Paper separator and processor cartridge

A paper separator may be equipped with plurality of paper-separating fingers for separating sheet(s) of paper for image formation and abutting and/or backed off from photosensitive body or bodies, paper separator optionally comprising finger body or bodies capable of abutting photosensitive body or bodies; spur(s)—capable of touching so as to guide sheet(s) of paper for image formation which has or have separated from photosensitive body or bodies; and/or support component(s) pivotably supporting paper-separating finger(s) so as to impart restoring force(s) thereto urging paper-separating finger(s) to under the force(s) of its or their own weight(s) bring finger body or bodies into abutting engagement with photosensitive body or bodies, and so as to, when spur(s) is or are touching sheet(s) of paper for image formation, cause finger body or bodies to at least partially overcome restoring force(s) produced by weight(s) of paper-separating finger(s) or portion(s) thereof and back off from photosensitive body or bodies.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention pertains to a paper separator for separating paper from a photosensitive body or bodies and to a processor cartridge provided therewith for use in copiers and other such electrophotographic image forming apparatuses.

2. Conventional Art

Typical constitutions for electrophotographic image forming apparatuses include, for example, those such as copier1shown inFIG. 13(see Japanese Patent Application Publication Kokai No. H6-27753 (1994)). This copier1is equipped with an optical system10, by means of which an original stage101(glass platen) is irradiated with light, light reflected therefrom exposing a photosensitive body110by way of mirrors102and a lens103; a developer apparatus111, a transfer apparatus112, a cleaning apparatus113, and a charging apparatus114, which are arranged about the photosensitive body110; a fuser apparatus120, which fuses toner transferred onto paper from the photosensitive body110; a discharge tray130, which receives paper from this fuser apparatus120; and a supply apparatus140, which supplies paper to the photosensitive body110.

In accordance with this constitution, paper within the storage cassette141is supplied by a supply roller142, is guided by a U-turn guide143, and is carried by transport rollers144to a point just short of control rollers145(PS roller).

In addition, in synchronous fashion therewith, the original on the original stage101is exposed to light which then travels along an optical path represented by the mirrors102and the lens103to form an image on the photosensitive body110through an electrostatic process, and the electrostatic image formed on the photosensitive body110is made into a toner image by the developer apparatus111.

Furthermore, in order to cause the paper, which had previously stopped in front of the control roller145, to be made to lie directly over the foregoing toner image, the control roller145is made to rotate together with the rotation of the photosensitive body110, causing the paper to be transported onto the surface of the photosensitive body110. In addition, a high-voltage charge produced by the transfer apparatus112acts from the back of the paper which lies against the photosensitive body110and causes the toner image on the photosensitive body110to be transferred to the paper. At such time, due to the high-voltage charge which has been applied to the paper, the paper clings electrostatically to the surface of the photosensitive body110; and in order to separate this therefrom, a paper separator150is provided at a point downstream from the transfer apparatus112in the direction of rotation of the photosensitive body110. Note that atFIG. 13, reference numerals146and147represent guide plates for paper transport.

This paper separator150is equipped with a plurality of paper-separating fingers151, . . . , abutting and/or backed off from photosensitive body110, for separating paper therefrom. Each paper-separating finger151has finger body or bodies at or near the upstream end thereof in the paper transport direction which is or are capable of abutting photosensitive body110, such finger body or bodies being urged to abut the photosensitive body110as a result of restoring force(s) from spring(s). In addition, the paper-separating fingers151are connected to solenoid(s) by way of a plurality of clutch mechanisms and are supported so as to allow movement in direction(s) of engagement and retraction such that driving of the solenoid(s) in synchronous fashion with respect to the control roller145causes finger body or bodies to at least partially overcome restoring force(s) of spring(s) and back off from the photosensitive body110.

Furthermore, other examples of paper separators include those in which paper-separating finger(s) are operated so as to be brought into and out of abutting engagement with photosensitive body or bodies as a result of merely turning solenoid(s) ON and OFF, operations for bringing paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies being such that turning ON and OFF of solenoid(s) is controlled based on processing speed, installation conditions such as humidity and temperature, and the relative tendency for paper to separate from photosensitive body or bodies as determined by type of paper (see, e.g., Japanese Patent Application Publication Kokai No. H14-108110 (2002)).

However, the paper separators described above respectively possess deficiencies such as the following.

To wit, in the first of the two types of paper separator described above, where spring(s) are used to make finger body or bodies of the paper-separating fingers151abut the photosensitive body110, because restoring force(s) from spring(s) cause finger body or bodies to press firmly against the photosensitive body110, the surface of the photosensitive body110become scratched, leading to deterioration of the photosensitive body110. Even where such effect of paper-separating fingers does not represent a problem while the photosensitive body110is in its initial state, there is no disputing that the effect thereof on images will become apparent with continued use, leading to decrease in quality of the images formed therewith. Moreover, special-purpose solenoids are required for operating paper-separating fingers so as to bring them into and out of abutting engagement with photosensitive body or bodies, making increase in the size of the paper separator unavoidable.

Furthermore, in the second of the two types of paper separator described above, where the turning ON and OFF of solenoids is controlled, control circuits are required for accurate timing with respect to turning ON and OFF of solenoids, in order to carry out control based on processing speed, installation conditions, and relative tendency for paper to separate from photosensitive body or bodies, increasing cost. Moreover, where solenoids are used for operations causing paper-separating finger(s) to come into and out of abutting engagement with photosensitive body or bodies, because such operations themselves require a certain amount of time after the start of paper transport, in instances where a multifeed event has occurred at the supply unit (referring to a situation in which the leading edge of a subsequently transported sheet of paper is dragged along by a previously transported sheet of paper, causing it to move to a location forward of its normal position) or where intervals between successive sheets grow small due to slippage of transport rollers or the like, it is difficult to compensate for same by controlling solenoids, contributing to occurrence of jams.

SUMMARY OF INVENTION

The present invention was conceived in light of such issues, it being an object thereof to provide a paper separator making it possible to as much as possible prevent scratching of the photosensitive body surfaces due to contact therewith by finger bodies, achieve reduction in size and decrease in cost of the paper separator, as well as accommodate changes in paper transport speed, and a processor cartridge equipped therewith for image forming apparatuses.

In order to achieve the foregoing object and/or other objects, one or more embodiments of the present invention may be predicated upon a paper separator comprising a plurality of paper-separating fingers abutting and/or backed off from photosensitive body or bodies, for separating paper therefrom. Moreover, one or more embodiments of the present invention may further comprise one or more finger bodies, provided at or near one or more upstream ends in one or more paper transport directions of at least one of the paper-separating fingers, and capable of abutting at least one of the photosensitive body or bodies; one or more guide members, provided at or near one or more downstream ends in one or more paper transport directions of at least one of the paper-separating fingers, and capable of touching so as to guide one or more sheets of paper which has or have separated from at least one of the photosensitive body or bodies; and one or more support components pivotably supporting at least one of the paper-separating fingers so as to impart one or more restoring forces thereto urging at least one of the paper-separating fingers to, under the force of its own weight, bring at least one of the finger body or bodies into abutting engagement with at least one of the photosensitive body or bodies, and so as to, when at least one of the guide member or members is touching at least one of the sheet or sheets of paper, cause at least one of the finger body or bodies to at least partially overcome one or more restoring forces produced by the weight of at least a portion of at least one of the paper-separating fingers and back off from at least one of the photosensitive body or bodies.

