Image forming apparatus

Abstract

To prevent a failure in supplying toner from a toner cartridge to a developing unit.SOLUTION: An image forming apparatus has: developing units that develop images with developer; a rotary that is rotatably supported and stores the developing units and cartridges storing the developer to be supplied to the developing units; a driving section that rotates the rotary; and a control section that controls the driving section. The control section controls the driving section to execute acceleration and deceleration of the rotation of the rotary at least twice in a period during which the developing units do not develop the images.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material. [Background technology]

[0002] In electrophotographic image forming apparatuses, a rotary development system is known in which a color image is formed by rotating a rotary equipped with multiple development units each having a toner container and a development container. The image forming apparatus is described in which, when the development units are tilted at a predetermined angle by the rotation of the rotary, toner falls from the toner container into the development container, and a predetermined amount of toner is supplied to the development container.

[0003] In an image forming apparatus equipped with such a rotary development system, when forming a full-color image, the rotary rotates a predetermined angle each time one page of image for each color is developed, and multiple transfer is performed. Therefore, the rotary makes one rotation to form one page of color image, and toner is supplied from the toner container to the developing container within a predetermined rotation range during that rotation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-008794 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a toner container is left unused for a long period of time, the toner inside the container may adhere to the container walls or to each other, making it difficult to supply to the developer container. This toner adhesion may not be eliminated during normal image formation, and toner adhesion is particularly likely to occur in high-temperature, high-humidity environments. When toner adhesion occurs, the toner container may be replaced with the toner remaining in the toner container rather than being supplied to the developer container, resulting in wasted toner. To address this issue, providing a stirring member for stirring the toner inside the toner container can loosen the toner adhesion, but this results in a complex configuration with many components constituting the image forming apparatus including the toner container. Therefore, in order to reduce the number of components, size, and cost of the image forming apparatus, it is desirable to suppress toner adhesion without a stirring member and prevent toner waste.

[0006] The present invention has been made in consideration of the above-mentioned conventional examples, and aims to suppress toner adhesion without using a stirring member in an image forming apparatus using a toner supply system that supplies toner from a toner container to a developing container, and to consume toner in the toner container without waste. [Means for solving the problem]

[0007] In order to achieve the above object, according to one aspect of the present invention, there is provided an image forming apparatus in which a first cartridge containing a first developer and a second cartridge containing a second developer are detachably mountable, the image forming apparatus comprising: a first developing unit including a first container that contains the first developer supplied from the first cartridge, and a first developing member that develops an electrostatic latent image formed on a photosensitive member using the first developer contained in the first container; a second developing unit including a second container that contains the second developer supplied from the second cartridge, and a second developing member that develops the electrostatic latent image formed on the photosensitive member using the second developer contained in the second container; a rotatable rotary including the first developing unit and the second developing unit; a drive unit that drives the rotary so that the rotary rotates; a control unit that controls the drive unit; and the first developer in the first cartridge is supplied to the first container by being discharged from a first discharge opening formed in the first cartridge to a first receiving opening formed in the first container, the rotary has a first supplying position in which a direction from the first discharge opening to the first receiving opening has a vertical downward component, and a first developing position in which the first developing member is capable of developing on the photosensitive member, the control unit controls the drive unit so that the rotary performs an acceleration / deceleration operation of accelerating and then decelerating at least twice or more during a period in which the rotary rotates from the first supply position to the first developing position. An image forming apparatus characterized by the above features is provided.

[0008] According to another aspect of the present invention, there is provided a developing unit for developing an image with a developer; a rotatably supported rotary that accommodates the developing unit and a cartridge that accommodates a developer to be supplied to the developing unit; a vibration applying unit that can come into contact with and move away from the rotary and applies vibration to the rotary; a control unit that controls the vibration of the vibration unit, The control unit controls the vibration unit to apply vibration to the rotary during a period when the development unit is not developing an image. An image forming apparatus characterized by the above features is provided. [Effects of the Invention]

[0009] According to the present invention, it is possible to break up toner clumps in an image forming apparatus without using an agitating member, and it is possible to consume toner in a toner container without waste. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment. [Figure 2] Schematic cross-sectional view of a rotary body and its peripheral members according to the first embodiment. [Figure 3] Schematic cross-sectional view illustrating the attachment and detachment of the toner cartridge to and from the rotary body 90 according to the first embodiment. [Figure 4] Schematic cross-sectional view of a developing unit, a toner cartridge, and a tray according to the first embodiment. [Figure 5] FIG. 1 is a diagram showing a control unit according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing the flow of rotary rotation control during image formation according to the first embodiment. [Figure 7] Schematic diagram showing the attitude of the toner cartridge at the timing of toner replenishment during image formation according to the first embodiment. [Figure 8] FIG. 10 is a diagram showing the flow of rotary rotation control in a rotary acceleration / deceleration operation mode according to the first embodiment. [Figure 9] Schematic diagram showing the orientation of the toner cartridge in the rotary operation mode according to the first embodiment. [Figure 10] FIG. 10 is a diagram showing the flow of rotary rotation control in a rotary operation mode according to the second embodiment. [Figure 11] Schematic diagram showing the orientation of the toner cartridge in the rotary operation mode according to the second embodiment. [Figure 12] FIG. 10 is a diagram showing the flow of rotary rotation control in a rotary operation mode according to the third embodiment. [Figure 13] FIG. 10 is a diagram showing the flow of rotary rotation control in a rotary operation mode according to the fourth embodiment. [Figure 14] FIG. 10 is a diagram showing the flow of control of rotary rotation and vibration actuators in a rotary operation mode according to a modification of the fourth embodiment. [Figure 15] Block diagram showing the configuration of the control unit [Figure 16] Diagram showing the tray insertion / removal mechanism [Figure 17] Flowchart showing the control procedure for accelerating and decelerating the rotary DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] [Embodiment 1] An image forming apparatus 1 according to a first embodiment of the present invention will be described using Figures 1 to 9. In the following description and in each drawing, the vertical direction when the image forming apparatus 1 is installed on a horizontal surface is referred to as the Z direction. The direction perpendicular to the Z direction, which is the direction of a rotation axis 90C of a rotary main body 90 (described later) (the direction of the rotary's rotation axis), is referred to as the Y direction. The direction perpendicular to both the Z direction and the Y direction is referred to as the X direction. Furthermore, as necessary, the directions of the arrows X, Y, and Z shown in each drawing will be represented as the +X side, +Y side, and +Z side, respectively, and the opposite sides will be represented as the -X side, -Y side, and -Z side, respectively.

[0013] (Overall configuration of image forming apparatus) First, the overall configuration of the image forming apparatus 1 will be described. The image forming apparatus 1 is a laser printer that forms an image on a sheet S by electrophotography. More specifically, the image forming apparatus 1 is a rotary development color laser printer equipped with a rotary main body 90 having four development units 50y, 50m, 50c, and 50k. The subscripts attached to the development units 50y, 50m, 50c, and 50k indicate the toner colors: y indicates yellow, m indicates magenta, c indicates cyan, and k indicates black, and a full-color image is formed by overlaying each color.

[0014] The schematic configuration and image forming operation of the image forming apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the cross-sectional configuration of the image forming apparatus 1.

[0015] The image forming device 1 includes a main body and three detachable toner cartridges 70y, 70m, 70c, and 70k. The toner cartridge 70 contains toner, which is a developer. Here, the toner cartridge 70 is sometimes simply referred to as a cartridge. A toner cartridge containing a first developer, which is a developer of a specific color, is sometimes referred to as a first cartridge, and a toner cartridge containing a developer in a different mount from the first developer is sometimes referred to as a second cartridge. The image forming device 1 includes a cylindrical photosensitive drum 2, which serves as an image carrier or photosensitive member that carries the toner, which is a developer, and forms an electrostatic latent image. The electrostatic latent image is formed on the photosensitive drum 2. A charging roller 3, which serves as a charging means, a scanner 4, which serves as an exposure means, and a photosensitive drum cleaning unit 6, which serves as a cleaning means, are arranged around the photosensitive drum 2. The surface of the photosensitive drum 2 is uniformly charged by the charging roller 3, and the scanner 4 irradiates the surface with laser light corresponding to image information, forming an electrostatic latent image. The image forming apparatus 1 also includes developing units 50y, 50m, 50c, and 50k that develop (visualize) the electrostatic latent image formed on the surface of the photosensitive drum 2 into a toner image using toner of the corresponding color. The developing units 50y, 50m, 50c, and 50k each develop the electrostatic latent image formed on the photosensitive drum 2 using yellow toner, magenta toner, cyan toner, or black toner. The developing unit 50y includes a developing roller 51y and a supply roller 52y. The developing roller 51y is a developer carrier that carries and rotates to carry toner as a developer and supplies the toner to the photosensitive drum 2. The supply roller 52y is disposed in contact with the developing roller 51y and is a supply member that supplies toner to the developing roller 51y. The other developing units 50m, 50c, and 50k also include similar developing rollers 51m, 51c, and 51k and supply rollers 52m, 52c, and 52k. However, in FIG. 1, the developing roller 51y and the shared roller 52y are shown as representatives, and the reference numerals for the developing units 50m, 50c, and 50k of the other colors are not shown. Furthermore, the image forming apparatus 1 includes a sheet storage unit 300, a pickup roller 310, a feed roller 311, a separation roller 312, a pair of conveying rollers 320, a primary transfer roller 11, a secondary transfer roller 12, a fixing device 40, and an intermediate transfer unit 10. The pickup roller 310 is a feeding unit that feeds the sheet S, and the feed roller 311 and the separation roller 312 are a separation and conveying unit that separates and conveys the sheets S one by one by friction. The toner image formed on the photosensitive drum 2 is primarily transferred from the photosensitive drum 2 to the intermediate transfer belt 10a by the primary transfer roller 11 disposed inside the intermediate transfer belt 10a. The secondary transfer roller 12 is a transfer unit that transfers the toner image from the intermediate transfer belt 10a to the sheet S. After the toner image is transferred onto the sheet S, the cleaning device 13 removes the toner remaining on the intermediate transfer belt 10a.

