US3072026A - Automatic contact printers for electrostatic reproductions - Google Patents

Description

Jan. 8, 1963 H. MACKRODT 3,072,026

AUTOMATIC CONTACT PRINTERS FOR ELECTROSTATIC REPRODUCTIONS Filed March 13, 1959 2 Sheets-Sheetl F/Gf1 20 22 14 14a 32 I 3 23 1a 26 5 .J I I .I

19 T I J INV ENT OR. HELMUT MACKRODT dim M121;

TORNEYS United States Patent r 3,072,026 AUTOMATIC CONTACT PRINTERS FOR ELECTRO- STATIC REPRODUCTIONS Helmut Mackrodt, Bonn, Germany, assignor to Messrs.

F. Soennecken, Bonn, Germany a corporation of Germany Filed Mar. 13, 1959, Ser. No. 799,306 Claims priority, application Germany Mar. 18, 1958 7 4 Claims. (Cl. 95-1.7)

The present invention relates to an automatic contact printer for electrostatic reproductions, in which all devices for loading, exposing, colouring and fixing are combined in one apparatus.

With the prior known apparatuswhich operate by similar processes, the separate working steps have generally to be carried out independentaly of one another and different copying plates likeswise have to be made separately.

3,072,026 Patented Jan. 8, 1963 slots and bends in the guide ducts permit a friction-less travel of the paper webs.

Adjustable high voltage charging devices are installed in the supply ducts for the electrostatic photographic paper and the print supports. By changing their spacing, the charging process can be adapted to the particular ambient conditions such as air humidity and paper qualities. A trough-shaped container which isfilled with a suflicient quality of toning agents which are known per se is provided for the development or colouring of the charged and exposed separate sheets or paper webs. This and fixingmay be maintained or even interrupted at will as required, by taking suitable measures when producing the electrostatic reproduction. Furthermore, originals or subjects printed onone or both sides or even provided with script and or drawings, etc., can be processed in the automatic printer of the present invention by the transmitted light process or by the reflex process. This is possible as the light-pervious printing cylinder may be swivelled as desired, such as through an angle of 180", while keeping the same supply and delivery devices for both the subjects or originals to be transferred and also forthe electrostatic photographic paper. The direction of rotation of the entiresexposure device is automaticelly adapted to the necessary working method.

By this means, one-sided transparent originals or copies are guided along on the exposure cylinder while, with a swivelled exposure device, the electrostatic or electrophotographic paper travels along the said cylinder and thus reflex copies can be produced.

Long supply and discharge ducts ensure the correct registry and the smoothpassage of the separate sheets. By means of the blocking and deflecting slides fitted into certain of the supply and discharge ducts, it is possible for a sheet of the electrostatic photographic paper only to be statically charged without exposing. While this is being done the exposure means is switched oil and the exposure is subsequently effected outside the apparatus. In this way a reproduction of for example one page of a' book or. the like may be made using the statically charged electrophotographic paper, the sheet of the electrostatic photographic paper exposed outside the apparatus being introduced through a second slot into the apparatus where it is developed and fixed.

In order to be able exactly to cover the sheets of the said photographic paper with the copying originals, a clocking means is arranged on the feed means. This blocking means is so combined with the feed rollers that an automatic advance of the separate sheets, which are supplied, takes place only when a mechanical or electrical actuation of the'feed rollers simultaneously causes the disengagement of the blocking means.

The apparatus can also be provided with a supplementarydevicewhich permits papersin roll form to be used for electrostatic photographic paper and print supports instead of single sheets. In this case deflecting and sliding rollers which are provided at the inlet and outlet container is so designed that the papers which are to be coloured, slide with their uncoated backs along the wall of the container, and are positively supplied for the necessary additional working steps due to the curvature of the container Wall. Arranged in the container itself is a bladed wheel which constantly circulates the toner and' throws it simultaneously on to the surface of the paper web which is to be coloured. The flanges of the bladed wheel project beyond the external diameter of the blades and serve simultaneously as guides for the paper sheets or webs.

current source. The polarity is so chosen as to be opposite to that of the charging voltage, which was used prior to the exposure process, in order to guarantee a better adhesion of the powder elements to the exposed areas. The entire trough-shaped container can easily be extracted from the apparatus housing in order to clean and render possible a rapid replenishment with toner.