As a result of such specific features, because paper-separating finger(s) cause finger body or bodies to abut photosensitive body or bodies under the force(s) of the weight(s) of paper-separating finger(s) or portion(s) thereof, such force(s) being small, it is possible to cause finger body or bodies to press lightly against photosensitive body or bodies, to as much as possible prevent scratching of photosensitive body surface(s), and to suppress deterioration of photosensitive body or bodies. Moreover, due to the light force(s) with which paper-separating finger(s) press against photosensitive body or bodies under the force(s) of its or their own weight(s), such effect of paper-separating finger(s) thereon presents almost no problem, and as no effect thereof becomes apparent on images with continued use, it is possible to effectively prevent decrease in quality of the images formed therewith. In addition, special-purpose solenoid(s) for operating paper-separating finger(s) so as to bring it or them into and out of abutting engagement with photosensitive body or bodies are unnecessary, making it possible to decrease the size of the paper separator.

Furthermore, because, when guide member(s) is or are touching sheet(s) of paper, finger body or bodies of paper-separating finger(s) at least partially overcome restoring force(s) produced by weight(s) of paper-separating finger(s) or portion(s) thereof and back off from photosensitive body or bodies, it is possible for engagement and/or retraction operations to be carried out accurately and in correspondence to paper transport conditions. For this reason, there is no need for control circuits which carry out control based on processing speed, installation conditions, and relative tendency for paper to separate from photosensitive body or bodies, such as is the case where operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies are carried out by controlling the turning ON and OFF of solenoids. As a result, it is possible to achieve reduction in cost of the paper separator.

Moreover, since it is possible to carry out operations causing engagement and/or retraction of paper-separating finger(s) based on whether sheet(s) of paper are touching and/or are not touching guide member(s), unlike the situation in cases where solenoids are used for operations causing engagement and retraction of paper-separating finger(s), a certain amount of time is not required after the start of paper transport for the operations themselves, so it is possible to adequately compensate despite occurrence of any change in interval(s) between successive sheets as a result of multifeed event(s) and/or transport slippage.

Here, where support component(s) are provided between guide member(s) and finger body or bodies of paper-separating finger(s), operations bringing paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies can be carried out smoothly, with support component(s) serving as pivot(s), without unnatural or forced action.

In particular, the following may be presented as exemplary constitutions specifically limiting engagement and/or retraction operations of paper-separating finger(s).

To wit, paper-separating finger(s) may be arranged alongside photosensitive body or bodies in direction(s) perpendicular to paper transport direction(s), operations bringing respective finger bodies into and out of abutting engagement with photosensitive body or bodies being carried out in mutually independent fashion.

As a result of such specific features, because operations causing engagement and/or retraction of paper-separating finger(s) can be carried out in mutually independent fashion, constitution of the paper separator as well as constitution of the individual paper-separating finger(s) is made simple, making it possible to achieve structural simplification.

In contrast, where operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies are carried out in mutual cooperation, when small-size paper is transported therethrough, operations causing engagement and/or retraction of paper-separating finger(s) corresponding to region(s) occupied by the paper as it is transported therethrough are simultaneously accompanied by operations causing engagement and/or retraction of paper-separating finger(s) in region(s) not occupied by (i.e., outside of the path of) the paper as it is transported therethrough, making it possible to effectively suppress scratching of photosensitive body or bodies and/or progress of unnecessary deterioration in regions of photosensitive body or bodies not occupied by (i.e., outside of the path of) the paper.

Moreover, where each of at least two of the paper-separating fingers has support component(s), and operations bringing at least a portion of the finger bodies of the at least two paper-separating fingers into and out of abutting engagement with photosensitive body or bodies are carried out in mutual cooperation due to action of shaft(s) mutually connecting at least a portion of the support components of the at least two paper-separating fingers, it is possible to cause engagement and/or retraction operations in which a plurality of paper-separating fingers cooperate to be carried out smoothly and through employment of an extremely simple constitution.

In particular, the following may be presented as exemplary constitutions specifically limiting amounts of movement at either end of paper-separating finger(s) during engagement and/or retraction operations.

To wit, support component(s) of paper-separating fingers may be disposed at location(s) such as will cause amount(s) by which finger body or bodies move in direction(s) of engagement with and/or retraction from photosensitive body or bodies to be less than amount(s) by which guide member(s) move when it or they touch sheet(s) of paper.

As a result of such specific features, even where amounts by which guide member(s) move due to the force of contact by paper, which force acts on guide member(s) when it or they guide paper traveling therethrough, are small, it will be possible to definitively cause finger body or bodies to back off from photosensitive body surface(s).

In particular, the following may be presented as exemplary constitutions specifically limiting material(s) at prescribed location(s) of paper-separating finger(s).

To wit, guide member(s) may be at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s) used to develop latent electrostatic image(s) on photosensitive body or bodies.

As a result of such specific features, because guide member(s) is or are at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s), even where guide member(s) touch unfused toner image(s) on paper, clinging of toner to guide member(s) is suppressed, making it possible to effectively prevent contamination of paper due to toner clinging to guide member(s).

Furthermore, where finger body or bodies is or are at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s) used to develop latent electrostatic image(s) on photosensitive body or bodies, toner residue on photosensitive body or bodies will not electrostatically adhere to finger body or bodies, and it will be possible to prevent soiling of paper resulting from offsetting thereto by toner clinging to finger body or bodies. Furthermore, it will also be possible to prevent occurrence of the phenomenon whereby unfused toner on paper is electrostatically drawn to finger body or bodies when paper comes in contact with or passes near finger body or bodies. That is, where a finger body is formed from a material of a charge polarity which is different from and opposite to that of toner, existence of a certain degree of difference in density of toner on a photosensitive body will result in a situation in which layered toner at high-density locations comes free of the photosensitive body and adheres to the finger body, giving rise to the problem whereby toner adhering to this finger body is then transferred to the front in the paper transport direction thereof due to the high-voltage charge produced by the transfer apparatus and acting from behind the paper, but where finger body or bodies is or are at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s), toner will not come free of photosensitive body or bodies and adhere to finger body or bodies, and toner image(s) on photosensitive body or bodies will be accurately transferred to paper.

As a result, there being no occurrence of smears on paper due to situations where toner at high-density locations comes off of photosensitive body or bodies and toner adhering to finger body or bodies is transferred to the front in the paper transport direction thereof, and there being no soiling of paper due to situations where toner residue left on photosensitive body or bodies adheres to finger body or bodies, formation of images which are sharp in terms of density variation is made possible.

In particular, the following may be presented as exemplary constitutions specifically limiting guide member(s).

To wit, employed as guide member(s) there may be star-ring-type spur(s) rotatably supported at or near downstream end(s) in paper transport direction(s) of paper-separating finger(s).

As a result of such specific features, surface area over which contact is made with paper during guiding of paper is made small, and it is possible to as much as possible suppress adverse consequences to unfused toner image(s) on paper being transported therethrough notwithstanding the fact that finger body or bodies may be backed off from photosensitive body surface(s).

In particular, the following may be presented as exemplary constitutions in which operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies can be carried out in stable fashion.

