DE2027550A1 - transfer device for powder images - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann, 2027550

Dipl.-Ing. H. Weickmann, D1PL.-PHYS. Dr.K. Fincke Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, DEN

PO Box 860 820

MÖHLSTRASSE 22, NUMBER 48 39 21/22

XEROX CORPORATION, Rochester, U.Y. 14603, V.StoAo

Transfer device for powder images

The invention relates sioh to a transfer device for from charge images generated by development powder images from an image plate onto a carrier material, with several transferable images can be generated.

With the introduction of electrostatic color copying processes, in which a series of charge images is generated from one original at a time, each charge image corresponding to a specific color of the original, the developed images of such a series must be precisely aligned on a sheet of transfer material. In the case of automatically operating high-speed copier machines and to achieve the flexibility required to transfer a single image or a whole series of images onto a copy sheet, the transfer device must be suitably controlled both for carrying out a single transfer and for transferring several images one above the other.

The object of the invention is therefore θβ, a new transmission device to create that meets the above conditions and works simply and reliably

Ö09850 / 1894

₂ 1027550

- d. - *

Starting from a transmission device of the type mentioned at the beginning Art this object is achieved according to the invention in that a sheet of the carrier material holding and this in a repetitive motion with the image plate Bringing into contact carrier is provided that the carrier has FeBtstelleinrichtungen with which the Sheet is lockable on the carrier and detachable for its removal therefrom, and that one cooperates with the carrier Control device is provided, with which the release of the locking device after a predetermined number images generated by the original can be controlled "

With the help of such a transmission device, in which in easy way of aligning, locking and loosening a sheet of the carrier material on a e.g. as transfers drum-shaped carrier depending on the setting of a control device or < > the powder images that have already been transferred to the sheet are also available with high Color copier machines operate at automatic speeds high-precision alignment and locking of a sheet on the transfer drum prior to image transfer and a Detachment and removal of the sheet from the transfer drum after one or after a certain number of image transfers possible

The invention is illustrated by means of one in the drawing Embodiment explained in more detail 0 Show in detail

Fig. 1 also shows a copier with its different ones Treatment stations,

Figure 2 is an enlarged © © view a © r in r ä © invention applied Ubertragungstromm®! in ®ift®r © ^ stom operating · «■ position ,, whereby some parts® amggebroofo®». SlSa ₉

Figo 3 © ine Sohnittda ^ stisllung d © r ttbertragiaagstroka®! and their storage in aia®r longitudinal masioirtg

009850/1894

20 2 75 5 O '

Figo4 shows a section through the transfer drum at a other operating position,

Figo5 shows a sonitt through the transfer drum, with straight aligning a sheet of substrate

Pig.6 a same view, in which the gripper is just one Grab sheet, and

Figo? a same view just before a sheet of the Transfer drum is stripped.

For a general understanding of what is shown in the drawing The various subassemblies of such a machine are explained with reference to FIG. As with all of them electrostatic process is also shown in the electrophotographic Machine a photo of an original to be copied onto the sensitized surface of an image plate projected in order to generate a charge image on this. Then the charge image is developed into a powder image, which corresponds to the charge pattern. The powder image is then ^ ektrostatisoh transferred to a support surface on which it can be fixed by fusing so that it adhered permanently to this support surface

The machine shown is an original to be copied D arranged on a translucent slide, the is fixedly arranged opposite a lamp assembly 10 at the upper end of the machine. A control circuit of the machine controls a lamp control circuit that has a sequential Switching on the lamps 10 causes the original illuminated and thus light rays of the original are generated, which after passing through the color separation filter of the color information correspond to the original. The Liohtatrahlen are through an optics 11 for exposure of the image plate in the Illumination Bstation A is projected, the image plate being the Has the form of a flexible, photoconductive belt 12, which on

00 9.850 / 189 *.

an arrangement denoted by 13 is mounted.