[0016] The developing unit 50 that develops the electrostatic latent image on the photosensitive drum 2 with the first developer may be called the first developing unit, and the developing unit 50 that develops the electrostatic latent image with the second developer may be called the second developing unit. Furthermore, the developing roller 51 provided in the first developing unit 50 may be called the first developing roller, and the developing roller 51 provided in the second developing unit 50 may be called the second developing roller.

[0017] (Rotary configuration) The configuration of the rotary body 90 will be described using Figures 1 to 4. As shown in Figure 1, the rotary body 90 has developing units 50y, 50m, 50c, and 50k, and toner cartridges 70y, 70m, 70c, and 70k corresponding to each developing unit 50 are attached. Yellow toner, magenta toner, cyan toner, and black toner are stored inside the toner cartridges 70y, 70m, 70c, and 70k, respectively, as toner to be replenished to the developing units 50y, 50m, 50c, and 50k. In addition, the rotary body 90 is attached with trays 80y, 80m, 80c, and 80k that detachably hold the toner cartridges 70y to 70k. The operation of attaching and detaching the toner cartridges 70 to and from the trays 80 will be described later.

[0018] The rotary body 90 is supported rotatably around a rotation axis 90C in the Y-axis direction. By rotating around the rotation axis 90C, the rotary body 90 can position one of the developing rollers 51y, 51m, 51c, and 51k facing the photosensitive drum 2. The rotary body 90 is also supported rotatably around a swing axis 91 and is constantly biased counterclockwise so that the developing roller 51 contacts the photosensitive drum 2. This causes the developing roller 51 to abut against the photosensitive drum 2, forming a development nip. Note that the position of each developing unit 50 changes as the rotary 90 rotates. In this embodiment, the amount by which the rotary 90 rotates is referred to as a rotation angle. In the ZX plane of FIG. 1, the rotation axis 90C is used as the origin, and objects included in or attached to the rotary 90 change position as the rotary 90 rotates. This change in position is represented in polar coordinates by a change in the deflection angle alone. The position of the rotary 90, expressed as an angle with respect to the rotation axis 90C as the origin, is called the attitude, rotation phase, rotary phase, or simply phase of the rotary 90.

[0019] FIG. 2 is a cross-sectional schematic diagram of the rotary body 90 and peripheral components, illustrating the contact and separation states of the photosensitive drum 2 and the developing roller 51k. FIG. 2(a) shows the black developing position in which the developing roller 51k contacts the photosensitive drum 2, forming a developing nip at the contact point. The developing position in this embodiment is a position in which, with the image forming apparatus 1 installed horizontally, the angle between a line drawn from the rotation axis 90C of the rotary body 90 to the developing nip and the horizontal is 20°. In other words, the developing position can also be described as a position in which the angle between the plane including the rotation axis 90C of the rotary body 90 and the developing nip and the installation surface of the image forming apparatus 1 is 20°. The installation surface here refers to a plane including the point where the image forming apparatus 1 is stably placed on the ground, and may also be referred to as the bottom surface of the image forming apparatus 1. In the following description, the term "horizontal" is used, assuming that the installation surface of the image forming apparatus 1 is horizontal. Therefore, the term "horizontal" can be rephrased as "parallel to the installation surface" or "a surface parallel to the installation surface", for example.

[0020] The posture in which the developing roller 51y faces the photosensitive drum 2 is called the yellow developing posture, the posture in which the developing roller 51m faces the photosensitive drum 2 is called the magenta developing posture, and the posture in which the developing roller 51c faces the photosensitive drum 2 is called the cyan developing posture.

[0021] On the other hand, the rotary body 90 can also be in a separated state in which the developing rollers 51y, 51m, 51c, and 51k are not in contact with the photosensitive drum 2. As shown in Figure 2(b), the cam 96 rotates to come into contact with the frame of the rotary body 90, and rotates the rotary body 90 around the swing shaft 91 in the clockwise direction indicated by the dashed arrow, thereby separating the photosensitive drum 2 and the developing roller 51k.

[0022] When waiting for image formation to be performed, the rotary body 90 assumes a standby position in which the photosensitive drum 2 and the developing roller 51 are spaced apart, and the photosensitive drum 2 is positioned between the developing rollers 51c and 51k, as shown in Figure 2(c).

[0023] When the user replaces the toner cartridge 70, the rotary body 90 takes the replacement position. The replacement position for the black toner cartridge 70k is shown in Figure 2(d). In this replacement position for the black toner cartridge 70k, the black toner cartridge 70k is positioned approximately horizontally.

[0024] (Installing and removing toner cartridges) The attachment and detachment of the toner cartridge 70k to and from the rotary body 90 will be described with reference to FIG. 3. The image forming apparatus 1 has an opening 16a provided on the +X side surface of the housing 16. As shown in FIG. 3(a), the toner cartridge 70k is stopped in the black toner cartridge 70k replacement position of the rotary body 90, which is a position facing the opening 16a and the door 14 (see FIG. 1), and is supported by the tray 80k. From this position, as shown in FIG. 3(b), the door 14 opens, and the tray 80k slides through the opening 16a to the outside of the rotary body 90. In this state, the toner cartridge 70k becomes detachable from the tray 80k, i.e., the rotary body 90, and the user can replace the toner cartridge 70k.

[0025] 4 is a schematic diagram of the developing unit, toner cartridge, and tray according to this embodiment. The toner cartridge 70 has a toner frame 71. The toner frame 71 has a toner storage section 71a that stores toner, and a discharge opening 71b that communicates with the toner storage section 71a.

[0026] The developing unit 50 has a developing frame (storage frame) 53. The developing frame 53 has a developing-side storage portion 53a and a receiving opening 53b that communicates with the developing-side storage portion (toner supply chamber) 53a. As mentioned above, the developing unit 50 has a developing roller 51, a supply roller 52, etc., but these members are omitted in Figure 4. The developing-side storage portion 53 of the first developing unit may be referred to as the first storage portion, and the developing-side storage portion 53 of the second developing unit may be referred to as the second storage portion, etc.

[0027] The toner cartridge 70 is movable relative to the developing frame 53 between an attached position and a retracted position retracted from the attached position. The attached position is a position where the toner cartridge 70 is attached to the tray 80 and housed in the rotary 90, as shown in FIG. 3(a). The retracted position is a position where the toner cartridge 70 is ejected to the outside of the rotary 90 while still placed on the tray 80, as shown in FIG. 3(b). When the toner cartridge 70 is attached to the developing frame 53, the discharge opening 71b faces the receiving opening 53b. That is, the toner storage portion 71a of the toner cartridge 70 and the developer-side storage portion 53a of the developing unit 50 communicate with each other through a communication portion 60 (indicated by a broken line) formed by the discharge opening 71b and the receiving opening 53b. As will be described in detail later, when toner is replenished from the toner cartridge 70 to the developing unit 50, the communication portion 60 is oriented vertically downward (in the -Z direction) from the horizontal.

[0028] Furthermore, the developing unit 50 preferably has a sealing member 55 that covers the receiving opening 53b to prevent toner from the developing-side accommodating portion from flowing back into the toner accommodating portion of the toner cartridge 70. This sealing member 55 is configured to be able to open and close by rotating around one end as a pivot due to gravity acting on the sealing member 55. As shown in FIG. 4(a), when the direction (indicated by arrow 401) from the discharge opening 71b of the communicating portion 60 to the receiving opening 53b is vertically downward (-Z direction) rather than horizontal, the sealing member 55 opens so as not to interfere with toner replenishment. On the other hand, when the direction from the discharge opening 71b of the communicating portion 60 to the receiving opening 53b is vertically upward (+Z direction) rather than horizontal, the sealing member 55 closes to fulfill its sealing role.

[0029] (Control unit and drive unit) 15, the image forming apparatus 1 has a control unit 31 and motors M1, M2, and M3 as drive sources (or drive units) controlled by the control unit 31. The control unit 31 includes a memory 312 storing programs and a CPU 311 (or processor), and the CPU 311 executes the programs stored in the memory 312 to implement control procedures for the motors and the like. As will be described later, the motor M1 supplies a drive force for rotating the rotary body 90 around the rotation axis 90C in accordance with the control of the control unit 31.

[0030] The image forming apparatus 1 also has a drive device 98 including a motor M2 and a transmission device. The transmission device includes drive racks 15L and 15R as drive gears, and a transmission unit 15t, which will be described later. The driving force of the motor M2 is transmitted to the drive racks 15L and 15R by the transmission unit 15t. In other words, the motor M2 is configured to drive the drive racks 15L and 15R, and moves the trays 80y, 80m, 80c, and 80k to insert into or eject from the rotary body 90 via the drive racks 15L and 15R. The drive racks 15L and 15R are also collectively referred to as drive racks 15.

