GB2127386A - Withdrawable copy sheet tray - Google Patents

Abstract

A copier is provided with a withdrawable tray holding copy sheets; in order to facilitate correct positioning of the copy sheets in the tray during loading, a retractable sheet registration guide (90) projects into the open side in the withdrawn position of the tray. This guide is automatically retracted out of the sheet path during or following insertion of the tray into the copier, for example by means of stationary cam (95) deflecting a pin (93) causing pivotal movement of arm (92) against the action of spring (91). <IMAGE>

Description

SPECIFICATION Improvements in copiers This invention relates to copiers having withdrawable copy sheet trays from which sheets are fed through an open side.

In such a copier, in order correctly to position the sheets loaded into the copy sheet tray with respect to the feeder by which they are fed from the tray, they need to be located with respect to the open side of the tray.

However, since the sheets are fed through this open side, it must be unobstructed during feeding.

In accordance with the present invention, in order to facilitate correct positioning of the copy sheets in the tray during loading, a retractable sheet registration guide projects into the open side in the withdrawn position of the tray, this guide being automatically retracted out of the sheet path by movement of the tray during or following insertion into the copier. Preferably the guide is springbiassed to its projecting position.

In one embodiment the guide is retracted by engaging a stationary cam during insertion of the tray into the copier.

In another embodiment the tray is withdrawable at right angles to the sheet feeding direction and is also movable, when fully inserted, between operative and inoperative positions, the guide being retracted, preferably by engaging a stationary cam, during movement of the tray to its operative position.

In a further embodiment a copier has two withdrawable sheet trays which are selectively positionable with respect to a common feeder and both of which have retractable registration guides and are withdrawable at right angles to the sheet feeding direction. One of the trays is also movable, when fully inserted, in the direction of sheet feeding between operative and inoperative positions, its guide being retracted during movement of the tray to the operative position. The guide for the other tray is retracted during insertion of the tray into the copier. Both guides are suitably retracted by engaging respective stationary cams during their said movements.In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which: Figure 1 is a schematic side elevational view of a photocopier incorporating the present invention showing the operational elements thereof, Figure 2 is a schematic, exploded perspective view of the sheet tray arrangement, Figure 3 is a partial perspective view of the paper tray arrangement showing the lifting mechanism, Figure 4 is a perspective view of one of the paper trays showing the sheet registration guide, Figure 5 is a scrap view of the paper tray of Fig. 4 showing the registration guide in greater detail, and Figures 6 and 7 are scrap views of an alternative form of sheet registration guide showing it res > ,ctively in its advanced and retracted pitons.

Referring first to Fig. 1 there is shown a xerographic copying machine incorporating the present invention. The machine includes a photoreceptor drum 1 mounted for rotation (in the clockwise direction as seen in Fig. 1) to carry the photoconductive imaging surface of the drum sequentially through a series of xerographic processing stations: a charging station 2, an imaging station 3, a development station 4, a transfer station 5, and a cleaning station 6.

The charging station 2 comprises a corotron which deposits a uniform electrostatic charge on the photoreceptor. A document to be reproduced is positioned on a platen 1 3 and scanned by means of a moving optical scanning system to produce a flowing light image on the drum at 3. The optical image selectively discharges the photoconductor in image configuration, whereby an electrostatic latent image of the object is laid down on the drum surface. At the development station 4, the electrostatic latent image is developed into visible form by bringing into contact with it toner particles which deposit on the charged areas of the photoreceptor.Cut sheets of paper are moved into the transfer station 5 in synchronous relation with the image on the drum surface and the developed image is transferred to a copy sheet at the transfer station 5, where a transfer corotron 7 provides an electric field to assist in the transfer of the toner particles thereto. The copy sheet is then stripped from the drum 1, the detachment being assisted by the electric field provided by an a.c. de-tack corotron 8. The copy sheet carrying the developed image is then carried by a transport belt system 9 to a fusing station 10.