To wit, paper separator(s) may further comprise electrostatic clinging prevention means for, during operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies, at least partially preventing electrostatic clinging between paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s); for example: paper-separating finger(s), or member(s) coming in contact with such paper-separating finger(s), or both paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), may be formed from antistatic material(s); antistatic treatment(s) may be applied to paper-separating finger(s), or member(s) coming in contact with such paper-separating finger(s), or both paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s); surface resistance(s) of paper-separating finger(s), or member(s) coming in contact with such paper-separating finger(s), or both paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), may be set to value(s) which is or are not more than 1013Ω; and/or charge-removing member(s) may be provided in the vicinity or vicinities of region(s) where paper-separating finger(s) come in contact with member(s) coming in contact with such paper-separating finger(s).

Were charge allowed to accumulate as paper to which charge has been transferred passes through vicinity or vicinities of finger body or bodies, paper-separating finger(s) would cling electrostatically to member(s) coming in contact with such paper-separating finger(s), interfering with ability of finger body or bodies of paper-separating finger(s) to come into abutting engagement with photosensitive body or bodies; but as a result of the foregoing specific features, presence of electrostatic clinging prevention means—such as the fact that paper-separating finger(s), or member(s) coming in contact with such paper-separating finger(s), or both paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), may be formed from antistatic material(s); and/or antistatic treatment(s) may be applied thereto; and/or surface resistance(s) thereof may be set to value(s) which is or are not more than 1013Ω; and/or the fact that charge-removing member(s) may be provided in the vicinity or vicinities of region(s) where paper-separating finger(s) come in contact with member(s) coming in contact with such paper-separating finger(s)—makes it possible to prevent occurrence of electrostatic clinging between paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), making it possible for operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies to be carried out in stable fashion and permitting attainment of more assured tendency for paper to separate from photosensitive body or bodies as a result of action of paper-separating finger(s).

In particular, the following may be presented as exemplary constitutions of processor cartridges for image forming apparatus(es) provided with paper separator(s) as described above.

To wit, at least paper-separating finger(s) and photosensitive body or bodies may be constructed so as to permit installation and removal in integral fashion with respect to image forming apparatus(es).

As a result of such specific features, not only are the cams and connecting linkages, electrical components and harnesses, and other such superfluous mechanism components which had been required for engagement and/or retraction operations performed by paper-separating finger(s) completely eliminated, permitting facilitation of procedures for installation of processor cartridge(s) in image forming apparatus(es) and removal of same therefrom, but it is also possible to effectively prevent breakage of components, faulty operation, and/or other such problems accompanying procedures for installation and/or removal.

Moreover, where photosensitive body or bodies is or are constructed so as to permit installation and/or removal thereof with respect to paper-separating finger(s), and paper-separating finger(s) is or are acted upon by restoring force(s) produced by the force(s) of its or their own weight(s) and causing finger body or bodies to back off from photosensitive body or bodies when processor cartridge(s) is or are made to assume orientation(s) permitting installation and/or removal of photosensitive body or bodies, because paper-separating finger(s), under the force(s) of its or their own weight(s), cause finger body or bodies to back off from photosensitive body or bodies when processor cartridge(s) is or are made to assume orientation(s) permitting installation and/or removal of photosensitive body or bodies, contact between photosensitive body or bodies and finger body or bodies of paper-separating finger(s) is avoided during photosensitive body installation and/or removal procedure(s), making it possible to effectively prevent scratching of photosensitive body surface(s), breakage or the like of finger body or bodies, and so forth.

One or more embodiments of the present invention as described above may provide one or more of the following benefits. By causing finger body or bodies of paper-separating finger(s) to abut photosensitive body or bodies under the force(s) of the weight(s) of paper-separating finger(s) or portion(s) thereof, such force(s) being small, it is possible to cause finger body or bodies to press lightly against photosensitive body or bodies, to as much as possible prevent scratching of photosensitive body surface(s), and to suppress deterioration of photosensitive body or bodies, and furthermore, to effectively prevent decrease in quality of the images formed therewith. By making it unnecessary to employ special-purpose solenoid(s) for operating paper-separating finger(s) so as to bring it or them into and out of abutting engagement with photosensitive body or bodies, it is possible to decrease the size of the paper separator. By, when guide member(s) is or are touching sheet(s) of paper, causing finger body or bodies of paper-separating finger(s) to at least partially overcome restoring force(s) produced by weight(s) of paper-separating finger(s) or portion(s) thereof and back off from photosensitive body or bodies, it is possible for engagement and/or retraction operations to be carried out accurately and in correspondence to paper transport conditions; there is no need for control circuits for turning solenoids ON and OFF based on processing speed, installation conditions, and relative tendency for paper to separate from photosensitive body or bodies; and it is possible to achieve reductions in paper separator cost. And where it is possible to carry out operations causing engagement and/or retraction of paper-separating finger(s) based on whether sheet(s) of paper are touching and/or are not touching guide member(s), it will be possible to adequately accommodate any change in interval(s) between successive sheets as a result of multifeed event(s) and/or transport slippage.

By providing support component(s) between guide member(s) and finger body or bodies of paper-separating finger(s), engagement and/or retraction operations in which support component(s) of paper-separating finger(s) serve as pivot(s) can be carried out smoothly and without unnatural or forced action.

By carrying out operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies in mutually independent fashion, it is possible to achieve structural simplification with respect to constitution of paper separator(s) as well as that of individual paper-separating finger(s).

In contrast, by carrying out operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies in mutual cooperation, operations causing engagement and/or retraction of paper-separating finger(s) when small-size paper is transported therethrough can be simultaneously accompanied by operations causing engagement and/or retraction of paper-separating finger(s) in region(s) not occupied by the paper as it is transported therethrough, making it possible to effectively suppress scratching of photosensitive body or bodies and/or progress of unnecessary deterioration in region(s) of photosensitive body or bodies not occupied by the paper.

By, where each of at least two of the paper-separating fingers has support component(s), carrying out operations bringing at least a portion of the finger bodies of the at least two paper-separating fingers into and out of abutting engagement with photosensitive body or bodies in mutual cooperation due to action of shaft(s) mutually connecting at least a portion of the support components of the at least two paper-separating fingers, it is possible to cause engagement and/or retraction operations in which a plurality of paper-separating fingers cooperate to be carried out smoothly and through employment of an extremely simple constitution.

By causing amount(s) by which finger body or bodies move in direction(s) of engagement with and/or retraction from photosensitive body or bodies to be less than amount(s) by which guide member(s) move when it or they touch sheet(s) of paper, even where amount(s) by which guide member(s) move during guiding of paper are small it will be possible to definitively cause finger body or bodies to back off from photosensitive body surface(s).

By causing guide member(s) to be at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s), clinging of toner to guide member(s) when guide member(s) touch unfused toner image(s) on paper is suppressed, making it possible to effectively prevent contamination of paper due to toner clinging to guide member(s).

By causing finger body or bodies to be at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s), it will be possible to prevent toner from coming free of photosensitive body or bodies and adhering to finger body or bodies, and to prevent smears due to transfer to the front thereof in the paper transport direction and/or soiling of paper due to the fact that toner residue on photosensitive body or bodies is made to adhere to finger body or bodies, and it will be possible to form images which are sharp in terms of density variation.

By employing rotatable star-ring-type spur(s) as guide member(s), surface area over which contact is made with paper can be made small, and it will be possible to as much as possible suppress adverse consequences to unfused toner image(s) on paper being transported therethrough.

