MXPA97000591A - Air exhaust seal through camera derecirculac - Google Patents

Abstract

The present invention relates to a channel for recirculating a stream of air, located adjacent to a stream of particles of image formation that exits substantially in an angular manner from an element of transport of particles of imaging, the stream of particles of image formation defines an internal boundary thereof that extends tangentially from a first position adjacent to the transport element and that defines an external boundary of the transport element and the internal boundary thereof, the channel is characterized in that it comprises: a first element, the first element is positioned outside the stream of image formation particles, at least a portion of the first element is positioned substantially adjacent to the external boundary of the stream of image formation and spaced particles of the transport element a second element joined to the first element, and a third element attached to the second element, the second element is positioned adjacent to the transport element and spacing of the stream of image forming particles, substantially all of the air stream that is directed by the first element is sequentially directed by the second element and the third element

Description

AIR EXHAUST SEAL THROUGH RECIRCULATION CHAMBER Description of the invention The present invention relates to a developer and / or cleaning apparatus for electrophotographic printing. More specifically, the invention relates to the provision of a conduit for recirculating air within a developing and / or cleaning unit. In the well-known electrophotographic printing process, a charge retaining surface, commonly known as a photoreceptor, is electrostatically charged and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and unloaded areas on the receiver forms an electrostatic charge pattern known as a latent image according to the original image. The latent image is revealed by exposing it to a powder that can be electrostatically attracted, finely divided, known as "organic pigment". The organic pigment is retained on the image areas by electrostatic charging on the photoreceptor surface. Thus, an organic pigment image is produced in accordance with a light image of the original that is reproduced. Then the organic pigment image can be transferred to a substrate or support element (eg, paper) and the image fixed thereto to form a permanent record of the image to be reproduced. Subsequent to development, the excess organic pigment left on the surface that retains charge is cleaned from the surface. The process is useful for copying with light lens an original or print of stored originals or REF: 23644 generated electronically, such as a frame output scanner (ROS, raster output scanner) where a surface Loaded can be downloaded to imaging mode in a variety of ways. In the electrophotographic printing process, the step of transporting organic pigment to the latent image on the photoreceptor is known as "developing": The object of the effective development of a latent image on the photoreceptor is to transport the developing material to the latent image to a speed controlled in such a way that the developer material normally in the form of an organic pigment electrostatically adheres effectively to the printed areas on the surface retaining the charge. Referring now to Figures 2 and 3, a disclosing unit 1 of the prior art is shown. The developer unit 1 normally includes a developer housing 3 which defines a chamber 5 for housing the developer within the developing housing 3. The developer material 7 is axially moved within the chamber 5. An image transport element 9 commonly carries the developer material 8 from the chamber 8 to the oil spout roll 8. The oil spout roller is a roller that extracts the organic pigment from the developer material and is always coated with a thin layer of organic pigment only. Commonly, the element 9 for transporting image-forming particles is in the form of a roller.

The photoreceptor on which the image is formed must be moved at a high speed adjacent to the oil spout roller. To ensure that the entire latent image is revealed, the oil spout roller carries sufficient organic pigment to fill all portions of the latent image and normally includes an amount of organic pigment in excess of that required to reveal the latent image. The developer material includes carrier particles and organic pigment. The developer material on the image transporting element 9 loses most of its organic pigment as it comes into contact with the oil spout roller. Then the material is released from the transport roller into the chamber 5 of the developing unit 1 towards the rear wall 11 of the housing of the developer 3 (see FIG. 2). With reference now to figure 3The imaging particles released, together with entrained air, bounce off the upper wall 11 of the developer housing 3 and move outward to the outer edges 13 and 15 of the developer housing. Then the image and air-forming particles escape from the developer housing to cause contamination to appear within the interior of the copier or photocopier. This flow of air and particles of imaging creates a pressure inside the chamber 5 greater than the ambient pressure, which makes the sealing of the outer edges 13 and 15 of the housing 3 of the developer extremely difficult. Air and organic pigment discharged from the developer unit can contaminate the rest of the copier.

