Image forming apparatus

Abstract

To compensate for the shortage of toner in a developer container during replacement of a toner cartridge.SOLUTION: An image forming apparatus has a rotary type developing device that holds a plurality of developing units in a rotary and rotates the rotary to move a target developing unit to a developing position. The developing units each comprise a toner container storing toner and a developer container having a developing section. The toner containers are removably held in the rotary in a replaceable manner. After replacement of the toner containers, the image forming apparatus performs a toner supply operation before performing development.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material using a developer. [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 developing rollers. Patent Document 1 describes an image forming apparatus equipped with a rotary equipped with multiple developing rollers and multiple toner cartridges (toner storage containers) that are each detachable from the rotary.

[0003] In such rotary development type image forming devices, toner from a toner cartridge is replenished to each developing unit connected through an opening. When the toner in a developing unit is low, it is only necessary to replace the toner cartridge with a new one, and the developing unit can continue to be used as is. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-183305 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the toner cartridge is replaced, there may not be enough toner in the developing unit. In such cases, because the toner cartridge is separate from the developing unit, a replenishment operation is required until a sufficient amount of toner is supplied to the developing unit after the toner cartridge is replaced. If a printing operation is performed without a sufficient amount of toner being replenished in the developing unit, the toner cannot be replenished from the toner cartridge to the developing unit in time, and there is a risk of image defects occurring due to insufficient toner supply.

[0006] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional examples, and has as its object to solve the problem of toner shortage in the developing device after replacing the toner cartridge. [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 to which a cartridge containing a developer can be detachably attached, comprising: a rotary including a developing unit capable of accommodating the cartridge attached thereto and configured to accommodate the developer supplied through an opening of the cartridge; a drive unit that rotates the rotary; a control unit that controls the drive unit, the control unit controls the drive unit to rotate the rotary to a first rotation phase at which the cartridge can be replaced when the cartridge is replaced, and to rotate the rotary to a second rotation phase at which the development is performed by the development unit when an image is developed using the developer supplied from the cartridge and contained in the development unit; When the control unit determines that a predetermined condition is satisfied, and when a first image forming operation is to be performed after the cartridge has been replaced, the control unit controls the drive unit to rotate the rotary from the first rotation phase to the second rotation phase via a third rotation phase in which the opening of the cartridge is projected downward along a vertical direction as viewed from inside the cartridge a plurality of times. An image forming apparatus characterized by the above features is provided. [Effects of the Invention]

[0008] According to the present invention, the problem of toner shortage in the developing device after replacing the toner cartridge can be resolved. [Brief explanation of the drawings]

[0009] [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] 1 is a cross-sectional view of an image forming apparatus according to a first embodiment. [Figure 3] FIG. 1 is a diagram showing a drive source of an image forming apparatus according to a first embodiment; [Figure 4] Schematic diagram of a developing unit and a toner cartridge according to the first embodiment. [Figure 5] Schematic diagram of a development unit and a toner cartridge at a supply position according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing the number of consecutive prints of an image with a print rate of 50% for N number of replenishment operations in the first embodiment. [Figure 7] FIG. 10 is a schematic diagram illustrating the movement of a development unit in Comparative Example 1 of Embodiment 1. [Figure 8] Schematic diagram showing the movement of the development unit in Example 1-1 of Embodiment 1. [Figure 9] Schematic diagram showing the movement of the development unit in the second embodiment. [Figure 10] 1 is a schematic diagram showing the posture of the toner cartridge 70 and the developing unit 50 during the replenishment process in the second embodiment, a diagram showing the amount of toner in the toner cartridge 70, and a comparison diagram with the first embodiment. [Figure 11] 1 is a perspective view showing the arrangement of trays 80y to 80k in the rotary 90. [Figure 12] A cross-sectional view showing the arrangement of trays 80y to 80k in the rotary 9. [Figure 13] FIG. 10 is a perspective view showing the drive configuration for inserting and removing the tray. [Figure 14] Cross-sectional view showing the drive structure for inserting and removing trays [Figure 15] 10 is a flowchart showing an example of a control procedure at the start of image formation processing; DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] [Embodiment 1] An image forming apparatus 1 according to a first embodiment will be described with reference to FIGS. 1 to 5. 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 intersecting the Z direction and the direction of a rotation axis 90C of a rotary body 90 (described later, the direction of the rotary's rotation axis) is referred to as the Y direction. The direction intersecting both the Z direction and the Y direction is referred to as the X direction. The X direction and the Y direction are preferably horizontal. Furthermore, the X direction, the Y direction, and the Z direction are preferably perpendicular to each other. Furthermore, as necessary, the directions of the arrows X, Y, and Z shown in each drawing will be represented as the +X side, the +Y side, and the +Z side, respectively, and the opposite sides will be represented as the -X side, the -Y side, and the -Z side, respectively.

[0012] (Overall configuration of image forming apparatus) First, we will explain the overall configuration of the image forming apparatus 1. The image forming apparatus 1 is a laser beam printer that forms an image on a sheet S by electrophotography. More specifically, the image forming apparatus 1 is a color laser beam printer equipped with four development units 50y, 50m, 50c, and 50k. As the sheet S, which is the recording material (recording medium), a variety of sheet materials of different sizes and materials can be used, including paper such as plain paper and cardboard, surface-treated sheet materials such as plastic film, cloth, and coated paper, and sheet materials of special shapes such as envelopes and index paper.

[0013] The general configuration and image forming operation of image forming apparatus 1 will be described with reference to Figures 1, 2, and 3. Figure 1 is a schematic diagram showing the cross-sectional configuration of image forming apparatus 1. Figure 2 is a diagram explaining the drive source of image forming apparatus 1. Figure 3 is a conceptual diagram showing the cross-section of toner cartridge 70 and the configuration for replenishing toner from toner cartridge 70 to developing unit 50.

[0014] The subscripts y, m, c, and k attached to the developing units 50y, 50m, 50c, and 50k, the toner cartridges 70y, 70m, 70c, and 70k, and the trays 80y, 80m, 80c, and 80k indicate the toner colors, which correspond to yellow, magenta, cyan, and black, respectively.

[0015] 1, the image forming apparatus 1 has an image forming apparatus main body (hereinafter referred to as apparatus main body) 1A and toner cartridges 70y, 70m, 70c, and 70k as toner containers that are detachably attached to the apparatus main body 1A. The apparatus main body 1A in this embodiment is the portion of the image forming apparatus 1 excluding the toner cartridges 70y, 70m, 70c, and 70k.

[0016] An apparatus main body 1A of the image forming apparatus 1 has a drum-shaped (cylindrical) electrophotographic photosensitive member (hereinafter referred to as photosensitive drum) 2 as an image carrier that carries an electrostatic latent image. Around the photosensitive drum 2, a charging roller 3, a scanner 4 as an exposure device, and a cleaning unit 6 are arranged.