[0031] Motor M3 drives components other than those driven by motors M1 and M2, such as the photosensitive drum 2, developing units 50y, 50m, 50c, and 50k, pickup roller 310, feed roller 311, conveying roller pair 320, secondary transfer roller 12, intermediate transfer belt 10a, and fixing device 40.

[0032] The components driven by motors M1, M2, and M3 can be changed as needed. Also, the functions of any two or all three of motors M1, M2, and M3 can be combined into one motor. Alternatively, drive sources other than motors M1, M2, and M3 may be added.

[0033] (Toner cartridge replacement operation) Figure 16 shows a cross section of the rotary 90 and its surroundings when replacing a toner cartridge. As shown in Figure 16(b), when replacing a toner cartridge, the user installs or removes the toner cartridge 70k from the tray 80, so the entire toner cartridge 70k protrudes from the front of the image forming apparatus 1. A toner tray storage detection sensor is also provided, making it possible to determine whether the tray 80k has been inserted and storage has been completed. Note that while the toner cartridge 70k will be described as an example, the same applies to the other toner cartridges.

[0034] As an example of a drive transmission mechanism, the mechanism used in this embodiment has a configuration in which a rack is arranged along the sliding direction of the tray 80, and a gear meshed with the rack is driven to rotate, thereby moving the tray in and out of the rotary from the replacement position or the retracted position. This configuration will be described with reference to FIG.

[0035] (Tray insertion / removal drive configuration) 16(a) and 16(b), the tray insertion / removal operation of sliding the tray 80k from inside the rotary 90 (the installation position where the toner cartridge 70k is installed in the development unit 50k) to the retracted position outside the rotary 90 will be described. The tray 80k insertion / removal operation is performed by the motor M2, which is a drive source, the drive rack 15, the rack gear 94k, and the rack portion 821k. First, the drive force transmitted by the motor M2 causes the drive rack 15 to slide upward in the image forming apparatus main body 1 and transmits the drive to the rack gear 94k. The rack gear 94k rotates counterclockwise and transmits the drive to the rack portion 821k, causing the tray 80k to slide from the installation position where the toner cartridge 70k is installed in the development unit 50k to the retracted position outside the rotary 90. The door 14 may open in conjunction with this operation or by being pushed by the tray 80.

[0036] Furthermore, after replacing the toner cartridge, the operation of sliding the tray 80k into the rotary 90 can be performed by rotating the motor M2 in the opposite direction to that used to slide the tray 80k out of the rotary 90. In this case, the drive rack 15 slides downward in the image forming apparatus 1, thereby drawing the tray 80k into the rotary 90. Note that "inside the rotary 90" refers to the position where the toner cartridge 70k is attached to the developing unit 50k. The door 14 may close in conjunction with this operation, or may be biased in the closing direction by a spring or the like, or may be closed manually.

[0037] As described above, the toner cartridge 70 can be moved relative to the developing frame 53 between the mounted position and a retracted position retracted from the mounted position. The toner cartridge 70 can be replaced when it is in the retracted position. In the retracted position, the discharge opening 712 of the toner cartridge 70 opens upward relative to the toner cartridge 70. In this state, the receiving opening 532 of the developing unit 50, to which developer is supplied from the mounted toner cartridge 70, opens downward relative to the developing unit 50. The tray 80 carrying the toner cartridge 70 in the retracted position is moved into the rotary 90, and the toner cartridge 70 moves to the mounted position. In this state, the rotary 90 is rotated to the development position where the developing roller 51 of the target developing unit contacts the photosensitive drum 2 for development.

[0038] The discharge opening 712 of the first cartridge may be referred to as the first discharge opening, the discharge opening 712 of the second cartridge as the second discharge opening, the receiving opening 532 of the first developing unit as the first receiving opening, and the receiving opening 532 of the second developing unit as the second receiving opening. Furthermore, the position of the rotary 90 in which the direction from the first discharge opening of the first cartridge to the first receiving opening of the first developing unit has a vertically downward component may be referred to as the first supply position. Furthermore, the position of the rotary 90 in which the first developing member of the first developing unit is capable of developing on the photosensitive drum 2 may be referred to as the first developing position.

[0039] (Video Controller) The video controller 30 serving as an image processing unit will be described with reference to the diagram shown in Fig. 5. The video controller 30 includes devices such as a host interface unit 302, ROM 304, RAM 305, and CPU 306, which are interconnected via a CPU bus 301. The CPU bus 301 includes address, data, and control buses, and is also connected to RAM 307, a developing unit toner remaining amount detection sensor 308, and a pixel count unit 309. The host interface unit 302 has a function of establishing a bidirectional communication connection with a data transmission device such as a host computer via a network.

[0040] ROM 304 stores control program code for executing the processes described below. RAM 305 is a memory for storing temporary buffer areas and various processing statuses. RAM 305 also stores the remaining toner amount in the development unit 50 for each color. CPU 306 controls each device connected to CPU bus 301 based on the control program code stored in ROM 304. RAM 307 is a memory provided in the toner cartridge 70 for each color, and stores the remaining toner amount in the toner cartridge 70. Development unit remaining toner amount detection sensor 308 is a sensor that detects whether the remaining toner amount in the development unit 50 in the development position is equal to or greater than a predetermined amount. Pixel counting unit 309 counts the number of image dots in image data developed with toner of each color.

[0041] In this embodiment, the video controller 30 and the control unit 31 are described as separate entities, but either one may perform the functions of both. In that case, for example, the control unit 30 can detect and manage the amount of toner remaining in the toner cartridge 70 or the developing unit 50.

[0042] (Toner remaining amount detection) The method of detecting the remaining toner amount will now be described. The RAM 305 stores the remaining toner amount in the development unit 50 of each color, and when the development unit 50 is new, an initial value corresponding to the initial amount of toner in the development unit 50 is stored. The initial value of the toner amount in the development unit 50 is stored in advance in the ROM 304. Meanwhile, the RAM 307 provided in each of the toner cartridges 70y, 70m, 70c, and 70k stores the remaining toner amount in the toner cartridge 70 of each color. When the toner cartridge 70 is new, an initial value corresponding to the initial (new) amount of toner in the toner cartridge 70 is stored.

[0043] During image formation, the current remaining amount of toner is calculated by subtracting the amount of toner consumed according to the count of the number of image dots detected by the pixel counting unit 309 from the remaining amount of toner in the developing unit 50, and the remaining amount of toner in the developing unit 50 stored in the RAM 305 is updated.

[0044] When the rotary body 90 rotates, toner is replenished from the toner cartridge 70 to the developing unit 50. When the amount of toner remaining in the developing unit 50 is large, the amount of toner that can be replenished decreases, so the amount of toner replenishment is determined according to the amount of toner remaining in the developing unit 50. A value determined in advance through experiments to determine the amount of toner replenishment according to the amount of toner remaining in the developing unit 50 is stored in ROM 304. When the rotary body 90 rotates, this amount of toner replenishment is added to the amount of toner remaining in the developing unit 50 to determine the current amount of toner remaining, and the amount of toner remaining in the developing unit 50 stored in RAM 305 is updated. At the same time, the amount of toner replenishment is subtracted from the amount of toner remaining in the toner cartridge 70 to determine the current amount of toner remaining in the toner cartridge 70, and the amount of toner remaining in the toner cartridge 70 stored in RAM 307 is updated.

[0045] Before the remaining amount of toner in the toner cartridge 70 reaches zero, a message to that effect is displayed on a liquid crystal panel (not shown), urging the user to replace the toner cartridge 70.

[0046] Furthermore, regardless of the amount of toner remaining in the toner cartridge 70, if the amount of toner remaining in the developing unit 50 becomes too low, the developing roller 51 may rotate and be damaged when the toner is depleted. To prevent this, a developing unit toner remaining amount detection sensor (not shown) is provided. The developing unit toner remaining amount detection sensor is located in a position where it can detect when the amount of toner remaining in the developing unit 50 falls below 50%, and when it detects this, a message to that effect is displayed on a liquid crystal panel (not shown) to prompt the user to replace the toner cartridge 70.

[0047] (Image formation operation) The image forming operation in this embodiment will now be described. When the video controller 30 receives image information from an external device (not shown) such as a host computer, it sends a print signal, and the image forming operation begins. First, in the standby position, the photosensitive drum 2 is rotated in the direction of arrow R1 (counterclockwise) in FIG. 1 in synchronization with the rotation of the intermediate transfer belt 10a. Then, the surface of the photosensitive drum 2 is uniformly charged by the charging roller 3.

[0048] When a color image is formed on the sheet S, the rotary body 90 rotates in the direction of arrow R2 (clockwise) in Figure 1 while supporting the developing units 50y, 50m, 50c, and 50k. Then, the electrophotographic process is repeatedly performed while the developing rollers 51y, 51m, 51c, and 51k are moved one by one to the developing position.

[0049] First, the scanner 4 irradiates the photosensitive drum 2 with laser light based on image data corresponding to a yellow image, forming an electrostatic latent image corresponding to the yellow image on the surface of the photosensitive drum 2. In parallel with the formation of this electrostatic latent image, the control unit 31 and a DC brush motor M1 (not shown) control the rotation of the rotary body 90.

