JP2017039588A - Sheet conveyance device and image formation apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveyance device which can reduce the load to a sheet with respect to an actuator when the conveyed sheet collides with the actuator and effectively prevent the inconvenience (for example, transfer slippage) due to the load, and an image formation apparatus having the same.SOLUTION: A sheet conveyance device includes a sheet detection device which detects a sheet by rotating in the detection side rotation direction being the rotation direction to the detection side around a rotation axial line with contact of the sheet conveyed in a predetermined prescribed conveyance direction to the actuator rotating around the rotation axial line. The actuator is configured so that the center of gravity is located at the position other than the virtual vertical line passing through the rotation axial line in a posture at the time of contact to the conveyed sheet and the deadweight side rotation direction being the rotation direction to the deadweight side rotating around the rotation axial line due to the deadweight is the same as the detection side rotation direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet conveying apparatus including a sheet detecting apparatus that detects a sheet conveyed in a predetermined conveyance direction, and an image forming apparatus such as a copying machine, a multifunction machine, a printer, and a facsimile apparatus including the sheet conveying apparatus.

  As a sheet conveyance device that conveys a sheet in a predetermined conveyance direction, for example, a sheet detection device that detects a sheet conveyed in the conveyance direction in order to detect a conveyance state of the sheet such as a conveyance timing of the sheet is provided. Things are known.

  In addition, as a sheet detection device provided in the sheet conveyance device, for example, an actuator that rotates around a rotation axis is provided, and a sheet that is conveyed in the conveyance direction comes into contact with the actuator to detect around the rotation axis. 2. Description of the Related Art Conventionally, a sheet that rotates in a detection-side rotation direction that is a rotation direction to the side and detects a sheet is known.

  In addition, the sheet conveying device, for example, charges the surface of a photosensitive member (for example, a photosensitive drum) that acts as an image carrier (specifically, an electrostatic latent image carrier), exposes the image to the charged region, and statically An electrostatic latent image is formed, the electrostatic latent image is visualized (developed) as a toner image, and the visualized toner image is transferred to an intermediate transfer member such as an intermediate transfer belt or a recording sheet such as recording paper. When the toner image is transferred to the intermediate transfer member, the toner image may be further transferred to a recording sheet, and the toner image may be fixed to the recording sheet onto which the toner image is transferred.

JP 2006-10722 A

  In such a sheet conveying apparatus provided with a sheet detection apparatus, when the conveyed sheet collides with the actuator, a problem may occur due to a load (impact) on the sheet with respect to the actuator.

  For example, in an image forming apparatus that includes a sheet conveyance device including a sheet detection device and a transfer unit that transfers an image to a recording sheet that acts as a sheet, the recording sheet in the middle of the sheet detection device passing through the transfer unit When the recording sheet to be conveyed enters the actuator, a light brake is applied to the recording sheet due to the impact, and as a result, an image defect in which the transferred image shifts in the conveying direction (so-called transfer misalignment). ) May occur.

  In this regard, Patent Document 1 detects the loop amount of the recording paper in the conveyance path in order to prevent transfer misalignment accompanying the conveyance of the recording paper, and controls the rotation speed of the conveyance roller pair according to the detection result. The configuration is disclosed.

  However, in the configuration disclosed in Patent Document 1, when the conveyed sheet collides with the actuator, the load on the sheet with respect to the actuator is reduced to prevent inconvenience (for example, transfer misalignment) due to the load. Absent.

  Therefore, according to the present invention, when the conveyed sheet collides with the actuator, it is possible to reduce the load on the sheet with respect to the actuator, thereby effectively preventing inconvenience (for example, transfer deviation) due to the load. An object of the present invention is to provide a sheet conveying apparatus that can be used and an image forming apparatus including the sheet conveying apparatus.

  In order to solve the above-described problem, the sheet conveying apparatus according to the present invention is configured so that a sheet conveyed in a predetermined conveyance direction is in contact with an actuator that rotates about a rotation axis, thereby rotating the rotation axis. A sheet conveying device provided with a sheet detecting device that detects the sheet by rotating in a detection-side rotation direction that is a rotation direction toward a rotation detection side, wherein the actuator is applied to the conveyed sheet. In the posture when touching, the gravity center is located at a position other than the imaginary vertical line passing through the rotation axis, and the rotation direction is the rotation direction to the own weight side that rotates around the rotation axis by its own weight. Is configured in the same direction as the detection-side rotation direction.

  An image forming apparatus according to the present invention includes the sheet conveying apparatus according to the present invention.

  In the present invention, the actuator can be illustrated as being biased in a direction opposite to the rotation direction of the self-weight.

  In the present invention, the actuator includes an actuator main body and a protruding piece that protrudes from the actuator main body in a direction to contact the sheet conveyed, and the rotation axis contacts the sheet in the conveyance direction. The aspect which is set as the structure located upstream rather than the contact position with the said sheet | seat of the said protrusion piece when being done can be illustrated.

  In this invention, the said actuator can illustrate the aspect by which the said rotating shaft line is set as the structure located on the conveyance path | route of the said sheet | seat.

  In the present invention, the actuator has an angle formed between a virtual tangent of the rotation locus at the contact point of the rotation locus around the rotation axis of the projecting piece and the conveyance route and the conveyance route. The aspect made into the structure which is 90 degree | times or more can be illustrated.

  In this invention, the said actuator can illustrate the aspect by which the said rotation axis is set as the structure located in the protrusion side which the said protrusion piece protrudes from the said conveyance path rather than the conveyance path of the said sheet | seat.

  In the present invention, if an angle formed by a virtual straight line passing through the rotation axis of the actuator and a contact position of the protruding piece when the sheet is in contact with the sheet and the conveyance path is φ, The actuator can be exemplified by a configuration in which the rotation axis is located at a position satisfying a relationship of 0 degree <φ <45 degrees.

  In the present invention, a mode in which the actuator body and the protruding piece are integrally formed can be exemplified.

  In the present invention, an embodiment in which the actuator body and the protruding piece are detachably connected can be exemplified.

  In the present invention, it is possible to exemplify an aspect in which the protruding piece is connected to the actuator body so that the position around the rotation axis with respect to the actuator body can be adjusted.

  In the present invention, the actuator has a rotation fulcrum shaft that rotates about the rotation axis, and the rotation fulcrum shaft is positioned outside the sheet conveyance region in a direction along the rotation axis. The aspect which is doing can be illustrated.

