JP2013095557A - Recording medium supplying device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium supplying device that can adjust the height from the topmost surface of a paper bundle to a suction belt depending on the kind of paper to be conveyed so that the paper is separated sheet by sheet without fail, is sucked by the suction belt without fail, and can be conveyed.SOLUTION: The recording medium supplying device includes: a recording medium loading part that can load sheet-like recording medium in a stacked state; an air discharging means that blows air onto the recording medium in the stacked state to levitate a sheet of recording medium from the topmost position; a conveying means that sucks to convey the recording medium levitated from the topmost position; a topmost surface position detection means that contacts with the topmost surface of the recording medium in the stacked state to detect the height position in contact with the topmost surface; a lifting means that moves the recording medium loading part up and down in the vertical direction; and a control means that controls the lifting means so that the top surface height of the recording medium in the stacked state becomes a predetermined height based on the topmost surface position detected by the topmost surface position detection means. This recording media supplying device is provided with a height adjustment mechanism (height adjuster 75) that adjusts the height from the top surface to the conveying means.

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.

  2. Description of the Related Art In image forming apparatuses such as copying machines, printers, facsimiles, and multifunction machines of these, paper feeding apparatuses that supply paper, OHP films, etc. one by one are known. In the sheet feeding device, air is blown to the bundled sheets mounted in a stacked state on the tray so that the sheets (recording media) are floated and separated from each other, and the uppermost sheet is sucked by the suction force. There is an air separation paper feeding device that is adsorbed to and transported. 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. 13 shows a schematic configuration of the air separation sheet feeding device.
13 includes a tray 302 on which a plurality of sheets P are mounted, a front blower 303 and a side blower 304 that blow air on the upper front end and the upper side end of the loaded sheets P, and A suction belt 305 is provided for sucking and transporting the paper Ps one by one. The paper P is aligned on the tray 302 so as to match the size of the paper P by placing the front end face against a front fence 306 as a reference surface.

  In order to supply the paper P by the air separating / feeding device 301, first, air is blown from the front blower 303 and the side blower 304 toward the bundle of the paper P mounted on the tray 302, and this air causes the space between the papers P to be supplied. Air is sent to the height h of the suction belt 305 while the paper P is being rolled up. 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.

  In addition, the air separating and feeding apparatus described in Patent Documents 1 and 2 includes an upper surface position detecting unit that detects the position of the uppermost surface of the loaded paper. As the upper surface position detecting means, for example, as shown in FIG. 13, an actuator 310 that is configured to be in contact with the uppermost surface of the sheet bundle and swingable, and a swing detection sensor 311 that detects the swing of the actuator 310. Some have The mounting position of the actuator 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 this case, when the sheet is supplied and the height of the sheet bundle is lowered, the actuator 310 swings accordingly. Then, the swing detection sensor 311 detects the swing amount of the actuator 310, and the lifting means (not shown) raises the bottom plate of the tray 302 based on the detection signal at that time, so that the suction belt 305 is lifted from the upper surface of the sheet bundle. The height h (distance) is controlled to be constant.

In recent years, an air separation and feeding apparatus is required to have a capability of reliably transporting paper regardless of a wide paper thickness from thin paper to thick paper, paper type, and weighing (g / m ² ). However, since the height h from the uppermost surface of the sheet bundle to the suction belt is constant in the conventional paper feeder, there are the following problems when transporting thin paper or thick paper having a thickness different from that of plain paper There was found. That is, in the case of thin paper with a light weight, it is difficult to separate the uppermost sheet and the lower sheet, and the sheet may be adsorbed to the adsorption belt 33 as a bundle of a plurality of sheets and conveyed (multi-feed) as it is. . Further, in the case of heavy paper with a heavy weight, it takes time until it is sucked by the suction belt 33, so that it may not be sucked by the suction belt 33 and may cause an idle feed.

  The present invention has been made in view of the above-described problems, and makes it possible to adjust the height from the uppermost surface of the sheet bundle to the suction belt according to the type of sheet to be conveyed, thereby ensuring that one sheet of paper The purpose is to separate them one by one and reliably suck them with a suction belt.