[0050] Figure 6 is a diagram showing a time series of the flow of drive control of the rotary body 90. Figure 6(a) is a diagram showing the rotary rotation speed when drive control is performed on the rotary body 90, and Figure 6(b) is a diagram showing the rotary rotation acceleration when drive control is performed on the rotary body 90.

[0051] First, the rotary rotates clockwise around the rotation axis 90C from the standby position shown in FIG. 2(c) (Timing A in FIG. 6) to move to the yellow developing position, while the cam 96 rotates to swing the rotary body 90 counterclockwise around the swing shaft 91. This causes the developing roller 51y to come into contact with the photosensitive drum 2 as shown in FIG. 2(a) (Timing B in FIG. 6). Note that FIG. 2(a) shows the case where the toner to be developed is black.

[0052] The rotary rotation speed (angular velocity) is controlled to reach the target speed in a predetermined time Δt1 as shown in Figure 6(a). Specifically, the rotary rotation speed is increased to 240° / sec in 100 msec. The rotation acceleration (angular acceleration) at this time is as shown in Figure 6(b), with a maximum value of 2400° / sec. 2 (shown as sec^2 in the figure). The reason for the control to reach the target speed in a predetermined time is to prevent vibrations caused by the rotation of the rotary body 90 from being transmitted to the image forming apparatus 1 through the frame of the rotary body 90 and affecting image forming operations such as charging and exposure. With the developing roller 51y in contact with the photosensitive drum 2, the electrostatic latent image formed on the photosensitive drum 2 is developed with yellow toner (period BC in Figure 6).

[0053] In this embodiment, each of the developing rollers 51y, 51m, 51c, and 51k is an elastic roller having a metal shaft coated with rubber. At the developing position, each of the developing rollers 51y, 51m, 51c, and 51k develops an electrostatic latent image while in contact with the photosensitive drum 2. In other words, the image forming apparatus 1 in this embodiment employs a contact development method.

[0054] When the yellow toner image is developed, the yellow toner image on the photosensitive drum 2 is primarily transferred onto the intermediate transfer belt 10a by the primary transfer roller 11 arranged inside the intermediate transfer belt 10a shown in FIG.

[0055] After the electrostatic latent image formed on the photosensitive drum 2 is developed with yellow toner, the cam 96 rotates again to swing the rotary body 90 clockwise around the swing shaft 91, thereby separating the developing roller 51y from the photosensitive drum 2. In this state, the rotary 90 is rotated clockwise around the rotation axis 90C, causing the developing unit 50m to start moving to the magenta developing position (timing D in Figure 6). The ramp-up and ramp-down of the rotary rotation speed at this time is also controlled so that it reaches the target speed within a predetermined time Δt1.

[0056] In this embodiment, the rotary body 90 does not rotate during the contact / separation operation between the developing roller 51 and the photosensitive drum 2, but in order to shorten the image formation time, the contact / separation operation between the developing roller 51 and the photosensitive drum 2 may be performed while the rotary body 90 is rotating. In this case, however, in order to prevent vibrations caused by the contact / separation between the developing roller 51 and the photosensitive drum 2 from affecting image formation operations such as charging and exposure, it is necessary to take more time than before to increase and decrease the rotary rotation speed.

[0057] In this way, the rotary body 90 is rotated 90° at a time to sequentially move the developing rollers 51m, 51c, and 51k to the developing positions, thereby forming toner images of each color. That is, after a yellow toner image is formed on the intermediate transfer belt 10a, the rotary body 90 assumes the magenta developing position (timing E in FIG. 6), and a magenta toner image is formed on the intermediate transfer belt 10a. Similarly, after a magenta toner image is formed on the intermediate transfer belt 10a, the rotary body 90 assumes the cyan developing position, and a cyan toner image is formed on the intermediate transfer belt 10a. After a cyan toner image is formed on the intermediate transfer belt 10a, the rotary body 90 assumes the black developing position, and a black toner image is formed on the intermediate transfer belt 10a. When forming color images continuously, after a black toner image is formed on the intermediate transfer belt 10a, the rotary body 90 again assumes the yellow developing position, and each color is developed sequentially. When not forming color images continuously, the rotary body 90 returns to the standby position.

[0058] Then, primary transfer is repeated so that the four color toner images are superimposed on the intermediate transfer belt 10a, thereby forming a color image on the intermediate transfer belt 10a. Note that the secondary transfer roller 12 and cleaning device 13 are not in contact with the intermediate transfer belt 10a until the color image is formed on the intermediate transfer belt 10a. After the color image is formed on the intermediate transfer belt 10a, the secondary transfer roller 12 and cleaning device 13 come into contact with the intermediate transfer belt 10a to prepare for secondary transfer. Meanwhile, a sheet S is fed from a sheet storage unit 300 provided at the bottom of the image forming apparatus 1 by a pickup roller 310. The sheet S is separated into individual sheets by a feed roller 311 and a separation roller 312 and then fed to a pair of conveying rollers 320. The pair of conveying rollers 320 sends the fed sheet S to a transfer unit (secondary transfer unit), which is a nip between the intermediate transfer belt 10a and the secondary transfer roller 12. The color image on the intermediate transfer belt 10a is transferred (secondary transfer) to the surface of the conveyed sheet S.

[0059] The sheet S onto which the color image has been transferred is sent to the fixing device 40. In the fixing device 40, the sheet S is heated and pressurized, and the image is fixed onto the sheet S. After passing through the fixing device 40, the sheet S is discharged outside the image forming apparatus 1 as a finished product.

[0060] On the other hand, when a black monochrome image is formed on the sheet S, the rotary body 90 is rotated to move from the standby position to the black developing position. In this state, an electrostatic latent image is formed on the surface of the photosensitive drum 2 by charging and exposing the photosensitive drum 2, and then the electrostatic latent image is developed with black toner by the developing roller 51k located at the developing position. When black monochrome images are to be formed consecutively, development continues in the black developing position. When black monochrome images are not to be formed consecutively, the rotary body 90 returns to the standby position. The black toner image is primarily transferred to the intermediate transfer belt 10a, and then secondarily transferred to the sheet S. The subsequent processes are the same as those for color images.

[0061] (Toner supply operation) The operation of replenishing toner from the toner cartridge 70 to the developing unit 50 according to this embodiment will be described with reference to Figure 7. Figure 7 is a diagram illustrating the position in which toner is replenishing from the toner cartridge 70 to the developing unit 50. The position of the rotary body 90 in which toner is replenishing from the toner cartridge 70 to the developing unit 50 when the rotary body 90 is rotated once will be referred to as the replenishing position.

[0062] The toner contained in the toner storage portion 71a of the toner cartridge 70 is discharged through the discharge opening 71b and received in the developer-side storage portion 53a through the receiving opening 53b. Because toner is replenished by gravity, the replenishment posture is one in which the communication portion 60 formed by the discharge opening 71b of the toner cartridge 70 to be replenished and the receiving opening 53b of the development unit 50 faces downward in the vertical direction relative to the horizontal. The direction of the communication portion 60 is the direction in which the communication portion 60 is viewed from the toner storage portion 71a, and is indicated by arrow 701 in FIG. 7 . For example, the replenishment posture for yellow in this embodiment begins with a posture slightly rotated clockwise from the horizontal posture shown in FIG. 7(a). The replenishment posture then extends through the positions shown in FIGS. 7(b), 7(c), and 7(d) in which the communication portion 60 faces downward in the vertical direction relative to the horizontal, and continues until the position shown in FIG. 7(e) immediately before the communication portion 60 becomes horizontal again. On the other hand, when the communication portion 60 formed by the discharge opening 71b of the toner cartridge 70 and the receiving opening 53b of the developing unit 50 is oriented horizontally or vertically upward from the horizontal, the communication portion 60 is closed by the sealing member 55. Therefore, toner does not flow back from the developing unit 50 to the toner cartridge 70.

[0063] In this replenishment posture, the toner contained in the toner container 71a is discharged from the discharge opening 71b, and the toner discharged from the discharge opening 71b is received in the developer-side container 53a through the receiving opening 53b. The toner contained in the developer-side container 53a is supplied to the developing roller 51. The toner contained in the toner container 71a is supplied to the developing roller 51 via this route.

[0064] (Toner supply failure and resolving sequence) However, if the toner cartridge 70 is left unused for a long period of time, the toner contained in the toner storage portion 71a may adhere to the wall surfaces or to each other, making it difficult for the toner to be supplied to the developer-side storage portion 53a. Adhesion within the toner storage portion 71a is particularly likely to occur in high-temperature, high-humidity environments. The adhering toner remains in the toner storage portion 71a without being supplied to the developer-side storage portion 53a. The remaining toner is wasted because it is replaced with a new toner cartridge without being used.

[0065] Therefore, in this embodiment, a rotary operation mode is implemented with the aim of loosening the toner adhering to the toner storage section 71a. This operation mode will be explained using Figures 8 and 9. Figure 8 is a diagram showing, in chronological order, the flow of drive control of the rotary body 90 when loosening the toner adhering to the yellow toner cartridge 70y. Figure 8(a) is a diagram showing the rotary rotation speed when the rotary body 90 is driven and controlled, and Figure 8(b) is a diagram showing the rotary rotation acceleration when the rotary body 90 is driven and controlled. Figure 9 is a diagram showing the attitude of the yellow toner cartridge 70y during each drive control.