  The image forming apparatus according to the present invention further includes a sheet passing portion through which the conveyed sheet passes, and the sheet detecting device is configured to detect the sheet in the middle of passing through the sheet passing portion. An aspect can be illustrated.

  Here, as the sheet passing portion, an image is transferred to an image influence portion that can affect an image due to a load on the actuator by the conveyed sheet, for example, a recording sheet that acts as the sheet in the image forming apparatus main body. Examples thereof include a transfer unit that performs image reading, and a document reading unit that reads an image of a document serving as the sheet in the image reading apparatus.

  According to the present invention, when the conveyed sheet collides with the actuator, it is possible to reduce the load on the sheet with respect to the actuator, thereby effectively preventing inconvenience (for example, transfer misalignment) due to the load. .

1 is a front view illustrating a schematic configuration of an image forming apparatus including a sheet conveying device according to an embodiment of the present invention. It is the schematic perspective view which looked at the sheet | seat detection apparatus and its peripheral part in the sheet conveying apparatus which concerns on 1st Embodiment from the diagonally right upper part of the front side. It is the schematic front view which looked at the sheet | seat detection apparatus shown in FIG. 2 from the front side. FIG. 3 is a schematic front view illustrating a detection state of the sheet detection apparatus illustrated in FIG. 2, and is a diagram illustrating a state at a time when a recording sheet comes into contact with an actuator. It is a schematic front view which shows the detection state of the sheet | seat detection apparatus shown in FIG. 2, Comprising: It is a figure which shows the state which the recording sheet passed the actuator and the actuator has act | operated the detection part. It is the schematic front view which looked at the sheet | seat detection apparatus which concerns on 2nd Embodiment from the front side. It is the schematic perspective view which looked at the turning shaft and the protrusion piece part in the sheet | seat detection apparatus which concerns on 3rd Embodiment from the diagonally right upper part of the front side. It is the schematic front view which looked at the conventional sheet detection apparatus from the front side. Changes in the load applied to the recording sheet from the time when the recording sheet comes into contact with the actuator in the conventional sheet detection device with respect to the conveyance distance of the recording sheet, and the recording sheet on the actuator in the sheet detection device according to the present embodiment 6 is a graph showing a change of a load applied to a recording sheet from a point of contact with respect to a conveyance distance at which the recording sheet is conveyed.

  Embodiments according to the present invention will be described below with reference to the drawings.

[Image forming apparatus]
FIG. 1 is a front view illustrating a schematic configuration of an image forming apparatus 1 including a sheet conveying device 30 according to an embodiment of the present invention. In FIG. 1 and FIGS. 2 to 8 to be described later, the symbol X indicates the width direction (depth direction), the symbol Y indicates the left-right direction Y orthogonal to the width direction X, and the symbol Z indicates The vertical direction (height direction) is shown.

  As shown in FIG. 1, the image forming apparatus 1 includes an image reading device 40 and an image forming device main body 10, and the image data read by the image reading device 40 or image data sent from an external device. Based on this, the image forming apparatus main body 10 forms a monochrome image or a color image on a recording sheet P such as recording paper.

  The image reading apparatus 40 includes a document conveying unit 41 and a document reading unit 42. The document reading unit 42 reads the document G conveyed by the document conveying unit 41 or the document G placed on the document placing table 42a. Is read by the original reading section 42, and the read image of the original G is output as image data.

  The image forming apparatus 1 is an electrophotographic image forming apparatus, and has a configuration in which a plurality of electrostatic latent image carriers (specifically, photoconductors) are arranged in parallel in a predetermined direction (in this example, the left-right direction Y), so-called. It is a tandem color image forming apparatus. In this example, the image forming apparatus 1 is an intermediate transfer type color composite machine capable of forming a full-color image. In this embodiment, the image forming apparatus 1 is a tandem type color image forming apparatus, but may be other color image forming apparatuses. Further, although the image forming apparatus 1 is a color image forming apparatus, it may be a monochrome image forming apparatus.

  The image forming apparatus main body 10 includes a photosensitive member 11 (specifically, a photosensitive drum) that functions as an image carrier, a charge eliminating device 12, a charger 13 that functions as a charging device, an exposure device 14, a developing device 15, and a primary transfer device. An intermediate transfer belt device 16, a drum cleaning device 17, a secondary transfer device 18, a belt cleaning device 19, a fixing device 20, a transport path R 1, a sheet transport device 30, a paper feed tray 31, and a discharge tray 32. .

  In the image forming apparatus main body 10, the surface of the photoconductor 11 is charged by the charger 13, and an image is exposed to the charged area to form an electrostatic latent image by the exposure device 14. The electrostatic latent image is developed by the developing device 15. Visualize (develop) the toner image as a toner image, electrostatically transfer the visualized toner image to the intermediate transfer belt device 16, and perform secondary transfer of the toner image transferred to the intermediate transfer belt device 16 The image is transferred to the recording sheet P by the device 18, and the toner image is fixed to the recording sheet P to which the toner image is transferred by the fixing device 20.

  The color image is formed by superimposing toner images of respective colors of black (K), cyan (C), magenta (M), and yellow (Y). For this reason, each of the photosensitive member 11, the static eliminating device 12, the charger 13, the developing device 15 and the drum cleaning device 17 is provided so as to form four types of toner images corresponding to the respective colors. Four image forming stations Pa, Pb, Pc, and Pd are configured in association with cyan, magenta, and yellow.

  In each of the image forming stations Pa, Pb, Pc, and Pd, the same operation as described below is performed.

  That is, the static eliminators 12 to 12 irradiate the surfaces of the photoreceptors 11 to 11 with light to remove (remove) charges on the surfaces of the photoreceptors 11 to 11.

  The chargers 13 to 13 uniformly charge the surfaces of the photoreceptors 11 to 11 that have been neutralized by the neutralization devices 12 to 12 to a predetermined potential.

  The exposure device 14 exposes the surfaces of the photoconductors 11 to 11 uniformly charged by the chargers 13 to 13 to form electrostatic latent images on the surfaces of the photoconductors 11 to 11.

  The developing devices 15 to 15 develop the electrostatic latent images on the surfaces of the photoconductors 11 to 11 formed by the exposure device 14 to form toner images on the surfaces of the photoconductors 11 to 11.