After transfer of the developed image from the drum, some toner particles usually remain on the drum, and these are removed at the cleaning station 6. After cleaning, any electrostatic charges remaining on the drum are removed by an a.c. erase corotron 11. The photoreceptor is then ready to be charged again by the charging corotron 2, as the first step in the next copy cycle.

The optical image at imaging station 3 is formed by optical system 1 2. A document (not shown) to be copied is placed on platen 13, and is illuminated by a lamp 14 that is mounted on a scanning carriage which also carries a mirror 16. Mirror 1 6 is the full-rate scanning mirror of a full and half-rate scanning system. The full-rate mirror 1 6 reflects an image of a strip of the document to be copied onto the half-rate scanning mirrors 1 7. The image is focussed by a lens 1 8 onto the drum 1, being deflected by a fixed mirror 19. In operation, the full-rate mirror 16 and lamp 14 are moved across the machine at a constant speed, while at the same time the half-rate mirrors 1 7 are moved in the same direction at half that speed.At the end of a scan, the mirrors are in the position shown in a broken outline at the left hand side of Fig. 1. These movements of the mirrors maintain a constant optical path iength, so as to maintain the image on the drum in sharp focus throughout the scan.

At the development station 4, a magnetic brush developer system 20 develops the electrostatic latent image. Toner is dispensed from a hopper 21 by means of a rotating foam roli dispenser 22, into developer housing 23. Housing 23 contains a two-component developer mixture comprising a magnetically attractable carrier and the toner, which is brought into developing engagement with drum 1 by a two-roller magnetic brush developing arrangement 24.

The developed image is transferred, at transfer station 5, from the drum to a sheet of copy paper (not shown) which is delivered into contact with the drum by means of a paper supply system 25. Paper copy sheets are stored in two paper trays, an upper, main tray 26 and a lower, auxiliary tray 27. The top sheet of paper in either one of the trays is brought, as required, into feeding engagement with a common, fixed position, sheet separator/feeder 28. Sheet feeder 28 feeds sheets around curved guide 29 for registration at a registration point 30. Once registered, the sheet is fed into contact with the drum in synchronous relation to the image so as to receive the image at transfer station 5.

The copy sheet carrying the transfer image is transported, by means of vacuum transport belt 9, to fuser 10, which is a heated roll fuser. The image is fixed to the copy sheet by the heat and pressure in the nip between the two rolls of the fuser. The finai copy is fed by the fuser rolls along output guides 31 into catch tray 32, which is suitably an offsetting catch tray, via output nip rolls 31 a.

After transfer of the developed image from the drum to the copy sheet, the drum surface is cleaned at cleaning station 6. At the cleaning station, a housing 33 forms with the drum 1 an enclosed cavity, within which is mounted a doctor blade 34. Doctor blade 34 scrapes residual toner particles off the drum, and the scraped-off particles then fall into the bottom of the housing, from where they are removed by an auger.

As shown in Fig. 2, the elements of the copier are carried by a frame 36 and rrl, ptl enclosed by a cover 37 having a front acres door 38, except for the catch tray 32 which protrudes through the side cover. The copier is mounted on castors 36a. The platen 1 3 is covered by a hinged cover 39 which can be raised for access to the platen. The cover 39 may incorporate a semi-automatic document handler by which copies inserted manually at one side are automatically fed onto the platen for copying and then fed off the platen after copying, or an automatic recirculating document handler by which documents arranged in a stack are fed on to the platen one at a time for copying and then returned to the stack after copying.The copier may also have a sorter or finisher arranged to receive copies from the output nip rolls 31 a.

As mentioned above, sheets S may be fed from either the main tray 26 or the auxiliary tray 27. The auxiliary tray is of larger size than the main tray, enabling a wide choice of paper sizes and types to be fed from it. The trays are physically located in the lower part of the machine below the photoreceptor drum 1.

The paper trays will now be described in more detail with reference to Figs. 3 and 4.

The trays are mounted on a tray carriage 40 for delivering paper to the right as seen in Fig. 2. As shown by the broken lines on Fig.

