Patent Grant
11726426
The present invention relates to an image forming apparatus that forms an image on a recording material.
An image forming apparatus of a toner replenishing type is known as an electrophotographic image forming apparatus. The image forming apparatus of the toner replenishing type includes an apparatus main body to and from which a toner container that stores toner can be attached and detached in a state in which a developing container that includes a photosensitive drum and a developing roller is in the apparatus main body. The apparatus has an advantage of being able to continue image formation by replacing only the toner container in a case where the apparatus runs out of toner.
On the other hand, as discussed in Japanese Patent Application Laid-Open No. 2005-77520, a configuration is widely used in which a process unit needs to be taken out to access a sheet jammed inside an apparatus main body of an image forming apparatus.
According to an aspect of the present invention, an image forming apparatus to and from which a toner container containing toner can be attached and detached, the image forming apparatus being configured to form a toner image on a recording material, includes a process unit including a photosensitive drum configured to carry a toner image, a developing roller configured to supply toner to the photosensitive drum, and a toner storage unit configured to store the toner to be carried by the developing roller, the toner storage unit being provided with a replenishing port through which the toner is replenished into the toner storage unit, a transfer member configured to come into contact with the photosensitive drum and form a transfer nip portion, for transferring the toner image on the photosensitive drum to the recording material, together with the photosensitive drum, a conveyance path through which the recording material conveyed by the transfer nip portion passes, an operation unit configured to operate the image forming apparatus, a frame configured to support the process unit, the frame including an opening portion for accessing the conveyance path from a front surface side being a side facing a display surface of the operation unit, and an opening and closing member configured to be movable between a closed position at which the opening portion is covered by the opening and closing member and an open position at which the opening portion is opened by the opening and closing member, wherein the image forming apparatus is configured so that the toner container can be attached to the replenishing port in a state in which at least part of the toner container is located on an outside of the image forming apparatus and the toner storage unit can be replenished with the toner through the replenishing port, wherein the process unit is configured to be rotatable relative to the frame about a rotation axis extending in a rotation axis direction of the photosensitive drum between a first position at which the photosensitive drum comes into contact with the transfer member and forms the transfer nip portion and a second position at which the photosensitive drum is separated from the transfer member, and wherein a direction in which the process unit rotates from the first position to the second position is a direction in which the replenishing port moves away when the process unit is viewed from the front surface side.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An image forming apparatus 1 according to a first exemplary embodiment is a monochrome printer using an electrophotographic method that forms an image on a recording material based on image information input from an external device. A configuration of the image forming apparatus 1 is described with reference to the attached drawings. [Overall Configuration]
As illustrated in
The image forming unit 10 includes a scanner unit 11, a process unit 20, and a transfer roller 12 that transfers the toner image formed on a photosensitive drum 21 of the process unit 20 to the recording material. The process unit 20 includes the photosensitive drum 21, a charging roller 22 arranged in a periphery of the photosensitive drum 21, and a developing device 30 that includes a pre-exposure device 23 and a developing roller 31.
The photosensitive drum 21 is a photosensitive member formed into a cylindrical shape. The photosensitive drum 21 according to the present exemplary embodiment has a photosensitive layer formed of a negatively charged organic photoreceptor on a drum shaped base substance molded from aluminum. Further, the photosensitive drum 21 as an image bearing member is rotationally driven by a motor in a predetermined direction (a clockwise direction in the drawing) at a predetermined process speed.
The charging roller 22 comes into contact with the photosensitive drum 21 with a predetermined press contact force and forms a charging portion. A charging high voltage power source applies a desired charging voltage to the charging roller 22, and thus a surface of the photosensitive drum 21 is uniformly charged to a predetermined potential. In the present exemplary embodiment, the photosensitive drum 21 is charged to negative polarity by the charging roller 22. The pre-exposure device 23 eliminates a surface potential of the photosensitive drum 21 before the surface thereof enters the charging portion to stably generate discharge in the charging portion.
