Image forming apparatus

Abstract

To provide an image forming apparatus which can suppress image defects caused by toner accumulated in a development device while suppressing the increase of size and cost of the apparatus.SOLUTION: An image forming apparatus 1 comprises a development device 412 which turns a latent image to a visual toner image by sticking toner onto it via a toner carrier (development roller 204) disposed opposingly at a latent image carrier (photoreceptor drum 413) on which the latent image is formed. The development device 412 comprises a driving transmission member 214 for transmitting driving force to a toner conveying member 202 for conveying the toner. The driving transmission member 214 performs an operation by switching between a first operation of transmitting the driving force for conveying the toner to the toner conveying member 202 and a second operation of vibrating a prevention member 208 which is provided to the development device 412 for preventing scattering of the toner.SELECTED DRAWING: Figure 7F

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] An image forming apparatus utilizing electrophotographic process technology charges the surface of a photoconductor drum, which is a latent image carrier, with a charging device. Next, the image forming apparatus forms an electrostatic latent image on the surface of the photoconductor drum by irradiating the surface with laser light based on image data. Next, the image forming apparatus visualizes the electrostatic latent image by supplying developer to the photoconductor drum with a developing device, and forms a toner image on the photoconductor drum. Next, the image forming apparatus transfers and fixes the toner image onto paper, thereby forming an image on the paper. In such image forming apparatuses, there is a problem that toner that has adhered to and accumulated on the developing device falls during image formation and adheres to the photosensitive drum, or is transferred to the transfer belt, causing image defects such as image smears.

[0003] To address such problems, Patent Documents 1 to 3 disclose image forming apparatuses that include a vibration unit that applies vibration to the housing of the developing device, thereby suppressing toner accumulation in the developing device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 09-211974 [Patent Document 2] JP 2005-099239 A [Patent Document 3] JP 2021-184038 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the vibration means described in Patent Documents 1 to 3 includes a tapping part that taps the housing of the developing device, which is a dedicated part for applying vibration to the housing of the developing device, and a movable part that moves the tapping part. When the vibration means is provided in the image forming device, a space for providing the vibration means within the device is required. Therefore, there is a problem that the device becomes large and the cost increases.

[0006] An object of the present invention is to provide an image forming apparatus capable of suppressing image defects caused by toner accumulated in a developing device while suppressing an increase in size or cost of the apparatus. [Means for solving the problem]

[0007] In order to solve the above problem, the image forming apparatus according to claim 1 comprises: a developing device that develops a latent image by attaching toner to the latent image via a toner carrier disposed opposite a latent image carrier on which the latent image is formed; the developing device includes a drive force transmission member that transmits a drive force to a toner transport member that transports the toner, The drive transmission member switches between a first operation of transmitting the drive force to the toner transport member to transport the toner, and a second operation of vibrating a prevention member provided in the developing device to prevent the toner from scattering.

[0008] The invention described in claim 2 is the image forming apparatus described in claim 1, The drive transmission member includes a first control unit that switches a rotation direction of the drive transmission member to switch between the first operation and the second operation.

[0009] The invention described in claim 3 is the image forming apparatus described in claim 2, The first control unit is a driving force transmission member that is greater than a rotational load of the toner transport member is transmitted to the toner transport member as the first operation by rotating the driving force transmission member in a first direction while an engaged portion of the driving force transmission member is engaged with an engaging portion of the toner transport member, and the toner is transported by rotating the toner transport member in the first direction; The drive transmission member is rotated in a second direction that is opposite to the first direction, and the drive transmission member is caused to perform the second operation while the rotation of the toner transport member is stopped.

[0010] The invention described in claim 4 is the image forming apparatus described in claim 3, The toner transport member includes a regulating member that regulates the toner transport member so as not to rotate in the second direction when the drive transmission member rotates in the second direction.

[0011] The invention described in claim 5 is the image forming apparatus described in claim 1, The drive transmission member transmits the drive force to the toner transport member via an engaged portion of the drive transmission member, which is in an engaged state in the first operation, and an engaging portion of the toner transport member.

[0012] The invention described in claim 6 is the image forming apparatus described in claim 5, The drive transmission member is displaceable along the axial direction of the toner transport member, and performs the second operation when displaced from a position in which the engaged portion and the engaging portion are disengaged to a position in which the engaged portion and the engaging portion are engaged.

[0013] The invention described in claim 7 is the image forming apparatus described in claim 1, The developing device includes an elastic member, The drive transmission member performs the second movement by utilizing the elastic force of the elastic member.

[0014] The invention described in claim 8 is the image forming apparatus described in claim 1, A detection unit that detects a rotation load of the toner transport member; a second control unit that does not restrict rotation of the toner transport member when the rotation load detected by the detection unit is greater than a predetermined value, and restricts rotation of the toner transport member when the rotation load is equal to or smaller than the predetermined value; Equipped with.

[0015] The invention described in claim 9 is the image forming apparatus described in claim 1, The toner transport member is connected to the prevention member via a rigid body.

[0016] The present invention relates to an image forming apparatus comprising: The second operation is performed simultaneously with an operation different from the second operation performed in the image forming apparatus. Effect of the Invention

[0017] According to the present invention, it is possible to suppress image defects caused by toner accumulation in the developing device while suppressing an increase in size or cost of the device. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing a schematic configuration of an image forming apparatus according to a first embodiment. [Diagram 2] 1 is a block diagram showing a functional configuration of an image forming apparatus according to a first embodiment. [Diagram 3] 2 is a schematic side view of the developing device according to the first embodiment; FIG. [Figure 4] 2 is a schematic diagram of the developing device according to the first embodiment, viewed from above in the vicinity of the device; [Diagram 5] 4 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a first direction. FIG. [Figure 6] FIG. 4 is a schematic diagram of a drive transmission member. [Figure 7A] 13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 7B]13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 7C] 13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 7D] 13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 7E] 13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 7F] 13 is a schematic diagram of the drive mechanism when the drive transmission member rotates in a second direction. FIG. [Figure 8] FIG. 11 is a diagram showing an effect of the second operation. [Figure 9] 11 is a schematic view of the vicinity of a developing device according to a second embodiment, as viewed from above. FIG. [Figure 10] FIG. 11 is a block diagram showing a control function in a rotation restricting operation according to a modified example of the second embodiment. [Figure 11] 13 is a schematic view of the vicinity of a developing device according to a modified example of the second embodiment, as viewed from above. FIG. [Figure 12] FIG. 11 is a schematic perspective view of the vicinity of a solenoid and a protruding member according to a modified example of the second embodiment. [Figure 13] 13 is a flowchart of a rotation control process according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the present embodiment will be described in detail with reference to the drawings, however, the scope of the invention is not limited to the illustrated examples.

