Patent Application
20120201563
1. Technical Field
The present invention relates to an image forming apparatus that forms an image by developing the image using a liquid developing agent including a carrier liquid and toner particles and relates to a latent image carrying unit and a developing unit.
2. Related Art
Hitherto, a liquid developing type image forming apparatus has been practically used, in which an electrostatic latent image is formed on a charged photoreceptor and a toner image is formed by developing the electrostatic latent image using a liquid developing agent obtained by dispersing toner particles in a carrier liquid. For example, in an image forming apparatus disclosed in JP-A-9-15980 (FIG. 1), an oil pan is attached to an apparatus main body and developing equipment is loaded on the oil pan so as to perform the developing process. Such a configuration is adopted so as to prevent occurrence of a problem in which a liquid developing agent leaks from the developing equipment and is dispersed inside the apparatus.
As described above, the oil pan serves as an independent component attached to the apparatus main body, which is a main factor that restricts the arrangement space for the respective components of the apparatus and degrades the degree of freedom in design. Further, in order to realize a simple function of receiving the liquid developing agent leaking from the developing equipment, the independent component needs to be installed, which is a factor that increases the cost of the apparatus.
An advantage of some aspects of the invention is that it provides a technique capable of preventing the inside of the apparatus from being contaminated by reliably collecting the liquid developing agent leaking from the developing section while saving space and reducing cost.
According to a first aspect of the invention, there is provided an image forming apparatus including: a latent image carrying drum on which a latent image is formed; a charging section that includes a corona charger charging the latent image carrying drum and an air flow duct formed in the corona charger so as to be long in the rotation axis direction of the latent image carrying drum and making air flow in the corona charger; and a developing section that is disposed above the air flow duct in the vertical direction, is formed so as to be shorter than the air flow duct in the rotation axis direction of the latent image carrying drum, and develops the latent image formed on the latent image carrying drum by a liquid developing agent including toner and a carrier liquid.
Further, according to a second aspect of the invention, there is provided a latent image carrying unit including: a latent image carrying drum on which a latent image is formed; a charging section that includes a corona charger charging the latent image carrying drum and an air flow duct formed in the corona charger so as to be long in the rotation axis direction of the latent image carrying drum and making air flow in the corona charger; and a developing section that is disposed above the air flow duct in the vertical direction, is formed so as to be shorter than the air flow duct in the rotation axis direction of the latent image carrying drum, and develops the latent image formed on the latent image carrying drum by a liquid developing agent including toner and a carrier liquid.
In the image forming apparatus and the latent image carrying unit with such a configuration, the developing section extends in the rotation axis direction so as to develop the latent image on the latent image carrying drum using the liquid developing agent, and the liquid developing agent leaking from the developing section is dispersed in the rotation axis direction and drops downward in the vertical direction. Then, when the liquid developing agent is dispersed inside the apparatus, the inside of the apparatus is contaminated, which induces various troubles. However, in a case where the developing section is installed so as to be positioned above the upper surface of the charging air flow member in the vertical direction, that is, the upper surface of the charging air flow member is present below the developing section in the vertical direction, as in the aspect of the invention, the upper surface of the charging air flow member is formed so as to be longer than the charging member and the developing section in the rotation axis direction of the latent image carrying drum. Accordingly, the ambient atmosphere of the entire charging member is reliably ventilated and the liquid developing agent leaking and dropping from the developing section is received by the upper surface of the charging air flow member, thereby reliably preventing the inside of the apparatus from being contaminated by the liquid developing agent.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Hereinafter, the first and second aspects of the invention will be described.
In the image forming apparatus, the surface of the photosensitive drum 1 is provided with a photosensitive layer which is formed of a photosensitive material such as amorphous silicon photoreceptor. Then, the photosensitive drum 1 is disposed so that the rotary shaft thereof is parallel to or substantially parallel to the main-scanning direction (the direction perpendicular to the drawing paper of
In the circumference of the photosensitive drum 1, the following sections are arranged in the rotation direction D1 of the photosensitive drum 1 (in
The charging section 3 includes six chargers 31 and a charger air flow duct 32. In the drawing paper of
Further, the charger air flow duct 32 includes an external air introduction path 321 which introduces external air toward the charger 31 and an exhaust path 322 which discharges the ambient atmosphere of the charger 31 generated by the discharging process in the charger 31. Then, the atmosphere is managed by making air flow in the charger 31 in a manner such that the air flow is generated in the atmosphere where the charging process is performed and the exhaust operation is performed. Furthermore, the charger air flow duct 32 has a function of receiving and collecting a liquid developing agent exiting and dropping from the developing section 5 in addition to such a function of ventilating the ambient atmosphere of the charger 31. However, the specific configuration and effect will be described later in detail.