[0066] The rotary body 90 is rotated 90 degrees clockwise from the standby position (Timing A in FIG. 8) shown in FIG. 9(a). This causes the rotary body 90 to assume the acceleration / deceleration operation start position (Timing B in FIG. 8) shown in FIG. 9(b). In the acceleration / deceleration operation start position, the direction (indicated by arrow 901) of the communication portion 60 formed by the discharge opening 71b of the yellow toner cartridge 70y and the receiving opening 53b of the developing unit 50y is oriented vertically downward rather than horizontally.

[0067] Next, the rotary body 90 is driven (i.e., accelerated) for a time Δt2 that is shorter than the ramp-up time Δt1 of the rotational speed of the rotary body 90 during image formation shown in Figure 6, and then immediately stopped (i.e., decelerated) for an acceleration / deceleration operation (period C in Figure 8). In this embodiment, Δt2 is 50 msec, and the maximum acceleration at that time is 4800° / sec. 2When this operation mode is in effect, image formation is not in progress, so the rotary body 90 can be suddenly driven and stopped. This acceleration / deceleration operation starts the rotary rotation in a time Δt2 that is shorter than the start-up time Δt1 of the rotational speed of the rotary body 90 during image formation, and when decelerating, stops the rotary rotation in the same time Δt2. Therefore, when focusing particularly on the maximum absolute value of acceleration, the acceleration during rotation during this acceleration / deceleration operation shown in Figure 8(b) is greater than the acceleration during rotation during image formation shown in Figure 6(b).

[0068] This acceleration / deceleration action applies an inertial force to the toner adhering to the toner storage section 71a, breaking up the toner clumps. The toner adhering to walls A and B of the toner storage section 71a in FIG. 9(b) falls directly into the developer-side storage section 53a due to the inertial force, or falls into the developer-side storage section 53a due to the inclination of wall C, and is replenished. This acceleration / deceleration action rotates the rotary body 90 approximately 20° clockwise in FIG. 9. Performing this action twice rotates the rotary body 90 a total of approximately 40°, reaching the position shown in FIG. 9(c). Note that the acceleration / deceleration action is not limited to two actions, and may be performed at least twice or more. This action breaks up the toner adhering to walls A and B of the toner storage section 71a in FIG. 9(b), as well as toner adhering to wall D of the toner storage section 71a in FIG. 9(d). After this action is completed, the rotary body 90 rotates clockwise and returns to the standby position (Timing D in FIG. 8).

[0069] In this embodiment, two acceleration / deceleration operations are performed in Figure 8, but the number of times is not limited to this; even one operation is effective, and the effect increases with more operations. Therefore, Figure 9(d) shows the posture at the completion of the acceleration / deceleration operation shown in period C of Figure 8 from the state of Figure 9(c). The rotary 90 in Figure 9(d) has rotated 40° clockwise from Figure 9(c), during which a third acceleration / deceleration operation can be performed. As described above, a fourth acceleration / deceleration operation can also be performed. By repeating acceleration / deceleration two or more times, i.e., multiple times, a greater toner loosening effect can be achieved.

[0070] The rotary acceleration / deceleration operation mode is executed immediately before the user replaces the toner cartridge 70, when the toner in the toner cartridge toner storage compartment 71a is low, or when the toner in the developer-side storage compartment 53a is low. The immediately before the user replaces the toner cartridge 70 may be, for example, when the user performs an operation to replace the toner cartridge 70, i.e., when the user performs an operation to move the toner cartridge of the desired color to the retracted position. The operation unit 31 can inform the user that the user is about to replace the toner cartridge 70 by performing this operation. As mentioned above, the remaining toner amount in the toner cartridge 70 is calculated using the amount of toner consumed based on the count of the number of image dots detected by the pixel count unit 309 and stored in RAM 307. After each image formation, the remaining toner amount in the toner cartridge 70 stored in RAM 307 is read, and this operation mode is executed after image formation before the remaining toner amount reaches zero. Even if the remaining toner amount in the toner cartridge 70 stored in RAM 307 is still sufficient, this operation mode is executed when the developer unit remaining amount detection sensor 308 detects that the remaining toner amount in the developer unit 50 has crossed a certain threshold. Crossing the threshold can be rephrased as falling below the threshold. Even if there is sufficient toner remaining in the toner cartridge 70, the toner may adhere to the wall of the toner accommodating portion 71a, preventing the toner from being supplied to the developer-side accommodating portion 53a of the developer unit 50, resulting in a decrease in the toner amount in the developer-side accommodating portion 53a. A decrease in the toner amount in the developer-side accommodating portion 53a could damage components such as the developing roller 51. To prevent this, this operation mode is executed when the developer unit remaining amount detection sensor 308 detects that the remaining toner amount in the developer unit 50 has crossed a certain threshold, loosening the toner in the toner cartridge 70 so that it can be replenished to the developer-side accommodating portion 53a.

[0071] This operation mode may also be executed when there is a large amount of toner remaining in the toner cartridge 70 or the developing unit 50. For example, this mode may be executed when the image forming apparatus has not been used for a long period of time, or when the user requests it. Although executing this operation mode increases the rotary rotation speed, when there is unattached toner in the toner cartridge 70, accelerating and decelerating the rotary causes the unattached toner to collide with the adhered toner, thereby increasing the toner loosening effect.

[0072] Although the rotary acceleration / deceleration operation mode for the yellow cartridge 70y has been described as an example in this embodiment, the same effect can be obtained with the magenta cartridge 70m, cyan cartridge 70c, and black cartridge 70k by performing rotary acceleration / deceleration operation in the toner supply posture shown in this embodiment.

[0073] As described above, by implementing the rotary operation mode in this embodiment, it is possible to loosen toner clumps adhering to the toner storage portion 71a of the toner cartridge 70, thereby preventing poor toner supply from the toner cartridge 70 to the developing unit 50. This makes it possible to use the toner in the toner cartridge more efficiently than ever before.

[0074] FIG. 17 shows an example of a control procedure for the control unit 31 to perform a toner loosening operation or a rotary acceleration / deceleration operation. FIG. 17(A) shows a process for performing an acceleration / deceleration operation when the remaining toner amount falls below a threshold, and FIG. 17(B) shows an example for performing an acceleration / deceleration operation when the image forming apparatus 1 has not been used for a time exceeding the threshold. Both of the procedures in FIG. 17 are implemented by the CPU 311 of the control unit 31 executing a program read from memory 312. The remaining toner amount detection process and non-use time measurement process shown in FIG. 17 may be performed periodically, for example. However, the non-use time measurement process may be performed less frequently than the remaining toner amount detection process. The procedure in FIG. 17 is more effective when toner cartridges 70 are installed. Therefore, it may be determined whether all toner cartridges 70 are installed prior to the process in FIG. 17. If not, the process may not be performed, or a message prompting the user to install a toner cartridge 70 may be output.

[0075] 17A, when the remaining toner amount detection process is executed, first, control unit 31 compares the remaining amount of toner in toner cartridge 70 with a threshold value (S1701). Although it has been explained that the remaining amount of toner and threshold value in toner cartridge 70 and developing unit 50 are managed by video controller 30, control unit 31 may obtain these values ​​from video controller 30 and perform the control in FIG. 17. Alternatively, control unit 31 may manage the remaining amount of toner in place of video controller 30 and store the threshold value.

[0076] If the control unit 31 determines that the amount of toner remaining in the toner cartridge 70 is less than the threshold, the process branches to S1705 (S1702-YES) and determines whether image formation is in progress (S1705). If the control unit 31 determines that image formation is not in progress, the control unit 31 executes the rotary acceleration / deceleration operation described with reference to FIG. 8 (S1706). In this case, the control unit 31 controls the motor M1, which is the drive source, to perform this operation. In S1706, the rotary acceleration / deceleration operation is executed for the development unit or toner cartridge for which the amount of toner remaining is determined to be less than the threshold. In this case, the phase of the rotary 90 is adjusted so that the target development unit 50 is positioned at the position of the yellow development unit 50y in the standby position shown in FIG. 9(a), and the rotary acceleration / deceleration operation is executed from that state.

[0077] On the other hand, if the control unit 31 determines that the amount of toner remaining in the toner cartridge 70 is equal to or greater than the threshold, it compares the amount of toner remaining in the development unit 50 with the threshold (S1704). If the control unit 31 determines that the amount of toner remaining in the development unit 50 is less than the threshold, it branches to S1705. If it determines that an image formation operation is not in progress, it executes the rotary acceleration / deceleration operation as described in FIG. 8 (S1706). If the control unit 31 determines that the amount of toner remaining in the toner cartridge 70 is equal to or greater than the threshold and that the amount of toner remaining in the development unit 50 is also equal to or greater than the threshold, it ends the process. Note that the thresholds in S1701 and S1712 may be different values ​​and may be referred to as a first threshold and a second threshold, respectively.