[0020] [First embodiment] <1. Configuration of Image Forming Apparatus 1> Fig. 1 is a diagram showing an outline of the overall configuration of an image forming apparatus 1 according to an embodiment of the present invention, Fig. 2 is a block diagram showing the main functional configuration of the image forming apparatus 1 according to the embodiment. 1 and 2 is an intermediate transfer type color image forming apparatus that utilizes electrophotographic process technology. The image forming apparatus 1 transfers (primary transfer) toner images of each color, Y (yellow), M (magenta), C (cyan), and K (black), formed on a photoconductor drum 413, onto an intermediate transfer belt 421. Next, the image forming apparatus 1 superimposes the four color toner images on the intermediate transfer belt 421, and then transfers them onto paper S (secondary transfer), thereby forming an image.

[0021] The image forming apparatus 1 is of a tandem type in which photoconductor drums 413 corresponding to the four colors YMCK are arranged in series in the running direction of an intermediate transfer belt 421, and toner images of each color are transferred onto the intermediate transfer belt 421 in sequence.

[0022] As shown in FIG. 2, the image forming apparatus 1 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper conveying unit 50, a fixing unit 60, a storage unit 70, a communication unit 80, and a control unit 100.

[0023] The control unit 100 includes a central processing unit (CPU) 101, a read only memory (ROM) 102, a random access memory (RAM) 103, and the like. The CPU 101 reads out a program corresponding to the processing contents from the ROM 102, loads it into the RAM 103, and cooperates with the loaded program to centrally control the operations of the blocks of the image forming apparatus 1 shown in FIG.

[0024] The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder), a document image scanning device 12 (scanner), and the like. The automatic document feeder 11 conveys the document D placed on the document tray by a conveying mechanism and sends it to the document image scanning device 12. The automatic document feeder 11 can continuously read the images of multiple documents D placed on the document tray all at once.

[0025] The original image scanning device 12 optically scans an original document transported from the automatic document feeder 11 onto the contact glass or an original document placed on the contact glass. Next, the original image scanning device 12 forms an image of the reflected light from the original document on the light receiving surface of a CCD (Charge Coupled Device) sensor 12a, and reads the original image. The image reading unit 10 generates input image data based on the reading result by the original image scanning device 12. The image processing unit 30 performs a predetermined image processing on the input image data.

[0026] The operation display unit 20 includes, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display unit 21 and an operation unit 22. In accordance with a display control signal input from the control unit 100, the display unit 21 displays various operation screens, image statuses, operation statuses of various functions, and the like. The operation unit 22 includes various operation keys such as a numeric keypad and a start key, and receives various input operations by the user and outputs operation signals to the control unit 100.

[0027] The image processing unit 30 includes a circuit for performing digital image processing on the image data of the input job (input image data) according to initial settings or user settings. For example, the image processing unit 30 performs gradation correction based on gradation correction data under the control of the control unit 100. The image processing unit 30 performs various correction processes such as color correction and shading correction, compression processing, etc., in addition to gradation correction, on the input image data.

[0028] The image forming unit 40 forms an image using color toners of Y, M, C, and K components based on the input image data that has been image-processed by the image processing unit 30 . The image forming section 40 includes image forming units 41Y, 41M, 41C, and 41K, an intermediate transfer unit 42, and the like.

[0029] The image forming units 41Y, 41M, 41C, and 41K for the Y, M, C, and K components have the same configuration. For ease of illustration and explanation, common components are denoted by the same reference numerals, and when they are to be distinguished from one another, the reference numerals are denoted by the suffix Y, M, C, or K. In Fig. 1, reference numerals are given only to the components of the image forming unit 41Y for the Y component, and reference numerals are omitted for the components of the other image forming units 41M, 41C, and 41K.

[0030] The image forming unit 41 includes an exposure device 411, a developing device 412, a photoconductor drum 413, a charging device 414, a drum cleaning device 415, and the like.

[0031] The photoconductor drum 413 is an organic photoconductor in which a photosensitive layer made of a resin containing an organic photoconductor is formed on the outer peripheral surface of a drum-shaped metal base, for example. The photoconductor drum 413 functions as a latent image carrier. Control unit 100 controls a drive current supplied to a drive motor (not shown) that rotates photoconductor drum 413, thereby rotating photoconductor drum 413 at a constant peripheral speed.

[0032] The charging device 414 is, for example, a charger, and generates a corona discharge to uniformly charge the surface of the photoconductor drum 413 having photoconductivity to a negative polarity.

[0033] Exposure device 411 includes, for example, a semiconductor laser, and irradiates laser light corresponding to an image of each color component onto photoconductor drum 413. As a result, exposure device 411 forms an electrostatic latent image of each color component in the image area irradiated with the laser light on the surface of photoconductor drum 413 due to a potential difference with the background area.

[0034] The developing device 412 is a two-component developing device, and visualizes the electrostatic latent image by attaching toner of each color component to the surface of the photoconductor drum 413 to form a toner image, as will be described in detail later.

[0035] Drum cleaning device 415 has a drum cleaning blade or the like that is in sliding contact with the surface of photoconductor drum 413. Drum cleaning device 415 removes untransferred toner remaining on the surface of photoconductor drum 413 after primary transfer.

[0036] The intermediate transfer unit 42 includes an intermediate transfer belt 421, a primary transfer roller 422, a plurality of support rollers 423, a secondary transfer roller 424, a belt cleaning device 426, and the like.

[0037] The intermediate transfer belt 421 is an endless belt, and is stretched in a loop shape around a plurality of support rollers 423. At least one of the plurality of support rollers 423 is a drive roller, and the others are driven rollers. For example, it is preferable that the roller 423A, which is disposed downstream in the belt running direction from the primary transfer roller 422 for the K component, is the drive roller. This makes it easier to keep the running speed of the belt constant in the primary transfer portion. By rotating the roller 423A, the intermediate transfer belt 421 runs at a constant speed in the direction of the arrow A.

[0038] Primary transfer rollers 422 are disposed on the inner circumferential surface side of intermediate transfer belt 421, facing photoconductor drums 413 of the respective color components. Intermediate transfer unit 42 presses primary transfer roller 422 against photoconductor drum 413 with intermediate transfer belt 421 therebetween. In this way, intermediate transfer unit 42 forms a primary transfer nip for transferring a toner image from photoconductor drum 413 to intermediate transfer belt 421.

[0039] Secondary transfer roller 424 is disposed on the outer circumferential surface side of intermediate transfer belt 421, facing backup roller 423B disposed downstream in the belt running direction of roller 423A. In the intermediate transfer unit 42, the secondary transfer roller 424 is pressed against the backup roller 423B with the intermediate transfer belt 421 sandwiched therebetween. In this way, the intermediate transfer unit 42 forms a secondary transfer nip for transferring a toner image from the intermediate transfer belt 421 to the paper S.

[0040] When the intermediate transfer belt 421 passes through the primary transfer nip, the intermediate transfer unit 42 performs primary transfer by sequentially superimposing the toner image on the photoconductor drum 413 onto the intermediate transfer belt 421. Specifically, the intermediate transfer unit 42 applies a primary transfer bias to the primary transfer roller 422, and imparts a charge of the opposite polarity to the toner to the side of the intermediate transfer belt 421 that contacts the primary transfer roller 422. As a result, the intermediate transfer unit 42 electrostatically transfers the toner image onto the intermediate transfer belt 421.