The exposure section 4 is disposed at the right side of the virtual vertical line VL of the drawing paper of
The liquid developing agent is applied from the developing section 5 to the electrostatic latent image formed in this way, and the electrostatic latent image is developed by toner. In the embodiment, a liquid developing agent is used in which colored resin particles serving as toner particles with a weight ratio of approximately 25% is dispersed inside a carrier liquid mainly containing an insulating liquid. Here, the toner particles have charges so that the charges may be electrophoresed in the electric field. Furthermore, the concentration of the developing agent is not limited to 25%, but may be in the range of 10 to 30%. Further, as the carrier liquid, for example, Isopar (the trademark of Exxon Corporation), silicon oil, normal paraffin oil, or the like is used. Further, the electrical resistance is 1010 Ω·cm or more and desirably 1012 Ω·cm or more. This is because an excessive current flows and an electric field necessary for the movement may not be maintained during a process in which the toner particles are electrophoresed when the resistance is low. Furthermore, the viscosity of the liquid developing agent which is produced in this way is dependent on a resin forming the toner particles or a dispersing agent and a charge control agent. However, a liquid developing agent which has a viscosity of 50 to 500 [Pa·s] may be used, and in the embodiment, a liquid developing agent of 400 [Pa·s] is used.
The developing section 5 of the image forming apparatus is disposed at the right side of the virtual vertical line VL of the drawing paper of
Further, the intermediate coating roller 52 and the anilox roller 53 are installed so as to supply the liquid developing agent to the developing roller 51, and the liquid developing agent is supplied from the anilox roller 53 to the developing roller 51 through the intermediate coating roller 52. In these rollers, the intermediate coating roller 52 has a configuration in which an elastic layer is formed on an outer peripheral portion of a metallic inner core as in the developing roller 51. On the contrary, the anilox roller 53 is a roller of which a surface is provided with a concave pattern such as a spiral groove that is minutely and evenly carved so as to easily store the liquid developing agent therein. Of course, the anilox roller 53 may have a configuration in which a rubber layer such as urethane or NBR is wound on a metallic core or a PFA tube is coated thereon as in the developing roller 51 or the intermediate coating roller 52. The intermediate coating roller 52 and the anilox roller 53 are connected to the above-described developing motor, and respectively rotate in the clockwise direction and the counter-clockwise direction in the drawing paper of
Further, a cleaning roller 511 comes into contact with the developing roller 51, and a roller cleaning blade 512 comes into contact with the cleaning roller 511, thereby performing a cleaning process on the developing roller 51. That is, the cleaning roller 511, which is installed at the downstream of the developing position where the surface of the developing roller 51 comes into contact with the photosensitive drum 1 so as to form a developing nip therebetween in the rotation direction D51 of the developing roller, rotates in the clockwise direction of the drawing paper of
On the other hand, a regulation member 531 comes into contact with the anilox roller 53. As the regulation member 531, a metallic member or an elastic member which is formed by coating an elastic material on the surface thereof may be used. However, the regulation member 531 according to the embodiment includes a rubber portion which is formed of urethane rubber or the like and comes into contact with the surface of the anilox roller 53 and a plate which is formed of metal and supports the rubber portion. Then, the regulation member 531 has a function of adjusting the film thickness, the amount, or the like of the liquid developing agent which is conveyed while being carried on the anilox roller 53 and of adjusting the amount of the liquid developing agent supplied to the developing roller 51. Further, the liquid developing agent which is scraped out by the regulation member 531 is returned to a storage portion 542 of the developing agent container 54. Furthermore, a stirring member 543 is disposed in the storage portion 542, and rotates by a motor (not shown) so that the liquid developing agent is stirred inside the storage portion 542.
With the above-described configuration, the developing roller 51 to which the liquid developing agent is supplied rotates so as to move in the direction opposite to the direction of the surface of the intermediate coating roller 52, and rotates so as to move in the same direction as the direction of the surface of the photosensitive drum 1. Furthermore, in order to form the toner image, the rotation direction of the developing roller 51 needs to be the complementary direction so that the surface rotates in the same direction as that of the surface of the photosensitive drum 1, but may be the opposite direction, the same direction, or any direction with respect to the intermediate coating roller 52.