[0017] The charging roller 3 is an example of a charging mechanism for uniformly charging the photosensitive drum 2. The scanner 4 is an example of an exposure mechanism for irradiating the photosensitive drum 2 with laser light according to image information to expose it. By irradiating the charged photosensitive drum 2 with laser light, an electrostatic latent image is formed on both sides of the photosensitive drum 2. The cleaning unit 6 is an example of a cleaning mechanism for removing toner remaining on the surface of the photosensitive drum 2.

[0018] The apparatus main body 1A also has a video controller 30 that receives image information from an external device (not shown) such as a host computer, and a control section 31 that transmits a print signal.

[0019] Furthermore, the apparatus main body 1A has a sheet storage section 300, a pickup roller 310, a feed roller 311, a separation roller 312, a pair of conveying rollers 320, a secondary transfer roller 12, a fixing device 40, and an intermediate transfer unit 10. The pickup roller 310 is an example of a feeding mechanism that feeds the sheet S. The feed roller 311 and the separation roller 312 are examples of a separation conveying unit that separates and conveys the sheets S one by one by frictional force. The secondary transfer roller 12 is an example of a transfer mechanism that transfers an image from the intermediate transfer belt 10a to the sheet S.

[0020] The intermediate transfer unit 10 has an intermediate transfer belt 10a, a belt drive roller 10b, a tension roller 10c, a cleaning device 13, and a primary transfer roller 11. The intermediate transfer belt 10a is an example of an intermediate transfer body that carries an image transferred (primary transfer) from the photosensitive drum 2 and transports it to be transferred (secondary transfer) to a sheet S. The intermediate transfer belt 10a is stretched over the belt drive roller 10b and the tension roller 10c. The belt drive roller 10b is a drive member that is rotationally driven by a drive source to transport the intermediate transfer belt 10a.

[0021] The apparatus main body 1A also has a rotary body (rotary, rotating body) 90 having developing units 50y, 50m, 50c, and 50k. As will be described later, in this embodiment, trays 80y, 80m, 80c, and 80k are attached to the rotary body 90. Toner cartridges 70y, 70m, 70c, and 70k are removably attached to the trays 80y, 80m, 80c, and 80k. In other words, the rotary body 90 is configured to accommodate multiple toner cartridges 70. Toner cartridge 70k is an example of a first toner cartridge. Toner cartridge 70m is an example of a second toner cartridge. Toner cartridge 70y is an example of a third toner cartridge. Toner cartridge 70c is an example of a fourth toner cartridge. This is just an example, and any color may be represented by any number as long as it is unique. The same applies to tray 80.

[0022] Tray 80k is an example of a first support member that supports a first toner cartridge. Tray 80m is an example of a second support member that supports a second toner cartridge. Tray 80y is an example of a third support member that supports a third toner cartridge. Tray 80c is an example of a fourth support member that supports a fourth toner cartridge.

[0023] The developing units 50y, 50m, 50c, and 50k are examples of developing means that develop (visualize) the electrostatic latent image formed on the photosensitive drum 2 into a toner image using toner of a corresponding color. The developing units 50y, 50m, 50c, and 50k develop the electrostatic latent image formed on the photosensitive drum 2 using yellow toner, magenta toner, cyan toner, or black toner, respectively.

[0024] The developing unit 50y includes a developing roller 51y, a supply roller 52y, and a developing blade 55y. As shown in FIG. 2A, the developing units 50y, 50m, 50c, and 50k are formed by developing frame bodies 53y, 53m, 53c, and 53k into a chamber-like configuration with an internal space. The developing roller 51y is a developer carrier that carries toner as a developer, rotates, 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 developing blade 55y is a regulating member that regulates the thickness of the toner layer carried on the developing roller 51y. The other developing units 50m, 50c, and 50k also include similar developing rollers 51m, 51c, and 51k, supply rollers 52m, 52c, and 52k, and developing blades 55m, 55c, and 55k.

[0025] (Rotary configuration) The rotary body 90 is made up of a rotary frame 90f and the developing units 50y, 50m, 50c, and 50k. In other words, the rotary body 90 is made up of the rotary frame 90f and the developing units 50y, 50m, 50c, and 50k assembled thereto.

[0026] Trays 80y, 80m, 80c, and 80k are attached to the rotary body 90. The combination of the rotary body 90 and the trays 80y, 80m, 80c, and 80k can be called the rotary unit 90U. In other words, the rotary unit 90U has the rotary body 90 and the trays 80y, 80m, 80c, and 80k. The rotary body 90 is sometimes called the rotary 90.

[0027] The toner cartridges 70y, 70m, 70c, and 70k are detachably held in trays 80y, 80m, 80c, and 80k, respectively. The toner cartridges 70y, 70m, 70c, and 70k contain toner of the respective colors inside a main body formed by cartridge frames 71y, 71m, 71c, and 71k, respectively.

[0028] The rotary unit 90U with the toner cartridges 70y, 70m, 70c, and 70k attached thereto can be called a rotary assembly 90A.

[0029] The rotary body 90 is rotatable around a rotation axis (rotation center) 90C. The rotation axis 90C coincides with the rotation axes of the rotary frame 90f, the rotary unit 90U, and the rotary assembly 90A. The rotation axis 90C is also substantially parallel to the rotation axis (rotation center) of the photosensitive drum 2.

[0030] The rotary body 90 can take a development position where any one of the development rollers 51y, 51m, 51c, and 51k faces the photosensitive drum 2 by rotating around the rotation axis 90C.

[0031] (development position, replacement position and evacuation position) The apparatus main body 1A is housed in a housing 16, and the housing 16 is provided with an opening 16a for ejecting the tray 80 to the outside of the apparatus and replacing the toner cartridge 70. Furthermore, a door 14 is provided for opening and closing the opening 16a.

[0032] 2(a) is a cross-sectional view of the rotary body 90 and its vicinity when the developing roller 51y is positioned facing the photosensitive drum 2. The rotary body 90 is supported so as to be able to swing about a swing shaft 91. At the development position shown in FIG. 2(a), the rotary 90 is biased by a biasing member (not shown), so that the developing roller 51y abuts against the photosensitive drum 2. When the rotary 90 is rotated clockwise in the drawing and moves to the replacement position for the toner cartridge 70k shown in FIG. 2(b), a spacing mechanism (not shown) causes the rotary 90 to swing about the swing shaft 91, and the developing roller 51y moves away from the photosensitive drum 2.