  In each of the image forming stations Pa, Pb, Pc, and Pd, a toner image of each color is formed on the surface of the photoreceptors 11 to 11 by such a series of operations.

  The intermediate transfer belt device 16 includes a primary transfer roller 16a, an intermediate transfer belt 16b, a transfer driving roller 16c, a transfer driven roller 16d, and a tension roller 16e. Four primary transfer rollers 16a are provided inside the intermediate transfer belt 16b, four by four, so as to form four types of toner images corresponding to each color. The primary transfer rollers 16a to 16a transfer the toner images of the respective colors formed on the surfaces of the photoconductors 11 to 11 to the intermediate transfer belt 16b that moves in the direction of arrow C. The intermediate transfer belt 16b is wound around a transfer driving roller 16c, a transfer driven roller 16d, and a tension roller 16e.

  The drum cleaning devices 17 to 17 remove and collect residual toner on the surfaces of the photoconductors 11 to 11 that remain without being transferred to the intermediate transfer belt 16b.

  The image forming apparatus 1 according to the present embodiment includes a sheet passage portion (transfer portion in this example) through which a conveyed sheet (recording sheet P in this example) passes. The sheet detection apparatus 300 is configured to detect a sheet (recording sheet P in this example) that is in the middle of passing through a sheet passing part (transfer unit in this example). Specifically, the sheet detection apparatus 300 is configured to detect the recording sheet P that is in the middle of passing through the transfer portion (specifically, the transfer nip region N). Specifically, the sheet detection apparatus 300 is on the conveyance path R1 in the vicinity (immediately downstream) of the transfer portion (specifically, the transfer nip area N) in the conveyance direction W of the recording sheet P (that is, downstream from the transfer nip area N). On the side of the transport path R1 with a shorter interval than the dimension in the transport direction W of the minimum size recording sheet P). The sheet detection apparatus 300 will be described in detail later.

  Here, the sheet passing portion is a transfer portion (specifically, a transfer nip area N) for transferring an image to the recording sheet P conveyed as a sheet in the image forming apparatus main body 10, but as a sheet in the image reading device 40. A document reading unit 42 that reads an image of the conveyed document G may be used. In this case, the sheet detection apparatus 300 is configured to detect the original G that is passing through the original reading unit 42.

  The secondary transfer device 18 includes a secondary transfer roller 18a. The secondary transfer roller 18a is provided so as to form a transfer portion (specifically, a transfer nip region N) between the intermediate transfer belt 16b and the transfer driving roller 16c. The secondary transfer roller 18a sandwiches and conveys the recording sheet P conveyed through the conveyance path R1, and transfers the recording sheet P to the transfer unit (specifically, the transfer nip region N). ), A toner image (for example, a color toner image) formed on the surface of the intermediate transfer belt 16b is transferred onto the recording sheet P. In this example, the transfer method of the image (specifically, the toner image) to the recording sheet P is a roller transfer method, but may be a corona transfer method.

  The belt cleaning device 19 removes and collects the residual toner remaining on the surface of the intermediate transfer belt 16b without being transferred to the recording sheet P.

  The fixing device 20 includes a heating roller 21 and a pressure roller 22. The recording sheet P onto which the toner image is transferred is sandwiched between the heating roller 21 and the pressure roller 22 to heat and press the toner image. To settle.

  The paper feed tray 31 is configured to stack the recording sheets P. A pickup roller 33 is provided on the supply side of the recording sheet P of the paper feed tray 31. The pickup roller 33 pulls out the recording sheet P from the paper feed tray 31 and transports it to the transport path R1.

  The sheet conveyance device 30 includes a conveyance path R1, a registration roller 34, conveyance rollers 35 to 35, a conveyance driving unit (not shown) that drives them, and a sheet detection device 300.

  The sheet conveyance device 30 conveys the recording sheet P to the discharge roller 36 via the secondary transfer device 18, the sheet detection device 300, and the fixing device 20 in the conveyance path R <b> 1. A discharge roller 36 is provided on the discharge side of the recording sheet P in the transport path R1. The discharge roller 36 discharges the recording sheet P conveyed on the conveyance path R <b> 1 to the discharge tray 32. In the transport path R1, a registration roller 34 and transport rollers 35 to 35 are provided. The registration roller 34 stops the recording sheet P at one end and aligns the leading end (downstream end in the transport direction W) of the recording sheet P, and then transfers the transfer portion (specifically, between the intermediate transfer belt 16b and the secondary transfer roller 18a). Specifically, the recording sheet P is conveyed in accordance with the transfer timing of the toner image in the transfer nip area N). Each of the conveyance rollers 35 to 35 is a roller that promotes conveyance of the recording sheet P.

  Further, the transport path R1 includes a reversing path Rr. When the image forming apparatus main body 10 forms an image not only on the front surface but also on the back surface of the recording sheet P, the recording sheet P is conveyed in the reverse direction from the discharge roller 36 to the reverse path Rr, so The toner image is reversed and guided again to the registration roller 34, and the toner image is fixed on the back surface of the recording sheet P in the same manner as the front surface of the recording sheet P and discharged to the discharge tray 32.

(About sheet detection device)
Next, the sheet detection apparatus 300 according to the present embodiment will be described below by taking as an example a case where the sheet detection apparatus 300 is applied to a conveyance sensor that detects the conveyance state of the recording sheet P such as the conveyance timing in the sheet conveyance apparatus 30 shown in FIG. .

(First embodiment)
FIG. 2 is a schematic perspective view of the sheet detection apparatus 300 and its peripheral portion in the sheet conveying apparatus 30 according to the first embodiment as viewed from the upper right side obliquely upward. FIG. 3 is a schematic front view of the sheet detection apparatus 300 shown in FIG. 2 as viewed from the front side. 4 and 5 are schematic front views showing a detection state of the sheet detection apparatus 300 shown in FIG. 4 is a diagram illustrating a state when the recording sheet P contacts the actuator 310, and FIG. 5 illustrates a state in which the recording sheet P passes through the actuator 310 and the actuator 310 operates the detection unit 320. FIG.

  2 to 5, the conveyance guide members and the like constituting the conveyance path R1 (see FIGS. 3 to 5) of the recording sheet P are not shown. 3 to 5, the frame side plates FL and FL (main body frame) and the urging members 330 and 330 shown in FIG. 2 are not shown.

