 71 constituting the first urging means 70 so as to be rotatable. As shown in FIGS. 7 and 8, the urging lever 71 is rotatably supported by a support shaft 62 supported by the urging force adjusting member 60 in the vicinity of the upper end portion thereof. An urging roller 72 is rotatably disposed at the lower end of the urging lever 71, and the urging roller 72 is always in contact with the second pressed portion 51 c of the first rotating arm 51.

  One end of a horizontal first tension spring 73 constituting the first urging means is connected to a spring hooking portion 71 a formed at the upper end of the urging lever 71. The other end of the first tension spring 73 is fixed to the first spring hook 60 b of the biasing force adjusting member 60. As a result, the urging lever 71 is constantly urged to rotate clockwise in FIG. Due to this rotation biasing force, the biasing roller 72 is always in contact with the second pressed portion 51c of the first rotation arm 51 with a predetermined pressure, and biases the first rotation arm 51 in the rotation direction. .

  In this embodiment, the first rotating arm 51 is not urged directly by the first tension spring 73 but is urged indirectly via the urging lever 71 and the urging roller 72. This is because the urging force of the first tension spring 73 is greatly reduced by the lever ratio of the urging lever 71 with the support shaft 62 as the center, so that the first tension spring 73 having a relatively large spring constant can be used. Because. Further, by increasing the spring constant of the first tension spring 73, it is possible to reduce the spring space (the number of turns and the spring diameter) and the manufacturing cost.

  The first tension spring 73 is an example of an elastic member, and it goes without saying that the first tension spring 73 can be replaced with another elastic member. Due to the deformation of the first biasing means 70, for example, a torsion spring can be used as the elastic member. Such a torsion spring can be disposed, for example, around the support shaft 62, and can be configured such that one end of the torsion spring is latched to the urging lever 71 and the other end is connected to the urging force adjusting member 60. .

  As shown in FIG. 8, the support member 58 on the downstream side in the paper feeding direction of the urging force adjusting member 60 is provided with an L-shaped arm 81 constituting the second rotating arm of the second urging means 80 and a pressing member contacting / separating means. A solenoid 90 is provided. The L-shaped arm 81 is rotatably supported by the support member 58 around the support shaft 81a.

  The L-shaped arm 81 has two arm portions (a first arm portion 81b and a second arm portion 81c), and the arm portions 81b and 81c are provided with an angle difference of approximately 90 degrees around the support shaft 81a. The state extends in different directions. The L-shaped arm 81 lays out a second tension spring 82, a solenoid 90, and a pressing portion 81d, which will be described later, in a compact layout. The angle difference of approximately 90 degrees described above is merely an example, and the two arm portions 81b and 81c of the L-shaped arm 81 are other than 90 degrees according to the layout of the second tension spring 82, the solenoid 90, and the pressing portion 81d. Of course, it can be set to an optimum angle.

  A pressing portion 81d that can contact the first pressed portion 51b of the first rotating arm 51 is formed at the tip of the first arm portion 81b. One end of the second tension spring 82 is connected to a spring hook 81e formed at the tip of the second arm 81c. The other end of the second tension spring 82 is fixed to the second spring hook 60 c of the biasing force adjusting member 60. Accordingly, the L-shaped arm 81 is constantly urged to rotate clockwise in FIG. 8 by the urging force of the second tension spring 82.

  The solenoid 90 has an operating shaft 90a that retracts when excited by a switch ON. The operating shaft 90 a is connected to the intermediate portion of the second arm portion 81 c of the L-shaped arm 81. Only when the solenoid 90 is turned ON, the L-shaped arm 81 resists the second tension spring 82, that is, cancels the biasing force of the second tension spring 82, and counterclockwise as shown in FIG. To turn. Thus, the first arm portion 81 b of the L-shaped arm 81 is separated from the first pressed portion 51 b of the first rotating arm 51.