The belt assembly 13 can be attached to the machine frame and drives the selenium belt 12 at a constant speed in the direction indicated in Fig.1. While moving of the tape, the light rays coming from the original are successively in the form of the entire original on the tape surface flashed ο The tape used uses a layer of photoconductive, insulating material, such as selenium, on an electrically conductive base which is sensitized by a suitable corona charging device 14 before exposure will·

The flash exposure of the strip surface with the light image discharges the areas of the photoconductive that have been struck by the light Layer, as a result of which a charge image remains on the strip with each exposure, which is represented by a corresponding one Parbauaugsfilter given photo of the original D corresponds to «As the belt moves further, the move Charge images through a development station B, in which there is a development unit 15 and the belt is a flat one Web Formed The developing equipment 15 has a plurality of developing devices 16, 17, 18 and 19, each of which contains a different colored developer to develop the charge images individually

The charge images developed one after the other are with the The tape is moved to a transfer station 0 where a sheet of copy paper is synchronized with the tape speed Speed to make a transfer of the developed images. There is a sheet transport in this station in the form of a transfer drum 20, which is a sheet of paper carries and this brings with each transfer process with the belt 12 in a transfer position, which is later will be explained in more detail «From a sheet conveying device 21

009850 / IS »* BADOR ₁ G ₁ NAL

a sheet of paper S is brought into a certain position on the drum 20 in which it is during the image transfer is being held. The transfer of a developed image from the selenium ribbon to the paper sheet is accomplished by an electrical Voltage causes its polarity opposite the triboelectric opposite charge of the developer particles and that is fed to the transfer drum 20 at the point of contact between the sheet and the selenium ribbon when the sheet passed transfer station 0

After the sheet is stripped from the transfer drum 20 it is fed by a sheet feeder 22 into a Sohmelzfixiervorriohtung 23 moves where that developed and on that Sheet transferred powder image is permanently bound »Faoh the fixation is the sheet from the machine to a suitable one external collection point delivered

The above description should be used in the context of this application. suffice to understand the general puncturing of an electrostatic copier.

During the development, each color image in a series or in a pail of a black-and-white reproduction of each of the images exposed with white Idoht on the selenium belt 12 is moved from the development station B to the transfer station 6. In this station, the belt 12 moves around a roller 70, which is one of the three rollers of the belt assembly 13. The transfer takes place at the contact line between belt 12 and drum 20, which serves as a pre-stressed electrode.

The transfer drum 20 is usually held at a distance from the belt 12 by spring force, so that this spring force is only overcome and the drum is pressed against the belt 12 when the control circuit sends a control signal to an electromagnet. Daduroh is how the transmission works

. BATH ORIGINAL

009850/1894

supply drum fail-safe, i.e. in the event of a power failure or a malfunction of the copying machine becomes the transfer drum always moved to the safe position in relation to the very sensitive selenium band. -

The transfer drum 20 has a metal cylinder mounted in two mutually rotatable swivel arms, which has an electrically conductive rubber coating and is connected to a voltage source suitable for image transmission.As shown in FIGS provided, having such elasticity that it undergoes the Bindrüokung or with a slight contact pressure on the tape 12 a very slight flattening in the rubber to improve the image transfer ₀

One end of the cylinder 72 is versohloasen with an end cap 73 which zentrisoh a drive shaft 74 hälto The other end of the cylinder 72 is closed by an end cap 75 having a centrally disposed hollow shaft 76 ₀ The transfer drum 20 is with its two bearing shafts 74 and 78 held suitably so that it is movable into its two possible positions. For this purpose, the shaft 74 is mounted in one end of the arm 77, the other end of which is rotatably fastened to a Well® 78 'with a cover frame 80, the longitudinal axis of which is? Tromm © la © hiQ is parallel * Similarly, it extends the © Walle 76 duroh. ion arm 81 hin »duroh, in whose one Eaä © si® gslagort is'l aai i © s> ä®m arm 77 corresponds to aowi © olsenfalls on Its ¹ ¥ © 11® 78 g <tiag @ rt ia" t "The Maaohin®nrafcuBien 80 is old @ © sto® @ k1s eyagowtaatea lagarplatten 82 Tersefeea ^ iio äi © WqIIq & 3 gasmll ©! From? SsOmmalaohsa and sswr Welle 7 "

