JP2012025535A - Sheet conveying device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device that has a simple configuration for holding, in place of a delivery tray, a plurality of sheets and also shortening the processing time.SOLUTION: The sheet conveying device includes: a conveying roller pair comprising a driving roller 50 and a driven roller 51 which is in pressure contact with the driving roller for rotation, wherein the driving roller 50 and the driven roller 51 form a nip to hold and convey a sheet; a conveyance resistance member 54 configured to abut on one of the sheet ends in the width direction of the sheet which is held and conveyed by the conveying roller pair and apply conveyance resistance to the sheet. The driving roller 50 starts rotating so that the sheet approaches the nip. The sheet is held by the conveying roller pair 50, 51 and conveyed in the conveying direction and, at the same time, toward the conveyance resistance member 54. The driving roller 50 stops while the one end of the sheet held by the conveying roller pair 50, 51 is in abutment with the conveyance resistance member 54, which is repeated for every sheet. The sheet is held by the conveying roller pair 50, 51 and the conveyance resistance members 54.

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet and an image forming apparatus including the same, such as a copying machine and a laser printer.

  In the conventional image forming apparatus, after the image is fixed through an image forming process, the sheet is discharged and stacked on a discharge tray by a pair of discharge rollers. As a form of the discharge tray, there are a method of providing a discharge tray in the upper part of the apparatus, a method of providing a discharge port on the side of the apparatus, and a method of attaching the discharge tray by protruding from the apparatus main body. In particular, when the discharge tray protrudes from the apparatus main body, the discharge tray is folded and stored in the apparatus main body, or is attached to the apparatus main body as a separate part from the apparatus main body. However, in this configuration, it is necessary to pull out a discharge tray stored during installation or use of the apparatus or attach a discharge tray as a separate part.

  On the other hand, a configuration in which the above-described discharge tray is eliminated from the image forming apparatus is disclosed. For example, a configuration shown in FIG. 11 is disclosed (see Patent Document 1). In FIG. 11, 104 is a sheet, 101 is a sheet detector for detecting the presence or absence of the sheet 104, 102 is a discharge roller for nipping and conveying the sheet 104, and 103 is an opening (discharge port) provided in the apparatus main body. . When the sheet detector 101 detects the leading edge of the sheet 104 conveyed in the direction of arrow J in the figure, the discharge roller 102 and the image forming operation are stopped after a certain time. As a result, the sheet 104 is held with its rear end held between the discharge rollers 102 and with its front end suspended from the opening 103. Next, when the sheet 104 held by the discharge roller 102 is pulled and taken out, the sheet detector 101 is turned off, and the next image forming operation is automatically started. By repeating this sequentially, it is possible to eliminate a discharge tray for stacking discharged sheets.

  For example, a configuration shown in FIG. 12 is disclosed (see Patent Document 2). FIG. 12 shows a guide part 121 that guides the sheet 114 conveyed in the direction of the arrow K in the drawing from the apparatus main body side, and a stacker part 115 that sandwiches and holds the sheet 114. The guide unit 121 includes a relay roller 117 and a pressure roller 119 that sandwich and convey the sheet 114, and a guide plate 116 that guides the sheet 114. The stacker unit 115 includes a stopper unit 110 that abuts the sheet 114, gripper rollers 111 a and 111 b that send the sheet 114 to the stopper unit 110, and a guide plate 112 that guides the sheet 114 to the stopper unit 110. The gripper rollers 111 a and 111 b are configured to idle when the sheet 114 hits the stopper portion 110.

  The sheet 114 conveyed from the apparatus main body side in the direction of arrow K in the drawing passes through the guide portion 121 and hits the stopper portion 110 by the gripper rollers 111a and 111b to form a loop as shown by a broken line in the drawing. The formed loop gradually grows by the relay roller 117, and when the trailing end of the sheet 114 passes through the relay roller 117, the sheet 114 is sandwiched between the gripper rollers 111a and 111b, and the trailing end is below the stacker unit 115. It is held in a hung state. When the next sheet is transported in this state, the sheet transported from the direction of arrow K in the drawing is transported by the relay roller 117 and is held by the stopper portion 110 via the idler gripper rollers 111a and 111b. By repeating this, a plurality of sheets can be held and the discharge tray can be eliminated.

JP 05-188680 A JP 05-43116 A

  However, in the configuration shown in FIG. 11, the next sheet conveying operation is started only after the user pulls out the sheet 104 from the discharge roller 102 and the sheet detector 101 is turned off. Can not. In addition, when a plurality of image forming processes are performed, the next process is not performed unless the user pulls out the sheet from the apparatus main body. Therefore, the user needs to discharge each sheet until the plurality of image forming processes are completed. Yes, the process takes time.

  In the configuration shown in FIG. 12, a plurality of sheets can be held. However, since a stacker unit including a stopper unit, a pair of clipper rollers, and a guide plate is necessary, the apparatus configuration is complicated. In addition, since the sheet being conveyed is abutted against the stopper portion and sandwiched between the pair of clipper rollers, a loop is formed, so that the interval between the sheets to be sequentially conveyed needs to be controlled with a margin, This process takes time.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveying apparatus capable of holding a plurality of sheets with a simple configuration and shortening processing time instead of a discharge tray for stacking discharged sheets.

