JPH0721659B2 - Paper alignment device - Google Patents

Description

The present invention relates to a sheet aligning device for an image forming apparatus, and more specifically, for example, in automatic double-sided printing, when printing the front surface and then the back surface, the lateral resist is determined. The present invention relates to a sheet aligning device for performing.

[Conventional technology]

As shown in FIG. 6, the conventional sheet aligning apparatus is composed of a switch back mechanism 6, a preliminary shift mechanism 23, a skew feed roller mechanism 9 and a lateral registration plate 14. In this type of apparatus, since the preliminary shift mechanism 23 is independently provided between the switch back mechanism 6 and the oblique feeding mechanism 9, the number of parts tends to increase. Further, the entire apparatus becomes complicated, and moreover, the switchback mechanism and the preliminary shift mechanism, and the preliminary shift mechanism and the skew feed roller mechanism must be provided with sufficient intervals to allow the print paper to be skewed sufficiently, which necessitates the enlargement of the apparatus. It was As described above, in the conventional device, the major drawbacks are the increase in complexity, the increase in size, and the inevitable increase in cost.

[Object of the Invention]

As described above, in the conventional example, there have been problems in that the device is large, complicated, and high in cost. Therefore, the present invention eliminates the preliminary shift mechanism by adding the function of the preliminary shift mechanism to the switchback mechanism, and improves the above-mentioned problem.

〔Example〕

FIG. 1 shows an embodiment of the present invention, 3 is a fixing device composed of a heat roller 1 and a press roller 2, 6 is a switch back mechanism composed of a reversing roller 24 and a reversing roller 25, 9 is a skew feeding roller 7 and a skew feeding roller 8 An oblique feeding roller mechanism consisting of 14 in the plan view (FIG. 1 (a)) is a lateral resist plate which is a lateral resist reference surface, 12 is a re-feed roller 10 and a re-feed roller.
It is a re-feeding mechanism consisting of 11.

The print paper transferred from the photoconductor 28 (FIG. 5) to the first surface is sent in the direction of arrow 15 and fixed by the fixing device 3. The reversing roller 25 feeds the print paper in the direction of the arrow 16 until the trailing edge of the print paper is switched over and reaches the point 13, and when the trailing edge of the print paper is switched over and reaches the point (switch SW
Detects the trailing edge) and reverses (at the same time the flap F switches), and the print paper is conveyed in the directions of arrows 17 and 18.

However, in the plan view, when the print paper is advancing in the direction of arrow 18, the left end of the print paper and the lateral registration reference plane are on the same straight line, so there is no problem if it shifts to the right in the traveling direction, but only slightly to the left. However, if they are misaligned, they may hit the front surface 14a of the lateral resist plate, causing problems such as tip breakage or jamming. It is theoretically possible to convey the print paper so as not to shift it at all, but it is very difficult to actually carry it because extremely high-precision parts are required. Therefore, in the past, as shown in the previous section, a preliminary shift mechanism that skews the print paper in the direction opposite to the lateral resist plate was provided, but this method increases the size, complexity, and cost of the entire device as described above. Was a problem.

In order to solve the above-mentioned problems, the present invention provides a switchback mechanism with a preliminary shift function.
Shown in the figure.

As shown in the figure, the reversing roller 24 as a roller body is provided with a backlash 20a as a roller axis crossing means on one side of the bearing portion. Travel at right angles to their axes. However, when the reverse roller 25 reverses, the reverse roller 24
Due to friction with the print paper, it is inclined by the amount of the backlash 20a provided on the bearing portion on one side, and is inclined as shown in FIGS. 3 (a) and 3 (b). By providing this play 20a in the reversing roller bearing portion on the side of the horizontal resist plate, the print paper is skewed in the direction opposite to that of the horizontal resist plate, and the function of the preliminary shift mechanism is provided.

A guide plate 14 is provided for shifting from the central reference conveyance to the one-side reference conveyance. This is because the configuration of the lateral registration roller and the like becomes complicated if the lateral registration is performed while the center reference is maintained. (It is necessary to change the resist amount depending on the paper size, etc.) FIG. 4 shows another embodiment, in which the bracket 37 having the bearing portion of the reversing roller 38 is used as the solenoid 36 around the fulcrum 34.
The mechanism of roller axis crossing means for skewing the print paper by moving the roller 38 to tilt the roller 38 is shown. 35 is a link.

〔The invention's effect〕

As described above, by combining the switchback mechanism with the preliminary shift function by the roller axis crossing means,
Since the separately-arranged preliminary shift mechanism is omitted, the path length of the device is significantly shortened, and there is an effect that the device can be easily downsized, simplified, and reduced in cost.

[Brief description of drawings]

1 (a) is a plan view showing the outline of the present invention, FIG. 1 (b) is a front view thereof, and FIGS. 2 (a) and 2 (b) are views of a switchback mechanism applied to the present invention. A plan view, a front view, and FIGS. 3A and 3B showing details of the example are shown in FIG.
FIG. 6B is a plan view showing the operation of FIG. 6B, a front view, FIG. 4 is a plan view showing another embodiment, FIG. 5 is a front view of a copying machine to which the present invention is applied, and FIG. b) is a plan view and a front view showing a conventional example. 20a …… Backlash (roller axis crossing means) 24 …… Reversing roller (roller body) 25 …… Reversing roller (roller body) 26 …… Switchback mechanism 34 …… Support point (roller axis crossing means) (second embodiment) 36 ... Solenoid (roller axis crossing means) (second embodiment) 37 ... Bracket (roller axis crossing means) (second embodiment)

Front Page Continuation (72) Inventor Takahiro Kuroda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Instructor Haruka Sekiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshifumi Moriya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji Baba 340, Kurosawa-machi, Minamikoma-gun, Yamanashi Nihon Seimitsu Kogyo Co., Ltd. (56) References JP-A-60-114876 (JP, A) JP-A-61-101339 (JP, A) JP-A-62-73285 (JP, A)

Claims (1)

[Claims] 1. A sheet aligning device for an image forming apparatus such as a copying machine or a laser printer having a sheet path for receiving a sheet on which an image is formed from an image forming section and guiding the sheet to the image forming section again by a switchback mechanism. In the switchback mechanism, the switchback mechanism is composed of a pair of forward and backward rotatable roller bodies that sandwich a sheet and roll contact with each other, and at the time of the switchback operation, the rotation shaft of one roller body of the roller body is rotated by the other roller body. Intersect the rotation axis of
A sheet aligning device comprising roller axis crossing means for switching back the sheet while shifting the sheet in the sheet width direction.