LU82011A1 - ELECTROPHOTOGRAPHIC COPYING MACHINE - Google Patents

Description

l! i '1 r! 1! ! j! 5 ELECTROPHOTOGRAPHIC COPYING MACHINE.

The present invention relates generally to electrophotographic copying machines and relates more particularly to an electrophotographic copying machine, usable in particular for forming a table top table and which is characterized, when assembled in a housing, jj 15 by a compact structure and low profile giving rise to a strong reduction in height, while allowing maximum use of the interior space.

! Electrophotographic copying machines include | electrophotographic element which is transported sequentially | 20 in several workstations where a load potential is! applied to the element, the charged element is exposed to a light image projected to form a latent electrophotographic image, a developer is deposited on this latent image, and said developed latent image is transferred to a support.

The support carrying the latent image is discharged, with or without fixing of the developed image, for example by fusion or by a similar process.

The electrophotographic element is in the form of an endless band passing over at least two spaced rollers "30 so as to define two strands parallel and close to each other. Preferably, the loading station, the exposure station and the development station are arranged along a strand placed in a plane coinciding with, or located in a position immediately adjacent to a corresponding plane, or immediately adjacent to the focal plane of the projection system used.

A transfer station is provided and, optionally, an additional work station can also be provided to remove excess developer from the web before the imaging cycle is completed.

2 \

Machines of the general type defined above are known, these machines being large and bulky. In the structures currently available, the different workstations each occupy a considerable space which requires the provision of 5 large casings. Such a bulky structure is not well suited for use on a table top. The measures taken so far to reduce the congestion of these stations have not been satisfactory since measures have been taken consisting in miniaturizing the elements - 10 intervening in said stations, which has resulted materially in: a reduction in the flexibility of use of the machines. In addition, considerable difficulties have been encountered as a result of this miniaturization in the area of machine maintenance. The installation and maintenance of such machines requires particularly experienced operators and this results in considerable downtime for the users of the machines.

It is therefore desirable to have an electrophotographic copying machine which is compact, which has a low profile and in which the space can be reduced while making the most of the available space and minimizing the vertical dimension. without having to involve a miniaturization of the functional elements of the machine.

Consequently, the invention relates to an electrophotographic copying machine with a low profile which is suitable for use as a table top panel and which comprises: a tray for supporting the document to be copied, an electrophotographic strip, a charging station, a station exhibition and development station; a carrier agent supply source and a corresponding 430 training station; an optical projection station directing a bright image of the document onto the electrophotographic strip; and a transfer station for applying the image developed on said carrier agent, as well as a support and drive mechanism for ensuring the drive of the electrophotographic strip consecutively in front of said stations, machine characterized in that the strip is arranged to define two strands oriented horizontally and placed in close proximity to each other, in that the exposure station is positioned on the lower strand between the ends 3 of said strip, in that the projection station optical system comprises a broken line system provided with two spaced beams, said development station being housed between the spaced beams and inside said optical projection station, in that the document-holding plate is oriented in direction of said optical projection system so that the lower strand of said electrophotographic strip is spaced from said plate and is placed essentially at the same level, and in that the entry mechanism also comprises a driving roller which is housed in said development station in order to guide the strip, said source of carrier agent and said training station being placed immediately above the electrophotographic exposure station, about the same level as the document tray.

115 Other advantages and characteristics of the invention will be highlighted in the following description, given by way of nonlimiting example, with reference to the accompanying drawings in which FIG. 1 is a schematic sectional elevation view of the electrophotographic copying machine according to the invention, specially arranged for use as a table top panel; Fig. 2 is a sectional view, on an enlarged scale, made on line 2-2 of FIG. 1.

In the drawings, the electrophotographic copying machine, arranged in accordance with the present invention, has been designated as a whole by 10, its functional elements constituting the work stations being housed in an opaque casing 12. This casing 12 consists of a hollow part 14 in the form of a box 30 and a covering part 16, which is arranged to be mounted on the part 14. The casing part 14 comprises two end walls 18,20, which are fixed to a bottom wall or floor 22, the end walls 18 and 20 respectively comprising vertical extensions 24 and 26.

The cover 16 has two end walls 28, 30, and an upper wall 32. The upper wall 32 is provided with an opening 34 placed near the wall 28 and means are provided around the edges of the opening. 34 for the mounting of a document holder plate 16 which is transparent and 4 preferably situated flush with the wall 32. This plate 16 can be formed from glass or plastic, provided that it is transparent.

A tray cover assembly 40 comprises a cover 5 42, connected along an edge, by means of a hinge 44, to a flat U-shaped element 46. The free edge of the cover 42 has a selvedge 48 directed downwards, this selvedge 1 coming to rest against a corner 52 of the casing cover 16 in order to keep a document closely in position between the plate 36 and the cover 42.