  In order to achieve the above object, the present invention provides a driving roller that conveys a sheet in the conveying direction to one side in a width direction orthogonal to the conveying direction, a driven roller that is pressed against the driving roller and is driven to rotate. A pair of conveying rollers that form a nip portion and nipping and conveying the sheet, and one end in the width direction of the sheet nipped and conveyed by the pair of conveying rollers, thereby conveying resistance to the sheet Conveying resistance means for applying, and starting the rotation of the driving roller to cause the guided sheet to enter the nip portion, and sandwiching the sheet by the conveying roller pair and conveying the sheet in the conveying direction. The operation of stopping the driving roller is guided in a state where the sheet is conveyed toward the resistance means and the one end of the sheet held by the pair of conveyance rollers is in contact with the conveyance resistance means. Repeat for each over preparative, characterized by holding the sheet by the conveying roller pair and the conveyance resistance means.

  According to the present invention, instead of a tray for stacking discharged sheets, a plurality of sheets can be held with a simple configuration using a pair of conveyance rollers and conveyance resistance means, and a tray protruding from the image forming apparatus is provided. It can be lost. Further, since the sheet can be held only by abutting the width direction end of the sheet to be conveyed while being sandwiched and conveyed by the conveyance roller pair, the processing time can be shortened as compared with the conventional configuration.

Sectional drawing of the image forming apparatus provided with the sheet conveying apparatus which concerns on 1st Embodiment Top view of the sheet conveying apparatus according to the first embodiment Schematic sectional view showing the first sheet conveyance state in the first embodiment Schematic sectional view showing the second sheet conveyance state in the first embodiment Schematic sectional view showing the third sheet conveyance state in the first embodiment Top view of a sheet conveying apparatus according to the second embodiment Top view of a sheet conveying apparatus according to the third embodiment Top view of a sheet conveying apparatus according to the fourth embodiment Top view of a sheet conveying apparatus according to a fifth embodiment Top view of a sheet conveying apparatus according to a fifth embodiment Explanatory drawing of the sheet conveying apparatus according to the prior art Explanatory drawing of the sheet conveying apparatus according to the prior art

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

[First Embodiment]
An image forming apparatus having a sheet conveying apparatus according to the first embodiment will be described. In the following description, a laser beam printer will be described as an example of an image forming apparatus. FIG. 1 is a schematic explanatory diagram of an image forming apparatus having a sheet conveying device. 2 is an explanatory diagram of the sheet conveying apparatus according to the first embodiment, FIG. 3 is an explanatory diagram of the first sheet conveyance state, FIG. 4 is an explanatory diagram of the second sheet conveyance state, and FIG. These are explanatory drawings of the third sheet conveyance state.

(Configuration of image forming apparatus)
In FIG. 1, the image forming apparatus 90 includes a sheet cassette 91, a feeding roller 92, a registration roller 93, and a conveying roller 94. Further, a process cartridge 97, a transfer roller 96, an optical unit 98, and a fixing device 99, which integrally have a photosensitive drum 95 and process means acting thereon as an image carrier, are provided. Further, a sheet conveying device described later is provided.

  The operation of the image forming apparatus 90 having this configuration will be described. The sheets S stacked in the sheet cassette 91 are fed by a feeding roller 92 and conveyed to a registration roller 93 through a conveying roller 94.

  On the other hand, in the image forming unit, the optical unit 98 exposes and scans the surface of the photosensitive drum 95 included in the process cartridge 97 with a laser beam to form a latent image. To this latent image, toner is supplied from a developing device (not shown) included in the process cartridge 97, and a toner image is formed on the photosensitive drum 95.

  The sheet S transported to the registration roller 93 is synchronized with the transfer roller 96 and the photosensitive drum 95 by the registration roller 93 in synchronization with the above-described exposure scanning so that the toner image is transferred to a predetermined position on the sheet S. It is conveyed to the transfer nip portion to be formed. The toner image formed on the photosensitive drum 95 is transferred onto the sheet S by the transfer roller 96.

  The sheet S to which the toner image has been transferred is conveyed to a fixing device 99 where heat and pressure are applied to the toner, and the toner is melted and fixed on the sheet S. After fixing, the sheet S passes through the conveying rollers 94 and 100 and is conveyed out of the apparatus from the discharge port (opening) 57 by a sheet conveying apparatus described below.

(Configuration of sheet conveying device)
FIG. 2 is a top view illustrating the sheet conveying apparatus. A pair of conveyance rollers 50 and 51 capable of holding sheets in a stacked manner are disposed upstream of the discharge port 57 in the sheet conveyance direction (the direction of arrow P). One of the conveying roller pairs 50 and 51 is composed of a driving roller 50 that is driven and rotated, and the other is a driven roller 51 that is driven and rotated. A sheet conveyance direction end detection sensor 55 is disposed above the sheet upstream in the sheet conveyance direction from the pair of conveyance rollers 50 and 51. The sheet conveyance direction end detection sensor 55 detects the position of the sheet in the conveyance direction in order to control the timing of starting and stopping the rotation of the driving roller 50 by a control unit (not shown) included in the image forming apparatus main body. It is a conveyance direction position detection means. Further, a guide 56 that guides the sheet S to the conveyance roller pair 50, 51 is attached upstream in the vicinity of the conveyance roller pair 50, 51.