  The invention according to claim 1 is a recording medium mounting portion on which a sheet-like recording medium can be mounted in a stacked state, and an air discharge unit that blows air onto the stacked recording medium to float one recording medium at the uppermost position. A conveying means for adsorbing and conveying the one recording medium that has been levitated, an upper surface position detecting means for contacting the uppermost surface of the stacked recording medium and detecting its height position; and Based on the raising / lowering means for raising / lowering the recording medium mounting portion in the vertical direction and the uppermost surface position detected by the upper surface position detecting means, the uppermost surface height of the recording medium in the stacked state becomes a predetermined height. In the sheet feeding device including a control unit that controls the lifting unit, the recording medium supply device includes a height adjustment mechanism that adjusts a height from the uppermost surface to the transport unit.

  Since the present invention has a height adjustment mechanism that adjusts the height from the uppermost surface of the recording medium to the conveying means, the height from the uppermost surface of the recording medium to the conveying means is adjusted according to the type of the recording medium to be conveyed. As a result, the recording media can be reliably separated one by one and reliably adsorbed and conveyed by the conveying means.

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 feeder. It is a perspective view which shows the internal structure of a paper feeder. It is the perspective view which looked at the adsorption belt unit from the bottom. It is the perspective view which looked at the height adjustment apparatus provided in the adsorption belt unit from the bottom. It is a side view of a height adjustment apparatus. It is a side view of the state which raised the photo sensor with the height adjusting device. It is a side view of the state which made the photo sensor low with the height adjustment apparatus. It is a schematic block diagram of the conventional air separation paper feeder.

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 for 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 to distinguish them, and then the explanation will be given. Is omitted.

(Image forming device)
FIG. 1 is an external view showing an embodiment of an image forming apparatus provided with a sheet feeding device according to an embodiment of the present invention.
As shown in FIG. 1, the image forming apparatus 1 includes an image forming apparatus main body 2 and a paper feeding apparatus that is connected to one side surface of the image forming apparatus main body 2 and supplies paper to the image forming apparatus main body 2. 3.

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, a charging roller 6 as a charging unit that charges the surface of the photosensitive member 5, and the photosensitive member 5. A developing device 7 as a developing means for forming a toner image on the surface of the photosensitive member 5 and a cleaning blade 8 as a cleaning means for cleaning the surface of the photoreceptor 5.

  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 presses the inner peripheral surface of the intermediate transfer belt 15 at each position, and a primary transfer nip is formed at a place where the pressed portion of the intermediate transfer belt 15 and each photoconductor 5 are in contact with each other. ing. 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 presses 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 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 pair of paper discharge rollers 21 are disposed on the downstream side 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 pressure contact with each other, and a fixing nip is formed at the pressure contact portion.

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 19 and the secondary transfer nip between the secondary transfer roller 17 and the intermediate transfer belt 15. Sent to. 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 paper is discharged to the paper discharge tray 18 by the pair of paper discharge rollers 21.

  The above description is an image forming operation when a full-color image is formed on a sheet. A single-color image is formed using any one of the four process units 4Y, 4C, 4M, and 4Bk. Alternatively, it is possible to form two-color or three-color images using three process units.

(Paper feeder)
Next, the configuration of the paper feeding device according to the embodiment of the recording medium supply device of the present invention will be described with reference to FIGS. FIG. 3 is a schematic configuration diagram of the entire sheet feeding device 3. The paper feeding device 3 shown in FIG. 1 is equipped with a paper feeding tray 32 as a recording medium mounting portion on which a plurality of paper sheets P can be stacked and a suction belt 33 as a transporting means for transporting paper. An upper surface position detecting device 34 as an upper surface position detecting means for detecting the upper surface position of the sheet bundle, and a push-up means (not shown) that raises the height of the upper surface of the sheet bundle to a predetermined height based on the detection result of the upper surface position detecting device 34. And a front blower 35 and a side blower 36 as air discharge means for blowing air onto the loaded sheet bundle to float one sheet at the uppermost position, and disposed downstream of the suction belt 33 in the sheet conveying direction. A pair of transport rollers 37 and a paper detection sensor 38 disposed further downstream are provided.

  The upper surface position detection device 34 includes an actuator 40, a photo sensor 41, a pressing roller 42 as a pressing member, an urging lever 43 and an urging roller 44 as urging means. Here, “biasing means” refers to means for applying an elastic force. Details of the upper surface position detector 34 will be described later.

  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. The paper can be exchanged or replenished with respect 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 the internal structure of the paper feeding device of the present invention.
As shown in FIG. 4, the paper feed tray 32 as a recording medium mounting portion has a box shape with the top opened. The paper feed tray 32 positions the bottom plate 32a, the front fence 32b for positioning the front end of the sheet bundle mounted on the bottom plate 32a in the conveyance direction, and both ends of the sheet bundle in the width direction (direction perpendicular to the conveyance direction). A pair of side fences 32c and an end fence 32d for positioning the rear end in the transport direction of the sheet bundle are provided. The replacement or replenishment of paper is performed from above the paper feed tray 32.

