JPH0313483Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of a document reversing device in a document feeder, and in particular to a device that aims to ensure reliable feeding of documents, accurate synchronization control, and cost reduction. It is.

First, the overall outline of a copying machine equipped with an automatic document feeder, which is the basis of the present invention, will be explained with reference to the drawings. FIG. 1 is a side sectional view of the entire copying machine.

In FIG. 1, the entire copying machine is indicated by 1, and this copying machine 1 includes a document table 2 made of transparent contact glass, etc., on which a document is placed during copying work.
, an automatic document feeder provided on the upper part of the document table 2 and indicated as a whole by 3, a lens 5 built in the cover 4 and which moves in the left and right direction in FIG. 1 to change the magnification, and the document table 2. An exposure scanning means 6 consisting of a light source and a mirror moves along the lens 2, and the exposure scanning means 6 exposes and scans the document surface, thereby converting the document image that has passed through the lens 5 into an electrostatic latent image. A paper feeding section consisting of a photosensitive drum 7, a developing device 8 that applies toner to an electrostatic latent image formed on the surface of the photosensitive drum 7 and develops it into a toner image, and one or more paper feeding cassettes 9a, 9b, . . . A conveying path 11 transports the copy paper taken out from the photosensitive drum 7 to the paper discharge tray 10 via the surface of the photosensitive drum 7, and the copy paper to which the toner image has been transferred and peeled off from the photosensitive drum 7 is heated to copy the toner image. The main elements include a fixing device 14, which includes a heat roller 15, a pressure roller 16, and the like, which fix the image on the paper.

On the other hand, the upper surface of the automatic document feeder 3 is covered by a series of covers 17 as a whole, and the automatic document feeder 3 is swung onto the document table 2 of the copying machine 1 by means of a hinge structure (not shown) attached to the cover 17. It is movably attached, and by this opening/closing operation, the document placed on the document table 2 can be manually fed and ejected. Between the belt drive roller 18 provided horizontally within the cover 17 and the drive roller 20 provided on the downstream side of the belt drive roller 18 in the document feeding direction indicated by an arrow 19, there is a wide, white roller. A document conveyance belt 21 is stretched around in an endless manner, and a plurality of pressing rollers 22 for pressing the document conveyance belt 21 against the document table 2 are attached to the intermediate portion thereof. As described above, the belt drive roller 18 located on the upstream side in the document conveyance direction drives the document conveyance belt 21 on the upper surface of the document table 2 of the document conveyance belt 21, which is on the slack side. This is to convey the document smoothly and effortlessly by using the section. Note that if the rollers located on the downstream side in the conveyance direction are driven, the portion of the document conveyance belt 21 that comes into contact with the document becomes the tension side, and the document cannot be conveyed without unnecessarily pressing down on the document. , extremely unfavorable.

Further, on the upstream side of the belt drive roller 18 in the document feeding direction, a registration roller 23,
Document feed roller 24a and document feed start roller 2
5 are provided in this order, and the registration roller 23 consists of a pair of upper and lower rollers that nip and feed out the original. After once stopping the original sent out from the original feeding roller 24a and aligning the original, This is a roller that sends out the original in the direction of the original transport belt 21. The document feed roller 24a has an arcuate notch on its outer periphery and rotates in the document feeding direction, and there is no notch at the bottom that rotates in the opposite direction to the document feeding direction to prevent double feeding. A roller 24b is provided between the rollers 24b and 24b, which separates double-fed originals and feeds and aligns a single original. The original feeding start roller 25 is indicated by a solid line in the figure. It swings up and down from the position shown to the position shown by the two-dot chain line, and is for conveying the document D placed on the document tray 26 in the direction of the document feed roller 24a.

Furthermore, on the downstream side of the document conveyance belt 21, after the exposure of the document is completed, the document sent out by the document conveyance belt 21 is reversed 180 degrees and discharged onto the document discharge tray 30' of the cover 17. A document reversing guide 27 having a substantially arcuate cross section and paper ejecting rollers 29a and 29b are provided for this purpose.

Therefore, when continuous document feeding is performed in such an automatic document feeder 3, the drive source motor (not shown) on the automatic document feeder 3 side is normally driven first, and the document feed start roller 25 is lowered to feed the document. D, the document feed start roller, document feed roller 24a, and double feed prevention roller 24b rotate, and only the topmost document among the stacked documents D is sent out until it reaches the nip point of the registration roller 23. The documents inserted into the machine are aligned. In this way, the document feed roller 24a is stopped again at the position where it has rotated once, and then the registration roller 23 begins to rotate and feeds the document inserted into the nip point in the direction of the document conveyance belt 21. At this time, the document feed start roller 25 is raised, and the notch portion of the document feed roller 24a faces the double feed prevention roller 24b, so that the registration roller 23 feeds the top layer document without resistance. The document D is conveyed to a predetermined copying position by the document conveying belt 21 while being sandwiched between the document conveying belt 21 and the document table 2, and a copying operation is performed at that position.