  The guide 56 that guides the sheet S to the pair of conveying rollers 50 and 51 is a guide member that guides the leading end of the sheet S from the nip portion of the pair of conveying rollers 50 and 51 toward the driving roller 50. The conveyance roller 100 conveys the sheet conveyed from the fixing device 99 upward, above the guide 56, and follows the uppermost sheet held in the nip portion of the conveyance roller pair 50, 51. It is arranged and shaped so that it is piled up. For example, the uppermost position held in the nip portion of the pair of conveyance rollers 50 and 51 with a difference in height between the nip position of the conveyance roller 100 and the guide surface of the guide 56 is not limited to the configuration in which the nip angle of the conveyance roller 100 is upward. Subsequent sheets may be stacked on the other sheet. With such a configuration, the subsequent sheet is superimposed on the upper surface of the sheet held by the conveyance roller 100 and guided so as to come into contact with the peripheral surface of the driving roller 50.

  The driven roller 51 is pressed against the driving roller 50 with a pressing force N to form a nip portion of the pair of conveying rollers 50 and 51.

  The driving roller 50 and the driven roller 51 are provided so as to intersect at an intersection angle θ. Here, the axis of the driven roller 51 is orthogonal to the direction of the arrow P, which is the sheet conveyance direction, and the axis of the driving roller 50 intersects the axis of the driven roller 51 at an angle θ. Since the axis of the drive roller 50 is thus inclined with respect to the sheet conveyance direction, the conveyance roller pair 50, 51 is configured to convey the sheet S in the conveyance direction (arrow P direction) in the width direction orthogonal to the conveyance direction. It is configured to carry (slope feed) one side (in the direction of arrow C). A gear 52 is attached to the shaft of the driving roller 50, and is rotated in the direction of an arrow A for conveying a sheet as a result of driving transmission from a driving source (not shown). On the shaft of the driven roller 51, there is provided a torque limiter 53 as a brake means having the other end fixed so that a brake (load) is applied in a direction (arrow B direction) opposite to the sheet conveying direction (arrow P direction). .

Further, on the downstream side of the pair of conveyance rollers 50 and 51, a conveyance resistance member 54 formed of, for example, rubber or the like, which is in contact with one end portion in the width direction orthogonal to the conveyance direction of the sheet S and serves as conveyance resistance is disposed. ing. In addition, the conveyance resistance member 54 as a conveyance resistance means is not limited to the downstream side of the conveyance roller pair 50, 51, and may be disposed on the upstream side. In FIG direction of arrow C, the initial position of the one end portion of the front sheet the sheet S is conveyed by the nip portion of the pair of conveying rollers 50 and 51 When Y _0, the conveying resistance member 54 from the initial position Y ₀ given distance Y ₁ away are arranged. As will be described later, when the conveyance distance for conveying the sheet S in the direction of arrow P by the conveyance roller pairs 50 and 51 is X ₀ (see FIG. 3), the sheet S is conveyed so as to contact the conveyance resistance member 54. of the conveying distance Y ₁ in the arrow C direction of the sheet S has become the relation of the following formula (1).

| Y ₁ −Y ₀ | <X ₀ · tan θ (1)

  As a result, the sheet S is conveyed in the direction of the arrow C while being conveyed in the direction of the arrow P at the nip portion of the conveyance roller pair 50 and 51 in the direction of the arrow P, and is conveyed obliquely. Will come into contact.

FIG. 3 shows a dynamic model when the first sheet is conveyed by the sheet conveying apparatus. When the first sheet and the sheet S _1, the sheet S ₁ conveyed from the fixing device is guided to the nip portion of the pair of conveying rollers 50 and 51 by the guide 56 passes through the sheet conveyance direction end portion detection sensor 55 . The sheet conveyance direction end detection sensor 55 detects the leading edge of the sheet S ₁ , and after a predetermined time has elapsed, the drive is transmitted to the drive roller 50 immediately before the sheet S ₁ contacts the drive roller 50. The rotation starts in the direction of arrow A in the figure. In this case, the sheet S _1, the conveying force from the surface friction coefficient mu ₁ and the driven roller 51 of the drive roller 50 on the sheet S ₁ to the conveying direction consists of the product of the normal force N which sheet S ₁ is subjected (arrow P) μ ₁ N works. At the same time, the sheet S _1, acting through the driven roller 51 from the torque limiter 53, the brake force (load on conveying force mu _{1 N)} in the conveying direction (arrow P) and reverse direction (arrow B direction) F ₁ works. In order to sheet S ₁ is conveyed in the conveying direction (arrow P), it is necessary that the relationship between conveying force mu _{1 N} and the brake force is the following formula (2). Here, the vertical drag N that the sheet S receives from the driven roller 51 is the pressing force N of the driven roller 51 against the driving roller 50 described above.

