JP2006065271A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely avoid the occurrence of paper jamming, which cannot be dissolved by user, even if paper is adhered slantedly to an image carrier with respect to the paper transport direction. <P>SOLUTION: A printer 1 includes a transfer roller 31 for transferring a toner image on the surface of a photoreceptor drum 21 to the paper P, and a separation member 70 for separating the paper P adhered to the photoreceptor drum 21, in the middle portion with a cleaning roller 61 for cleaning the surface of the photoreceptor drum 21. The separation member 70 has a plurality of claws 71 that comes into contact with the photoreceptor drum 21. An interval X between adjacent claws 71 and a rotating direction distance Y, from the tip of the pawls 71 on the surface of the photoreceptor 21 to the contact part of the cleaning roller 61, has the relation X<2Y. Consequently, the paper P will be caught on each claw 71, even if entered between adjacent claws 71, and the tip of the paper P will not reach the contact part between the photoreceptor drum 21 and the cleaning roller 61. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus represented by a copying machine or a printer.

  In an electrophotographic image forming apparatus, a photosensitive drum, which is an image carrier, and a transfer roller, which is a transfer member, are brought into contact with or close to each other to form a transfer region. A transfer method for transferring a toner image formed on the drum surface onto a sheet is widely used.

  In such a transfer method, a small amount of toner may remain on the surface of the photosensitive drum without being transferred onto the paper after the toner image is transferred onto the paper. Since the residual toner on the surface of the photosensitive drum becomes an obstacle to the next new image formation, it needs to be cleaned. As cleaning methods used for such purposes, a cleaning roller as a cleaning member is pressed against the surface of the photosensitive drum to move the residual toner to the roller and collect it, or a cleaning blade is applied to the surface of the photosensitive drum. A method for removing residual toner by contact is widely known.

On the other hand, the paper on which the toner image has been transferred in the transfer nip portion may be in close contact with the surface of the image carrier due to electrostatic adsorption or the contact pressure between the photosensitive drum and the transfer roller. Such a sheet is usually separated from the surface of the photosensitive drum by the curvature of the photosensitive drum or the charge eliminating action by a separation needle to which a predetermined voltage is applied. However, even when such a separation method is used, when a sheet that is relatively close to contact, such as a relatively thin sheet, is used, the sheet may not be separated from the photosensitive drum. In view of this, an image forming apparatus has been proposed that includes a separation member that contacts the photosensitive drum on the downstream side of the transfer region in the sheet conveyance direction, and that peels off the sheet that is in close contact with the photosensitive drum. An example of such an image forming apparatus can be seen in Patent Document 1.
JP 2001-209251 A (page 4-5, FIG. 1-2)

  In the electrophotographic apparatus (image forming apparatus) described in Japanese Patent Application Laid-Open No. H10-228707, the recording medium winding is devised for its shape and operation only in consideration of easily separating the paper that is in close contact with the photosensitive drum. A prevention claw (separating member) is proposed, and it is effective if the edge of the leading edge of the sheet is kept parallel to the axis of the photosensitive drum. However, no special measures have been taken with respect to the case where the sheet is inclined with respect to the sheet conveyance direction and is in close contact with the photosensitive drum.

  When the sheet is slanted with respect to the sheet conveyance direction and is in close contact with the photosensitive drum, even if a plurality of wrapping prevention claws are arranged at intervals in the axial direction of the photosensitive drum, the arrangement method is special. If care is not taken, the corner of the leading edge of the paper may enter deeply into the downstream side of the photosensitive drum in the rotation direction from the gap between adjacent claws. As a result, the paper reaches and gets entangled with the cleaning unit provided on the downstream side in the rotation direction from the transfer region, and a paper jam that cannot be resolved by the user occurs. Therefore, in the case of using a separation member provided with a claw, it is necessary to take into account that the sheet is inclined with respect to the sheet conveyance direction and is in close contact with the photosensitive drum.

  In addition, the paper separated from the surface of the photosensitive drum needs to be conveyed promptly toward the fixing device on the downstream side of the photosensitive drum so that the paper jams around the separating member and does not stay. Therefore, there is a demand for a technique for skillfully separating the paper from the surface of the photosensitive drum and smoothly transporting the separated paper to the downstream side.

