Image forming device

Abstract

To enable prevention of a reduction in productivity and efficient use of a recovery developer container even when the recovery developer container is removed while recovery developer is conveyed.SOLUTION: In an image forming apparatus 100, when a control unit 150 detects that a first container 10L is removed while recovery developer is conveyed to the first container 10L during an image forming operation, it controls a conveying device 1 to stop the conveyance of the recovery developer to the first container 10L and not to perform conveyance of the recovery developer to a second container 10R, and controls an image forming unit G to continue the image forming operation, and when the control unit detects that the first container 10L is attached within a predetermined time from the detection of the removal, it can control the conveying device 1 to resume the conveyance of the recovery developer to the first container 10L.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a plurality of functions among these, which uses an electrophotographic system or an electrostatic recording system. [Background technology]

[0002] In conventional image forming apparatuses, such as electrophotographic copying machines, a toner image formed on a photoconductor (image carrier) using a developer containing toner by an electrophotographic image formation process is transferred to a transfer medium such as a recording medium. When the toner image is transferred from the photoconductor to the transfer medium, residual toner (transfer residual toner) remaining on the photoconductor is removed from the photoconductor by a cleaning unit and transported to a recovered developer container by a developer recovery device as recovered developer, where it accumulates. When the recovered developer container becomes full, it is replaced with an empty recovered developer container. Conventionally, replacing a recovered developer container requires stopping the image formation operation of the image forming apparatus in order to stop the developer recovery device from transporting the recovered developer. Therefore, in operations requiring continuous, large-volume printing, for example, replacing the recovered developer container reduces productivity.

[0003] To address this issue, a configuration has been proposed in which two recovered developer containers are detachably mounted on the main body of an image forming apparatus, and the recovered developer is selectively discharged from one of two discharge sections that discharge the recovered developer to each recovered developer container (Patent Document 1). In the configuration described in Patent Document 1, an agitator having a rotating shaft with multiple blades radially attached thereto is disposed within an agitator tank into which the recovered developer is fed, and the multiple blades form multiple chambers that accommodate the recovered developer. The agitator rotates so that the multiple chambers of the agitator tank sequentially pass through two openings provided in the agitator tank that communicate with the two discharge sections, respectively, thereby discharging the recovered developer from the agitator tank. Of the two discharge sections arranged side by side in the left-right direction, the agitator rotates clockwise when discharging the recovered developer from the right discharge section, and rotates counterclockwise when discharging the recovered developer from the left discharge section. According to this configuration, when replacing one of the recovered developer containers, if the other recovered developer container is in a state where recovered developer can be recovered, one of the recovered developer containers can be replaced without stopping the image formation operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-83102 Summary of the Invention [Problem to be solved by the invention]

[0005] However, an image forming apparatus equipped with a developer recovery device capable of switching the destination of recovered developer as described in Patent Document 1 has the following problems.

[0006] For example, when recovered developer is being transported to the first of the first and second recovered developer containers and the second recovered developer container is full and inside the device body, it is conceivable that the first recovered developer container may be inadvertently pulled out of the device body. In such a case, immediately stopping the image formation operation of the image forming apparatus could impede productivity. This also applies if, for example, the first of the first and second recovered developer containers is inadvertently pulled out of the device body while recovered developer is being transported to the first of the first and second recovered developer containers. Furthermore, when recovered developer is being transported to the first of the first and second recovered developer containers and the second recovered developer container is empty and inside the device body, it is conceivable that the first recovered developer container may be inadvertently pulled out of the device body. In such a case, if the destination of the recovered developer is immediately switched to the second recovered developer container, depending on the remaining amount that can be filled in the first recovered developer container, this may hinder efficient use of the recovered developer container.

[0007] Therefore, it is conceivable to provide a structure such as a locking means for preventing (locking) the recovered developer container, in which the recovered developer is transported, from being inadvertently pulled out, as described in Patent Document 1. However, such a structure leads to the complication of the device and an increase in costs, so it is desirable to omit or simplify it.

[0008] In the above, the recovered developer has been described as being transfer residual toner removed from a photosensitive member, but the recovered developer generated in an image forming apparatus is not limited to this. For example, the recovered developer may be transfer residual toner removed from an intermediate transfer member serving as a second image carrier that is transported for secondary transfer of a toner image primarily transferred from a photosensitive member serving as a first image carrier to a recording material. Furthermore, for example, the recovered developer may be developer (which may include toner and carrier) discharged from a developing device that develops an electrostatic image formed on an image carrier.

