JP2007145476A - Sheet material reversing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size and cost of a device by providing a sheet material reversing device of a non-actuator. <P>SOLUTION: This sheet material reversing device is provided with a simple mechanical timer constituted only of parallel pins and gears on a carrier roller shaft, and performs carrier flapper switching operation by a friction clutch in a state of stopping carrying of a sheet material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet material reversing device provided in a conveyance path of a sheet material conveyance device used in an image forming apparatus such as a copying machine, a facsimile machine, or a printer.

  2. Description of the Related Art Image forming apparatuses having a double-sided printing function such as a copying machine, a facsimile machine, and a printer are provided with a sheet material reversing device for reversing the front and back of a sheet material in the conveyance section. A general configuration includes a flapper for switching the conveyance paths at a plurality of sheet material conveyance path joining portions. The sheet material to be conveyed is once buffered in a predetermined sheet material conveyance path, and after the switching operation of the flapper means is performed, the roller pair holding the sheet material is reversed to perform the reverse operation on the conveyance path. The front and back sides of the sheet material are reversed by exchanging the front and rear ends of the sheet material. The sheet material is re-fed to the image forming unit to achieve double-sided printing.

The image forming apparatus main body for double-sided printing described in Patent Document 1 includes the sheet material reversing device having the above-described configuration having a flapper, and achieves sheet material leading edge registration in the conveyance path of the image forming apparatus. Examples of invention are specified.
Japanese Patent Laid-Open No. 4-327447 (Page 5, Figure 1)

  The flapper “second switching guide” described in Reference 1 is not configured to be switched by the driving force of the sheet material conveyance roller, but is explicitly described as being configured to be switched by a solenoid (not shown).

  According to Reference 1, the sheet material conveyance must be temporarily stopped while the flapper “second switching guide” is switched to a predetermined position. To realize the operation, the flapper is operated by a solenoid and the roller pair is operated by a plurality of clutches. Each is driven independently.

  However, the sheet material reversing device having a solenoid only for the switching operation of the flapper is not suitable for downsizing of the device but also increases the cost.

  Accordingly, an object of the present invention is to switch the flapper without requiring an actuator and stopping the driving source, while the configuration is such that the switching driving of the flapper and the rotational driving of the associated roller pair are operated by a common driving source. By providing a sheet material reversing device capable of stopping sheet material conveyance for a time required for operation, it is possible to reduce the size and cost of the apparatus.

The sheet material reversing device according to claim 1 of the present invention,
In the transport path having the transport path switching means located in the first posture in the transport section between the first transport section and the second transport section, on the driving roller shaft of the roller pair disposed in the second transport section An engagement portion is formed, and the drive roller and the drive transmission means rotate together as a result of the engagement portion abutting on the drive transmission means that is rotationally fitted around the drive roller shaft. In a friction transmission means that is formed with an engaged portion and presses the friction member and the friction member against each other to transmit a driving force, the friction member is connected to a driving means for rotating the driving transmission means The friction member is connected to the conveying path switching means with respect to the apparatus configuration.
The drive means continues to rotate forward in the direction in which the sheet material is conveyed from the first conveyance section to the second conveyance section, and after the trailing edge of the sheet material passes the conveyance path switching means, to the third conveyance section By reversing the driving means for carrying the sheet material, a reduction ratio sufficient to stop the rotation of the driving roller pair while the conveying path switching means is moving from the first position to the second position is obtained. The driving force is transmitted from the driving means to the drive transmitting means by the driving system, and the sheet material is reversely conveyed from the first conveying unit to the third conveying unit.

  Although it is a configuration in which the switching drive of the flapper and the rotational drive of the associated roller pair are operated by a common drive source, the actuator is not required and only the time required for the switching operation of the flapper without stopping the drive source, By providing a sheet material reversing apparatus capable of stopping the sheet material conveyance, it is possible to realize apparatus downsizing and cost reduction.

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

  FIG. 1 is a view of the main body of an inkjet image forming apparatus with central reference transport having a double-sided printing function according to the present invention. The flow of the sheet material conveyance and the description of the sheet material reversing device which is a feature of the present invention are as follows.

  The sheet material 5 loaded and accommodated in the cassette 2 is separated by a sheet feeding roller 6 and is fed into a sheet material conveyance path indicated by a one-dot chain line in the image forming apparatus main body 1. The configurations of the conveying roller pair 10, 12, 13, 21 and the spur obliquely feeding roller pair 15, 16, 17 arranged in the image forming apparatus main body 1 are all driven by the side located on the image forming surface side of the sheet material. It becomes a spur roller, and the opposite side is a drive roller. For this reason, the image forming surface in the course of drying is likely to occur when it passes through the roller, i.e., the ink is transferred to the roller surface and contaminated, and the stain is transferred one after another to the surface of the sheet material. It has a structure to prevent.