By, during operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies, preventing occurrence of electrostatic clinging between paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s) through employment of electrostatic clinging prevention means—such as the fact that paper-separating finger(s), or member(s) coming in contact with such paper-separating finger(s), or both paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), may be formed from antistatic material(s); and/or antistatic treatment(s) may be applied thereto; and/or surface resistance(s) thereof may be set to value(s) which is or are not more than 1013Ω; and/or the fact that charge-removing member(s) may be provided in the vicinity or vicinities of region(s) where paper-separating finger(s) come in contact with member(s) coming in contact with such paper-separating finger(s)—it is possible to prevent occurrence of electrostatic clinging between paper-separating finger(s) and member(s) coming in contact with such paper-separating finger(s), at which there is a tendency for charge to accumulate as paper to which charge has been transferred passes therethrough, permitting operations bringing finger body or bodies of paper-separating finger(s) into and out of abutting engagement with photosensitive body or bodies to be carried out in stable fashion, and permitting attainment of more assured tendency for paper to separate from photosensitive body or bodies as a result of action of paper-separating finger(s).

By constructing at least paper-separating finger(s) and photosensitive body or bodies so as to permit installation and removal in integral fashion with respect to image forming apparatus(es) and employing same as the aforementioned processor cartridge(s) for image forming apparatus(es) provided with paper separator(s), it is possible to completely eliminate superfluous mechanism components which would otherwise be required for engagement and/or retraction operations performed by paper-separating finger(s), permitting facilitation of procedures for installation of processor cartridge(s) in image forming apparatus(es) and removal of same therefrom, and also making it possible to effectively prevent breakage of components, faulty operation, and/or other such problems accompanying procedures for installation and/or removal.

By causing finger body or bodies of paper-separating finger(s) to, under the force(s) of the weight(s) of paper-separating finger(s) or portion(s) thereof, back off from photosensitive body or bodies when processor cartridge(s) is or are made to assume orientation(s) permitting installation and/or removal of photosensitive body or bodies, it is possible to avoid contact between photosensitive body or bodies and finger body or bodies of paper-separating finger(s) during photosensitive body installation and/or removal procedure(s), making it possible to effectively prevent scratching of photosensitive body surface(s), breakage or the like of finger body or bodies, and so forth.

DESCRIPTION OF THE PRESENT INVENTION

Below, the best modes of carrying out the present invention are described with reference to the drawings.

First Embodiment

Description of the first embodiment is carried out in terms of a situation in which a paper separator associated with the present invention is installed in a digital copier.

—Description of Overall Constitution of Copier—

FIG. 1shows in schematic fashion the internal constitution of a copier2which serves as an image forming apparatus associated with the present embodiment. As shown inFIG. 1, the present copier2is provided with a scanning unit20, a printing unit30, and an automatic original feed unit40. Moreover, this scanning unit20and this automatic original feed unit40constitute an image capturing apparatus. Description of the respective units follows below.

At the subassembly represented by the scanning unit20, images of originals placed on an original stage410comprising transparent glass or the like and/or images of originals fed one at a time from the automatic original feed unit40are captured and image data is created. This scanning unit20is provided with an exposing light source210; a plurality of reflecting mirrors220,230,240; an imaging lens250; and a photoelectric conversion element (CCD=charge coupled device)260.

The aforementioned exposing light source210causes light to be irradiated onto the originals placed on the original stage410of the automatic original feed unit40and/or the originals transported thereto by the automatic original feed unit40. As indicated by the optical axis depicted using a dashed line atFIG. 1, respective reflecting mirrors220,230,240cause light reflected from the original to first be reflected to the left as shown in the drawing, to thereafter be reflected downward, and to thereafter be reflected to the right as shown in the drawing so as to be directed toward the imaging lens250.

Operations for capturing the original image are such that, in the situation where the original is placed on the aforementioned original stage410(i.e., stationary sheet operation), the exposing light source210and reflecting mirror220scan horizontally in parallel fashion with respect to the original stage410from a position indicated by the solid line inFIG. 1to a position indicated by the imaginary line therein so as to capture an image of the entire original. On the other hand, in the situation where the original is transported by the automatic original feed unit40(i.e., moving sheet operation), the exposing light source210and the reflecting mirror220remain stationary at a position as indicated by the solid line inFIG. 1, and the original capturing unit420of the automatic original feed unit40, described below, is made to capture an image of the original when the original passes therethrough. Moreover, this original capturing unit420comprises a glass platen420a, described below; an original backpressure plate420b; the exposing light source210; the reflecting mirrors220,230,240; the imaging lens250; and the photoelectric conversion element260.

Light reflected by the aforementioned respective reflecting mirrors220,230,240and passing through the imaging lens250is guided to photoelectric conversion element260, the reflected light being converted into electrical signal(s) (original image data) at this photoelectric conversion element260.

—Description of Printing Unit30—

The printing unit30is provided with an image forming system310and a paper transport system320.

The image forming system310is provided with a laser scanning unit310aand a drum-type photosensitive body310b. The laser scanning unit310airradiates the surface of the photosensitive body310bwith laser light based on the original image data produced by conversion at the aforementioned photoelectric conversion element260. The photosensitive body310brotates in the direction indicated by the arrow inFIG. 1, and a latent electrostatic image is formed on the surface thereof as a result of irradiation thereof by laser light from laser scanning unit310a.

Furthermore, arranged in order in a circumferential direction peripheral and exterior to the photosensitive body310bthere are—in addition to the aforementioned laser scanning unit310a—developer apparatus310c, a transfer charging apparatus310d, a paper separator311, a cleaning apparatus310e(shown inFIGS. 3 and 4), a main charging unit310f, and so forth. The developer apparatus310cuses toner to develop the latent electrostatic image formed on the surface of the photosensitive body310band produces a visible image. The transfer charging apparatus310dtransfers the toner image formed on the surface of the photosensitive body310bonto paper100for image formation, which serves as paper. The cleaning apparatus310eremoves toner residue from the surface of the photosensitive body310bfollowing toner transfer. The paper separator311abuts and/or is backed off from the photosensitive body310band, by virtue of its abutting engagement with the photosensitive body310b, causes the paper100for image formation, which clings electrostatically to the surface of the photosensitive body310bdue to the high-voltage charge produced by the transfer charging apparatus310dand acting from the back of paper100for image formation, to be separated from the surface of said photosensitive body310b. This paper separator311is provided at a point downstream from the transfer charging apparatus310din the direction of rotation of the photosensitive body310b. The main charging unit310fcharges the surface of the photosensitive body310bto a prescribed electrical potential prior to formation of the latent electrostatic image.

When forming an image on paper100for image formation, therefore, the main charging unit310fcauses the surface of the photosensitive body310bto be charged to a prescribed electrical potential, and the laser scanning unit310airradiates the surface of the photosensitive body310bwith laser light based on the original image data. The developer apparatus310cthen develops a visible toner image on the surface of the photosensitive body310b, and the transfer charging apparatus310dcauses the toner image to be transferred to paper100for image formation. Moreover, toner residue on the surface of the photosensitive body310bis thereafter removed by the cleaning apparatus. This concludes one cycle of image forming operations (printing operations) which are carried out on paper100for image formation. By repeating this cycle, it is possible to continuously carry out image formation on a plurality of sheets of paper100,100, . . . for image formation.

Furthermore, the paper transport system320transports paper100,100, . . . for image formation one sheet at a time from where it is stored in a paper cassette330and/or a paper tray340so as to permit image formation by the aforementioned image forming system310, and also discharges paper100for image formation to a discharge tray350after image(s) have been formed thereon.