  In a state where the pressing roller 50 is in contact with the uppermost surface of the sheet bundle, when the sheet is supplied and the upper surface position (height h in FIG. 3) of the sheet bundle is lowered, the first rotating arm 51 is rotated accordingly. It swings around the moving shaft 53. The photosensor 52 detects the displacement of the filler 51d accompanying the swing of the first rotating arm 51. Further, a push-up means (not shown) raises the bottom plate 32a of the paper feed tray 32 based on the detection signal of the photosensor 52 at that time, and the height h from the upper surface of the sheet bundle to the suction belt 33 is set to a predetermined height. Configured to maintain.

(Feeding operation)
Next, a paper feeding operation (paper feeding method) of the paper feeding device will be described. When a paper feed command is issued from the main body of the image forming apparatus, air is blown from the front blower 35 and the side blower 36 in FIG. 3 to the upper sheet of the loaded paper bundle, and at the same time, the suction of the suction belt 33 is started. The

  At this time, the solenoid 90 in FIG. 8 is turned off and is in an inoperative state. Therefore, the L-shaped arm 81 is rotated clockwise in FIG. 8 by the tensile force of the second tension spring 82, and the pressing portion 81 d at the tip of the first arm portion 81 b is the first rotation arm 51. The pressed part 51b is pushed down. As a result, the first rotation arm 51 rotates counterclockwise around the rotation shaft 53 against the first tension spring 73, and the pressing roller 50 is separated from the paper P1.

  Due to air suction of the suction belt 33, the first sheet at the top of the sheet bundle is lifted up to the height h of the suction belt 33 while being separated from the second and subsequent sheets and sucked to the lower surface of the suction belt 33. Is done. Then, in a state where the first sheet P1 is adsorbed by the adsorption belt 33, the adsorption belt 33 and the conveyance roller pair 37 start to rotate, and the first sheet is conveyed.

  Thereafter, when the first sheet reaches the sheet detection sensor 38 of FIG. 3 and is detected, the rotation of the suction belt 33 is stopped. Thereafter, the conveyance of the sheet is continued by the conveyance roller pair 37 while the suction belt 33 is stopped.

  Further, upon detection of the paper detection sensor 38, the solenoid 90 of FIG. Then, the L-shaped arm 81 is pulled against the second tension spring 82 by the operating shaft 90a of the solenoid 90, that is, to cancel the biasing force of the second tension spring 82, and counterclockwise as shown in FIG. To turn. As a result, the first arm portion 81 b of the L-shaped arm 81 is separated from the first pressed portion 51 b of the first rotating arm 51, and the first rotating arm 51 receives the biasing force of the first tension spring 73. The urging roller 72 is urged clockwise.

  As a result, the pressing roller 50 of the first rotating arm 51 comes into contact with the upper surface of the second sheet, and the upper surface position of the sheet bundle is detected. As a result of detecting the upper surface position of the sheet bundle, if the upper surface position is lower than a preset reference height h, the bottom plate 32a of the paper feed tray 32 is raised by a lifting means (not shown), and the upper surface of the sheet bundle is To the suction belt 33 is adjusted to a predetermined value. Further, when the detected upper surface position of the sheet bundle is not lower than the preset reference height h, the height adjustment is not performed.

  When the second sheet is conveyed subsequent to the upper surface position of the sheet bundle, the solenoid 90 is switched off, that is, inactive, in synchronization with the conveyance timing. As a result, the pressing roller 50 is separated from the sheet, and the sheet conveyance by the suction belt 33 is repeated.

(Adjustment change adjustment of paper pressing force by pressing force variable mechanism)
Next, the increase / decrease / change adjustment of the paper pressing force by the pressing force variable mechanism will be described. When transporting normal paper (plain paper), the urging force adjusting member 60 is slid slightly to the right (solenoid 90 side) from the position of FIG. 7 so that the set screw 61 is positioned in the middle of the long hole 60a1. To do. Thus, the urging roller 72 presses the intermediate portion in the longitudinal direction of the second pressed portion 51 c of the first rotating arm 51. Accordingly, the rotational moment of the first rotating arm 51 by the first tension spring 73 is medium, and the pressing force of the pressing roller 50 against the sheet is medium.