The containment of the developer material with a developing unit using hybrid development without a cleaner is particularly a concern. The purpose and function of the development without cleaner is more fully described in, for example, U.S. Patent 4,868,600 issued to Hays et al., U.S. Patent 4,984,019 issued to Folkins, U.S. Patent 5,010,367 issued to Hays, and U.S. Patent 5,063,875 issued to Hays et al. Folkins et ai. U.S. Patent 4,868,600 is incorporated herein by reference. In a developer system without a cleaner, the organic pigment is separated from the oil jet roller by applying an AC (alternating current) electric field to the self-spaced electrode structures, commonly in the form of wires positioned in the space between rollers between an oil spout and photoreceptor roll in the case of hybrid development without a cleaner or by applying the AC electric field directly to the oil spout roll in the case of hybrid hop development. This forms a cloud of organic pigment dust in the space between rollers and the latent image attracts the organic pigment from the dust cloud to it. Because there is no physical contact between the developing apparatus and the photoreceptor, developing without a cleaner is useful for devices in which different types of organic pigment are supplied on the same photoreceptor, such as in "tri-level" xerography "," recharge, exposure and development "," outstanding "; or color xerography of "image on image". Since hybrid development without a cleaner depends on a continuous cloud of organic pigment powder in the space between rollers between the latent image and the oil spout, the speeds at which the rollers work are significantly higher and therefore the The emission potential is also much higher. In addition to problems with the emission of organic pigment from a developing housing in high-volume printing and copiers, similar problems arise with the emissions of organic pigment in the cleaning of the housings. Referring now to Figures 4 and 5, a cleaning unit 1a of the prior art is shown. The cleaning unit 1a is used to remove the organic pigment 7a and the contaminants from the photoreceptor 8a. The cleaning unit 1a commonly includes a cleaning housing 3a which defines a chamber 5a of the cleaning housing within the cleaning housing 3a. The separated organic pigment 7a is collected within the chamber 5a. A brush 9a normally contacts the photoreceptor 8a and loosens the remaining organic pigment 7a and the photoreceptor contaminants 8a. Then a cleaning sheet 2a scrapes the organic pigment 7a. The wasted organic pigment 7a and the photoreceptor contaminants 8a are advanced by the sheet 2a, the brush 9a and the gravity to a bottle 4a for the organic pigment used within the chamber 5a of the housing 3a. The photoreceptor on which the image is formed must be moved at a high speed. To ensure that the photoreceptor is properly cleaned, the brush 9a must rotate at a sufficient speed to loosen the organic pigment 7a and the photoreceptor contaminants. Then a portion of the organic pigment 7a and the contaminants on the photoreceptor are shaken from the brush 9a to the chamber 5 of the cleaning unit 1 (see figure 4). Referring now to Figure 5, the separated organic pigment 7a together with entrained air within the cleaning housing 3a move outward to the outer edges 13a and 15a of the cleaning housing 3a. Then the organic pigment 7a and the air escape from the cleaning housing 3a to cause contamination to appear inside the copier. This flow of air and organic pigment creates a pressure inside the chamber 5a greater than the environmental pressure that makes the sealing on the outer edges 13a and 15a of the cleaning housing 3a extremely difficult. Exhausted organic air and pigment leaving the cleaning unit can contaminate the rest of the copier. The following descriptions may be relevant to various aspects of the present invention: U.S. Patent 4, 168, 901 Assignee: Ito et al. Date of issue: September 25, 1979 US Patent 4,361, 396 Assignee: Uchida Issue Date: November 30, 1982 U.S. Patent 4,583,112 Assignee: Morano et al. Date of issue: April 15, 1986 US Patent 4,800.41 1 5 Assignee. Tanaka et al. Date of issue: January 24, 1989 US Patent 4,809,035 Assignee: Alien, Jr. ío Date of issue: February 28, 1989 US Patent 4,963,930 Assignee: Yoshimaru Date of issue: October 16, 1990 United States Patent 5,047,807 Assignee: Kalyandurg Date of issue: September 10, 1991 US Patent 5,243,388 Assignee: Berns et al. Issue date: September 7, 1993 Relevant portions of the foregoing descriptions can be briefly summarized as follows: U.S. Patent 4,168,901 discloses a relay device to prevent dispersion of the developer in an electrophotographic copying machine. The device is applicable to a developing device or a cleaning device in opposite relation to the surface of a photosensitive drum. The device includes an element that prevents the dispersion of the developer in the form of a multi-flange support which closely conforms to the photosensitive drum. U.S. Patent 4,361,396 describes an apparatus for collecting dispersed magnetic organic pigment. The apparatus includes an air flow path, an organic pigment collection chamber at one end of the flow path, a suction device for generating an air flow to the collection chamber and magnets in the collection chamber. U.S. Patent 4,583,112 discloses a vent for venting the interior of a developer housing. A hopper of organic pigment is located on top of the developer housing. An exhaust port is located in the upper portion of the developer housing between the housing and the hopper. A filter is located in the gate. A wall is located between the chamber of the housing and the gate and the exhaust bifurcates between the wall and the aniojamiento. U.S. Patent 4,800,411 discloses a magnetic brush developer that includes a cleaning sheet to control the amount of developer on the magnetic roller. A sheet that limits the fibers of the organic pigment is located spaced from the roll, downstream of the cleaning sheet. A passage for the air flow is located in the limiting sheet and allows the flow of air from downstream of the limiting sheet upstream of the limiting sheet, to equalize the pressures between them. U.S. Patent 4,809,035 discloses a single component developing apparatus that includes a chamber for unwanted non-magnetic particles, which extends along the width of the unit for the organic pigment below the outlet of the organic pigment hopper . The non-magnetic particles pass through the magnetic roller not attracted thereto and are extracted by means of an impelling apparatus to the chamber for the non-magnetic non-desired particles. U.S. Patent 4,963,930 discloses a developing apparatus that uses dry organic pigment. The apparatus includes a developer housing that has a vent therein with a filter that covers the vent. The housing is under positive pressure with the developer housing spaced closely from the photoconductive drum, so that the incoming air is at high speed to prevent developer leakage. U.S. Patent 5,047,807 discloses an internal cleaning device, which includes a single, non-magnetic, electrically conductive, rigid plate, which has an opening therein for the photoconductive drum. The plate is electrically charged to attract the organic pigment.

U.S. Patent 5,243,388 discloses an apparatus for cleaning a developing unit that includes a cover placed on the developing unit. The cover has an entrance for air and an exit for air. A vacuum source is connected to the air gap, to create an air flow inside the developer unit for cleaning. According to the present invention there is provided a channel for recirculating an air stream, located adjacent to a stream of imaging particles that exit substantially tangentially from a transport element of the imaging particles. The stream of image forming particles defines an internal boundary thereof, which extends tangentially from a first position adjacent to the transport element and defines an outer boundary thereof spaced from the transport element and the internal boundary. The channel defines a first element positioned outside the stream of image formation particles. At least a portion of the first element is positioned substantially adjacent to the external boundary of the stream of image formation particles and is spaced apart from the transport element. The channel also includes a second element attached to the first element and a third element joined to the second element. The second element is positioned adjacent to the transport element and is spaced from the stream of image formation particles. Substantially all air stream that is directed by the first element is directed sequentially by the second element and the third element.

