JP3198124B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passage changing claw provided at an entrance of a reversing path and capable of switching between a receiving position for receiving a sheet in the reversing path and a feeding position for sending out the paper from the reversing path. A pair of reversing and conveying rollers, one of which is provided to be able to contact and separate from the other roller, and when the sheet fed into the reversing path is reversibly conveyed by the pair of reversing rollers, the path changing claw is provided. The present invention relates to an image forming apparatus provided with a sheet reversing mechanism that conveys a sheet toward a duplex unit by switching the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer having a double-sided function is provided with a reversing mechanism for reversing a sheet fed by a double-sided unit. FIG. 4 is an explanatory view showing an example of the reversing mechanism. This type of reversing mechanism is shown in FIG.
As shown in FIG. 7, a lever branch claw 35 for rotating the passage changing claw 33 and an inversion passive roller 34 which is one of the inversion rollers are provided.
And a reversing lever 36 that rotates the roller to contact a reversing drive roller (not shown) is directly connected to the same link lever 32 connected to the solenoid 31. Such a reversing mechanism can be provided at low cost because the path changing claw 33 and the reversing passive roller 34 are operated by the sole drive source of the solenoid 31.

[0003]

However, when the solenoid 31 is driven by the same link lever 32 to actuate the path changing claw 33 and the reversing passive roller 34 via the lever branching claw 35 and the reversing lever 36, respectively, the lever is branched. The reversing passive roller 34 presses against the reversing drive roller to reversibly convey the sheet before the path changing claw 33 comes to the feeding position due to the position tolerance between the claw 35 and the reversing lever 36, the assembly tolerance, and the like. (Not shown), there is a problem that a paper jam occurs.

[0004] The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide an image forming apparatus provided with a reversing mechanism capable of reliably preventing paper jam when the paper is reversed.

[0005]

In order to achieve the above object, the present invention is provided at an entrance of a reversing path, and is switchable between a receiving position for receiving a sheet in the reversing path and a feeding position for sending out the sheet from the reversing path. A path changing claw, and a pair of reversing transport rollers provided in the reversing path, one roller being capable of coming in contact with and separating from the other roller, and the sheet fed into the reversing path is reversed by the reversing roller pair. When transported,
In an image forming apparatus provided with a sheet reversing mechanism that is conveyed toward a duplex unit by switching the path changing claw, a single drive source that performs an operation of switching the path changing claw is provided, and the path changing claw is operated by the driving source. Is activated,
The operation of the passage changing claw is transmitted to one of the reversing rollers via a spring, and the operation of bringing one of the reversing rollers into contact with or separating from the other roller is performed.

[0006]

[0007]

According to the above construction, the operation in which one of the reversing rollers comes into contact with the other roller and reversely conveys the operation of the path changing claw to the reversing roller via the spring, so that the operation of the path changing claw is reduced. The operation timing of the reversing roller can be reliably delayed, and it is possible to prevent one roller of the reversing roller from contacting the other roller prior to the operation of the passage changing claw.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory view showing one embodiment of the reversing mechanism according to the present invention.

In FIG. 1, reference numeral 1 denotes a reversing mechanism,
The reversing mechanism 1 is disposed between a fixing device (not shown) and a duplex unit. The reversing mechanism 1 is provided with a reversing path 4 formed by the passage changing claw 2 and the guide plate 3.
A transport drive roller 5 and a first roller 6 for transporting a sheet (not shown) sent from the direction into the reversing path 4 are provided. In the lower part of the reversing path 4, reversing rollers 7, 8 for reversing the sheet (not shown) fed into the reversing path in the reverse direction, that is, the direction of arrow B, are provided. The sheet is conveyed in the direction of arrow C via the lower flow path 10B by the conveyance drive roller 5 and the second roller 9 provided at the upper portion, and is sent to the duplex unit.

The passage changing claw 2 is fixed to a lever branch claw 14 mounted rotatably about a shaft 13, and the lever branch claw 14 is connected to a link lever 12 connected to a solenoid 11 as a driving source. Have been. in this case,
The lever branch claw 14 has an elongated hole 15A formed therein.
5A, the pin 15B fixed to the link lever 12 is fitted, so that the lever branch claw 14 and the link lever 1 are connected.
2 are connected. The passage changing claw 2 is swung between the receiving position shown in FIGS. 1 and 2 and the sending position shown in FIG. 3 by the solenoid 11.