[0041] Thereafter, when the paper S passes through the secondary transfer nip, the intermediate transfer unit 42 performs a secondary transfer of the toner image on the intermediate transfer belt 421 onto the paper S. Specifically, the intermediate transfer unit 42 applies a secondary transfer bias to the secondary transfer roller 424, and imparts a charge of the opposite polarity to the toner to the side of the paper S that contacts the secondary transfer roller 424. As a result, the intermediate transfer unit 42 electrostatically transfers the toner image onto the paper S. The paper transport section 50 transports the paper S onto which the toner image has been transferred towards the fixing section 60.

[0042] The belt cleaning device 426 has a belt cleaning blade or the like that slides and contacts the surface of the intermediate transfer belt 421. The belt cleaning device 426 removes untransferred toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer.

[0043] The intermediate transfer unit 42 may have a configuration in which a secondary transfer belt is stretched in a loop shape around a plurality of support rollers including a secondary transfer roller, instead of the secondary transfer roller 424. This configuration is a so-called belt-type secondary transfer unit.

[0044] The fixing unit 60 heats and presses the conveyed paper S onto which the toner image has been secondarily transferred, in a fixing nip, thereby fixing the toner image onto the paper S.

[0045] The paper transport section 50 includes a paper feed section 51, a paper discharge section 52, a transport path section 53, and the like. The three paper feed tray units 51a to 51c of the paper feed section 51 store paper S (standard paper, special paper) identified based on basis weight, size, etc., by preset type. The transport path section 53 has a plurality of transport roller pairs such as a registration roller pair 53a.

[0046] The paper transport section 50 sends out the paper S stored in the paper feed tray units 51a to 51c one by one from the top, and transports the paper S to the image forming section 40 via the transport path section 53. At this time, the registration roller section in which the registration roller pair 53a is arranged corrects the inclination of the fed paper S and adjusts the transport timing. Next, the image forming section 40 performs secondary transfer of the toner image on the intermediate transfer belt 421 all at once onto one side of the paper S. Next, the fixing section 60 fixes the secondary transferred toner image onto the paper. Next, the paper transport section 50 causes the paper S on which the image has been formed to be discharged outside the machine by the paper discharge section 52 equipped with the paper discharge roller 52a.

[0047] The storage unit 70 includes, for example, a non-volatile semiconductor memory, a hard disk drive, etc. The storage unit 70 stores various data related to the image forming apparatus 1, such as various setting information.

[0048] The communication unit 80 includes a communication control card such as a LAN (Local Area Network) card, etc. The communication unit 80 transmits and receives various data to and from an external device (such as a personal computer) connected to a communication network such as a LAN or a WAN (Wide Area Network).

[0049] 2. Configuration of Developing Device 412 Next, the configuration of the developing device 412 will be described in detail with reference to Figures 3 and 4. Figure 3 is a schematic diagram of the vicinity of the developing device 412 as seen from the side. Figure 4 is a schematic diagram of the vicinity of the developing device 412 as seen from above. Developing device 412 is of a two-component development type, and uses a two-component developer containing toner and carrier to develop the electrostatic latent image formed on photoconductor drum 413. In this way, developing device 412 forms a toner image on photoconductor drum 413.

[0050] The developing device 412 includes a developer housing 201 . The developer housing 201 contains a developer containing toner and a carrier. The developer housing 201 includes therein a toner transport member 202, a toner supply member 203, and a developing roller 204. The developing roller 204 functions as a toner carrier. In the example shown in FIGS. 3 and 4, the direction parallel to the rotation shaft 202a of the toner conveying member 202 is the X-axis direction, the horizontal direction perpendicular to the X-axis direction is the Y-axis direction, and the vertical direction perpendicular to both the X-axis direction and the Y-axis direction is the Z-axis direction.

[0051] The toner transport member 202 and the toner supply member 203 are disposed along the axial direction of the developing roller 204. The toner transport member 202 and the toner supply member 203 are screw-shaped members each including a central axis and a blade formed in a spiral shape around the central axis. The developer housing 201 includes an accommodation chamber 206 that accommodates a toner transport member 202, and an accommodation chamber 207 that accommodates a toner supply member 203. The accommodation chamber 206 and the accommodation chamber 207 are separated by a partition wall 205 that is disposed along the XZ plane. The toner transport member 202 and the toner supply member 203 are arranged in parallel with each other with a partition wall 205 interposed therebetween.

[0052] As shown in FIG. 4, the toner supplying member 203 includes a supply screw 203a, a reverse-winding screw 203b, and a discharge screw 203c, which are arranged coaxially in this order.

[0053] The supply screw 203 a supplies the developer to the developing roller 204 . In the following description, the developer transport direction when the supply screw 203a rotates forward is referred to as a "first transport direction H1," and the opposite direction is referred to as a "second transport direction H2." The reverse winding screw 203b is provided on the X-axis positive side of the supply screw 203a, and transports the developer in the opposite direction to the supply screw 203a. The discharge screw 203c is provided on the positive X-axis direction side of the reverse winding screw 203b.

[0054] The supply screw 203a transports the developer in a first transport direction H1 when it rotates forward. The reverse-winding screw 203b transports the developer in a second transport direction H2 when it rotates forward. The discharge screw 203c transports the developer in the first transport direction H1, which is the same as the supply screw 203a, when it rotates forward. As a result, the developer transported by the forward rotation of the supply screw 203a is hardly transported further toward the X-axis positive direction side than the reverse-winding screw 203b. In this case, the developer transported by the forward rotation of the supply screw 203a does not proceed toward the reverse-winding screw 203b, but bends its path and is transported toward the toner transport member 202.

[0055] As shown in FIG. 4, the containing chamber 207 has a discharge port 207a for discharging the developer at the end in the positive direction of the X-axis. The discharge port 207a opens downward from the inner bottom of the containing chamber 207. The developer discharged from the discharge port 207a falls into a waste developer storage unit (not shown) and is stored therein.

[0056] The toner transport member 202 transports the developer in the opposite direction to the supply screw 203a by being driven to rotate in the forward direction.

[0057] As shown in FIG. 4, the containing chamber 206 is provided with a supply port 206a for supplying the developer into the developer casing 201 at the end in the positive direction of the X-axis. A supply unit (not shown) including a developer storage unit in which replenishment developer is stored and a transport mechanism for transporting the replenishment developer from the developer storage unit is disposed above the supply port 206a of the developer housing 201. The replenishment developer is supplied to the storage chamber 206 from above through the supply port 206a. The replenishment developer joins the developer circulating in the circular circulation path inside the developer housing 201 and is transported by the toner transport member 202.

[0058] As shown in FIG. 4, the partition wall 205 has openings 205a and 205b. The opening 205a passes the developer from the toner transport member 202 to the supply screw 203a. The opening 205b delivers the developer from the supply screw 203a to the toner transport member 202. As a result, the developer circulates between the storage chambers 206 and 207. A part of the developer transported by the toner supply member 203 is supplied to the developing roller 204, and the developer is magnetically attracted onto the outer circumferential surface of the developing roller 204.