According to the present invention, a developing unit for the development with imaging particles of a latent image recorded on an element that receives the image to form a developed image is also provided. The developing unit includes a housing for containing a supply of at least image forming particles and a transport element mounted in the housing for transporting the image forming particles to the image receiving element. The developing unit also includes a channel for recirculating a stream of air, located adjacent to a stream of imaging particles that exits substantially tangentially from a transport element for the imaging particles. The stream of image forming particles defines an internal boundary thereof that extends tangentially from a first position adjacent to the transport element and defines an outer boundary thereof spaced from the transport element and the internal boundary. The channel includes a first element positioned outside the stream of image forming particles. At least a portion of the first element is positioned substantially adjacent to the outer boundary of the stream of image formation and spaced particles of the transport element. The channel includes a second element joined to the first element and a third element joined to the second element. The second element is positioned adjacent to the transport element and spacing of the stream of image forming particles. Substantially all of the air stream directed by the first element is sequentially directed by the second element and the third element. An electrophotographic printing machine of the type having a developing unit adapted for the development with imaging particles of an electrostatic latent image recorded on a photoconductive element is also provided. The developing unit includes a housing for containing a supply of at least image forming particles and a transport element mounted in the housing for transporting the image forming particles to the image receiving element. The developing unit also includes a channel for recirculating a stream of air, located adjacent to a stream of imaging particles that exit substantially tangentially from a transport element for the imaging particles. The stream of image forming particles defines an internal boundary thereof which extends tangentially from a first position adjacent to the transport element and which defines an outer boundary thereof spaced apart from the transport element and the internal boundary. The channel includes a first element positioned outside the stream of image forming particles. At least a portion of the first element is positioned substantially adjacent the outer boundary of the stream of image formation particles and spaced apart from the transport element. The channel includes a second element joined to the first element and a third element joined to the second element. The second element is positioned adjacent to the transport element and spacing of the stream of image forming particles. Substantially all of the air stream directed by the first element is sequentially directed by the second element and the third element. A cleaning unit is also provided to clean the image formation particles in excess of an element that receives the image. The unit includes a housing for containing a supply of at least excess image formation particles and a cleaning element mounted in the housing for cleaning the image formation particles of the image receiving element. The unit also includes a channel to recirculate an air current, located adjacent to a stream of particles of image formation that comes out substantially tangentially from the cleaning element. The stream of image forming particles defines an internal boundary thereof that extends tangentially from a first position adjacent to the transport element and defines an outer boundary thereof spaced from the transport element and the internal boundary. The channel includes a first element positioned outside the stream of image forming particles. At least a portion of the first element is positioned substantially adjacent to the outer boundary of the stream of image formation and spaced particles of the transport element. The channel also includes a second element attached to the first element and a third element joined to the second element. The second element is positioned adjacent to the transport element and spacing of the stream of image forming particles. Substantially all the air stream that is directed by the first element is sequentially directed by the second element and the third element.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial sectional view of a developing housing that includes a conduit for recirculating air and developer material within the developing housing according to the present invention, through section 1-1 of the developer unit of the copier of Figure 6; Figure 1A is a partial sectional view of a portion of the developing housing of Figure 1; Figure 2 is a partial sectional view of a development housing of the prior art; Figure 3 is a top view of the developing housing of the prior art of Figure 2; Figure 4 is a partial sectional view of a cleaning attachment of the prior art; Figure 5 is a top view of the cleaning housing of the prior art of Figure 4; Figure 6 is a schematic view of an illustrative electrophotographic printing machine incorporating the recirculation duct of the developing apparatus of the present invention therein; Figure 7 is a top view of the recirculation duct of Figure 1; Figure 8 is a graph of the velocity of the magnetic roll against the pressure above the ambient for the housing of the prior art and the recirculation duct of the developing apparatus of the present invention; Figure 9 is a graph of the total powder measured at a concentration of 3% organic pigment at various sites outside of the developing housing for housing of the prior art and the developer housing including the recirculation conduit of the present invention; Y Figure 10 is a graph of the total powder measured at a 5% organic pigment concentration at various sites outside of the developer housing for the prior art housing and the developer housing including the recirculation duct of the present invention . Figure 11 is a partial sectional view of an alternative embodiment of a developing housing that includes a conduit for recirculating air and developer material within the developing housing according to the present invention; Fig. 11A is a partial sectional view of a portion of the developing housing of Fig. 11; Fig. 12 is a partial sectional view of a cleaning housing including a conduit for recirculating air and developer material into the cleaning housing; according to the present invention through section 2-2 of the developing unit of the copier of figure 6; Figure 13 is a table of location against the pressure above the environment for housing the prior art and the recirculation duct of the cleaning apparatus of the present invention. While the present invention will be described in relation to a preferred embodiment thereof, it will be understood that it is not proposed to limit the invention to that embodiment. On the contrary, attempts are made to cover all alternatives, modifications and equivalents as may be included in the spirit and scope of the invention as defined by the appended claims. Since the electrophotographic printing technique is well known, the various processing stations employed in Figure 6, the printing machine will be shown schematically in the present and its operation briefly described with respect thereto. Referring now to Figure 6, there is shown an electrophotographic printing machine incorporating the developing apparatus of the present invention therein. The printing machine incorporates a photoreceptor 10 in the form of a band having a photoconductive surface layer 12 on an electroconductive substrate 14. Preferably, the surface 12 is made of a setenium alloy. The substrate 14 is preferably manufactured from an aluminum alloy which is electrically grounded. The band is driven by the motor 24 along a path defined by the rollers 18, 20 and 22, the direction of movement is counterclockwise as seen and as shown by arrow 16. Initially, a portion of band 10 passes through a charging station A in which a generator of corona 26 charges the surface 12 to a relatively high, substantially uniform potential. A high voltage power supply 28 is coupled to the generator 26. Next, the charged portion of the photoconductive surface 12 is advanced through the exposure station B. In the exposure station B, an original document 36 is positioned on a frame input scanner (RIS), generally indicated by reference number 29. The RIS contains lamps for illuminating the document, optical components, a mechanical scanning actuator and a load coupling device (CCD array) ). The RIS captures the entire original document and converts it to a series of raster scan lines and (for color printing) measures a set of primary color densities, that is, densities of green and blue at each point of the original document. This information is transmitted to an image processing system (IPS), indicated generally by the reference number 30. The IPS 30 comprises the electronic control components which prepare and manage the flow of image data to the output scanner. frame (ROS), indicated generally by the reference number 34. An interface for the user (Ul), indicated in general by the reference number 32, is in communication with the IPS. The Ul allows the operator to control the various functions adjustable by the operator. The signal output from the Ul is transmitted to the IPS 30. The signal corresponding to the desired image is transmitted from the IPS 30 to the ROS 34 which creates the output copy image. The ROS 34 arranges the image in a series of horizontal scan lines, each line having a specific number of pixels per centimeter (or inch). The ROS includes a laser that has a block of rotating polygonal mirrors associated therewith. The ROS exposes the charged photoconductor surface of the printer. After the electrostatic latent image has been recorded on the photoconductive surface 12, the web 10 advances the latent image to the developing station C as shown in Fig. 6. In the developing station C, a developing system 38, reveals the latent image recorded on the photoconductive surface. The chamber in the developing housing 44 stores a supply of developer material 47. The developer material can be a two-component developer material of at least magnetic carrier granules having triboeiéctricaly adhered organic pigment particles. the same. It should be appreciated that the developer material may also comprise a component developer material consisting primarily of organic pigment particles. Again with reference to Figure 6, after the electrostatic latent image has been revealed, the web 10 advances the developed image to the transfer station D, in which a copy sheet 54 is advanced by the roller 54 and the guides 56 in contact with the revealed image on the band 10. A corona generator 58 is used to spray ions on the back of the sheet, to attract the organic pigment image from the band 10 to the sheet. As the band rotates around the roller 81, the sheet is separated therefrom with the image of organic pigment thereon.