[0009] Therefore, an object of the present invention is to suppress a decrease in productivity and enable efficient use of a recovered developer container even when the recovered developer container to which the recovered developer is being transported is removed. [Means for solving the problem]

[0010] The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides an image forming unit that forms a toner image, a first storage container that is detachably provided and that stores the remaining toner discharged from the image forming unit, a second storage container that is detachably provided and that stores the remaining toner discharged from the image forming unit, a transport device that can transport the remaining toner discharged from the image forming unit to the first storage container and the second storage container, a first installation detection unit that detects the installation of the first storage container, a second installation detection unit that detects the installation of the second storage container, and a transport device that transports the remaining toner discharged from the image forming unit to the first storage container and the second storage container. a control unit capable of controlling the conveying device based on detection results of the first attachment detection unit, the second attachment detection unit, the first full detection unit, and the second full detection unit, and when an image forming operation is being performed in a state in which residual toner is being conveyed to the first storage container by the conveying device, the control unit determines that the first storage container is not full based on detection results of the first attachment detection unit and the first full detection unit. and, The first container has been removed. Bothand (ii) when it is detected based on the detection result of the first mounting detection unit that the first storage container has been reattached, the control unit controls the conveying device to stop conveying the remaining toner to the first storage container and controls the image forming unit to continue the image forming operation. [Effects of the Invention]

[0011] According to the present invention, even when the recovered developer container in which the recovered developer is being transported is removed, it is possible to suppress a decrease in productivity and enable efficient use of the recovered developer container. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Figure 2] 5A and 5B are schematic diagrams illustrating a manner in which recovered developer is discharged from an image forming unit. [Figure 3] FIG. 2 is a schematic perspective view of an image forming apparatus showing a manner in which a recovered developer container is attached. [Figure 4] FIG. [Figure 5] FIG. 2 is a perspective view of a developer recovery device. [Figure 6] FIG. 5 is a cross-sectional view taken along line XX in FIG. 4. [Figure 7] 5 is a cross-sectional view taken along line YY in FIG. 4. [Figure 8] FIG. 2 is a perspective view of a part of the developer recovery device with the recovered developer container removed. [Figure 9] FIG. 2 is a perspective view of the developer recovery device for explaining a developer recovery operation. [Figure 10] FIG. 2 is a perspective view of the developer recovery device for explaining a developer recovery operation. [Figure 11] FIG. 4 is a schematic block diagram showing a control mode of the developer recovery device. [Figure 12] FIG. 4 is a flowchart of the basic operation of the developer recovery device. [Figure 13] FIG. 4 is a flowchart of the basic operation of the developer recovery device. [Figure 14] FIG. 10 is a flowchart of a specific operation when a collected developer container to which a collected developer is to be transported is detached. [Figure 15] FIG. 10 is a flowchart of a specific operation when a collected developer container to which a collected developer is to be transported is detached. [Figure 16] FIG. 10 is a perspective view of a developer recovery device according to another embodiment. [Figure 17] FIG. 10 is a schematic diagram of a part of a developer recovery device according to another embodiment. [Figure 18] FIG. 2 is a front view of an operation unit of the image forming apparatus. [Figure 19] FIG. 2 is a front view showing the periphery of a container mounting portion of the image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0013] The image forming apparatus according to the present invention will be described in more detail below with reference to the drawings.

[0014] [Example 1] 1. Image forming device 1 is a schematic cross-sectional view (a cross-section substantially perpendicular to the direction of the rotation axis of a photosensitive drum 101, which will be described later) of an image forming apparatus 100 according to this embodiment. The image forming apparatus 100 according to this embodiment is a tandem printer employing an intermediate transfer method, capable of forming full-color images using an electrophotographic method.

[0015] With respect to the image forming apparatus 100 and its elements, the front side of the page in FIG. 1 is referred to as the "front" side, and the back side of the page in FIG. 1 is referred to as the "rear" side. Operators, such as users and service personnel, typically operate the image forming apparatus 100 from the front side of the image forming apparatus 100. The front-to-rear direction of the image forming apparatus 100 is assumed to be approximately parallel to the rotational axis direction of the photosensitive drum 1, which will be described later. With respect to the image forming apparatus 100 and its elements, the left and right sides when viewed from the front side are referred to as the "left" and "right" sides, respectively. This left-to-right direction corresponds to the width direction of the image forming apparatus 100. With respect to the image forming apparatus 100 and its elements, the "up-and-down" direction refers to the up-and-down direction in the direction of gravity (vertical direction), but does not necessarily mean directly above or directly below, and also includes the upper and lower sides of a horizontal plane passing through the element or position of interest.