  The present invention has been made in view of the above points, and even when the sheet is inclined with respect to the sheet conveyance direction and is in close contact with the image carrier, it is possible to reliably generate a sheet jam that cannot be resolved by the user. It is an object of the present invention to provide an image forming apparatus that can avoid the problem and smoothly convey the paper separated from the surface of the image carrier.

  In order to solve the above problems, the present invention provides an image carrier that forms a toner image, a transfer member that transfers the toner image formed on the image carrier to paper, and a toner that remains on the surface of the image carrier. In the image forming apparatus including a cleaning member for cleaning, a separation member that separates a sheet that is in close contact with the image carrier from the image carrier is provided at an intermediate portion between the transfer member and the cleaning member. The front end includes a claw that contacts or approaches the image carrier, and at least two claws are arranged at intervals in the axial direction of the image carrier, and the distance X between adjacent claws and the surface of the image carrier The distance Y in the rotation direction of the image carrier from the position corresponding to the tip of the nail to the contact portion between the image carrier and the cleaning member has a relationship of X <2Y.

  Further, at least two or more of the separation members are configured as a single unit.

  In addition, the separation member includes a convex portion that protrudes toward a sheet conveyance space in which a sheet separated from the surface of the image carrier is conveyed.

  The convex portion is formed by cutting and bending.

  In addition, a protrusion is provided at an attachment location of the separation member, and the convex portion is formed by being bent by the protrusion when the separation member is attached.

  The separation member can be attached with an adhesive tape.

  Further, the separation member is detachable.

  Further, the cleaning member is constituted by a roller.

  The rotation direction of the roller with respect to the rotation axis is opposite to the rotation direction of the image carrier.

  According to the configuration of the present invention, the separation member that separates the sheet from the image carrier is provided at the intermediate portion between the transfer member and the cleaning member, and the separation member has a claw that is in contact with or close to the image carrier. And at least two claws arranged at intervals in the axial direction of the image carrier. From the position corresponding to the distance X between adjacent claws and the tip of the nail on the surface of the image carrier, the image carrier Since the distance Y in the rotation direction of the image carrier to the contact portion with the cleaning member has a relationship of X <2Y, the sheet is most inclined with respect to the sheet conveyance direction, that is, 45. Even if it is in close contact with the image carrier in an inclined state and enters between two adjacent separating members, it is caught by the claws of the two separating members, and the corner of the leading edge of the sheet is separated from the image carrier. In contact with the cleaning member Not be reached in. Therefore, it is possible to reliably avoid a paper jam that cannot be resolved by the user, that is, the paper becomes entangled in the cleaning unit.

  Since at least two or more of the separation members are integrally formed, a plurality of nails set at a predetermined interval in advance are obtained, and the image forming apparatus is adjusted one by one while adjusting the interval. There is no need to provide it. Therefore, it is possible to easily provide the image forming apparatus with a separation member that can prevent the sheet from reaching the cleaning unit.

  In addition, since the separating member has a convex portion that protrudes toward the paper conveyance space where the paper separated from the surface of the image carrier is conveyed, the paper comes into contact with the convex portion, and the leading edge of the paper carries the image carrying It points to the fixing device on the downstream side of the body. As a result, the sheet separated from the surface of the image carrier can be smoothly conveyed to the fixing device. Further, immediately after the sheet is separated from the surface of the image carrier by the separating member, the sheet contacts only with the convex portion, so that the entire surface of the sheet can be prevented from being stained with toner.

  Further, since the convex portion is formed by cutting and bending, the convex portion can be easily formed by bending. Accordingly, it is possible to smoothly convey the paper separated from the surface of the image carrier to the fixing device with a simpler configuration.

  In addition, since the projection is provided at the attachment position of the separation member and the convex portion is formed by being bent by the projection when the separation member is attached, the projection is automatically projected by attaching the separation member to the image forming apparatus. The part can be formed. Therefore, the convex portion that enables the paper separated from the surface of the image carrier to be smoothly conveyed does not need to be formed in advance on the separation member, and can be easily formed when the separation member is attached.