[0033] As shown in FIG. 2(a), the position where the developing roller 51y faces the photosensitive drum 2 is called the yellow developing position. Similarly, the position where the developing roller 51m faces the photosensitive drum 2 is called the magenta developing position. The position where the developing roller 51c faces the photosensitive drum 2 is called the cyan developing position. The position where the developing roller 51k faces the photosensitive drum 2 is called the black developing position. The rotary body 90 can change the developing roller facing the photosensitive drum 2 by rotating around the rotation axis 90C.

[0034] On the other hand, the rotary body 90 can also take a position where the developing rollers 51y, 51m, 51c, and 51k do not face the photosensitive drum 2 by rotating around the rotation axis 90C.

[0035] FIG. 2(b) shows a cross section of the rotary body 90 and its vicinity, illustrating the state in which a toner cartridge 70K containing black toner is being replaced. At this time, the toner cartridge 70K is stopped in a position facing the opening 16a and door 14 provided in the device main body 1A. This position is called the replacement position for the toner cartridge 70k. When the tray 80k is slid from this replacement position to the outside of the rotary body 90, the user can replace the toner cartridge 70k. This position is called the retracted position for the toner cartridge. In other words, to move a specific toner cartridge 70 between the replacement position and the retracted position, it is not necessary to rotate the rotary body 90; only the sliding movement of the tray 80 is sufficient.

[0036] The position of the toner cartridge 70 housed in the rotary body 90 is sometimes referred to as the mounting position, as opposed to the retracted position where the toner cartridge 70 is located outside the machine. The replacement position and development position are determined by the rotational phase of the rotary body 90, while the mounting position and retracted position are determined by sliding the tray 80. The rotational phase is, for example, a deflection angle in a polar coordinate system with the rotation axis of the rotary body 90 as the origin. For example, the replacement position, development position, or replenishment position (described later) is located in the direction of a predetermined deflection angle with the rotation axis of the rotary body 90 as the origin. The radius vector of these positions is approximately the radius of the rotary body 90. While the term "rotational phase" is used in this embodiment, it may also be referred to as "deflection angle" for the reasons described above. Therefore, for example, a term such as "first rotational phase" may also be referred to as "first deflection angle."

[0037] In this embodiment, the exterior surface of the apparatus main body 1A is formed by the exterior surface of the frame 16. In other words, the outside of the apparatus can also be said to be the outside of the frame 16. Therefore, the retracted position is a position where at least a part of the toner cartridge 70 is outside the apparatus, and can also be said to be a position where at least a part of the toner cartridge 70 protrudes from the opening 16a of the frame 16 of the apparatus main body 1A toward the outside of the frame 16.

[0038] When the door 14 is in the closed position as shown in FIG. 2(b), the opening 16a of the frame 16 of the apparatus main body 1A is covered by the door 14. The exterior surface 14a of the door 14 in the closed position forms part of the exterior surface of the apparatus main body 1A. In this case, the outside of the apparatus refers to the area outside the exterior surface 14a of the door 14 in the closed position. In other words, if the position of the exterior surface 14a of the door 14 in the closed position is defined as the exterior position, then when the toner cartridge 70 is in the retracted position, at least a portion of the toner cartridge 70 is located outside the apparatus main body 1A beyond this exterior position. In other words, at least a portion of the toner cartridge 70 would be located in a space that would be outside the apparatus main body 1A if the door 14 were in the closed position.

[0039] 3, the device main body 1A has a control unit 31 and motors M1, M2, and M3 as drive sources 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 main body 90 about the rotation axis 90C. In other words, the motor M1 rotates the rotary assembly 90A and the rotary unit 90U about the rotation axis 90C.

[0040] The apparatus main body 1A also has a drive device 98 including a motor M2 and a transmission device. The transmission device includes drive racks 15L, 15R and a transmission unit 15t as drive gears, which will be described later. The driving force of the motor M2 is transmitted to the drive racks 15L, 15R by the transmission unit 15t. In other words, the motor M2 is configured to drive the drive racks 15L, 15R, and moves the trays 80y, 80m, 80c, and 80k to insert into or eject from the rotary main body 90 via the drive racks 15L, 15R. The drive racks 15L, 15R are also collectively referred to as drive racks 15.

[0041] 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, belt drive roller 10b, and fixing device 40.

[0042] 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.

[0043] (Toner cartridge replacement operation) Figure 14 shows a cross section of the rotary 90 and its surroundings when replacing a toner cartridge. As shown in Figure 14(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 main body 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.

[0044] As an example of a drive transmission mechanism (not shown), a 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 taking the tray out of the rotary from the replacement position or the retracted position. This configuration will be described with reference to Figs. 11 to 14.

[0045] (Tray arrangement in rotary) 11 and 12, the arrangement of the trays 80y to 80k in the rotary 90 will be described. Fig. 11 is a perspective view showing the arrangement of the trays 80y to 80k in the rotary 90. Fig. 12 is a cross-sectional view showing the arrangement of the trays 80y to 80k in the rotary 90.

[0046] As shown in Fig. 11, trays 80y-80k are provided with toner cartridge holding portions 81y-81k and tray rails 82y-82k, respectively (toner cartridge holding portions 81m-81k are not shown). The tray rails 82y-82k are provided at both ends of the trays, sandwiching the toner cartridge holding portions 81y-81k. Rack portions 821y-821k are formed on the tray rails 82y-82k. Furthermore, rack gears 94y-94k are rotatably held within the rotary 90, and the rack gears 94y-94k are engaged with the rack portions 821y-821k, respectively, so as to transmit driving force.

[0047] 11 and 12, four trays 80y to 80k are arranged in a stacked manner within the rotary 90. The trays are inserted and removed in directions rotated by 90 degrees (in the directions of the arrows in the figures). Therefore, the yellow tray 80y and the cyan tray 80c, and the magenta tray 80m and the black tray 80k are each held so that they can slide in the same direction. Each tray is displaceable between an exchange position where it is housed within the rotary 90 and a retracted position where it is ejected outside the rotary 90.

[0048] (Tray insertion / removal drive configuration) 13 and 14, a drive configuration for inserting and removing trays 80y to 80k arranged in rotary 90 will be described. Fig. 13 is a perspective view showing the drive configuration for inserting and removing trays. Fig. 14 is a cross-sectional view showing the drive configuration for inserting and removing trays.

[0049] FIG. 13(a) shows a state in which tray 80k is inside rotary 90 (i.e., a state in which toner cartridge 70k is attached to development unit 50k). The rotational phase of rotary 90 in which this tray or cartridge position is located is called the first rotational phase. FIG. 13(b) shows a state in which tray 80k has slid outside rotary 90. At this time, door 14 is open. As described above, two rack portions 821k are formed at both ends. Two rack gears 94k and two drive racks 15 are also disposed at positions corresponding to rack portions 821k at both ends. Tray 80k is held relative to rotary 90 so as to be slidable in a direction parallel to tray rail 82k. Drive rack 15 is held relative to image forming apparatus main body 1 so as to be slidable in the vertical direction. While only tray 80k of the four trays 80y-80k is shown here, the drive configuration for inserting and removing trays 80y-80k is similar.