[0016] The image forming apparatus 100 includes multiple image forming units, namely, first, second, third, and fourth stations SY, SM, SC, and SK, which form images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Elements in each station SY, SM, SC, and SK that have the same or corresponding functions or configurations will be generally described by omitting the Y, M, C, or K suffix to the reference numeral, indicating that the element is for one of the colors. In this embodiment, the station S includes a photosensitive drum 101, a charging device 102, an exposure device 103, a developing device 104, a primary transfer roller 105, a drum cleaning device 106, and other components, which will be described later. In this embodiment, the multiple (four in this embodiment) stations SY, SM, SC, and SK are arranged side by side in a direction intersecting the direction of gravity, particularly in a substantially horizontal direction in this embodiment.

[0017] The photosensitive drum 101, which is a rotatable drum-type photosensitive member (electrophotographic photosensitive member) serving as a first image carrier, is driven to rotate in the direction of arrow R1 in the figure. In this embodiment, four photosensitive drums 101 are arranged side by side in a substantially horizontal direction. The surface of the rotating photosensitive drum 101 is uniformly charged to a predetermined potential of a predetermined polarity (negative in this embodiment) by a charging device 102 serving as a charging means. The charged surface of the photosensitive drum 101 is scanned and exposed by an exposure device (laser scanner) 103 serving as an exposure means in accordance with image information, and an electrostatic image (electrostatic latent image) is formed on the photosensitive drum 101. The electrostatic image formed on the photosensitive drum 101 is developed (visualized) by the supply of toner by a developing device 104 serving as a developing means, and a toner image is formed on the photosensitive drum 101. In this embodiment, toner charged with the same polarity (negative in this embodiment) as the charge polarity of the photosensitive drum 101 adheres to the exposed portion (image portion) on the photosensitive drum 101, which has been uniformly charged and then exposed to light, thereby reducing the absolute value of the potential. In this embodiment, the normal charge polarity of the toner, which is the charge polarity of the toner during development, is negative.

[0018] An intermediate transfer belt 107, which is an intermediate transfer body formed of an endless belt and serves as a second image carrier, is disposed facing the four photosensitive drums 101. The intermediate transfer belt 107 is stretched around a plurality of tension rollers (support rollers), including a drive roller 171, a tension roller 172, and a secondary transfer opposing roller 173, and is tensioned with a predetermined tension. The intermediate transfer belt 107 rotates (circulates) in the direction of arrow R2 in the figure by transmitting a driving force when the drive roller 171 is driven to rotate. Primary transfer rollers 105, which are roller-type primary transfer members serving as primary transfer means, are disposed on the inner circumferential surface of the intermediate transfer belt 107 and correspond to each photosensitive drum 101. The primary transfer rollers 105 press the intermediate transfer belt 107 toward the photosensitive drums 101, forming a primary transfer portion (primary transfer nip) N1 where the photosensitive drums 101 and the intermediate transfer belt 107 come into contact. As described above, the toner images formed on the photosensitive drums 101 are primarily transferred onto the rotating intermediate transfer belt 107 at the primary transfer portion N1 by the action of the primary transfer rollers 105. During the primary transfer, a primary transfer voltage, which is a DC voltage of opposite polarity (positive polarity in this embodiment) to the normal charging polarity of the toner, is applied to the primary transfer roller 105. For example, when a full-color image is formed, the toner images of yellow, magenta, cyan, and black formed on the photosensitive drums 101 are sequentially primarily transferred onto the intermediate transfer belt 107 so as to be superimposed on top of each other.

[0019] A secondary transfer roller 108, a roller-type secondary transfer member serving as a secondary transfer means, is disposed on the outer peripheral surface of the intermediate transfer belt 107 at a position facing the secondary transfer opposing roller 173. The secondary transfer roller 108 is pressed against the secondary transfer opposing roller 173 via the intermediate transfer belt 107, forming a secondary transfer portion (secondary transfer nip) N2 where the intermediate transfer belt 107 and the secondary transfer roller 108 come into contact. The toner image formed on the intermediate transfer belt 107 as described above is secondarily transferred at the secondary transfer portion N2 onto a recording material (recording medium, sheet) P, such as recording paper, which is being conveyed while being sandwiched between the intermediate transfer belt 107 and the secondary transfer roller 108. During the secondary transfer, a secondary transfer voltage, which is a DC voltage of a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment), is applied to the secondary transfer roller 108. The recording material P is accommodated in a cassette 111, which serves as a recording material accommodation portion. The recording material P is supplied from the cassette 111 to the secondary transfer unit N2 by a recording material conveying device 112. The recording material conveying device 112 has a pickup roller 112a, a feed roller 112b, a conveying roller 112c, and a registration roller 112d. The pickup roller 112a feeds the recording material P one sheet at a time from the cassette 111. The feed roller 112b and the conveying roller 112c convey the recording material P fed out from the cassette 111. The registration roller 112d temporarily stops the recording material P conveyed by the feed roller 112b and the conveying roller 112c, and sends this recording material P to the secondary transfer unit N2 so as to synchronize with the toner image on the intermediate transfer belt 107.

