JP2016095361A - Charging device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging device that can reduce a friction force between an image carrier and a sealing member.SOLUTION: A charging device 15 of the present invention includes a charging roller 22 that is in contact with a rotating photoreceptor drum 14 to charge the photoreceptor drum 14 at the time of image formation, a case 21 that is provided to cover a contact part of the charging roller 22 and photoreceptor drum 14, and a sealing member 24 that is provided on the case 21 in an attitude to be in contact with the photoreceptor drum 14, where the sealing member 24 has a toner layer 50 formed on its surface by applying a toner in a range including a contact end part 24a of the sealing member 24 with respect to the photoreceptor drum 14, and the toner layer 50 is formed on the surface of the sealing member 24 before execution of the initial image formation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a charging device suitably used for a copying machine, a printer, and the like, and an image forming apparatus including the charging device.

  In recent years, an image forming apparatus using electrophotographic technology has a charging device that performs a charging process by bringing a charging member into contact with the surface of a photoconductor in order to suppress the generation of discharge products such as ozone and nitrogen oxides. I have. However, even the contact charging type charging device cannot completely stop the generation of the discharge product. When the discharge product adhered to the surface of the photoconductor, the surface resistance of the photoconductor decreased, and an appropriate electrostatic latent image could not be formed on the surface of the photoconductor (image flow phenomenon).

  In order to solve the above problems, various techniques have been proposed. For example, the charging device described in Patent Document 1 includes a conductive roller that is in contact with the surface of a photosensitive drum (image carrier) that is rotationally driven and a cover that is in contact with the surface of the photosensitive drum. The cover is provided with an elastic body (seal member) that comes into contact with the photosensitive drum. In this charging device, the discharge region between the conductive roller and the photosensitive drum is covered with a cover, thereby reducing the oxygen concentration in the discharge region and reducing the generation of discharge products.

JP-A-11-305522

  However, in the charging device described in Patent Document 1, the elastic body that slides relatively on the photosensitive drum sometimes vibrates violently due to frictional force. In this case, the vibration of the elastic body may propagate to the casing (apparatus main body) of the image forming apparatus and generate abnormal noise by causing the casing to resonate. In particular, a large frictional force is generated between the photosensitive drum and the elastic body when it is new. For this reason, the image forming apparatus provided with the above-described charging device has a problem that a large noise is generated when the image forming process is first executed.

  In order to solve the above-described problems, an object of the present invention is to provide a charging device in which the frictional force between an image carrier and a seal member is reduced, and an image forming apparatus including the charging device.

  To achieve the above object, the charging device of the present invention comprises a charging member that contacts a rotating image carrier and charges the image carrier during image formation, and a contact portion between the charging member and the image carrier. A case provided to cover the image carrier and a seal member provided to the case in a posture in contact with the image carrier, and a contact end portion of the seal member with respect to the image carrier on a surface of the seal member A toner layer is formed by applying toner to a range including the toner layer, and the toner layer is formed on the surface of the seal member before the first image formation is performed.

  According to this configuration, the seal member is in contact with the surface of the image carrier with the toner layer interposed therebetween. The toner layer serves as a lubricant and reduces the frictional force acting between the image carrier and the seal member. In addition, the first image forming process is executed with the toner layer formed on the seal member. Therefore, for example, even when the image carrier and the seal member are new with a large frictional resistance, the seal member can smoothly move relative to each other while being in contact with the surface of the image carrier. Thereby, since the vibration of the seal member due to the frictional force is suppressed, it is possible to prevent the generation of abnormal noise based on the vibration.

  In this case, it is preferable that the toner layer is formed at least on the surface of the seal member on the upstream side in the rotation direction of the image carrier.

  In this case, it is preferable that the toner layer is formed at least in a range up to a position 2 mm away from the contact end portion of the seal member.