μ ₁ N> F ₁ (2)

On the other hand, when the drive roller 50 is driven, the load F ₁ described above from the sheet S ₁ and the set torque Tr of the torque limiter 53 act on the driven roller 51. When the radius R of the driven roller 51, driven roller 51 is required relationship of the following formula (3) in order to rotationally driven in the conveying direction (arrow P) so as to convey the sheet S _1.

F ₁ R ≧ Tr (3)

Accordingly, the set value Tr of the torque limiter 53 for conveying the sheet S ₁ is set to be the following formula (4) from the above formulas (2) and (3).

μ ₁ N> Tr / R (4)

Sheet _{S 1} is by stopping the driving roller 50 while passing through the nip portion of the pair of conveying rollers 50, 51 holds the sheet _{S 1} to the nip of the conveying roller pair 50 and 51. At this time, the sheet S ₁ is conveyed by the arrow P direction by a predetermined distance X ₀ from the nip center of the conveying roller pairs 50 and 51. Further, the end of the sheet S ₁ is conveyed in the direction of arrow C in FIG. 2 by a predetermined distance Y ₁ from the initial position Y ₀ , and the end contacts the conveyance resistance member 54 from the relationship of the above-described formula (1). is doing.

Next, FIG. 4 shows a dynamic model when the second sheet is conveyed by the sheet conveying apparatus. When the second sheet and the sheet _{S 2,} the sheet _{S 2} is conveyed to the nip portion of the conveyance in the same manner as the sheet _{S 1} roller pair 50, 51. With only the sheet S ₁ is held in the nip of the conveying roller pair 50 and 51, if the resistance force from the conveyance resistance member 54 on the sheet S ₁ and F _5, since the resistance force F ₅ is a very small force The following formula (5) is satisfied.

μ ₁ N> Tr / R + F ₅ (5)

Next, the subsequent sheet S2 is detected by the detection sensor 55, and the driving roller 50 rotates after a predetermined time. Then, the resistance force F from the conveyance resistance member 54 is applied to the sheet S ₁ held in the nip portion of the conveyance roller pair 50, 51 until the subsequent sheet S ₂ enters the nip portion of the conveyance roller pair 50, 51. _A conveyance force μ ₁ N greater than _{5 is applied} from the drive roller 50. Therefore, the sheet S ₁ resists the resistance force F ₅ until the subsequent sheet S ₂ enters the nip portion of the conveyance roller pair 50 and 51 and the conveyance force μ ₁ N from the driving roller 50 is interrupted. is a predetermined distance X ₁ conveying direction of arrow P Te.

When the sheet _{S 2} rushes into nip portion of the conveying roller pairs 50 and 51, the sheet _{S 2,} it acts conveying force mu ₁ N in the transport direction (arrow P) from the drive roller 50. If the surface friction coefficient between sheets is μ ₂ , a force μ ₂ N acts from the sheet S _{1 in the} opposite direction (arrow B direction) to the conveyance direction (arrow P direction). In order to sheet S ₂ is inclined feeding is conveyed into 2 in the direction of the arrow C while being conveyed in the arrow direction P, it is necessary that the relationship of the conveying force is the following formula (6) .

μ ₁ N> μ ₂ N (6)

Further, the sheet _{S 1,} the sheet _S 1, the conveying force mu ₂ N from the friction coefficient mu ₂ between _{S 2} in the transport direction P generated works. At the same time, the brake force (load against the conveyance force μ ₂ N) F _{2 in the} opposite direction (arrow B direction) acting from the torque limiter 53 via the driven roller 51, and the conveyance resistance member 54 and the resistance force F ₅ from the works. In order to sheet S ₁ when the seat S ₂ has entered the nip of the conveying roller pair 50 and 51 is stopped, the conveying force mu ₂ N and the brake force F ₂ and the conveyance resistance force F ₅ The relationship needs to be the following formula (7).

F ₂ + F ₅ ≧ μ ₂ N (7)

On the other hand, in order to also stop the driven roller 51, it is necessary that the relationship of R, F ₂ , and Tr described above is expressed by the following formula (8).

Tr ≧ F ₂ R (8)

Because the resistance force F ₅ is a very small force, the setting value Tr of the torque limiter 53 the equation (7), are set so that the following equation (9) (8).

Tr / R ≧ μ ₂ N (9)

  Thereby, the set value Tr of the torque limiter 53 is set to the following formula (10) by the above formulas (4) and (9).

μ ₁ N> Tr / R ≧ μ ₂ N (10)

After the sheet S ₂ is conveyed by a predetermined distance X ₀ , the driving roller 50 is stopped, and both the sheet S ₁ and the sheet S ₂ are held at the nip portion of the conveying roller pair 50, 51.

