Patent Application
20160054677
This application is based upon, and claims the benefit of priority from, corresponding Japanese Patent Application No. 2014-169787 filed in the Japan Patent Office on Aug. 22, 2014, the entire contents of which are incorporated herein by reference.
Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
An image forming apparatus performs to develop a latent image formed on an image carrier, which is constituted of such as a photoreceptor, with a developing device to visualize the latent image as a toner image. The developing device houses a developer including toner in a developing container, includes a developing roller supplying the image carrier with developer, and includes a stir conveying member supplying the developing roller with the developer housed in the developing container with stirring and conveying the developer.
For ensuring a satisfactory image quality, a space between an outer peripheral surface of the developing roller and an outer peripheral surface of a photoreceptor drum (development gap) should be held with high accuracy. In view of this, an image forming apparatus including a developing pulley located at both ends of a rotation shaft of the developing roller and a pressing member located to press the developing roller to the photoreceptor drum is widely employed. In this image forming apparatus, the developing pulley is in contact with the outer peripheral surface of the photoreceptor drum and is rotationally driven with respect to the photoreceptor drum. This ensures the developing roller to rotate with respect to the photoreceptor drum in a state keeping a predetermined development gap.
A typical developing device employs a configuration including a development drive unit to rotatably drive the developing roller in the developing device and transmitting a rotary drive power from the developing device main body side to the development drive unit via a gear. Alternatively, it is also employed that a configuration including a replenishment drive unit to rotatably drive a toner replenishment screw of a toner replenishment container in the developing device and transmitting a rotary drive power from the developing device main body side to the replenishment drive unit via a gear.
An image forming apparatus transmitting a rotary drive power to a developing roller via a gear has been proposed.
An image forming apparatus according to one aspect of the disclosure includes an image forming apparatus body, a first driving mechanism, a first drive unit, an image carrier, a developing device, and a biasing member. The first driving mechanism is located in the image forming apparatus body. The first drive unit includes an input unit to which a rotary drive power is transmitted from the first driving mechanism. The image carrier carries an electrostatic latent image. The developing device is removably attachable to the image forming apparatus body. The developing device forms a toner image on the surface of the image carrier. The toner image corresponds to the electrostatic latent image. The biasing member biases the developing device toward the image carrier side. The developing device includes a developing roller supplying toner onto the image carrier, and a developing unit housing and supporting the developing roller. The first drive unit is located at one end portion in an axial direction of the developing roller. The developing unit swings to come close to the image carrier by the biasing member biasing the developing unit. The developing unit is swingable with respect to the first drive unit.
These as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description with reference where appropriate to the accompanying drawings. Further, it should be understood that the description provided in this summary section and elsewhere in this document is intended to illustrate the claimed subject matter by way of example and not by way of limitation.
Example apparatuses are described herein. Other example embodiments or features may further be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. In the following detailed description, reference is made to the accompanying drawings, which form a part thereof.
The example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the drawings, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
The following describes embodiments of the disclosure with reference to the drawings.
A description will be given of an image forming apparatus 1 according to one embodiment of the disclosure with reference to
The apparatus main body 3 internally includes an image forming unit, a fixing unit, a paper sheet conveyance passage, and similar unit (not shown). The image forming unit transfers a toner image to a supplied paper sheet based on image data retrieved from a host device such as a PC to form an image. The image forming unit includes a photoreceptor drum 8, a charging unit, an exposure unit, a developing device 2, a transfer roller, a cleaning blade, and similar unit. The photoreceptor drum 8 carries an electrostatic latent image (described below). The charging unit charges the surface of the photoreceptor drum 8. The exposure unit forms the electrostatic latent image corresponding to a document image on the surface of the photoreceptor drum 8 with such as a laser beam. The developing device 2 attaches developer to the formed electrostatic latent image to form a toner image (described below). The transfer roller transfers the toner image to a paper sheet. The cleaning blade removes a toner remaining on the surface of the photoreceptor drum. The fixing unit heats and applies pressure to the paper sheet, on which the toner image is transferred, to fix the toner image on the paper sheet.