2, the main tray 26 is the upper tray and the auxiliary tray 27 is the lower tray.

The tray carriage 40 is supported entirely by means of vertical ball slides 41, the moving parts only of which are shown in Fig. 3, the cooperating, fixed, parts being mounted on the rear frame of the machine. The ball slides 41 allow the tray carriage to move vertically up and down as will be described in more detail later (with reference to Fig. 4).

The tray carriage 40 consists of a vertical rear plate 42, a left-hand side plate 43, and a right-hand side plate 44. The left-hand side plate 43 carries a box-like container 45 along the upper part of the tray carriage 40, for housing electrical components, including an electric motor. An upper left-hand slide rail 46 and a lower left-hand slide rail 47 are mounted below the container 45, and extend from front to rear of the left-hand side plate 43. The right-hand side plate 44 carries an inner right-hard slide rail 48 and an outer right-hand slide rail 49 which both extend from front to rear of the right-hand side plate 44, and are both at the same height as the lower left-hand slide rail 47.

The main tray 26 comprises a main tray sub-frame 50 and a main paper support tray 51. The main paper tray 51 is mounted for left-to-right sliding movement over the main tray sub-frame 50 by means of a ball slide 52 at the front of the tray, the rear part of the paper tray 51 sliding over Nylon studs (not shown) in the subframe 50. The sub4rame 50 carries, on a downward extension of its left-hand edge, a left-hand slide 53 for cooperation with the upper left-hand rail 46 of the tray carriage 40, and, on a support plate 55, a right-hand slide 54 for cooperation with the outer right-hand rail 49. The rail 49 for the right-hand slide 54, as mentioned above, is at the same level as the rail 48 which as explained below supports a right-hand slide 72 for the lower tray 27.In order to permit sheets to be fed towards the right from the lower tray 27 the support plate 55 is spaced below the base plate 56 of the main tray subframe 50 on extension pieces 57.

The main paper tray 51, which feeds paper to the right, has an upstanding front wall 58 and a left-hand side wall 59. Sheets are registered against front wall 58 by a movable corner piece 60 which is mounted for left-toright sliding movement on a slide 61, which is itself mounted for front-to-back sliding movement on a slide (not shown). On the lefthand side wall 59, an elongated catch member 62 is formed, with an upstanding outer portion that extends from about the midportion to the rear end portion of the side wall 59. The upstanding outer portion of the catch member 62 is for engagement with a notch 63 in a rack 64 that is mounted for sliding left-to-right movements in the container 45.

The rack is engaged by a pinion that is driven by a motor 65. When the main tray 26 is in the 'home' position in the tray carriage 40, i.e. when it has been slid to the rear of the carriage 40 as far as it will go, the upstanding outer portion of catch member 62 engages in notch 63, enabling the motor 65 to drive the paper tray 51 to the left or the right over the base plate 56 which is cut away at the righthand side as seen in Fig. 2 to permit elevation of the tray 26 above the feeder 28 when feeding from the lower tray 27.

In order to prevent the main paper tray 51 from moving to the right other than when it is in its 'home' position, a groove 74 is formed along the right-hand vertical side of the container 45. Groove 74 extends from the front of the container 45 to a point approximately mid-way between the front and rear of container 45, terminating just in front of the rack 64. The upstanding portion of catch member 62 and the groove 74 are arranged such that during withdrawal and re-insertion of the main tray 1, catch member 62 and groove 74 are slidingly interlocked. Once the main tray 26 is fully home, however, catch member 62 has passed completely through groove 74, and is engaged only by notch 63 of rack 64.