This paper transport system320is provided with a main transport path360and a flipping transport path370. One end of the main transport path360opposes the discharge tray350, and the other end thereof branches into two subpaths, the two subpaths respectively opposing the discharge sides of the paper cassette330and the paper tray340. One end of the flipping transport path370is connected to the main transport path360at a point downstream from (above, in the drawing) the location at which the transfer charging apparatus310dis installed, and the other end thereof is connected to the main transport path360at a point upstream from (below, in the drawing) the location at which the transfer charging apparatus310dis installed.

Arranged at the upstream end of the main transport path360(at regions opposing the discharge sides of the paper cassette330and paper tray340) are pickup rollers360a,360ahaving semicircular cross-sections. Arranged immediately downstream of these pickup rollers360a,360aare supply rollers360b,360b. The rotation of these pickup rollers360a,360aand the supply rollers360b,360bpermits paper100,100, . . . for image formation to be supplied in intermittent fashion, one sheet at a time, from where it is stored in the paper cassette330and/or the paper tray340to the main transport path360.

Arranged at a point upstream from the location at which the transfer charging apparatus310dis installed in this main transport path360is a pair of registration rollers360d,360d. These registration rollers360d,360dtransport paper100for image formation while aligning paper100for image formation with the toner image on the surface of the photosensitive body310b. Provided at a point downstream from the location at which the transfer charging apparatus310dis installed in this main transport path360is a fuser apparatus39, which fuses the toner image transferred onto paper100for image formation. This fuser apparatus39comprises a fusing roller391, which is provided with a halogen lamp at the interior thereof as heat source; and a pressure roller392, which presses against this fusing roller391. By heating and compressing the paper100for image formation between the fusing roller391and the pressure roller392as it is transported therethrough, the fusing roller391and the pressure roller392cause the toner on paper100for image formation to melt, fusing the toner image on paper100for image formation.

Arranged at a location at the top end of the flipping transport path370, where the flipping transport path370joins the main transport path360, is a diverter paddle380. This diverter paddle380is capable of being rotated about a horizontal axis from a first position indicated by the solid line inFIG. 1to a second position indicated by the imaginary line (double-dash chain line) therein. When this diverter paddle380is in its first position, paper100for image formation is discharged to the discharge tray350; and when it is in its second position, paper100for image formation is supplied to the flipping transport path370. Transport rollers370a,370a, . . . are arranged at a plurality of locations in the flipping transport path370; and when paper100for image formation is supplied to the flipping transport path370, paper100for image formation is transported by these transport rollers370a,370a, . . . , paper100for image formation being flipped at a location upstream of the registration rollers360dand being again transported along the main transport path360toward the transfer charging apparatus310d. That is, arrangements are made to permit image formation to be carried out on the back of paper100for image formation.

—Description of Automatic Original Feed Unit40—

Automatic original feed unit40will next be described.

This automatic original feed unit40is constructed so as to permit it to serve as an “automatic double-sided original transport apparatus.” The aforementioned automatic original feed unit40is capable of being used for moving sheet operation, and is provided with an original tray430; an intermediate tray440; an original discharge tray450; and an original transport system460for transporting originals between respective trays430,440,450.

The aforementioned original transport system460is provided with a main transport path470for transporting originals (not shown) which have been placed in the original tray430to the intermediate tray440and/or the original discharge tray450by way of the original capturing unit420; and an auxiliary transport path480for supplying originals to the main transport path470from the intermediate tray440.

Arranged at the upstream end of the main transport path470(at a region opposing the discharge side of the original tray430) are a pickup roller470aand a separation roller470b. Arranged below this separation roller470bis a separation plate (not shown), and in accompaniment to rotation of the pickup roller470a, one sheet from the original(s) in the original tray430is made to pass between this separation roller470band this separation plate, and is supplied to the main transport path470. Arranged at a location downstream of the intersection of the main transport path470and the auxiliary transport path480are PS rollers470c,470c. These PS rollers470c,470cthat supply originals to the original capturing unit420such that the leading edge of the original is coordinated with the timing with which image capture occurs at the scanning unit20. That is, upon supply of an original thereto, these PS rollers470c,470ctemporarily stop transport of the original so as to permit adjustment of the aforementioned timing before supplying the original to the original capturing unit420.

The original capturing unit420is provided with the glass platen420aand the original backpressure plate420b, and when an original supplied thereto by the PS rollers470c,470cpasses between the glass platen420aand the original backpressure plate420b, light from the aforementioned exposing light source210passes through the glass platen420aand irradiates the original. At this time, acquisition of the original image data by the aforementioned scanning unit20occurs. Provided behind (above) the aforementioned original backpressure plate420bis a coil spring (not shown), this coil spring causing the original backpressure plate420bto press against and contact the glass platen420awith a prescribed force so as to discourage the original from lifting up off of the glass platen420aas the original passes through the original capturing unit420.

Provided downstream of the original capturing unit420are transport rollers470d,470dand original discharge rollers470e,470e. Moreover, the constitution is such that upon passing through the original capturing unit420, originals are discharged to the intermediate tray440and/or the original discharge tray450by way of the transport rollers470d,470dand the original discharge rollers470e,470e.

Arranged between the aforementioned original discharge rollers470eand the intermediate tray440is an intermediate tray pivot plate440a. The pivoting motion of this intermediate tray pivot plate440abeing centered on the end thereof which is nearer to the intermediate tray440, the intermediate tray pivot plate440ais capable of pivoting between a first position indicated by the solid line inFIG. 1and a second position indicated by the dashed line therein. Moreover, when the intermediate tray pivot plate440ais in its first position, originals discharged by original discharge rollers470eare recovered into the original discharge tray450. On the other hand, when the intermediate tray pivot plate440ais in its second position, originals discharged by the original discharge rollers470eare discharged into the intermediate tray440. When an original is discharged to this intermediate tray440due to the fact that the intermediate tray pivot plate440ais in its second position as indicated by the dashed line inFIG. 1, the edge of the original is held in the nip between the original discharge rollers470e,470e; and with the original in this state, original discharge rollers470ethen rotate backwards, causing the original to be supplied to the auxiliary transport path480, and after traveling through this auxiliary transport path480, the original is again delivered to the main transport path470. Operations whereby these original discharge rollers470eare made to rotate backwards are carried out such that delivery of the original to the main transport path470is coordinated with the timing with which image capture occurs. This makes it possible for the original capturing unit420to capture an image of the back of the original.

—Description of Characteristic Features of the Present Invention—

As shown inFIGS. 2 through 4and representing characteristic features of one or more embodiments of the present invention, the aforementioned paper separator311comprises two paper-separating fingers312,312, abutting and/or backed off from the photosensitive body310b, for separating paper100for image formation from photosensitive body310b. These respective paper-separating fingers312are arranged alongside photosensitive body310bin a direction perpendicular to the direction in which paper100for image formation advances as it is transported along the main transport path360toward the transfer charging apparatus310d. Moreover, each of the aforementioned paper-separating fingers312comprises finger body or bodies313, provided at or near the upstream end (the left end inFIG. 2), in the direction in which paper100for image formation is transported along the main transport path360, of the paper-separating finger312, and capable of abutting and/or being backed off from the aforementioned photosensitive body310b; guide member(s)314, provided at or near the downstream end, in the direction in which paper100for image formation is transported along the main transport path360, of the paper-separating finger312, and capable of touching so as to guide paper100for image formation which has separated from the photosensitive body310b; and support component(s)315, provided between the aforementioned finger body or bodies313and the guide member(s)314, and pivotably supporting the paper-separating finger(s)312. In such case, provision of the support component(s)315between the finger body or bodies313and the guide member(s)314makes it possible for operations bringing the paper-separating fingers312into and out of abutting engagement with the photosensitive body310bto be carried out smoothly, with the support component(s)315serving as pivot(s), without unnatural or forced action.