On the right-side surface of the apparatus main body 3, a cover member 9 is mounted so as to be freely open and close facing to the apparatus main body 3. The developing device 2 described below is replaceable from the right-side surface of the apparatus main body 3 by opening the cover member 9.
Next, a description will be given of a detail structure of a periphery of the developing device 2. The image forming apparatus 1 is a tandem type color printer, and includes the developing devices 2 and the photoreceptor drums (image carriers) 8 corresponding to respective colors of magenta, cyan, yellow, and black. Basically, the developing devices 2 each have a similar configuration and perform similarly. Also, basically, the photoreceptor drums 8 each have a similar configuration and perform similarly.
As illustrated in
The developing container 22 constitutes the outside of the developing device 2. At the lower portion of the developing container 22, the developing container 22 is divided into a first conveying chamber 22c and a second conveying chamber 22d by a partition portion 22b. The first conveying chamber 22c and the second conveying chamber 22d house a developer containing a magnetic carrier and a toner. The developing container 22 rotatably holds the stir conveying member 23 and the developing roller 20. Further, the developing container 22 includes an opening 22a that exposes the developing roller 20 toward the photoreceptor drum 8.
The developing roller 20 faces to the photoreceptor drum 8. The developing roller 20 is located adjacent to the photoreceptor drum 8 with a predetermined space. The developing roller 20 supplies the photoreceptor drum 8 with toner. The stir conveying member 23 is located approximately downward of the developing roller 20. The regulating blade 21 is fixed and held onto the developing container 22 at the right obliquely downward of the developing roller 20.
The developing roller 20 includes a rotation shaft 20a, a magnetic pole member 20b, a development sleeve 20c, which is formed of a non-magnetic metallic material in a cylindrical shape, and similar component.
The rotation shaft 20a is rotatably supported to the developing container 22. This rotation shaft 20a holds the development sleeve 20c so as to rotate integrally with the rotation shaft 20a. Further, the rotation shaft 20a holds the magnetic pole member 20b made of a magnet at a position facing to a second spiral 23b with a predetermined distance from the development sleeve 20c.
As illustrated in
The first spiral 23a and the second spiral 23b stir the developer to charge the toner included in the developer to a predetermined level. This ensures the toner to be held onto carrier. At both end portions of the partition portion 22b, which divides the first conveying chamber 22c and the second conveying chamber 22d, in the long side direction (front and back direction of the paper sheet surface in
The developing container 22 includes bearing portions 22e and 22f that support a swinging shaft 10 secured to the apparatus main body 3 (see
As illustrated in
As illustrated in
The development drive unit 40 transmits rotary drive power to the developing roller 20 and the stir conveying member 23. As illustrated in
The input gear 41 is configured to receive the rotary drive power from a development driving mechanism (second driving mechanism) via a coupling joint 46. The development driving mechanism includes a motor, a gear train, and similar component, which are located in the apparatus main body 3 (not shown). The input gear 41 is configured to transmit the rotary drive power to the developing roller gear 42 and the transmission gears 43 and 44.
The developing roller gear 42 is secured to an end portion of the rotation shaft 20a of the developing roller 20. The developing roller gear 42 is configured to transmit the rotary drive power to the development sleeve 20c of the developing roller 20 to rotate the development sleeve 20c. The transmission gear 43 is secured to a transmission shaft 47 engaging with the second spiral 23b, while the transmission gear 44 is secured to a transmission shaft 48 engaging with the first spiral 23a. This ensures the development sleeve 20c, the first spiral 23a, and the second spiral 23b to rotate when the input gear 41 rotates.
The development drive unit 40 is secured to the developing container 22. This ensures the development drive unit 40 to swing centering the swinging shaft 10 when the developing container 22 swings centering the swinging shaft 10.
