Source: {"pile_set_name": "USPTO Backgrounds"}

1. Field of the Invention
The present invention relates to a cover of an image forming device such as a printer, a facsimile machine, and a copy machine.
2. Description of the Related Art
Japanese Utility Model-Application Publication No. HEI-7-2345 discloses a document scanning unit with a tray serving both as a supply tray for supplying documents to a document retrieving portion, and as a document-discharge tray for receiving the documents after images are retrieved.
The device case is formed with a sheet-supply port through which documents are supplied into the device, and sheet-discharge port through which documents are discharged out of the case. The sheet-supply port and the sheet-discharge port are formed in the rear and the upper sides of the case, respectively, so as to sandwich therebetween the rear upper portion of the case. The tray is mounted at the rear surface of the case and includes a slanting surface that slants downward toward the sheet-supply port. A guide is provided on one edge of the upper surface of the tray. The guide is for regulating size of documents placed on the tray.
The guide includes a regulating rib extending in a direction substantially parallel to the surface of documents stacked on the tray. Documents to be supplied into the document retrieval device are stacked on the tray below the rib and documents are discharged out of the discharge port on top of the rib. In this way, the rib separates sheets to be supplied from sheets that have been discharged.
Japanese Patent-Application Publication (Kokai) No. HEI-8-177297 discloses a mechanism for pivoting open a cover of a printer and slowly stopping the cover when the cover opens to a desired amount. The disclosed mechanism requires only a slight force to move the cover when first pivoting the cover open, but a larger force as the cover opens wide.
The cover is pivotably mounted on a shaft that is fixed to the device case. A coil spring is compressingly wound around the periphery of the shaft. When the cover is pivoted open, a free end of the coil spring engages with the cover so that the coil spring unwinds around the fixed shaft in a direction for loosening the coil spring. Force required to move the cover increases the more the cover is opened, because force required to unwind the coil spring increases.
Japanese Utility Model-Application Publication No. HEI-8-878 discloses a mechanism for stopping a cover at a desired opened position. The mechanism includes a cover, a rod, and a stop member. The rear edge of the cover is pivotably connected to a case so that the cover can be opened up with respect to the case by lifting up the front edge of the case. The stop member is fixed to the cover. The rod is also pivotably connected to the case and extends through the stop member on the cover. A friction member is supported in the stop member. The friction member is designed to move along the rod without generating any friction resistance while the cover is being opened, but to engage with the rod by friction while the cover is being closed.
However, with the configuration disclosed in Japanese Utility Model-Application Publication No. HEI-7-2345, supplied documents and discharged documents travel in opposite directions. Because the guide is provided only at one edge of the tray, discharged and supplied documents will rub against each other at the edge without the guide. There is a potential problem in that documents that have already scanned and then discharged from the retrieval device will get drawn back into the retrieval device by movement of documents being supplied. These documents will again be supplied back to the retrieval device and rescanned so that sheets that have been processed can be mixed in with sheets that have not yet been processed. Also, when discharged documents reenter the sheet-supply port in this manner, they can enter the sheet-supply port at an angle and cause paper jams, or can be torn or otherwise damaged.
The mechanism described in Japanese Patent-Application Publication (Kokai) No. HEI-8-177297 requires the coil spring to be wound around the fixed shaft. Therefore, assembly of the mechanism is extremely troublesome. When the cover is heavy, the coil spring must be formed from a thick diameter wire or other thick material, and also must be lengthened. As a result, a fairly large area must be secured to accommodate the lengthened and thickened coil spring around the fixed shaft. Therefore, the mechanism for opening and closing the cover must be relatively large.
The mechanism described in Japanese Utility Model-Application Publication No. HEI-8-878 requires a long rod extending from the case to the cover. Also, the rod pivots in a fan shaped motion in association with opening and closing of the cover. Other components can not be disposed along the pivot orbit of the rod. In other words, the mechanism for opening and closing the cover takes up a lot of space. Also, troublesome operations are required to attach the components of the mechanism together.
