JPH079548B2 - Double-sided image forming device - Google Patents

Description

The present invention relates to a double-sided image forming apparatus such as a double-sided electrophotographic copying machine or a double-sided laser beam printer for forming images on both front and back sides of a sheet.

[Problems to be Solved by Prior Art and Invention]

Since the conventional double-sided image forming apparatus has an intermediate tray for temporarily storing the image-formed sheet on the first side, when a large size sheet is used, the intermediate tray becomes large,
There is a problem that the entire device becomes large. Also, because of that, it is necessary to release more parts at the time of jam processing, so that there is a problem that the jam processing property is poor and that it is easy to forget to remove the jammed paper and the residual paper in the machine at the time of jamming. It was

[Object of the Invention]

It is an object of the present invention to solve the above problems of the conventional device and to downsize the device. Another object of the present invention is to provide a double-sided image forming apparatus capable of performing double-sided image formation on a large size sheet in spite of downsizing the apparatus.

Still another object of the present invention is to provide a double-sided image forming apparatus with improved operability in jam processing.

〔Example〕

FIG. 1 shows a double-sided image forming apparatus which is an embodiment of the present invention. A sheet 1 is stored in the cassette 1a. Reference numeral 2 is a paper feed roller, 3 is a registration roller, and 4 is an image forming section for forming a predetermined image on a sheet in an electrophotographic process section, and is a charger 4a for charging the photosensitive drum 4c and an image such as an original image. A short focus image forming element array 4b for forming information on the photosensitive drum 4c, and a developing device for developing a latent image on the drum 4c.
4d, a cleaning device 4e, a transfer discharger 4f, a separation discharger 4g, and the like. Reference numeral 5 is a belt-shaped sheet conveying mechanism, in which a belt 5a is suspended on pulleys 5b, 5c and 5d.
Reference numeral 6 denotes a fixing roller for fixing the image formed on the sheet by the electrophotographic process section 4. Further, 7 is a conveying roller, and 8 is a sheet branching device, which rotates about a shaft 8a between a solid line position and a two-dot chain line position in the figure to switch the sheet conveying direction. Reference numeral 9 is a conveyance roller.

A is a double-sided conveying device as a conveying means, and the whole device is rotatably supported by a shaft 19 with a bearing. And 10
Is a conveyance roller, and 12 and 13 are pulleys, which form a belt-shaped conveyance mechanism having a belt 17 on the outer periphery thereof. Furthermore, 11 ・ 14
Denoted at 15 are pressing rollers supported on the upper guide plate 16a by leaf springs 11a, 14a, and 15a, respectively. The upper guide plate 16a is fixed to a body frame or the like (not shown).
The lower guide plate 1 is attached to the device A so as to face the upper guide plate 16a.
6b is provided. Further, reference numeral 18 is a protrusion protruding to the rear of the carrying device A. Then, the transport roller 10 and the pulley 12
The belt 13, the belt 17, the lower guide plate 16b, and the protrusion 18 are integrally attached to the frame body 40 of the apparatus A. Further, 20 is a conveyance roller, which discharges a sheet to an intermediate tray B described later.

Further, B is an intermediate tray for temporarily storing the paper on which the image is formed on the first surface of the image processing unit 4. Reference numeral 21 is a regulation plate that regulates the width direction of the paper, and is formed in a vertical shape at two left and right (front and rear in the figure) positions in the paper conveyance path. 22 is a push-up roller fixed to the intermediate tray B to push up the transport device A. Further, 23 is a protrusion fixed to the intermediate tray B. This intermediate tray B has a central axis
It is supported by a main body frame and the like (not shown) so as to be rotatable around 36. An extension plate 24 is rotatably supported by a central shaft 37, and its tip is supported on the projection 23 of the intermediate tray B by its own weight. In this embodiment, the intermediate tray B as the main intermediate placing means and the extension plate 24 as the auxiliary intermediate placing means form an intermediate placing portion. Further, 27 is a release lever, which is rotatable around a central shaft 28 and pushes up and supports the intermediate tray B to a predetermined position. Reference numeral 29 denotes a re-feeding device as a delivery unit that separates the sheets 38 stacked on the intermediate tray B and the extension plate 24 as an intermediate loading section one by one and re-feeds them to the process section 4.