  A suction belt unit 48 having the suction belt 33 and the like above the front fence 32b of the paper feed tray 32 crosses the upper side of the paper feed tray 32 in the width direction (perpendicular to the paper surface as viewed in FIG. 3). It is attached with. A suction duct 49 is connected to the suction belt unit 48. The suction belt unit 48 includes a first support member 57 and a second support member 58, and the suction belt 33 is disposed below the first support member 57. The reason why the first and second support members 57 and 58 are divided is mainly to facilitate assembly, and the two support members 57 and 58 can be integrated into one support member. It is.

FIG. 5 shows the paper feeder of FIG. 4 with the suction belt unit 48 removed.
As shown in FIG. 5, one front air discharge port 35a 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 on the upper portions of the two side fences 32c, respectively. . These discharge ports 35a and 36a are respectively connected to a front blower 35 and a side blower 36 disposed in each fence via a duct (not shown). The air discharged from the discharge ports 35 a and 36 a is blown onto the upper layer of the sheet bundle mounted on the paper feed tray 32.

  FIG. 6 is a perspective view of the suction belt unit 48 shown in FIG. 4 as viewed from below. As shown in FIG. 6, the suction belt unit 48 includes a suction belt 33, a drive motor 50 as a driving unit that rotationally drives the suction belt 33, and a suction duct 49 that connects the suction belt unit 48 to a suction blower (not shown). And the upper surface position detection device 34. Except for the upper surface position detection device 34, the first support member 57 is disposed, and the upper surface position detection device 34 is disposed on the second support member 58.

  The suction belt 33 is stretched between the driving roller 51 and the driven roller 52 in a state where a predetermined tension is applied. When the drive motor 50 is connected to the drive roller 51 and the drive motor 50 is driven at a preset paper feed timing, the drive roller 51 is driven to rotate and the suction belt 33 rotates in the direction of the arrow. .

  A box-shaped suction chamber 53 having a downward opening (upward in FIG. 6) is provided in an area between the driving roller 51 and the driven roller 52 and surrounded by the suction belt 33. The suction chamber 53 is connected to a suction blower (not shown) via a suction duct 49. When the suction blower (not shown) is driven and air is sucked from the suction chamber 53 through the suction duct 49, the inside of the suction chamber 53 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.

  A rotation shaft 77 is arranged on the side of the driven roller 52 of the suction belt 33 in parallel with the driven roller 52. The rotating shaft 77 is arranged on the second support member 58 as shown in FIG. 7, and a photo sensor 41 is attached as will be described later to constitute a height adjusting device 75. One end of the rotation shaft 77 is connected to a polygonal columnar grip 78 as an operation portion arranged on the access side (front side of the paper feeding device 3) of the first support member 57 via the torque limiter 80 and the shaft portion 80a. It is connected. Then, by rotating the grip 78 in the clockwise direction, the position of the photosensor 41 described later can be lowered, and on the contrary, by rotating in the counterclockwise direction, the position of the photosensor 41 can be increased. It has become. On the other hand, as can be seen from FIG. 7, an actuator 40 described later is rotatably attached to the other end of the rotation shaft 77.

  The rotation shaft 77 described above is restricted from being freely rotated by the restraining force of the torque limiter 80. As the torque limiter 80, for example, a known coil spring method or powder method can be used. The grip 78 is for rotating the rotating shaft 77 steplessly against the torque limiter 80. Instead of the torque limiter 80, a lock member that locks the rotation position in stages may be provided.

The actuator 40 is rotatably attached to the back end portion (the side opposite to the access side) of the rotation shaft 77. An integral photosensor 41 in which a light projecting portion and a light receiving portion are arranged to face each other is attached to a rotation shaft 77 near the actuator 40 via a bracket 79. The photo sensor 41 is for detecting the rotational position of the actuator 40, and it is needless to say that the photo sensor 41 can be replaced with another sensor having an equivalent function regardless of contact type or non-contact type.
In this embodiment, the photosensor 41, which is a constituent member of the upper surface position detection device, is moved to the rotation shaft 77 that is coaxial with the axis (the rotation axis of the actuator 40) that is the center of oscillation of the pressing roller 42 as the pressing member. By attaching, the device can be made compact.