[0020] The recording material P onto which the toner image has been transferred is conveyed to a fixing device 113 serving as a fixing means. The fixing device 113 has a fixing roller 113a equipped with a heat source and a pressure roller 113b that is in pressure contact with the fixing roller 113a. The fixing device 113 heats and presses the recording material P carrying the unfixed toner image by sandwiching it between the fixing roller 113a and the pressure roller 113b and conveying it, thereby fixing (melting and adhering) the toner image onto the recording material P. The recording material P onto which the toner image has been fixed is discharged (output) by a discharge roller 114 onto a tray 115 provided outside the apparatus main body 110 of the image forming apparatus 100.

[0021] Furthermore, toner that remains on the photosensitive drum 101 without being transferred to the intermediate transfer belt 107 during the primary transfer (primary transfer residual toner) is removed from the photosensitive drum 101 and collected by a drum cleaning device 106 serving as a photosensitive body cleaning means. As shown in FIG. 2, the drum cleaning device 106 has a drum cleaning blade 161 formed of an elastic body as a cleaning member, and a drum cleaning container 162 as a toner collection unit. The drum cleaning device 106 scrapes the primary transfer residual toner from the surface of the rotating photosensitive drum 101 by the drum cleaning blade 161 arranged to abut against the surface of the photosensitive drum 101, and stores it inside the drum cleaning container 162.

[0022] Furthermore, a belt cleaning device 109 serving as an intermediate transfer belt cleaning means is disposed on the outer peripheral surface side of the intermediate transfer belt 107, at a position facing the tension roller 172. Toner that remains on the intermediate transfer belt 107 without being transferred to the recording material P during the secondary transfer (secondary transfer residual toner) is removed from the intermediate transfer belt 107 and collected by the belt cleaning device 109. As shown in FIG. 2, the belt cleaning device 109 has a belt cleaning blade 191 formed of an elastic body as a cleaning member, and a belt cleaning container 192 as a toner collection unit. The belt cleaning device 109 scrapes secondary transfer residual toner from the surface of the rotating intermediate transfer belt 107 by the belt cleaning blade 191 disposed so as to abut against the surface of the intermediate transfer belt 107, and collects the scraped toner inside the belt cleaning container 192.

[0023] The primary transfer residual toner contained in the drum cleaning container 162 is transported by a transport means (not shown) arranged inside the drum cleaning container 162. Then, this primary transfer residual toner is discharged from a drum cleaning container outlet 162a, which is an opening, and sent to a developer recovery device 1, which will be described later, as a recovered developer. Meanwhile, the secondary transfer residual toner contained in the belt cleaning container 192 is transported by a transport means (not shown) arranged inside the belt cleaning container 192. Then, this secondary transfer residual toner is discharged from a belt cleaning container outlet 192a, which is an opening, and sent to a developer recovery device 1, which will be described later, as a recovered developer.

[0024] In this embodiment, at each station S, the photosensitive drum 101 and the charging device 102, developing device 104, and drum cleaning device 106, which act as process means, integrally form a process cartridge 117. The process cartridge 117 is configured so that it can be pulled out to the front of the image forming apparatus 100 and detached from the apparatus main body 110. The process cartridges 117 for each color have substantially the same structure, except that the color of toner contained in the developing device 104 is different.

[0025] In this embodiment, the intermediate transfer belt 107, tension rollers 171 to 173 for the intermediate transfer belt 107, the primary transfer rollers 105, and the belt cleaning device 109 are integrated into a unit to form an intermediate transfer unit 170. The intermediate transfer unit 170 is configured so as to be detachable from the apparatus main body 110 by being pulled out from the right side of the image forming apparatus 100.