[0050] 14(a) and 14(b), the tray insertion / removal operation for sliding the tray 80k from inside the rotary 90 (the position where the toner cartridge 70k is attached to the developing unit 50k) to the outside will be described. The insertion / removal operation of the tray 80k is performed by a drive source (not shown), a drive rack 15, a rack gear 94k, and a rack portion 821k. First, the drive force transmitted by the drive source 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 position where the toner cartridge 70k is attached to the developing unit 50k toward the outside of the rotary 90. The door 14 may open in conjunction with this operation or may be pushed by the tray 80.

[0051] Furthermore, after replacing the toner cartridge, the operation of sliding the tray 80k into the rotary 90 can be performed by rotating the drive source 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 main body 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 close by itself.

[0052] 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 in the retracted position can be replaced. In the retracted position, the discharge opening 712 (see FIG. 4) of the toner cartridge 70 opens upward relative to the toner cartridge 70. In this state, the receiving opening 532 (see FIG. 4) 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 holding 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.

[0053] (developing unit) The development units 50y, 50m, 50c, and 50k share the same basic structure and function. The toner cartridges 70y, 70m, 70c, and 70k share the same basic structure and function. The trays 80y, 80m, 80c, and 80k also share the same basic structure and function. Therefore, when there is no need to distinguish between them, the subscripts y, m, c, and k are omitted, and the description will refer to any one of the four units, cartridges, and trays. y, m, c, and k represent the color components of the toner, corresponding to yellow, magenta, cyan, and black, respectively.

[0054] 4 is a diagram showing a tray 80, a toner cartridge 70, and a developing unit 50 arranged inside the rotary body 90. FIG. 4 shows a state in which the toner cartridge 70 is installed.

[0055] 4, the toner cartridge 70 has a cartridge frame 71. The cartridge frame 71 has a toner storage section 711 that stores toner, and a discharge opening 712 that communicates with the toner storage section 711.

[0056] The developing unit 50 has a developing frame 53. The developing frame 53 is provided with a developing-side accommodating portion 531 and a receiving opening 532 that communicates with the developing-side accommodating portion 531. The developing unit 50 may be referred to as a developing chamber. The receiving opening 532 of the developing unit 50 and the discharge opening 712 of the toner cartridge 70 may be referred to individually or collectively as simply an opening.

[0057] The developing unit 50 also has a developing roller 51, a supply roller 52, and a developing blade 55, and the developing blade 55 is positioned to abut against the developing roller 51 so as to regulate the thickness of the toner layer carried by the developing roller 51.

[0058] 4, when the toner cartridge 70 is attached and in the attached position relative to the developing frame 53, the discharge opening 712 of the toner cartridge 70 is positioned opposite the receiving opening 532 of the developing unit 50. In other words, the storage section 711 of the toner cartridge 70 and the developing-side storage section 531 of the developing unit 50 communicate with each other via the discharge opening 712 and the receiving opening 532.

[0059] This allows the toner stored in the storage portion 711 of the toner cartridge 70 to move to the development-side storage portion 531 of the developing unit 50. When the toner cartridge 70 is positioned above the developing unit 50, the discharge opening 712 and the receiving opening 532 are positioned below the storage portion 711 inside the toner cartridge 70. Therefore, the toner stored in the storage portion 711 flows into the development-side storage portion 531 by gravity, and toner is replenished.

[0060] The discharge opening 712 provided in the cartridge 70 and the receiving opening 532 provided in the developing unit 50 may be provided in the area where the toner storage section 711 and the developing frame body 53 are close to each other, and the number, arrangement, and size of both openings (discharge opening 712, receiving opening 532) may be adjusted as appropriate.

[0061] With regard to the toner cartridge 70, it is desirable that the discharge opening 712 be covered with a sealing member to prevent the toner stored therein from leaking out when the toner cartridge 70 is not installed in the developing unit 50. Similarly, with regard to the developing unit 50, it is desirable that the receiving opening 532 be covered with a sealing member to prevent the toner stored therein from leaking out when the toner cartridge 70 is not installed. It is also desirable to provide a check valve or the like at the opening to prevent toner supplied from the toner cartridge 70 to the developing unit 50 from flowing back into the toner cartridge 70. Note that if a check valve is provided in the developing unit 50, the sealing member for the receiving opening 532 may not be necessary. Furthermore, because the discharge opening 712 faces and communicates with the receiving opening 532 except when the toner cartridge 70 is being replaced, sealing and unsealing of the tray 80 may be performed manually.

[0062] (supply position) 5 is a diagram showing the tray 80, toner cartridge 70, and developing unit 50 arranged inside the rotary body 90 at different angles of the rotary body 90. As described above, toner is supplied to the developing unit 50 of this embodiment by gravity through the discharge opening 712 and the receiving opening 532.

[0063] The effective opening is defined as the opening area that is effective for toner supply when the discharge opening 712 and the receiving opening 532 are connected. It can be said that the wider the effective opening, the more toner can be supplied when the projection direction when projected vertically from the storage section 711 toward the discharge opening 712 is downward and the wider the projected effective opening.

[0064] Comparing the widths La, Lb, and Lc of the openings projected vertically in Figures 5(a), 5(b), and 5(c), it can be seen that width Lb is the widest, and that the largest amount of toner can be replenished at this angle of the developing unit 50. The vertical projection of the length of the opening in the depth direction of Figure 5 (downward in the figure) does not change depending on the rotational phase of the rotary 90. Therefore, when the vertically projected width reaches maximum width Lb, the vertically projected area of ​​the opening is also maximized. In this case, the opening must be oriented vertically downward as viewed from the storage chamber 711 inside the toner cartridge 70. In this state, the largest amount of toner can be replenished from the toner cartridge 70 to the developing unit 50. When the opening 712 of the toner cartridge 70 is projected vertically downward as viewed from the storage chamber 711, this state is sometimes simply referred to as "downward facing." Figure 5(c) shows the state of the developing unit 50, for example, when the developing unit 50 is performing development (i.e., when the developing roller 51 develops the latent image formed on the photosensitive drum 2). In this state, the opening of the toner cartridge 70 faces vertically downward, but its projected area is smaller than the vertical projected area of ​​the opening of the toner cartridge 70 in the state of Figure 5(b).