'irme 77 and 81

At every Bnäa ä®r Ifell © 83 feofiaaot ii © ii oiaa

ö0lli0 / 1Si4

only one of which is shown, with a lever 86 firmly connected to the nook at one end of the shaft · Both cams 85 influence the adjacent edges 87 of the arms 77 and 81, so that these around their common Shaft 78 can be pivoted with a slight rotation of shaft 83 .. The cams 85 have only slightly inclined Cam surfaces so that the pivoting movement of the arms is only small, but sufficient to cause the drum 20 to move with the belt 12 to bring into contact. A coil spring 88 is clamped between one end of the lever 86 and the machine frame 80, which in the rest state presses the cams 85 against the arms in such a way that the drum is removed from the belt 12 in one direction Position is what is in the pig, 2 a rotation of the Arms 77 and 81 clockwise corresponded

In order to overcome the spring force of the spring 88 and thus the drum 20 for image transfer with the belt 12 in contact To bring an electromagnet SOL-2 is provided that the Shaft 85 rotates against the spring force · The solenoid SOL-2 is connected to the machine frame 80 and has a / ■ -er 90, which can be swiveled with a Vfelle 83 attached Lever arm 91 is connected * As shown in Fig. 4 * is located the lever arm 91 is on the other side of the shaft 83 as the lever 86, so that when the electromagnet SOL-2 is switched on, which causes a downward movement of the armature 90, the spring force of the spring 88 is overcome and the shaft 83 is rotated in a direction opposite to the spring.This requires a counterclockwise rotation of the arms 77 and 81, whereby the drum 20 contacted the belt 12

The transfer drum 20 acting as an image transfer device can be a copy sheet for a single copy or else Align and hold several transfer processes As already described, the original D is exposed three times, to generate a series of three charge images that

0 0 9 8 5 0/1 8.9 h

sequentially developed and made available for transmission. To make a single color copy of the original, the three developed images are transferred individually onto the same copy sheet «

In order to achieve a precise alignment and fixation of a copy sheet on the drum 20, several alignment pads 95 are provided, which are arranged within the drum and can be moved radially in relation to the drum. The openings form a straight line parallel to the drum axis. Each stop has a flat, rectangular shape and has a projection 97 located outside the jacket surface, which moves radially outward from a position inside the jacket surface of the drum into two positions protruding slightly from the jacket surface is movable «. In operation, the leading edge of a copy sheet S contacts the stops 95 directly outside the projections 97 , after which the edge of the sheet is held during its treatment (see Fig. 5).

The radial movement of the stops 95 is made rotatable by a causes shaft 98 mounted within the drum 20, which cooperates with drive levers 100 mounted on the shaft and which slide within openings 101 at the inner end of the Attacks are held. The shaft 98 is rotatably supported in bearing blocks 102 connected to the inner surface of the cylinder 72, so that upon rotation of the shaft 98, the drive levers 100 are pivoted, whereby the stops opposite one another move the drum ear outwards or inwards. During operation, the stops 95 can assume three possible positions: the first position when no sheet is being transported where they take their most inward position; the second position at slightly outwards pushed stops, so that the projections have lifted slightly from the lateral surface, in which a copy sheet, such as

009850/18 94 _BAD ORIGINAL

in Figo5, was aligned, and a third position, in which the projections 97 have a slightly greater distance from the outer surface, around the leading edge of the copy sheet immediately before the blade is stripped from the shell surface of the drum 20, as shown in FIG. 6 isto

Several gripper fingers work together with the stops 95 105, which are connected to the shaft 98 via clamps 106 and which extend through openings 107 which are aligned with the openings 96 within the jacket surface of the drum 20 for the stops 95 are arranged. As shown in Fig.8, When the drum 20 is viewed axially, the fingers 105 and the stops 95 are aligned with one another parallel to the drum lug. A spring 108 between a bracket on the inner surface of the cylinder 72 and a lever 109 connected to the shaft 98 is kept under tension and forces the stops into their furthest into the lateral surface immersed position and fingers 105 in their paper-holding position.

One end of the shaft 98 has a crank arm 110 connected to it that is located within the cap 75 · one with connecting rod connected to one end of the crank arm 110 111 penetrates an opening 112 of the end cap 75 and is connected outside the drum with a lever mechanism that controls the soleplate 95 and the gripper fingers 105 »

The lever mechanism has a first with the upper end of the Arm 81 swivellably connected by a pivot pin 114 belarm 113, a second lever arm 115 so pivotably connected with its one end to the free end of the first lever arm 113 and a third pivotable with its one end with the free end of the second lever arm 115 connected to the lever arm 116 on »The lever arm 116 is at its ends