It is an objective of the present invention to overcome the above-described problems and to provide a device for supplying and discharging sheets in an image forming device wherein supplied sheets and discharged sheets are not supplied at a slant and do not get mixed up, and to provide a mechanism for opening and closing a cover with a compact shape that can be assembled with easy operations.
One aspect of the present invention relates to devices that supply and discharge sheets to almost the same location following a U-turn pathway. According to this aspect of the present invention a sheet supply/discharge configuration includes a case and a sheet-supply tray. The case is formed with a sheet-supply port and a sheet-discharge port extending substantially in parallel with each other.
The sheet-supply tray includes an upper surface, a pair of guides, and a pair of separation ribs. The upper surface slants downward toward the sheet-supply port and has a lower edge disposed with the sheet-supply port interposed between the lower edge and the sheet-discharge port. The pair of guides is disposed in an upright posture with respect to the upper surface. The guides guide sheets stacked on the upper surface toward the sheet-supply port. The pair of separation ribs are provided one to each of the guides. The separation ribs together define thereabove a sheet-discharge pathway and therebelow a sheet-supply pathway.
With this configuration, sheets can be supplied from and discharged to almost same place without the two types of sheets getting mixed up. That is, even if the recording sheets are supplied through the sheet-supply pathway in a direction completely opposite from a direction in which the recording sheets are discharged through the sheet-discharge pathway, the separation ribs prevent sheets being supplied and sheets being discharged or that have been supplied and discharged from touching each other. Therefore, discharged sheets can be prevented from being drawn back into the sheet-supply pathway by sheets being supplied. As a result, the discharged sheets can be prevented from being printed on for a second time. Also, paper jams can be prevented. Because this function is achieved by providing only a pair of guides in the upper surface of the sheet-supply tray, the configuration is extremely simple.
It is desirable that the sheet-supply port and the sheet-discharge port be formed in an upper surface of the case. In this case, it is desirable that a regulating protrusion be formed on the upper surface of the case at a position between the sheet-supply port and the sheet-discharge port. The regulating protrusion guides sheets from the discharge port to travel above the separation ribs of the guides.
With this configuration, the restriction protrusion prevents discharged recording sheets from entering the sheet-supply port below the pair of guides, as the discharged sheets pass over the upper surface of the case. As a result, discharged recording sheets can be more reliably prevented from entering into the sheet-supply side.
It is also desirable that each separation rib has a slanted surface slanting nearer the upper surface with increasing proximity to the sheet-supply port. Because the separation ribs are higher at the side through which sheets are introduced in between the guides and into the sheet-supply pathway, a plurality of recording sheets can be more easily inserted in between the guides. Additionally, because the recording sheets are discharged by sliding upward across the upper surface of the separation ribs, the front edge of the recording sheets are more greatly separated from the supply pathway with increasing distance from the sheet-supply port, that is, with increasing proximity to the side through which sheets are introduced into the sheet-supply pathway. Therefore, recording sheets that move downward when supplied are less likely to contact discharged sheets or sheets that are being discharged. As a result, the discharged sheets are less likely to be drawn into the sheet-supply port by sheets being supplied.
It is further desirable the sheet-supply tray be pivotably mounted on the case and pivotable into a posture covering at least the sheet-supply port. In this case, it is further desirable that an extension hopper be pivotally mounted on the upper surface of the sheet-supply tray so as to be pivotable between a reclining posture and an extended posture. In the reclining posture, a substantial portion of the extension hopper is adjacent to the upper surface. IN the extended posture, a substantial portion of the extension hopper extends off upper surface.
With this configuration, the sheet-supply tray is pivoted open with respect to the case, and then the flat wire shaped extension hopper is pivoted so that its front end sticks out from the free end of the sheet-supply tray. Even if long sheets are stacked on the inner surface of the sheet-supply tray across the extension hopper, the edge of sheets sticking over the free end of the sheet-supply tray do not bend or crease. Furthermore, the end portions of recording sheets