  In the sheet detection apparatus 300 according to the first embodiment, the width direction X of the recording sheet P in which the sheet (in this example, the recording sheet P) conveyed in a predetermined conveyance direction W is orthogonal or substantially orthogonal to the conveyance direction W. Is rotated in a detection-side rotation direction V1, which is a rotation direction to the detection side around the rotation axis α, by contacting the actuator 310 that rotates about the rotation axis α along the recording sheet P. Is detected. In this example, the sheet detection apparatus 300 detects the conveyance timing of the recording sheet P conveyed in the conveyance direction W.

  The actuator 310 is in a position (virtual) other than on the virtual vertical line β (see FIG. 3) where the center of gravity Q (see FIG. 3) passes through the rotation axis α in the posture when it is in contact with the recording sheet P being conveyed. The self-weight side rotation direction V2 which is a rotation direction to the self-weight side which is located at any one side of the vertical line β and rotates around the rotation axis α by its own weight is the detection-side rotation direction. It is set as the structure which becomes the same direction as V1.

  Specifically, the sheet detection apparatus 300 includes an actuator 310 and a detection unit 320. The actuator 310 is supported by the image forming apparatus main body 10 (see FIG. 1) (in this example, the frame side plates FL and FL) (see FIG. 2) so as to be rotatable around the rotation axis α. The frame side plates FL, FL are provided on one side (front side) and the other side (back side) in the width direction X, and extend along both the left-right direction Y and the up-down direction Z.

  The actuator 310 includes a rotation fulcrum shaft 311 that rotates about the rotation axis α, and an actuator main body 312 that is fixed to the rotation fulcrum shaft 311 and rotates when the rotation fulcrum shaft 311 rotates about the rotation axis α. And a protruding piece 313 that protrudes from the actuator main body 312 in a direction in contact with the conveyed recording sheet P. Further, the actuator 310 is located upstream of the contact position 313a (see FIGS. 3 and 4) of the protruding piece 313 when the rotation axis α is contacted with the recording sheet P in the transport direction W. It is supposed to be configured.

  The rotation fulcrum shaft 311 includes a detection side rotation direction V1 around the rotation axis α and an opposite side rotation direction V3 opposite to the detection side rotation direction V1 (the rotation on the side where the actuator 310 contacts the recording sheet P). (Moving direction).

  In this example, the rotation fulcrum shaft 311 is located outside the conveyance area CA (see FIG. 2) of the recording sheet P in the direction along the rotation axis α (the width direction X in this example).

  Specifically, the rotation fulcrum shaft 311 is a pair of rotation fulcrum shafts 311 and 311 provided on one side (front side) and the other side (back side) on the outer side in the width direction X of the conveyance area CA of the recording sheet P. (See FIG. 2). The rotation fulcrum shafts 311 and 311 are columnar members whose length in the rotation axis α direction is about the diameter or slightly larger (by a predetermined length) than the diameter.

  Of the pair of rotation fulcrum shafts 311 and 311, the rotation fulcrum shaft 311 on one side (front side) is supported by the frame side plate FL on one side (front side) so as to be rotatable around the rotation axis α. A frame side plate FL on the other side (back side) is supported so as to be rotatable about a rotation axis α.

  The actuator main body 312 is configured to rotate about the rotation axis α as the rotation fulcrum shaft 311 rotates about the rotation axis α.

  The actuator body 312 includes a turning member 312a and a detected piece 312b.

  The turning member 312a is connected to the rotation fulcrum shaft 311 and has the protruding piece 313 fixed thereto. The detected piece 312b is fixed to the turning member 312a and turns by turning in the detection side turning direction V1 around the turning axis α of the turning fulcrum shaft 311 or in the opposite side turning direction V3. Activate or deactivate.

  Here, the detection-side rotation direction V1 is detected from a protruding position where the protruding piece 313 protrudes from the conveyance path R1 (see FIGS. 3 to 5) (specifically, a shielding position that blocks the conveyance path R1 of the recording sheet P). This is a direction toward the retracted position retracted toward the part 320, and the opposite side rotation direction V3 is a direction in which the protruding piece 313 is directed from the retracted position to the protruding position.

  Specifically, the turning member 312a includes a turning shaft 312a1 and a connecting member 312a2.

  The turning shaft 312a1 is a columnar member that is parallel or substantially parallel to the rotation axis α and whose length in the rotation axis α direction is larger than the size in the width direction X of the recording sheet P.

  The connecting member 312a2 connects the turning shaft 312a1 and the turning fulcrum shaft 311 so that the turning shaft 312a1 is displaced in a direction perpendicular to or substantially perpendicular to the turning axis α with respect to the turning fulcrum shaft 311. The connecting member 312a2 is a pair of connecting members 312a2 and 312a2 that are provided on both sides in the width direction X and are long in the displacement direction of the turning shaft 312a1 with respect to the turning fulcrum shaft 311.

  One side (front side) of the pair of connection members 312a2 and 312a2 is fixed to the inner end surface of the rotation fulcrum shaft 311 on one side (front side) of the outer surface of one end portion in the longitudinal direction. And the inner surface of the other end is fixed to one end surface (front-side end surface) of the turning shaft 312a1.

  Of the pair of connecting members 312a2 and 312a2, the other side (rear side) of the connecting member 312a2 (see FIG. 2) is the inner side of the rotation fulcrum shaft 311 whose outer surface at one end is the other side (rear side) in the longitudinal direction. It is fixed to the end surface, and the inner surface of the other end is fixed to the other end surface (rear side end surface) of the turning shaft 312a1.

  The protruding piece 313 is fixed to the turning shaft 312a1 and is in contact with the recording sheet P conveyed from the upstream side in the conveyance direction W (see FIGS. 4 and 5), so that the detection side rotation direction V1 around the rotation axis α. It is set as the structure which turns to.

  The actuator 310 is urged by a biasing member 330 (see FIG. 2) in a direction opposite to its own weight side rotation direction V2 (opposite side rotation direction V3). The sheet detection apparatus 300 further includes a biasing member 330 that biases the actuator 310 in a direction opposite to the self-weight side rotation direction V2.