Further, the toner compressing corona generator 55 is disposed along the rotation direction of the developing roller 51. More specifically, the toner compressing corona generator 55 is disposed at the upstream side of the developing position in the developing roller rotation direction D51. The toner compressing corona generator 55 is an electric field applying section which increases the bias of the surface of the developing roller 51. The electric field is applied to a position where the toner of the liquid developing agent which is conveyed by the developing roller 51 approaches the toner compressing corona generator 55, and the charging and compressing process is performed. Furthermore, in the toner charging and compressing process, a compaction roller performing a charging process through a contact may be used instead of the corona discharging process through the application of electrolyzation.
Further, the developing section 5 with such a configuration is connected to a developing equipment separating and contacting mechanism (not shown). When a control command is transmitted from a controller 10 to the developing equipment separating and contacting mechanism, the developing section 5 may reciprocate between a developing position (a position depicted by the solid line
The first squeeze section 6 is disposed at the downstream of the developing position in the rotation direction D1 of the photosensitive drum 1, and further the second squeeze section 7 is disposed at the downstream side of the first squeeze section 6. In the embodiment, a squeeze roller 61 of the first squeeze section 6 and a squeeze roller 71 of the second squeeze section 7 are both arranged at the left side of the virtual vertical line VL of the drawing paper of
The first squeeze section 6 is provided with the squeeze roller 61 which is biased toward the photosensitive drum 1 by a spring (not shown). Then, the squeeze roller 61 is rotationally driven by a motor (not shown) while coming into contact with the surface of the photosensitive drum 1 at the first squeeze position so that the excessive developing agent of the toner image is removed. Further, in the embodiment, in order to improve the squeezing efficiency, a first squeeze bias generating section (not shown) is electrically connected to the squeeze roller 61, and a first squeeze bias is applied thereto at an appropriate timing. Further, a cleaning blade 62 comes into contact with the surface of the squeeze roller 61 so that the liquid developing agent adhering to the surface of the roller is scraped out. Then, the liquid developing agent which is scraped out in this way is collected by a collection member 63.
Further, in the second squeeze section 7, the squeeze roller 71 rotates while coming into contact with the surface of the photosensitive drum 1 at a second squeeze position on the downstream side of the first squeeze position in the rotation direction D1 of the photosensitive drum 1 so that the excessive carrier liquid or the fogged toner of the toner image is removed. Further, in the embodiment, in order to improve the squeezing efficiency, as in the first squeeze section 6, a second squeeze bias generating section (not shown) is electrically connected to the squeeze roller 71, and a second squeeze bias is applied thereto at an appropriate timing. Further, a cleaning blade 72 comes into contact with the surface of the squeeze roller 71 so that the liquid developing agent adhering to the surface of the roller is scraped out. Then, the liquid developing agent which is scraped out in this way is guided by the guide member 73 in the direction separated from the photosensitive drum 1, and is collected in a collection member 74 disposed below the guide member 73 in the vertical direction.
Furthermore, in the embodiment, two squeeze sections 6 and 7 are provided, but the number or the arrangement of the squeeze sections is not limited thereto. For example, one squeeze section may be disposed.
A toner image which corresponds to the image signal transmitted to the outside of the apparatus is formed on the photosensitive drum 1 passing through the first and second squeeze sections 6 and 7, and the toner image is transferred to the blanket roller 21 at a primary transfer position TR1. The transfer section 2 which includes the blanket roller 21 is disposed at the left side of the virtual vertical line VL of the drawing paper of
The surface of the blanket roller 21 comes into contact with the surface of the photosensitive drum 1 at the upstream side of the rotation direction D1 of the photosensitive drum 1 in relation to the lowermost position BP of the photosensitive drum 1 in the vertical direction so as to form a primary transfer nip therebetween. The position where the primary transfer nip is formed corresponds to the primary transfer position TR1. Further, the blanket roller 21 is connected to a motor (not shown), and is rotationally driven in the clockwise direction D21 of the drawing paper of
Further, the secondary transfer roller 24 comes into contact with the blanket roller 21 so as to rotate in the complementary direction at the downstream of the primary transfer position TR1 in the rotation direction D21 of the blanket roller 21 so that a secondary transfer nip is formed therebetween. The position where the secondary transfer nip is formed corresponds to a secondary transfer position TR2. Accordingly, transfer paper is fed to the secondary transfer position TR2 by a conveying section (not shown) and passes through the secondary transfer nip, so that the toner image which is transferred to the blanket roller 21 is secondly transferred to the transfer paper. In this way, the image using the above-described liquid developing agent is printed on the transfer paper.