  In addition, since the separation member can be attached with an adhesive tape, a fixing member such as a screw is unnecessary, and the separation member can be attached at an arbitrary place. Accordingly, it is possible to limit a place where the separation member is attached in accordance with various paper sizes, or to newly add a separation member to an existing image forming apparatus. Therefore, the number of types of image forming apparatuses that can reliably avoid paper jam that cannot be resolved by the user increases, which is very convenient.

  In addition, since the separation member is detachable, the position of the separation member can be easily changed. As a result, the position of the separating member can be finely adjusted, so that paper jam that cannot be resolved by the user can be reliably avoided, and the performance of smoothly transporting the paper separated from the surface of the image carrier can be further improved. It becomes possible.

  The cleaning member is composed of a roller. When the cleaning roller is used as the cleaning member, when the paper reaches the cleaning unit, the paper is wound around the cleaning roller. As a result, the possibility of a paper jam that cannot be resolved by the user increases. Therefore, even when the cleaning roller is used, the image forming apparatus according to the present invention can prevent the paper from being wrapped around the paper and causing a paper jam that cannot be resolved by the user.

  Further, the rotation direction of the roller with respect to the rotation axis is opposite to the rotation direction of the image carrier. When the cleaning roller rotates in the direction opposite to the rotation direction of the image carrier, the movement direction on the circumferential surface is the same at the location where they are close to each other, and the paper enters the nip portion between the image carrier and the cleaning roller. easy. As a result, since the paper is easily wound around the cleaning roller, the possibility of a paper jam that cannot be resolved by the user is further increased. Even in such a case, the image forming apparatus of the present invention can prevent the paper from being wound around the cleaning roller and causing a paper jam that cannot be resolved by the user.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an outline of the structure of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper cassette 3 that is a paper storage unit is disposed below the inside of the main body 2 of the printer 1. Inside the paper cassette 3, paper P is stacked and stored. A paper feeding device 4 is disposed above the downstream portion of the paper cassette 3 in the paper conveyance direction. The sheet feeding device 4 feeds the sheet P toward the upper right of the sheet cassette 3 in FIG. The paper cassette 3 can be pulled out horizontally from the front side of the main body 2, that is, from the right side in FIG.

  A paper transport path 5, a registration roller 6, an image forming unit 20, and a transfer unit 30 are disposed downstream of the paper feed cassette 3 in the paper transport direction. The image forming unit 20 is provided with a photosensitive drum 21 as an image carrier at the center thereof. An optical unit 7 is provided above the image forming unit 20, and a laser beam L is emitted from the optical unit 7 toward the photosensitive drum 21. A one-dot chain line in the figure indicates the laser beam L. The transfer unit 30 includes a transfer roller 31 that is a transfer member. The transfer roller 31 is pressed against the photosensitive drum 21 from below, and forms a transfer nip portion that is a transfer region for transferring the toner image onto the paper P.

  A fixing unit 8, a sheet conveyance path 9, and a sheet discharge unit 10 are disposed downstream of the image forming unit 20 and the transfer unit 30 in the sheet conveyance direction. The paper discharge unit 10 is provided on the upper surface of the main body 2 at a position where the printed paper P can be taken out from the outside.

  The printer 1 having the above configuration performs a printing operation as follows.

  The paper P before printing is stored in the paper cassette 3 in a stacked state, and is separated and sent out one by one by the paper feeding device 4 from here. The fed paper P reaches the registration roller 6 through the paper conveyance path 5. The registration roller 6 feeds the paper P to the transfer unit 30 by correcting the oblique feeding of the paper P and timings the toner image formed by the image forming unit 20.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and laser light L controlled by the optical unit 7 is irradiated based on the image data. As a result, an electrostatic latent image of a document image is formed on the photosensitive drum 21 in the image forming unit 20, and a toner image is formed on the photosensitive drum 21 from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 6 at a transfer nip portion formed by press contact between the photosensitive drum 21 and the transfer roller 31 of the transfer portion 30.

  Thereafter, the paper P carrying the unfixed toner image is sent to the fixing unit 8 where the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 8 is sent upward through the paper conveyance path 9 and is discharged out of the apparatus from a paper discharge unit 10 provided on the upper surface of the main body 2.