The tip of each of the aforementioned finger bodies313is formed in pointed fashion so as to contact the surface of the photosensitive body310bwithout a gap therebetween, making it possible to smoothly separate from the surface of the photosensitive body310bany paper100for image formation which has clung electrostatically thereto. Furthermore, employed as the guide members314there are star-ring-type spurs314arotatably supported at or near the downstream ends, in the direction of transport of paper100for image formation, of the paper-separating fingers312. In such case, provision of the star-ring-type spurs314aas guide members314makes it possible for the surface area over which contact is made with paper100for image formation during guiding of paper100for image formation to be made small, making it possible to as much as possible suppress adverse consequences to unfused toner image(s) on paper100for image formation being transported therethrough notwithstanding the fact that finger body or bodies313may be backed off from the photosensitive body310b.

Each of the aforementioned support components315has shaft(s)315aextending horizontally and support regions315brotatably supporting such shaft(s)315a, the basal portion of each support region315bbeing attached to support member(s)300beneath the cleaning apparatus310e. In addition, the support components315pivotably support the paper-separating fingers312so as to impart restoring forces thereto urging paper-separating fingers312to, under the respective forces of their own weights, bring finger bodies313into abutting engagement with the photosensitive body310b, and so as to, when the spur(s)314a(guide member(s)314) is or are touching paper100for image formation, cause the finger body or bodies313to at least partially overcome restoring force(s) produced by the weight(s) of the finger body or bodies313or portion(s) thereof and back off from the photosensitive body310b. In such case, as shown inFIG. 5, constructing an imaginary line m between the nip formed by the fusing roller391and the pressure roller392on the one hand and a point between the photosensitive body310band the transfer charging apparatus310don the other, the tip of each spur314a(guide member314) is disposed so as to be at least partially located in a zone to the transfer charging apparatus310d(pressure roller392) side of line m. As a result, when, as shown inFIG. 3, the spur(s)314a(guide member(s)314) do not touch paper100for image formation as it is transported along the main transport path360after separating from the photosensitive body310b, the paper-separating finger(s)312is or are such as to, under the force(s) of its or their own weight(s), hold finger body or bodies313at position(s) causing it or them to abut the photosensitive body310b; but when, as shown inFIG. 4, the spur(s)314a(guide member(s)314) touch so as to guide paper100for image formation as it is transported along the main transport path360after separating from the photosensitive body310b, the paper-separating finger(s)312is or are such that the spur(s)314atouch paper100for image formation as it travels along the aforementioned line m, the paper-separating finger(s)312pivoting so as to raise toward and/or raise so as to bring deeper into the zone to the photosensitive body310b(fusing roller391) side of line m the downstream end(s) (spur(s)314a), in the direction in which paper100for image formation is transported, of the paper-separating finger(s)312, causing the finger body or bodies313to move to position(s) causing it or them to back off from the photosensitive body310b.

Furthermore, the paper-separating fingers312are separately attached by way of the support regions315bat more or less central location(s) on the bottom face(s) of the support member(s)300beneath the cleaning apparatus310eso as to permit operations bringing respective finger body or bodies313into and out of abutting engagement with the photosensitive body310bto be carried out in mutually independent fashion.

In addition, the spurs314a(guide members314) and the finger bodies313are formed from negative-charge-type material(s) of negative charge polarity, e.g., Mulite [Phonetic transliteration of word in Japanese text.—Translator] D-401 (registered trademark) or the like; such material(s) being of negative charge polarity, this being the same as the charge polarity (negative charge polarity) of the toner that develops the latent electrostatic image on the photosensitive body310b.

Moreover, as shown inFIGS. 6 and 7, the aforementioned photosensitive body310b, paper separator311(paper-separating fingers312), and cleaning apparatus310eare housed within a processor cartridge500so as to permit installation and removal in integral fashion with respect to the copier2. Furthermore, the aforementioned processor cartridge500is constructed so as to permit the aforementioned photosensitive body310b, paper separator311, and cleaning apparatus310eto respectively be separately installed therein and/or removed therefrom.

A procedure for installing the photosensitive body310bin the aforementioned processor cartridge500and/or removing same therefrom will now be described.

First, as shown inFIG. 6, in order to remove the photosensitive body310bfrom the processor cartridge500, the processor cartridge500is made to assume an orientation which is such that the cleaning apparatus310eis directly below the photosensitive body310b. At such time, the paper-separating fingers312are acted upon by restoring forces produced by the respective forces of their own weights and urging the finger bodies313to back off from the photosensitive body310b.

A locking cap500aat one end in the axial direction of the photosensitive body310bis then loosened by rotating the same in the direction indicated by the arrow A1, and the locking cap500ais pulled away in the direction of the arrow A2and removed from the photosensitive body310b, following which, as shown inFIG. 7, the photosensitive body310bis pressed against the other end in the axial direction thereof and is then pulled upward (in the direction opposite cleaning apparatus310e) and removed therefrom.

On the other hand, in order to install the photosensitive body310bin processor cartridge500, the foregoing procedure is carried out in reverse order.

Accordingly, in the foregoing embodiment, because the paper-separating fingers312cause the finger bodies313to abut the photosensitive body310bunder the forces of the weights of the paper-separating fingers312or portions thereof, such forces being small, it is possible to cause the finger bodies313to press lightly against the photosensitive body310b, to as much as possible prevent the surface of the photosensitive body310bfrom being scratched, and to suppress deterioration of the photosensitive body310b. Moreover, due to the light forces with which the paper-separating fingers312press against the photosensitive body310bunder the forces of their own weights, such effect of the paper-separating fingers312thereon presents almost no problem, and as no effect thereof becomes apparent on images with continued use, it is possible to effectively prevent decrease in quality of the images formed therewith. In addition, it is unnecessary to employ special-purpose solenoid(s) for operating the paper-separating fingers312so as to bring them into and out of abutting engagement with the photosensitive body310b, making it possible to decrease the size of the paper separator311.

Furthermore, because, when the spurs314a(guide members314) touch paper100for image formation as it is transported along the main transport path360after separating from the photosensitive body310b, the finger bodies313of the paper-separating fingers312at least partially overcome restoring forces produced by weights of the paper-separating fingers312or portion(s) thereof and back off from the photosensitive body310b, it is possible for engagement and/or retraction operations to be carried out accurately and in correspondence to paper100for image formation transport conditions. For this reason, there is no need for control circuits which carry out control based on processing speed, installation conditions, and relative tendency for paper to separate from photosensitive body or bodies, such as is the case where operations bringing the finger body or bodies of the paper-separating finger(s) into and out of abutting engagement with the photosensitive body or bodies are carried out by controlling the turning ON and OFF of solenoids. As a result, it is possible to achieve reduction in cost of the paper separator311.