[0026] The image forming apparatus 100 is also provided with toner cartridges 116Y, 116M, 116C, and 116K as replenishment developer containers that contain developer (replenishment developer) to be replenished to the developing devices 104Y, 104M, 104C, and 104K. The toner cartridges 116 are configured to be removable from the apparatus main body 110 by being pulled out toward the front of the image forming apparatus 100. The toner cartridges 116 for each color have substantially the same structure except for the color of toner they contain. The toner cartridges 116 have a replenishment developer container 116a that contains the replenishment developer, and a replenishment screw 116b that is a replenishment member that serves as a replenishment means for replenishing the replenishment developer in the replenishment developer container 116a to the developing devices 104.

[0027] In this embodiment, the developing device 104 uses a two-component developer containing toner (non-magnetic toner particles) and carrier (magnetic carrier particles) as the developer. As shown in FIG. 2, the developing device 104 has a rotatable developing sleeve 141 as a developer carrier and a developing container 142 that contains the developer. The developing device 104 carries the developer containing toner and carrier on the developing sleeve 141, and transports the developer to a developing position where the photosensitive drum 101 and the developing sleeve 141 face each other by the rotation of the developing sleeve 141. The developing device 104 supplies the toner of the developer to the electrostatic image on the photosensitive drum 101 at the developing position, thereby forming a toner image on the photosensitive drum 101. In addition, a stirring and transporting unit (not shown) arranged inside the developing container 142 stirs and circulates the developer contained in the developing container 142 and the replenished developer replenished from the toner cartridge 116. In this embodiment, the replenishment developer replenished from the toner cartridge 116 to the developing device 104 contains toner and carrier. Then, the developer (which may contain toner and carrier) inside the developing container 142 that has become excessive due to the replenishment of the replenishment developer is discharged from a developing container outlet 142a, which is an opening, as the developer is circulated and transported inside the developing container 142, and is sent to the developer recovery device 1, which will be described later, as recovered developer.

[0028] In this embodiment, each station S, the intermediate transfer unit 170, the secondary transfer roller 108, and the fixing device 113 constitute an image forming section G, which is a mechanism for forming an image on a recording material P using a developer. Note that Fig. 2 is a schematic diagram showing the manner in which recovered developer is discharged from the image forming section G (the drum cleaning device 106 and the developing device 104 of each station S, and the belt cleaning device 109).

[0029] 2. Developer recovery container In this embodiment, the apparatus main body 110 of the image forming apparatus 100 is provided with a plurality of recovered developer containers (recovery containers , storage container The two containers, first and second recovered developer containers 10L and 10R, are detachably attached. In this embodiment, the first and second recovered developer containers 10L and 10R are arranged side by side in a substantially horizontal direction inside the apparatus main body 110. In particular, in this embodiment, the first and second recovered developer containers 10L and 10R have substantially the same structure and are arranged side by side at substantially the same height in the vertical direction inside the apparatus main body 110. The recovered developer sent from the image forming unit G to the developer recovery device 1 (described later) is selectively transported to and accumulated in either one of the first and second recovered developer containers 10L and 10R. In this embodiment, as described above, the recovered developer (waste toner) is discharged from the drum cleaning device 106, the developing device 104, and the belt cleaning device 109 of each station S in the image forming unit G. Furthermore, when the inside of either the first or second recovered developer container 10L, 10R becomes full with recovered developer, the destination of the recovered developer is switched to the other container, and the one container is replaced with an empty container.

[0030] In addition, when the first and second recovered developer containers 10L and 10R are arranged side by side in an approximately horizontal direction, this also includes arranging the first and second recovered developer containers 10L and 10R so that they overlap at least partially in the vertical direction.

[0031] The first and second recovered developer containers 10L and 10R are box-shaped containers each having a predetermined length in the longitudinal direction and a predetermined thickness (height) in the thickness direction, and having a substantially rectangular cross section substantially perpendicular to the longitudinal direction. The longitudinal direction is the direction in which the containers are disposed along the front-to-rear direction of the image forming apparatus 100 inside the apparatus main body 110. The lateral direction is the direction in which the containers are disposed along the left-to-right direction of the image forming apparatus 100 inside the apparatus main body 110. The thickness direction is the direction in which the containers are disposed along the up-to-down direction inside the apparatus main body 110. The first and second recovered developer containers 10L and 10R each have hollow recovered developer storage portions 11L and 11R (see FIGS. 6 and 7) for storing recovered developer therein. As described above, in this embodiment, the first and second recovered developer containers 10L and 10R have substantially the same structure, and each container can be mounted on either the left or right side inside the apparatus main body 110. In this embodiment, the first recovered developer container (first recovered container) 10L is mounted on the left side inside the device main body 110, and the second recovered developer container (second recovered container) 10R is mounted on the right side inside the device main body 110.