The scanner unit 11 scans and exposes the surface of the photosensitive drum 21 to a laser beam by irradiating the photosensitive drum 21 with the laser beam corresponding to image information input from the external device, using a polygon mirror. An electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 21 by the exposure. The scanner unit 11 is not limited to a laser scanner device, and, for example, a light emitting diode (LED) exposure device including an LED array in which a plurality of LEDs is arranged in a longitudinal direction of the photosensitive drum 21 may be adopted.
The developing device 30 includes the developing roller 31 as a developer carrying member that carries developer, a developing container 32 serving as a frame of the developing device 30, and a supply roller 33 that can supply toner to the developing roller 31. The developing roller 31 and the supply roller 33 are rotatably supported by the developing container 32. The developing roller 31 is placed in an opening portion of the developing container 32 to face the photosensitive drum 21. The supply roller 33 is rotatably brought into contact with the developing roller 31 and applies the toner stored in the developing container 32 to a surface of the developing roller 31.
The developing device 30 uses a contact developing method as a developing method. In other words, a toner layer carried by the developing roller 31 comes into contact with the photosensitive drum 21 in a developing portion (developing area) in which the photosensitive drum 21 faces the developing roller 31. A developing high voltage power source applies a developing voltage to the developing roller 31. The toner carried by the developing roller 31 is transferred from the developing roller 31 to the drum surface based on potential distribution on the surface of the photosensitive drum 21 under the developing voltage, and thus the electrostatic latent image is developed into the toner image.
The developing container 32 is provided with a stirring member 34 as a stirring unit inside thereof. The stirring member 34 is driven by a not-illustrated motor and rotates to stir the toner in the developing container 32 and to feed the toner to the developing roller 31 and the supply roller 33. The stirring member 34 also has a role in circulating the toner that is not used for development and stripped from the developing roller 31 in the developing container 32 and making the toner in the developing container 32 uniform.
The feed unit 60 includes a front door 61 openably and closably supported by the image forming apparatus 1, a stacking tray 62, and a pickup roller 65. The stacking tray 62 forms a bottom surface of a recording material storage space that appears in a case where the front door 61 is opened. The front door 61 closes the recording material storage space in a state of being closed with respect to the image forming apparatus 1 and supports a recording material P together with the stacking tray 62 and an intermediate plate 63 in a state of being opened with respect to the image forming apparatus 1.
The fixing unit 70 uses a thermal fixing method in which image fixing processing is performed by heating and melting the toner on the recording material. The fixing unit 70 includes a fixing film 71, a fixing heater such as a ceramic heater that heats the fixing film 71, a thermistor that measures a temperature of the fixing heater, and a pressure roller 72 that is brought into pressure contact with the fixing film 71.
As illustrated in
Next, an image forming operation of the image forming apparatus 1 is described. In a case where a command to form an image is input to the image forming apparatus 1, the image forming unit 10 starts an image forming process based on image information input from an external computer connected to the image forming apparatus 1. The scanner unit 11 irradiates the photosensitive drum 21 with the laser beam based on the input image information. At that time, the photosensitive drum 21 has been charged by the charging roller 22 in advance, and by the photosensitive drum 21 being irradiated with the laser beam, an electrostatic latent image is formed on the photosensitive drum 21. Subsequently, the electrostatic latent image is developed by the developing roller 31, and the toner image is formed on the photosensitive drum 21.
In parallel with the above-described image forming process, the pickup roller 65 in the feed unit 60 feeds the recording material P supported by the front door 61 and the stacking tray 62. The recording material P is fed to a registration roller 15 by the pickup roller 65 and is conveyed to a transfer nip formed by the transfer roller 12 and the photosensitive drum 21 in synchronization with transfer timing of the toner image.