  Next, a detailed configuration around the image forming unit 20 of the printer 1 according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 5 in addition to FIG. FIG. 2 is a schematic vertical sectional partial enlarged view showing the periphery of the image forming unit. 3 is a partial perspective view showing a separation member of the image forming unit in FIG. 2, FIG. 4 is a schematic partially enlarged bottom view showing a photosensitive drum and a cleaning device of the image forming unit in FIG. 2, and FIG. 5 is a separation of FIG. It is a model partial enlarged view which shows the relationship between a member and the paper adjacent to this.

  As shown in FIG. 2, the image forming unit 20 includes a photosensitive drum 21 as an image carrier at the center thereof. A main charging device 40, a developing device 50, and a cleaning device 60 as a cleaning unit are arranged in order along the rotation direction of the photosensitive drum 21. The transfer unit 30 is provided between the developing device 50 and the cleaning device 60 along the rotation direction of the photosensitive drum 21.

  The photoconductor drum 21 is an inorganic photoconductor in which amorphous silicon, which is an inorganic photoconductive material, is provided on the outside of a conductive roller-shaped substrate made of aluminum or the like by vacuum deposition or the like. The photosensitive drum 11 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the paper conveyance speed.

  The main charging device 40 is a scorotron charging device using a corona discharge charger. Similarly, a corotron charging device using a corona discharge charger or a contact charging device using a roller or a brush may be used. The main charging device 40 uniformly charges the surface of the photosensitive drum 21 with a predetermined polarity and potential.

  The developing device 50 is provided with a developing roller 51 that contacts the photosensitive drum 21. A bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied to the developing roller 51. The developing roller 51 charges the toner, which is a developer, and supplies the toner to the surface of the photosensitive drum 21 to develop the electrostatic latent image. As shown in FIG. 1, a toner supply container 52 for supplementing toner to the developing device 50 is provided above the developing device 50, and the toner is replenished by a conveying means (not shown). As the toner, a magnetic or non-magnetic one-component toner or a two-component toner obtained by mixing a magnetic carrier and an insulating toner is used. Further, in order to clean the surface of the photosensitive drum 21 by polishing, a small amount of powder of titanium oxide, alumina or the like may be mixed into the toner as an abrasive.

  The transfer unit 30 is provided with a transfer roller 31 as a transfer member. The transfer roller 31 includes a cored bar and a conductive elastic layer provided outside the cored bar. The conductive elastic layer is made of polyurethane rubber or the like in which a conductive material such as carbon is dispersed. The transfer roller 31 is in pressure contact with the photosensitive drum 21 to form a transfer nip portion through which the paper P is inserted. The transfer roller 31 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the peripheral speed of the photosensitive drum 21. Further, a transfer bias is applied to the transfer roller 31 as necessary. In FIG. 2, the conveyance path of the paper P is indicated by a two-dot chain line.

  The cleaning device 60 is disposed further downstream of the transfer nip portion along the rotation direction of the photosensitive drum 21. The cleaning device 60 includes a cleaning roller 61 that is a cleaning member, and a housing 62.

  The cleaning roller 61 is provided in contact with the photosensitive drum 21. The cleaning roller 61 has substantially the same length in the axial direction as the photosensitive drum 21, is urged by an elastic member such as a spring (not shown), and is pressed against the photosensitive drum 21. And in order to carry out cleaning efficiently, it is necessary to relatively move the peripheral surfaces of each other. Therefore, the cleaning roller 61 is rotated in a direction opposite to the rotation direction of the photosensitive drum 21 with respect to the rotation axis so that the peripheral speed of the cleaning roller 61 is about 15 to 20% higher than the peripheral speed of the photosensitive drum 21 by a driving device (not shown). Has been rotated. The cleaning roller 61 removes the toner remaining on the surface of the photosensitive drum 21 and cleans it. The toner removed from the surface of the photosensitive drum 21 is collected in the housing 62.