[0032] FIG. 3 is a schematic perspective view of the image forming apparatus 100, seen obliquely from the front, illustrating the manner in which the first and second collected developer containers 10L and 10R are attached. FIG. 3(a) shows a state in which a container replacement door 118 (described later) is closed, and FIG. 3(b) shows a state in which the container replacement door 118 is open, allowing the first and second collected developer containers 10L and 10R to be attached and detached. The container replacement door 118, which constitutes part of the exterior cover of the image forming apparatus 100 and allows the first and second collected developer containers 10L and 10R to be attached and detached, is provided on the front side of the image forming apparatus 100. In this embodiment, the container replacement door 118 is configured as a single (common) opening / closing member that allows both the first and second collected developer containers 10L and 10R to be attached and detached. In this embodiment, the container replacement door 118 has a generally rectangular shape that is elongated in the left-right direction when viewed from the front. In this embodiment, the container replacement door 118 is configured to be rotatable about a rotation axis extending in the left-right direction (width direction) that intersects with the up-down direction at the bottom of the door. The container replacement door 118 can be opened and closed by rotating the upper part around the rotation axis extending in the left-right direction at the lower part in the up-down direction, by the operator's operation.

[0033] As shown in FIG. 3A, when the container replacement door 118 is closed, it has the appearance of a single panel whose size in the left-right and up-down directions is equal to that of the front panel 111a of the cassette 111 provided adjacently below it. This prevents the appearance from becoming cluttered due to the provision of two containers, the first and second collected developer containers 10L and 10R. Furthermore, by opening and closing the single container replacement door 118, both the first and second collected developer containers 10L and 10R can be attached and detached. This prevents unnecessary operations caused by an operator opening and closing the wrong door, which can occur when separate container replacement doors are provided for multiple collected developer containers.

[0034] As shown in FIG. 3(b), by opening the container replacement door 118, an operator can access both the first and second collected developer containers 10L and 10R. The apparatus main body 110 is provided with first and second container mounting portions 119L and 119R, to which the first and second collected developer containers 10L and 10R are respectively mounted. The first and second container mounting portions 119L and 119R have first and second container support portions 120L and 120R extending in the front-to-rear direction and supporting the undersides of the first and second collected developer containers 10L and 10R, respectively. The first and second container mounting portions 119L and 119R have, for example, rail-like structures (not shown) that allow the first and second container support portions 120L and 120R to engage with the first and second collected developer containers 10L and 10R, respectively. This allows the first and second collected developer containers 10L, 10R to be slid from the front side to the rear side and easily placed at predetermined positions inside the device main body 110. This also allows the first and second collected developer containers 10L, 10R to be slid from the rear side to the front side and easily removed from the device main body 110 by pulling them out from their predetermined positions inside the device main body 110.

[0035] 3(b), identification marks (identification marking portions) 121L and 121R are provided on the inner surface of the container replacement door 118 so that the operator can see them when the container replacement door 118 is open. The identification marks 121L and 121R are provided at positions corresponding to the first and second collected developer containers 10L and 10R in the left-right direction. In this embodiment, the identification marks 121L and 121R are provided on the inner surface of the container replacement door 118 at positions adjacent to the first and second container mounting portions 119L and 119R in front of the respective mounting portions, in an area that at least partially overlaps the respective mounting portions in the left-right direction. In this embodiment, the first identification mark (first mark) 121L on the left side is configured as a sticker on which characters such as "CONTAINER 1" (or "LEFT CONTAINER") are written as first identification information for identifying the first collected developer container 10L. In this embodiment, the second identification mark (second mark) 121R on the right side is configured as a sticker with characters such as "CONTAINER 2" (or "RIGHT CONTAINER") written on it as second identification information for identifying the second collected developer container 10R. These identification marks 121L, 121R are intended to make it easy to identify the corresponding container when a display prompting replacement of either collected developer container 10L, 10R is displayed on the operation unit 130 (FIG. 11) of the image forming apparatus 100, as will be described later. While the identification marks 121L, 121R are provided on the inner surface of the container replacement door 118 in this embodiment, this is not limiting. The identification marks 121L, 121R may be provided, for example, on the front surfaces of panels adjacent to the first and second container mounting portions 119L, 119R, respectively, corresponding to the first and second collected developer containers 10L, 10R.

[0036] 3. Structure of the developer recovery device Next, the configuration of the developer recovery device (conveyance device) 1 in this embodiment will be described.