  According to these configurations, the toner layer is formed at a position having the largest frictional resistance in the contact range between the image carrier and the seal member. Therefore, the toner layer can effectively reduce the frictional force between the image carrier and the seal member. Thereby, generation | occurrence | production of abnormal noise can be prevented effectively. The applicant of the present application has confirmed that a good noise prevention effect can be exhibited by providing a toner layer up to a position 2 mm away from the contact end of the seal member on the upstream side in the rotation direction of the image carrier. doing.

  In order to achieve the above object, an image forming apparatus of the present invention includes any of the above-described charging devices.

  According to this configuration, since the seal member is in contact with the image carrier with the toner layer serving as a lubricant interposed therebetween, the frictional force acting on the contact portion is reduced. In addition, the first image forming process is executed with the toner layer formed on the seal member. Accordingly, the relative sliding of the seal member with respect to the image carrier is smoothly performed. Thereby, since the vibration of the seal member due to the frictional force is suppressed, it is possible to prevent the generation of abnormal noise based on the vibration.

  In this case, a developing device that supplies toner to the image carrier that is rotationally driven while carrying an electrostatic latent image to develop the electrostatic latent image into a toner image, and at least rotational driving of the image carrier and the And a control device for controlling the developing operation of the developing device, wherein the control device rotates the image carrier in a direction opposite to that during image formation, and supplies the toner supplied from the developing device to the image carrier. It is preferable to execute toner application control for conveying the toner to the seal member to form the toner layer.

  According to this configuration, the toner layer is formed on the seal member simply by causing the control device to execute toner application control. Accordingly, the toner layer can be formed easily and quickly without changing the design or adding to the structure of the image forming apparatus or the charging device. Further, for example, the efficiency related to the toner layer forming operation can be dramatically improved as compared with the case where the operator accesses the inside of the image forming apparatus and manually applies the toner to the seal member. For example, even when the worn image carrier or seal member is replaced with a new one, the toner layer can be formed easily and quickly by executing the toner application control.

  According to the present invention, the frictional force between the image carrier and the seal member can be reduced. Further, vibration of the seal member due to the frictional force can be suppressed, and generation of abnormal noise based on the vibration can be prevented.

FIG. 2 is a cross-sectional view schematically showing the internal structure of the printer according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating an image forming unit of the printer according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a printer control device and the like according to the first embodiment of the present invention. It is sectional drawing which shows typically the charging device which concerns on 1st Embodiment of this invention. 3 is a flowchart of toner application control executed by the printer control apparatus according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating a charging device or the like according to the first embodiment of the present invention during toner application control. FIG. 3 is a cross-sectional view schematically illustrating a state where the toner layer is formed in the charging device or the like according to the first embodiment of the present invention. It is sectional drawing which shows typically the charging device which concerns on 2nd Embodiment of this invention, and the jig | tool which supports this.

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

  A printer 1 as an image forming apparatus according to the first embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a cross-sectional view schematically showing the internal structure of the printer 1. FIG. 2 is a cross-sectional view schematically showing the image forming unit 6 of the printer 1. FIG. 3 is a block diagram showing the control device 8 and the like of the printer 1. FIG. 4 is a cross-sectional view schematically showing the charging device 15. The following description is based on the directions indicated by the arrows in each drawing.

  As shown in FIG. 1, the printer 1 includes a substantially box-shaped apparatus main body 2, a paper feed cassette 3 provided at the lower part of the apparatus main body 2, and a paper discharge tray 4 provided at the upper part of the apparatus main body 2. I have. In addition, the printer 1 includes a paper feeding unit 5, an image forming unit 6, a fixing device 7, and a control device 8 inside the apparatus main body 2. The paper feed unit 5 is provided on the upstream side of the conveyance path 10 extending from the paper feed cassette 3 to the paper discharge tray 4. The image forming unit 6 is provided in an intermediate portion of the conveyance path 10. The fixing device 7 is provided on the downstream side of the conveyance path 10. The control device 8 is provided for overall control of each part.