  A separation member 70 is provided on the lower surface of the housing 62 of the cleaning device 60. As shown in FIG. 3, the separating member 70 is in the form of a film made of polyethylene terephthalate (PET), and is detachably attached with an adhesive tape such as a double-sided tape. The separating member 70 includes a plurality of claws 71 protruding upstream in the paper conveyance direction, and has substantially the same axial length as the photosensitive drum 21. In addition, a plurality of separation members having a single claw may be arranged in an integrated manner in the axial direction of the photosensitive drum 21. The claw 71 has a triangular shape, a protruding length of 3 mm, and a tip angle of 30 °. The tip of the claw 71 is in light contact with the surface of the photosensitive drum 21. The predetermined interval provided between the adjacent claws 71 is as follows.

  First, as shown in FIGS. 4 and 5, let X be the interval between adjacent claws 71 in the separating member 70. Next, as shown in FIGS. 2 and 4, in the photosensitive drum 21, the position in the rotation direction corresponding to the tip of the claw 71 on the surface is point A, and the position in the rotation direction of the contact portion with the cleaning roller 61. Is a point B, and the rotational distance of the photosensitive drum 21 between these two points is Y. Here, the predetermined interval provided between the adjacent claws 71 of the separating member 70 is an interval when the claws 71 are arranged so that the relationship X <2Y is established.

  The image forming unit 20 and the transfer unit 30 configured as described above perform an image forming operation as follows.

  First, the main charging device 40 uniformly charges the surface of the photosensitive drum 21 with a predetermined polarity and potential. The charging potential at this time is usually about 200 to 1000V. Then, the photosensitive drum 21 is irradiated with a laser beam L controlled based on image data read by the optical unit 7 (see FIG. 1), and the potential of the irradiated portion is attenuated so that the electrostatic latent image of the document image. Is made. The toner charged by the developing device 50 is supplied to the surface of the photosensitive drum 21 by the developing roller 51, and a toner image is formed from the electrostatic latent image.

  On the other hand, the sheet P is synchronized with the toner image formation on the surface of the photosensitive drum 21 by the registration roller 6 (see FIG. 1), and is formed in a transfer nip portion formed by press-contacting the photosensitive drum 21 and the transfer roller 31. It is inserted. At this time, a negative transfer bias having a polarity opposite to that of the photosensitive drum 21 and the toner is applied to the transfer roller 31. As a result, the toner moves from the photosensitive drum 21 to the transfer roller 31, and the toner image is contact-transferred onto the paper P.

  After the toner image is transferred, the toner remaining on the photosensitive drum 21 moves to the cleaning roller 61 provided in the cleaning device 60, and the toner is collected in the housing 62. At this time, a part of the toner remains on the cleaning roller 61 and is not collected, and the surface of the photosensitive drum 21 is polished by this toner.

  The sheet P onto which the toner image has been transferred is usually separated from the photosensitive drum 21 due to the curvature of the photosensitive drum 21 on the downstream side of the transfer nip portion, as indicated by a two-dot chain line shown in FIG. Oriented to the fixing unit 8. However, when the paper P cannot be separated from the photosensitive drum 21, the paper P is caught by the separation member 70 as shown in FIG. FIG. 5 illustrates a state in which the sheet P is in close contact with the photosensitive drum 21 at an angle of 45 ° with respect to the sheet conveyance direction.

  Here, in FIG. 5, the length from the tip of the claw 71 to the tip of the paper P that has entered between the adjacent claws 71 is defined as Z. At this time, since the corner portion of the sheet P is 90 °, the interval X between the adjacent claws 71 and the entry length Z of the sheet P have a relationship of X = 2Z. On the other hand, as described above, the distance X between the adjacent claws 71 and the rotational distance Y between the claw 71 and the cleaning roller 61 on the surface of the photosensitive drum 21 have a relationship of X <2Y. As a result, the entering length Z of the paper P and the rotational direction distance Y between the claw 71 and the cleaning roller 61 are in a relationship of Z <Y. Therefore, the leading edge of the sheet P that has entered the cleaning roller 61 from between the adjacent claws 71 does not reach the contact portion between the photosensitive drum 21 and the cleaning roller 61. Eventually, the paper P is peeled off from the surface of the photosensitive drum 21 by the separating member 70 and sent to the downstream side.