The electrophotographic imaging system, generally designated by the reference 54, is mounted inside the casing 12. An optical projection system, generally designated by the reference 56, is also mounted at 15 inside the casing 12 and below the document tray and the electrophotographic image forming system.

A development station, designated as a whole by the reference 58, is placed between the systems 54 and 56, while a carrier agent supply and drive system 60 is placed above the electrophoto training system. image graphic 54 and that a transfer station 62 is placed in an area adjacent to the system 60.

The electrophotographic imaging system 54 includes an endless electrophotographic strip 62 which passes over two spaced rollers 64, 66, so as to be moved clockwise, i.e. in the direction of the arrows 68, and which defines upper and lower strands 70 and 72 closely spaced from each other.

A guide or alignment roller 74 is placed below y 30 of the strand 72 of the strip 62, near the roller 66.

The strip 62 preferably comprises a conductive substrate 80 on which is fixed a photoconductive coating 78 consisting of a layer of photoconductive material, electrically anisotropic, microcrystalline, completely inorganic and deposited by high frequency electron bombardment, this layer having a thickness between approximately 0.2 and 2 microns.

The conductive substrate may comprise a layer 80 of indium tin oxide, which has been deposited by electron bombardment i on a sheet 79 of an insulating and stable material, for example, “5

Alternatively, a flexible metal sleeve could also be used on which a photoconductive coating 78 has been deposited. The coating 78 can be charged and it can retain the charge applied to it with a sufficient degree to be able to be subsequently developed by discharge. selective during the projection of a light image on the loaded coating 78. The developed image can be transferred to a carrier agent and be linked by fusion thereto.

In the present description and the claims, the ex-pressure "electrophotographic strip" is intended to designate an endless strip 62 of which at least part carries a coating or layer 78 made of a photoconductive material which can be used electrophotographically.

The strip 62 is mounted on rollers 64 and 66 so that the covering 78 is directed towards the outside when the lower strand 72 of the strip is directed downwards.

The electrophotographic strip 62 is placed in an offset position relative to the document-holding plate 36, but it is generally situated at the same level as the strands 70 and 72, at least the lower strand 72 being placed in a plane corresponding to or adjacent to the focal plane of the document-holder tray 36. One of the rollers, for example 66, is coupled to a motor 80 for the purpose of driving the strip 68. The roller 66 has a diameter slightly greater than that of the roller 64 and it acts 25 not only to drive the strip 62 but to cooperate with means placed in the development station 58 and which will be described below. The roller 66 may be hollow so as to contain the motor 80.

The loading station has been designated by 82 and it is placed in a position adjacent to the right end of the strip 62, near and below the roller 64. The loading station 82 comprises a device 84 for generating d 'corona or corona effect acting so as to apply a uniform load potential to the strip 62 when the latter passes in front of it.

The optical projection system 56 is preferably a self-contained unit which comprises a rigid carrier element 86 in the form of a molded basket, which is provided with two opposite walls * - £ "88 and 90, preferably inclined at an angle 45 ° from

S

J

6 to a bottom 92, and two connecting walls 94 and 96. The walls 94, 96 can also be inclined outwards and they include inclined edges and horizontal edges, such as those designated by the references 94 'and 94 ". Two flat mirrors 102, 104 are fixed, for example by gluing, on the interior surfaces 88 'and 90' of the walls 88 and 90.

A passage 106 is formed in the separating partition 100 and a lens system is housed in a cylindrical housing 110 while being held therein by friction. The mirror 102. 10 is placed below the document holder tray 36, while the mirror 104 is placed below the horizontal flat strand 72 of the strip 62.

There are provided in the floor of the housing part 14 and in the bottom 92 of the basket-shaped support 86 associated coupling means 15 which can be fixed in a removable manner in the housing part 14, while being correctly oriented. to project a bright image of the document to be copied located on the tray 36, with its side to be reproduced facing down, on the horizontal strand 72 of the graphic electrophoto-tape 62, after the application of a charge potential uniform on the surface of the covering 78 which is carried by the strip.

The optical projection system 65 can be defined as a "broken line" projection system due to the arrangement of the mirrors 102, 104 and the lens system 108 for which the beams 102 'and 104' define a neck 112.

The lens 108 is enclosed in a housing 110 formed of two parts 116, 118, of different diameters, which are joined together by an annular flange 120. The diameter of the opening 106 formed in the separating partition 100 is only 30 slightly greater than the diameter of the housing 118 so as to allow the friction fitting of said part 118, the flange 120 coming to rest against the partition 100.