  The paper feed unit 5 sends out the paper S stored in the paper feed cassette 3 to the transport path 10. The paper S stored in the paper feed cassette 3 is not limited to paper and may be a resin film, an OHP (Over Head Projector) sheet, or the like.

  The image forming unit 6 includes a toner container 11, a drum unit 12, and an optical scanning device 13. The toner container 11 contains a replenishing toner (black). The drum unit 12 transfers the toner image on the photosensitive drum 14 onto the paper S to form a monochrome image. The optical scanning device 13 emits scanning light and forms an electrostatic latent image on the surface of the photosensitive drum 14. The toner may be a one-component developer made of a magnetic toner or a two-component developer containing a toner and a carrier.

  The drum unit 12 includes a photosensitive drum 14, a charging device 15, a developing device 16, a transfer roller 17, and a cleaning device 18. The charging device 15, the developing device 16, the transfer roller 17 and the cleaning device 18 are arranged around the photosensitive drum 14 in the order of the transfer process.

  As shown in FIG. 2, the photosensitive drum 14 serving as an image carrier includes a drum tube 14a and a photosensitive layer 14b. The drum base tube 14a is formed in a cylindrical shape that is long in the front-rear direction (the depth direction in FIG. 2) using a conductive material (such as aluminum). The photosensitive layer 14b is coated on the outer peripheral surface of the drum base tube 14a. The photosensitive layer 14b is formed of a positively charged single-layer organic photoreceptor that is low in toxicity and excellent in mass productivity. The layer thickness of the photosensitive layer 14b is set to about 20 to 30 μm, for example.

  The photosensitive drum 14 (drum base tube 14a) is pivotally supported by a frame (not shown) in the apparatus main body 2. The photosensitive drum 14 is rotationally driven by a driving device 20 (see FIG. 3) while carrying an electrostatic latent image formed by exposure from the optical scanning device 13. In addition, although illustration is abbreviate | omitted, the drive device 20 is comprised including motive power transmission mechanisms, such as a drive motor and a gear train. The driving device 20 is driven by power from a power source (not shown).

  The charging device 15 includes a case 21, a charging roller 22, a brush roller 23, and a seal member 24.

  The case 21 has an opening 21a on the photosensitive drum 14 side, and is formed in a substantially rectangular box shape that is long in the front-rear direction. Inside the case 21, a charging roller 22 and a brush roller 23 are pivotally supported.

  The charging roller 22 as a charging member includes a charging shaft 22a and a charging rubber layer 22b. The charging shaft 22a is formed in a solid cylindrical shape that is long in the front-rear direction by a conductive material. The charging shaft 22 a is disposed in parallel with the photosensitive drum 14. The charging rubber layer 22b is laminated on the outer peripheral surface of the charging shaft 22a. The charged rubber layer 22b is formed of, for example, a conductive material in which an ionic conductive agent is mixed with epichlorohydrin rubber or the like. The layer thickness of the charged rubber layer 22b is set to about 1 to 3 mm, for example.

  The charging roller 22 is partially exposed from the opening 21 a of the case 21 and is in contact with the surface of the photosensitive drum 14. The charging roller 22 is rotationally driven around an axis by a driving device 20 (see FIG. 3). The charging roller 22 is connected to a charging bias power source 25 (see FIG. 3). The charging bias power supply 25 applies a charging bias (DC voltage) to the charging roller 22. As a result, the charging roller 22 contacts the rotating photosensitive drum 14 and charges the photosensitive drum 14 (photosensitive layer 14b) during image formation (charging operation).

  The brush roller 23 is disposed on the opposite side of the photosensitive drum 14 with the charging roller 22 interposed therebetween. The brush roller 23 is formed in a cylindrical shape that is long in the front-rear direction, and is in contact with the surface of the charging roller 22. The brush roller 23 is rotationally driven around the axis by the driving device 20 (see FIG. 3). Thereby, the brush roller 23 removes the deposits on the surface of the charging roller 22.