[0065] Toner, being a powder, is not as fluid as liquid, and so "bridge-like" clogging can occur. The angle shown in FIG. 5(b) is optimal from the viewpoint of avoiding this. The position shown in FIG. 5(b), which allows the rotary body 90 to replenish the most toner efficiently within its rotatable range, is defined as the "replenishment position." That is, the rotational phase of the rotary 90 at which the area of ​​the discharge opening 712 projected vertically downward from the storage section 711 of the toner cartridge 70 is maximized, is called the replenishment position. In this embodiment, four development units 50 are provided on the rotary 90, and a replenishment position is determined for each development unit 50 and toner cartridge 70.

[0066] (Image formation operation) The image forming operation in this embodiment will be described with reference to FIGS. 1 and 2(a). When a video controller 30 receives image information from an external device (not shown) such as a host computer, it sends a print signal to a control unit 31, and the image forming operation begins. First, in a standby position, the photosensitive drum 2 is rotated in the direction of the arrow in FIG. 1 (counterclockwise) in synchronization with the rotation of the intermediate transfer belt 10a. Then, the surface of the photosensitive drum 2 is uniformly charged by a charging roller 3.

[0067] When a color image is formed on the sheet S, the rotary body 90 rotates in the direction of the arrow in Figure 1 (clockwise) while supporting the developing units 50y, 50m, 50c, and 50k, as follows: 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.

[0068] First, the scanner 4 irradiates the photosensitive drum 2 with laser light based on image data corresponding to a yellow (y) 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 motor M1 rotates the rotary body 90, causing the rotary body 90 to assume a yellow developing position. When the rotary body 90 assumes the yellow developing position, the developing roller 51y is in the developing position, and develops the electrostatic latent image formed on the photosensitive drum 2 with yellow toner.

[0069] 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 system. However, each of the developing rollers 51y, 51m, 51c, and 51k may also develop an electrostatic latent image while a gap is provided between the developing rollers 51y, 51m, 51c, and 51k and the photosensitive drum 2 at the developing position. In other words, the image forming apparatus 1 may employ a non-contact development system.

[0070] 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.

[0071] Thereafter, the rotary body 90 is rotated to move the developing rollers 51m, 51c, and 51k to the developing positions in order, 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, and a magenta toner image is formed on the intermediate transfer belt 10a. 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.

[0072] Then, the 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, until the color image is formed on the intermediate transfer belt 10a, the secondary transfer roller 12 and the cleaning device 13 are not in contact with the intermediate transfer belt 10a.

[0073] Meanwhile, sheets S are fed by a pickup roller 310 from a sheet storage unit 300 provided at the bottom of the apparatus main body 1A. The sheets S are 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 sheets 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) onto the surface of the conveyed sheet S.

[0074] 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.

[0075] (Operation when replacing toner cartridge) In the rotary development type image forming apparatus shown in this embodiment in which the toner cartridge 70 is detachable, there may not be a sufficient amount of toner in the developing unit 50 immediately after replacing the toner cartridge 70. When the user replaces the toner cartridge 70, this is usually triggered by a notification from the image forming apparatus urging the user to replace the toner cartridge 70, or by the user recognizing a toner shortage from an output image. In these cases, the amount of toner in the developing unit 50 is often already low. Therefore, it is preferable to perform a replenishment operation promptly after replacing the toner cartridge 70.

[0076] Therefore, in this embodiment, after replacing the toner cartridge 70, and before developing, a replenishing operation is performed in which the rotary rotates past the replenishing position at least once, preferably multiple times.

[0077] The effect of the replenishment operation, that is, the amount of toner replenished to the developing unit 50, was evaluated as follows.

[0078] Since the amount of toner in the development unit 50 after replenishment is perceived by the user as the number of high-print images that can be printed continuously during actual use, we decided to compare how many images with a print rate of 50% (a solid image printed on the upper half of an A4 sheet) can be output continuously.

[0079] First, as a preliminary experiment, the number of printable sheets when the developer-side storage compartment 531 of the developing unit 50 is filled to the maximum with toner (when the developing unit 50 is full) is determined. Here, single-sided printing is assumed, and this can also be referred to as the number of printable pages. Since the number of printable sheets is expected to vary depending on the paper size, a predetermined paper size, such as A4 size, is used. Furthermore, it is desirable to form images using only toner of a specific color component. This is because, as shown in FIG. 1 and other figures, the toner cartridge 70 of this embodiment has different capacities for black and other colors. Furthermore, because image formation using toner of multiple color components requires the rotary 90 to rotate, this rotation also prevents a newly installed toner cartridge 70 from passing the replenishment position more than a predetermined number of times.

[0080] 6 shows the number of pages that can be continuously printed with a 50% coverage image when a toner cartridge 70 filled to the brim with toner is attached to the developing unit 50, and the rotary body 90 is rotated to pass the replenishment position, and this replenishment operation is performed N times. From this result, it can be seen that even after three or more replenishment operations, the number of pages that can be continuously printed is saturated at 20, which indicates the limit of the amount of toner that can be filled into the developing unit 50 (i.e., when the developing unit 50 is almost full). In other words, if the developing unit 50 is almost full, then when printing an image with a 50% coverage on paper of a predetermined size, 20 pages can be continuously printed.

[0081] The following comparative study was carried out using the supplying operation carried out in this embodiment. As a comparative example 1, after the toner cartridge 70 was installed, image formation was performed without performing the replenishing operation of rotating the rotary 90 to pass the replenishing position. In Example 1-1, after the toner cartridge 70 is mounted, the rotary 90 is rotated to pass the replenishing position once (replenishing operation 1). In Example 1-2, after the toner cartridge 70 was installed, the rotary 90 was rotated to pass the supply position three times (supply operation 2).

[0082] In each of the above cases, a comparison was made as to how many images with a print ratio of 50% could be continuously output onto a given size of paper.

[0083] Specific movement of the developing unit 50 in Comparative Example 1 is shown in Figure 7. In Comparative Example 1, the toner cartridge 70 is installed at the "toner cartridge replacement position" shown in Figure 7. Thereafter, the rotary body 90 rotates in the direction of the arrow (counterclockwise), and the installed toner cartridge 70 moves to the "developing position" shown in Figure 7, where development is performed.

[0084] Specific movement of the developing unit 50 in Example 1-1 is shown in Figure 8. The toner cartridge 70 is installed at the "toner cartridge replacement position" shown in Figure 8. The rotary body 90 then rotates in the direction of the arrow (clockwise) and moves to the "developing position" shown in Figure 8, where development is performed. While moving from the "toner cartridge replacement position" to the "developing position" and performing development, the developing unit 50 passes through the supply position once.