[0059] The image forming apparatus 1 replenishes the toner that has been consumed during image formation by replenishing the developer from the replenishing port 206a. At the same time, the image forming apparatus 1 discharges the developer from the discharge port 207a. In this way, the image forming apparatus 1 replaces the deteriorated carrier in the developer housing 201 with new replenished carrier, suppressing deterioration of the carrier circulating in the developer housing 201. The rotation ratio between the toner supply member 203 and the toner transport member 202 during forward rotation, the opening width of the openings 205a and 205b, and the number of turns of the reverse winding screw 203b are set to values ​​that can maintain the amount of developer in the developer housing 201 at a predetermined amount. In this embodiment, the rotation speed of the toner supplying member 203 is 466 rpm, and the rotation speed of the toner transporting member 202 is 491 rpm. The ratio of the rotation speeds of the toner supplying member 203 and the toner transporting member 202 is 0.95:1. In this embodiment, the opening width of the openings 205a and 205b is 32.5 mm, and the number of turns of the reverse winding screw 203b is 7.

[0060] The developing roller 204 faces the photoconductor drum 413 at the opening of the developer housing 201. For example, the developing roller 204 transports the developer attracted to the outer circumferential surface thereof toward a developing nip (or developing area) N, which is a portion facing the photoconductor drum 413. The developing roller 204 supplies toner to the photoconductor drum 413 at the developing nip N.

[0061] The developing device 412 includes a prevention member 208 provided on the upper side of the developing roller 204 . The prevention member 208 suppresses dust particles (scattered toner) caused by the developer that are generated when the developing roller 204 rotates.

[0062] The developing device 412 includes a suction section 209 that sucks up the scattered toner generated between the photoconductor drum 413 and the developing roller 204 . The suction unit 209 has a duct 209a arranged along the outer surface of the upper side of the developer housing 201, and a fan (not shown). A suction port 209b, which is the tip of the duct 209a, is installed at a position close to the developing roller 204 on the surface of the photosensitive drum 413. The fan provided in the suction unit 209 sucks air inside the duct 209a. As a result, the scattered toner generated between the photosensitive drum 413 and the developing roller 204 is taken into the duct 209a through the suction port 209b. After being transported through the duct 209a, the scattered toner is collected in a collection tank (not shown). The control unit 100 controls the start and stop of rotation of the fan provided in the suction unit 209, changes in the rotation speed, and the like.

[0063] In suction unit 209, toner may accumulate on the wall surface of duct 209a, and the accumulated toner may spill onto photoconductor drum 413 or paper, causing contamination inside image forming apparatus 1 or image defects that smear the image. In particular, near suction port 209b, a laminar flow generated by the rotation of developing roller 204 and a laminar flow generated by the rotation of photoconductor drum 413 intersect, generating a swirling airflow. Therefore, even if the suction air speed in suction unit 209 is increased, the toner cannot be completely sucked and collected near suction port 209b, and the toner tends to accumulate. The vicinity of suction port 209b is, for example, the tip portion of prevention member 208 (the end portion on the photoconductor drum 413 side).

[0064] In this embodiment, the image forming apparatus 1 crushes the toner accumulated on the prevention member 208 by applying vibration to the prevention member 208. Next, the image forming apparatus 1 collects the crushed toner by sucking it with the suction unit 209, or causes it to adhere to the development roller 204, thereby reducing the amount of toner accumulated on the prevention member 208. In this way, the image forming apparatus 1 suppresses image defects caused by the accumulated toner spilling onto the photoconductor drum 413 or the paper.

[0065] 3. Configuration of driving mechanism 210 FIG. 5A is a schematic diagram showing an example of the configuration of a drive mechanism 210 included in the developing device 412. As shown in FIG. The driving mechanism 210 rotates the toner transport member 202 about a rotation shaft 202a of the toner transport member 202 to transport the developer stored in the storage chamber 206. An end 202b of the rotation shaft 202a on the positive side of the X-axis is rotatably supported by a bearing 211 provided in the developer housing 201. The driving mechanism 210 applies vibration to the prevention member 208 to break up the toner accumulated on the prevention member 208 .

[0066] 5(a), the toner transport member 202 includes a screw member 202c disposed inside the developer housing 201, and an engagement member 202d disposed outside the developer housing 201. The screw member 202c and the engagement member 202d are integrally formed. The engaging member 202d is disposed in contact with the outer wall surface 201a of the developer housing 201 at the end portion 202b of the rotating shaft 202a. The engaging member 202d includes an engaging portion 202e that protrudes toward the positive X-axis direction at a predetermined angle with respect to the X-axis direction.

[0067] The drive mechanism 210 includes a drive motor 212 , an elastic member 213 , and a drive transmission member 214 . The drive transmission member 214 is a substantially cylindrical member as shown in FIG. Fig. 5(b) is a schematic diagram showing the positional relationship between the drive transmission member 214 and the end 202f of the engagement portion 202e as viewed from the negative direction of the X-axis. The hatched portion of the drive transmission member 214 shown in Fig. 5(a) is a cross-sectional view taken along line VV shown in Fig. 5(b).

[0068] Under the control of the controller 100, the drive motor 212 rotates the drive transmission member 214 around a rotation axis parallel to the X-axis direction by switching between a first direction and a second direction. The first direction is a positive rotation direction that is counterclockwise when viewed from the negative X-axis direction. The second direction is a reverse rotation direction that is clockwise when viewed from the negative X-axis direction opposite to the first direction. The elastic member 213 is a spring or the like provided along the X-axis direction between an inner wall surface 215 of the housing of the image forming apparatus 1 and the drive transmission member 214. The elastic member 213 is expandable and contractable in the X-axis direction.

[0069] The drive transmission member 214 includes an engaged portion 214a that engages with the engaging portion 202e of the engaging member 202d on an opposing surface 214d that faces the engaging member 202d. The engaged portion 214a has a generally right-angled trapezoidal shape in the XY plane. The engaged portion 214a includes a parallel portion 214b that is parallel to the X axis, and an inclined portion 214c that is inclined at a predetermined angle with respect to the X axis. The angle at which the inclined portion 214c is inclined relative to the X-axis is substantially the same as the angle at which the engaging portion 202e of the engaging member 202d is inclined relative to the X-axis, and the inclined portion 214c and the engaging portion 202e are parallel to each other. 6, the drive transmission member 214 has a through hole 214e at the center in the YZ plane. The through hole 214e passes through the drive transmission member 214 in the X-axis direction. A rotation shaft 214f ​​(see FIG. 9) of the drive transmission member 214 is inserted into the through hole 214e.

