HU181330B - Sheet feeding device particularly for electrophotographic duplicator - Google Patents

Abstract

Paper feeding device of a copying machine, comprising a rotatably driven photo drum, with a copy sheet magazine (2) accommodating a copy sheet stack (9), a feed roller pair (15, 16) spaced from its output end and controlled to adapt to the copying cycle to feed one out of the Copy sheet magazine (2) advanced copy sheet to the photo drum is driven intermittently, and arranged with a over the copy sheet magazine (2), under pressure with the respective uppermost copy sheet of the copy sheet stack (9) for advancing this copy sheet with its leading edge in the roller gap of (still stationary) Zufuehrrollenpaares (15, 16) cooperating feed roller (8) by means of a peripheral control disc (1) having drive means intermittently and in time before the Zufuehrrollenpaar (15, 16) is driven, wherein on the control disc (1) against each other at the two Scope offset toothed-arch segments (3,4) are arranged, of which one toothed-arch segment (3) with a drive pinion (5) of the feed roller (8), and the other dental arch segment (4) with a drive pinion (5) of Zufuphrrollenpaares (15, 16) cooperates, and wherein the copy sheet stack (9) in the copy sheet magazine (2) according to the respective height of the copy sheet stack (9) adjustable from below against the feed roller (8) is pressed.

Description

BACKGROUND OF THE INVENTION The present invention relates to a sheet feeder, in particular for electrophotographic copying machines, which is capable of dispensing stacked sheets (e.g., sheets of paper) one at a time, at an accurate time. Due to its practical design, e.g. can be advantageously used as copier feeders for electrophotographic (xerographic) copying machines.

In the present state of the art, several solutions are known:

Such a solution is described in DE 25 06 534. Here, the inventor's solution consists in lifting a stack of paper from a tray into the tray from below and pushing the so-called tab separator. sarokszeparátoroknak. The axis of the roller pushing the sheets out of the tray performs a movement perpendicular to itself by means of a suitable lever-guide mechanism: at the moment of dispensing, the toothed wheel is rotated in a toothed arc placed on a lever lifted by a guide track. It is. This solution has the disadvantage of requiring a separate spring lifting device to compensate for the deterioration of the sheet bundle, not only to rotate the feed roller shaft, but also to require additional components to move the feed roller pair.

In the case of the dispenser disclosed in DE 29 50018, the feed roller shaft only rotates, but here the lifting of the sheet assembly is performed by a spring mechanism integrated in the tray. The implementation of intermittent rotary motion is very clever, but it requires more components, which makes the whole operation economical.

In the case of circular invention 26,49,673, a central guide wheel moves the roller feed rollers and shafts close to the solution used in our invention, but here again a relatively complicated mechanism is required for tilting the feed roller shaft.

The inventors have developed a device that eliminates the need for a separate device to compensate for a decrease in sheet stacking compared to prior art because it is provided by the tray tilt so that the movement of the metering roller and the conveyor roller is synchronized with a single, well-nailed tooth equipped with a central wheel. The appropriate arrangement of the components, however, ensures that any slippage that occurs when the feed roller is started is compensated by the bulging of the sheet before the transfer roll pair, so that the feed roll pair feeds the sheets at exactly the right time at the desired location (eg electrophotographic).

-1181330

The present invention relates to a sheet feeder, particularly to an electrophotographic copying machine, which feeds sheets separated by a separator of known form into a single sheet stack at a suitable time and speed.

SUMMARY OF THE INVENTION The present invention preferably comprises a feed roller on a geared shaft, a tray storage tray for holding a stack of sheets and clamping the top sheet on a feed roller, a synchronous gear wheel, a synchronous roller pad, and a synchronous gear wheel .

In an operationally advantageous configuration, the sheet storage tray, preferably around the width center of the stack of sheets, is pivotable and is provided with a counterweight to provide a clamping force on the top sheet of the sheet stack.