After the transfer, the sheet is advanced by a conveyor (not shown) to the melting station E. The melting station E includes a heated melting roll 64 and a reinforcing roll 66. The sheet passes between the roll Fusion 64 and the reinforcement roller 66 with the image of organic pigment powder in contact with the melting roller 64. In this way, the image of organic pigment powder is permanently fixed to the sheet. After melting, the sheet advances through the ramp 70 to the receiving tray 72 for subsequent separation from the printing machine by the operator. After the sheet is separated from the photoconductive surface 12 of the strip 10, the residual developer material adhering to the photoconductive surface 12 is separated therefrom in the cleaning station F by a fibrous brush 74 rotatably mounted, in contact with the photoconductive surface 12. Subsequent to cleaning, a discharge lamp (not shown) floods the photoconductive surface 12 with light to dissipate any residual electrostatic charge remaining thereon, prior to charging it for the next successive printing cycle . It is believed that the above description is sufficient for the purposes of the present application to illustrate the general operation of an electrophotographic printing machine incorporating the developing apparatus of the present invention therein. The developing system 38 of the present invention as shown in Figure 6 is shown in greater detail in Figure 1. The developing system includes the developing unit 78. The developing unit 78 includes the developer housing 44 which defines a camera 80 in the same. The developer material 47 is located within the chamber 80 of the developer housing 44. The developer material 47 may consist essentially of image forming particles 82, preferably in the form of organic pigment particles. Preferably, however, the revealing material 47 includes in addition to the organic pigment particles 82, carrier granules 84 to which the organic pigment particles 82 are triboethetrically attracted. The use of the carrier granules 84 improves mixing and loading of the organic pigment particles 82. The developing material 47 is advanced towards the latent image 86 on the photoconductive surface 12 of the photoconductive strip 10 by the transport element 90 of the particles of image formation. The transport member 90 of the image forming particles can take any suitable shape such as a band or a worm, but is preferably in the form of a roller. When the developing material 47 includes carrier granules 84 as well as the organic pigment particles 82, the transport element 90 is preferably in the form of a magnetic roller. The magnetic roller 90 may have any suitable configuration, but preferably includes a stationary core 92 that includes a permanent magnet opposite the reservoir of the developer housing 44. The stationary core 92 is surrounded by a rotating sleeve 96. The sleeve 96 is made of a non-magnetic material, for example aluminum. The permanent magnet 94 attracts the carrier granules 84 which form the carrier granule chain 84 with organic pigment particles 82 attracted to the surface of the sleeve 96. The rotating sleeve 96 advances the particles 82. These chains of the developer material 47 include carrier granules 84 attracted thereto, also as organic pigment particles 82 triboelectrically attracted to the carrier granules 84 form strings of developer material 47 on a periphery 98 of the sleeve 96 of the magnetic roller 90. When using magnetic brush development (not shown) ) the chains of the developer material are rubbed against the latent image with the organic pigment particles attracted to the latent image. It should be appreciated that, as shown in Figure 1, a developer housing 44 containing two component developer material 47, including carrier granules 84 and organic pigment particles 82, can be used with the development of a single component. In such a system, an oil spout 100 is used to remove the organic pigment particles 82 from the granules 84 of the carrier. Then the organic pigment particles 82 are transferred to the latent image 86 by the oil spout roll 100. It should be appreciated that the oil spout 100 may also be in another form, for example an oil supply band. The oil spout 100 is positioned between the magnetic roller 90 and the photoconductive element 10. The chains of the developer material 48 are rubbed against the oil spout roller. The oil spout 100 is electrically charged with a charge of opposite polarity to that of the organic pigment particles. By this the organic pigment particles 82 are attracted to the periphery 102 of the oil spout roll 00. As the oil spout 100 rotates, the organic pigment particles 82 are advanced to the latent image 86. When the Hybrid Jump Development (HJD) is used the photoconductive band is electrically biased with respect to the spout roll 100 oil, in such a way that the organic pigment particles are electrically attracted from the oil spout and jump to the latent image, thereby revealing it. When electrodes (not shown) of hybrid development without a cleaner (HSD) are used with the electrodes located either on the periphery of the oil spout or in the space between the oil spout and the photoconductor strip, they are electrically charged to cause that the organic pigment particles are attracted to the position between the oil spout roller and the photoconductive strip. The oil spout 100 can be manufactured from a core 103 of a suitable durable, electrically conductive material, such as plastic, which includes an electrically conductive material dispersed therein or can be fabricated from an electrically conductive metal. A semiconductor layer 104 is applied over the core to provide an appropriate resistive capacitor circuit through the semiconductor layer 04. In order for the magnetic roller 90 to provide sufficient organic pigment particles 82 to the oil spout 100, where the copier produces a high volume of copies, for example 60 copies per minute or more, the magnetic roller 90 must rotate at high speed. For example, for a copier that produces more than 60 cpm, a magnetic roller 90 with a diameter of 2.5 cm (1 inch) needs to travel in excess of 764 rpm or 102 cm (40 inches) per second added to the periphery 98 of the roller magnetic 90. When the magnetic roller 90 rotates in the direction of the arrow 105, the organic pigment particles 82 in excess, which are not transferred to the oil spout roll 100, are driven tangentially from a first position 106 on the periphery 98. of the magnetic roller 90. The first positions 106 represent a position on the magnetic roller 90 which is slightly away from the permanent magnet 94. This position is where the centrifugal force on the organic pigment by the rapidly rotating magnetic roller 90 exceeds the magnetic force of the magnet 94. The stream of organic pigment particles 82 exiting tangentially from the first position 106 of the magnetic roller ico 90 forms an internal stream 108 of image forming particles. The internal stream 108 diverges as it separates from the magnetic roller 90. The particles within the divergent internal stream 108 have a distribution that is centered around the center line 109. The particular shape of the distribution varies with the shape of the housing of the developer and the speed of the transport roller 90. The shape of the distribution can be normal with most of the particles located near the center line 109. Most of the particles are located between an internal boundary 110 and an external boundary 112.