[0070] <4. Rotation in the first direction> Next, the operation of the driving mechanism 210 and the toner conveying member 202 when the drive transmission member 214 rotates in the first direction will be described. 5(a), the drive transmission member 214 is biased toward the engaging member 202d by the elastic force F1 of the elastic member 213. The engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are in an engaged state. The end portion 202f of the engaging portion 202e abuts against the parallel portion 214b of the engaged portion 214a. The opposing surface 214d of the drive transmission member 214 abuts against the opposing surface 202g, which is the surface of the engaging member 202d that faces the drive transmission member 214. In this state, the control unit 100 drives the driving motor 212 so as to rotate the driving transmission member 214 in the first direction. The rotational driving force of the driving motor 212 is transmitted to the rotating shaft 202a of the toner conveying member 202 via the engaged portion 214a of the driving transmission member 214 and the engaging portion 202e of the engaging member 202d, which are in an engaged state. At this time, the conveying force of the toner conveying member 202 rotating in the first direction to convey the developer is greater than the load that the toner conveying member 202 receives from the developer stored in the storage chamber 206. Therefore, the toner conveying member 202 rotates in the first direction about the rotation shaft 202a. As a result, the developer stored in the storage chamber 206 is conveyed from the negative X-axis direction side to the positive X-axis direction side. In the rotational operation in the first direction, the drive transmission member 214 and the toner transport member 202 rotate in the first direction while the engaged portion 214a and the engaging portion 202e remain in an engaged state.

[0071] As described above, in the rotational operation in the first direction, the drive transmission member 214 performs the first operation of transmitting the drive force for transporting the toner to the toner transport member 202. The control unit 100 rotates the drive transmission member 214 in the first direction in a state in which the engaged portion 214a of the drive transmission member 214 is engaged with the engaging portion 202e of the toner transport member 202. As a result, the control unit 100 causes the drive transmission member 214 to transmit a drive force larger than the rotational load of the toner transport member 202 to the toner transport member 202 as a first operation, thereby rotating the toner transport member 202 in the first direction to transport the toner. The drive transmission member 214 transmits the drive force of the drive motor 212 to the toner conveying member 202 via the engaged portion 214a of the drive transmission member 214 and the engaging portion 202e of the engaging member 202d, which are in an engaged state in the first operation.

[0072] <5. Rotation in the second direction> Next, the operation of the driving mechanism 210 and the toner conveying member 202 when the drive transmission member 214 rotates in the second direction will be described. 7A to 7F are schematic diagrams showing configuration examples of the drive mechanism 210 when the drive transmission member 214 rotates in the second direction.

[0073] The control unit 100 drives the drive motor 212 so that the drive transmission member 214 rotates in the second direction while the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are engaged with each other. When the drive transmission member 214 rotates in the second direction, as shown in (a) of Fig. 7A, the engaging portion 202e comes into contact with the inclined portion 214c of the engaged portion 214a. The hatched portion of the drive transmission member 214 shown in (a) of Fig. 7A is a cross-sectional view taken along line VIIA-VIIA shown in (b) of Fig. 7A.

[0074] Fig. 7B shows a state in which the control unit 100 has further rotated the drive transmission member 214 in the second direction from the state shown in Fig. 7A. In this embodiment, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer stored in the storage chamber 206 is greater than the transport force that transports the developer by the rotation of the toner transport member 202 in the second direction. Therefore, the toner transport member 202 does not rotate and remains stopped. At this time, as shown in (a) of Fig. 7B, the engaged portion 214a receives a force F2 from the engaging portion 202e at the inclined portion 214c. The hatched portion of the drive transmission member 214 shown in (a) of Fig. 7B is a cross-sectional view taken along line VIIB-VIIB shown in (b) of Fig. 7B. When engaged portion 214a receives force F2, drive transmission member 214 moves in the positive direction of the X axis, and opposing surface 214d of drive transmission member 214 and opposing surface 202g of engaging member 202d move away from each other. This causes elastic member 213 to contract in the X axis direction.

[0075] Fig. 7C shows a state in which the control unit 100 further rotates the drive transmission member 214 in the second direction from the state shown in Fig. 7B. As shown in Fig. 7C(a), the drive transmission member 214 further moves in the positive direction of the X-axis. The hatched portion of the drive transmission member 214 shown in Fig. 7C(a) is a cross-sectional view taken along line VIIC-VIIC shown in Fig. 7C(b). As the drive transmission member 214 moves further in the positive direction of the X-axis, the engagement between the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 is released, and the end portion 202f of the engaging portion 202e abuts against the opposing surface 214d of the drive transmission member 214. The elastic member 213 further contracts in the X-axis direction. The elastic member 213 shown in (a) of Fig. 7C is in its most contracted state.

[0076] Fig. 7D shows a state in which the control unit 100 has further rotated the drive transmission member 214 in the second direction from the state shown in Fig. 7C. As shown in Fig. 7D(a), the end 202f of the engagement portion 202e abuts against the opposing surface 214d of the drive transmission member 214, and the drive transmission member 214 rotates in the second direction while the elastic member 213 remains in the most contracted state. The shaded portion of the drive transmission member 214 shown in Fig. 7D(a) is a cross-sectional view taken along line VIID-VIID shown in Fig. 7D(b).

[0077] Fig. 7E shows a state in which the control unit 100 further rotates the drive transmission member 214 in the second direction from the state shown in Fig. 7D. As shown in Fig. 7E(a), the end 202f of the engaging portion 202e reaches the position of the parallel portion 214b of the engaged portion 214a, and the end 202f abuts against the parallel portion 214b. The hatched portion of the drive transmission member 214 shown in Fig. 7E(a) is a cross-sectional view taken along line VIIE-VIIE shown in Fig. 7E(b). When the end portion 202f comes into contact with the parallel portion 214b, the contraction of the elastic member 213 is released, and the elastic repulsive force F3 of the elastic member 213 moves the drive transmission member 214 in the negative X-axis direction.

[0078] Fig. 7F shows a state in which the control unit 100 has further rotated the drive transmission member 214 in the second direction from the state shown in Fig. 7E. As shown in Fig. 7F(a), the engaging portion 202e of the engaging member 202d and the engaged portion 214a of the drive transmission member 214 are in an engaged state. The hatched portion of the drive transmission member 214 shown in Fig. 7F(a) is a cross-sectional view taken along line VIIF-VIIF shown in Fig. 7F(b). The drive transmission member 214 moves further toward the negative X-axis direction due to the elastic repulsive force F3 of the elastic member 213. The opposing surface 214d of the drive transmission member 214 collides with the opposing surface 202g of the engagement member 202d. That is, the elastic repulsive force F3 accumulated in the elastic member 213 is released in a short time, causing the drive transmission member 214 to collide with the engagement member 202d. As a result, the drive transmission member 214 applies an impact force F4 to the screw member 202c of the toner transport member 202. The vibration caused by the impact force F4 received by the screw member 202c is transmitted to the prevention member 208 via the bearing 211 and the developer casing 201. When the prevention member 208 vibrates, the toner accumulated on the prevention member 208 is crushed, and the crushed toner is sucked and collected by the suction unit 209. Alternatively, the crushed toner adheres to the development roller 204.