Further, the carrier coating mechanism 22 is disposed at the downstream side of the secondary transfer position TR2 in the rotation direction D21 of the blanket roller 21 so that the carrier liquid is coated on the surface of the blanket roller 21 after the secondary transfer process. In order to perform the carrier liquid coating process, the carrier coating mechanism 22 includes: a carrier coating roller 221 which rotates in the complementary direction with respect to the blanket roller 21; a carrier storing member 222 which stores the carrier liquid; and a carrier pumping roller 223 which supplies the carrier liquid to the carrier coating roller 221 by pumping the carrier liquid up from the carrier storing member 222.
The cleaning mechanism 23 is disposed at the downstream side of the carrier coating mechanism 22 and the upstream side of the primary transfer position TR1 in the rotation direction D21 of the blanket roller 21 so that the surface of the blanket roller 21 immediately before the primary transfer process is cleaned. In order to perform the cleaning process, the cleaning mechanism 23 includes: a cleaning roller 231 which rotates in the counter direction with respect to the blanket roller 21; a cleaning blade 232 which cleans the cleaning roller 231 while coming into contact with the cleaning roller 231; and a collection member 233 which collects the toner or the carrier liquid scraped out by the cleaning blade 232.
The cleaning mechanism 25 is disposed at the upstream side of the secondary transfer position TR2 in the rotation direction of the secondary transfer roller 24 so that the surface of the secondary transfer roller 24 before the secondary transfer process is cleaned. In order to perform the cleaning process, the cleaning mechanism 25 includes: a cleaning blade 251 which cleans the secondary transfer roller 24 while coming into contact with the secondary transfer roller 24 and a collection member 252 which collects the toner or the carrier liquid scraped out from the cleaning blade 251.
The photoreceptor cleaning section 8 is disposed at the downstream of the primary transfer position TR1 and the upstream side of the charging position in the rotation direction D1 of the photosensitive drum 1. The photoreceptor cleaning section 8 includes: a cleaning blade 81; a developing agent receiving member 82 which receives the liquid developing agent drooping from the lowermost position BP of the photosensitive drum 1; a collection member 83 which collects the developing agent received in the developing agent receiving member; and a support member 84 which integrally supports the cleaning blade 81, the developing agent receiving member 82, and the collection member 83. Then, the support member 84 is configured to be rotatable about the rotary shaft 85 serving as the rotation center.
Further, a spring member (not shown) is connected to the support member 84 so as to bias the support member 84 in the counter-clockwise direction of the drawing paper of
Next, the configuration and the effect of the charger air flow duct 32 will be described by referring to
Further, an upper surface 326 of the duct main body 323 is provided so that the lowermost end portion 5b of the developing section 5 is directed upward in the vertical direction, and in the upper surface 326, a fence 327 is formed upright along the entire circumference so as to form a collection space of the liquid developing agent. In the embodiment, as shown in
W31<W5<W32
For this reason, the lowermost end portion 5b of the developing section 5 is inserted into the collection space (the space where the upper surface 326 is surrounded by the fence 327). Further, a joint member 91 which is fixed to the bottom surface of the developing agent container 54 of the developing section 5 is also positioned above the collection space in the vertical direction. Accordingly, even when the liquid developing agent leaks and drops from the developing section 5 due to the developing process, the liquid developing agent is collected in the collection space. Further, in order to perform the replacement or the like of the developing section 5, there is a need to eliminate a pipe extending from the joint member 91 if necessary. Then, at this time, there is a possibility that the liquid developing agent may leak. However, as described above, since the collection space is present below the joint member 91 in the vertical direction, the leaking liquid developing agent may be reliably collected. Accordingly, the liquid developing agent which leaks and drops from the developing section 5 while reliably ventilating the entire ambient atmosphere of the charger 31 may be received in the upper surface 326 of the duct main body 323. Furthermore, since the fence 327 is formed upright along the entire periphery of the upper surface 326, the liquid developing agent which is received by the upper surface 326, that is, the waste liquid is prevented from overflowing from the upper surface 326. Accordingly, the waste liquid may be reliably stored in the collection space. Furthermore, since the charger air flow duct 32 is used at the time of collecting the waste liquid, there is no need to provide an independent component which prevents the leakage of the liquid developing agent from the developing section 5. As a result, it is possible to reliably prevent the inside of the apparatus from being contaminated by the liquid developing agent while saving space and reducing cost.