The internal stream 108 is internally limited by the internal boundary 110. The internal stream 108 is further defined by the outer boundary 112 spaced from the inner boundary 110 and extending tangentily from a slightly spaced position of the periphery 98 of the magnetic roll 90. The internal stream 108 extends outwardly between the internal boundaries 110 and the outer boundaries 112 and is further limited by the wall 114 between the outer border 112 and the inner border 110. The internal stream 108 of image forming particles which collide on the wall 114 fall by gravity to the reservoir of the housing 44 of the developer. Positioned slightly externally to the outer border 112 of the image forming particles is an external stream 116 that includes air with image forming particles 82 entrained within the external stream 116. The wall 114 separates the first auger 120 from the second endless 122. The imaging particles 82 of the internal stream 108 of the image forming particles fall into the reservoir of the developer housing 44. The particles 82 are first extracted by the first auger 120 to an end of the auger 120 in which a passage or passage allows the organic pigment particles 82 to pass through the wall 114 to the second auger 122. The second auger 122 moves the particles 82 of organic pigment in the direction opposite to a second opening at the opposite end of the developer housing. The circulating path of the organic pigment particles through the first auger 120 and the second auger 122 promotes the mixing of the organic pigment particles 82 with the carrier granules 84 and promotes the loading of the organic pigment particles 82. Referring now to FIG. 1A, the external air and particle stream 116 is directed from a downstream position of the magnetic roller 90 to an upstream position of the magnetic roller 90 via a channel 130. The channel 130 may have any suitable shape for appropriately directing the current 116. For example the channel may include a wall 132 for directing the current 116. Preferably the wall is arcuate, for example concave, to promote the movement of air in a circular configuration in the direction of the arrow 134. It has been found that the air flow in the channel is very dependent on the shape of the wall. The optimal form can be determined experimentally or can be modeled by sufficient experimental data of roller speeds and forms of the developer. The wall 132 can be divided into three areas or elements. These areas of preference include a first element 136 or portion of the wall 132 for receiving the external air stream 116 and the expelled stream of material exiting the magnetic roller 90, a second element 140 or portion of the wall 132 for transferring the air received from the first element 136, also as a third element 142 or portion of the wall 132 for transferring the received air from the second element 140 and for expelling the external air stream 116 to a position adjacent the magnetic roller 90 upstream of the first position 106 of the magnetic roller 90.

The channel 130 is made of any suitable durable material, for example metal or plastic sheeting and can be integrally molded with the developer housing 44 or secured to the developer housing in any suitable method such as welding, fasteners or by adhesives. The first element 136, second element 140 and third element 144 have a thickness T1 which is sufficient for the strength of the channel 130 and can be of a thickness similar to that of the housing 44. To promote uniform air flow, the first element 136 it is preferably combined with the second element 140 at a first transition point 144. Similarly,, the second element 140 is preferably combined uniformly with the third element 142 at a first transition point 146. The channel 130 preferably includes a protrusion or protrusion 150 which extends towards the roller 90 and serves to separate the external current 116. of the internal component 108. The projection 150 includes an inflection point 152 which represents a first end of the first element 136. The external current 116 makes an impact with the first element 136 at an included angle a. Preferably the angle α is sharp to direct the air stream in the direction of the arrow 134. The first element 136 is preferably arcuate, preferably concave. The first element 136 can be described by the radius Ri. The second element 140 is preferably arcuate, preferably concave. The second element 140 can be described by the radius R2. The third element 142 is preferably arched, preferably concave. The third element 142 can be described by the radius R3. The third element may further include a portion 153 that extends generally radially toward the roller 90 to direct the stream to attach the developer material to the roller 90. The developer housing 44 preferably includes a guide portion 154 of the organic pigment, which extends downwardly from the inflection point 152. The guide portion 154 serves to direct the internal stream 108 toward the wall 114. The guide portion 154 of the organic pigment is preferably arcuate, preferably concave. The guide portion 154 of the organic pigment can be described by the radius R. The air stream 116 that comes into contact with the wall 132 in the first element 136 is directed by the first element 136 to the second element 140, then directed by the second element 140 to the third element 142 where it leaves the channel 130. Referring now to Figure 7, the channel preferably extends from the first end 160 of the magnetic roller 90 to the second end 162 of the magnetic roller 90. The external air stream 116 is directed via the channel 130 to form a series of trajectories of recirculation 164 within channel 130. Recirculation paths 164 extremely prevent new air from entering developing system 38 in opening 168.

Since little new air is introduced into the housing 44, the pressure within the developer housing 44 can be stabilized and normalized to a pressure substantially similar to ambient pressure. By using air driven by the moving parts within the housing 44, such as the transport roller 90 and by the released material and by recirculating the air within the channel 130, the need to drive more air into the housing 44 is minimized. Figure 8 is a representation of the experimental data taken from the pressure inside the developer housing 44 of a developing unit including the channel of the present invention, as well as the pressure corresponding to the interior of a developer housing that does not have the recirculation channel. These pressures are plotted to a peripheral surface footage (or number of feet) of the magnetic roller from 76 to 127 m (30 to 50 ft) per second. Line 170 shows the pressure against the speed of the magnetic roller for a housing of the developer including the channel of the present invention, while line 172 shows the pressure inside the housing of the developer against the speed of the magnetic roller for a housing of development of the prior art. Since the pressure inside the housing 44 of the developer of a developing system including a channel according to the present invention is much lower than a housing of the prior art developer, the tendency of the organic pigment particles 82 to leakage from the developer housing 44 is extremely reduced.