0Q985O / 1894

connected to a shaft 117 of a rotary magnet SOL-5, which is attached to the arm 81. If the electromagnet SOL-3 is not switched on, a spring located in the electromagnet and not shown here holds the lever mechanism in its position shown in FIG. 3 Positiono When the electromagnet is switched on, the third lever arm 116 is given a clockwise rotary movement, which moves the second lever arm 115 downwards and to the left and thus causes the first lever arm to rotate clockwise around the pivot pin 114. This position of the lever mechanism is shown in Figo2 , whereby the electromagnet S0L «2S is switched on. The pivot pin 114 and the shaft 117 of the electromagnet hold the lever mechanism ₀

A hook surface in the form of a stop 120 is provided on the inside edge of the first lever arm 113 and a similar hook surface 121 is provided on the inside edge of the third lever arm 116. The inside edges of the lever arms 113 and 116 act as cam surfaces, with the stops mainly determining the control of the edges. Each of the stops 120 and 121 interacts in a special way with a driver 122 in the form of a raceway ring connected to the outer end of the rod 111. When the drum 20 rotates, the connecting rod 111 rotates about the drum lug, since the shaft 98 and the opening 112 for the rod 111 also rotate about this axis. During this rotation of the rod 111, it takes the driver 122 with it in a circular movement, the radius of which has its origin in the drum _{eye 8,} as indicated by the letter F in FIGS. 4 and 6 *

In an operating position for the transmission of a one-ness or several pictures with the magnet SOL-3 switched on Movement of the lever mechanism into the position shown in Figo2 the driver 122 presses, see the dashed position, during its rotary movement along the path P against the inner edge of the

009850/1894

Lever arm 116 to the left of shaft 117, which is in the path of the follower, to push rod 111 inward slides along the curve of the stop. Without this stop, if the edge of the lever arm 116 touched, the rod 111 would be accelerated inward at too high a speed for the individual parts of the drum 98 against the force exerted «. The opening 112 is sufficiently large to allow this limited movement of the rod 111. This slight inward movement of the rod 111 causes a slight rotation of the shaft 98, which in turn causes a slight radial movement of the alignment stops 95 at the same time as the leading edge of a copy sheet reaches this, cf. so that, as a result of the magnetic spring, the lever mechanism can assume its position shown in FIG. 4 and the shaft 98 is rotated back into its original position by the spring 108. This movement causes the rod 111 to move outwards when it continues its rotary movement and leaves the inner edge of the lever arm 116. By moving the shaft 98 to its original position, the alignment stops 95 also return to their rest position and the gripper fingers 105 lay the front edge of the Copy sheet, whereby it is held on the drum and transported, VgI ₀ Fig _e 6 «When the drum 20 rotates, this moves the leading edge and also the remaining part of the sheet in the transfer station 0 in order to transfer the developed image onto the sheet to effect. With the further rotation of the driver 122 and the further switched on magnet SOL-3 for a single image

JD 09 8 50/1 89 a

ORIGINAL INSPECTED

transmission presses the driver against the inner edge of the lever arm 113 at the front edge of the stop 120, whereby the rod 111 is moved inward again in a slowing motion by the stop 120 "" The position of the lever arm 113 is such that this inward direction movement of the rod 111 is greater than that by the stop 121 caused. As a result, the shaft 98 is again against the spring force of the spring 108 rotated, with the difference that the 'rotation is slightly greater than when aligning a copy sheet. This additional rotation causes a movement of the gripper fingers 105 that releases the leading edge of the sheet and a additional distance from the edge and also allows the projections 97 of the disengagement stops 95 to cover the leading edge move away from the drum surface «A slight further rotation of the drum moves the leading edge of the sheet over the tips of fixed stripping fingers 130 away, see Pig » 7, whereby the copy sheet is removed therefrom with a further rotation of the drum. As shown in FIG the tips of the stripping fingers 130 when the Grasp protrusions 97 in their outermost position just below the surface of protrusions 97 on which the leading edge rests of the sheet S to be removed from the drum is

Shortly before a copy sheet the drum 20 is fed, the lever arms 113, 115 and 116 having lever mechanism is in its shown in FIG _o 4 position, in which the stops 120 and 121 are arranged so that they nioht during a full revolution with the driver 122 come into contact. If only a transfer is to be made to the copy sheet, for example when black and white copies are made, the solenoid SOL-3 is switched on when a sheet is fed in by the sheet conveyor 21 to bring the inner edge of the lever arm 116 into contact with the driver 122 bring to. After the alignment and detection of the leading edge of the sheet, the electromagnet remains switched on, so that