Moreover, since it is possible to carry out operations causing engagement and/or retraction of the paper-separating fingers312based on whether paper100for image formation is touching and/or is not touching the spurs314a(guide members314), unlike the situation in cases where solenoids are used for operations causing engagement and retraction of the paper-separating finger(s), a certain amount of time is not required after the start of paper transport for the operations themselves, and so it is possible to adequately compensate despite occurrence of any change in interval(s) between successive sheets as a result of multifeed event(s) and/or transport slippage.

Moreover, because operations causing engagement and/or retraction of respective paper-separating fingers312can be carried out individually and in mutually independent fashion, constitution of the paper separator311as well as constitution of the individual paper-separating fingers312is made simple, making it possible to achieve structural simplification.

Guide member(s) may be at least partially formed from material(s) of the same charge polarity or polarities as that or those of toner(s) used to develop latent electrostatic image(s) on the photosensitive body or bodies.

Moreover, because the finger bodies313and the spurs314aof the paper-separating fingers312are formed from negative-charge-type material(s) of negative charge polarity, e.g., Mulite [Phonetic transliteration of word in Japanese text.—Translator] D-401 (registered trademark) or the like—such material(s) being of negative charge polarity, this being the same as the charge polarity (negative charge polarity) of the toner that develops the latent electrostatic image on the photosensitive body310b—even where the spur(s)314atouch unfused toner image(s) on paper100for image formation, clinging of toner to the spur(s)314ais suppressed, making it possible to effectively prevent contamination of paper100for image formation due to toner clinging to the spur(s)314a.

Also, where the finger body or bodies313is or are at least partially formed from negative-charge-type material(s) of negative charge polarity, this being the same as the charge polarity of the toner, toner residue on the photosensitive body310bwill not electrostatically adhere to the finger body or bodies313, and it will be possible to prevent soiling of paper100for image formation resulting from offsetting thereto by toner clinging to the finger body or bodies313. Furthermore, it will also be possible to prevent occurrence of the phenomenon whereby unfused toner on paper100for image formation is electrostatically drawn to the finger body or bodies313when paper100for image formation comes in contact with or passes near the finger body or bodies313. This is because, where the finger body313is formed from a material of a charge polarity which is different from and opposite to that of toner, existence of a certain degree of difference in density of toner on the photosensitive body will result in a situation in which layered toner at high-density locations comes free of the photosensitive body and adheres to the finger body, giving rise to the problem whereby toner adhering to this finger body is then transferred to the front in the paper transport direction thereof due to the high-voltage charge produced by the transfer apparatus and acting from behind the paper, but where the finger body or bodies313is or are at least partially formed from material(s) of negative charge polarity, this being the same charge polarity as that of the toner, the toner will not come free of the photosensitive body310band adhere to the finger body or bodies313, and toner image(s) on the photosensitive body310bwill be accurately transferred to paper100for image formation. As a result, there being no occurrence of smears on paper100for image formation due to situations where toner at high-density locations comes off of the photosensitive body310band toner adhering to the finger body or bodies313is transferred to the front thereof in the direction in which paper100for image formation is transported, and there being no soiling of paper100for image formation due to situations where toner residue left on the photosensitive body310badheres to the finger body or bodies313, formation of images which are sharp in terms of density variation is made possible.

Moreover, because at least the photosensitive body310b, the paper separator311(paper-separating fingers312) and the cleaning apparatus310eare housed in the processor cartridge500so as to permit installation and removal in integral fashion with respect to the copier2, cams and connecting linkages, electrical components and harnesses, and other such superfluous mechanism components which would otherwise be required for engagement and/or retraction operations performed by the paper-separating fingers312are completely eliminated, permitting facilitation of the procedures for installation of processor cartridge500in copier2and removal of same therefrom, and also making it possible to effectively prevent breakage of components, faulty operation, and/or other such problems accompanying procedures for installation and/or removal. Furthermore, because the processor cartridge500is constructed such that photosensitive body310b, the paper separator311, and the cleaning apparatus310ecan respectively be separately installed in and/or removed therefrom, and because the paper-separating fingers312, under the forces of their own weights, cause the finger bodies313to back off from the photosensitive body310bwhen the processor cartridge500is made to assume orientation(s) permitting installation and/or removal of the photosensitive body310b, contact between the photosensitive body310band the finger bodies313of the paper-separating fingers312is avoided during procedure(s) for installation and/or removal of the photosensitive body310b, making it possible to effectively prevent scratching of the surface of the photosensitive body310b, breakage or the like of the finger bodies313, and so forth.

Note that whereas, in the foregoing first embodiment, the paper separator311was provided with two paper-separating fingers312,312, a paper separator510may be provided in which, as shown inFIG. 8, four paper-separating fingers312, . . . are arranged alongside the photosensitive body310bin a direction perpendicular to the direction in which paper100for image formation advances as it is transported along the main transport path360. In such case, the paper-separating fingers312, . . . might be arranged across the entire zone occupied by the paper at the photosensitive body310b, permitting more definitive separation of paper100for image formation from the surface of the photosensitive body310bwhen papers100for image formation of different size are transported along the main transport path360.

Second Embodiment

Next, referring toFIG. 9, a second embodiment of the present invention is described.

In the present embodiment, constitution(s) of paper-separating finger(s) are modified. Note that, except for the paper-separating fingers, the constitution is in other respects identical to that of the foregoing first embodiment, and like components will be assigned like reference numerals and detailed description thereof will be omitted.

To wit, as shown inFIG. 9, in the present embodiment, support component(s)521for paper-separating finger(s)520has or have shaft(s)521aextending horizontally and support region(s)521brotatably supporting such shaft(s)521a, the basal portion of each support region521bbeing attached to support member(s)300beneath the cleaning apparatus310e. Note that reference numeral521bis or are support member(s) which rotatably support shaft(s)521a.

In addition, the aforementioned support component(s)521are disposed at location(s) such as will cause amount(s) by which finger body or bodies522move in direction(s) of engagement with and/or retraction from the photosensitive body310bto be less than amount(s) by which spur(s)523move when it or they touch paper100for image formation.

More specifically, distance H from axis p of the shaft521aof the support component521to axis q of a shaft523aof the spur523is set so as to be twice as large as distance L from axis p of the shaft521aof the support component521to the tip of the finger body522.

As a result, even where the amount by which the spur523moves in the direction of the arrow due to the force of contact by paper100for image formation, which force acts on spur523when it guides paper100for image formation as paper100for image formation is transported along the main transport path360after separating from the photosensitive body310b, is small, it will nonetheless be possible to definitively cause the finger body522to back off from the surface of the photosensitive body310b.

Third Embodiment

Next, referring toFIG. 10, a third embodiment of the present invention is described.

In the present embodiment, constitution(s) of support component(s) of paper-separating finger(s) are modified. Note that, except for the support component(s), the constitution is in other respects identical to that of the foregoing first embodiment, and like components will be assigned like reference numerals and detailed description thereof will be omitted.

That is, as shown inFIG. 10, the present embodiment is provided with a paper separator530in which four paper-separating fingers312, . . . are arranged alongside the photosensitive body310bin a direction perpendicular to the direction in which paper100for image formation advances as it is transported along the main transport path360.

In addition, support components531for each set of two paper-separating fingers312mutually adjacent in a vertical direction perpendicular to the direction in which paper100for image formation is transported comprise a single shaft531alinking the two paper-separating fingers312such that they respectively rotate as a unit, and support regions531brotatably supporting either end of this shaft531aat the tip regions thereof.