  After the separated sheet material passes through the conveying roller pair 7, if the leading end is sandwiched by the LF roller pair 9, printing is possible. Inkjet head provided while the carriage 3 reciprocates while the carriage 3 reciprocating in the vertical direction of the paper and the LF roller pair 9 conveying the separated sheet material move intermittently. 4 achieves predetermined image formation on the surface of the sheet material by ejecting ink droplets toward the surface of the sheet material. The leading edge of the sheet material is conveyed in the direction toward the outside of the image forming apparatus main body 1 after passing through the flapper 11 and the conveying roller pairs 12 and 13 according to the progress of image formation. In the case of single-sided printing, the sheet material is discharged out of the machine while remaining in that direction. On the other hand, in the case of duplex printing, when the rear end of the sheet material on which image formation has been completed is positioned in the conveyance section of the conveyance roller pair 12 and 13, a motor (not shown) that rotates the conveyance rollers 12 and 13 is reversed.

  By the reverse rotation of the motor (not shown), the flapper 11 connected to the motor via the friction clutch is rotated upward (in the direction of the arrow in the figure) so as to switch the conveyance path. Since the driving force from the motor is not transmitted for a predetermined time, the conveying roller pairs 12 and 13 stop conveying the sheet material for a time sufficient for the rotation of the flapper 11 while holding the sheet material.

  When the motor is continuously driven in the reverse direction, the driving force of the motor (not shown) is transmitted to the pair of conveying rollers 12 and 13, and this time, toward the conveying guide 14 constituting the double-sided conveying path with the trailing edge of the sheet material as the leading edge. Carries sheet material.

  When the sheet material passes through the conveyance guide 14, the sheet material is alternatively conveyed along a conveyance path corresponding to the sheet width, and a spur skew feeding roller pair 15 serving as one of the sheet material skew feeding means. , 16,17. As a result, the registration operation is performed so that the sheet material is properly positioned at the design reference position corresponding to each sheet width.

  By this series of conveyance operations, the front and back sides of the sheet material printed on one side are reversed, and after passing through the conveyance roller pairs 21 and 8, the sheet material is fed again toward the LF roller pair 9 which is an image forming unit, This time, an image forming operation is performed on the back surface of the sheet material, and the sheet is discharged by the conveying roller pairs 12 and 13 to achieve double-sided printing.

  FIG. 2 is a cross-sectional view of the sheet material reversing device.

  The first to third conveyance sections according to claim 1 are as described in the sheet material conveyance section, and the conveyance switching means is the flapper 11, and the spring 111 is pulled in one direction so as to be in the direction 11b. Is working. The first posture described in claim 1 of the flapper 11 as the transport switching means is the state 11a, and the second posture is the state 11b. The roller pair described in claim 1 is the conveying roller pair 12, and the driving roller is 12a.

  FIG. 3 is an overall view of the sheet material reversing device of the double-sided conveyance path, and the drive system diagram between corresponding components is FIG. Here, the engaging portion on the drive roller shaft according to claim 1 is the parallel pin 108, the drive transmission means is the gear 106, the friction transmission means is the friction clutch 104, and the drive means is the motor 101.

(Configuration of friction clutch 104)
FIG. 5 shows the configuration of the friction clutch 104.

  The friction member according to claim 1 is the gear 104b, and the non-friction member is the arm member 104a. It is a member for positioning.

  The friction clutch is composed of four parts: an arm member 104a, a gear 104b, a retaining ring 104c, and a compression spring 104d. A gear 104b including a compression spring 104d is fastened by a retaining ring 104c so as to engage with a shaft portion of the arm member 104a. Since the pressing force of the compression spring 104d is received by the opposing surfaces of both the arm member 104a and the gear 104b (arrow part), when the gear 104b is driven, it is integrated with the arm member 104a by the frictional force. Rotate. However, if a load greater than the above friction torque is applied to the arm member 104a, the arm member 104a slips on the friction surface, and the gear 104b and the arm member 104a have a rotational difference and are mechanical elements that are different from each other. Function.

(Configuration of drive roller 12a)
FIG. 4 shows the configuration of the drive roller 12a.

  The engaging portion of claim 1 is a //// portion formed on the gear 106 as drive transmission means, and the engaged member is a parallel pin 108.

  The driving roller 12a constituting the conveying roller pair 12 is shaft-fitted with the gear 16 of the driving train shown in the drawing through the parallel pin 108 through its shaft. Similarly, the driving roller 13a that constitutes the conveying roller pair 13 passes through the parallel pin 108 on its shaft and is shaft-fitted with the pulley 107 shown in the figure.