  In this way, the separation member 70 that separates the paper P from the photosensitive drum 21 that is the image carrier is provided at the intermediate portion between the transfer roller 31 that is the transfer member and the cleaning roller 61 that is the cleaning member. 70 includes a claw 71 whose tip is in contact with the photosensitive drum 21, and at least two claws 71 are arranged at intervals in the axial direction of the photosensitive drum 21, and an interval X between adjacent claws 71; The distance Y in the rotational direction of the photosensitive drum 21 from the position corresponding to the tip of the claw 71 on the surface of the photosensitive drum 21 to the contact portion between the photosensitive drum 21 and the cleaning roller 61 has a relationship of X <2Y. Therefore, the sheet P is in close contact with the photosensitive drum 21 in a state where the sheet P is inclined most with respect to the sheet conveyance direction, that is, in a state where the sheet P is inclined by 45 °. Even enters between the 71, caught on each of the pawls 71, no corners of the leading edge of the sheet reaches the contact portion between the photosensitive drum 21 and the cleaning roller 61. Therefore, it is possible to reliably avoid the paper jam that the paper P is entangled with the cleaning device 60 as the cleaning unit and cannot be solved by the user.

For example, when the maximum usable paper of the printer 1 is A4 size (conveyed in the longitudinal direction), if a thin paper (50 g / m ² ) whose size is smaller than a postcard is used, the paper P becomes slanted. In this state, the contact with the photosensitive drum 21 is facilitated. However, even if such a problem occurs, the above-described configuration of the present invention can reliably avoid a paper jam that cannot be resolved by the user, such as the paper P entangled with the cleaning device 60.

  Since the separation member 70 may be formed by integrating at least two separation members, a plurality of claws 71 set in advance at a predetermined interval are obtained, one by one while adjusting the interval. There is no need to provide the printer 1. Therefore, it is possible to easily provide the printer 1 with the separation member 70 that can prevent the paper P from reaching the cleaning device 60.

  Moreover, in the said embodiment, the cleaning member is comprised with the roller. When the cleaning roller 61 is used as the cleaning member, when the paper P reaches the cleaning device 60, the paper P is wrapped around the cleaning roller 61. As a result, the possibility of a paper jam that cannot be resolved by the user increases. Therefore, even if the cleaning roller 61 is used as the cleaning member, the above-described configuration of the present invention can prevent the paper P from being wrapped around the paper jam that cannot be resolved by the user. It is.

  Further, in the above embodiment, the rotation direction of the cleaning roller 61 with respect to the rotation axis is opposite to the rotation direction of the photosensitive drum 21. When the cleaning roller 61 rotates in the direction opposite to the rotation direction of the photosensitive drum 21, the moving direction on the peripheral surface is the same at the location where the two are close to each other, and the nip portion between the photosensitive drum 21 and the cleaning roller 61 is the same. The paper P is easy to enter. As a result, since the paper P is easily wound around the cleaning roller 61, the possibility of a paper jam that cannot be resolved by the user is further increased. Even in such a case, with the above-described configuration of the present invention, it is possible to prevent the paper P from being wrapped around the cleaning roller 61 and becoming a paper jam that cannot be resolved by the user.

  Moreover, since the separating member 70 can be attached with an adhesive tape, a fixing member such as a screw is not necessary, and the separating member 70 can be attached at an arbitrary place. Accordingly, it is possible to limit a place where the separation member 70 is attached corresponding to various paper sizes, or to newly add the separation member 70 to an existing image forming apparatus. Therefore, the number of types of image forming apparatuses that can reliably avoid paper jam that cannot be resolved by the user increases, which is very convenient.

  Since the separating member 70 is detachable, the position of the separating member 70 can be easily changed. Thereby, since the position of the separating member 70 can be finely adjusted, the performance of reliably avoiding a paper jam that cannot be resolved by the user or smoothly transporting the paper P separated from the surface of the photosensitive drum 21 is further improved. It becomes possible to make it.

  Next, the detailed configuration of the separating member of the printer according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a partial perspective view illustrating a separation member of the image forming unit. Since the basic configuration of this embodiment is the same as that of the first embodiment, the description of the drawings and the description of the components common to the first embodiment will be omitted.