  On the other hand, at this time, the second spring hooking portion 60c of the biasing force adjusting member 60 moves to the intermediate position in the left-right direction in FIG. 7, and the spring hooking portion 81e of the L-shaped arm 81 is moderate by the second tension spring 82. Pulled by tensile force. As shown in FIG. 8, when the solenoid 90 is turned on to bring the pressing roller 50 into contact with the paper P <b> 1 as shown in FIG. 8, the L-shaped arm 81 resists the second tension spring 82 to the operating shaft 90 a of the solenoid 90. Be pulled.

  When the solenoid is turned OFF from this state, the L-shaped arm 81 is rotated clockwise in FIG. 8 by the tensile force of the second tension spring 82, and the pressing portion 81d at the tip of the first arm portion 81b is the first. The first pressed portion 51b of the rotating arm 51 is pushed down. As a result, the first rotating arm 51 rotates counterclockwise around the rotating shaft 53 against the first tension spring 73, and the pressing roller 50 is separated from the paper P1.

  When transporting easily damaged paper such as art paper, coated paper, non-carbon paper, or OHP film whose surface is coated, the biasing force adjusting member 60 is further moved to the right side (solenoid 90) in FIG. Slide to the side). That is, the urging force adjusting member 60 is slid so that the set screw 61 is positioned at the left end of the long hole 60a1.

  Thus, the urging roller 72 presses the portion closest to the rotation shaft 53 of the second pressed portion 51c of the first rotating arm 51 (the base end portion of the second pressed portion 51c). Accordingly, the rotational moment of the first rotating arm 51 by the first tension spring 73 is minimized, and the pressing force of the pressing roller 50 against the sheet is minimized. Therefore, even if the pressing roller 50 comes into contact with a sheet that is easily damaged, the sheet can be prevented from being damaged.

  On the other hand, at this time, the second spring hooking portion 60c of the urging force adjusting member 60 moves to the right end of FIG. 7 as indicated by the chain line, and the spring hooking portion 81e of the L-shaped arm 81 is minimized by the second tension spring 82. It is pulled by the pulling force. As shown in FIG. 8, when the solenoid 90 is turned on to bring the pressing roller 50 into contact with the paper P <b> 1 as shown in FIG. 8, the L-shaped arm 81 resists the second tension spring 82 to the operating shaft 90 a of the solenoid 90. Be pulled. At this time, the suction force of the solenoid 90 only needs to have a magnitude corresponding to the minimum pulling force of the second tension spring 82, so that the enlargement of the solenoid 90 can be avoided.

  When the solenoid is turned OFF from this state, the L-shaped arm 81 is rotated clockwise in FIG. 8 with the minimum tensile force of the second tension spring 82, and the pressing portion 81d at the tip of the first arm portion 81b is moved. The first pressed portion 51b of the first rotating arm 51 is pushed down. As a result, the first rotating arm 51 rotates counterclockwise around the rotating shaft 53 against the first tension spring 73, and the pressing roller 50 is separated from the paper P1.

  On the other hand, when transporting paper such as thick paper that is hard to be damaged and is strong, if the pressing force of the pressing roller 50 is weak, the pressing force of the pressing roller 50 is lost to the strength of the paper. In this case, The pressing force by the pressing roller 50 is increased. That is, in order to increase the pressing force against the paper, the urging force adjusting member is slid to the left as shown by the solid line in FIG. 7 so that the set screw 61 is positioned at the right end of the long hole 60a1.

  Thus, the urging roller 72 presses the portion farthest from the rotation shaft 53 of the second pressed portion 51c of the first rotating arm 51 (the tip portion of the second pressed portion 51c). Accordingly, the rotational moment of the first rotating arm 51 by the first tension spring 73 is maximized, and the pressing force of the pressing roller 50 against the sheet is maximized. As a result, a pressing force comparable to the stiffness of paper such as thick paper can be obtained, and accurate detection of the upper surface position of the paper and reliable conveyance of the paper can thereby be achieved.