A channel compartment 124, having opposite walls 126, 128, joins the horizontal edges 94 "arranged transversely to the support element 86 and rests on the upper edge of the separating partition 100. Suitable lamps 130 and 132 , associated with reflectors 124 and 136, are fixed relative to the end wall 88 and to the wall 126 IP "

/ L

7 of the compartment 124. The mounting console 138 is preferably produced as a part of the element 86 in the form of a one-piece molded basket. A planar reflector 139 is placed in a position adjacent to the inner left corner of the housing cover 5 and is directed correctly to reflect the light emitted by the lamp 130 in order to illuminate the document D, while the strand area tape 72 which receives the projected image can be considered as constituting the exposure station of the electrophotographic image forming system 54.

In this zone, the coating 78 carrying the uniform charge potential, which has been applied to it by the crown effect generator 84, is selectively discharged to form a latent electrostatic image of the document D.

The development station 58 includes a developer cartridge 140 which is housed in the compartment 124. The parts 12 and 16 of the casing have corresponding notched zones which are arranged to be arranged in the region of the compartment 124 when the opposite parts 14 and 16 are assembled to define an inlet for receiving the developer cartridge 140.

This developer cartridge 140 has, overall, a rectangular configuration, and it comprises an upper wall 144, provided with an elongated and curved portion 146 which has a slot 148, oriented in the longitudinal direction 25 of the cartridge 140, almost over its entire length and arranged parallel to the longitudinal edges of the part 146.

The slot 148 is placed midway between the edges of this part 146 and it is spaced internally from its end walls. The curved wall portion 146 can be made of a metal or other conductive material to act as a developing electrode. The other parts of the cartridge 140 are made of an electrically insulating material.

! The drive roller 150 can be placed in the interior volume 152 of the cartridge 140. Liquid developer 154 is introduced into the compartment 152. The roller 150 is mechanically coupled by suitable means (not visible) to the water 66 and it rotates under the impulse of the roller 66 but in * s | p the opposite direction, as indicated by the arrows 156 and 158.

Γ - N

5 8

The drive roller 150 is not in contact with the roller 66 and it does not touch the edges 146 'of the curved portion 146 which delimit the slot 148. On the contrary, the roller 150 is spaced from the roller 66 and the strip 62 driven by the latter, from a distance rising to a few tenths of a millimeter, in order to define an interval 160. Developer particles suspended in the liquid 154 are deposited on the strip 62 carrying the latent image electrostatic when this strip passes in the interval 160, this deposition being effected by a capillary effect and, also, under the impulse of the developing electrode constituted by the curved part 146 plated with metal. In correspondence, the electrostatic latent image is developed and driven at the same time as the strip 62 around the roller 66 so as to arrive in the upper strand 70 of said strip.

The carrier delivery and drive system 60 is mounted as a unitary assembly above the electrophotographic imaging system 54 and includes a compartment 162 attached to the cover 16 and provided with 20 'an access cover 164 pivotally mounted. The drive mechanism (not shown) is of the conventional type with base drive. Preferably, the carrier agent consists of payment sheets 166 which are stored in a rack 168. The rack 168 has side walls, designated by 170, a bottom wall 172, a rear wall 174 and a front wall. 176. A horizontal flange 180 is fixed on, or integral with the lower end 182 of the front wall 176 by establishing with the latter a part essentially at right angles.

A connecting part 184 is fixed on the lower surface * 30 of the bottom wall 172 and it is directed towards the outside of, and parallel to said bottom wall 172, in order to define with the rim 180 a discharge chute 186 The sheets of paper 166 from the source 60 are discharged, sheet by sheet, through the chute 186, in a transfer station 62.

This transfer station 62 comprises a transfer roller 188, electrically charged and pivotally mounted inside I of a compartment 190 placed above the rim 180.

9

The transfer roller 188 acts so as to drive each sheet of paper 166 coming from the discharge chute 186 and to facilitate the transfer of the developed image from the strip 62 when the latter and the corresponding sheet 166 pass in the interval 192 formed between the roller 188 and the roller 64. There is provided an appropriate circuit and electrical connections to create the electrical polarization * facilitating the operations of development and transfer.

The discharge bin 194 receives the sheets of paper 10 166 carrying the transferred image and coming from the interval 192.

The discharge bin 194 has a box shape open at its upper part, it has a thickened wall part 196 which is provided with a flange 198 directed downwards and an inclined upper surface 200. The inclined surface 200 provides 15 guiding the sheets of paper 166 from the interval 186 to the discharge bin 194. The flange 198 directed downwards is used to connect the compartment 194 to the casing 12 of the machine 10, ensuring a blocking on the wall extreme 20 of the latter.