[0085] In Example 1-2, the rotary body 90 is rotated further from the state in which the toner cartridge 70 is in the "developing position" in Example 1-1, and the developing unit 50 passes the supply position three times before development is performed. Specifically, in Example 1-1, from the state in which the toner cartridge 70 is in the "developing position," the rotary 90 is rotated two more times clockwise in Figure 8 to move the toner cartridge 70 to the developing position again and perform development.

[0086] The results of the comparison are shown in Table 1.

[0087] [Table 1]

[0088] When printing was started immediately after replacing the toner cartridge in Comparative Example 1, the number of images with a 50% print rate that could be printed continuously was 1. Considering that 20 images can be printed continuously when the development unit 50 is full, in Comparative Example 1, there is a high possibility that image defects such as insufficient density will occur when the user outputs an image with a high print rate.

[0089] In contrast, in Example 1-1, where the supply operation was performed by passing the supply position once before printing, seven sheets could be printed continuously, and in Example 1-2, where the supply operation was performed by passing the supply position three times, 20 sheets could be printed continuously.

[0090] Even with only one pass through the supply position, seven pages can be printed compared to one page in Comparative Example 1, indicating that the development unit 50 is being replenished. Furthermore, if the supply position is passed three times, the replenishment of the development unit 50 can be considered nearly complete. Although not shown in Table 1, as can be seen from FIG. 6, two passes through the supply position results in a continuous printable number of approximately 15 pages. The continuous printable number is twice or more the number of pages possible in Example 1-1. While this does not necessarily mean that replenishment is complete, it can be said that a considerable amount of toner has been filled into the development unit 50. Note that passing through the supply position three times is the result of this embodiment, in which the maximum amount of toner can be filled into the development unit 50. This result is likely to vary depending on the capacity of the storage compartment 53 of the development unit 50 and the size of the effective opening between the toner cartridge 70 and the development unit 50, among other factors. However, as in FIG. 6, it is naturally expected that there will be a saturation point at which the continuous printable number of pages remains unchanged even if the number of replenishments is increased. The number of replenishments when this saturation point is reached is referred to as the saturation replenishment number.

[0091] As described above, when development is performed for the first time using the toner cartridge 70 after replacing the toner cartridge 70, the toner shortage in the development unit can be compensated for and resolved by performing the replenishing operation of passing the replenishing position. Alternatively, if the toner cartridge 70 is replaced, the replenishing operation of passing the replenishing position may be performed immediately after the replacement.

[0092] In particular, by passing the replenishment position multiple times immediately after replacing the toner cartridge during the replenishment operation, for example by rotating the rotary 90 multiple times, the amount of toner filled into the developing unit 50 can be further increased. Desirably, if the number of replenishment times is at least the saturation replenishment number, the maximum amount of toner can be filled into the developing unit 50. Furthermore, as shown in Figure 6, if the number of replenishment times is two or more, the amount of toner filled into the developing unit 50 will increase, so if the number of replenishment times is two or more but less than the saturation replenishment number, the effect of increasing the amount of toner filled according to the number of replenishment times can be obtained.

[0093] The toner cartridge replacement position and development position shown in Figures 7 and 8 are determined according to the phase (rotational phase or deflection angle) of the rotary 90. If a specific toner cartridge is focused on and called the first cartridge, the rotational phase of the rotary 90 corresponding to the toner cartridge replacement position shown in Figures 7 and 8 may be called the first rotational phase, and the rotational phase of the rotary 90 corresponding to the development position may be called the second rotational phase. Similarly, the rotational phase of the rotary 90 corresponding to the replenishment position may be called the third rotational phase. These may also be called the first deflection angle, the second deflection angle, and the third deflection angle, respectively.

[0094] (Example of control procedure) 15 shows an example of a control procedure at the start of image forming processing by the control unit 3. This procedure is realized by the CPU (processor) 311 of the control unit 3 reading and executing a program stored in the memory 312.

[0095] When any of the toner cartridges 70 is replaced, the control unit 3 stores the fact that it has been replaced and whether the replaced toner cartridge is toner cartridge 70y, 70m, 70c, or 70k. This storage is maintained until development (image formation) is performed using the replaced and newly installed toner cartridge 70, and is erased when development is performed.

[0096] The control unit 3 receives a print job and performs preprocessing necessary for image formation, such as rendering the print job, before starting the image formation process. At this time, it first determines whether the toner cartridge for which the first image formation is performed since replacement is stored (S1501). If a matching toner cartridge is found, the rotary body 90 is rotated a predetermined number of times (S1502). This predetermined number of rotations may be the number of times that the newly installed toner cartridge 70 passes through the supply position. In this embodiment, this predetermined number of times is two or more. Let's assume that the rotary body 90 is rotated clockwise as shown in FIG. 2. If the newly installed toner cartridge 70 is in the replacement position, the rotary body 90 is rotated once, and then the newly installed toner cartridge 70 is moved to the development position. This toner cartridge passes through the supply position twice. In other words, the third rotation phase of the rotary described above is passed twice. In other words, in this case, the rotary body 90 is rotated "(number of times passing the supply position) - 1" times. After this, the newly installed toner cartridge 70 is moved to the development position for development, and then passes through the supply position once more to move to the development position. Specifically, if the predetermined number of times to pass through the supply position is three, then in S1502, the rotary body 90 should rotate two times.

[0097] Thereafter, image formation is started (S1503). At this time, image formation may be performed for each color component in a predetermined order, for example, in the order of ymck.

[0098] In addition, in S1501, it is determined whether or not this is the first image formation after the toner cartridge has been replaced, but other conditions (predetermined conditions) may also be satisfied. In that case, S1502 is executed if the control unit 3 determines that the predetermined conditions are satisfied. The conditions may be, for example, the first image formation after the image forming apparatus has recovered from a jam (fault), or the first image formation after recovering from a sleep state that has lasted a long time (predetermined time).

[0099] Alternatively, the condition "first image formation" may be excluded from the condition of S1501. In other words, S1502 may be executed when a predetermined condition is met, such as the toner cartridge 70 being replaced, the image forming apparatus recovering from a jam (fault), or recovering from a sleep state that lasted a long time (a predetermined time). In S1502, the rotary body 90 is rotated a predetermined number of times. In this case, image formation may be performed in S1503 if there is a job to be processed.

[0100] Furthermore, the number of rotations of the rotary body 90 in S1502 may be variable. The number of rotations refers to the number of times the rotary body 90 rotates around its axis (i.e., the number of revolutions), and may also be referred to as the number of revolutions. The number of rotations may be specified by an administrator, or, if FIG. 15 is started in conjunction with the execution of a received job (print job), the number of rotations before development (the number of rotations in S1502) may be varied depending on the number of prints made by the received job. For example, a threshold may be set for the number of prints made by the job, and the rotary body 90 may be rotated a first predetermined number of times if the number of prints is equal to or greater than a first threshold and less than a second threshold, and may be rotated a second predetermined number of times if the number of prints is equal to or greater than a second threshold and less than a third threshold.