When the copying operation is completed in this way, the document conveying belt 21 is driven again to send out the document, and the document is supplied to the paper ejection roller 29a provided at the front in the feeding direction, and the leading edge of the document is guided to the arc-shaped document reversing guide. The document output tray 3 provided at the center of the cover 17 is fed to the document discharge roller 29b while being bent along the document discharge roller 27.
Ejected onto 0'. After the originals are reversed in this way, the ejected originals are stacked on the original output tray 30' in the order in which they were stacked on the original tray 26, which makes it easy to organize the originals and copy again. It's convenient. By the way, in the conventional equipment as mentioned above, for the purpose of reducing cost and making it more compact,
It has been proposed to use a common driving source for the document conveying belt 21 and the paper ejection roller. In this case, it is generally considered that the belt drive roller 18, which is the drive source side of the document conveyance belt 21, is interlocked with the above-mentioned paper ejection roller. Since the interlocking mechanism itself is disposed at a considerable distance from the two sides, the interlocking mechanism itself becomes large, which defeats the purpose of making the device more compact.

Therefore, it is proposed that the driven roller 20, which is disposed relatively close to the paper ejection roller, be interlocked with the paper ejection roller.

By the way, the above paper ejection rollers 29a and 2
Reference numeral 9b conveys the sent document along the document reversing guide 27, which has a substantially arcuate cross section, and is therefore composed of a pair of rollers to strengthen the conveying force. It is used to feed out while holding the object. The paper ejecting rollers 29a and 29b are normally a pair of rollers, one of which is a driving roller whose mounting position is fixed, and the other is a subordinate roller which is elastically biased. Generally, the radius of curvature of the document reversing guide 27 cannot be made very large in order to reduce the size of the document. Depending on the bending strength, the document reversing guide 27
Of the pair of paper ejection rollers 29b provided on the ejection unit side, a repulsive force based on the bending strength of the document acts on the roller whose axis is provided on the outside of the guide surface. Like the roller 29a, it is composed of a driven roller biased by elastic force,
When the inner roller and the driven roller 20 of the document conveying belt 21 are linked, the driven roller is pressed outward due to the bending strength of the document.
When the elastic biasing force against the driven roller is small, the outer roller separates from the inner drive roller, reducing the nipping force on the document, and the document whose rear end is pushed by the document conveying belt 21 is The paper will not be ejected and a paper jam will occur.

Therefore, in order to solve this problem, it may be possible to cope with the thick document feeding described above by increasing the pressing force of the outer driven roller against the inner driving roller. If the pressing force against the drive-side roller is increased, on the other hand, when a thin original passes through the original, the original will be wrinkled or damaged, which will impede further copying.

Therefore, the object of the present invention is to provide a document reversing device that has the function of keeping the nipping force of the exit side paper ejection roller constant regardless of whether the document is thin or thick, and which can also simplify and downsize the device. The gist of this is to provide a belt that is endlessly hung between a belt drive roller located upstream of the original copying position in the original transport direction and a driven roller located downstream of the original transport direction. A document reversing guide having a substantially arcuate cross section is disposed on the downstream side in the direction in which the original is transported by the passed document transport belt, and the original after copying is sent out along this document reversing guide, and the original is reversed. In a document feeding device configured to eject documents onto a document ejection tray, an axis of a driving side ejecting roller whose mounting position is fixed is provided radially outside the guide surface of the document reversing guide, and the driving side ejecting roller In addition to elastically pressing the pressing member, the drive-side paper ejection roller is driven by a drive source common to the drive source of the document conveyance belt in conjunction with the driven roller. The present invention provides a document reversing device in an apparatus.

Next, an embodiment embodying the present invention will be described with reference to FIG. 2 to provide an understanding of the present invention. FIG. 2 is a side sectional view of a document reversing device according to an embodiment of the present invention. Note that elements common to those shown in FIG. 1 will be described using the same reference numerals.

In FIG. 2, reference numeral 27 denotes a document reversing guide having a substantially arc-shaped cross section, which is provided on the downstream side of the document transporting belt 21 in the conveying direction, as described above.
However, there is also a pair of paper ejection rollers 29 on the ejection side.
b is provided. The paper ejecting roller 29b is composed of a driving side ejecting roller 30 and a driven side ejecting roller 31. The driving side ejecting roller 30 is fixed to a drive shaft 32 which is the axis thereof, and this drive shaft 32 is connected to a document reversing guide. The driven roller 20 of the document conveying belt 21 is located radially outward from the guide surface of the document conveying belt 27.
It is actively driven in synchronization with the driven roller 20 by a belt 34 stretched between the driven roller shaft 33 and the driven roller shaft 33 to which the driven roller 20 is attached. Further, a driven paper ejection roller 31, which is a type of pressing member, is rotatably attached to a shaft 35 provided parallel to the drive shaft 32 and radially inward from the guide surface of the document reversing guide 27.
The shaft 35 is connected to the drive shaft 32 by a spring 36.
By being biased in the direction of , the driven-side paper ejection roller 31 is pressed against the drive-side paper ejection roller 30. The driven paper ejection roller 31 can also be replaced by a pressing member such as a leaf spring pressed against the drive side paper ejection roller 30.