In this way, in the first embodiment, the photosensitive drum 1 corresponds to the “latent image carrying drum” of the invention. Further, the developing agent container 54 corresponds to the “container which stores the liquid developing agent” of the invention. Further, the fence 327 corresponds to the “wall portion” of the invention. However, the method of forming the fence 327 is not particularly limited. The fence 327 may be bonded to the upper surface 326 of the duct main body 323 by welding or the like or may be integrally formed with the duct main body 323.
In the first embodiment, the joint member 91 is fixed to the bottom surface of the developing agent container 54 of the developing section 5. However, in the second embodiment, as shown in
Then, in the second embodiment, the upper surface 326 of the duct main body 323 extends in the rotation axis direction X so as to correspond to the configuration in which the joint member 91 is disposed at the side surface of the developing section 5 in the rotation axis direction X. That is, the upper surface 326 of the duct main body 323 is longer than the distance W5 from the joint member 91 to the other side surface of the developing section 5 in the rotation axis direction X, and a collection space which is surrounded by the upper surface 326 and the fence 327 is also present below the joint member 91 in the vertical direction. Accordingly, the liquid developing agent which leaks and drops from the lowermost end portion 5b of the developing section 5 as well as the liquid developing agent which leaks when the pipe 92 is inserted to and extracted from the joint member 91 may be reliably collected. As a result, as in the first embodiment, it is possible to reliably prevent the inside of the apparatus from being contaminated by the liquid developing agent while saving space and reducing cost.
In the third embodiment, the upper surface 326 of the duct main body 323 is formed as an inclined surface which continuously descends as it moves away from the charger 31, and a step portion is formed at the end portion of the opposite side of the charger 31 (the right side of the drawing) and serves as a liquid storage portion 326a of the liquid developing agent. For this reason, the liquid developing agent which leaks from the developing section 5 and is received in the upper surface 326, that is, the waste liquid flows along the upper surface 326 and is stored in the liquid storage portion 326a. In this way, according to the embodiment, the leaking liquid developing agent may be easily collected.
Furthermore, in the third embodiment, the upper surface 326 of the duct main body 323 is finished as an inclined surface which continuously descends, but may be finished so as to be inclined in a step shape.
Further, as described above, in order to separate (collect and dispose) the waste liquid which is stored in the liquid storage portion 326a from the image forming apparatus, for example, as shown in
As described above, the wall portion may be disposed above the air flow duct in the vertical direction.
Further, the developing section includes the container which stores the liquid developing agent, the pipe which makes the liquid developing agent flow in the container, and the joint member which is disposed at one side of the developing section in the rotation axis direction of the latent image carrying drum so as to be used to attach and detach the pipe, wherein the air flow duct may be formed so as to be longer than the distance from the joint member to the other side opposite to the one side of the developing section in the rotation axis direction of the latent image carrying drum.
Further, the air flow duct may be formed so as to be inclined in a continuous or step shape.
Further, the air flow duct may be inclined downward in the vertical direction so as to be separated from the corona charger, the liquid storage portion of the liquid developing agent may be disposed at the opposite end portion of the corona charger, and the discharge drain may be connected to the liquid storage portion.
Further, the collection container may be disposed so as to collect the liquid developing agent while being connected to the discharge drain.
Furthermore, the exposure section which forms the latent image on the latent image carrying drum may be disposed between the charging section and the developing section, and the cover member may be disposed in the air flow duct so as to cover the upside of the exposure section in the vertical direction.
Furthermore, the invention is not limited to the above-described embodiments, and may be modified into various forms without departing from the spirit of the invention. For example in the above-described embodiments, a case has been described in which the invention is applied to an image forming apparatus with a so-called lower transfer structure. However, the invention may be applied to an image forming apparatus with a so-called upper transfer structure which is disposed above the virtual horizontal plane HP passing through the rotation center of the photosensitive drum 1 in the vertical direction so as to transfer an image carried on the photosensitive drum 1. Further, the application subject of the invention is not limited to the image forming apparatus, and the invention may be also applied to the image carrying section that includes the photosensitive drum 1, the charger 31, the charger air flow duct 32, and the developing section 5.