  A seal member 24 is provided on the side wall of the case 21 on the upstream side in the rotation direction of the photosensitive drum 14. The seal member 24 is formed in a substantially rectangular plate shape that is long in the front-rear direction by, for example, urethane resin. The proximal end portion of the seal member 24 is fixed to the side wall of the case 21, and the distal end portion of the seal member 24 is in contact with the surface of the photosensitive drum 14 with substantially uniform pressure. That is, the seal member 24 is disposed in parallel with the photosensitive drum 14 so as to close a gap between the photosensitive drum 14 and the case 21.

  The case 21 described above is provided so as to cover the contact portion (discharge region) between the charging roller 22 and the photosensitive drum 14. Further, the gap between the photosensitive drum 14 and the case 21 is closed by a seal member 24. Thereby, the oxygen concentration in the discharge region can be lowered, and the generation of discharge products can be reduced.

  As shown in FIG. 1, the developing device 16 includes a developing roller 31 that is pivotally supported inside the developing housing 30. The developing roller 31 is formed in a cylindrical shape that is long in the front-rear direction, and is disposed in parallel with the photosensitive drum 14. A part of the developing roller 31 is exposed from the developing housing 30, and a slight gap is formed between the developing roller 31 and the photosensitive drum 14. The toner container 11 is connected to the developing case 30 via a pipe or the like (not shown). As a result, toner is supplied from the toner container 11 into the developing housing 30. A pair of conveying screws 32 that circulate the toner while stirring are provided inside the developing housing 30. The developing roller 31 and the pair of conveying screws 32 are rotationally driven by the driving device 20 (see FIG. 3).

  The developing roller 31 is connected to a developing bias power source 33 (see FIG. 3). The development bias power source 33 applies a development bias in which an alternating voltage and a direct current voltage are superimposed to the development roller 31. As a result, the developing device 16 (developing roller 31) supplies toner to the photosensitive drum 14 and develops the electrostatic latent image on the photosensitive drum 14 into a toner image (developing operation).

  The transfer roller 17 is formed in a cylindrical shape that is long in the front-rear direction by a conductive material. The transfer roller 17 is provided to face the photosensitive drum 14 with the conveyance path 10 interposed therebetween. The transfer roller 17 is connected to a transfer bias power source 34 (see FIG. 3). The transfer bias power supply 34 applies a transfer bias having a polarity opposite to the polarity of the toner to the transfer roller 17. As a result, the transfer roller 17 transfers the toner image on the photosensitive drum 14 onto the paper S (transfer operation).

  As shown in FIGS. 1 and 2, the cleaning device 18 includes a cleaning blade 35 that contacts the outer peripheral surface of the photosensitive drum 14. The cleaning blade 35 is formed in, for example, a substantially rectangular plate shape that is long in the front-rear direction by urethane resin. The cleaning blade 35 is supported inside a cleaning housing (not shown) and is disposed in parallel with the photosensitive drum 14. The cleaning blade 35 is pressed against the surface of the photosensitive drum 14 from the counter direction with respect to the rotation direction of the photosensitive drum 14. Thereby, the cleaning device 18 (cleaning blade 35) removes the toner remaining on the surface of the photosensitive drum 14 after the transfer. The cleaning device 18 has a recovery screw (not shown) for recovering the removed toner.

  As shown in FIG. 3, the control device 8 includes a CPU 40 (Central Processing Unit), a memory 41, a bus 42, and an interface 43. The CPU 40 and the memory 41 are connected by a bus 42.

  The CPU 40 executes arithmetic processing according to a program or the like. The memory 41 stores a program and the like necessary for image forming processing executed by the CPU 40. The interface 43 is connected to the optical scanning device 13, the driving device 20, the charging bias power source 25, the developing bias power source 33, the transfer bias power source 34, etc. (hereinafter referred to as “power source etc.”). Thereby, the control apparatus 8 can send out various control signals toward a power supply or the like.