  As in the first embodiment, the separation member 80 according to the second embodiment is provided on the lower surface of the housing 62 (see FIG. 2) of the cleaning device 60. A plurality of separation members 80 are arranged side by side in the axial direction of the photosensitive drum 21 indicated by a two-dot chain line in FIG. Each separation member 80 is molded from a synthetic resin, and a base portion 81 is provided with a claw 82, a rotating shaft 83, and a spring mounting portion 84. The tip of the claw 82 faces the upstream side in the paper transport direction. The separation member 80 is supported by a support portion (not shown) provided on the lower surface of the housing 62, and the rotation shaft 83 is supported. The separation member 80 can rotate within a vertical plane. The spring mounting portion 84 is positioned above the rotation shaft 83, and a spring 85 is connected between the spring mounting portion 84 and a spring mounting portion (not shown) provided on the lower surface of the housing 62. Due to the positional relationship between the rotary shaft 83 and the spring mounting portion 84 and the action of the spring 85, the tip of the claw 82 is urged upward and is in contact with the surface of the photosensitive drum 21. The spring force of the spring 85 is a spring force that does not damage the surface of the photosensitive drum 21 at the tip of the claw 82.

  A plurality of separation members 80 having such a single claw 82 are arranged side by side in the axial direction of the photosensitive drum 21 as described above. When the interval between the claws 81 of the adjacent separating members 80 is X, the rotational direction distance Y between the claw 81 and the cleaning roller 61 on the surface of the photosensitive drum 21 is X <2Y as in the first embodiment. Have the relationship Accordingly, even in the case of the separation member 80 having a single claw 82 as in this embodiment, the interval between the claws 81 of the adjacent separation members 80 is set to a predetermined interval, so that the first embodiment It is possible to obtain the same operation and effect as the above.

  Next, the detailed configuration of the separating member of the printer according to the third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a partially enlarged schematic vertical section showing the periphery of the image forming unit. FIG. 8 is a partial perspective view showing the separation member of the image forming unit of FIG. 7, and FIG. 9 is a partial perspective view similar to FIG. 8, showing the separation member before attachment and its attachment location. Since the basic configuration of this embodiment is the same as that of the first embodiment, the description of the drawings and the description of the components common to the first embodiment will be omitted.

  As shown in FIG. 7, the separation member 70 according to the third embodiment is provided on the lower surface of the housing 62 of the cleaning device 60 as in the first embodiment. As shown in FIG. 8, the separating member 70 includes a plurality of convex portions 72 at the base portion. The convex portion 72 protrudes toward the paper conveyance space where the paper P separated from the surface of the photosensitive drum 21 is conveyed (see FIG. 7). The convex portion 72 is formed by cutting and bending the base portion of the separating member 70 that forms the film shape.

  Then, the formation method of this convex part 72 is demonstrated. Here, in FIG. 9, the separating member 70 before the convex portion 72 is formed is drawn. As described above, the convex portion 72 is formed as “cut and raised” on the film-like base portion of the separation member 70.

  On the other hand, a protrusion 90 is provided on the lower surface of the housing 62 of the cleaning device 60 so as to protrude toward the sheet conveyance space. The number of the protrusions 90 is the same as that of the plurality of protrusions 72 provided on the separation member 70, and each of the protrusions 90 is disposed at a position corresponding to the protrusion 72. The protrusion height of the protrusion 90 into the sheet conveyance space is lower than that of the protrusion 72 of the separating member 70. Therefore, the paper P contacts only the convex portion 72 and does not contact the protrusion 90.

  When the separation member 70 is brought close to the lower surface of the housing 62 of the cleaning device 60 provided with such a projection 90 as shown in FIG. 9, the projection 90 is still in a flat state. 72 points are touched. Then, by continuously pressing the separating member 70 toward the housing 62, the protrusion 72 of the separating member 70 is formed by being bent by the protrusion 90 as shown in FIG. 8.

  As described above, the separating member 70 includes the convex portion 72 that protrudes toward the paper conveyance space where the paper P separated from the surface of the photosensitive drum 21 that is an image carrier is conveyed. 72, the leading edge of the paper P is directed to the fixing device 8 on the downstream side of the photosensitive drum 21. As a result, the paper P separated from the surface of the photosensitive drum 21 can be smoothly conveyed to the fixing device 8. Further, immediately after the sheet P is separated from the surface of the photosensitive drum 21 by the separating member 70, the sheet P contacts only the convex portion 72, so that the entire sheet surface can be prevented from being stained with toner.