The auxiliary tray 27 includes a platform 66 for supporting copy paper sheets between upstanding front plates 67 and a slideable corner piece 68. Sheets are registered against the front plates 67 by moving the corner piece 68 which is arranged for left-to-right sliding on slide 69, which is itself arranged for back-to-front sliding on a slide (not shown). A left-hand slide 70 is carried by a downwardly extending side plate 71 at the left-hand edge of the platform 66, and a righthand slide 72 is carried by a downwardly extending plate 73 mounted inwardly of the right-hand edge of platform 66. Left-hand slide 70 cooperates with the lower left-hand rail 47 of the tray carriage 40, and the righthand slide 72 cooperates with the inner righthand rail 48 of carriage 40.

Referring now to Fig. 4, the mechanism for raising and lowering the tray will be described. The vertical slides 41 cooperate with rails 80 that are secured by angled members 81 to the rear frame 82 of the machine.

Mounted on the rear panel 42 of the carriage 40 are a capstan 83, driven by a motor (not shown) on the front side of rear panel 42, and two pulleys 84, 85. A cable 86 is secured at one end by an anchorage 87 on the machine frame, generally vertically above the highest point reached by the pulley 84. The cable passes around pulley 84, is wound around capstan 83, passes around pulley 85, and is anchored to the machine frame in the same way as the other end. On energising the motor to turn capstan 83, the carriage 40 is elevated or lowered as the cable winds onto or off the capstan.

Copy paper sheets can be fed out from either tray at the choice of the operator. If sheets are to be fed from the main tray, the main paper tray 51 is moved to the right over the main tray sub-frame 50 by means of motor 65. The tray carriage 40 is elevated to bring the top right-hand edge of the stack of sheets in the main paper tray 51 into the feeding position relative to the paper feeder 28. If sheets are to be fed from the auxiliary tray 27, the main tray 51 is moved to the left over the main tray sub-frame 50, and the tray carriage 40 is elevated to bring the top righthand edge of the stack of sheets in the auxiliary paper tray into the feeding position.

In order to change back to the main tray, the tray carriage 40 is lowered, the main tray is moved again to the right, and the tray carriage 40 is elevated again.

When replenishment of either tray is required, the tray in question may be simply pulled out, on its slides, to the front of the machine. This is only permitted once the main tray 51 has been moved fully to the left and the trays have been lowered from the feed position. In order to load paper, the operator will open the front door, which will break the machine interlock (switch 88) and send a signal by way of the machine logic to the motor which elevates and lowers the tray carriage 40. Energisation of the motor will cause the cable 86 to unwind, allowing the trays to descend under gravity until the tray carriage 40 actuates a down limit switch.

When this limit switch is actuated, a signal is sent to the motor 65, causing the main tray 51 to be moved fully to the left. The trays then come to rest, and either one of them can be withdrawn by the operator. The operator will load paper towards the front righthand corner of the required tray, and set the inboard corner piece 60 or 68 to lock the paper in position.

On closing the front door of the machine, the interlock 88 is remade, and on selection of a paper tray, the required tray is moved into the feed position. When the machine is in the standby mode, it is always set to feed paper from the main tray. This is achieved by a time-out feature that resets the machine to the main tray mode if no copies are made within 90 seconds of completing the previous job, A tray interlock system (not shown) is provided to prevent the operator from pulling the trays out of the machine unless they are in the proper position (as described above), or from pulling out both trays together when they are in the proper position.

In order to correctly position the sheets loaded into the paper trays 26 or 27 with respect to the feeder 28 they need to be located with respect to the right-hand side of the tray. However, since the sheets are fed through the right-hand side of the tray, the opening must be unobstructed during feeding.

So as to facilitate the correct positioning of the copy sheets a retractable sheet registration guide member or stop 90 is provided at the front right-hand corner of each tray. Each guide is spring-loaded to its advanced position in which it projects into the open right-hand side of the respective tray so that it will assume this position when the tray is withdrawn thus forming a stop for locating the lead edges of the sheets in the tray. As the tray is moved to its home position, the sheet registration guide is automatically retracted by engaging a stationary cam surface. In the case of the tray 27, retraction occurs during insertion of the tray into the copier but in the case of the tray 26, retraction occurs following insertion as the paper tray 51 is moved to the right over the base plate 56.