  The control device 8 controls the exposure operation of the optical scanning device 13. Further, the control device 8 controls the rotational drive of the photosensitive drum 14 and the rollers 17, 22, 23, 31, 32 and the like via the drive device 20. Further, the control device 8 controls the charging operation of the charging device 15, the developing operation of the developing device 16, and the transfer operation of the transfer roller 17 via the bias power supplies 25, 33, and 34. Although illustration is omitted, the interface 43 is connected to each device constituting the printer 1, and various control signals are transmitted and received between the control device 8 and each device.

  Here, the operation of the printer 1 will be described with reference to FIGS. 1 and 2. For example, the control device 8 executes image forming processing based on image data transmitted from a personal computer (not shown) or the like as follows.

  The charging device 15 charges the photosensitive layer 14b of the photosensitive drum 14 via the charging roller 22 to which a charging bias is applied (charging operation). The optical scanning device 13 forms an electrostatic latent image on the photosensitive drum 14 (exposure operation) by performing exposure (see arrow P) corresponding to the image data on the photosensitive drum 14 (photosensitive layer 14b). The developing device 16 develops the electrostatic latent image on the photosensitive drum 14 into a toner image via a developing roller 31 to which a developing bias is applied (developing operation). On the other hand, the paper S is transported from the paper feed cassette 3 through the transport path 10 and passes between the photosensitive drum 14 and the transfer roller 17. The transfer roller 17 to which the transfer bias is applied transfers the toner image on the photosensitive drum 14 onto the conveyed paper S (transfer operation). The fixing device 7 fixes the toner image on the paper S by heating and pressurizing the conveyed paper S. The paper S after the fixing process is discharged to the paper discharge tray 4. Further, the toner remaining on the photosensitive layer 14 b of the photosensitive drum 14 after the transfer is removed by the cleaning device 18. Further, the charge remaining on the photosensitive layer 14b is removed by a static eliminator (not shown).

  Incidentally, as shown in FIG. 2, the seal member 24 of the charging device 15 according to the first embodiment is provided in the case 21 so as to be in contact with the photosensitive drum 14. Since the seal member 24 slides relatively on the photosensitive drum 14, the seal member 24 may vibrate violently due to frictional force. Such vibration of the seal member 24 may propagate and resonate in the apparatus main body 2 to generate abnormal noise. In particular, since a large frictional force is generated between the photoconductor drum 14 and the seal member 24 when new, a large abnormal noise may occur. Therefore, the charging device 15 according to the first embodiment has a configuration that reduces the frictional force generated between the photosensitive drum 14 and the seal member 24 before the first image forming process is executed.

  As shown in FIG. 4, a toner layer 50 is formed on the seal member 24 of the charging device 15. The toner layer 50 is configured to act as a lubricant between the contact end portion 24a of the seal member 24 and the surface of the photosensitive drum 14 (see FIG. 2). The toner layer 50 is formed by applying toner to a range including the contact end portion 24a of the seal member 24 with respect to the photosensitive drum 14. The contact end portion 24a of the seal member 24 is a tip portion of the seal member 24 that contacts the photosensitive drum 14, and includes a tip surface and an edge portion.

  The toner layer 50 is formed on the surface (left side surface 24b) of the seal member 24 on the upstream side in the rotation direction of the photosensitive drum 14 (see FIG. 2). Specifically, the toner layer 50 is formed at least in a range from the contact end portion 24a of the seal member 24 to a position about 2 mm away. In other words, the height range in which the toner layer 50 is formed is set in a range of 2 mm or more from the contact end portion 24a and the height H or less of the seal member 24 in front view. The toner layer 50 only needs to be formed on at least the left side surface 24b of the seal member 24 on the upstream side in the rotation direction of the photosensitive drum 14, and in addition to the left side surface 24b, the right side surface and the front end surface of the seal member 24. It may be formed. The layer thickness of the toner layer 50 is not particularly set, but is preferably set experimentally and empirically so as to function as a lubricant.