[0079] When the control unit 100 further rotates the drive transmission member 214 in the second direction from the state shown in Figure 7F, the state returns to the state shown in Figure 7A. In the states shown in Figures 7A to 7F, the rotation of the toner transport member 202 remains stopped. The control unit 100 continues to rotate the drive transmission member 214 in the second direction, causing the drive transmission member 214 to repeatedly collide with the engagement member 202d.

[0080] As described above, in the rotational movement in the second direction, the drive transmission member 214 performs the second movement, which is a movement to vibrate the prevention member 208 provided in the developing device 412 for preventing the toner from scattering. The control unit 100 rotates the drive transmission member 214 in the second direction, and causes the drive transmission member 214 to perform a second operation while the rotation of the toner transport member 202 is stopped. The drive transmission member 214 is displaceable along the axial direction (X-axis direction) of the toner transport member 202. The drive transmission member 214 performs a second operation when displacing from a position in which the engaged portion 214a and the engaging portion 202e are disengaged to a position in which the engaged portion 214a and the engaging portion 202e are engaged with each other.

[0081] In the above-mentioned rotational movement in the first direction and the rotational movement in the second direction, the drive transmission member 214 switches between the first movement and the second movement. The control unit 100 switches the rotation direction of the drive transmission member 214 to switch between the first operation and the second operation of the drive transmission member 214. The control unit 100 functions as a first control unit.

[0082] <6. Effect of the second action> FIG. 8 shows the effect of suppressing image defects by the second operation. The example shown in FIG. 8 is a result of a durability evaluation performed on the image forming apparatus 1. The horizontal axis of Fig. 8 is the number of A4 size sheets printed by the image forming apparatus 1. The vertical axis is the toner spill occurrence rate, which is the ratio of the number of sheets on which image stains occurred due to toner spill to the number of sheets printed. The solid line shows the toner spill occurrence rate when the second operation is not performed. The dashed line shows the toner spill occurrence rate when the second operation is performed. In the durability evaluation, the temperature inside the image forming apparatus 1 is 23°C and the humidity is 50%. In the durability evaluation, each color coverage is 5%. In the durability evaluation, the image forming apparatus 1 performs continuous printing on A4 size paper. In the durability evaluation, the number of images stained by toner spillage is counted every 2,000 sheets printed, and the toner spillage occurrence rate is calculated. The target value for the toner spillage occurrence rate in the durability evaluation is 0.5% or less, and the durability evaluation period is for printing 350,000 sheets (developer life). As shown in Figure 8, when the second operation was not performed (without the second operation), the rate of toner spillage gradually increased as continuous printing was performed, and after printing 50,000 sheets, the rate of toner spillage was 1.2%, failing to reach the target. On the other hand, when the second operation of the present invention was performed every 3,000 sheets printed (when the second operation was performed), the toner spill rate was maintained at or below the target value of 0.5% during the period of printing 350,000 sheets, verifying that the target could be achieved.

[0083] [Second embodiment] Next, an image forming apparatus 1 according to a second embodiment will be described. In the following description, the same components as those in the image forming apparatus 1 according to the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0084] In the first embodiment, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer is greater than the transport force that transports the developer by the rotation of the toner transport member 202 in the second direction. Therefore, the toner transport member 202 does not rotate and remains stopped. In the second embodiment, when the drive transmission member 214 rotates in the second direction, the load that the toner transport member 202 receives from the developer is equal to or less than the transport force that transports the developer by the rotation of the toner transport member 202 in the second direction. In this case, the toner transport member 202 rotates in the second direction, and the developer in the developer housing 201 is transported in the opposite direction to the direction shown in FIG. 4. At this time, the developer in the developer housing 201 is discharged in excess from the discharge port 207a. As a result, the amount of developer in the developer housing 201 becomes less than a predetermined amount, and the amount of developer supplied to the developing roller 204 becomes insufficient, causing image defects such as screw pitch unevenness. The screw pitch unevenness is density unevenness that occurs in a formed image.

[0085] In order to prevent the above-mentioned image defects, the developing device 412 of the second embodiment is provided with a one-way clutch 220 shown in Fig. 9. Fig. 9 is a schematic view of the vicinity of the developing device 412 of the second embodiment as viewed from above. The one-way clutch 220 is provided on the rotation shaft 202a of the toner transport member 202 outside the developer casing 201 on the X-axis positive side, which is the side opposite to the side on which the drive transmission member 214 is disposed. One-way clutch 220 does not restrict toner transport member 202 from rotating in the first direction when drive transmission member 214 rotates in the first direction in the first operation. On the other hand, one-way clutch 220 restricts toner transport member 202 from rotating in the second direction when drive transmission member 214 rotates in the second direction in the second operation. One-way clutch 220 functions as a restricting member.

[0086] [Modification of the second embodiment] Next, an image forming apparatus 1 according to a modified example of the second embodiment will be described. In the following description, the same components as those in the image forming apparatus 1 according to the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0087] Image forming apparatus 1 of this modification includes detection unit 231, solenoid 232, and protrusion member 233 shown in Fig. 10 instead of one-way clutch 220. Fig. 10 is a block diagram showing a control function in the rotation restriction operation of toner conveying member 202 of this modification. Fig. 11 is a schematic view of the vicinity of developing device 412 of this modification from above. FIG. 12 is a schematic perspective view of the vicinity of the solenoid 232 and the protruding member 233. As shown in FIG.

[0088] The detection unit 231 detects the load applied to the drive motor 212, and thereby detects the rotational load of the toner transport member 202 via the drive transmission member 214. The rotational load of the toner transport member 202 is a load that the toner transport member 202 receives from the developer stored in the storage chamber 206. The detector 231 outputs the detected rotation load of the toner conveying member 202 to the controller 100 .

[0089] The solenoid 232 and the protruding member 233 are provided outside the developer housing 201 on the X-axis positive side, which is the side opposite to the side on which the drive transmission member 214 is disposed. The protruding member 233 is a plate-shaped member provided on the rotation shaft 202 a of the toner transport member 202 .

[0090] The solenoid 232 includes a movable part 232a that is displaceable in the Y-axis direction. Under the control of the control unit 100, the solenoid 232 displaces the movable part 232a so that the tip 232b of the movable part 232a is located at the first position B1 or the second position B2. 12, when the tip 232b of the movable part 232a is located at the first position B1, even if the toner conveying member 202 rotates, the tip 232b does not interfere with the protruding member 233. Therefore, the toner conveying member 202 is rotatable. In other words, the rotation of the toner conveying member 202 is not restricted. On the other hand, when the tip 232b of the movable part 232a is located at the second position B2, even if the toner conveying member 202 tries to rotate, the tip 232b interferes with the protruding member 233. Therefore, the toner conveying member 202 cannot rotate. In other words, the rotation of the toner conveying member 202 is restricted.

[0091] In this modification, the control unit 100 executes a rotation control process shown in FIG.

[0092] (Rotation control processing)

[0093] The control unit 100 acquires the rotation load of the toner conveying member 202 detected by the detection unit 231 during the rotation operation in the first direction (step S1). Next, the control unit 100 judges whether or not the rotation load of the toner conveying member 202 acquired in step S1 is greater than a predetermined value. The predetermined value is set in advance, and is, for example, 500 gf·cm.