Ribs are provided on the inside wall of this trough-shaped trostatically adhering powder particles are thereby firmly fused thereon so that they cannot be wiped off. Electrical heating means are also installed in the supply ducts for the paper sheets or webs, which means can be switched;

on if for example too high a degree of air humidity makes it necessary for the papers to be initially dried in other to produce good electrostatic reproductions.

The complete automatic contact printer with its guide ducts is assembled from components which can easily be removed, so that they can be very quickly cleaned and access to the mechanical parts of the apparatus is assured in simplest possible manner.

In order to facilitate the operation and control of the separate working steps, the complete apparatus is constructed in the form of a desk, so that all supply and discharge slots can be easily supervised.

Arranged at the supply slots of the guide ducts are signal lamps which are so connected that with the different working methods for reflex and transmitted light prints, the only slots used for each particular method of working are those indicated by illumination with the lamps.

The invention is represented diagrammatically and in principle in the figuresof the accompanying drawings. Details of the drive means for the electrical devices are omitted for clarity in the drawings. a FIGURE 1 is a longitudinal section through the automatic printer for using separate sheets,

FIGURE 2 shows a section through the ribs of the printer of FIGURE 1,

This bladed wheel is advantageously made of metal and connected to the terminal of a high voltage FIGURE 3 shows the pair of feed rollers with the paper stop when in the disengaged position,

FIGURE 4 shows the same as FIGURE 3, but in the engaged position, a I t FIGURE 5 shows the automatic printer with a means for handling paper in roll form.

The automatic machine consists essentially of the housing 1, which is composed of a plurality of readily detachable components. However these are not shown as such inorder to simplify the drawings. The electrostatic photograp'hic paper Iis inserted into the slot 2, and the originals or subjects to be printed II are inserted into the slot 3. The paper and the original are both advanced until they abut against the stop 4 of the feed means, which consists of the rollers 5 and 6. The feed means, which is shown in detail in FIGURES 3 and 4, consists essentially of the fixedly mounted roller 5, the movable roller 6, the roller support 7 and the electromagnet 8, Which holds the movable roller 6 away from the fixed roller 5 against the action of a helical spring 9. If now the holding circuit is opened by means of the switch 10, the spring 9 urges the holder 7 carrying the roller 6 downwards, whereby the forks 11 of the holder 7 depress the stop 4 against the action of a spring 12 and the two sheets of paper I and II are driven together and fed to the feed belt 13 which travels around the exposure cylinder 14 by means of the rollers 16, 17 and 18. The electrostatic photographic paper I has meanwhile been electrostatically charged at the high tension station 19. This high tension station consists of an adjustable and substantially U-shaped insulating component 20 slidable in th guideways 21 and 22 the current-conducting wires 23 and also the diaphragm 24, and the grounding rail 25. Depending on the nature of the original or subject to be printed, the print may be made as a reflex copy by the feed means consisting of the belt 13 and the rollers 16, 17 and 18 at the exposure cylinder 14. On the other hand, the print may be made as a transmitted light copy after swivelling the feed means into the lower position, which is indicated in broken lines in FIGURE 1 by the rollers 16, 17 and 18. The light is supplied by the fluorescent lamp 26 which is arranged in the centre of the exposure cylinder 14 and is covered by a screen 14a. The complete exposure means assembly can be rotated about the mean axisinto the position described above, the belt 13 beingautomatically changed over to give the opposite direction of travel. The exposed photographic paper and the original II nowtravel together into the feed means consisting of the rollers 27 and 28 and, after leaving the latter, are separated by a special separating device 29, whereupon the original II discharges through the slot 30 while the photographic paper is introduced through the wall 31 into the trough-shaped developing tank 32 and slides along the wall thereof on the ribs 33, shown in FIGURE 2. The flanges 34 of the bladed wheel 35 take over the lateral guiding action at this point. The bladed wheel 35 circulates the toner (not shown) and throws it against the electrostatically charged and exposed surface of the photographic paper, the powdeiof the oner remains adhering to the paper due to th electrostatic charging. This effect is further strengthened by the bladed wheel 35 advantageously being made of metal and being connected to a voltage source having a polarity opposite to that of the high-tension station 19'. A uniform and economic consumption of the powder is obtained by this circulation of the toner. Meanwhile, the print support III or the transfer paper has been introduced into the slot 36 and electrostatically charged at a second high-tensionstation 37. However, this second high-tension station 37 may be omitted without appreciably impairing the method of operation.