  Further, the toner layer 50 is formed on the surface of the seal member 24 before the first image formation is performed. In the printer 1 according to the first embodiment, the toner layer 50 is formed on the surface of the seal member 24 by the control device 8 executing toner application control.

  Hereinafter, toner application control will be described with reference to FIGS. 2 and 5 to 7. 5 is a flowchart of the toner application control executed by the control device 8. FIG. 6 is a cross-sectional view schematically showing the charging device 15 and the like during toner application control. FIG. 7 is a cross-sectional view schematically showing the charging device 15 and the like in a state where a toner layer is formed. Since the toner layer 50 is not formed before the toner application control is executed, the toner layer 50 is shown by a two-dot chain line in FIG.

  For example, the operator operates an operation panel (not shown) of the printer 1 to instruct the control device 8 to execute toner application control. The toner application control is preferably executed when the printer 1 is started for the first time (for example, during an operation check operation performed before factory shipment or after installation at a place of use).

  As shown in FIGS. 2 and 5, when the toner application control is started, the control device 8 controls the rotational drive of the photosensitive drum 14 so as to execute the normal image forming process already described (S1). ). That is, the photosensitive drum 14 rotates (forward rotation) in a direction in which an image can be formed. Further, the control device 8 controls the charging operation of the charging device 15, the exposure operation of the optical scanning device 13, and the developing operation of the developing device 16 so as to execute normal image forming processing (S2 to S4). That is, the charging operation, the exposure operation, and the developing operation are sequentially executed.

  At this time, the optical scanning device 13 performs exposure corresponding to a dedicated pattern for toner application control on the photosensitive drum 14. The dedicated pattern for controlling toner application is formed in a band shape over the entire axial direction of the photosensitive drum 14 in an area where the toner image can be carried. Therefore, when the electrostatic latent image corresponding to the dedicated pattern is developed, a belt-like toner image (hereinafter referred to as “toner belt T”) is formed. Note that a dedicated pattern for toner application control is stored in advance in the memory 41 of the control device 8.

  As shown in FIGS. 5 and 6, after the toner band T is formed on the photosensitive drum 14, the control device 8 controls the driving device 20 to stop the rotational driving of the photosensitive drum 14 (S5). ). Subsequently, the control device 8 controls the driving device 20 to rotate the photosensitive drum 14 in the direction opposite to that at the time of image formation (S6). As the photosensitive drum 14 rotates in the reverse direction, the toner band T on the photosensitive drum 14 passes through the developing device 16 and the charging device 15 and is conveyed to the front of the cleaning device 18 (cleaning blade 35). When the toner band T is conveyed between the seal member 24 and the cleaning blade 35, the control device 8 controls the driving device 20 to stop the rotational driving of the photosensitive drum 14 (S7). Note that the control device 8 preferably controls the drive device 20 so as to stop the rotation after rotating the photosensitive drum 14 forward and backward for a predetermined time (or a fixed angle), for example.

  Then, as shown in FIGS. 5 and 7, the control device 8 controls the drive device 20 to rotate the photosensitive drum 14 in the forward direction (S8). The toner band T is conveyed toward the seal member 24 by the photosensitive drum 14 that rotates in the forward direction, and is blocked by the contact end portion 24 a of the seal member 24. The toner constituting the toner band T adheres to the left side surface 24b including the contact end portion 24a to form the toner layer 50. Finally, the control device 8 controls the driving device 20 to stop the photosensitive drum 14 (S9).

  As described above, the toner layer 50 is formed on the seal member 24 by executing the toner application control. Then, a normal image forming process is executed with the toner layer 50 formed.

