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 sticking over the end of the sheet-supply tray do not hang down so that sheet supply can be smoothly performed and distorted printing can be prevented.
When the extension hopper is pivoted from its extended posture between the guides to its reclining or folded condition, the extension hopper will not get in the way when the sheet-supply tray covers the case. Also, the facsimile device can be made more compact.
A second aspect of the present invention relates to a mechanism for opening and closing a cover or other pivotable member of an office automation device, such as a printer, a fax machine, or a copy machine, wherein the cover is pivotable around an imaginary pivot line with respect to a case or other fixed member of the device. This aspect more particularly relates to configuration enabling the cover to smoothly open to a large angle with respect to the fixed member so that the cover opens quietly and without any shock.
According to the second aspect of the present invention, the mechanism is provided to a fixed member and to a pivotable member. That is, the pivotable member is pivotably attached to the fixed member so as to be pivotable about an imaginary pivot line with respect to the fixed member.
The mechanism includes a pin and resiliently deformable slide rib. The pin and the slide rib are provided to different ones of the fixed member and the pivotable member. That is the pin is provided to one of the fixed member and the pivotable member, and slide rib is provided to another of the fixed member and the pivotable member.
The pin protrudes in a direction substantially parallel with the imaginary pivot line. It is also axially centered on an imaginary circle that is centered on the imaginary pivot line. The slide rib has an outwardly-curved surface eccentric with the imaginary circle.
The one of the slide rib and the pin that is provided to the pivotable member is disposed at a position so as to follow the imaginary circle when the pivotable member is pivoted open away from the fixed member. As a result, the outwardly-curved surface and the pin pressingly slide against each other.
With this configuration, when pivotable member pivots open with respect to the fixed member, the pin and the outwardly curving surface will approach each other because, one the one hand, the pin is disposed on the imaginary circle around the imaginary pivot line of the pivotable member and, on the other hand, the outwardly curving surface of the pivot rib is eccentric with respect to the imaginary pivot line.
Said differently, the outwardly curving surface is formed so that one end is nearer the imaginary pivot line than the other end. As a result, when one of the pin and the slide rib moves by pivoting movement of the pivoting member, so that the pin approaches the distant end of the outwardly curving surface, the slide rib resiliently bends in a radial direction with respect to the imaginary pivot line. This bending deformation generates resistance force between the pin and the slide rib so that the moving one of the pin and the slide rib can be stopped and maintained in place with extreme ease. When the pivotable member is massive and heavy, the resistance force against the pin can be easily increased without changing shape or dimensions of the slide rib or the pin itself. That is, to increase the resistance force, the slide rib and the pin need merely be positioned so that the slide rib and the pin abut where the curved surface of the slide rib is further from the imaginary pivot line, that is, in the radial direction from the line. The mechanism having this configuration is compact and does not require large outer dimensions.
It is desirable that when the slide rib has a fixed end and a free end on opposite sides of the outwardly-curved surface, then in this case the outwardly-curved surface slope further away from the imaginary pivot line with increasing proximity to the free end.
By forming the slide rib with one end fixed and the other end free, resistance force for holding the pin in place can be smoothly changed by moving the pin along the slide rib from the fixed end to the free end of the slid rib. As a result, operations for opening and closing the pivotable member can be smoothly performed.
It is desirable that the fixed end of the slide rib be formed integrally with an inner diameter portion of a resin hollow frame. By forming the slide rib integrally to the inner surface of the hollow frame, the slide rib can be positioned by merely fixing a portion of the hollow frame to the fixed member. As a result, operations for attaching the slide rib can be easily performed. Further, because the pivot orbit of the pin is restricted to within the hollow frame, objects can be easily prevented from becoming sandwiched between the slide rib and the pin.
It is desirable that the imaginary pivot line extend in a horizontal direction. Also, it is desirable that the pin be provided to protrude from the pivotable member. Further, it is desirable that the hollow tube frame with the slide rib be fixed to the fixed member. By forming the small pin on the pivotable member, the region where other components can not be disposed because of the pivotable orbit of the pin is reduced so that the device overall can be more compact.
According to a third aspect of the present invention device that uses sheets, such as for printing fax data or print data, includes a lower case, an upper case, a pin, a resiliently deformable slide rib, and a sheet-supply tray.
The upper case is pivotably attached to the lower case so as to be pivotable about an imaginary pivot line with respect to the lower case. The upper case is formed with a sheet-supply port and a sheet-discharge port extending substantially in parallel with each other.
The pin is provided to one of the lower case and the upper case. The pin protrudes in a direction substantially parallel with the imaginary pivot line and is also axially centered on an imaginary circle that is centered on the imaginary pivot line.
The slide rib is provided to another of the lower case and the upper case. The slide rib has an outwardly-curved surface eccentric with the imaginary circle. The slide rib or the pin, whichever is provided to the upper case, is positioned so as to follow the imaginary circle when the upper case is pivoted open. As a result, the outwardly-curved surface and the pin pressingly slide against each other.
The sheet-supply tray is disposed on the upper case at a position to sandwich the sheet-supply port between the sheet-supply tray and the sheet-discharge port. The sheet-supply tray has an upper surface slanting downward toward the sheet-supply port; a pair of guides for guiding sheets stacked on the upper surface toward the sheet-supply port; and a pair of separation ribs provided one to each of the guides, the separation ribs together defining therebelow a sheet-supply pathway and thereabove a sheet-discharge pathway.