As a result, the single shaft531alinking, at support components531, the two paper-separating fingers312in each set of two mutually adjacent paper-separating fingers312causes operations bringing the finger bodies313of the paper-separating fingers312into and out of abutting engagement with the photosensitive body310bto be carried out in mutual cooperation, and, when small-size paper100for image formation is transported therethrough, operations causing engagement and/or retraction of the paper-separating fingers312corresponding to region S occupied by small-size paper100for image formation as it is transported therethrough are simultaneously accompanied by operations causing engagement and/or retraction of the paper-separating fingers312in region O not occupied by (i.e., outside of the path of) small-size paper100for image formation as it is transported therethrough, not only making it possible to effectively suppress scratching of the photosensitive body310band/or progress of unnecessary deterioration in region(s) of the photosensitive body310bnot occupied by (i.e., outside of the path of) the paper, but also making it possible to cause engagement and/or retraction operations in which the two paper-separating fingers312,312in each set of two paper-separating fingers312,312cooperate to be carried out smoothly and through employment of an extremely simple constitution.

Moreover, note that whereas, in the foregoing third embodiment, the two paper-separating fingers312in each set of paper-separating fingers312carried out engagement and/or retraction operations in mutual cooperation, it is alternatively possible, as indicated by the imaginary line (double-dash chain line) inFIG. 10, to employ a single shaft531a′ linking, at the support components531, all four paper-separating fingers312, . . . so as to cause operations bringing finger bodies313of the four paper-separating fingers312, . . . into and out of abutting engagement with the photosensitive body310bto be carried out in mutual cooperation.

Fourth Embodiment

Next, referring toFIG. 11, a fourth embodiment of the present invention is described.

In the present embodiment, specific limitation is made with respect to material(s) of the paper-separating finger(s) and the support member(s) beneath the cleaning apparatus(es). Note that in other respects the constitution, including that of the support member(s) and the paper-separating finger(s), is identical to that of the foregoing first embodiment, and like components will be assigned like reference numerals and detailed description thereof will be omitted.

To wit, as shown inFIG. 11, the present embodiment is provided with electrostatic clinging prevention means601preventing electrostatic clinging between the paper-separating finger(s)312and the support member(s)300beneath the cleaning apparatus310e, this or these support member(s)300being member(s) coming in contact with such paper-separating finger(s)312, during operations bringing the finger body or bodies313of the paper-separating finger(s)312into and out of abutting engagement with the photosensitive body310b. This electrostatic clinging prevention means601is the fact that the support member(s)300is or are formed from antistatic material(s); e.g., Excelloy EK10 available from TechnoPolymer Co., Ltd.

The surface resistivity or resistivities of such support member(s)300(antistatic material(s)) is set so as to be 3×1011Ω. More specifically, as shown in TABLE 1, below, it is clear that regardless of what material(s) is or are used for the support member(s), the surface resistivity or resistivities of the support member(s)300(antistatic material(s)) should be set so as to be not more than 1013Ω in order to prevent occurrence of electrostatic clinging between the paper-separating finger(s)312and the support member(s)300.

Here, when the paper-separating finger(s)312is or are not formed from antistatic material(s), as paper100for image formation, charged due to transfer of toner image(s) from the photosensitive body310bto paper100for image formation, passes near the finger body or bodies313of the paper-separating finger(s)312, such finger body or bodies313itself or themselves (paper-separating finger(s)312) become charged; and were charge allowed to accumulate due to charging of the paper-separating finger(s)312, electrostatic clinging would occur (i.e., the situation shown inFIG. 11) at location(s) C at which the paper-separating finger(s)312come in contact with the support member(s)300beneath the cleaning apparatus310e, and since the finger body or bodies313will still not contact the photosensitive body310beven after paper100for image formation has passed therethrough, transport thereto of a subsequent sheet of paper100for image formation while the paper-separating finger(s)312is or are still in this state will, as tip(s) of the finger body or bodies313of the paper-separating finger(s)312is or are located in the transport path of paper100for image formation and interfere with passage therethrough of paper100for image formation, result in a situation likely to cause occurrence of a jam when paper100for image formation slips underneath the finger body or bodies313.

Accordingly, in the present embodiment, the electrostatic clinging prevention means601—i.e., the fact that the support member(s)300beneath the cleaning apparatus310e, such support member(s)300coming in contact with the paper-separating finger(s)312during operations bringing the finger body or bodies313of the paper-separating finger(s)312into and out of abutting engagement with the photosensitive body310b, is or are formed from the antistatic material(s)—makes it possible to prevent occurrence of electrostatic clinging between the paper-separating finger(s)312and the support member(s)300, permitting operations bringing the finger body or bodies313of the paper-separating finger(s)312into and out of abutting engagement with the photosensitive body310bto be carried out in stable fashion, and permitting attainment of more assured tendency for paper100for image formation to separate from the photosensitive body310bas a result of action of the paper-separating finger(s)312.

Note that whereas, in the foregoing fourth embodiment, Excelloy EK10 (surface resistance 3×1011Ω) available from TechnoPolymer Co., Ltd., was employed as the antistatic material(s), Duracon ES5 (surface resistivity 5×102Ω; volume resistance 1×102Ω cm) available from Polyplastics Co., Ltd., may alternatively or in addition be employed as the antistatic material(s), in which case similar action and effect may be obtained.

Furthermore, whereas in the foregoing fourth embodiment the support member(s)300were formed from the antistatic material(s), the electrostatic clinging prevention means may alternatively or in addition consist of the fact that surface(s) of the support member(s) is or are coated with antistatic agent(s); e.g., Ohmirex [Phonetic transliteration of word in Japanese text.—Translator] #9-1 available from Omi Gijutsu Kenkyusho [Phonetic transliteration of word in Japanese text.—Translator], in which case similar action and effect may be obtained. Alternatively or in addition thereto, as shown inFIG. 12, the electrostatic clinging prevention means601may consist of the fact that charge-removing brush(es)600(charge-removing member(s)) is or are attached in the vicinity or vicinities of region(s) C at which the paper-separating finger(s)312contact the support member(s)300which come in contact with such paper-separating finger(s)312; in which case, contact with the charge-removing brush(es)600and consequent discharge in air permits removal of charge which has accumulated at the paper-separating finger(s)312, making it possible to prevent occurrence of electrostatic clinging between the paper-separating finger(s)312and the support member(s)300.

Moreover, whereas, in the foregoing embodiments, star-ring-type spur(s)314a(523) were employed as the guide member(s)314, there is no particular limitation with respect thereto, it being sufficient that shape(s) of component(s) making contact with paper for image formation in transport path(s) after the paper for image formation has separated from the photosensitive body or bodies be suitable for guiding the same (i.e., guide member(s)314may for example be arcuate, etc.).

The present invention may be embodied in a wide variety of forms other than those presented herein without departing from the spirit or essential characteristics thereof. The foregoing embodiments and working examples, therefore, are in all respects merely illustrative and are not to be construed in limiting fashion. The scope of the present invention being as indicated by the claims, it is not to be constrained in any way whatsoever by the body of the specification. All modifications and changes within the range of equivalents of the claims are moreover within the scope of the present invention.

Moreover, the present application claims right of benefit of prior filing dates of Japanese Patent Application No. 2002-314607 and Japanese Patent Application No. 2003-307027, the content of both of which is incorporated herein by reference in its entirety. Furthermore, all references cited in the present specification are specifically incorporated herein by reference in their entirety.