An experiment has been carried out with a housing of the developer including the channel of the present invention and a housing of the developer that does not include the channel of the present invention and the measured total amount of the organic pigment expelled from the developer housing has been plotted. in various positions on the periphery of the developer housing. These positions include: a position anterior to the exterior of the transport roller (pre-roller), a position later to the interior of the transport roller (post-roller) and three positions along the width of the developer housing. These three positions adjacent to the magnetic roller include: exterior, interior and center. These measurements were taken at a 3 percent organic pigment concentration, also as a 5 percent organic pigment concentration. These data are shown in Figure 9 and Figure 10. An alternative embodiment of a developer system including the channel of the present invention is shown in the developer system 380 which includes the channel 330 as shown in Figures 11 and 11 A The developer system 380 of Figures 11 and 11A is similar to the developer system 38 of Figures 1 and 1A. The developer system 380 includes the housing 344 of the developer et which defines a chamber 380 therein. The housing 344 is similar to the housing 44 of FIG. 1. The developing system 380 includes the magnetic roller 390 which is similar to the roller 90 of FIG. 1. The developing system 380 further includes the oil spout 395, the which is similar to roll 100 of figure 1.

As with the roller 90, the roller 390 provides sufficient organic pigment particles 82 to the oil spout roll 395, where the copier produces a high volume of copies, for example 60 copies per minute or more, and the magnetic roller 390 must rotate to high speed. For example, for a copier that produces in excess of 60 cpm, a magnetic roller 390 with a diameter of 2.5 cm (1 inch) needs to travel in excess of 764 rpm or 102 cm (40 inches) per second at the periphery 398 of the roller magnetic 390. When the magnetic roller 390 rotates in the direction of the arrow 305, the particles 82 of excess organic pigment, which are not transferred to the roller 395 oil spout, they are urged tangentially from a first position 306 on the periphery 398 of the magnetic roller 390. The stream of organic pigment particles 82 that exit tangentially from the first position 306 of the magnetic roller 390 form an internal stream 308 of image forming particles. The internal stream 308 is internally limited by an internal boundary 310. The internal stream 308 is further defined by an outer boundary 312 spaced from the inner boundary 310 and extends tangentially from a slightly spaced position of the periphery 398 of the magnetic roll 390. internal stream 308 extends outwardly between inner boundaries 310 and outer boundaries 312 and is further limited by wall 314 between outer boundary 312 and inner boundary 310. Internal stream 308 of image forming particles which collide on the wall 314 fall by gravity to the reservoir of the housing 344 of the developer 344.

Positioned slightly externally to the outer border 312 of the image forming particles is an external stream 316 that includes air with image forming particles 82 entrained within the external stream 316. The wall 314 separates the first auger 320 from the second auger 322.

The image forming particles 82 of the internal stream 308 of image forming particles fall to the reservoir of the developer housing 344. The particles 82 are removed by the first auger 320 to an end of the auger 320 in which a passage or passage it allows the organic pigment particles 82 to pass through the wall 314 to the second auger 322. The second auger 322 translates the organic pigment particles 82 in the opposite direction to a second opening at the opposite end of the developing housing. The path of circulation of the organic pigment particles through the first auger 320 and the second auger 322 promotes the mixing of the organic pigment particles 82 with the carrier granules 84 and promotes the loading of the organic pigment particles 82. The external stream 316 of air and organic pigment particles is directed from a downstream position of the magnetic roller 90 to an upstream position of the magnetic roller 90 via a channel 330. The channel 330 may have any suitable shape and preferably includes an inlet 332 to receive the external stream 316 from the air exiting the magnetic roller 90, also as an outlet 334 to expel the external air stream 316 to a position adjacent the magnetic roller 90 upstream of the first position 306 of the magnetic roller 90. channel 330 includes an internal boundary element 333 which serves to work with outer wall 335 to allow channel 330 to form a conduit. Depending on the orientation of the conduit 330, the organic pigment may accumulate on the internal boundary element 333 to cause the conduit to be clogged. However, the conduit 330 directs more positively the external current 316 that the channel 130 can direct the current 116. The conduit 330 is made of any suitable, durable material, for example metal or plastic sheeting and can be molded integrally with the housing of the developer 344 or securing to the developing housing by any suitable method, such as welding, fasteners or by adhesives. Referring now to Fig. 11A, preferably, to promote the flow of the external air stream 316 through the conduit 330, the inlet 332 has an entry centerline 334, which forms an angle a between the central line of input 334 and external current 316 of air. The angle a is preferably much smaller than 90 degrees to promote the flow of the external air stream 316. Also, the outlet 334 has an outlet centerline 340 which forms an angle β between the outlet center line 340 and the line 337 through the roller 390 and the position 306. The angle β is preferably less than 90 degrees. . The angles a and ß of approximately 45 degrees have been found effective. To provide angles a and ß of about 45 degrees, preferably conduit 330 includes a first member 342, a third member 345 and a second member 346 located therebetween. The first element 342 is defined by an outer radius Ro. The first element 342 has a width of Ta. The inlet 332 has a central position P, which is positioned somewhat close to the wall 314 and preferably slightly outside the outer border 312 of the image forming particles. The second element 346 joins the first element 342 and has a generally straight configuration with a thickness T ,. The third element 345 joins the second element 346 and preferably has a symmetrical shape with the first element 342. The third element 345 is defined through the outer radius R'o. The third element 345 has a thickness T'a similar to the thickness of the first element 342. The outlet 334 has a central point Po which is located near the transport roller 390. The central position Po is located adjacent to and outside the periphery 398 of the magnetic roller. The central position Po of the outlet is at a distance Di from the first position 306 of the transport roller 90. The distance Di is significantly smaller than the distance D2 between the center line Pi of the entrance 332 and the first position 306 of the magnetic roller 90.