Regarding the supply side paper ejection roller 29a, a driving side paper ejection roller 37 is provided on the radially inner side of the guide surface, and a driven side paper ejection roller 38 is pressed on the radial outer side of the driving side paper ejection roller 37. Since the paper is actively fed out by the paper belt 21, paper jams do not occur at the paper discharge roller 29a.

When a copying operation is completed in the above-mentioned apparatus, the document conveyance belt 21 is driven and the driven roller 20 rotates in order to eject the document. Along with this, the driven roller shaft 33 also rotates, and this rotation causes the belt 3 to rotate.
4 and 39 to drive side paper ejection rollers 30 and 37
transmitted to. The document sent forward in the conveyance direction by the drive of the document conveyance belt 21 passes through the illustrated guide 41, is supplied to the paper discharge roller 29a on the supply side, and is sent in the direction of the document reversal guide 27. The leading edge of the document that is being fed in this way comes into contact with the document reversing guide 27, the document bends along this, and when the leading edge comes into contact with the outer periphery of the drive-side paper ejection roller 30 on the ejection side, the force due to the rigidity of the document is This acts on the drive-side paper ejection roller 30, but since the mounting position of the drive-side paper ejection roller 30 is fixed, the nipping force caused by the drive-side paper ejection roller 30 and the driven-side paper ejection roller 31 does not decrease. Reliable document feeding continues, and the document is eventually ejected to the document ejection tray 30'.

As described above, the present invention is based on a belt drive roller that is disposed upstream of the document copying position in the document conveyance direction and a driven roller that is disposed downstream of the document copying position. A document reversing guide with a substantially arcuate cross section is provided on the downstream side in the direction in which the original is conveyed by the belt, and the original after copying is sent out along this document reversing guide, and the original is placed in an inverted state on the document ejection tray. In the document feeder configured to eject the document to the document reversing guide, the axis of the drive-side paper ejection roller whose mounting position is fixed is provided on the radially outer side of the guide surface of the document reversing guide, and a pressing member is elastically applied to the drive-side paper ejection roller. In the document feeding device, the document feeding device is characterized in that the drive side paper ejection roller is driven by a drive source common to the drive source of the document conveyance belt in conjunction with the driven roller. Since it is a reversing device, it is possible to adjust the pressing force of the driven side paper ejection roller against the drive side paper ejection roller to a small value. This makes it possible to reliably eject originals without causing paper jams for thin originals or damage to thin originals.

Furthermore, the drive-side paper ejection roller is linked with the driven roller of the document conveyance belt and is shared with the drive source of the document conveyance belt, making it possible to reduce the size and weight of the document feeder and reduce costs. .

Furthermore, by sharing the drive source as described above, the document conveyance belt and the drive-side paper ejection roller are perfectly synchronized, and paper jams and wrinkles of the document are prevented.

Furthermore, when the document conveyance belt and the drive side ejection roller are driven by a common drive source as described above, the document conveyance belt does not stop until the document passes the drive side ejection roller. Since the reversing guide provided with the drive-side paper ejection roller as described above is only an extremely short guide, the time required for the document conveyance belt to run extra is extremely short.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the entire copying machine having a document feeding device, and FIG. 2 is a side sectional view of a document reversing device according to an embodiment of the present invention. Explanation of symbols, 18... Belt drive roller, 20
...Followed roller, 21...Document transport belt, 2
7... Original reversing guide, 30... Drive side paper ejection roller, 30'... Original paper ejection tray, 31... Driven side paper ejection roller.

Claims (1)

[Scope of utility model registration request] The direction in which the document is conveyed by the document conveyance belt, which is stretched endlessly between a belt drive roller placed upstream of the document copying position in the document conveyance direction and a driven roller placed downstream in the conveyance direction. A document in which a document reversing guide with a substantially arcuate cross section is disposed on the downstream side, and the document after copying is sent out along this document reversing guide, and the document is discharged onto the document output tray in a reversed state. In the feeding device, an axial center of a drive side paper ejection roller whose mounting position is fixed is provided on the radial outer side of the guide surface of the document reversing guide, and a pressing member is elastically pressed against the drive side paper ejection roller, and the drive side paper ejection roller is elastically pressed. A document reversing device in a document feeding device, characterized in that a side discharge roller is driven by a drive source common to the drive source of the document conveyance belt in conjunction with the driven roller.