Next, FIG. 5 shows a dynamic model when the third sheet is conveyed by the sheet conveying apparatus. Assuming that the third sheet is the sheet S ₃ , the sheet S ₃ is conveyed to the nip portion of the conveying roller pair 50 and 51 in the same manner as the sheet S ₂ . At this time, the sheet S ₂ which is held prior to the nip portion of the conveying roller pair 50, 51 in the drawing until the sheet S ₃ conveyed thereafter enters the nip portion of the conveying roller pairs 50 and 51 It is conveyed by the predetermined distance X ₁ to the arrow P direction. Further, the sheet S ₂ is conveyed while the sheet edge to the conveyance resistance member 54 is in contact. Accordingly, the leading ends of the sheet S ₂ and the sheet S ₁ are aligned at the position of | X ₀ + X ₁ | from the center of the nip portion of the pair of conveying rollers 50 and 51 in the direction of the arrow P in the drawing.

When the sheet _{S 3} is conveyed to the nip portion of the conveying roller pair 50 and 51, for the same reasons as when the second sheet transport, the sheet _{S 3,} the sheet _{S 2,} respectively between the sheet _{S 1} friction _mu 2 N The frictional force μ ₂ N causes the driven roller 51 to generate the conveying force F ₂ via the sheet S ₁ . At this time, the sheet S ₃ is similarly to the second sheet transport, the above equation (6), while being conveyed into the in the arrow direction P is conveyed to the 2 in the direction of the arrow C is skew. Similarly, the sheet _{S 1} is stopped by the above formula (7).

The sheet S ₂ is sandwiched between the sheet S ₁ and the sheet S ₃ at the nip portion of the pair of conveyance rollers 50 and 51, and an end portion thereof is in contact with the conveyance resistance member 54. Therefore, resistance force from the sheet _{S 3} than the conveying direction (arrow P direction) _mu 2 N, backward from the sheet _{S 1} is stopped (arrow B direction) mu ₂ N and conveyance resistance member 54 (friction force) F Receive ₅ . Even resistive force _{F 5} minute force, _{F 5>} 0, then the sheet _{S 2} is an arrow B a force mu ₂ N and _{F 5} which receives the direction, force mu ₂ for receiving the arrow P direction (conveying direction) Since it exceeds N, it is not conveyed and stopped. In other words, in order to keep the sheet S ₂ is stopped, the relationship of the force is required to be a formula (11).

μ ₂ N + F ₅ > μ ₂ N (11)

After the sheet _{S 3} is conveyed by the predetermined distance _{X 0,} the sheet _{S 1,} the sheet _{S 2,} stopping the driving roller 50 the end of the sheet _{S 3} being in contact with the conveyance resistance member 54, the sheet _{S 1} Sheet S ₂ and Sheet S ₃ are held at the nip portion of the pair of conveying rollers 50 and 51.

  For the fourth and subsequent sheets, the conditions are the same as those for the third sheet conveyance. By repeating this for each sheet, a plurality of sheets can be held by the conveyance roller pairs 50 and 51 and the conveyance resistance member 54. .

As described above, according to this embodiment, the pressing force N of the driven roller 51, the set value Tr of the force of the torque limiter 53, and the resistance force F of the conveyance resistance member 54 to the sheet so as to satisfy the relationship of the above formula. ₅ is set. Further, as described above, the rotation of the driving roller 50 is started at the timing when the downstream end of the sheet conveyance direction reaches the nip portion, the sheet is obliquely fed, and the rotation of the driving roller 50 is brought into contact with the conveyance resistance member. The operation of stopping is repeated for each conveyed sheet. Accordingly, a plurality of sheets can be held with a simple configuration using the pair of conveyance rollers 50 and 51 and the conveyance resistance member 54, and a discharge tray protruding from the image forming apparatus can be eliminated.

[Second Embodiment]
FIG. 6 is an explanatory diagram of a sheet conveying apparatus according to the second embodiment. In addition, description is abbreviate | omitted about the part similar to 1st Embodiment, and the same number is provided to the element which has the same function in a figure.

  The configuration of the sheet conveying apparatus according to this embodiment includes a pair of conveying rollers 50 and 51 and a conveying resistance member 54 as in the first embodiment. However, in this embodiment, the shape of the driving roller is changed to drive the sheet conveying apparatus. The arrangement of the drive transmission means to the roller can be easily performed.

  In general, an image forming apparatus main body is configured such that a driving force is branched from a motor using a gear train or the like and the driving force is transmitted to a plurality of members. For this reason, the gear trains for branching are arranged in parallel in the respective axial directions to increase the drive transmission efficiency of the gears.

  On the other hand, in the first embodiment, a crossing angle θ is provided between the driven roller 51 and the driving roller 50 in order to feed the sheet S obliquely. Therefore, an intersection angle is also generated between the gear 52 of the driving roller 50 and another gear train. Accordingly, in order to ensure the same drive transmission rate as in the past, it is necessary to change the gear shape or increase the positioning accuracy.