[0078] When the non-use time measurement process of FIG. 17B is executed, the control unit 31 first compares the non-use time of the image forming apparatus 1 with a threshold value (S1711). The non-use time may be determined by, for example, storing the time each time the image forming apparatus 1 is used and calculating the elapsed time from the most recent stored time to the current time. Of course, this is just one example, and other methods may be used. If the control unit 31 determines that the non-use time is longer than the threshold value, the process branches to S1713 (S1712-YES). If the control unit 31 determines that an image forming operation is not currently in progress (S1713-NO), the control unit 31 executes the rotary acceleration / deceleration operation described with reference to FIG. 8 (S1714). On the other hand, if the control unit 31 determines that the non-use time is equal to or less than the threshold value, the process ends. Unlike S1706, in S1714, the control unit 31 executes the rotary acceleration / deceleration operation for all development units. This is because the need to loosen toner is not limited to toner of a specific color. As explained above, even if the rotary 90 is accelerated and decelerated twice, the rotation angle, i.e., the phase, of the rotary advances by only 40 degrees. Therefore, the rotary acceleration and deceleration can be completed for all color development units while the rotary 90 makes one full rotation.

[0079] The above procedure allows the rotary to be accelerated or decelerated based on the remaining toner amount or the time of non-use. In addition, as described above, step S1705 may be executed to accelerate or decelerate the rotary when the user performs an operation to replace a toner cartridge or when the user issues an instruction to accelerate or decelerate the rotary.

[0080] In this embodiment, the yellow development unit 50y and toner cartridge 70y are used as examples. However, the same applies to the development units 50 and toner cartridges 70b of other colors. The positions of the development units 50 and toner cartridges 70b other than yellow in the standby position are different from those shown in FIG. 9A. However, the effect of loosening the toner can be obtained by accelerating and decelerating the rotary 90. However, the direction of the communication portion does not necessarily face downward along the vertical direction. Therefore, to further enhance the effect of supplying toner from the toner cartridge 70 to the development unit 50, the development units and toner cartridges of each color are moved to the positions of the yellow development unit 50y and toner cartridge 70y in the standby position shown in FIG. 9A. The rotary can then be accelerated and decelerated based on this position.

[0081] Also, the determination in step S1705 may be made immediately before step S1701 and immediately before step S1711, and the process may be terminated if image formation is in progress.

[0082] [Embodiment 2] In embodiment 1, rotary acceleration / deceleration operations were performed only in a position where the direction of the communication portion 60 formed by the discharge opening 71b of the toner cartridge from which the adhering toner was to be loosened and the receiving opening 53b of the developing unit 50y was vertically downward rather than horizontal.

[0083] In this embodiment, by performing rotary acceleration / deceleration operations even in postures other than those described above, more toner adhering to all wall surfaces of the toner storage section 71a is loosened, the toner is collected, and then efficiently replenished to the development-side storage section 53a of the development unit 50. The overall configuration of the image forming apparatus and image forming operations other than the rotation control in the rotary operation mode are the same as in embodiment 1, and therefore a description thereof will be omitted. Furthermore, the implementation timing of the rotary operation mode in this embodiment is also the same as in embodiment 1, and therefore a description thereof will be omitted.

[0084] The rotary operation mode for replenishing toner from the toner cartridge 70 to the developing unit 50 according to this embodiment will be described with reference to Figures 10 and 11. Figure 10 is a time-series diagram showing the flow of drive control of the rotary body 90 when loosening toner adhering to the yellow toner cartridge 70y. Figure 10(a) is a diagram showing the rotary rotation speed when the rotary body 90 is driven and controlled, and Figure 10(b) is a diagram showing the rotary rotation acceleration when the rotary body 90 is driven and controlled. Figure 11 is a diagram showing the attitude of the yellow toner cartridge 70y during each drive control. The rotary operation mode of this embodiment performs a preliminary operation for loosening and collecting adhering toner, and a main operation for replenishing toner to the developing-side accommodating section 53a.

[0085] (Preparatory action) The rotary body 90 is rotated 230° clockwise from the standby position shown in FIG. 11(a) (timing A in FIG. 10) and moved to the preliminary operation position 1 shown in FIG. 11(b) (timing B in FIG. 10). The preliminary operation position 1 is a position in which the toner adhering to walls C and D of the toner storage section 71a separates from the walls due to gravity and falls. Next, the rotary body 90 is driven for a time Δt2 that is shorter than the ramp-up time Δt1 of the rotational speed of the rotary body 90 during image formation shown in FIG. 6, and an acceleration / deceleration operation is performed to immediately bring it to a sudden stop (period C in FIG. 10). In this embodiment, the time Δt2 is 50 msec, and the maximum acceleration value at that time is 4800° / sec 2 Since image formation is not in progress during this operation mode, the rotary body 90 can be suddenly driven and stopped. This acceleration / deceleration operation ramps up the rotary rotation in a time Δt2 that is shorter than the ramp-up time Δt1 of the rotary body 90's rotational speed during image formation. Therefore, the acceleration during this acceleration / deceleration operation shown in FIG. 10(b) is greater than the acceleration during image formation shown in FIG. 6(b). During this operation, the rotary rotates approximately 20° clockwise, and by performing this operation twice, it rotates a total of approximately 40°. This acceleration / deceleration operation applies an inertial force to the toner adhering to the toner storage section 71a, breaking up the toner clumps. Gravity causes the toner adhering to walls C and D of the toner storage section 71a in FIG. 11(b) to accumulate at the bottom of the toner storage section 71a in the preliminary operation posture 1.

[0086] Next, the rotary 90 is rotated clockwise by approximately 50° to move to the preparatory operation posture 2 shown in FIG. 11(c) (Timing D in FIG. 10). In preparatory operation posture 2, the toner adhering to walls B and C of the toner storage section 71a separates from the walls due to gravity and falls. In preparatory operation posture 2, acceleration and deceleration are performed again (Period E in FIG. 10). This acceleration and deceleration applies an inertial force to the toner adhering to the toner storage section 71a, breaking up the toner clumps, and the toner adhering to walls B and C of the toner storage section 71a in FIG. 11(c) accumulates at the bottom of the toner storage section 71a in preparatory operation posture 2 due to gravity.

[0087] Furthermore, the rotary 90 is rotated clockwise by approximately 50° to move to the preparatory operation posture 3 shown in FIG. 11(d) (timing F in FIG. 10). In the preparatory operation posture 3, toner adhering to walls A and B of the toner storage section 71a is released from the walls by gravity and falls. In the preparatory operation posture 3, acceleration and deceleration are performed again (period G in FIG. 10). This acceleration and deceleration applies an inertial force to the toner adhering to the toner storage section 71a, breaking up the toner clumps. The toner adhering to walls A and B of the toner storage section 71a in FIG. 10(d) accumulates at the bottom of the toner storage section 71a in the preparatory operation posture 3 by gravity. The acceleration and deceleration operations performed thus far as preparatory operations loosen the toner adhering to all the walls of the toner storage section 71a by inertial force, including the toner adhering to wall C, which was not sufficiently loosened in the first embodiment, and the toner is collected at the bottom of the toner storage section 71a in the preparatory operation posture 3.

[0088] (This operation) Once all the toner has been collected at the bottom of the toner storage compartment 71a through the acceleration and deceleration operations in the preliminary operation, the rotary 90 is rotated clockwise by approximately 50° and moved to the main operation position shown in FIG. 11(e) (Timing H in FIG. 10). In this main operation position, the communication portion 60 formed by the discharge opening 71b of the toner cartridge 70y and the receiving opening 53b of the developing unit 50y is oriented vertically downward rather than horizontally. Here, acceleration and deceleration operations are performed again, allowing the collected toner to be effectively replenished to the developing-side storage compartment 53a (Period I in FIG. 10). After the main operation is completed, the rotary 90 is rotated clockwise and returns to the standby position again (Timing J in FIG. 10).

[0089] As described above, in this embodiment, not only is the main operation performed in the first phase, but also the preparatory operation is performed in the second phase, which is 90 degrees earlier than the first phase. In this embodiment, the first preparatory operation is performed in a phase 270 degrees earlier than the first phase, and then a total of three preparatory operations are performed in phases each advanced by 90 degrees. Therefore, in this embodiment, the second phase includes multiple phases that are shifted by 90 degrees or earlier than the first phase. However, the present invention is not limited to this. If at least one preparatory operation is performed prior to the main operation, the effect of supplying toner to the developing unit 50 can be improved.

[0090] The rotary's acceleration and deceleration operations are performed within a certain range of rotation angle of the rotary (in the above example, one acceleration and 20 degrees in principle), so the first phase can be said to be the phase at which the operation begins, and it can also be said that acceleration and deceleration are performed within a specified phase range.

[0091] Furthermore, when three preparatory operations and a main operation are performed for yellow as in this embodiment, three preparatory operations and one main operation are also performed for the development units 50 of other colors, although in a different order. Therefore, by performing two sets of loosening operations, each set consisting of three preparatory operations and one main operation while rotating the rotary 90 by 90 degrees, it is possible to perform three preparatory operations followed by one main operation for the development units 50 of all colors.

[0092] In this embodiment, two acceleration / deceleration operations are performed as one set, but the number of times is not limited to this; even one operation is effective, and the effect increases as the number of operations increases.

[0093] Furthermore, although the present embodiment has been described taking the rotary acceleration / deceleration operation mode for the yellow cartridge 70y as an example, the same effect can be obtained for the magenta cartridge 70m, cyan cartridge 70c, and black cartridge 70k.