A transfer high voltage power source applies a transfer voltage to the transfer roller 12 as a transfer member, and the toner image carried by the photosensitive drum 21 is transferred to the recording material P conveyed by the registration roller 15. The recording material P to which the toner image is transferred is conveyed to the fixing unit 70, and the toner image is heated and pressed when passing through a nip portion between the fixing film 71 and the pressure roller 72 in the fixing unit 70. Accordingly, toner particles are melted and then fixed, so that the toner image is fixed to the recording material P. The recording material P that has passed through the fixing unit 70 is discharged to the outside of the image forming apparatus 1 by the discharge roller pair 80 and is stacked on a discharge tray 81 formed on the upper part of the image forming apparatus 1.
As illustrated in
A toner replenishing method is described.
As illustrated in
The opening and closing member 83 is opened, and thus a replenishing port 32a for toner replenishment that is formed on an upper surface of the developing container 32 is exposed from the opening portion 82a of the discharge tray 81. A user can access the replenishing port 32a without opening the top cover 82. The user attaches the toner pack 40 as a toner container filled with replenishment toner to the replenishing port 32a in a state in which the process unit 20 is in the image forming apparatus 1. Then, as illustrated in
The image forming apparatus 1 according to the present exemplary embodiment adopts a cleaner-less configuration in which transfer residual toner remaining on the photosensitive drum 21 without being transferred to the recording material P is collected in the developing device 30 and reused. The transfer residual toner is removed by the following processes. The transfer residual toner is a mixture of toner charged to positive polarity and toner that is charged to the negative polarity but does not have sufficient charge. The charge of the photosensitive drum 21 after transfer is removed by the pre-exposure device 23, and a uniform discharge is caused by the charging roller 22 so that the transfer residual toner is charged to the negative polarity again. The transfer residual toner that is charged to the negative polarity again in the charging portion reaches the developing portion as the photosensitive drum 21 rotates. Then, a surface area of the photosensitive drum 21 that has passed through the charging portion is exposed to light by the scanner unit 11 in a state in which the transfer residual toner adheres to the surface, and the electrostatic latent image is written thereon.
Behavior of the transfer residual toner that has reached the developing portion is described separately for an exposure portion and a non-exposure portion of the photosensitive drum 21. The transfer residual toner adhering to the non-exposure portion of the photosensitive drum 21 is transferred to the developing roller 31 at the developing portion due to a potential difference between a potential (a dark portion potential) of the non-exposure portion of the photosensitive drum 21 and the developing voltage and is collected in the developing container 32. This is because the developing voltage to be applied to the developing roller 31 has the positive polarity relative to the potential of the non-exposure portion on the assumption that normal charging polarity of the toner is the negative polarity. The toner collected in the developing container 32 is stirred and dispersed by the stirring member 34 in the toner in the developing container 32 and is used again in a developing process by being carried by the developing roller 31.
Meanwhile, the transfer residual toner adhering to the exposure portion of the photosensitive drum 21 remains on the drum surface without being transferred from the photosensitive drum 21 to the developing roller 31 in the developing portion. This is because the developing voltage to be applied to the developing roller 31 has the potential even more negative than that of the exposure portion (light portion potential) on the assumption that the normal charging polarity of the toner is the negative polarity. The transfer residual toner remaining on the drum surface is carried by the photosensitive drum 21 together with other toner to be transferred from the developing roller 31 to the exposure portion, moves to a transfer portion, and is transferred to the recording material P in the transfer portion.
As described above, in the present exemplary embodiment, the cleaner-less configuration is employed that collects the transfer residual toner in the developing device 30 and reuses the transfer residual toner, but a conventionally known configuration may be employed that collects the transfer residual toner using a cleaning blade abutting on the photosensitive drum 21. In this case, the transfer residual toner collected by the cleaning blade is collected in a collection container that is installed separately from the developing device 30. However, the cleaner-less configuration can eliminate the need for a transfer residual toner collection container, eliminate the need for taking out the process unit 20 from the image forming apparatus 1 to discard the toner in the collection container, and thus improve the usability. Further, an installation space of the collection container is not necessary, so that the image forming apparatus 1 can be further downsized, and a printing cost can be reduced by reusing the transfer residual toner. [Configurations of Developing Container and Toner Pack]
Next, configurations of the developing container 32 and the toner pack 40 are described.