  Therefore, in the second embodiment, a tapered roller (drive roller) 60 having a taper shape that becomes narrower toward the conveyance resistance member 54 in the sheet width direction (roller axial direction) is used with respect to the drive roller 50 of the first embodiment. ing. As a result, the crossing angle θ between the driven roller 51 and the driving roller (taper roller) 60 is eliminated, and the conveying roller pairs 60 and 51 are arranged in parallel to the axis. Since the taper roller 60 causes a speed difference in the width direction of the sheet S, the sheet S conveyed by the conveyance roller pair 60 and 51 is conveyed in the arrow C direction while being conveyed in the arrow P direction as in the first embodiment. Send diagonally. Other operations according to the second embodiment are the same as those of the first embodiment, and therefore, a plurality of sheets can be held also by the second embodiment. Furthermore, the second embodiment has the following specific effects.

  The gear 52 mounted on the shaft of the taper roller 60 described above can be disposed in parallel with the shafts of the other gear trains. Compared to the first embodiment, the drive transmission means is disposed on the drive roller (taper roller). Easy to do.

[Third Embodiment]
FIG. 7 is an explanatory diagram of a sheet conveying apparatus according to the third embodiment. In addition, description is abbreviate | omitted about the part similar to 1st, 2nd embodiment, and the same number is provided to the element which has the same function in a figure.

In the present embodiment, the conveyance resistance member 54 is provided so as to be movable in the sheet width direction. Here, the conveyance resistance member 54 is pressed by a coil spring 61, which is a pressure member, in a direction toward the sheet end portion in order to give conveyance resistance to the sheet end portion, and then is stopped by a stopper member (not shown). , Waiting in a predetermined position. Here, the "predetermined position", when the sheet S is stopped after being skew refers to a position abutting the seat width direction end portion, predetermined from the initial position Y ₀ described in the first embodiment distance is a Y ₁ a position spaced. Since the pressure is applied by the coil spring 61, even if the sheets are fed one by one and the end of the sheet is brought into contact with the conveyance resistance member 54, the spring is not pushed back.

  On the other hand, when a plurality of held sheets are extracted or when the conveyance roller pairs 50 and 51 are rotated and discharged, the sheets are overlapped even if the sheet end contacts the conveyance resistance member 54. So do not bend or buckle. By pulling out a plurality of held sheets or rotating and discharging the conveyance roller pairs 50 and 51, the coil spring 61 is contracted and the conveyance resistance member 54 is retracted from the end portion of the sheet. It has the effect of reducing scratches. Note that when the conveyance resistance member 54 is retracted, an actuator for retracting may be provided. By reliably retracting the conveyance resistance member 54 by the actuator, it is possible to prevent the conveyance resistance member 54 from being worn or damaged. Further, a mechanism that performs a retracting operation in conjunction with the rotation of the driven roller 51 may be used. This is because the conveyance resistance member 54 does not need to contact the sheet S while the driven roller 51 is rotating, including when the sheet S enters the conveyance roller pair 50, 51. By making the retracting operation of the conveyance resistance member 54 interlock with the rotation of the driven roller, a reliable retracting operation can be performed.

[Fourth Embodiment]
FIG. 8 is an explanatory diagram of a sheet conveying apparatus according to the fourth embodiment. 8, in a state in which the preceding sheet S ₁ is held stopped after entering the conveying rollers, and shows a state in which succeeding sheet S ₂ comes enters the conveying roller pair. In addition, description is abbreviate | omitted about the part similar to 1st, 2nd, 3rd embodiment, and the same number is provided to the element which has the same function in a figure.

In the present embodiment, reference numeral 62 denotes a sheet width direction edge detection sensor that detects the position of the sheet width direction edge. The sheet width direction edge detection sensor 62 is a sheet width direction position detection unit that is provided upstream of the pair of conveyance rollers 50 and 51 in the sheet conveyance direction and detects the position of the sheet width direction edge. Reference numeral 63 denotes conveyance resistance member moving means for moving the conveyance resistance member 54 in the sheet width direction. Based on the position of the width direction end of the sheet detected by the sheet width direction end detection sensor 62, the position of the conveyance resistance member 54 in the width direction with respect to the sheet is controlled by the conveyance resistance member moving unit 63. Specifically, when the position of the sheet width direction edge detected by the sheet width direction edge detection sensor 62 is shifted to the center side in the sheet width direction compared to the position of the preceding sheet, the detected width direction edge is detected. The conveyance resistance member 54 is moved to the position by the conveyance resistance member moving means 63. That is, the widthwise position of the detected sheet with the initial position Y _0, to its initial position apart from Y ₀ by the predetermined distance Y ₁ position, moves the conveyance resistance member 54.

By using this configuration, even when the position is slightly shifted to the center side in the sheet width direction between the sheet conveyed after the second sheet and the already held sheet, the second and subsequent sheets are used. it is possible to move the conveying resistance member 54 in the mating position in the S _2. In this way, it is possible to give the conveyance resistance by moving the conveyance resistance member 54 to the position corresponding to the sheet conveyed each time. At this time, the movement amount of the conveyance resistance member 54 in the sheet width direction is due to a slight “deviation” when the sheet is set in the sheet cassette and a slight “deviation” generated during conveyance. Therefore, even if the conveyance resistance member 54 is moved in such a manner that the preceding sheet already in contact is pushed in, there is no problem that the end portion of the preceding sheet is broken. On the other hand, if the subsequent sheet is conveyed with a large deviation inward in the width direction due to some factor, it is determined as an error based on detection by the sheet width direction end detection sensor 62, and the job is stopped. . As a result, it is possible to minimize the influence of the conveyance failure.