  The driving roller 12a is supported by a bearing (not shown), and the driving force is not transmitted when the engagement portion of the gear 106 and the parallel pin 108 on the driving roller 12a are not in contact with each other.

  This configuration is a mechanical element that functions as a mechanical timer in the drive system.

  FIG. 3 is an overall view of the sheet material reversing device in the double-sided conveyance path.

  Here, when the motor 101 is driven to rotate in a predetermined direction, the entire drive system composed of the gears and pulleys is driven to rotate. When the friction clutch 104 rotates in the direction indicated by the arrow CCW, the hatched portion ///// Can be brought into contact with the flapper, and the flapper 11 can be pushed down in the arrow DOWN direction to the first posture shown in FIG. 2 so that the first conveying unit can be conveyed.

  As described in FIG. 1 above, if the rear end of the sheet material imaged on the surface passes through the roller pair 12 and then the motor 101 is operated in reverse, the parallel pin 108 is connected to the gear 106 as in the configuration of the drive roller 12a. And the driving force of the gear 106 is not transmitted to the driving roller 12a, and as a result, the conveyance of the sheet material by the conveying rollers 12 and 13 is stopped.

  On the other hand, since the friction clutch 104 is rotating in the reverse direction, the arm member 104 that has continued to urge the flapper 11 in the first posture rotates in the release direction from the flapper 11, and the flapper 11 is driven by the acting force of the spring 111. After being positioned in the position 2, the driving force is transmitted to the conveying rollers 12 and 13, and the sheet material can be guided to the duplex conveying path.

  As described above, the switching drive of the flapper and the rotational driving of the associated roller pair are operated by a common driving source, but the actuator is not required and the switching operation of the flapper is not required without stopping the driving source. By providing a sheet material reversing apparatus capable of stopping sheet material conveyance for a short time, it is possible to reduce the size and cost of the apparatus.

Image forming apparatus main body. The sheet material inversion apparatus cross-section enlarged view of a double-sided conveyance path. The sheet material inversion apparatus whole view of a double-sided conveyance path | route. Explanatory drawing of conveyance roller pair 12. FIG. Explanatory drawing of the friction clutch 104. FIG. Drive system diagram.

Explanation of symbols

1 Image forming device
2 cassette
3 Carriage
4 Inkjet head
5 Sheet material
6 Feed roller
7 Conveyor roller pair
7a Drive roller
7b Followed roller
8 Transport roller pair
8a Drive roller
8b driven roller
9 LF (line feed) roller pair
9a Drive roller
9b Followed roller
10 Transport roller pair
10a Drive roller
10b driven spur roller
11a Flapper in first position
11b Flapper in second position
12 Transport roller pair
12a Drive roller
12b driven spur roller
13 Transport roller pair
13a Drive roller
13b driven spur roller
14 Transport guide
15 spur skew feeding roller pair
15a Drive roller
15b driven spur roller
16-spur inclined roller pair
16a Drive roller
16b driven spur roller
17 Spur-feed roller pair
17a Drive roller
17b driven spur roller
21 Conveyor roller pair
21a Drive roller
21b driven spur roller
22 Transport guide
101 motor
102a pulley
102b gear
103 Gear
104 Friction clutch
104a Arm member
104b gear
104c retaining ring
104d compression spring
105 gear
106 gear
107 pulley
108 parallel pins
109 Belt 1
110 Belt 2
111 Spring
112 engaged part
P, Pn (n = 1,2,…) Sheet material

Claims (1)

In the transport path having the transport path switching means located in the first posture in the transport section between the first transport section and the second transport section, on the driving roller shaft of the roller pair disposed in the second transport section An engagement portion is formed, and the drive roller and the drive transmission means rotate together as a result of the engagement portion abutting on the drive transmission means that is rotationally fitted around the drive roller shaft. In a friction transmission means that is formed with an engaged portion and presses the friction member and the friction member against each other to transmit a driving force, the friction member is connected to a driving means for rotating the driving transmission means The friction member is connected to the conveying path switching means with respect to the apparatus configuration.
The drive means continues to rotate forward in the direction in which the sheet material is conveyed from the first conveyance section to the second conveyance section, and after the trailing edge of the sheet material passes the conveyance path switching means, to the third conveyance section By reversing the driving means for carrying the sheet material, a reduction ratio sufficient to stop the rotation of the driving roller pair while the conveying path switching means is moving from the first position to the second position is obtained. A sheet material reversing apparatus characterized in that a driving force is transmitted from the driving means to the drive transmitting means by a driving system, and the sheet material is reversed and conveyed from the first conveying unit to the third conveying unit.

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