  On the other hand, at this time, the second spring hooking portion 60c of the biasing force adjusting member 60 moves to the left end of FIG. 7 as indicated by the solid line, and the spring hooking portion 81e of the L-shaped arm 81 is maximized by the second tension spring 82. It is pulled by the pulling force. As shown in FIG. 8, when the solenoid 90 is turned on to bring the pressing roller 50 into contact with the paper P <b> 1 as shown in FIG. 8, the L-shaped arm 81 resists the second tension spring 82 to the operating shaft 90 a of the solenoid 90. Be pulled. At this time, the attractive force of the solenoid 90 is set to a magnitude corresponding to the maximum tensile force of the second tension spring 82. That is, the solenoid 90 may be enlarged only in the case of a paper feeding device that supplies paper such as cardboard.

  When the solenoid is turned OFF from this state, the L-shaped arm 81 is rotated clockwise in FIG. 8 by the maximum tensile force of the second tension spring 82, and the pressing portion 81d at the tip of the first arm portion 81b is moved. The first pressed portion 51b of the first rotating arm 51 is pushed down. As a result, the first rotating arm 51 rotates counterclockwise around the rotating shaft 53 against the first tension spring 73, and the pressing roller 50 is separated from the paper P1.

  In this manner, the paper pressing force of the pressing roller 50 is maximized by sliding the urging force adjusting member 60 and changing the position of the urging roller 72 on the second pressed portion 51c of the first rotating arm 51. It is possible to adjust in a wide range to the minimum. Therefore, it is possible to easily optimize the pressing force against various types of paper.

  In addition, the tensile force of the second tension spring 82 can be increased or decreased in accordance with the pressing force in a manner linked with the wide range adjustment of the paper pressing force of the pressing roller 50. For this reason, when the paper pressing force of the pressing roller 50 is reduced, the L-shaped arm 81 can be driven by the small solenoid 90 without replacing the second tension spring 82. Therefore, it is possible to avoid the uniform enlargement of the solenoid 90 in the apparatus having a small paper pressing force, thereby reducing the power consumption and the cost of the apparatus.

(Adjusting the height of the top surface of the paper)
The height h of the paper upper surface position is raised by raising the bottom plate 32a of the paper feed tray 32 when the upper surface position of the sheet bundle is lower than a preset reference height, as described in the paper feeding operation. The height is adjusted so that the height h from the upper surface of the sheet bundle to the suction belt 33 becomes a predetermined value. Whether or not the upper surface position of the sheet bundle is below a preset reference height is determined by whether or not the filler 51d of the first rotating arm 51 to which the pressing roller 50 is attached shields the photosensor 52 from light. Is done.

  When the position of the upper surface of the sheet bundle is lowered, the filler 51d shown in FIG. 6B is lowered along with the counterclockwise rotation of the first rotation arm 51 around the rotation shaft 53. Then, at the height of the pressing roller 50 when the filler 51d blocks the optical axis of the photosensor 52, the bottom plate 32a of the paper feed tray 32 starts to be raised by the lifting means. That is, the height adjustment is started when the elevating means receives the signal from the photosensor 52 and raises the bottom plate 32 a of the paper feed tray 32. When the height of the filler 51d rises due to this height adjustment, and the light from the light projecting portion of the photosensor 52 passes through the light receiving portion again, the height adjustment ends.

In a general paper feeder, the height h from the upper surface of the sheet bundle to the suction belt 33 is constant. If the height h is constant, there is a problem when transporting thin paper or thick paper having a thickness different from that of plain paper. In the case of thin paper, it is difficult for the uppermost sheet and the lower sheet to be separated, and the sheet may be attracted to the suction belt 33 as a bundle of a plurality of sheets and conveyed (multi-feed) as it is. Further, when the weight (g / m ² ) is large, such as cardboard, it takes time to be sucked by the suction belt 33. For this reason, idle feeding may occur without being attracted to the suction belt 33. For such a case, the height h can be increased or decreased by rotating the grip 335 in FIG. 12A (FIG. 12B) according to the type of paper to be conveyed.