  The actuator 40 is formed by bending a sheet metal into a gate shape (gate shape), and a filler 40 a is formed on one side of the actuator 40 so as to project outward in the radial direction when viewed from the rotation shaft 77. Then, the light projecting portion and the light receiving portion of the photosensor 41 are arranged so as to sandwich the filler 40a from both sides, and the photosensor 41 detects whether or not the actuator 40 has reached a predetermined rotation position. It has become. On the other hand, a horizontally extending arm portion 40 b is formed on the opposite side of the actuator 40, and a pressing roller 42 that presses the top surface of the paper is rotatably attached to the tip of the arm portion 40 b by a support shaft 45. The pressing roller 42 is positioned approximately at the center in the width direction of the paper feed tray 32 and has its support shaft 45 oriented in a direction perpendicular to the paper feed direction.

  The filler 40a and the arm portion 40b of the actuator 40 are connected by a substantially horizontal connecting plate portion 40c, and an urging roller 44 has a predetermined contact with the upper surface of the connecting plate portion 40c as schematically shown in FIG. Contact with pressure. Accordingly, the actuator 40 is urged counterclockwise in FIG. 3 by the urging force of the urging roller 44, and the pressing roller 42 applies a predetermined pressing force substantially at the center in the width direction of the top surface of the sheet.

  When the sheet is supplied and the upper surface position (height) of the sheet bundle is lowered in a state where the pressing roller 42 is in contact with the upper surface of the sheet bundle, the actuator 40 swings around the rotation shaft 77 following that. . The photo sensor 41 detects the displacement of the filler 40a accompanying the swing of the actuator 40. 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 41 at that time, and the height h from the upper surface of the sheet bundle to the suction belt 33 (see FIG. 3). Is maintained at a predetermined height.

(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 image forming apparatus main body, air is blown onto the upper sheet of the sheet bundle loaded from the blower (front blower 35 and side blower 36), and at the same time, air suction of the suction belt 33 is started. Accordingly, the first sheet at the uppermost position 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 is sucked to the lower surface of the suction belt 33. Then, in a state where the first sheet is adsorbed to the adsorption belt 33, the rotation of the adsorption belt 33 and the conveyance roller 37 is started to convey the first sheet.

  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. The conveyance roller 37 continues to convey the sheet with the suction belt 33 stopped. The pressing roller 42 of the actuator 40 comes into contact with the upper surface of the second sheet, and the position of the upper surface of the sheet bundle is detected. As a result of detecting the upper surface position of the sheet bundle, when the upper surface position is lower than a preset reference height, 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 so that the height h (distance) becomes a predetermined value. Further, when the detected upper surface position of the sheet bundle is not lower than a preset reference height, the height adjustment is not performed.

(Adjusting the height of the top surface of the paper)
Next, adjustment of the height h of the sheet upper surface position will be described.
As described in the sheet feeding operation, when the upper surface position of the sheet bundle is below a preset reference height, the bottom plate 32a of the sheet feed tray 32 is raised to the suction belt 33 from the upper surface of the sheet bundle. The height h is adjusted so that the height h (distance) 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 40a of the actuator 40 to which the pressing roller 42 is attached shields the photo sensor 41 from light.

  When the upper surface position of the sheet bundle is lowered, the light shielding portion of the filler 40 a shown in FIG. 10 is lowered along with the counterclockwise rotation of the actuator 40 around the rotation shaft 77. Then, at the height of the pressing roller 42 when the light shielding portion blocks the optical axis of the photosensor 41, the bottom plate 32a of the paper feed tray 32 starts to be raised by the pushing-up means. That is, when the push-up means receives a signal from the photosensor 41 and raises the bottom plate 32a of the paper feed tray 32, the height adjustment is started. By this height adjustment, the light shielding portion of the filler 40a is raised, and when the light of the light projecting portion of the photosensor 41 again passes through the light receiving portion, the height adjustment is finished (the height h becomes a predetermined value). ).

  In a general paper feeder, the height h from the upper surface of the sheet bundle to the suction belt 33 is constant. However, 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. That is, in the case of thin paper with a light weight, it is difficult to separate the uppermost sheet and the lower sheet, and the sheet may be adsorbed to the adsorption belt 33 as a bundle of a plurality of sheets and conveyed (multi-feed) as it is. . Further, in the case of heavy paper with a heavy weight, it takes time until it is sucked by the suction belt 33, so that it may not be sucked by the suction belt 33 and may cause an idle feed. In this embodiment, the height h can be increased or decreased by rotating the grip 78 according to the type of paper to be conveyed.