[0101] Furthermore, in the case of full-color printing, the rotary body 90 must rotate to print even one page. Therefore, it is considered that the toner cartridge 70 passes the replenishment position for each page of image formation. Therefore, the above-mentioned predetermined condition may be that the job to be executed or the print job currently being executed is a job that forms a monochrome image using only toner of a specific color component, such as printing a black-and-white image. The toner of a specific color component refers to the toner supplied by a newly installed toner cartridge 70. Monochrome images include not only black, but also images containing only yellow, cyan, or magenta. In such cases, multiple pages of image formation may be performed consecutively without the rotary body 90 rotating. If there is insufficient toner in the development unit 50, the resulting images may be defective. Therefore, by rotating the rotary body 90 in S1502 prior to image formation, defective image formation can be prevented. [Embodiment 2] In the first embodiment, the rotary body 90 is rotated clockwise to move to the replenishment position, but in this embodiment, the rotary body 90 is rotated counterclockwise to move to the replenishment position. Figure 9 shows the specific movement of the developing unit 50 in this embodiment.

[0102] 9, after the toner cartridge 70 is installed at the "toner cartridge replacement position," when development using the toner cartridge 70 is performed for the first time, the rotary body 90 is rotated in the direction of the arrow (counterclockwise). After passing through the development position once and then the supply position, the rotary body 90 reaches the development position and performs development.

[0103] This embodiment is similar to the first embodiment in that toner is replenished to the developing unit 50 by passing through the replenishment position, but compared to the first embodiment, more toner is replenished near the supply roller 52. By replenishing toner near the supply roller 52, mixing of the toner in the developing unit 50 and the toner cartridge 70 is further promoted. This makes it possible to prevent fogging caused by insufficient mixing of new and old toner.

[0104] 10A is a diagram showing the postures of the toner cartridge 70 and the developing unit 50 at different angles during the supply process passing the supply position in this embodiment, and the amount of toner in the toner cartridge 70 at that time. In other words, it shows the postures of the toner cartridge 70 and the developing unit 50 before and after the supply position when the rotary body 90 rotates counterclockwise and passes the supply position.

[0105] 10(b) is a diagram showing the postures of the toner cartridge 70 and the developing unit 50 at different angles during the supply process passing the supply position in the first embodiment, and the amount of toner in the toner cartridge 70 at that time. In other words, it shows the postures of the toner cartridge 70 and the developing unit 50 before and after the supply position when the rotary body 90 rotates clockwise and passes the supply position.

[0106] In this embodiment, toner is replenished from the toner cartridge 70 to the developing unit 50 by changing its position in the order of a1 → a2 → a3, while in the first embodiment, toner is replenished by changing its position in the order of b1 → b2 → b3. Positions a2 and b2 are the positions at the respective "replenishment positions," but toner is also replenished to the developing unit 50 in positions before and after them.

[0107] The amount of toner in the toner cartridge 70 decreases as the toner is replenished, so that in the first half of the replenishment process, a1 and b1, the amount is relatively large, and a3 and b3 are relatively small.

[0108] The amount of toner supplied to the developing unit 50 is roughly proportional to the amount of toner in the toner cartridge 70, and the more toner that can be supplied, the greater the amount of toner that can be supplied.

[0109] In this embodiment, in the first half of the replenishment process when the amount of toner in the toner cartridge 70 is relatively large, the rotary body 90 is rotated counterclockwise to perform the replenishment operation so that the supply roller 52 is located directly below the opening area effective for toner replenishment when the discharge opening 712 and the receiving opening 532 are connected.

[0110] This allows more toner to be supplied to the vicinity of the supply roller 52 than in the first embodiment, and promotes mixing of the toner in the developing unit 50 with the toner cartridge 70. In fact, an image was formed immediately after replacing the toner cartridge 70, and the fog on the first sheet of the image was compared with that in the first embodiment.

[0111] The fogging on paper was measured using a REFLECTMETER MODEL T-6DS manufactured by Tokyo Denshoku Co., Ltd. A green filter was used and the fogging was calculated according to the following formula:

[0112] Fog (reflectance) (%) = reflectance on standard paper (%) - reflectance of non-image area of ​​sample (%) If the fog on the paper is 2.0% or less, it can generally be said that the image is good.

[0113] As a result of measuring the fogging on paper, the fogging was 0.8% in the first embodiment, while it was 0.5% in this embodiment. In both cases, the fogging is at a level that is not a problem compared to the 2% that is a practical problem, but this embodiment has a larger margin and can be said to be more advantageous in terms of fogging than the first embodiment.

[0114] That is, in this embodiment, during the first image forming operation after replacing the toner cartridge 70, or immediately after replacement, the rotary 90 is rotated, for example, counterclockwise in FIG. 2, so that the toner cartridge 70 moves from the replacement position to the development position, passing through the replenishment position. The counterclockwise rotation is the direction in which the toner cartridge 70, which is in the replacement position, moves upward at the beginning of the rotation of the rotary 90, passing through the development position and then reaching the replenishment position. The rotary 90 then rotates further through the replenishment position, and reaches the development position again. Development is performed at that position. As described in the first embodiment, it is more effective to pass through the replenishment position as many times as possible, up to the saturation replenishment number. Therefore, in this embodiment, the rotary 90 may also be controlled to rotate so that it passes through the replenishment position multiple times.

[0115] In this embodiment, the control procedure at the start of development by the control unit 3 is almost the same as that shown in FIG. 15. However, the number of rotations of the rotary in S1502 differs from that in the first embodiment. In the first embodiment, when a newly installed toner cartridge 70 is in the replacement position, the rotary body 90 is rotated "number of times passing the supply position - 1" times in S1502. However, in this embodiment, the toner cartridge 70 moving from the replacement position to the development position does not pass through the supply position. Therefore, in this embodiment, the rotary body 90 is rotated the same number of times as the "number of times passing the supply position" in S1502.

[0116] By controlling in this manner, even in this embodiment, after replacing the toner cartridge 70, the toner cartridge 70 can be made to pass the replenishment position a predetermined number of times prior to the first development using the newly installed toner cartridge 70.

[0117] [Other Examples] Although the present invention has been described above with reference to specific examples, the present invention is not limited to the above-described embodiments.

[0118] In the first and second embodiments, the supply operation is described in which the rotary body 90 is rotated clockwise and counterclockwise to pass the supply position. After replacing the toner cartridge 70, the supply operation may be performed by combining clockwise and counterclockwise rotation directions of the rotary body 90 as long as the rotary body 90 passes the supply position.