  In the actuator 310, the protruding piece 313 is moved to the protruding position in the opposite rotation direction V <b> 3 against the own weight in the own weight side rotation direction V <b> 2 of the actuator 310 by the urging force of the urging member 330 in the opposite rotation direction V <b> 3. On the other hand, the recording sheet P being conveyed is rotated to the retracted position in the detection side rotation direction V1 against the urging force in the opposite rotation direction V3 of the urging member 330 by the conveyance force of the recording sheet P being conveyed. It is supposed to be.

  Specifically, the actuator 310 is configured such that the protruding piece 313 is positioned at the protruding position by the urging force of the urging member 330 when the recording sheet P is not conveyed (non-conveyed state). On the other hand, in the state where the recording sheet P is being conveyed (conveyed state), the actuator 310 is configured such that the protruding piece 313 is positioned at the retracted position against the urging force of the urging member 330 by the conveying force of the recording sheet P. It is said that. Further, the actuator 310 is configured such that after the recording sheet P passes, the protruding piece 313 returns to the protruding position by the urging force of the urging member 330.

  As shown in FIG. 2, the urging member 330 is a winding spring having a winding portion 331, one end portion 332, and the other end portion 333. The urging member 330 is a pair of urging members 330 and 330 provided on both sides (front side and back side) in the width direction X.

  Specifically, in the biasing member 330 on one side (front side) of the pair of biasing members 330, 330, the winding portion 331 is inserted through the rotation fulcrum shaft 311 on one side (front side), and one end portion. 332 is locked to the frame side plate FL on one side (front side), and the other end 333 is on one side (front side) of the actuator main body 312 (in this example, the connecting member 312a2 on one side (front side)). It is locked.

  In the biasing member 330 on the other side (back side) of the pair of biasing members 330, 330, the winding portion 331 is inserted through the rotation fulcrum shaft 311 on the other side (back side), and the one end portion 332 is The other side (back side) is locked to the frame side plate FL, and the other end 333 is locked to the other side (back side) of the actuator main body 312 (in this example, the other side (back side) connecting member 312a2). ing.

  While the detected piece 312b is fixed to the turning shaft 312a1 and turns in the same direction as turning to the detection side turning direction V1 around the turning axis α of the protruding piece 313, the detecting unit 320 is activated. It is set as the structure which turns in the same direction with the turning to the other side rotation direction V3 of the protrusion piece 313 around the rotation axis (alpha), and makes the detection part 320 non-operational.

  The detected piece 312b rotates in the detection-side rotation direction V1 to make the detection unit 320 inactive, while rotating in the opposite side rotation direction V3 to make the detection unit 320 in operation. It may be said.

  Specifically, the protruding piece 313 is located at a protruding position protruding toward the recording sheet P when the recording sheet P is not passing (see FIGS. 2, 3 and 4). At this time, the detected piece 312b is Then, the detection unit 320 is set to an operating state or a non-operating state (non-operating state in this example). On the other hand, when the recording sheet P is passing, the protruding piece 313 is positioned at a retracted position where the protruding sheet 313 is retracted from the protruding position (see FIG. 5). At this time, the detected piece 312b operates the detection unit 320 in the operating state or not. Set to the operating state (in this example, the operating state).

  In the actuator 310, the protruding piece 313 and the detected piece 312b are fixed at a position shifted by a predetermined angle in the direction around the rotation axis α with respect to the turning shaft 312a1.

  In this example, the actuator main body 312 and the protruding piece 313 are integrally formed. Specifically, the turning shaft 312a1 and the connecting member 312a2 are integrally formed to constitute the turning member 312a. Further, the turning member 312a and the detected piece 312b are integrally formed to constitute the actuator body 312. Specifically, the actuator 310 is formed of a resin material such as polycarbonate having high impact resistance and ABS resin (acrylonitrile, butadiene, styrene copolymer synthetic resin).

  The detection unit 320 is supported by a support member (specifically, a stay) (not shown). The support member is installed between the frame side plates FL, FL on one side (front side) and the other side (back side).

  The actuator body 312 further includes a restriction piece 312c that restricts further turning in the opposite rotation direction V3 around the rotation axis α from the protruding position of the protruding piece 313.

  Specifically, the restricting piece 312c is provided on the turning member 312a. In this example, the restricting piece 312c is fixed to the turning shaft 312a1. When the projecting position of the projecting piece 313 is regulated, the regulating piece 312c is brought into contact with the frame side plate FL (specifically, the regulating member FLa provided on the frame side plate FL on the other side (back side)). It has become.

  In the actuator 310, the regulating piece 312c and the protruding piece 313 are fixed at a position shifted by a predetermined angle in the direction around the rotation axis α with respect to the turning shaft 312a1. In the actuator 310, the regulating piece 312c and the detected piece 312b are fixed at a position shifted by a predetermined angle in the direction around the rotation axis α with respect to the turning shaft 312a1.

  In this example, the turning member 312a and the restriction piece 312c are integrally formed to constitute the actuator body 312.

  The actuator 310 is configured such that the rotation axis α is positioned on the conveyance path R1 of the recording sheet P (see FIGS. 3 to 5).

  Specifically, the actuator 310 has a contact S with the transport path R1 of the rotation locus γ (see FIGS. 4 and 5) around the rotation axis α of the downstream end 313b (see FIGS. 4 and 5) of the protruding piece 313. A configuration in which an angle θ (see FIGS. 4 and 5) formed by a virtual tangent δ (see FIGS. 4 and 5) of the rotation locus γ (see FIGS. 4 and 5) in the rotation path γ (see FIGS. 4 and 5) is 90 degrees or more. Has been.

  In this example, the conveyance path R1 for the recording sheet P is a conveyance path for conveying the recording sheet P obliquely upward.

  The detection unit 320 is a light transmissive photosensor having a light emitting unit 321 (see FIG. 2) that emits light and a light receiving unit 322 (see FIG. 3) that receives light from the light emitting unit 321.

  The detected piece 312b in the actuator 310 is configured to block or release the light between the light emitting unit 321 and the light receiving unit 322 by turning around the rotation axis α.

  Specifically, the light emitting unit 321 includes a light emitting element 321a (specifically, a light emitting diode) (see FIG. 2), and the light emitting element 321a is provided to face the light receiving unit 322 side. The light receiving unit 322 includes a light receiving element 322a (specifically, a photodiode) (see FIG. 2), and the light receiving element 322a is provided to face the light emitting element 321a in the light emitting unit 321.