Due to the feed device 38, which can be switched on and which is constructed similarly to that shown in FIG- 'URES 3 and 4, the sheet of the print support III is fed by electric control and synchronously with the electrostation photographic paper which has now been introduced. The support III and the paper I is brought into close contact by a pair of rollers 39 and 40, so that the colouring powder adhering to the said paper I is transferred to the copy support III. Due to the guiding direction into the contact rollers 39 and 40 being vertically upwards, all excess powder particles which are not electrostatically combined fall off, so that clear and satisfactory prints are obtained without the hitherto usual beating and stripping devices having to be additionally installed. After leaving the pair of rollers 39 and 40, the two sheets are separated from one another by the separating device 41 and fed out through the slots 42 and 43. Here they slide past a heating means 44 which supplies such a quantity of heat that the colouring powder is fixed by fusion onto the paper so that it cannot be wiped off. This coinpletes the copying process.

In order to be able to carry out the entire working process when the papers have taken up somewhat too much moisture, for example from the ambient air or due to storage, heating elements 45, 46 and 47 which bring the paper being used to the most favourable degree of dryness are arranged in the feed ducts 2, 3 and 36. v

If a reproduction is to be made of the page of a book or of another printing subject which cannot be inserted in the machine, the slide 49 is pushed down into the position shown in broken lines and the electrostatic photo graphic paper I is introduced in the usual way into the slot 2, where it is statically charged in passing through the high-tension station 19' in the manner previously described and is bent around the lower bend of the slide 49 and thus discharges out'from the slot 48. The exposu're can then be made outside the apparatus. For the purpose of developing such a paper, the slide 50 is also pushed down into the position shown in broken lines, the now exposed paper is introduced into the slot 51 and conveyed by the pair of rollers 27' and 28 into the colour medium container 32. At the same time, the print support III is introduced at the slot 36 and is also electrostatically charged by passing through the hightension station 37. By making electrical contact in a manner not shown, the feed is initiated as previously described and the stop of feed means 38 equivalent to the stop 4 of FIGURES 3 and 4 is disengaged, so that once again the print support III travels in synchronisrn with the sheet of electrostatic paper I, which is now coloured. The transfer of the reproduction and the fixing thereof takes place as previously described.

, For working with paper in roll form, the apparatus shown in FIGURE 1 is placed on a roll carrier 52 according to FIGURE 5, which carries the take-up reels 55 and 56 in addition to the supply roll 53 for the electrostatic: photographic paper I and supply roll 54 for the print support III. In addition, guide rollers 57 to 65 are arranged on walls or frames which are not shown and which are: not connected to the roll carrier 52, these rollers 57 to 65 guiding the paper webs and conveying them corresponding to the previously described working operation. The originals or subjects to be printed are supplied at the: slot 3 and discharge at the slot 30. The paper webs for the print support III are introduced into the apparatus. through the slot 36. The working procedure is the same as previously described. Here also, reflex or transmitted light copies can be prepared, according to the nature of the originals or subjects to be printed. It is only the exposure cylinder which has to be turned to the'required position.

By providing feed devices known per se, fully automatic operation can be achieved.

Electric signal lamps (not shown) indicate inall cases the feed slots to be used, so that the incorrect operation is substantially avoided.

Since the subject of the invention has bnly been dealt with diagrammatically and as regards principles, it is of.

course obvious that variations in construction of the details are possible, and thes also come within the scope of the claims.