The reversing rollers 7 and 8 comprise a reversing driving roller 7 fixed at a position provided on the right side and a reversing passive roller 8 on the left side. The reversing passive roller 8 is rotatable about a shaft 16. It is supported by the mounted reversing lever 17. The reversing lever 17 is connected to the lever branch claw 14 by a reversing spring 18.
Reference numeral 19 denotes the reversing passive roller 8 and the reversing driving roller 7.
It is a spring for holding at a separated position away from the main body.

The operation mode of the reversing mechanism 1 thus configured is as follows.
It is as follows. When the double-sided command is issued, the sheet is conveyed from the direction of arrow A through the upper flow path 10A, and this sheet is sandwiched between the conveyance driving roller 5 and the first roller 6 and enters the reversing path 4. At this time, the passage changing claw 2 is held at the receiving position shown in FIGS. 1 and 2 because the solenoid 11 is turned off, and the reversing passive roller 8 is also held at the separated position. When the trailing edge of the sheet comes off the transport driving roller 5 and the first roller 6, the solenoid 11 is turned on, and the lever branch claw 14 connected to the link lever 12 is rotated about the shaft 13 as shown in FIG. It turns clockwise and moves to the delivery position. By this movement, the reversing lever 17 connected to the lever branch claw 14 via the reversing spring 18 rotates clockwise about the shaft 16, and the paper is held between the reversing driving roller 7 and the reversing passive roller 8.

The sheet sandwiched between the reversing drive roller 7 and the reversing passive roller 8 is reversed and the rear end becomes the leading end, and is guided by the path changing claw 2 toward the nip between the transport driving roller 5 and the second roller 9. It is transported in the direction of arrow B. When the sheet is nipped between the transport driving roller 5 and the second roller 9, the lower flow path 10
It is sent in the direction of arrow C through B.

Thus, the sheet is reversed by the reversing mechanism 1 and conveyed to the duplex unit. In this embodiment, the passage changing claw 2 is directly switched from the receiving position to the delivery position by the solenoid 11, whereas the sheet is reversed. The passive roller 8 is indirectly switched from the separated position to the sheet holding position via the reversing spring 18. Therefore, a shift occurs in the timing of switching between the path changing claw 2 and the inversion passive roller 8, and the drive is transmitted to the inversion passive roller 8 after the path changing claw 2 is switched. It is possible to reliably prevent paper jam caused by switching before the second sheet.

[0015]

According to the first aspect of the present invention, the operation in which one of the reversing rollers is in reverse contact with the other roller is transmitted to the reversing roller via the spring, and the operation of the path changing claw is transmitted to the reversing roller. The operation timing of the reversing roller with respect to the operation of the changing claw can be reliably delayed, and it is possible to prevent one roller of the reversing roller from contacting the other roller prior to the operation of the passage changing claw.

[0016]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an aspect at the time of receiving a sheet.

FIG. 3 is an explanatory view showing an aspect at the time of sheet feeding.

FIG. 4 is an explanatory view showing a part of a conventional reversing mechanism.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 reversing mechanism 2 passage changing claw 4 reversing path 7, 8 reversing roller 11 solenoid 18 reversing spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-172154 (JP, A) JP-A-2-108966 (JP, U) JP-A-1-137952 (JP, U) JP-A-56 123338 (JP, U) Fully open 63-58,858 (JP, U) Fully open, 62-113155 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) G03G 15/00 B65H 15 / 02-15/02 B65H 29/58-29/64

Claims (1)

(57) [Claims] A path changing claw provided at an entrance of the reversing path and capable of switching between a receiving position for receiving a sheet in the reversing path and a sending position for sending out the paper from the reversing path; and one roller provided in the reversing path. Has a reverse transport roller pair that can be brought into contact with and separated from the other roller, and when the sheet fed into the reverse path is reversely transported by the reverse roller pair,
An image forming apparatus including a sheet reversing mechanism that is conveyed toward a duplex unit by switching the path changing claw, wherein a single drive source for performing an operation of switching the path changing claw is provided, and the path changing claw is operated by the driving source. Is operated, the operation of the passage changing claw is transmitted to one of the reversing rollers via a spring, and an operation is performed in which one of the reversing rollers contacts and separates from the other roller. Image forming apparatus.