Further, in the above-described embodiments, the blanket roller 21 is used as the intermediate transfer medium, but instead of the roller, for example, a belt-like intermediate transfer body may be used.
Next, the third and fourth aspects of the invention will be described. Hitherto, a liquid developing type image forming apparatus has been practically used, in which an electrostatic latent image is formed on a charged photoreceptor and a toner image is formed by developing the electrostatic latent image using a liquid developing agent obtained by dispersing toner in a carrier liquid. For example, in an image forming apparatus disclosed in JP-A-2009-175425 (FIG. 1), a developing unit which includes a charging member (corresponding to the “charging member” of the invention) is used. The charging member is disposed so as to face a developing roller and gives a charge to the liquid developing agent coated on the developing roller. Then, the charging member and the developing roller are integrally connected to each other by two side plates so as to move together, whereby the relative positional relationship therebetween is maintained to be constant.
However, in the existing developing unit, since the liquid developing agent including a carrier liquid and toner is used, a problem may arise in which the liquid developing agent adhering to the surface of the developing roller moves on the surface of the developing roller and droops when the developing process is stopped or the maintenance is performed. Accordingly, the liquid developing agent which droops and drops from the developing roller adheres to the charging member, and hence the charging member is contaminated, which is a factor that induces irregularity of an image. Accordingly, it is important to prevent the contamination of the charging member. However, there is no sufficient examination how the charging member is positioned when the developing roller is positioned, and the above-described problem arises.
An advantage of some aspects of the invention is that it provides a technique capable of preventing the charging member from being contaminated by the liquid developing agent in the developing unit that performs a developing process using the liquid developing agent charged by the charging member and the image forming apparatus equipped with the developing unit.
According to the third aspect of the invention, there is provided a developing unit including: developing equipment that includes a developing agent carrying roller carrying a liquid developing agent including toner and a carrier liquid and a charging member disposed below the virtual horizontal plane perpendicular to the virtual perpendicular plane passing through the rotation center of the developing agent carrying roller in the vertical direction so as to charge the liquid developing agent carried on the developing agent carrying roller; and a developing equipment supporting section that supports the developing equipment at a first position and a second position different from the first position and supports the developing equipment in a posture in which the charging member does not intersect with the virtual perpendicular plane when the developing equipment is supported at the first position and the second position.
Further, according to the fourth aspect of the invention, there is provided an image forming apparatus including: a latent image carrier on which a latent image is formed; an exposure section that forms the latent image by exposing a latent image carrier; a developing section that includes a developing agent carrying roller carrying a liquid developing agent including toner and a carrier liquid, a charging member which is disposed below the virtual horizontal plane perpendicular to the virtual perpendicular plane passing through the rotation center of the developing agent carrying roller in the vertical direction so as to charge the liquid developing agent carried on the developing agent carrying roller, and a support member supporting the developing agent carrying roller and the charging member and that develops the latent image; and a developing equipment supporting section that supports the developing equipment at a first position and a second position different from the first position and supports the developing equipment in a posture in which the charging member does not intersect with the virtual perpendicular plane when the developing equipment is supported at the first position and the second position.
In this way, in the developing unit and the image forming apparatus, the developing equipment supporting section supports the developing equipment at the first position and the second position. However, in any position, a posture is taken in which the charging member does not intersect with the virtual perpendicular plane. For this reason, it is possible to prevent a problem in which the liquid developing agent droops from the developing agent carrying roller and adheres to the charging member, so that the charging member is contaminated.
Next, the configuration and the effect of the developing section 5 will be described by referring to FIGS. 9 to 16C. The developing section 5 includes the developing equipment which develops the latent image carried on the photosensitive drum 1 and the developing equipment supporting section which supports the developing equipment at the developing position, the separation position, and the maintenance position. Furthermore, here, the configuration of respective components of the developing section 5 when the respective components are positioned at a position where the developing process is performed will be described, and the positioning operation of the developing equipment during the developing process, the separation process, and the maintenance process will be described.
The developing section 5 of the image forming apparatus has a so-called three-roller structure with the developing roller 51, the intermediate coating roller 52, and the anilox roller 53. In these rollers 51 to 53, all rotary shafts are arranged so as to be parallel to the rotary shaft of the photosensitive drum 1 and both end portions thereof are axially supported to the side plates 50A and 505 so as to be rotatable.