[0094] A case where the rotation load of the toner transport member 202 is larger than the predetermined value (step S2; YES) will be described. In this case, the load that the toner transport member 202 receives from the developer when the drive transmission member 214 rotates in the second direction is larger than the transport force that transports the developer by the rotation of the toner transport member 202 in the second direction. In other words, this is the case where the toner transport member 202 does not rotate and remains stopped during the rotation operation in the second direction. In this case, the control unit 100 controls the solenoid 232 so that the tip 232b of the movable part 232a is located at the first position B1 in the rotational operation in the first direction and the rotational operation in the second direction (step S3), and ends the rotation control process.

[0095] On the other hand, a case where the rotation load of the toner transport member 202 is equal to or less than a predetermined value (step S2; NO) will be described. In this case, the load that the toner transport member 202 receives from the developer when the drive transmission member 214 rotates in the second direction is equal to or less than the transport force that transports the developer by the rotation of the toner transport member 202 in the second direction. In this case, the control unit 100 controls the solenoid 232 so that the tip 232b of the movable part 232a is located at the first position B1 during the rotation in the first direction, and the control unit 100 controls the solenoid 232 so that the tip 232b of the movable part 232a is located at the second position B2 during the rotation in the second direction (step S4), and ends the rotation control process.

[0096] That is, in the rotation control process, when the rotation load of toner conveying member 202 detected by detection unit 231 is greater than a predetermined value, control unit 100 does not regulate the rotation of toner conveying member 202. When the rotation load of toner conveying member 202 detected by detection unit 231 is equal to or less than a predetermined value, control unit 100 regulates the rotation of toner conveying member 202. Control unit 100 functions as a second control unit. Solenoid 232 and protrusion member 233 function as regulating members.

[0097] <7.Other> The developing device 412 may include a sealing member such as urethane foam or a soft sealing material to prevent leakage of the toner stored in the developer housing 201. The sealing member is a soft member that can fill gaps in the developer housing 201. When the toner transport member 202 is connected to the preventing member 208 via the sealing member, the vibration caused by the impact force F4 received by the toner transport member 202 is suppressed by the elasticity of the sealing member. For this reason, it is preferable that the toner transport member 202 is connected to the preventing member 208 via a rigid body. In this case, the vibration caused by the impact force F4 received by the toner transport member 202 is not easily suppressed and is efficiently transmitted to the preventing member 208. This makes it possible to efficiently crush the toner accumulated on the preventing member 208. The rigid body includes a plurality of rigid bodies fastened with a fastening member, or a plurality of rigid bodies bonded together with a hardening adhesive or the like.

[0098] In the second operation, when the drive transmission member 214 applies the impact force F4 to the toner conveying member 202, the impact generates a sound. The user can recognize that the second operation is being performed by the sound. However, when the surroundings of the image forming apparatus 1 are quiet, the user may be bothered by the sound. Therefore, in this embodiment, the drive transmission member 214 performs the second operation at the same timing as the charge cleaning operation performed in the image forming apparatus 1. The charge cleaning operation is an operation in which a charge cleaning member for cleaning the charge wire of the charging device 414 reciprocates in a direction along the charge wire. In the image forming apparatus 1, the control unit 100 performs the charge cleaning operation every time 3,000 sheets of A4 size paper are printed. The control unit 100 performs the charge cleaning operation every time a print job is completed. As a result, the sound generated in the second operation and the sound generated in the electrostatic cleaning operation occur simultaneously, so that the sound generated in the second operation of this embodiment is not conspicuous alone. That is, the second operation of the present embodiment is performed simultaneously with an operation different from the second operation performed by the image forming apparatus 1.

[0099] The drive transmission member 214 may perform the second operation during operation of a fan included in the image forming apparatus 1. The fan is a fan that prevents a temperature rise inside the image forming apparatus 1, and an ozone fan that performs a purification process by absorbing ozone generated inside the image forming apparatus 1 into a filter. As a result, the sound generated in the second operation and the sound generated by the operation of the fan occur simultaneously, so that the sound generated in the second operation does not stand out alone.

[0100] The drive transmission member 214 may perform the second operation during the operation of a post-processing device connected to the image forming apparatus 1. The post-processing device is a device that performs post-processing such as stapling, punching holes, sorting, saddle stitching, and folding in three on paper after image formation. As a result, the sound generated during the second operation and the sound generated by the operation of the post-processing device are generated simultaneously, so that the sound generated during the second operation alone is not noticeable.

[0101] <8. Effects> As described above, the image forming apparatus 1 according to this embodiment includes a developing device 412 that develops a latent image by adhering toner to the latent image via a toner carrier (developing roller 204) arranged opposite the latent image carrier (photosensitive drum 413) on which the latent image is formed, thereby making the latent image visible. The developing device 412 includes a drive transmission member 214 that transmits a drive force to a toner transport member 202 that transports the toner. The drive transmission member 214 switches between a first operation of transmitting a drive force for transporting the toner to the toner transport member 202 and a second operation of vibrating a prevention member 208 provided in the developing device 412 to prevent the toner from scattering. As a result, the prevention member 208 can be vibrated by the drive transmission member 214, which is a member that transmits the drive force for transporting the toner to the toner transport member 202. In other words, there is no need for a dedicated part for vibrating the prevention member 208. Therefore, it is possible to suppress image defects caused by toner accumulated in the developing device 412 while suppressing an increase in size or cost of the device.

[0102] The image forming apparatus 1 according to this embodiment includes a first control unit (control unit 100) that switches the rotation direction of the drive transmission member 214 to cause the drive transmission member 214 to switch between a first operation and a second operation. This makes it possible to easily switch between the first operation and the second operation performed by the drive transmission member 214 by switching the rotation direction of the drive transmission member 214.

[0103] In the image forming apparatus 1 according to this embodiment, the first control unit (control unit 100) rotates the drive transmission member 214 in a first direction in a state in which the engaged portion 214a of the drive transmission member 214 is engaged with the engaging portion 202e of the toner transport member 202. As a result, the first control unit causes the drive transmission member 214 to transmit a drive force larger than the rotational load of the toner transport member 202 to the toner transport member 202 as a first operation, thereby rotating the toner transport member 202 in the first direction to transport the toner. The first control unit rotates the drive transmission member 214 in a second direction that is opposite to the first direction, and causes the drive transmission member 214 to perform a second operation while the rotation of the toner transport member 202 is stopped. This makes it possible to easily switch between the first operation and the second operation performed by the drive transmission member 214 simply by switching the rotation direction of the drive transmission member 214.

[0104] The image forming apparatus 1 according to this embodiment is provided with a regulating member (one-way clutch 220, or solenoid 232 and protrusion member 233) that regulates the toner transport member 202 not to rotate in the second direction when the drive transmission member 214 rotates in the second direction. This makes it possible to suppress the occurrence of image defects such as uneven screw pitch.