[0037] <Overall structure> Fig. 4 is a front view of the developer recovery device 1 of this embodiment as seen from the front. Fig. 5 is a perspective view of the developer recovery device 1 of this embodiment as seen from the diagonally front. Figs. 4 and 5 mainly show the recovered developer transport path 2 in the developer recovery device 1, and also show the first and second recovered developer containers 10L and 10R connected to the developer recovery device 1.

[0038] In this embodiment, the recovered developer transport path 2 of the developer recovery device 1 roughly includes an upstream transport section 3 and a downstream transport section 4. The upstream transport section 3 receives the recovered developer discharged from the image forming section G (the drum cleaning device 106 and the developing device 104 of each station S, and the belt cleaning device 109). The downstream transport section 4 receives the recovered developer from the upstream transport section 3 and transports it to the first and second recovered developer containers 10L and 10R.

[0039] <Upstream conveying section> 4 and 5, the upstream conveying section 3 has first to fifth discharge pipes 31 to 35 and a main discharge pipe 36. The first to fifth discharge pipes 31 to 35 and the main discharge pipe 36 are disposed near the rear end of the inside of the apparatus body 110.

[0040] In this embodiment, the first to fifth discharge pipes 31 to 35 are hollow tubular members that extend vertically substantially in the direction of gravity. The first discharge pipe 31 is formed with a first discharge receiving port 31a, which is an opening connected to the belt cleaning container discharge outlet 192a (FIG. 2), and a second discharge receiving port 31b, which is an opening connected to the yellow developer container discharge outlet 142a (FIG. 2). The second discharge pipe 32 is formed with a first discharge receiving port 32a, which is an opening connected to the yellow drum cleaning container discharge outlet 162a (FIG. 2), and a second discharge receiving port 32b, which is an opening connected to the magenta developer container discharge outlet 142a (FIG. 2). The third discharge pipe 33 is formed with a first discharge receiving port 33a connected to the magenta drum cleaning container discharge outlet 162a (FIG. 2) and a second discharge receiving port 33b, which is an opening connected to the cyan developer container discharge outlet 142a (FIG. 2). The fourth discharge pipe 34 is formed with a first discharge receiving port 34a connected to the cyan drum cleaning container discharge outlet 162a (FIG. 2) and a second discharge receiving port 34b, which is an opening connected to the black developer container discharge outlet 142a (FIG. 2). The fifth discharge pipe 35 is formed with a discharge receiving port 35a connected to the black drum cleaning container discharge outlet 162a (FIG. 2). The lower ends of the first to fifth discharge pipes 31 to 35 are connected to the main discharge pipe 36, and the insides of the first to fifth discharge pipes 31 to 35 and the inside of the main discharge pipe 36 are connected to each other so that the recovered developer can be transferred between them.

[0041] In this embodiment, the main discharge pipe 36 serving as the discharge conveyance section (discharge conveyance path) is a hollow tubular member extending laterally in a substantially horizontal direction. In particular, in this embodiment, the main discharge pipe 36 is configured as a circular pipe with a substantially circular cross section substantially perpendicular to its extension direction (axial direction, extension direction). The first to fifth discharge pipes 31 to 35 are connected to the upper side portions of the main discharge pipe 36, respectively, and the interiors of the main discharge pipe 36 and the first to fifth discharge pipes 31 to 35 are connected to each other so that the recovered developer can be transferred. A discharge screw 37 serving as a discharge conveyance member is disposed inside (hollow portion of) the main discharge pipe 36. In this embodiment, the discharge screw 37 is configured as a shaftless screw conveyor (spring auger) rotatable about a rotation axis extending laterally along the extension direction (substantially horizontal direction) of the main discharge pipe 36. The discharge screw 37 conveys the recovered developer inside the main discharge pipe 36 while stirring it. A main discharge port (discharge transport path discharge port) 36a is formed in a lower side portion of the main discharge pipe 36 located between both end portions in the extension direction of the main discharge pipe 36. This main discharge port 36a is an opening for allowing the recovered developer to fall by gravity from the main discharge pipe 36 and be discharged to the downstream transport section 4. In this embodiment, the main discharge port 36a is formed in the following position in the horizontal direction in a cross section substantially perpendicular to the front-rear direction of the image forming apparatus 100. That is, the main discharge port 36a is formed in the lower side portion of the main discharge pipe 36 so as to be located between first and second horizontal pipe discharge ports 42b and 42c provided in a horizontal pipe 42 of the downstream transport section 4, which will be described later, in this direction.