(Second Embodiment)
FIG. 6 is a schematic front view of the sheet detection apparatus 300 according to the second embodiment as viewed from the front side. Note that in the second embodiment, identical symbols are assigned to configurations that are substantially similar to those in the first embodiment and descriptions thereof are omitted.

  In the sheet detection apparatus 300 according to the second embodiment, as shown in FIG. 6, the actuator 310 has the rotation axis α on the protruding side where the protruding piece 313 protrudes from the conveying path R1 rather than the conveying path R1 of the recording sheet P. It is supposed to be positioned.

  Specifically, the angle formed between the virtual straight line ε passing through the rotation axis α of the actuator 310 and the contact position 313a of the protruding piece 313 when contacting the recording sheet P and the conveyance path R1 is defined. Assuming φ, the actuator 310 is configured to be located at a position where the rotation axis α satisfies the relationship of 0 ° <φ <45 °.

(Third embodiment)
FIG. 7 is a schematic perspective view of the swivel shaft 312a1 and the protruding piece 313 in the sheet detection apparatus 300 according to the third embodiment as viewed from the upper right side of the front side. Note that in the third embodiment, identical symbols are assigned to configurations that are substantially similar to those of the first embodiment and descriptions thereof are omitted.

  In the sheet detection apparatus 300 according to the third embodiment, as shown in FIG. 7, the actuator main body 312 and the protruding piece 313 are detachably connected.

  Specifically, the protruding piece 313 is coupled to the actuator body 312 so that the position around the rotation axis α with respect to the actuator body 312 can be adjusted.

  Specifically, the turning member 312a further includes a support disk 312a3. The turning member 312a fixes the protruding piece 313 to the support disk 312a3 so that the position of the protruding piece 313 around the rotation axis α can be adjusted with respect to the turning axis 312a1. The support disk 312a3 is fixed on the same axis (rotation axis α) with respect to the turning shaft 312a1. The protruding piece 313 is provided with a through long hole 313c extending in an arc shape centering on the rotation axis α. The support disc 312a3 is provided with a fastening portion AP (screw hole in this example) that passes through the through long hole 313c and fastens a fixing member SC such as a screw (screw in this example). Thereby, the position around the rotation axis α of the protruding piece 313 with respect to the actuator main body 312 can be adjusted. The actuator body 312 is formed of a resin material having a relatively small specific gravity, such as polypropylene having a specific gravity of 0.90 to 0.91, polyethylene having a specific gravity of 0.91 to 0.965, and the like. The protruding piece 313 is made of polytetrafluoroethylene (PTFE) having a specific gravity of 2.14 to 2.2, precarbonate having a specific gravity of 1.2, and ABS resin having a specific gravity of 1.01 to 1.04 (both acrylonitrile, butadiene and styrene). Polymerized synthetic resin) or the like is formed of a resin material having a relatively large specific gravity.

  In this example, the protruding piece 313 is provided with a guide portion 313d that moves the protruding piece 313 in the direction around the rotation axis α. The guide portion 313d has a concave curved surface formed in accordance with the outer peripheral surface of the turning shaft 312a1 so that the protruding piece 313 is in sliding contact with the turning shaft 312a1 when the protruding piece 313 is adjusted with respect to the actuator body 312. doing. By doing so, it is possible to easily adjust the position of the protruding piece 313 around the rotation axis α with respect to the actuator body 312.

  The support disk 312a3 is provided with an adjustment scale GR indicating the position of the protruding piece 313 around the rotation axis α with respect to the actuator main body 312. In this way, the adjustment scale GR can be used as a guide for the amount of movement of the protruding piece 313 around the rotation axis α with respect to the actuator body 312, and thus the protruding piece 313 can be reliably adjusted with respect to the actuator body 312. It becomes possible to do.

(About this embodiment)
FIG. 8 is a schematic front view of a conventional sheet detection apparatus 300X viewed from the front side. In the conventional sheet detection apparatus 300X shown in FIG. 8, the same reference numerals are given to substantially the same configurations as those of the sheet detection apparatus 300 according to the present embodiment. In the actuator 310X, the protruding piece 313, the detected piece 312b, and the regulating piece 312c are fixed at a position shifted from the turning fulcrum shaft 311 by a predetermined angle in the direction around the turning axis α.

  By the way, the sheet conveyed in the predetermined conveyance direction W (the recording sheet P in this example) is brought into contact with the actuator 310X that rotates about the rotation axis α, so that the detection side about the rotation axis α is detected. Like the conventional sheet detection apparatus 300X (see FIG. 8) that rotates in the rotation direction V1 to detect the recording sheet P, the actuator 310X has a center of gravity in the posture when contacting the recording sheet P being conveyed. Q is located at a position other than on the virtual vertical line β passing through the rotation axis α (a position on either side of the virtual vertical line β), and is rotated around the rotation axis α by its own weight. If the self-weight side rotation direction V2 that is the rotation direction of the lens is opposite to the detection-side rotation direction V1, there are the following inconveniences.

  FIG. 9 shows changes in the load applied to the recording sheet P from the time when the recording sheet P contacts the actuator 310X in the conventional sheet detection apparatus 300X with respect to the conveyance distance in which the recording sheet P is conveyed, and the present embodiment. 6 is a graph showing a change of a load applied to the recording sheet P from a point in time when the actuator 310 in the sheet detecting apparatus 300 contacts with respect to a conveyance distance in which the recording sheet P is conveyed. In FIG. 9, reference symbol λa indicates a graph of the load characteristics on the recording sheet P with respect to the actuator 310X in the conventional sheet detection apparatus 300X. Reference numeral λb represents a graph of the load characteristic on the recording sheet P with respect to the actuator 310 in the sheet detection apparatus 300 according to the present embodiment. Reference numeral La indicates the position of the leading end of the recording sheet P when the recording sheet P starts to enter the actuator 310X in the conventional sheet detecting apparatus 300X and the sheet detecting apparatus 300 according to the present embodiment. Reference numeral Lb indicates the position of the leading edge of the recording sheet P when the center of gravity Q of the actuator 310X passes the virtual vertical line β by the conveyance force of the recording sheet P in the conventional sheet detection apparatus 300X. Reference numeral L denotes a moving region where the leading edge of the recording sheet P moves from the position La to the position Lb in the conventional sheet detection apparatus 300X.