  According to the charging device 15 according to the first embodiment described above, the seal member 24 is in contact with the surface of the photosensitive drum 14 with the toner layer 50 interposed therebetween. The toner layer 50 serves as a lubricant and reduces the frictional force acting between the photosensitive drum 14 and the seal member 24. In addition, the first image forming process is executed in a state where the toner layer 50 is formed on the seal member 24. Therefore, for example, even when the photoconductor drum 14 and the seal member 24 are new when the frictional resistance is large, the seal member 24 can smoothly move relative to the surface of the photoconductor drum 14 while being in contact therewith. Thereby, since the vibration of the seal member 24 due to the frictional force is suppressed, it is possible to prevent the generation of abnormal noise based on the vibration.

  Note that the toner layer 50 is gradually worn out and disappears in due to repeated execution of the image forming process. When the toner layer 50 disappears, the photosensitive drum 14 and the seal member 24 are slightly worn, and the frictional force generated between them is reduced. For this reason, in the state in which the image forming process is repeatedly executed, no large noise is generated.

  Further, according to the charging device 15 according to the first embodiment, the toner layer 50 is formed at a position having the largest frictional resistance in the contact range between the photosensitive drum 14 and the seal member 24. Therefore, the toner layer 50 can effectively reduce the frictional force between the photosensitive drum 14 and the seal member 24. Thereby, generation | occurrence | production of abnormal noise can be prevented effectively. The applicant of the present application can exhibit a good noise prevention effect by providing the toner layer 50 at a position 2 mm away from the contact end portion 24a of the seal member 24 on the upstream side in the rotation direction of the photosensitive drum 14. Confirm that there is.

  The control device 8 of the printer 1 according to the first embodiment executes toner application control in which the toner supplied from the developing device 16 to the photosensitive drum 14 is conveyed to the seal member 24 to form the toner layer 50. According to such a printer 1, the toner layer 50 is formed on the seal member 24 only by causing the control device 8 to execute toner application control. Thus, the toner layer 50 can be formed easily and quickly without changing the design or adding to the structure of the printer 1 or the charging device 15. Further, for example, the efficiency related to the operation of forming the toner layer 50 can be drastically improved as compared with the case where the operator accesses the inside of the printer 1 and manually applies the toner to the seal member 24. For example, even when the worn photosensitive drum 14 or the seal member 24 is replaced with a new one, the toner layer can be easily and quickly formed by executing the toner application control.

  The driving device 20 rotates the photosensitive drum 14 and a plurality of rollers, but the present invention is not limited to this. For example, a plurality of driving devices (such as motors) may be provided to rotate the photosensitive drum 14, the charging device 15, the developing device 16, and the transfer roller 17 respectively.

  Next, a charging device 60 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view schematically showing the charging device 60 and the jig 61 that supports the charging device 60. In addition, about the structure similar to above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the same description is abbreviate | omitted.

  In the charging device 15 according to the first embodiment described above, the toner layer 50 is formed on the seal member 24 when the control device 8 executes toner application control. On the other hand, the charging device 60 according to the second embodiment is different in that the toner layer 50 is formed on the seal member 24 before being incorporated in the device main body 2. Specifically, the toner layer 50 of the charging device 60 according to the second embodiment is formed using a jig 61. Note that the structure of the charging device 60 according to the second embodiment is the same as that of the charging device 15 according to the first embodiment, and a description thereof will be omitted.

  The jig 61 has substantially the same structure as the developing device 16 of the printer 1 according to the first embodiment. The jig 61 includes a developing roller 63 that is pivotally supported inside the housing 62. Although details will be described later, an assembled charging device 60 (toner layer 50 is not formed) is set on the jig 61.

  The housing 62 has an opening 62a on the upper right side, and is formed in a substantially rectangular box shape that is long in the front-rear direction. A toner supply source 70 is connected to the casing 62 via a pipe or the like (not shown). As a result, toner is supplied from the toner supply source 70 into the housing 62. The developing roller 63 is formed in a cylindrical shape that is long in the front-rear direction, and a part of the developing roller 63 is exposed from the opening 62 a of the housing 62. The developing roller 63 is connected to a power source (not shown) for applying a developing bias. A pair of screws 64 that circulate the toner while stirring are provided inside the housing 62. The developing roller 63 and the pair of screws 64 are rotationally driven by a driving device (not shown).