  Moreover, since the convex part 72 is formed by cutting up and bending, the convex part 72 can be easily formed by bending. Therefore, the paper P separated from the surface of the photosensitive drum 21 can be smoothly conveyed to the fixing device 8 with a simpler configuration.

  Further, the protrusion 90 is provided on the lower surface of the housing 62 of the cleaning device 60 where the separation member 70 is attached, and the protrusion 72 is formed by being bent by the protrusion 90 when the separation member 70 is attached. By attaching to the image forming apparatus 1, the convex portion 72 can be automatically formed. Therefore, the convex portion 72 that enables the paper P separated from the surface of the photosensitive drum 21 to be smoothly conveyed does not need to be formed in advance on the separation member 70 and is easily formed when the separation member 70 is attached. be able to.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in all image forming apparatuses that transfer a toner image onto a sheet by inserting the sheet into a transfer region formed in contact with or close to the image carrier and the transfer member.

It is a model vertical section left side view showing a printer concerning an embodiment of the present invention. FIG. 3 is a partially enlarged schematic vertical cross section showing the periphery of the image forming unit of the printer according to the first exemplary embodiment of the present invention. FIG. 3 is a partial perspective view illustrating a separation member of the image forming unit in FIG. 2. FIG. 3 is a schematic partial enlarged bottom view showing a photosensitive drum and a cleaning device of the image forming unit in FIG. 2. FIG. 5 is a schematic partial enlarged view showing a relationship between the separating member of FIG. 4 and a sheet adjacent to the separating member. It is a perspective view which shows the separating member of the image formation part of the printer which concerns on the 2nd Embodiment of this invention. It is a model vertical cross-section part enlarged view which shows the image formation part periphery of the printer which concerns on the 3rd Embodiment of this invention. FIG. 8 is a partial perspective view illustrating a separation member of the image forming unit in FIG. 7. FIG. 9 is a partial perspective view similar to FIG. 8 and shows the separation member before attachment and its attachment location.

Explanation of symbols

1 Printer (image forming device)
2 Main body 20 Image forming unit 21 Photosensitive drum (image carrier)
30 Transfer section 31 Transfer roller (transfer member)
60 Cleaning device (cleaning part)
61 Cleaning roller (cleaning member)
70, 80 Separating member 71, 82 Claw 72 Projection 90 Projection

Claims (9)

An image forming apparatus comprising: an image carrier that forms a toner image; a transfer member that transfers a toner image formed on the image carrier to a sheet; and a cleaning member that cleans toner remaining on the surface of the image carrier. ,
A separation member for separating the sheet in close contact with the image carrier from the image carrier is provided at an intermediate portion between the transfer member and the cleaning member, and the separation member has a nail whose tip is in contact with or close to the image carrier. And at least two claws arranged at intervals in the axial direction of the image carrier, and from the position corresponding to the distance X between adjacent claws and the tip of the nail on the surface of the image carrier. An image forming apparatus characterized in that the distance Y in the rotation direction of the image carrier to the contact portion between the cleaning member and the cleaning member has a relationship of X <2Y.   The image forming apparatus according to claim 1, wherein at least two of the separation members are integrally formed.   The image forming apparatus according to claim 1, wherein the separation member includes a convex portion that protrudes toward a paper conveyance space in which the paper separated from the surface of the image carrier is conveyed.   The image forming apparatus according to claim 3, wherein the convex portion is formed by cutting and bending.   The image forming apparatus according to claim 4, wherein a protrusion is provided at an attachment location of the separation member, and the convex portion is formed by being bent by the protrusion when the separation member is attached.   The image forming apparatus according to claim 1, wherein the separation member can be attached with an adhesive tape.   The image forming apparatus according to claim 1, wherein the separation member is detachable.   The image forming apparatus according to claim 1, wherein the cleaning member includes a roller.   9. The image forming apparatus according to claim 8, wherein a rotation direction of the roller with respect to the rotation axis is opposite to a rotation direction of the image carrier.

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