As illustrated in
The protruding portion 37 communicates with the storage chamber 36 in the developing container 32 and extends from the storage chamber 36 toward the front surface F and obliquely upward. Thus, the replenishing port 32a formed in the protruding portion 37 is arranged on an upper part on a side of the front surface F of the image forming apparatus 1, and the replenishing port 32a of the developing container 32 can easily be accessed.
A void through which a laser L (refer to
As described above, since the protruding portion 37 on which the replenishing port 32a is formed is provided on one end side in the longitudinal direction of the developing container 32, a laser passage space through which the laser L emitted from the scanner unit 11 can pass is secured, and thus the image forming apparatus 1 can be downsized.
The toner pack 40 includes a first shutter member 41 that is rotatable and opens and closes a discharge port of the toner pack 40, and a plurality of protrusions 42 formed to correspond to a plurality of groove portions 32b formed in the replenishing port 32a. In a case where a user replenishes the developing container 32 with the toner, the user attaches the toner pack 40 to the replenishing port 32a of the developing container 32. The image forming apparatus 1 is configured so that the toner pack 40 can be attached to the replenishing port 32a in a state in which at least part of the toner pack 40 is exposed to the outside of the image forming apparatus 1. If the toner pack 40 is rotated 180 degrees in this state, the first shutter member 41 of the toner pack 40 comes in contact with a second shutter member 38 of the replenishing port 32a. As a result, the first shutter member 41 of the toner pack 40 rotates about a shutter rotation axis 38a together with the second shutter member 38 of the replenishing port 32a. Then, the toner can be replenished through an inlet of the developing container 32 and a replenishing port of the toner pack 40. The first shutter member 41 rotates with respect to a main body of the toner pack 40. Accordingly, the toner stored in the toner pack 40 leaks down from the toner pack 40, and the leaked toner enters the hollow protruding portion 37 through the replenishing port 32a.
The protruding portion 37 has an inclined plane 37a at a position facing an opening of the replenishing port 32a, and the inclined plane 37a is inclined downward toward the storage chamber 36. Thus, the toner replenished through the replenishing port 32a is guided by the inclined plane 37a to the storage chamber 36. The stirring member 34 conveys the toner in a conveyance direction orthogonal to the longitudinal direction of the developing container 32.
In other words, the toner replenished through the replenishing port 32a arranged on an upstream side in the conveyance direction of the stirring member 34 is conveyed to a downstream side in the conveyance direction while being leveled off in the longitudinal direction by stirring by the stirring member 34. Accordingly, the toner is spread over the entire length of the developing container 32 and can be appropriately conveyed toward the developing roller 31 and the supply roller 33 by the stirring member 34.
In the present exemplary embodiment, the toner pack 40 is configured to be a plastic bag member which is easily deformable, as illustrated in
[Posture of Process Unit]
A posture of the process unit 20 in the image forming apparatus 1 is described. In the image forming apparatus 1, the process unit 20 according to the present exemplary embodiment can take a first posture at which an image can be formed and a second posture for handling a jam occurred inside the image forming apparatus 1.
As illustrated in
As described above, if the process unit 20 is shifted from the first posture to the second posture, a void C is formed above the process unit 20 (
In the configuration according to the present exemplary embodiment, the jam clearance operation of the recording material can be performed by accessing the conveyance path of the recording material without taking the process unit 20 out of the image forming apparatus 1. As described above, in the configuration according to the present exemplary embodiment, replenishment is performed by the user attaching the toner pack 40 to the replenishing port 32a in a case where the process unit 20 is in the first posture, so that it is not necessary to take out the process unit 20 from the image forming apparatus 1 at the time of toner replenishment. Further, the configuration according to the present exemplary embodiment is the cleaner-less configuration that does not include the collection container for used toner. Thus, it is not necessary to take out the process unit 20 from the image forming apparatus 1 to replace the collection container. In other words, in the image forming apparatus 1 according to the present exemplary embodiment, since the user does not need to take out the process unit 20 from the image forming apparatus 1, usability can be greatly improved.