  That is, when transporting thin paper, the grip 335 is turned to lower the position of the photosensor 52 by the rotation of the rotation shaft 53 (312). When transporting thick paper, the grip 335 is rotated in the opposite direction to raise the position of the photosensor 52. In both cases of thin paper and thick paper, the grip 335 can be rotated in a stepless manner, so that the height h of the top surface of the paper can be finely adjusted, and the paper can be normally fed from thin paper to thick paper regardless of the weighing amount. With this, paper handling ability can be strengthened.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in the embodiment, the first and second urging means are configured by the first tension spring 73 and the second tension spring 82, respectively. However, the first and second urging means can be configured by using an elastic member other than the tension spring. In addition, the paper feeding device (recording medium supply device) according to the present invention is not limited to the color image forming device shown in FIG. 1, but a monochrome image forming device, other copying machines, printers, facsimiles, or complex machines thereof. It is also possible to provide it.

  Further, the recording medium supply device of the present invention is applicable not only to an air separation paper feeding device but also to a friction separation roller type paper feeding device called an FRR method (Feed Riverse Roller) as shown in FIG. That is, the paper feeding device shown in FIG. 8 is applied to the paper feeding device in FIG. 9, and the pressing roller 50 in FIG. 8 is used for the calling roller 150 in FIG. In FIG. 9, 151 is a paper feed tray, 152 is a paper guide, 153 is a bottom plate, 153a is a rotation shaft, 155 is a feed roller, 156a is a separation roller, 156a is an urging spring, 158 is a grip roller, and K1 is a front end. A detection unit K2 is a sheet detection unit.

  The separation roller 156 is given a driving force in a direction opposite to the feeding direction via a torque limiter. The sheet is called from the sheet bundle by the rotation of the calling roller 150 geared to the feed roller 155. The calling roller 150 comes into contact with the uppermost sheet and feeds the sheet (preceding sheet P1) downstream in the transport direction.

  The fed preceding paper P1 is fed downstream in the transport direction by a feed roller 155 located on the downstream side of the paper feed tray 151. Even before the trailing edge of the preceding paper P1 passes through the grounding point of the calling roller 150, when the leading edge of the preceding paper P1 reaches the grip roller 158 provided further downstream, the calling roller 150 becomes the paper surface of the preceding paper. Spaced apart (or undriven).

  When the front end of the preceding paper P1 is detected by the paper detection means K2 further downstream of the grip roller 158, the calling roller 150 is triggered by this paper detection to trigger the uppermost paper (next paper P2) on the paper feed tray 151. It is brought into contact again with the paper surface or re-driven. As a result, the next sheet P2 is fed out. In this way, the calling roller 150 repeats contact and separation with respect to the sheet, and this contact / separation is switched by ON / OFF of the solenoid 90 in FIG.

1: Image forming apparatus 2: Image forming apparatus main body 3: Paper feed devices 4Y, 4C, 4M, 4Bk: Process unit 5: Photoconductor 6: Charging roller 7: Developing device 8: Cleaning blade 9: Exposure device 10: Transfer device 15: intermediate transfer belt 16: primary transfer roller 17: secondary transfer roller 18: paper discharge tray 19: timing roller pair 20: fixing device 21: paper discharge roller pair 32: paper feed tray 33: suction belt 34: upper surface position detection Device 35: Front blower 36: Side blower 37: Conveying roller pair 38: Paper detection sensor 41: Suction belt unit 42: Drive roller 43: Driven roller 44: Drive motor 45: Suction chamber 46: Suction duct 50: Pressing roller 51: 1st rotation arm 51a: Arm part 51b: 1st pressed part 51c: 2nd pressed part 51d: Filler 52: Photo Sensor 53: Rotating shaft 54: Bracket 58: Support member 58a: Emboss 60: Biasing force adjusting member 60a1, 60a2 :: Slot 60b: First spring hook 60c: Second spring hook 61: Screw 62: Support shaft 70: first urging means 71: urging lever 71a: spring hooking portion 72: urging roller 73: first tension spring 80: second urging means 81: L-shaped arm 81a: support shaft 81b: first arm Part 81c: Second arm part 81d: Pressing part 81e: Spring hook part 82: Second tension spring 90: Solenoid 90a: Actuating shaft 150: Calling roller 151: Paper feed tray 155: Feed roller 156: Separating roller 158: Grip roller 301: Air separation paper feeder 302: Paper feed tray 303: Front blower 304: Side blower 305: Suction belt 306: Front fence 307 Support plate 310: swinging member 311: rotary arm 313: pressing roller 320: swing detecting sensor 321: the photosensor 322: filler 330: pressing lever 332: urging roller 333: a tension spring 334: operation lever 335: Grip