As illustrated in
The input gear 31 is configured to receive the rotary drive power from a replenishment driving mechanism (first driving mechanism) 51 via a gear 51a (see
The transmission member 32 includes the gear portion 32a and an engaging portion 32b. The gear portion 32a meshes with the input gear 31. The engaging portion 32b engages with the toner replenishment screw 12a (see
At the lower portion of the cover member 33, an insertion hole 33a to which the bearing portion 22f of the developing container 22 (see
A swing angle (swing range) of the developing container 22 with respect to the replenishment drive unit 30 is regulated. Specifically, as illustrated in
Next, a description will be given of a case where the developing device 2 and the photoreceptor drum 8 are mounted on the apparatus main body 3. Firstly, as illustrated in
Then, mounting the photoreceptor drum 8 from the top surface side of the apparatus main body 3 causes the photoreceptor drum 8 to press the developing pulley 20d of the developing roller 20. Accordingly, the developing container 22 and the development drive unit 40 reverse a little (swing in the left rotation direction).
In this embodiment, as described above, the developing container 22 is swingable with respect to the replenishment drive unit 30. This reduces the swing of the developing container 22 due to the rotary drive power, which is transmitted from the replenishment driving mechanism 51 to the replenishment drive unit 30, when the rotary drive power is transmitted from the replenishment driving mechanism 51, which is secured to the apparatus main body 3, to the replenishment drive unit 30. This reduces the variation of development gaps between the developing roller 20 and the photoreceptor drum 8 at both end portions of the developing roller 20, thus ensuring satisfactory image quality.
As described above, when the rotary drive power is transmitted to the replenishment drive unit 30 from the replenishment driving mechanism 51 via the gear 51a, the power causes the replenishment drive unit 30 to swing with respect to the developing container 22 with engaging of the gear 51a and the input gear 31. However, as described above, securing the replenishment drive unit 30 to the apparatus main body 3 can cause the apparatus main body 3 to absorb the power acting on the replenishment drive unit 30 to swing.
As described above, when the rotary drive power is transmitted to the development drive unit 40 from the development driving mechanism secured to the apparatus main body 3 via the coupling joint 46, the development drive unit 40 may be secured to the developing container 22 because the transmitted rotary drive power is less likely to act on the developing container 22 to swing.
As described above, the center shaft for swinging (swinging shaft 10) of the developing container 22 with respect to the replenishment drive unit 30 is coaxial with the center shaft for swinging (swinging shaft 10) of the developing container 22 with respect to the apparatus main body 3. This achieves space saving compared with the case where the center shaft for swinging of the developing container 22 with respect to the replenishment drive unit 30 is not coaxial with the center shaft for swinging of the developing container 22 with respect to the apparatus main body 3.
As described above, the developing container 22 includes the regulating piece 22i, while the replenishment drive unit 30 includes the regulating hole 33b. The regulating hole 33b regulates the swing range of the developing container 22 with respect to the replenishment drive unit 30 by the regulating piece 22i in contact with the regulating hole 33b. This ensures regulating the swing range of the developing container 22 with respect to the replenishment drive unit 30 easily.
For example, the above-described embodiment shows an exemplary case where the center shaft for swinging of the developing container 22 with respect to the replenishment drive unit 30 is located coaxially with the center shaft for swinging of the developing container 22 with respect to the apparatus main body 3. However, the disclosure should not be construed in a limiting sense. The center shaft for swinging of the developing container 22 with respect to the replenishment drive unit 30 may be located not coaxially with the center shaft for swinging of the developing container 22 with respect to the apparatus main body 3.
While in the above-described embodiment the developing container 22 is configured swingably with respect to the replenishment drive unit 30 and the development drive unit 40 is secured to the developing container 22, the disclosure should not be construed in a limiting sense. For example, the developing container 22 may be configured swingably with respect to the development drive unit 40. In this case, using such as a flexible joint ensures transmitting the rotary drive power from the development drive unit 40 to the developing container 22 easily. A drive unit other than the replenishment drive unit 30 may be located such that the developing container 22 is configured to be swingable with respect to the drive unit.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-169787 | Aug 2014 | JP | national |