As shown in the drawing, the control panel 202 is enclosed in a box 204 mounted between the document tray cover 40 and the paper supply source 60, the upper wall 206 of the control box 202 being coplanar with the access cover 164 of the paper sheet source 60. All the electronic controls and the circuit boards (not shown) are housed in this control box.

As shown in the drawing, it can be seen that the use of a large diameter roller 66, which is housed in a recessed part 146 of the developer cartridge 140, and the positioning of the smaller diameter roller 64, allow to place the strands of the strip in very close proximity to one another. The arrangement of the development station 58 between the beams 102 ′, 104, of the optical projection system 56 allows a substantial reduction in interior volume to be achieved. The arrangement of the developer cartridge compartment 124 inside the neck 112 and just above the lens system 108, and the use of the optical projection system 56 in "broken line", also makes it possible to use the maximum 10 the available space and consequently reduce the overall vertical dimension of the machine 10, that is to say to give it a low profile. The results described above are obtained without miniaturization of the components and, also, without reduction of the capacity for use, without loss of flexibility or resolution compared to conventional larger and more bulky machines.

Of course, the invention is not limited to the embodiments described above, which can be the subject of many variants.

m

Claims (3)

1.- electrophotographic copying machine with low profile, particularly suitable for use as a table top panel and comprising: a support plate for the document 5 to be copied, an electrophotographic strip, a charging station, an exposure station and a development station; a source of carrier agent supply and a corresponding training station 1; an optical projection station directing a light image of the document onto the electrophotographic strip, and a transfer station for applying the developed image to said carrier agent, as well as a support and drive mechanism for ensuring the drive of the electrophotographic strip consecutively in front of said stations, machine characterized in that the strip is arranged to define two strands .15 oriented horizontally and placed in close proximity to each other, in that the exposure station is positioned on the lower strand j between the ends of said strip, in that | the optical projection station comprises a broken line system provided with two spaced beams, said development station being housed between the spaced beams and inside said optical projection station, in that the document holder tray is oriented towards said optical projection system so that the lower strand of said electrophotographic strip is spaced from said plate and is placed essen- | 25 tally at the same level, and in that the drive mechanism comprises a driving roller which is housed in said development station in order to guide the strip, said source of carrier agent and said drive station being placed: immediately above the electrophotographi-30 exposure station, approximately at the same level as the document tray. j - 2.- copying machine according to claim l, characterized in that the drive mechanism also comprises a follower roller with a diameter smaller than that of the driving roller. 3.- Copying machine according to claim 1 or 2, charac-35 terized in that it comprises a housing comprising an upper wall, a lower wall and two side walls defi i! . connecting two opposite corner upper parts, the station of: 1 supply of carrier agent being placed in an upper corner, 12 said optical projection system comprising a carrier element in the form of a rigid basket which is provided with two inclined walls placed one opposite the other, two mirrors fixed on said inclined walls, each mirror being placed on the wall surface which is directed inwards, in that said basket-shaped carrying element comprises a vertical dividing wall provided of an opening in which is housed a lens system which is aligned with said mirrors to project an image from the document holder onto said electrophotographic strip, in that said development station is placed on said dividing wall at the inside of the upper part of said basket-shaped carrier element, in that said electrophotographic strip is placed between said development station and said carrier agent supply station, in that said development station comprises a "developer cartridge placed in close proximity to one end of said electrophotographic tape, and in that said charge station is placed in a position adjacent to the opposite end of said electrophotographic strip. 4. A copying machine according to claim 3, characterized in that it comprises a compartment-forming structure which comes to press on said separating partition and which can receive said cartridge in order to place it near the electrophotographic strip of so as to fulfill a function of developing said strip, in that said cartridge comprises an upper wall and an elongated longitudinal slot formed along its length, and in that it is provided inside. from the cartridge, a roller applicator for depositing liquid developer on said strip. 5. A copying machine according to claim 4, characterized in that the drive roller is placed near the developer cartridge and has a larger diameter than that of the other roller provided at the opposite end of the strip, the outer periphery of the drive roller being placed in close proximity to said elongated slot of said developer cartridge. D 13 6. Copying machine according to claim 4 or 5, characterized in that an electric polarization generator is provided to create an electric polarization between the developer cartridge * and the electrophotographic strip during the development phase. 7, - Copying machine according to any one of claims 1 to 6, characterized in that the transfer station comprises a transfer roller placed near said upper strand of the strip in order to define with it an interval, 10 and in a second electric polarization generator is provided to create an electric polarization in said interval during the passage of said carrier agent therein. AT "