The invention by way of example! Embodiments of the invention are illustrated in the accompanying drawings and in the following description. The attached drawings show

Figure 1 is an axonometric view of the main elements of the structure of the invention, a

Figure 2 illustrates the accumulation (buffering) of the page to compensate for a synchronization error due to a possible slip of the squeegee roller at the moment the synchronous roller is started.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described as follows:

The central control gear 1 is in kinematic relationship with the rest of the machine, which ensures synchronization of paging to other functions. During one operating cycle of the machine, the central control gear 1 performs exactly one complete turn. The central control gear 1 has two gear rails: 2 synchronous gear rails, 3 servo rack sprockets. The feed rack 3 is engaged by a gear 4 on the shaft of the feed roller 5. The synchronous rack 2 is engaged by a synchronous gear 8 on the axis of the upper roller 6 of the pair of synchronous rollers 6, 7. The stack of sheets is located in the tray 9. At the end of the sheet storage tray 9 there is a counterweight 10 which can be tilted about the A-B axis. It clamps the stack of sheets 9 in the tray 9 to the feed roller 5. Separators 11, 12 are provided in the corners of the stack in order to push only the uppermost sheet of the stack of sheets. Several solutions for separators 11, 12 are known, they may be integrated with the tray 9 or, as in the example! in the embodiment, they are independent. The advantage of this latter solution is that it is easier to insert a new stack of sheets into the tray 9 removed from the machine when the separators 11, 12 are not in the way.

The A-B axis of rotation of the sheet storage tray 9 is preferably located in the geometric bisector of the stack of sheets, so that the sheets are only pressed against the feed roller 5 by a substantially constant force determined by the counterweight 10.

The sheets pushed out of the tray 9 are guided by the guide plates 13, 14 between the synchronous rollers 6, 7.

The page feed device according to the invention operates as follows:

After ⁵ 1 centrally controlled wheel departure is 3 Adogató sector gear into engagement with the four toothed wheels, whereby the 5 Adogató roller may push the top sheet of the bundle which átpattanva 10 counterweight 11 szeparátoθ price, and, guided by the 13, 14, guide plates, which is still 6, It is trapped between 7 pairs of synchronous rollers and then accumulates slightly. The accumulation compensates for the delayed start of the sheet due to any slippage of the feed roller 5. Advantageously, the bottom _{15 of the} baffle plate 13 ensures that the sheets are always curved in the same direction. During one revolution of the central control toothed wheel is in contact with the eight synchronous 2 szinkronfogasív pinion such that the 6, 7 at the right moment synchronous roller pair ₂₀ starts the form and transmits it to the desired speed.

As the sheet stack dwindles, the sheet storage tray 9 is inclined at an increasingly steep angle. After serving the last sheet, the opening 15 at the bottom of the sheet storage tray 9 is exposed so that a suitable sensor (e.g., a micro25 switch, a photo sensor) can be used to indicate the consumed amount.

It can be seen from the above that the structure according to the invention performs page feed more favorably than prior art solutions because:

- the movement and synchronization of the synchronous roller pair and the delivery roller are accomplished by a single common element, preferably a segmented gear,

- the feed roller only rotates, so there is no need to tilt the shaft,

- no additional equipment (eg spring lift) is required to compensate for the deterioration of the stack of sheets placed in the media storage tray,

4θ is tilted by the tray,

- synchronized start of the sheet is ensured in all cases, since the timing error due to the sliding of the feed roller is compensated by the accumulation of the sheet (buffer) between the synchronous roller and the feed roller,

- the structure is capable of feeding a bevelled sheet correctly.

Claims (2)

A sheet feed device, in particular for an electrophotographic copying machine, which feeds sheets separated from a stack of sheets separated by a separator (11, 12) of known design, at a suitable timing and speed, characterized in that it has a feed roller (5) on a shaft with a gear (4). , a tray tray (9) for holding a stack of sheets and clamping the uppermost sheet on the feed roller (5), a synchronous gear wheel (8), a synchronous roller bar (6, 7), a feed gear ring (3) connected to a gear wheel (4), and a synchronous gear wheel. (8) has a central control gear (1) provided with an associated synchronous gear (2) and a guide plate (13, 14) for lower and upper 65. -2181330 Embodiment according to claim 1, characterized in that the sheet storage tray (9) is pivotally formed about the width of the sheet stack and the top sheet of the sheet stack is provided with a counterweight to provide a clamping force on the feed roller (5). 10) is provided.