  Further, when the subsequent sheet end is slightly shifted outward in the width direction from the preceding sheet, the conveyance resistance member 54 is not moved. This is because if the conveyance resistance member 54 is moved outward in the sheet width direction, the preceding sheet cannot be held, and the preceding sheet is pushed out to the succeeding sheet. If the subsequent sheet is conveyed with a large deviation outward in the width direction due to some factor, it is determined as an error by the detection of the sheet width direction end detection sensor 62 and the job is stopped or the conveyance resistance member 54 is stopped. Take measures such as retreating to the outside of the sheet width. As a result, it is possible to minimize the influence of the conveyance failure.

Furthermore, the position to arrange the seat width direction end portion detection sensor 62, as shown in FIG. 8, after entering the preceding sheet S ₁ is the pair of conveying rollers 50 and 51, from the trailing edge of the sheet when stopped Also, the upstream side in the sheet conveying direction (L1 <L2). By disposing such a position, the widthwise position of the subsequent sheet S ₂ also becomes possible to detect, in the mating position to come then enters the sheet, moves the conveyance resistance member 54 be able to.

[Fifth Embodiment]
9 and 10 are explanatory views of a sheet conveying apparatus according to the fifth embodiment. In addition, description is abbreviate | omitted about the part similar to 1st, 2nd, 3rd, 4th embodiment, and the same number is provided to the element which has the same function in a figure.

  In the present embodiment, the cross-sectional shape of the contact surface (contact surface) with which the sheet end portion of the conveyance resistance member 64 contacts is a round shape (arc shape) as shown in FIGS. Therefore, even if the posture (angle) of the sheet S that has been conveyed as shown in FIG. 9 is in contact with the conveyance resistance member 64 for some reason is different from that of the preceding sheet, the conveyance resistance member 64 and the sheet S A sufficient contact state can be ensured. In this way, it is possible to give a sufficient conveyance resistance to the sheet S. The cross-sectional shape of the sheet contact surface of the conveyance resistance member 64 is not limited to the round shape (arc shape). For example, a similar shape (polygonal shape) in which a short straight line forms an angle and continues in a substantially arc shape. An effect can be obtained.

  Furthermore, it is also preferable that the conveyance resistance member 64 can rotate in the sheet conveyance direction in the arrow direction shown in FIG. FIG. 10 shows a state in which a plurality of sheets S are held in an overlapping state and the operation moves to an operation of pulling out or discharging the sheets. The friction between the sheet end portion and the conveyance resistance member can be reduced by rotating the conveyance resistance member 64 in the direction of the arrow in the drawing when a plurality of stacked sheets are pulled out or discharged. Thereby, wear and scratches on the conveyance resistance member 64 can be reduced.

  Note that after the sheet is pulled out or discharged, the conveyance resistance member 64 returns to the initial position.

[Other Embodiments]
In the above-described embodiment, the configuration in which the conveyance resistance member is movably provided is illustrated, but the configuration is not limited to the above-described configuration. For example, the conveyance resistance member may be moved in the direction of retreating from the end portion of the sheet in conjunction with the start and stop of rotation of the driven roller. In this case, the conveyance resistance member moves in conjunction with the rotation start and rotation stop of the driven roller when the sheet held by the conveyance resistance member and the conveyance roller pair is pulled out or driven by driving the driving roller. Configure. Even if comprised in this way, the friction of a sheet | seat edge part and a conveyance resistance member can be reduced similarly to embodiment mentioned above, and the abrasion and damage | wound of a conveyance resistance member can be reduced.

  In the above-described embodiment, the torque limiter is exemplified as the brake means. However, the present invention is not limited to this. For example, an electromagnetic brake or the like that applies a force in the direction opposite to the sheet conveying direction to the driven roller. If so, other brake means may be used. This brake means is effective to hold the first sheet guided to contact with the driving roller well in a state where it is nipped by the pair of conveying rollers without damaging the second sheet. Similarly to the above, the first sheet may be brought into contact with the conveyance resistance member.

  In the above-described embodiment, the driving roller forming the pair of conveying rollers is exemplified by the configuration in which the roller portion (circumferential surface) that contacts the sheet is continuously provided in the axial direction. However, the configuration is not limited thereto. . For example, the roller part (circumferential surface) which contacts a sheet | seat may be the structure divided | segmented and arrange | positioned in the axial direction. Further, the drive roller may not be provided integrally in the axial direction. Specifically, drive rollers provided on both sides in the axial direction may be used. The driving roller may have another configuration as long as the driven roller and the sheet are nipped and conveyed, and the sheet is obliquely fed toward the conveyance resistance member.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. Further, an image forming apparatus that uses a sheet carrier and sequentially superimposes and transfers the toner images of the respective colors on the sheet carried on the sheet carrier. Further, an image forming apparatus that uses an intermediate transfer member, sequentially transfers toner images of respective colors on the intermediate transfer member, and collectively transfers the toner images carried on the intermediate transfer member onto a sheet. good. Similar effects can be obtained by applying the present invention to a sheet conveying apparatus used in these image forming apparatuses.