[0119] 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.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0120] Summary of embodiments The above embodiments can be summarized as follows: (Item 1) An image forming apparatus in which a cartridge containing a developer can be detachably mounted, a rotary including a developing unit capable of accommodating the cartridge attached thereto and configured to accommodate the developer supplied through an opening of the cartridge; a drive unit that rotates the rotary; a control unit that controls the drive unit, the control unit controls the drive unit to rotate the rotary to a first rotation phase at which the cartridge can be replaced when the cartridge is replaced, and to rotate the rotary to a second rotation phase at which the development is performed by the development unit when an image is developed using the developer supplied from the cartridge and contained in the development unit; When the control unit determines that a predetermined condition is satisfied, if it is the first image forming operation after the cartridge has been replaced, the control unit controls the drive unit to rotate the rotary from the first rotation phase to the second rotation phase through a third rotation phase in which the opening of the cartridge is projected downward along a vertical direction as seen from inside the cartridge a plurality of times. An image forming apparatus characterized by: (Item 2) Item 1, the image forming apparatus according to item 1, In the first rotation phase, the opening of the replaced cartridge faces upward; In the second rotational phase, the area of ​​the opening of the cartridge projected in the vertical direction is smaller than the area of ​​the opening of the cartridge projected in the vertical direction in the third rotational phase. An image forming apparatus characterized by: (Item 3) Item 1 or 2, the image forming apparatus, In the first rotational phase, the opening of the cartridge faces upward; When the control unit determines that the predetermined condition is satisfied, the control unit controls the drive unit to rotate the rotary in the first rotation phase a plurality of times. An image forming apparatus characterized by: (Item 4) 4. The image forming apparatus according to any one of items 1 to 3, In the first rotational phase, the opening of the cartridge faces upward; When the control unit determines that the predetermined condition is satisfied, the control unit controls the drive unit to rotate the rotary from the first rotation phase to the second rotation phase, and then to the third rotation phase, and then further rotates the rotary. An image forming apparatus characterized by: (Item 5) 5. The image forming apparatus according to any one of items 1 to 4, The control unit changes the number of rotations of the rotary depending on the print job to be executed or the number of prints to be printed by the print job being executed. An image forming apparatus characterized by: (Item 6) 6. The image forming apparatus according to any one of items 1 to 5, The predetermined condition includes that the cartridge has been replaced. An image forming apparatus characterized by: (Item 7) Item 6. The image forming apparatus according to item 6, The predetermined condition includes that the print job to be executed or the print job currently being executed is a print job for forming a monochrome image using developer supplied by the replaced cartridge. An image forming apparatus characterized by: (Item 8) 8. The image forming apparatus according to any one of items 1 to 7, The rotary can accommodate a plurality of cartridges containing developer, including the cartridge, and includes a plurality of developing units configured to contain the developer supplied through openings of the plurality of cartridges. An image forming apparatus characterized by: (Item 9) Item 9. The image forming apparatus according to any one of items 1 to 8, The number of times is at most the number of times of saturation replenishment at which the number of printable sheets that can be continuously developed and printed with toner supplied from the replaced cartridge does not increase even if the number of times of passing through the third rotation phase is increased. An image forming apparatus characterized by:

[0121] The present 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. Therefore, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0122] 1 image forming apparatus, 1A apparatus main body, 2 photosensitive drum, 3 charging roller, 4 scanner, 6 cleaning unit, 50 developing unit, 51 developing roller, 52 supply roller, 53 developing frame, 531 developing side storage section, 532 receiving opening, 55 developing blade, 70 toner cartridge, 71 cartridge frame, 711 storage section, 712 discharge opening, 80 tray, 90 rotary

Claims

1. An image forming apparatus in which a cartridge containing a developer can be detachably mounted, a rotary including a developing unit capable of accommodating the cartridge attached thereto and configured to accommodate the developer supplied through an opening of the cartridge; a drive unit that rotates the rotary; a control unit that controls the drive unit, the control unit controls the drive unit to rotate the rotary to a first rotation phase at which the cartridge can be replaced when the cartridge is replaced, and to rotate the rotary to a second rotation phase at which development is performed by the development unit when an image is developed using the developer supplied from the cartridge and contained in the development unit; When the control unit determines that a predetermined condition is satisfied, and when a first image forming operation is to be performed after the cartridge has been replaced, the control unit controls the drive unit to rotate the rotary from the first rotation phase to the second rotation phase via a third rotation phase in which the opening of the cartridge is projected downward along a vertical direction as viewed from inside the cartridge a plurality of times. An image forming apparatus characterized by:

2. 2. The image forming apparatus according to claim 1, In the first rotation phase, the opening of the replaced cartridge faces upward; In the second rotational phase, the area of ​​the opening of the cartridge projected in the vertical direction is smaller than the area of ​​the opening of the cartridge projected in the vertical direction in the third rotational phase. An image forming apparatus characterized by:

3. 2. The image forming apparatus according to claim 1, In the first rotational phase, the opening of the cartridge faces upward; When the control unit determines that the predetermined condition is satisfied, the control unit controls the drive unit to rotate the rotary in the first rotation phase a plurality of times. An image forming apparatus characterized by:

4. 2. The image forming apparatus according to claim 1, In the first rotational phase, the opening of the cartridge faces upward; When the control unit determines that the predetermined condition is satisfied, the control unit controls the drive unit to rotate the rotary, which is in the first rotation phase, to the second rotation phase, and then to the third rotation phase, and then further rotates the rotary. An image forming apparatus characterized by:

5. 2. The image forming apparatus according to claim 1, The control unit changes the number of revolutions of the rotary depending on the print job to be executed or the number of sheets to be printed by the print job being executed. An image forming apparatus characterized by:

6. 2. The image forming apparatus according to claim 1, The predetermined condition includes that the cartridge has been replaced. An image forming apparatus characterized by:

7. 7. The image forming apparatus according to claim 6, The predetermined condition includes that the print job to be executed or the print job currently being executed is a print job for forming a monochrome image using developer supplied by the replaced cartridge. An image forming apparatus characterized by:

8. 2. The image forming apparatus according to claim 1, The rotary can accommodate a plurality of cartridges containing developer, including the cartridge, and includes a plurality of developing units configured to contain the developer supplied through openings of the plurality of cartridges. An image forming apparatus characterized by:

9. 2. The image forming apparatus according to claim 1, The number of times is at most the number of saturation replenishment times at which the number of printable sheets that can be continuously developed and printed with toner supplied from the replaced cartridge does not increase even if the number of times the third rotation phase is increased. An image forming apparatus characterized by:

Images