Further, reference numerals 30, 31, 32 and 33 are for guiding the sheet re-fed by the conveying roller to the registration roller 3 again. 34 more
Reference numeral 35 denotes a discharge / conveyance roller which receives a sheet on which images are formed on both sides or one side of the sheet. Numerals 25 and 26 are stoppers for restricting the rotation of the double-sided conveying device A or the extension plate 24 when the conveying path is opened. This extension board 24
If the size of the paper 38 loaded on the intermediate tray B is large,
It serves as a support for the paper 38 and substantially functions as part of the intermediate tray.

In the figure, 42 is a document table, O is a document, and 43 is a pressure plate. Further, 44 is an illumination lamp, and the image of the document on the document table 42 is
The document table 42 is irradiated by being reciprocally moved.

Next, the operation of this embodiment will be described.

The paper 1 in the cassette 1a is fed by the rotation of the paper feed roller 2, and the registration roller 3 corrects the skew of the paper,
Adjust the timing with the image on 4c. Next, an image corresponding to image information such as an original image is formed on the first surface of the paper in the electrophotographic process unit 4, and the drum is separated by the separation discharger 4g.
The sheet separated from above 4c is sent to the fixing roller 6 by the belt-shaped sheet conveying mechanism 5 and the image is fixed. Next, the sheet having the one-sided image formed thereon is deflected by the branching device 8 located at the two-dot chain line position, and is stacked on the intermediate tray B through the transport rollers 9, 10, 12, 13, 20 and the upper and lower guide plates 16a, 16b. To be done. After the image forming process for the first side is completed, the sheets stacked on the intermediate tray B or extending over the extension plate 24 are separated one by one by the re-feeding device 29 and re-fed. The half-moon rollers 29a and 29b rotate in the direction of the arrow to re-feed the paper on the intermediate tray B in cooperation with the re-feed device 29. The re-fed paper advances to the reversing path 45,
It is sent to the registration roller 3 at 30, 31, 32, and 33, and the skew of the paper is corrected again and the timing is adjusted. Next, in the paper whose front and back are reversed, an image corresponding to image information is formed again on the second surface of the paper by the electrophotographic process unit 4, and the belt-shaped paper transport mechanism 5 sends the image to the fixing roller 6 and the second surface of the paper. The image is fixed.

Then, the paper is ejected out of the machine by the conveyance rollers 8.34 and 35, and the series of double-sided image forming steps is completed.

In the case of single-sided image formation, the sheet on which the image is formed on the first side is discharged by the branching device 8 located at the solid line position.
Guided in the directions of 34 and 35 and discharged outside the machine.

Next, the releasing operation of the transport mechanism when the paper is jammed will be described.

FIG. 2 is a sectional view showing a state in which the transport mechanism is released.

As shown in the drawing, first, when the release lever 27 is tilted counterclockwise, the intermediate tray B rotates around the shaft 36 counterclockwise and descends. As a result, the protrusion 23 also lowers, and in conjunction with this, the extension plate 24 pivots clockwise about the shaft 37 and lowers to hit the stopper 25. Also, intermediate tray B
By lowering, the push-up roller 22 also lowers, so that the carrying device A pivots counterclockwise about the shaft 29 and lowers, hitting the stopper 26 and stopping. To return from the jam handling state to the operating state, rotate the release lever 27 in the clockwise direction to return to the state shown in FIG. 1, and each mechanism will rotate in the opposite direction. Activated.

In this way, only by operating the release lever 27, the division opening of the intermediate tray B and the division opening of the double-sided conveying device A can be performed simultaneously. Therefore, the intermediate tray B
The paper inside and the paper inside the transport device A can be removed at the same time. Further, since the intermediate tray is substantially divided and released, the entire apparatus is miniaturized while performing the same function as that of the intermediate tray originally shown by the chain double-dashed line.

