This invention relates to sheet receiving apparatuses for reproducing machines. These devices commonly take the form, for example, of output trays or sorter collators.
There are presently a number of copiers capable of copying on both sides of a sheet, a process known as duplexing. Duplexing may be carried out manually by restacking the copy sheets after copying on the first side, and then placing them in the sheet feeder supply tray for copying on the second side, or it may be carried out automatically by various means as, for example, the use of an auxiliary feeder tray such as in the Xerox "4000" copier.
One of the problems which occurs with many copying machines, as well as other kinds of reproducing machines when they do simplexing which involves imaging on only one side of a sheet or duplexing as above-noted, is the generation of improperly collated sets of copy sheets in the output tray. For simplex copying proper collation can be obtained by properly orienting the output tray so that if sheets 1 through 10 are copied serially in the order 1 through 10, they will appear in the output tray in that order. Similarly, numerous sorter collator type devices have been devised which are capable in a simplex mode of operation of providing properly collated sets of copies.
When one performs duplex copying with the above-noted output tray or sorter the resulting copies of the documents 1 through 10 are improperly collated and appear in the order 2, 1, 4, 3, etc., instead of 1, 2, 3, 4, etc., as desired.
One approach at solving this problem is set forth in IBM Technical Disclosure Bulletin, Vol. 14, No. 5, Oct. 1971, at page 1453. In accordance with the above-noted bulletin a duplexing copier is provided which incorporates a sorter collator which has feed paths which ensure that the sheets having printed matter on one side are deposited in collator bins with the printed matter facing down and sheets having printed matter on both sides are deposited with the last side copied facing up. This is accomplished using a sorter collator having two rows of back-to-back bins. One row for receiving sheets copied on one side, and the other row for receiving sheets copied on both sides. Diverters are used to direct the sheets to the appropriate transports for deposition in the selected row and bin depending on whether they were simplex or duplex copied. While this approach would appear to overcome the above-noted problem, it does so at a substantial sacrifice in space since the two rows of back-to-back bins are required as well as separate transports for each row of bins.
In U.S. Pat. No. 3,638,937, granted Feb. 1, 1972, to Schutz, there is disclosed a collator that can be adapted to accept sheets fed from either of two sides of the collator thus retaining or inverting in the receiver the uppermost side of the sheets as fed to effect a desired sheet orientation in the receiver. While the approach of this patent is more compact than that of the previously noted IBM bulletin, it is not as useful since the machine would have to be turned around in order to change the orientation of the sheets in the bin.
A variety of sorter collator devices have been proposed such as those presented in U.S. Pat. Nos. 3,561,754, granted Feb. 9, 1971, to Gaffron; 3,685,819, granted Aug. 22, 1973, to Deutsch; 3,721,435, granted Mar. 20, 1973, to Zanders, and 3,788,640, granted Jan. 29, 1974, to Stemmle wherein the sorter bins are moved or pivoted to facilitate loading thereof. In each of these devices and other devices of a similar nature, the bins are not moved to change their orientation so as to provide for proper collation of either simplexed or duplexed copy sheets.