JP 2001-247229 A JP 2007-45630 A JP 2011-73864 A

Claims (10)

In the recording medium supply apparatus configured to press the pressing member disposed at one end of the first rotating arm against the uppermost surface of the sheet-like recording medium mounted in a stacked state on the recording medium mounting section,
First urging means for applying a pressing force to the pressing member by urging the first rotating arm in the rotating direction is arranged to be movable along the longitudinal direction of the first rotating arm. A recording medium supply apparatus in which the pressing force of the pressing member can be changed by moving the first urging means. Second urging means for urging the pressing member in a direction away from the uppermost surface of the recording medium with an urging force larger than the urging force of the first urging means;
The pressing member is separated from the uppermost surface of the recording medium by the biasing force of the second biasing means in the non-operating state, and the pressing member is offset by canceling the biasing force of the second biasing means in the operating state. A pressing member contacting / separating means for contacting the uppermost surface of the recording medium with the urging force of the first urging means;
The recording medium supply device according to claim 1, comprising:   3. A recording medium supply apparatus according to claim 2, further comprising interlocking means for increasing or decreasing the biasing forces of the first biasing means and the second biasing means in conjunction with each other.   4. The recording medium supply device according to claim 1, further comprising an upper surface position detecting unit configured to detect a height position of an uppermost surface of the recording medium based on a height position of the pressing member.   The recording medium supply apparatus according to claim 4, further comprising an elevating unit that changes a height of the recording medium mounting unit based on a detection result of the upper surface position detecting unit. An air discharge means for blowing air onto the recording medium in the laminated state to float one recording medium at the uppermost position;
Transport means for sucking and transporting the one recording medium that has been levitated;
By switching the pressing member contacting / separating means from the operating state to the non-operating state in synchronization with the recording medium conveying timing by the conveying means, the uppermost surface of the recording medium is contacted by the urging force of the first urging means. Control means for separating the pressing member that has been separated from the uppermost surface of the recording medium by the urging force of the second urging means;
The recording medium supply device according to claim 2, further comprising: The first urging means has an urging roller in contact with the first rotating arm, an urging lever that supports the urging roller at one end, and the urging roller toward the first rotating arm. A first tension spring coupled to the other end of the biasing lever so as to bias
The second urging means is connected to a second rotating arm, one end of which is disposed so as to be able to contact and separate from the first rotating arm, and the other end of the second rotating arm. A second tension spring that urges the pressing member in a direction away from the uppermost surface of the recording medium in a state where one end of the rotating arm is in contact with the first rotating arm;
The recording medium supply device according to claim 2, wherein the pressing member contacting / separating means includes a solenoid coupled to the second rotating arm.   The second rotation arm has a first arm portion and a second arm portion that extend in different directions from a rotation shaft that rotatably supports the second rotation arm, and A distal end portion is disposed so as to be able to contact and separate from the other end portion of the first rotating arm, and one end portion of the second tension spring is connected to the distal end portion of the second arm portion. The recording medium supply device according to claim 7, wherein the solenoid is connected to a portion. The interlocking means supports the first tension spring, the urging lever and the urging roller as a unit, and has a slidable urging force adjusting member connected to the other end of the second tension spring. ,
The sliding position of the biasing force adjusting member changes the contact position of the biasing roller with respect to the first rotating arm, thereby changing the biasing force of the pressing member against the uppermost surface of the recording medium. 9. The recording medium supply apparatus according to claim 7, wherein the urging force of the two tension springs is changed.   An image forming apparatus comprising the recording medium supply device according to claim 1.