[0105] In the image forming apparatus 1 according to this embodiment, the drive transmission member 214 transmits a driving force to the toner conveying member 202 via the engaged portion 214a of the drive transmission member 214, which is in an engaged state in the first operation, and the engagement portion 202e of the toner conveying member 202. This makes it possible to transmit the driving force for conveying the toner to the toner conveying member 202 with a simple configuration.

[0106] In the image forming apparatus 1 according to this embodiment, the drive transmission member 214 is displaceable along the axial direction of the toner transport member 202. The drive transmission member 214 performs a second operation when displacing from a position in which the engaged portion 214a and the engaging portion 202e are disengaged to a position in which the engaged portion 214a and the engaging portion 202e are engaged with each other. This makes it possible to vibrate the prevention member 208 with a simple structure.

[0107] In the image forming apparatus 1 according to this embodiment, the developing device 412 includes an elastic member 213. The drive transmission member 214 uses the elastic force of the elastic member 213 to perform the second operation. This makes it possible to vibrate the prevention member 208 with a simple structure.

[0108] Image forming apparatus 1 according to the present embodiment includes detection unit 231 that detects the rotational load of toner transport member 202. Image forming apparatus 1 includes a second control unit (control unit 100) that does not restrict the rotation of toner transport member 202 when the rotational load detected by detection unit 231 is greater than a predetermined value, and restricts the rotation of toner transport member 202 when the rotational load is equal to or less than the predetermined value. This makes it possible to suppress the occurrence of image defects such as uneven screw pitch.

[0109] In the image forming apparatus 1 according to this embodiment, the toner transport member 202 is connected to the prevention member 208 via a rigid body. As a result, the vibration caused by the impact force F4 received by the toner conveying member 202 is not easily suppressed, and is efficiently transmitted to the preventing member 208. As a result, the toner accumulated on the preventing member 208 can be efficiently crushed.

[0110] In the image forming apparatus 1 according to the present embodiment, the second operation is performed simultaneously with an operation different from the second operation performed in the image forming apparatus 1. This prevents only the sound generated during the second operation from being noticeable when the surroundings of the image forming apparatus 1 are quiet.

[0111] The above is a specific explanation based on an embodiment of the present invention, but the detailed configuration and detailed operation of each device constituting the image forming apparatus 1 can also be modified as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, the developing device 412 is of a two-component developing type, but the developing device 412 may be of a single-component developing type.

[0112] In the above description, an example has been disclosed in which a HDD or a non-volatile semiconductor memory is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to this example. As other computer-readable media, a portable recording medium such as a CD-ROM can be applied. Furthermore, a carrier wave can be applied as a medium for providing data of the program according to the present invention via a communication line. [Explanation of symbols]

[0113] 1. Image forming device 100 control unit (first control unit, second control unit) 10 Image reading unit 11 Automatic document feeder 12 Original image scanning device 12a CCD sensor 20 Operation display section 21 Display section 22 Control section 30 Image processing section 40 Image forming section 41, 41C, 41K, 41M, 41Y Image forming unit 411 Exposure equipment 412 Developing device 413 Photoconductor drum (latent image carrier) 414 Charging device 415 Drum cleaning device 42 Intermediate transfer unit 421 Intermediate transfer belt 422 Primary transfer roller 423 Support Roller 423A Roller 423B Backup roller 424 Secondary transfer roller 426 Belt cleaning device 50 Paper transport section 51 Paper feed section 51a, 51b, 51c Paper feed tray unit 52 Paper output section 52a Paper ejection roller 53 Conveying path section Registration roller pair 60 Fixing unit 70 Storage section 80 Communications Department 201 Developer housing 201a Exterior wall 202 Toner transport member 202a Rotating shaft 202b End 202c Screw member 202d Engagement member 202e Engagement part 202f end 202g Opposite surface 203 Toner supply member 203a Supply screw 203b Reverse winding screw 203c Discharge screw 204 Developing roller (toner carrier) 205 Bulkhead 205a,205b opening Containment Room 206 206a Supply port Containment Room 207 207a Outlet 208 Prevention material 209 Suction part 209a Duct 209b Suction port 210 Drive mechanism 211 Bearings 212 Drive motor 213 Elastic Members 214 Drive transmission member 214a Engaged part 214b Parallel part 214c Slope 214d Opposite surface 214e Through hole 214f Rotation axis 215 Inner wall surface 220 One-way clutch (regulating member) 231 Detection Unit 232 Solenoid (regulating member) 233 Protruding parts (regulating parts) N Development Nip S paper

Claims

1. a developing device that develops a latent image by attaching toner to the latent image via a toner carrier disposed opposite a latent image carrier on which the latent image is formed; the developing device includes a drive force transmission member that transmits a drive force to a toner transport member that transports the toner, An image forming apparatus, wherein the drive transmission member switches between a first operation of transmitting the drive force for transporting the toner to the toner transport member and a second operation of vibrating a prevention member provided in the developing device that prevents the toner from scattering.

2. The image forming apparatus according to claim 1 , further comprising a first control unit that switches a rotation direction of the drive transmission member to switch between the first operation and the second operation of the drive transmission member.

3. The first control unit is a driving force transmission member that is greater than a rotational load of the toner transport member is transmitted to the toner transport member as the first operation by rotating the driving force transmission member in a first direction while an engaged portion of the driving force transmission member is engaged with an engaging portion of the toner transport member, and the toner is transported by rotating the toner transport member in the first direction; 3. The image forming apparatus according to claim 2, wherein the drive transmission member is rotated in a second direction that is opposite to the first direction, and the drive transmission member is caused to perform the second operation while the rotation of the toner transport member is stopped.

4. The image forming apparatus according to claim 3 , further comprising a regulating member that regulates the toner transport member so as not to rotate in the second direction when the drive transmission member rotates in the second direction.

5. 2 . The image forming apparatus according to claim 1 , wherein the drive transmission member transmits the driving force to the toner transport member via an engaged portion of the drive transmission member that is in an engaged state in the first operation and an engaging portion of the toner transport member.

6. 6. The image forming apparatus of claim 5, wherein the drive transmission member is displaceable along the axial direction of the toner transport member, and performs the second operation when displaced from a position in which the engaged portion and the engaging portion are disengaged to a position in which the engaged portion and the engaging portion are engaged.

7. The developing device includes an elastic member, The image forming apparatus according to claim 1 , wherein the drive transmission member performs the second movement by utilizing an elastic force of the elastic member.

8. A detection unit that detects a rotation load of the toner transport member; a second control unit that does not regulate the rotation of the toner transport member when the rotation load detected by the detection unit is greater than a predetermined value, and regulates the rotation of the toner transport member when the rotation load is equal to or smaller than the predetermined value; The image forming apparatus according to claim 1 .

9. The image forming apparatus according to claim 1 , wherein the toner transport member is connected to the prevention member via a rigid body.

10. The image forming apparatus according to claim 1 , wherein the second operation is performed simultaneously with an operation different from the second operation performed in the image forming apparatus.

Images