  In addition, support portions 65 are provided at both front and rear ends of the housing 62. The pair of front and rear support portions 65 are disposed so as to face each other with the opening 62a of the housing 62 sandwiched from both the front and rear sides. The pair of front and rear support portions 65 are configured to engage with the case 21 of the charging device 60 disposed in the opening 62 a of the housing 62.

  Next, the operation of the jig 61 will be described. The operator enters the charging device 60 (the toner layer 50 is not formed) between the pair of front and rear support portions 65, and causes the seal member 24 to enter the housing 62 from the opening 62a. In this state, the charging device 60 is supported by the pair of front and rear support portions 65 in a state where the left side surface 24 b of the seal member 24 is in contact with the surface of the developing roller 63. At this time, the angle θ formed by the left side surface 24b of the seal member 24 and the tangent at the contact portion of the seal member 24 with the developing roller 63 is preferably 30 degrees or more and 60 degrees or less.

  Next, the worker drives the jig 61 by performing a predetermined operation. That is, the developing roller 63 and each screw 64 to which a developing bias is applied are rotated. The toner carried on the surface of the developing roller 63 is conveyed toward the seal member 24 and is blocked by the contact end portion 24 a of the seal member 24. As a result, the toner layer 50 is formed on the left side surface 24 b including the contact end portion 24 a of the seal member 24.

  Next, the operator removes the charging device 60 from the jig 61 and incorporates the charging device 60 into the apparatus main body 2 of the printer 1.

  According to the charging device 60 according to the second embodiment described above, like the charging device 15 according to the first embodiment, the frictional force that the toner layer 50 acts between the photosensitive drum 14 and the seal member 24. Reduce. Thereby, since the vibration of the seal member 24 due to the frictional force is suppressed, it is possible to prevent the generation of abnormal noise based on the vibration.

  Although the charging device 60 is set in the jig 61 described above, only the seal member 24 may be set in the jig 61 instead. In this case, the seal member 24 is attached to the case 21 after the toner layer 50 is formed.

  In the present embodiment, the case where the present invention is applied to the monochrome printer 1 has been described as an example. .

  The description of the above embodiment shows one aspect of the charging device according to the present invention and an image forming apparatus including the same, and the technical scope of the present invention is not limited to the above embodiment. The components in the above embodiment can be appropriately replaced or combined with existing components and the like, and the description of the above embodiment does not limit the content of the invention described in the claims. .

1 Printer (image forming device)
8 Controller 14 Photosensitive drum (image carrier)
15 Charging Device 16 Developing Device 21 Case 22 Charging Roller (Charging Member)
24 sealing member 24a contact end 50 toner layer

Claims (5)

A charging member that contacts the rotating image carrier and charges the image carrier during image formation;
A case provided to cover a contact portion between the charging member and the image carrier;
A seal member provided in the case in a posture in contact with the image carrier,
On the surface of the seal member, a toner layer is formed by applying toner in a range including a contact end portion of the seal member with respect to the image carrier,
The charging device according to claim 1, wherein the toner layer is formed on a surface of the seal member before the first image formation is performed.   2. The charging device according to claim 1, wherein the toner layer is formed at least on a surface of the seal member on an upstream side in the rotation direction of the image carrier.   The charging device according to claim 2, wherein the toner layer is formed in a range at least up to a position 2 mm away from a contact end portion of the seal member.   An image forming apparatus comprising the charging device according to claim 1. A developing device that supplies toner to the image carrier that is rotationally driven while carrying an electrostatic latent image to develop the electrostatic latent image into a toner image;
A control device for controlling at least the rotational driving of the image carrier and the developing operation of the developing device;
The control device rotates the image carrier in a direction opposite to that at the time of image formation, and transports toner supplied from the developing device to the image carrier to the seal member to form the toner layer. The image forming apparatus according to claim 4, wherein control is executed.

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