  Further, in the above-described embodiment, the sheet conveying apparatus integrally included in the image forming apparatus is exemplified, but the present invention is not limited to this. For example, the image forming apparatus may be a detachable sheet conveying apparatus, and the same effect can be obtained by applying the present invention to the sheet conveying apparatus.

  Further, in the above-described embodiment, the sheet conveying apparatus that conveys a sheet such as recording paper as a recording target is exemplified, but the present invention is not limited to this. For example, the same effect can be obtained even if the present invention is applied to a sheet conveying apparatus that conveys a sheet such as a document to be read.

S ... sheet 50 ... driving rollers 50, 51 ... conveying roller pair 51 ... driven roller 53 ... torque limiter 54 ... conveying resistance member 55 ... sheet conveying direction end detection sensor 56 ... guide 57 ... discharge port 62 ... sheet width direction end Detection sensor 90 ... image forming apparatus

Claims (12)

A nip portion is formed between the driving roller that conveys the sheet in the conveying direction and conveys the sheet to one side in the width direction orthogonal to the conveying direction, and the driven roller that is driven to rotate while being pressed against the driving roller, and sandwiches the sheet. A pair of transport rollers that transport
A conveyance resistance means that abuts on one end in the width direction of the sheet nipped and conveyed by the conveyance roller pair, and applies conveyance resistance to the sheet;
Have
The rotation of the driving roller is started in order to cause the guided sheet to enter the nip portion, the sheet is sandwiched by the pair of transport rollers and transported in the transport direction toward the transport resistance unit, and the transport roller The operation of stopping the driving roller in a state where the one end portion of the sheet sandwiched between the pair is in contact with the conveyance resistance means is repeated for each guided sheet, and the conveyance roller pair and the A sheet conveying apparatus characterized in that a sheet is held by a conveying resistance means.   The conveyance resistance means is separated from the one end in the width direction of the sheet by a predetermined distance so that one end in the width direction of the sheet abuts when the sheet is conveyed by a predetermined distance by the pair of conveyance rollers. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is disposed at a predetermined position.   The sheet conveying apparatus according to claim 1, wherein the driving roller intersects the driven roller at a predetermined angle θ and is inclined to one side in a sheet width direction.   2. The sheet conveying apparatus according to claim 1, wherein the driving roller is a tapered roller that becomes narrower toward the conveying resistance means in the width direction of the sheet.   In order to control the timing of the rotation start and rotation stop of the drive roller, a sheet conveyance direction position detection unit that detects a position in the sheet conveyance direction upstream of the pair of conveyance rollers is provided. The sheet conveying apparatus according to any one of claims 1 to 4.   The sheet conveying apparatus according to any one of claims 1 to 5, wherein the conveyance resistance means is provided so that a contact surface with which a sheet end abuts is movable.   The conveyance resistance means is provided so as to be movable in a direction in which the sheet held by the conveyance resistance means and the conveyance roller pair is retracted from the end of the sheet by the sheet when the sheet is pulled out or conveyed by driving a driving roller. The sheet conveying apparatus according to claim 6, wherein the sheet conveying apparatus is a sheet conveying apparatus.   The conveyance resistance means is configured to pull out the sheet held by the conveyance resistance means and the conveyance roller pair or drive the driving roller to convey the sheet in conjunction with the rotation start and rotation stop of the driven roller. The sheet conveying apparatus according to claim 6, wherein the sheet conveying apparatus moves in a direction of retreating from the end portion.   A sheet width direction position detecting unit for detecting a position in the width direction end of the sheet, and a moving unit for moving the conveyance resistance unit in the sheet width direction upstream of the pair of conveying rollers in the sheet conveying direction; If the position of the width direction end of the sheet detected by the width direction position detecting means is shifted to the center side in the sheet width direction compared to the position of the preceding sheet, the detected position of the width direction end of the sheet 9. The sheet conveying apparatus according to claim 1, wherein the conveying resistance unit is moved by the moving unit to a position separated from the initial position by a predetermined distance. .   10. The sheet conveying apparatus according to claim 1, wherein a cross-sectional shape of a sheet contact surface of the conveying resistance unit is an arc shape or a polygonal shape. The driven roller has brake means for applying a force in a direction opposite to the sheet conveying direction;
When the friction coefficient of the driving roller with respect to the sheet is μ ₁ , the friction coefficient between the sheets is μ ₂ , and the radius of the driven roller is R, F ₅ <μ ₁ N and μ ₁ N> Tr / R ≧ μ ₂ The pressing force N of the driven roller, the set value Tr of the force of the brake means, and the resistance force F _{5 of} the conveyance resistance means to the sheet are set so as to satisfy the relationship of N. The sheet conveying apparatus according to any one of 10.   An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and the sheet conveying device according to any one of claims 1 to 11.

Images