An orientation of the replenishing port 32a of the process unit 20 changes with the rotation of the process unit 20.
Alternatively, in the first posture, the replenishing port 32a may be provided in a tilted orientation in which the shutter rotation axis 38a extends downward in the direction from the front surface F toward the rear surface R of the image forming apparatus 1. In this configuration, in a case where the process unit 20 is in the first posture, the replenishing port 32a faces the side of the front surface F, and thus attachability of the toner pack 40 to the replenishing port 32a is further improved.
As described above, according to the present exemplary embodiment, the user does not need to take out the process unit from a main body of the apparatus for performing the jam clearance operation, thereby usability can be improved.
Further, at the time of the jam clearance operation, the process unit rotates in the direction in which the replenishing port is difficult to be seen from the side of the front surface of the image forming apparatus and the toner pack is difficult to be attached. Therefore, it is possible to prevent the toner pack from being accidentally attached for replenishment in the jam clearance operation.
In the present exemplary embodiment, the image forming apparatus of the toner replenishing type is described, but the present invention can also be applied to an image forming apparatus that includes a process cartridge that can be attached to and detached from a frame.
A second exemplary embodiment of the present invention is described. A configuration similar to that of the first exemplary embodiment is omitted from illustration or denoted by the same reference numeral in the drawings.
By the rotary cam 53 moving outward, the drum drive gear 51 arranged on an outer side of the rotary cam 53 in the rotation axis direction of the photosensitive drum 21 also moves in the rotation axis direction of the photosensitive drum 21 together with the rotary cam 53. Accordingly, coupling engagement between the driving coupling 51a of the drum drive gear 51 and the driven coupling 50a of the photosensitive drum gear 50 is released. The drum drive gear 51 is urged inward by an urging member 56 in the rotation axis direction of the photosensitive drum 21. Thus, in a case where the drum drive gear 51 moves outward together with the rotary cam 53, the drum drive gear 51 moves against an urging force of the urging member 56. Conversely, as illustrated in
Next,
As illustrated in
Next, a configuration of an image forming apparatus 1G according to the second exemplary embodiment is described.
A difference from the first exemplary embodiment is that the side cover 57G of the process unit 20G has a pressing rib 58 (a protruding shape). As illustrated in
In the configuration according to the second exemplary embodiment, the profiles of the frame cam portion 54 and the rotary cam 53 can be gently inclined, so that an operation force of the top cover 82 does not change significantly. Accordingly, operability of the top cover 82 can be improved.
The present invention is not limited to the above-described exemplary embodiments, and various modifications can be made without departing from the spirit and the scope of the present invention. Therefore, the following claims are attached to publicize the scope of the present invention.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2019-215829 | Nov 2019 | JP | national |
This application is a Continuation of International Patent Application No. PCT/JP2020/043552, filed Nov. 24, 2020, which claims the benefit of Japanese Patent Application No. 2019-215829, filed Nov. 28, 2019, both of which are hereby incorporated by reference herein in their entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 11506991 | Choi | Nov 2022 | B2 |
| 20050276631 | Mori | Dec 2005 | A1 |
| 20080317481 | Nagano | Dec 2008 | A1 |
| 20210103235 | Oshima | Apr 2021 | A1 |
| Number | Date | Country |
|---|---|---|
| H04-32854 | Feb 1992 | JP |
| 2001-175044 | Jun 2001 | JP |
| 2005-077520 | Mar 2005 | JP |
| 2005-242213 | Sep 2005 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20220276587 A1 | Sep 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/043552 | Nov 2020 | US |
| Child | 17748978 | US |