  That is, when carrying thin paper, the grip 78 is rotated by a necessary predetermined amount in the direction of arrow A in FIG. Thereby, the rotation shaft 77 connected to the grip 78 rotates in the same direction, and the position of the photosensor 41 is lowered as shown in FIG. 9A. Then, when the bottom plate 32a of the paper feed tray 32 is raised by the push-up means, the light shielding portion of the filler 40a is quickly released from the optical axis of the photosensor 41 by the lower amount. As a result, the rising time of the bottom plate 32a of the paper feed tray 32 by the push-up means is shortened, the height h is increased, and the thin paper is reliably separated.

  On the other hand, when conveying thick paper, the grip 78 is rotated by a necessary predetermined amount in the direction of the arrow B opposite to FIG. As a result, the rotation shaft 77 connected to the grip 78 rotates in the same direction, and the position of the photosensor 41 becomes higher as shown in FIG. 9B. Then, when the bottom plate 32a of the paper feed tray 32 is raised by the push-up means, the light shielding portion of the filler 40a is delayed from being removed from the optical axis of the photosensor 41 by the increased amount. As a result, the raising time of the bottom plate 32a of the paper feed tray 32 by the push-up means is lengthened, the height h is reduced, and the thick paper is reliably attracted to the suction belt 33.

  For both thin paper and thick paper, the grip 78 can be rotated and rotated steplessly. Therefore, the height h of the top surface of the paper can be finely adjusted according to the weighing, and normal paper can be fed from thin paper to thick paper. The paper handling ability can be strengthened. Since the grip 78 is located on the access side (front side of the paper feeding device 3) of the first support member 57, that is, on the front side end of the paper feeding tray 32, the upper surface of the paper without taking out the paper feeding tray 32 from the device main body. The height h can be easily adjusted. The height h of the sheet upper surface position can be adjusted as described above.

  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. 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.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming apparatus main body 3 Paper feeding apparatus (recording medium supply apparatus)
32 Paper feed tray (recording medium loading section)
33 Adsorption belt (conveying means)
34 Upper surface position detecting device (upper surface position detecting means)
35 Front blower (air discharge means)
36 Side blower (Air discharge means)
40 Actuator 40a Filler 41 Photosensor 42 Pressing roller 43 Energizing lever 44 Energizing roller 48 Suction belt unit 75 Height adjusting device (height adjusting mechanism)
77 Rotating shaft 78 Grip 80 Torque limiter

JP 2001-247229 A JP 2007-45630 A

Claims (7)

A recording medium mounting portion on which the sheet-like recording medium can be mounted in a stacked state; air discharge means for blowing air onto the recording medium in the stacked state to float one recording medium at the uppermost position; Conveying means for adsorbing and conveying a single recording medium, upper surface position detecting means for detecting the height position of the recording medium in contact with the uppermost surface of the stacked recording medium, and the recording medium mounting portion in the vertical direction And a control unit for controlling the elevating means so that the uppermost surface height of the recording medium in the stacked state becomes a predetermined height based on the uppermost surface position detected by the upper surface position detecting means. In a paper feeding device comprising means,
A recording medium supply apparatus having a height adjustment mechanism for adjusting a height from the uppermost surface to the transport unit.   The upper surface position detection means includes a pressing member that contacts the uppermost surface of the recording medium, and an upper surface position detection device that detects a height position of the pressing member, and the height adjustment mechanism includes the upper surface position detection device. The recording medium supply apparatus according to claim 1, further comprising a height adjusting device that makes a height position of the recording medium variable.   The pressing member is attached to a swingable actuator that swings the pressing member around a predetermined axis and presses the pressing member against the uppermost surface with a predetermined force, and the upper surface position detection device is rotated around the same axis as the axis. The recording medium supply device according to claim 2 attached to a moving shaft.   The recording medium supply apparatus according to claim 3, wherein the rotation shaft can be continuously positioned at a desired rotation position.   The recording medium supply apparatus according to claim 3, wherein the rotation shaft can be positioned at a desired rotation position stepwise.   The recording medium supply apparatus according to claim 3, wherein one end of the rotation shaft is disposed as an operation unit on the access side of the previous recording medium mounting unit.   An image forming apparatus comprising the recording medium supply device according to claim 1.

Images