[0094] [Embodiment 3] In the first and second embodiments, the rotary acceleration / deceleration operation was performed by rotating the rotary body 90 in the rotation direction R2 during image formation. If the rotary body 90 were rotated only in the forward direction, a simplified motor driver circuit could reduce motor costs. However, with only forward rotation, the rotary phase advances with each acceleration / deceleration operation, making it impossible to repeatedly perform acceleration / deceleration at the desired phase in a short period of time. Therefore, in this embodiment, acceleration / deceleration operations are performed in both the rotary rotation direction R2 and its reverse rotation direction to enhance the toner loosening effect. By alternately performing the rotary acceleration / deceleration operations in both directions, the rotary phase does not advance, and more toner can be loosened in the toner storage section 71a without limiting the number of times, thereby efficiently supplying the toner to the developer-side storage section 53a. Furthermore, because the reverse rotation of the rotary body 90 is not performed during normal image formation, the rotary operation mode of this embodiment applies a force to the rotary body 90 that is not applied during normal image formation, effectively loosening the toner. The overall configuration of the image forming apparatus and the image forming operation other than the rotation control in the rotary operation mode are the same as in embodiment 1, and therefore a description thereof will be omitted. Also, the rotary operation mode of this embodiment is a rotation control that performs the same preparatory operation and main operation as in embodiment 2, except for the acceleration / deceleration operation, and therefore a description thereof will be omitted. Also, the execution timing of the rotary operation mode of this embodiment is the same as in embodiment 1, and therefore a description thereof will be omitted.

[0095] The acceleration and deceleration operation of the rotary operation mode in which toner is replenished from the toner cartridge 70 to the developing unit 50 according to this embodiment will be described with reference to Figure 12. Figure 13 is a time-series diagram showing the flow of drive control of the rotary main body 90 when loosening toner adhering to the yellow toner cartridge 70y according to this embodiment. Figure 12(a) is a diagram showing the rotary rotation speed when drive control is performed on the rotary main body 90, and Figure 12(b) is a diagram showing the rotary rotation acceleration when drive control is performed on the rotary main body 90.

[0096] As described above, in this embodiment, rotary acceleration / deceleration operations are performed in both the rotary rotation direction R2 (forward rotation direction) shown in Figure 1 and its reverse rotation direction. After moving from the standby position shown in Figure 11(a) (Timing A in Figure 12) to the preliminary movement position 1 in Figure 11(b) (Timing B in Figure 12), the rotary body 90 is driven in the R2 direction for a start-up time Δt2, and then an acceleration / deceleration operation is performed to immediately bring it to a sudden stop (Period C in Figure 12). In this embodiment, the time Δt2 is 50 msec, and the maximum acceleration value at that time is 4800° / sec 2 Next, the rotary body 90 is driven in the opposite direction to the R2 direction (reverse rotation direction) for the same start-up time Δt2, and then an acceleration / deceleration operation is performed to immediately bring it to a sudden stop (period D in Figure 12). This forward and reverse rotation operation returns the rotary phase to its original position, preparatory operation position 1. This acceleration / deceleration operation applies an inertial force to the toner adhering to the toner storage section 71a, breaking up the toner clumps, and the toner adhering to walls C and D of the toner storage section 71a in Figure 11(b) accumulates at the bottom of the toner storage section 71a in preparatory operation position 1 due to gravity.

[0097] 11(c) and 11(d), similarly, acceleration and deceleration are performed at high speed in the R2 direction (forward rotation direction) and in the direction opposite to the R2 direction (reverse rotation direction). By doing so, all toner adhering to the walls of the toner storage section 71a is collected at the bottom of the toner storage section 71a in preparatory operation position 3. Preparatory operation position 2 is a position in which the rotary 90 is rotated approximately 90 degrees after the rotary is accelerated and decelerated in preparatory operation position 1. Similarly, preparatory operation position 3 is a position in which the rotary 90 is rotated approximately 90 degrees after the rotary is accelerated and decelerated in preparatory operation position 2.

[0098] 11(e), the toner is accelerated and decelerated in the R2 direction (forward rotation direction) at high speed, and in the reverse direction (reverse rotation direction) to the R2 direction at high speed. This allows the toner that has been removed or loosened from the wall to be effectively replenished to the developer-side accommodating portion 53a.

[0099] In this embodiment, from one preparatory operation position or main operation position, high-speed acceleration / deceleration operations are performed once in the R2 direction (forward rotation direction) and once in the direction opposite to the R2 direction (reverse rotation direction). However, the number of times is not limited to this, and the effect is greater the more times the number of times is. Furthermore, in this embodiment, acceleration / deceleration operations can be performed without changing the rotary phase, so acceleration / deceleration operations at the most effective rotary phase can be repeated in a short period of time. Furthermore, although this embodiment has been described using the rotary acceleration / deceleration operation mode for the yellow cartridge 70y as an example, similar effects can be obtained with the magenta cartridge 70m, cyan cartridge 70c, and black cartridge 70k.

[0100] [Embodiment 4] In the first to third embodiments, the rotation of the rotary body 90 is controlled to accelerate the toner, thereby applying force to loosen the toner adhering to the toner storage portion 71a of the toner cartridge 70. In contrast, in the present embodiment, force is applied from the outside of the rotary body 90 to further loosen the toner, enhancing the effect.

[0101] Specifically, the cam 96 shown in FIG. 2 is rotated at a higher speed than during normal image formation, causing it to repeatedly collide with the frame of the rotary main body 90, thereby vibrating the entire rotary 90 and loosening the adhering toner. In other words, the cam 96 functions as a vibration unit. The overall configuration of the image forming apparatus and the image forming operation other than the cam 96 and rotary rotation control are the same as in the first embodiment, and therefore a description thereof will be omitted. Furthermore, the timing of implementing the rotary operation mode in this embodiment is also the same as in the first embodiment, and therefore a description thereof will be omitted.

[0102] FIG. 13 is a timeline illustrating the flow of drive control of the rotary body 90 when loosening toner adhering to the yellow toner cartridge 70y. FIG. 13(a) illustrates the rotary rotation speed when the rotary body 90 is driven and controlled, and FIG. 13(b) illustrates the inertial force acting on the toner adhering to the toner storage unit 70. The basic operation of the rotary is the same as in the second embodiment. However, in this embodiment, instead of accelerating and decelerating the rotary body 90, vibration is applied by rotating the cam 96 and causing it to collide with the frame of the rotary body 90. The drive source for driving the cam 96 may be, for example, one of the motors M3 shown in FIG. 15. Therefore, the rotation of the cam 96 is controlled by the control unit 31. First, after moving from the standby position shown in FIG. 11(a) (Timing A in FIG. 13) to the preparatory operation position 1 shown in FIG. 11(b) (Timing B in FIG. 13), the cam 96 rotates once at high speed, causing vibration to the frame of the rotary body 90 (Period C in FIG. 13). In the vibration preparatory operation posture 1, the developing roller 51y and the photosensitive drum 2 are not opposed to each other, so that even when the cam 96 is rotated, the photosensitive drum 2 and the developing roller 51y do not come into contact with each other, and vibration can be applied to the rotary body 90. Furthermore, when the cam 96 moves toward and away from the frame of the rotary body 90 at high speed, the rotary body 90 vibrates around the swing shaft 91. Therefore, an inertial force of a vector different from the inertial force obtained at the rotation axis 90C of the rotary body 90 can be applied to the adhering toner in the toner accommodating section 70.

[0103] The rotation of the cam 96 applies vibrations to the toner in the toner storage section 71a, which in turn applies an inertial force to the toner, thereby breaking up the toner clumps. Then, the toner that had been adhering to walls C and D of the toner storage section 71a in Figure 11(b) accumulates at the bottom of the toner storage section 71a in the preparatory operation posture 1 due to gravity.

[0104] 11(c) and 11(d), the cam 96 is rotated twice at high speed to vibrate the frame of the rotary body 90 (periods E and G in FIG. 13), thereby loosening the toner in the toner storage section 71a. The loosened toner eventually accumulates at the bottom of the toner storage section 71a in the preparatory operation posture 3.

[0105] Finally, in this operating position, the cam 96 is rotated once at high speed to vibrate the frame of the rotary body 90 (Fig. 13 - Period I), thereby effectively supplying the collected toner to the development-side storage section 53a.

[0106] In this embodiment, the cam 96 is rotated once in each of the preliminary operation posture and the main operation posture, but the number of rotations is not limited to this, and the greater the number of rotations, the greater the effect. Also, in this embodiment, since only the cam 96 outside the rotary body 90 is rotated, vibration can be applied in a shorter time than by rotating the rotary body 90, allowing for more effective toner loosening.

[0107] Furthermore, although the present embodiment has been described taking the rotary acceleration / deceleration operation mode for the yellow cartridge 70y as an example, the same effect can be obtained for the magenta cartridge 70m, cyan cartridge 70c, and black cartridge 70k.

[0108] (Variation) In this modified example, the toner particles are loosened more effectively by applying a force from outside the rotary body 90. While the vibration is applied by a cam 96 external to the rotary body 90 in the above example, a vibration actuator can also be used as an external vibration application device. A vibration actuator, installed outside the rotary body 90 and capable of contacting and separating from the rotary body 90, can be brought into contact with the frame at any rotary phase to apply vibration to the entire rotary body 90 and loosen the toner particles. Furthermore, since the rotary body 90 and cam 96 do not rotate, the operation can be performed quietly with minimal operating noise. As shown in FIG. 14, the vibration applied to the rotary body 90 is synchronized with the change in the rotary body 90's phase. Therefore, in this modified example, the vibration actuator (not shown) is also controlled by the control unit 31.