  In the conventional sheet detection apparatus 300X, when the actuator 310X is in contact with the recording sheet P being conveyed, the actuator 310X has its own weight as a self-weight side rotation direction V2 around the rotation axis α due to its own weight. A force (F) (see FIGS. 8 and 9) that rotates in the direction opposite to the detection-side rotation direction V1 is applied (see the position La of the graph λa in FIG. 9). Accordingly, when the conveyed recording sheet P collides with the actuator 310X, a force F is applied to rotate the actuator 310X in the direction opposite to the detection-side rotation direction V1 around the rotation axis α due to its own weight. The load on the recording sheet P with respect to the actuator 310X becomes large (see the region L in the graph λa in FIG. 9), and the inconvenience due to the load is likely to occur.

  In this regard, according to the sheet detection apparatus 300 according to the present embodiment, the actuator 310 is on the virtual vertical line β in which the center of gravity Q passes through the rotation axis α in the posture when being in contact with the recording sheet P being conveyed. The self-weight-side rotation direction V2 that is located at a position other than that and rotates about the rotation axis α by its own weight is the same direction as the detection-side rotation direction V1.

  That is, in the posture of the actuator 310 when it is brought into contact with the recording sheet P being conveyed, the actuator 310 causes the actuator 310 to move by its own weight as the self-weight side rotation direction V2 around the rotation axis α, and the detection-side rotation direction V1. Force (−F) (see FIG. 3) is applied, and the recording sheet P is not affected by the weight of the actuator 310 when it contacts the actuator 310 (graph λb in FIG. 9). Position La). In this example, the actuator 310 has a force f (<F) that causes the actuator 310 to rotate in a direction opposite to the detection-side rotation direction V1 around the rotation axis α by the urging force of the urging member 330 (see FIG. 3). ) Only affected.

  That is, the actuator 310 is in the posture when the force f that rotates the actuator 310 in the direction opposite to the detection-side rotation direction V1 around the rotation axis α by the urging force of the urging member 330 is in contact with the sheet. The self-weight side rotation direction V2 is configured to be smaller than the force F when the detection-side rotation direction V1 is opposite to the detection-side rotation direction V1.

  Accordingly, when the conveyed recording sheet P collides with the actuator 310, the force F that causes the actuator 310 to rotate in the direction opposite to the detection-side rotation direction V1 around the rotation axis α due to its own weight is not applied. Thus, it is possible to reduce the load on the recording sheet P with respect to the actuator 310, thereby effectively preventing the occurrence of inconvenience due to the load.

  This is the case where the conveyance path R1 of the recording sheet P (the conveyance path R1 of the recording sheet P where the sheet detection device 300 detects the recording sheet P) is the conveyance path that conveys the recording sheet P obliquely upward. It is particularly effective.

  Further, since the actuator 310 is biased in the direction opposite to the self-weight side rotation direction V <b> 2, the leading edge of the recording sheet P comes into contact with the recording sheet P of the actuator 310 before entering the actuator 310. The position of the actuator 310 (specifically, the protruding position) can be maintained, and the attitude of the actuator 310 after the rear end (upstream end in the transport direction) of the recording sheet P passes through the actuator 310 is set to the recording sheet P. It is possible to automatically return to the abutting posture (specifically, the protruding position).

  The actuator 310 includes an actuator main body 312 and a projecting piece 313 that protrudes from the actuator main body 312 in a direction in contact with the recording sheet P being conveyed. Since the protruding piece 313 is positioned upstream of the contact position 313a of the protruding piece 313 with the recording sheet P, the self-weight side rotation direction V2 is the same as the detection-side rotation direction V1. The configuration of the actuator 310 can be easily realized.

  In the first embodiment, the actuator 310 is configured such that the rotation axis α is positioned on the conveyance path R1 of the recording sheet P, so that the self-weight side rotation direction V2 is the detection side rotation direction V1. The configuration of the actuator 310 in the same direction can be easily realized.

  In the first embodiment, the actuator 310 conveys the virtual tangent δ of the rotation locus γ at the contact point S with the conveyance path R1 of the rotation locus γ around the rotation axis α of the downstream end 313b of the protruding piece 313. Since the angle θ formed with the path R1 is 90 degrees or more, the rotation range of the actuator 310 that is rotated by the conveyance of the recording sheet P can be reduced, and the recording sheet with respect to the actuator 310 is correspondingly reduced. The load on P can be reduced, and thereby the occurrence of inconvenience due to the load can be more effectively prevented.

  In the second embodiment, the actuator 310 is configured such that the rotation axis α is positioned on the protruding side where the protruding piece 313 protrudes from the conveying path R1 with respect to the conveying path R1 of the recording sheet P. The configuration of the actuator 310 in which the side rotation direction V2 is the same as the detection side rotation direction V1 can be further easily realized.

  In the second embodiment, if the angle formed by the virtual straight line ε passing through the rotation axis α of the actuator 310 and the contact position 313a and the transport path R1 is φ, the actuator 310 has a rotation axis α of 0 degree. The configuration of the sheet detection apparatus 300 can be made compact by being configured to be located at a position satisfying the relationship of <φ <45 degrees.

  Moreover, in embodiment except 3rd Embodiment, since the actuator main body 312 and the protrusion piece 313 are integrally formed, the shaping | molding of the actuator main body 312 and the protrusion piece 313 can be made easy, In addition, the dimensional accuracy can be improved.

  Further, in the embodiment including the third embodiment, the actuator body 312 and the protruding piece 313 are detachably connected, so that the protruding piece 313 is made of a material having a higher specific gravity than the actuator body 312. Accordingly, the degree of freedom in designing the actuator 310 when the self-weight side rotation direction V2 is set in the same direction as the detection side rotation direction V1 can be improved.

  In the embodiment including the third embodiment, the protruding piece 313 is connected to the actuator main body 312 so that the position around the rotation axis α with respect to the actuator main body 312 can be adjusted. The position around the rotation axis α with respect to 312 can be easily adjusted.

  By the way, when the actuator 310 has a rotation fulcrum shaft 311 that rotates about the rotation axis α, and the rotation fulcrum shaft 311 is installed on or near the conveyance path R1 of the recording sheet P, The rotation fulcrum shaft 311 obstructs conveyance of the recording sheet P on the conveyance path R1, and hinders conveyance of the recording sheet P.