The air stream 316 enters the inlet 332, passes through the first element 342, then passes through the second element 346 and finally through the third element 345. Then the external air stream 316 exits through the duct 316 in the outlet 334 and joins the magnetic roller 390 on its periphery. The conduit 330 preferably extends from the first end of the magnetic roller 90 to the second end of the magnetic roller 90. The external air stream 316 is directed via the conduit 330 to form a series of recirculation paths within the conduit 330. The trajectories of recirculation greatly reduces the need for new air to enter the developing system 380. Since little new air is added to the housing 344, the pressure within the developing housing 344 can be stabilized and normalized to a pressure substantially similar to ambient pressure . In addition to the problems with the emission of organic pigment from a print developing housing and high volume copying machines, similar problems arise with the emissions of organic pigment in the cleaning of the housings. Similarly to the recirculation channel for a developing housing according to the present invention, a cleaning housing can include a recirculation channel. Referring now to Figure 12, there is shown a cleaning unit 400 that includes a channel 410 according to the present invention. The cleaning unit 400 is used to remove the organic pigment and contaminants from the photoreceptor 10. The cleaning unit 400 normally includes a cleaning housing 444 which defines a cleaning chamber 438 within the cleaning housing 444. The removed organic pigment is axially moved within the chamber 438. The brush 74 contacts the photoreceptor 10 and loosens the remaining organic pigment and the photoreceptor 10 contaminants. Then a cleaning sheet 420 scrapes the organic pigment. The wasted organic pigment and the photoreceptor 10 contaminants are advanced by the sheet 420, the brush 74 and the gravity to a bottle 422 for organic pigment used within the chamber 438 of the housing 444. The photoreceptor 10 on which the Image must be transferred at a high speed. To ensure that the photoreceptor 10 is properly cleaned, the brush 74 must rotate at a sufficient speed to loosen the organic pigment and photoreceptor 10 contaminants. A portion of the organic pigment and contaminants on the photoreceptor 10 are then driven from the brush 74 to the chamber 438 of the cleaning unit 410. A stream 416 of air and particles is created by the brush 74 of the photoreceptor 10 to the sheet 420. The current 416 is diverted to the channel 410. The channel 410 may have any suitable shape for appropriately directing the current 416. For example the channel may include a wall 432 to direct current 416. Preferably the wall is arcuate, for example concave to promote air movement in a circular configuration in the direction of arrow 434. It has been found that the air flow in the channel It is very dependent on the shape of the wall. The optimal form can be determined experimentally or can be modeled by sufficient experimental data of roller speeds and developer forms. Wall 432 can be divided into three areas or elements. These areas preferably include a first element 438 or portion of the wall 432 for receiving the external component 416 of air exiting the sheet area, a second element 440 or portion of the wall 432 for transferring the received air from the first member 436, also as a third element 442 or portion of the wall 432 for transferring the array received from the second element 440 and for expelling the external air 416 to a position adjacent to the brush 74 upstream of the sheet 420. The channel 410 is manufactured of any suitable durable materialfor example metal or plastic sheet and can be integrally molded with the housing 444 of the developer or secured to the developer housing by any suitable method such as by welding, fasteners or by adhesives. To promote uniform air flow, the first element 436 is preferably uniformly combined with the second element 140 at a first transition point. Similarly, the second element 440 is preferably evenly combined with the third element 442 at the second transition point 446. The channel 410 preferably includes a fourth element 450 which extends from a position of the first element 436 to a position close to the third element 442. The fourth element 450 allows channel 410 to form a conduit. The conduit 410 has an inlet 402 and an outlet 404. The air stream 416 enters the inlet 402, makes contact with the wall 432 in the first element 436, is directed by the first element 436 to the second element 440, then is directed by the second element 440 to the third element 442 where it exits through the channel 430 at the outlet 404. The organic pigment expelled, together with the air entrained within the cleaning housing 444 is ejected to the outer edges (not shown) of the housing 444 cleaning. The reduced pressure in the housing 44 prevents the organic pigment and air from escaping from the cleaning housing 444. By using air driven by the moving parts within the housing 444, such as the brush 74 and by recirculating the air within the channel 410, the need to drive more air into the housing 444 is minimized. Figure 13 shows the data collected with and without recirculation chamber inside the cleaner, which indicates the reduction of the internal pressure and hence the dust emissions. Since the pressure within the developer housing 44 of a developing system that includes a channel according to the present invention is much lower than a prior art developer housing, the tendency of the organic pigment particles 82 to leak out of the developer 44 is greatly reduced.

Since the pressure within the cleaning housing 444 of a cleaning unit including a channel according to the present invention is much lower than a cleaning unit of the prior art, the tendency of the organic pigment particles 82 to leak of the cleaning unit 444 is greatly reduced. By providing the channel according to the present invention, the pressures within the developer housing and the cleaning housing can be greatly reduced. By providing a developer housing and a cleaning housing with the channel of the present invention, the reduced pressures within the developer housing and the cleaning housing resulting from the addition of the channel of the present invention greatly reduce pigment leakage The organic housing of the developer housing and the cleaning housing improves the copier's cleanliness, as well as increases the coplatability of the copier with regard to component failures and damage due to the organic pigment particles leaking from the housing of the copier. developer. By using air driven by the moving parts within the developer housing and the cleaning housing, such as the magnetic roller and the brush, respectively, and by recirculating the air within the channel of the developer housing and the channel of the cleaning housing, respectively, the need to push more air into the accommodations is minimized.

The reduced pressure within the revealer housing and the cleaning housing including a channel of the present invention reduces the leakage of organic pigment from the developer housing and the cleaning housing and in particular greatly improves the leakage of the organic pigment for the systems of revealed that they have a higher concentration of organic pigment. The reduced pressure and reduced leakage of the developer housing that includes the channel of the present invention allows the use of more concentrated concentrations of organic pigment within the developer housing and the developer housings with the highest organic pigment concentration may be more compact and less expensive than the larger developer housings required for developer systems with a lower organic pigment concentration and less sensitive to recharge problems. The reduced pressure and reduced leaks of the developer housing and the cleaning housing including the channel of the present invention greatly reduce the danger of seals in the developer housing and the cleaning housing and may allow the use of less expensive seals. and less effective which cause less drag on the developer housing and the cleaning housing and generate less heat. While this invention has been described in conjunction with various modalities, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Therefore, it is proposed to cover all such alternatives, modifications and variations as they fall within the spirit and broad scope of the appended claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following

Claims (30)