[0109] FIG. 14 is a diagram showing the flow of the rotary body 90 in time sequence when loosening the toner adhering to the yellow toner cartridge 70y.

[0110] First, after moving from the standby posture shown in FIG. 11(a) (Timing A in FIG. 14) to the preparatory operation posture 1 shown in FIG. 11(b) (Timing B in FIG. 14), the vibration actuator is activated to vibrate the frame of the rotary body 90 (Period C in FIG. 14). In this modified example, a rotary actuator (eccentric rotating mass type) that utilizes rotation is used as the vibration actuator to vibrate the rotary body 90. The vibration applied to the rotary body 90 by this vibration actuator applies inertial force to the toner adhering to the toner storage section 71a, thereby loosening the toner clumps. Then, the toner adhering to walls C and D of the toner storage section 71a in FIG. 11(b) accumulates at the bottom of the toner storage section 71a in the preparatory operation posture 1 due to gravity. In preparatory operation postures 2 and 3 shown in FIGS. 11(c) and 11(d), the vibration actuator is similarly activated to vibrate the frame of the rotary body 90 (Periods E and G in FIG. 14), loosening the toner in the toner storage section 71a. The loosened toner eventually accumulates at the bottom of the toner storage section 71 a in the preparatory operation posture 3 .

[0111] Finally, in this operating position, the vibration actuator is operated to vibrate the frame of the rotary body 90 (Fig. 14 - period I), thereby effectively supplying the collected toner to the development-side accommodating section 53a. After this operation is completed, the vibration actuator is again separated from the rotary frame 90f, and the rotary 90 is rotated to the standby position (Fig. 14 - timing J).

[0112] In this modified example, a rotary actuator (eccentric rotating mass type) that utilizes rotation is used as the vibration actuator, but a piezo actuator that utilizes the piezoelectric effect or an electromagnetic actuator that uses a coil can also be used. Furthermore, in this modified example, a vibration actuator is used to apply vibration to the entire rotary, but a configuration in which an impact is applied by colliding a member with the rotary frame 90f may also be used. Furthermore, this modified example has been described using the rotary acceleration / deceleration operation mode for the yellow cartridge 70y as an example, but similar effects can also be obtained with the magenta cartridge 70m, cyan cartridge 70c, and black cartridge 70k.

[0113] [Other Examples] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0114] Summary of embodiments The above embodiments can be summarized as follows: (Item 1) An image forming apparatus in which a first cartridge containing a first developer and a second cartridge containing a second developer are detachably mounted, a first developing unit including a first container that contains the first developer supplied from the first cartridge, and a first developing member that develops an electrostatic latent image formed on a photosensitive member using the first developer contained in the first container; a second developing unit including a second container that contains the second developer supplied from the second cartridge, and a second developing member that develops the electrostatic latent image formed on the photosensitive member using the second developer contained in the second container; a rotatable rotary including the first developing unit and the second developing unit; a drive unit that drives the rotary so that the rotary rotates; a control unit that controls the drive unit; and the first developer in the first cartridge is supplied to the first container by being discharged from a first discharge opening formed in the first cartridge to a first receiving opening formed in the first container, the rotary has a first supplying position in which a direction from the first discharge opening to the first receiving opening has a vertical downward component, and a first developing position in which the first developing member is capable of developing on the photosensitive member, the control unit controls the drive unit so that the rotary performs an acceleration / deceleration operation of accelerating and then decelerating at least twice or more during a period in which the rotary rotates from the first supply position to the first developing position. An image forming apparatus characterized by the above. (Item 2) Item 1, the image forming apparatus according to item 1, The rotation of the rotary is accelerated and decelerated alternately and repeatedly between a first rotation direction and a second rotation direction different from the first rotation direction. An image forming apparatus characterized by: (Item 3) Item 1 or 2, the image forming apparatus, The acceleration and deceleration of the rotation of the rotary is initiated in the first supply position. An image forming apparatus characterized by: (Item 4) Item 3. The image forming apparatus according to item 3, The acceleration and deceleration of the rotation of the rotary are initiated in a second replenishment position different from the first replenishment position before being initiated in the first replenishment position. An image forming apparatus characterized by: (Item 5) Item 4. The image forming apparatus according to item 4, The second supplying position includes a plurality of positions obtained by rotating the rotary by 90 degrees from the first supplying position. An image forming apparatus characterized by: (Item 6) 6. The image forming apparatus according to any one of items 1 to 5, The absolute value of the acceleration and deceleration of the rotation of the rotary is greater than the absolute value of the acceleration and deceleration of the rotary during image formation. An image forming apparatus characterized by: (Item 7) a developing unit for developing the image with a developer; a rotatably supported rotary that accommodates the developing unit and a cartridge that accommodates a developer to be supplied to the developing unit; a vibration applying unit that can come into contact with and move away from the rotary and applies vibration to the rotary; a control unit that controls the vibration of the vibration unit, The control unit controls the vibration unit to apply vibration to the rotary during a period when the development unit is not developing an image. An image forming apparatus characterized by: (Item 8) Item 7. The image forming apparatus according to item 7, The vibration unit is a cam that separates the rotary from a photosensitive drum on which an image developed by the developing unit is formed, and vibrates the rotary by rotation of the cam. An image forming apparatus characterized by: (Item 9) Item 7. The image forming apparatus according to item 7, The vibration unit is a vibration actuator that is in contact with the rotary. An image forming apparatus characterized by: (Item 10) 10. The image forming apparatus according to any one of items 1 to 9, The developing unit has an opening for receiving the developer supplied from the cartridge, and the opening has a sealing member for preventing the developer from moving from the developing unit to the cartridge. An image forming apparatus characterized by:

[0115] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0116] 1...image forming apparatus / 50...developing unit / 51...developing roller / 52...supply roller / 53...developing frame body / 53a...developing side storage section / 53b...receiving opening / 55...guide member / 70...toner cartridge / 71b...discharge opening / 90...rotary (rotary body)

Claims

1. An image forming apparatus in which a first cartridge containing a first developer and a second cartridge containing a second developer are detachably mounted, a first developing unit including a first container that contains the first developer supplied from the first cartridge, and a first developing member that develops an electrostatic latent image formed on a photosensitive member using the first developer contained in the first container; a second developing unit including a second container that contains the second developer supplied from the second cartridge, and a second developing member that develops the electrostatic latent image formed on the photosensitive member using the second developer contained in the second container; a rotatable rotary including the first developing unit and the second developing unit; a drive unit that drives the rotary so that the rotary rotates; a control unit that controls the drive unit; and the first developer in the first cartridge is supplied to the first container by being discharged from a first discharge opening formed in the first cartridge to a first receiving opening formed in the first container, the rotary has a first supplying position in which a direction from the first discharge opening to the first receiving opening has a vertically downward component, and a first developing position in which the first developing member is capable of developing on the photosensitive member, the control unit controls the drive unit so that the rotary performs an acceleration / deceleration operation of accelerating and then decelerating at least twice or more during a period in which the rotary rotates from the first supply position to the first developing position. An image forming apparatus characterized by:

2. 2. The image forming apparatus according to claim 1, The rotation of the rotary is accelerated and decelerated alternately and repeatedly between a first rotation direction and a second rotation direction different from the first rotation direction. An image forming apparatus characterized by:

3. 2. The image forming apparatus according to claim 1, The acceleration and deceleration of the rotation of the rotary is initiated in the first supply position. An image forming apparatus characterized by:

4. 4. The image forming apparatus according to claim 3, The acceleration and deceleration of the rotation of the rotary are initiated in a second replenishment position different from the first replenishment position before being initiated in the first replenishment position. An image forming apparatus characterized by:

5. 5. The image forming apparatus according to claim 4, The second supplying position includes a plurality of positions obtained by rotating the rotary by 90 degrees from the first supplying position. An image forming apparatus characterized by:

6. 2. The image forming apparatus according to claim 1, The absolute value of the acceleration and deceleration of the rotation of the rotary is greater than the absolute value of the acceleration and deceleration of the rotary during image formation. An image forming apparatus characterized by:

7. a developing unit for developing the image with a developer; a rotatably supported rotary that accommodates the developing unit and a cartridge that accommodates a developer to be supplied to the developing unit; a vibration applying unit that can come into contact with and move away from the rotary and applies vibration to the rotary; a control unit that controls the vibration of the vibration unit, The control unit controls the vibration unit to apply vibration to the rotary during a period when the development unit is not developing an image. An image forming apparatus characterized by:

8. 8. The image forming apparatus according to claim 7, The vibration unit is a cam that separates the rotary from a photosensitive drum on which an image developed by the developing unit is formed, and vibrates the rotary by rotation of the cam. An image forming apparatus characterized by:

9. 8. The image forming apparatus according to claim 7, The vibration unit is a vibration actuator that is in contact with the rotary. An image forming apparatus characterized by:

10. 8. The image forming apparatus according to claim 1, The developing unit has an opening for receiving the developer supplied from the cartridge, and the opening has a sealing member for preventing the developer from moving from the developing unit to the cartridge. An image forming apparatus characterized by:

Images