What I claim is:

1. An electrophotographic copying apparatus including a housing, photographic exposure structure within the housing, a first duct extending from a wall of the housing to a feed zone adjacent the exposure structure, electrostatic charging elements within said duct, a second duct extending from a wall of the housing to a location adjacent the feed zone, feed mechanism in the feed zone connected to receive sheets from both ducts and pass them together along an exposure path where they cooperate with the exposure structure to cause an image on one sheet to be photographically exposed on the other sheet, adjustable diversion structure movably positioned adjacent the feed zone so that it can be inserted in and withdrawn from zone, and a passageway from the feed zone to the exterior of the housing, said passageway cooperating with the diversion structure to cause a sheet moving through the first duct to be deflected through said passageway and out of the housing without being photographically exposed, when the diversion structure is inserted in the feed zone.

2. The combination of claim 1 in which the housing also includes developing mechanism, an additional passageway connects the developing mechanism with the exposure structure for guiding photographically exposed sheets through a developing operation, and a third passageway connects the additional passageway to the exterior of the housing for receiving a sheet that is photographically exposed outside the housing and leading such externally exposed sheet to the developing mechanism.

8. An electrophotographic copying apparatus including a housing, photographic exposure structure within the housing, duct means extending from the external surface of the housing to a feed zone adjacent the exposure structure, the exposure structure having a light-pervious cylinder mounted for rotation around its cylindrical axis and having a lighted interior for photographically exposing sheets that are fed through the duct means and moved along its periphery, said structure also including holding elements connected for mounting adjacent one circumferential portion of the cylinder rotation to hold a pair of superimposed sheets together and move them from the feed zone around the cylinder in one rotary direction so that the lower sheet is against the cylinder and is exposed in a reflex manner in accordance with an original on the upper sheet, the holding elements being swiveled with respect to the cylinder rotation for shifting to an opposed portion of the rotation path for holding and moving a pair of superimposed sheets firom the feed zone around the cylinder in the opposite rotary direction so that the upper sheet is against the cylinder and the lower sheet is exposed in a non-reflex manner in accordance with an original on the upper sheet.

4. The combination of claim 3 in which the holding elements include a belt that is pressed against the cylinder, driving means actuates the belt for rotation with the cylinder, and a receiving passageway opening adjacent the cylinder receives the exposed sheets regardless of which way they are moved around the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,551,582 Carlson May 8, 1951 2,624,652 Carlson Jan. 6, 1953 2,826,168 Grant l Mar. 11, 1958

Claims (1)

1. AN ELECTROPHOTOGRAPHIC COPYING APPARATUS INCLUDING A HOUSING, PHOTOGRAPHIC EXPOSURE STRUCTURE WITHIN THE HOUSING, A FIRST DUCT EXTENDING FROM A WALL OF THE HOUSING TO A FEED ZONE ADJACENT THE EXPOSURE STRUCTURE, ELECTROSTATIC CHARGING ELEMENTS WITHIN SAID DUCT, A SECOND DUCT EXTENDING FROM A WALL OF THE HOUSING TO A LOCATION ADJACENT THE FEED ZONE, FEED MECHANISM IN THE FEED ZONE CONNECTED TO RECEIVE SHEETS FROM BOTH DUCTS AND PASS THEM TOGETHER ALONG AN EXPOSURE PATH WHERE THEY COOPERATE WITH THE EXPOSURE STRUCTURE TO CAUSE AN IMAGE ON ONE SHEET TO BE PHOTOGRAPHICALLY EXPOSED ON THE OTHER SHEET, ADJUSTABLE DIVERSION STRUCTURE MOVABLY POSITIONED ADJACENT THE FEED ZONE SO THAT IT CAN BE INSERTED IN AND WITHDRAWN FROM ZONE, AND A PASSAGEWAY FROM THE FEED ZONE TO THE EXTERIOR OF THE HOUSING, SAID PASSAGEWAY COOPERATING WITH THE DIVERSION STRUCTURE TO CAUSE A SHEET MOVING THROUGH THE FIRST DUCT TO BE DEFLECTED THROUGH SAID PASSAGEWAY AND OUT OF THE HOUSING WITHOUT BEING PHOTOGRAPHICALLY EXPOSED, WHEN THE DIVERSION STRUCTURE IS INSERTED IN THE FEED ZONE.

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