Further, the cleaning blade 521 comes into contact with the intermediate coating roller 52, so that the liquid developing agent which does not contribute to the developing process and remains on the intermediate coating roller 52 is scraped out and dropped from the surface of the intermediate coating roller 52. The end portion of the cleaning blade 521 on the opposite side of the intermediate coating roller (the right side of
W513<W522
For this reason, as shown in
Further, the toner compressing corona generator 55 is disposed at the upstream side of the developing position in the rotation direction D51 of the developing roller 51, and is fixed to the developing equipment supporting section 50. More specifically, in the drawing paper of
In this way, the main components of the developing equipment are respectively fixed to the developing equipment supporting section 50. Further, one end portion of the rotary shaft 56 is axially supported to the side plate 50A, and the other end portion thereof is axially supported to the side plate 50B. For this reason, the developing equipment is configured to be rotatable about the rotary shaft 56 serving as the rotation center while being supported by the developing equipment supporting section 50. Then, a moving mechanism 57 to be described later moves and positions the developing roller 51 to a contact position (
Next, the configuration and the operation of the moving mechanism 57 and the movement regulating mechanism 58 will be described by referring to
The rotary shaft 571 is connected to a motor (not shown), and is rotationally driven by the rotation of the motor. Then, as shown in
Then, when the rotary shaft 571 is rotated by 180° by the motor, the separation and contact cam 572 comes into contact with the cam follower 573 in accordance with the rotation, so that the developing equipment supporting section 50 is rotated in the clockwise direction about the rotary shaft 56 in the drawing paper of
Furthermore, when the developing process is performed, the movable member pin 582 is made to be retracted by the solenoid so that the movable member pin 582 is extracted from the notch portion 583. Thus, the locked state of the rotation member 581 is released. Accordingly, the rotation stopped state of the rotary shaft 571 is released, and the developing roller 51 approaches the photosensitive drum 1 so as to come into contact with the photosensitive drum with the rotation of the rotary shaft 571 using the motor.
As described above, according to the embodiment, since the toner compressing corona generator 55 is disposed so as to face the developing roller 51 below the virtual horizontal plane (not shown) passing through the rotary shaft 514 of the developing roller 51 in the vertical direction, when the liquid developing agent which droops and drops from the developing roller 51 adheres to the toner compressing corona generator 55, irregularity of an image occurs. However, in the embodiment, during the developing process, that is, during a time when the developing roller 51 is positioned at the contact position as shown in
Further, in the embodiment, the developing equipment supporting section 50 rotates about the rotary shaft 56 so that the developing roller 51 is also positioned at the separation position or the maintenance position other than the developing position. For example, when the developing roller 51 is positioned at the separation position, as shown in
Further, during a time when the developing roller 51 is positioned at the contact position (the developing position) so as to perform the developing process, as shown in
Further, even when the developing roller 51 is positioned at the separation position (
Furthermore, when the developing roller 51 is positioned at the maintenance position (
In this way, the “collection path member” of the invention is formed only by two inclined members 513 and 522 at the contact position and the separation position. Further, the “collection path member” of the invention is formed only by the inclined member 513 at the maintenance position. Then, even when the developing roller 51 is positioned at any position, since the developing equipment supporting section 50 supports the developing equipment in a posture in which the lowermost position BP2 of the inclined member 522 (at the maintenance position, the lowermost position BP1 of the inclined member 513) is positioned above the collection portion 541 of the developing agent container 54 in the vertical direction, the liquid developing agent (the waste liquid) which is scraped by the blades 512 and 521 may be reliably collected.
In this way, in the embodiment, the photosensitive drum 1 corresponds to the “latent image carrying drum” of the invention. Further, the intermediate coating roller 52 corresponds to the “supply roller” of the invention. Further, the developing roller 51 and the toner compressing corona generator 55 respectively correspond to the “developing agent carrying roller” and the “charging member” of the invention. Further, the collection portion 541 of the developing agent container 54 corresponds to the “collection portion” of the invention, and the cleaning roller 511 and the roller cleaning blade 512 correspond to the “developing agent carrier cleaning section” of the invention. Further, the cleaning blade 521 corresponds to the “supply roller cleaning member” of the invention.