1. Claims 1. A channel for recirculating an air stream, located adjacent to a stream of imaging particles that substantially tangentially exits from an image-forming particle transport element, the stream of imaging particles defines an internal boundary thereof that extends tangentially from a first position adjacent to the transport element and that defines an outer boundary thereof spaced from the transport element and the internal boundary, the channel is characterized in that it comprises. a first element, the first element is positioned outside the stream of image formation particles, at least a portion of the first element is positioned substantially adjacent to the outer border of the stream of particles of image formation and spacing of the element Of transport; a second element joined to the first element; and a third element joined to the second element, the second element is positioned adjacent to the transport element and spacing of the stream of image forming particles, substantially all of the air stream being directed by the first element is sequentially directed by the second element. element and the third element.
2. 2. A channel according to claim 1, characterized in that the third element is positioned upstream of the image forming particles.
3. 3. A channel according to claim 1, characterized in that the first element is elongated in a direction substantially parallel to a longitudinal axis of the element.
4. 4. A channel according to claim 1, characterized in that the first element, the second element and the third element are integral with each other.
5. 5. A channel according to claim 1, characterized in that at least a portion of the portion of the first element comprises an arcuate shape.
6. 6. A channel according to claim 1, characterized in that at least a portion of the portion of the third element comprises an arcuate shape.
7. 7. A channel according to claim 1, characterized in that the transport element comprises a magnetic roller.
8. 8. A channel according to claim 1, characterized in that the transport element comprises a cleaning brush.
9. 9. A channel according to claim 1, characterized in that the element is positioned between the portion of the first element and the portion of the third element, close to the portion of the third element and distant from the portion of the first element.
10. 10. A disclosing unit for disclosing a recorded latent image on an image receiving element to form a developed image with imaging particles, characterized in that it comprises: a housing for containing a supply of at least imaging particles; a transport element mounted in the housing for transporting the image forming particles towards the receiving element; and a channel for recirculating a stream of air located adjacent to a stream of image forming particles that exits substantially tangentially from the conveying element, the stream of image forming particles defines an internal boundary thereof which is It extends tangentially from a first position adjacent to the transport element and defines an outer boundary thereof spaced from the transport element and the internal boundary, the channel includes a first element positioned to the outside of the stream of image forming particles, by at least a portion of the first element is positioned substantially adjacent to the outer border of the stream of spaced-apart image formation particles of the transport element, a second element attached to the first element and a third element attached to the second element, the second element is positioned adjacent to the transport element and spacing of the corrie With a plurality of imaging particles, substantially all of the air stream which is directed by the first element is directed sequentially by the second element and the third element.
11. 11. A developing unit according to claim 10, characterized in that the third element is positioned current of the image forming particles.
12. 12. A developing unit according to claim 10, characterized in that the first element is elongated in a direction substantially parallel to a longitudinal axis of the element.
13. 13. A developing unit according to claim 10, characterized in that the first element, the second element and the third element are integral with each other.
14. 14. A developing unit according to claim 10, characterized in that at least a portion of the first element comprises an arcuate shape.
15. 15. A developing unit according to claim 10, characterized in that at least a portion of the third element comprises an arched shape.
16. 16. A developing unit according to claim 10, characterized in that it also comprises a fourth element, located next to the first element, the second element and the third element, to form a channel between them.
17. 17. A developing unit according to claim 10, characterized in that the transport element comprises a magnetic roller.
18. 18. A developing unit according to claim 10, characterized in that the transport element is positioned between the first element and the third element, close to the third element and distant from the first element.
19. 19. A developer unit according to claim 10, characterized in that it further comprises an oil jet element positioned adjacent to the transport element.
20. 20. An electrophotographic printing machine of the type having a developing unit for developing with imaging particles a latent image recorded on an image receiving element, to form a developed image, characterized in that it comprises: a housing for containing a provision of less image formation particles; a transport element mounted in the housing for transporting the image forming particles towards the element receiving the image; and a channel for recirculating an air stream located adjacent to a stream of image forming particles that exit substantially tangentially from the transport element, the stream of image forming particles defines an internal boundary thereof which is It extends tangentially from a first position adjacent to the transport element and defines an outer boundary thereof spaced from the transport element and the internal boundary, the channel includes a first element positioned outside the stream of image forming particles, by at least a portion of the first element is positioned substantially adjacent to the outer border of the stream of spaced-apart image formation particles of the transport element, a second element attached to the first element and a third element attached to the second element, the second element It is positioned adjacent to the transport element and spacing of the co In the case of an image-forming particle stream, substantially all the air stream that is directed by the first element is directed sequentially by the second element and the third element.
21. 21. A printing machine according to claim 20, characterized in that the third element is positioned upstream of the image forming particles.
22. 22. A printing machine according to claim 20, characterized in that the first element is elongated in a direction substantially parallel to a longitudinal axis of the transport element.
23. 23. A printing machine according to claim 20, characterized in that the first element, the second element and the third element are integral with each other.
24. 24. A printing machine according to claim 20, characterized in that at least a portion of the first element comprises an arcuate shape.
25. 25. A printing machine according to claim 20, characterized in that at least a portion of the first element comprises an arcuate shape.
26. 26. A printing machine according to claim 20, characterized in that it also comprises a fourth element located next to the first element, the second element and the third element, to form a channel between them.
27. 27. A printing machine according to claim 20, characterized in that the transport element comprises a magnetic roller.
28. 28. A printing machine according to claim 20, characterized in that the transport element is positioned between the first element and the third element, close to the third element and distant from the first element.
29. 29. A printing machine according to claim 20, characterized in that it also comprises an oil spout element adjacent to the transport element.
30. 30. A cleaning unit for cleaning excess image formation particles from an image receiving element, characterized in that it comprises: a housing for containing a supply of at least excess image formation particles; a cleaning element mounted in the housing for cleaning excess image formation particles from the image receiving element; and a channel for recirculating a stream of air located adjacent to a stream of imaging particles that exits substantially tangentially from the wiper element, the stream of imaging particles defines an inner boundary thereof that extends tangentially from a first position adjacent to the transport element and defining an external boundary thereof spaced from the transport element and the internal boundary, the channel includes a first element positioned to the outside of the stream of image forming particles, so less a portion of the first element is positioned substantially adjacent to the outer border of the stream of spaced and imaged particles of the transport element, a second element attached to the first element and a third element attached to the second element, the second element being positions adjacent to the transport element and spacing of the current of image forming particles, substantially all of the air stream that is directed by the first element is directed sequentially by the second element and the third element.