Furthermore, to explain the advantages in detail, since the intermediate mounting portion is divided and can be opened, a wide space is not required when lowering the intermediate mounting portion for jam clearance or the like, and therefore the device can be downsized. Moreover, if both are pivotally supported and the extension plate 24 is restrained by the intermediate tray B, the extension plate is also lowered only by lowering the intermediate tray, and the operation is easy. Since a space is also formed between the intermediate tray and the extension plate, the jam processing is further facilitated, and the extension plate and the intermediate tray are divided and opened in a double door shape, so that the jam can be sufficiently jammed even in a narrow space. Space is reserved for processing.

In addition, the upper re-feeding device 29 is interlocked with the lowering of the intermediate placing portion.
Also, even if a jam occurs in the re-feeding device, the processing can be easily performed through the opening part of the intermediate mounting part. In particular, if the both are pivotally supported at the same direction end and lowered in the same direction, the jam processing becomes easier.

Although the electrophotographic process unit is shown as the image forming unit in the above embodiment, the present invention is not limited to this, and other known image forming processes can be applied. Further, the intermediate mounting portion is not limited to the combination of the intermediate tray and the extension plate shown in the embodiment, but may have a box-shaped configuration or the like. Further, the sheet is not limited to paper, and may be a plastic thin plate or the like.

〔The invention's effect〕

As described above, according to the present invention, there is an effect that a larger size sheet can be used if the entire apparatus can be downsized or have the same size. Furthermore, the operability of the jam treatment can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a double-sided image forming apparatus to which an embodiment of the present invention is applied, and FIG. 2 is a sectional view showing its released state. In the figure, A ... double-sided transport mechanism, B ... intermediate tray 27 ... release lever, 24 ... extension plate 23 ... protrusion, 25 ... stopper

Claims (2)

[Claims] 1. A double-sided image forming apparatus for forming an image on both sides of a sheet, wherein an image forming section for forming an image on the sheet and a sheet on which the image is formed on the first side of the image forming section are temporarily placed. An intermediate placement part that can be divided and opened, and a feeding means that feeds the sheet from the intermediate placement part to the image forming part again to form an image on the second surface of the sheet. The placing portion is capable of placing the main intermediate placing means movable in the vertical direction and the sheet protruding from the main intermediate placing means, and is movable in the vertical direction separately from the main intermediate placing means. An auxiliary intermediate placing means, the main intermediate placing means is pivotally supported at one end remote from the auxiliary intermediate placing means, and is restrained by the releasing means at the other end, and the operation of the releasing means is performed. Swings up and down by the It is rotatably supported at the end farther from the main intermediate placement means, and is restrained by the main intermediate placement means at the end nearer when the main intermediate placement means is in the upper position. Characteristic double-sided image forming apparatus. 2. A double-sided image forming apparatus for forming an image on both sides of a sheet, wherein an image forming section for forming an image on the sheet and a sheet having an image formed on the first side by the image forming section are once placed. For separating and opening, and a sending-out means for sending the sheet from the intermediate stacking section to the image forming section again to form an image on the second surface of the sheet, and vertically separable A pair of upper and lower sheet conveying means, which is above the intermediate placing portion and which guides the sheet on the first surface of which the image is formed on the first surface to the intermediate placing portion. However, the intermediate placing section is capable of placing a main intermediate placing means movable in the vertical direction and a sheet protruding from the main intermediate placing means, in the vertical direction separately from the main intermediate placing means. Equipped with an auxiliary intermediate mounting means that is movable to The main intermediate placing means is rotatably supported at one end far from the auxiliary intermediate placing means, and is restrained by the releasing means at the other end, and swings up and down by the operation of the releasing means. The intermediate placing means is rotatably supported at the end farther from the main intermediate placing means, and is restrained by the main intermediate placing means at the end nearer when the main intermediate placing means is in the upper position. The lower sheet conveying means of the conveying means is pivotally supported at one end, and is restrained by the intermediate placing portion at the other end when the intermediate placing portion is in the upper position, and the intermediate placing portion is A double-sided image forming apparatus, characterized in that when the unit is in the lower position, it is held in the divided position by being restrained in the lower position by another stopper means.