However, in the above-described embodiments, the rotary shaft 56 is fixed to the apparatus main body frame FM so as to be parallel to the rotary shaft 514 of the developing roller 51, and the developing equipment supporting section 50 is configured to be integrally rotatable about the rotary shaft 56. Then, both end portions of the rotary shaft 514 of the developing roller 51 are axially supported to the side plates 50A and 50B of the developing equipment supporting section 50 at a position comparatively far from the rotary shaft 56. For this reason, it is desirable to improve the rigidity of the side plates 50A and 50B, but both side plates 50A and 50B are not easily synchronized with each other in position. Accordingly, at the contact position, the partial contact of the developing roller 51 may occur. Alternatively, at the separation position or the maintenance position, the liquid developing agent which adheres to the developing roller 51 moves to the shaft end portion and unnecessarily droops from the shaft end portion. Therefore, in the above-described embodiments, as shown in
As the first adjusting mechanism, one end portion of the rotary shaft 56 is fixed to the apparatus main body frame FM through a position adjusting mechanism 59. The position adjusting mechanism 59 moves one end portion of the rotary shaft 56 in the horizontal direction perpendicular to the rotation axis direction of the developing roller 51 by using a bolt 591 which protrudes from the right side of
Further, in the embodiment, as the second adjusting mechanism, a so-called eccentric bearing 561 with an inner bearing and an outer bearing which is eccentric with respect to the inner bearing is used. That is, one end portion of the rotary shaft 56 axially supports the side plate 50B through the eccentric bearing 561. Accordingly, for example, when the outer bearing indicated by the circle mark in the eccentric bearing 561 in the state shown in
Here, the image forming apparatus may include: supply roller which supplies the liquid developing agent to the developing agent carrier; a supply roller cleaning member which cleans the supply roller and collects and conveys the liquid developing agent; and a collection portion which is disposed below the supply roller cleaning member in the vertical direction so as to store the liquid developing agent conveyed by the supply roller cleaning member, wherein when the developing equipment supporting section may support the developing equipment in a posture in which the collection portion is positioned below the supply roller cleaning member in the vertical direction when the developing equipment is supported at the first position and the second position.
As described above, the image forming apparatus may include: a developing agent carrier cleaning section which cleans the developing agent carrier and collects the liquid developing agent and a collection path member which has one end portion disposed higher than the other end portion in the vertical direction and of which one end portion is disposed below the developing agent carrier cleaning member in the vertical direction and the other end portion is disposed above the supply roller cleaning member in the vertical direction.
Further, the axial length of the developing agent carrying roller of the other end portion of the collection path member may be set to be shorter than the axial length of the developing agent carrying roller of the supply roller cleaning member.
Further, the image forming apparatus may include: a first side plate which axially supports one end portion of the developing agent carrying roller; a second side plate which axially supports the other end portion of the developing agent carrying roller; a rotary shaft which has one end portion axially supporting the first side plate and the other end portion axially supporting the second side plate and rotates the developing equipment; and an adjusting mechanism which adjusts the positions of the developing agent carrying roller and the rotary shaft.
Further, one end portion of the rotary shaft may be displaced in the direction perpendicular to the rotary axis direction of the rotary shaft by the adjusting mechanism.
Furthermore, the first position may be set to a position where the latent image carrier and the developing agent carrying roller come into contact with each other, that is, the developing position.
Furthermore, the invention is not limited to the above-described embodiments, and may be modified into various forms without departing from the spirit of the invention. For example, in the above-described embodiments, when the developing roller 51 is positioned to the contact position and the separation position, the liquid developing agent (the waste liquid) which is scraped out by the roller cleaning blade 512 is conveyed to the upside of the collection portion 541 of the developing agent container 54 in the vertical direction by the inclined members 513 and 522. However, for example, as shown in
Further, in the above-described embodiments, a case has been described in which the invention is applied to an image forming apparatus with a so-called lower transfer structure. However, the invention may be applied to an image forming apparatus with a so-called upper transfer structure which is disposed above the virtual horizontal plane HP passing through the rotation center of the photosensitive drum 1 in the vertical direction so as to transfer an image carried on the photosensitive drum 1.
Furthermore, in the above-described embodiments, the blanket roller 21 is used, but instead of the roller, for example, a belt-like intermediate transfer body may be used.
The entire disclosure of Japanese Patent Application No. 2011-025937, filed Feb. 9, 2011 and No. 2011-031922, filed Feb. 17, 2011 are expressly incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-025937 | Feb 2011 | JP | national |
| 2011-031922 | Feb 2011 | JP | national |