009850/18 9

the driver acts on the stop 120 to wipe off the sheet again. If, on the other hand, a series with three images is to be transmitted, the electromagnet is quickly switched off after the sheet has been aligned and locked before the driver 122 reaches the lever arm 113. In this case, the sheet cannot be stripped from the drum 20 because the cam surface of the stop 120 is kept out of the path of movement of the driver, so that the sheet remains on the drum until the completion of three transfers, after the last image transfer and passing of the driver 122 at the stop 121, the electromagnet SOIf-3 is switched on again in order to bring the lever mechanism into its position shown in FIG. 2, so that the driver acts on the inner edge of the lever arm 113 the drum stripped, if this continued rotation thereof is the electromagnet SOI-3 is turned on, there are two stops 120 and 121 in the path of movement P of the carrier 122, "is it off against it, are both stops outside this movement path _e in single transmission of Images therefore the electromagnet remains after the alignment and locking of the sheet on the drum e switched on In the case of multiple image transmission, on the other hand, the electromagnet is switched off depending on the orientation of the copy sheet and remains so until the stripping process *

In the automatic operation, another one is used by the sheet feed device 21 given to the drum 20 sheet S of the Stops 95 and the fingers 105 aligned and determined when these the Ausriohtstellung during the further rotation of the drum Reach the drum · The sheet feed mechanism works in automatic cooperation with the transmission streamrael and the Ausrioht- and FestStelleeneinrichtungen and conveys the single sheets in pinch rolls 135, see y ± g.1, dl · the leading edge of the sheet at a greater speed as the peripheral speed of the drum to the drum 20, so that the leading edge of the sheet touch the stops 95

0 0.98 50 / 1-8 9 A.

Claims (1)

202755Q - 14 - Claims Transmission device for of charge images generated by developing powder images from an image plate to a support material, wherein generated aind for generating multi-colored copies of an original plurality of übertragbar® images gekenngeioJmet characterized ₉ characterized in that a sheet of the support material (S) of holding and this in a repetitive " movement is provided with eggs image plate (12)-bringing into contact carrier (20) ₉ äaß the carrier feststelleinrichtung®. "(95, 9S ₉ 105) with which the sheet (S) on ä & m. carrier (20) featstellbar and au its removal from this is releasable "and that a control device (SOIf-3, 113, 115, 116, 122) cooperating with the carrier (20) is provided" with the release of the! locking device (95 ^ 9 © s " 105) can be controlled according to a pre-determined number of images generated from the original (B) 2, transmission device according to claim. 1 * thereby. 'shows that the carrier (20) is holding a sheet (S) © Gripper (105) has α 3 "Transfer device naoh Inspruoh 2, characterized" shows that with the grippers (105) and with a sheet (S) aligning alignment stops (95) during the first functional sequence the sheet (S). It is stated / that during a jsweitea, functional sequence a the. sheet (S) asu its removal from the carrier (20) is detachable, and aai di @ control device (SOIr-J ₉ 113 _t 115 116, 122) temporal sequence of the generation of the first transferable Bilda di® gripper (105) and Ausrientanschlag® (95) in the positions required for the araten functional sequence 009 850/1894 202755Q 4ο transmission device according to claim 3, characterized in that that the control device (SOL-3, 113, 115, 116, 122) according to a predeterminable number of the original produced images the gripper (105) and Ausriohtansohläge (95) controlled into a position required to release the sheet (S) during the second functional sequence 5. Transmission device according to one of the preceding claims, characterized in that a rotatable drum (20) is provided which is held by a pivot device (83, 85) in it he rest position with the image plate (12) out of contact and when switched on with the Swivel device (83, 85) connected drive (SOL-2), the drum (20) can be moved against a force holding it in its rest position, and that the drive (SOL-2) can always be switched on when a transmission to a sheet ( S) is required » Transmission device according to one of the preceding claims, characterized in that a voltage source is provided which can be switched on in a predetermined time sequence and applies a voltage to the drum (20) which has a polarity opposite to the polarity of the charged pulser images. 009850/189