Referring now to Figs. 4 and 5, there is shown the registration guide 90 for the tray 27. The guide is formed by an L-shaped piece secured to the front plate 67 of the tray and biassed to the position shown, in which it projects into the paper path, by a leaf spring 91. An arm 92 is pivotally connected to the registration guide and has a pin 93 at its other end which projects through a slot 94 in the base 66 of the tray. The arm 92 and slot 94 extend away from the guide 90 at an angle such that withdrawal of the arm by sliding the pin 93 in slot 94 will cause retraction of the guide 90. This is achieved during insertion of the tray 27 as it comes to its home or fully inserted position by the pin 93 being deflected by a stationary cam 95 arranged beneath the tray 27 on the carriage 40. To produce smooth operation the pin 93 has a rotatable sleeve 93a which engages the cam 95.

Referring now to Figs. 6 and 7, the tray 26 has a guide 90 which is mounted on the paper tray 51. As with the tray 27, the guide is formed from an L-shaped piece secured to the front plate 58 of the tray 51 and biassed to its operative ot advanced position project ing into the paper path by a leaf spring 96.

Retraction of the guide 90 is effected during movement of the tray 51 to its sheet-feeding position on the base 56 by a pin 97 on the guide engaging an angled ram or cam mem ber 38 on the base 56.

During withdrawal of the trays the pin 93 or 97 is disengaged from the respective cam 95, 98 and the guides 90 are advanced so as to project into the paper path by the associ ated spring 91 or 96.

While particular embodiments have been described it will be understood that various modifications may be made to the specific details referred to herein without departing from the scope of the invention as defined in the appended claims.

Thus, although the apparatus described above has two paper trays, it may equally have three or more paper trays. In these circumstances, all the trays except the lower most tray need to be of the kind referred to above as the main tray, i.e. of the kind including a sub-frame and a tray mounted for left-to-right movements across the sub-frame.

Furthermore, the lowermost tray (of any num ber of trays) need not necessarily be of the kind described above as the auxiliary tray. It, too, may be of the same kind as the main tray, with a tray slidably mounted on a sub frame.

Further, while the trays only have a single registration guide at one side of the opening, such a guide may be provided at each side of the opening. Also, while the guides described are retracted sideways such a guide could be retracted downwards below the floor of the tray.

Claims (9)

1. A copier having a withdrawable copy sheet tray from which sheets are fed through an open side thereof, in which a retractable sheet registration guide projects into said open side in the withdrawn position of the sheet tray to facilitate positioning sheets in the tray, said guide being automaticlaly retracted out of the sheet path by movement of the tray during or following insertion into the copier.

2. A copier according to claim 1, in which the guide is spring-biassed to its projecting position.

3. A copier according to claim 1 or 2, in which the guide is retracted by engaging a stationary cam during insertion of the tray into the copier.

4. A copier according to claim 3, in which the tray is withdrawable at right angles to the sheet sheet feeding direction.

5. A copier according to claim 1 or 2, in which the tray is withdrawable at right angles to the sheet feeding direction and is also movable, when fully inserted, in the direction of sheet feeding between operative and inoperative positions, the guide being retracted during movement of the tray to said operative position.

6. A copier according to claim 5, in which the guide is retracted by engaging a stationary cam during said movement.

7. A copier according to claim 1 or 2 including two withdrawable sheet trays which are selectively positionable with respect to a common sheet feeder and both of which have retractable sheet registration guides and are withdrawable at right angles to the sheet feeding direction, one of said trays being also movable, when fully inserted, in the direction of sheet feeding between operative and inoperative positions, its guide being retracted during movement of the tray to said operative position, the guide for the other tray being retracted during insertion into the copier.

8. A copier according to claim 7, in which said guides are retracted by engaging respective stationary cams during their said movements.

9. A copier constructed, arranged and adapted to operate substantially as hereinbefore described with reference to Figs. 1 to 3 and Figs. 4 and 5 and/or 6 and 7.