  In this regard, in the present embodiment, the actuator 310 has a rotation fulcrum shaft 311 that rotates about the rotation axis α, and the rotation fulcrum shaft 311 has the recording sheet P in the direction along the rotation axis α. The rotation fulcrum shaft 311 can be prevented from interfering with the conveyance path R1 of the recording sheet P by being located outside the conveyance area CA.

  In the present exemplary embodiment, the image forming apparatus 1 also includes a sheet passing portion (for example, a transfer portion or a document reading portion, which is a recording sheet P or a document G, in this example, a recording sheet P). In the example, the sheet detection device 300 is configured to detect a sheet in the middle of passing through the sheet passing portion, so that an image due to a load on the actuator 310 by the conveyed sheet is applied to the image. The influence can be suppressed. For example, as in the first to third embodiments, when the sheet passing unit is a transfer unit that transfers an image to the recording sheet P that acts as a sheet, the sheet detection apparatus 300 includes a transfer unit (specifically, Is configured to detect the recording sheet P in the middle of passing through the transfer nip area N). However, even if the conveyed recording sheet P enters the actuator 310, the brake applied to the recording sheet P by the impact is applied. Accordingly, it is possible to reduce the occurrence of image defects (so-called transfer misalignment) in which the transfer image is shifted in the transport direction W.

  In the present exemplary embodiment, the sheet detection apparatus 300 is configured to detect the recording sheet P in the middle of the image forming apparatus main body 10 passing through the transfer portion (specifically, the transfer nip area N). The image reading apparatus 40 may be configured to detect the original G that is passing through the original reading unit 42.

  The present invention is not limited to the embodiment described above, and can be implemented in various other forms. Therefore, such an embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image forming apparatus main body 18 Secondary transfer apparatus 18a Secondary transfer roller 30 Sheet conveying apparatus 300 Sheet detecting apparatus 300X Sheet detecting apparatus 310 Actuator 310X Actuator 311 Rotating fulcrum shaft 312 Actuator main body 312a Rotating member 312a1 Rotating shaft 312a2 Connecting member 312a3 Support disk 312b Detected piece 312c Restricting piece 313 Protruding piece 313a Abutting position 313b Downstream end 313c Through hole 313d Guide portion 320 Detecting portion 321 Light emitting portion 321a Light emitting device 322 Light receiving portion 322a Light receiving device 330 Energizing member 331 Winding portion 332 One end portion 333 Other end portion 40 Image reading device 42 Document reading portion AP Fastening portion CA Conveyance area FL Frame side plate FLa Restricting member G Document GR Adjustment scale L Area N Transfer nip area P Recording sheet Q Heavy Center R1 Transport path S Contact SC Fixed member V1 Detection side rotation direction V2 Self-weight side rotation direction V3 Opposite side rotation direction W Transport direction X Width direction Y Left and right direction Z Vertical direction α Rotation axis β Virtual vertical line γ Rotation Trajectory δ Virtual tangent ε Virtual straight line θ Angle formed by virtual tangent and transport path Angle formed by virtual straight line and transport path

Claims (14)

A sheet conveyed in a predetermined predetermined conveyance direction is brought into contact with an actuator that rotates about a rotation axis, thereby causing the detection side rotation direction that is a rotation direction to the detection side about the rotation axis. A sheet conveying device provided with a sheet detecting device that rotates to detect the sheet,
The actuator is positioned at a position other than on a virtual vertical line passing through the rotation axis in a posture when the actuator is in contact with the conveyed sheet, and rotates toward the own weight by its own weight. The sheet conveyance device is characterized in that the rotation direction of its own weight is the same direction as the rotation direction of the detection side. The sheet conveying apparatus according to claim 1,
The sheet conveying apparatus according to claim 1, wherein the actuator is biased in a direction opposite to the rotation direction of the own weight. The sheet conveying apparatus according to claim 1 or 2, wherein
The actuator includes an actuator main body and a protruding piece that protrudes from the actuator main body in a direction in contact with the conveyed sheet, and the rotation axis is in contact with the sheet in the conveying direction. A sheet conveying apparatus, characterized in that the protruding piece is positioned upstream of a contact position of the protruding piece with the sheet. The sheet conveying apparatus according to claim 3,
The sheet conveying apparatus according to claim 1, wherein the actuator is configured such that the rotation axis is positioned on a conveying path of the sheet. The sheet conveying apparatus according to claim 4,
In the actuator, an angle formed by a virtual tangent of the rotation locus at the contact point of the rotation locus around the rotation axis of the downstream end of the projecting piece and the conveyance route is 90 degrees or more. A sheet conveying apparatus having a certain configuration. The sheet conveying apparatus according to claim 3,
The sheet conveying apparatus according to claim 1, wherein the actuator is configured such that the rotation axis is positioned on a protruding side where the protruding piece protrudes from the conveying path with respect to the conveying path of the sheet. The sheet conveying device according to claim 6,
When an angle formed between a virtual straight line passing through the rotation axis of the actuator and the contact position of the protruding piece when the contact is made with the sheet and the transport path is φ,
The sheet conveying apparatus according to claim 1, wherein the actuator is configured such that the rotation axis is located at a position satisfying a relationship of 0 degree <φ <45 degrees. A sheet conveying apparatus according to any one of claims 3 to 7,
The sheet conveying apparatus, wherein the actuator body and the protruding piece are integrally formed. A sheet conveying apparatus according to any one of claims 3 to 7,
The sheet conveying apparatus, wherein the actuator body and the protruding piece are detachably connected. The sheet conveying device according to claim 9,
The sheet conveying apparatus, wherein the protruding piece is connected to the actuator body so that a position around the rotation axis with respect to the actuator body can be adjusted. A sheet conveying apparatus according to any one of claims 1 to 10, wherein
The actuator has a rotation fulcrum shaft that rotates around the rotation axis,
The sheet conveyance device, wherein the rotation fulcrum shaft is located outside a conveyance region of the sheet in a direction along the rotation axis.   An image forming apparatus comprising the sheet conveying device according to any one of claims 1 to 11. The image forming apparatus according to claim 12,
A sheet passing portion through which the conveyed sheet passes,
The image forming apparatus, wherein the sheet detection device is configured to detect the sheet in the middle of passing through the sheet passage portion. The image forming apparatus according to claim 13,
The image forming apparatus, wherein the sheet passing section is a transfer section that transfers an image to a recording sheet that acts as the sheet.

Images