[0042] The recovered developer sent to the first to fifth discharge pipes 31 to 35 falls by gravity through the interiors (hollow portions) of the first to fifth discharge pipes 31 to 35 and moves to the main discharge pipe 36. The recovered developer that falls into the main discharge pipe 36 is transported to the main discharge port 36a by the discharge screw 37. In this embodiment, the discharge screw 37 has a spiral shape in which the winding directions of a first portion 37a on the left side and a second portion 37b on the right side are different with respect to the rotational axis direction of the discharge screw 37, with the position corresponding to the main discharge port 36a as the boundary. In addition, the discharge screw 37 is rotationally driven in a predetermined direction by a rotational driving force transmitted from a discharge drive motor (not shown) serving as a drive source for a discharge drive unit 126 (FIG. 11) via a drive transmission member (such as one or more gears) 125. The discharge drive unit 126 is provided in the device main body 110. As a result, the recovered developer sent from the first and second discharge pipes 31 and 32 to the main discharge pipe 36 is transported from the left to the right by the first portion 37a of the discharge screw 37 and sent to the main discharge port 36a. On the other hand, the recovered developer sent from the third to fifth discharge pipes 33 to 35 to the main discharge pipe 36 is transported from the right to the left by the second portion 37b of the discharge screw 37 and sent to the main discharge port 36a. The recovered developer transported to the main discharge port 36a falls from the main discharge port 36a by gravity and moves to a vertical pipe 41 of the downstream transport unit 4, which will be described later.

[0043] <Downstream conveying section> 4 and 5, the downstream conveying section 4 has a vertical pipe 41, a horizontal pipe 42, and first and second recovery pipes 44L, 44R. The vertical pipe 41 and the horizontal pipe 42 are disposed near the rear end inside the apparatus main body 110. The first and second recovery pipes 44L, 44R are disposed above the first and second recovered developer containers 10L, 10R disposed inside the apparatus main body 110, extending from the rear side to the front side.

[0044] The developer recovery device 1 has a vertical pipe 41 as a tubular vertical transport section (vertical transport path) that guides recovered developer discharged from the image forming section G from above to below in the direction of gravity. In this embodiment, the vertical pipe 41 is a hollow tubular member that extends vertically approximately in the direction of gravity. Note that the vertical pipe 41 may be inclined with respect to the direction of gravity. In this embodiment, the recovered developer falls within the vertical pipe 41 due to gravity, but a transport member for transporting the recovered developer may be provided within the vertical pipe 41. The main discharge pipe 36 of the upstream transport section 3 is connected to the upper end of the vertical pipe 41. A vertical pipe receiving port 41a, which is an opening for receiving recovered developer discharged from the main discharge port 36a into the vertical pipe 41, is formed at the upper end of the vertical pipe 41 at a position corresponding to the main discharge port 36a of the main discharge pipe 36. This allows the interior of the main discharge pipe 36 to communicate with the interior of the vertical pipe 41 via the main discharge port 36a and the vertical pipe receiving port 41a. Furthermore, a vertical pipe discharge port 41b, which is an opening for allowing the recovered developer to fall by gravity from the vertical pipe 41 and be delivered to the horizontal pipe 42, is formed at the lower end of the vertical pipe 41. In this embodiment, the vertical pipe inlet 41a and the vertical pipe discharge port 41b are formed at the following positions in the horizontal direction in a cross section that is approximately perpendicular to the front-to-rear direction of the image forming apparatus 100. That is, the vertical pipe inlet 41a and the vertical pipe discharge port 41b are formed on the vertical pipe 41 so as to be located between first and second horizontal pipe discharge ports 42b and 42c provided on the horizontal pipe 42, which will be described later, in the horizontal direction.

[0045] The developer recovery device 1 has a horizontal pipe 42 as a tubular horizontal conveying section (horizontal conveying path). The horizontal pipe 42 can guide the recovered developer conveyed through the vertical pipe 41 toward the first recovered developer container 10L and the second recovered developer container 10R in a direction intersecting the direction of gravity. In this embodiment, the horizontal pipe 42 is a hollow tubular member extending laterally along a substantially horizontal direction. The horizontal pipe 42 may be inclined with respect to the horizontal direction. Particularly in this embodiment, the horizontal pipe 42 is configured as a circular pipe with a substantially circular cross section substantially perpendicular to its extension direction (axial direction, extension direction). The vertical pipe 41 is connected to the upper side of the horizontal pipe 42 between both ends in the extension direction of the horizontal pipe 42. A horizontal pipe receiving port 42a, which is an opening for receiving the recovered developer discharged from the vertical pipe discharge port 41b into the horizontal pipe 42, is formed in the upper side of the horizontal pipe 42 at a position corresponding to the vertical pipe discharge port 41b of the vertical pipe 41. As a result, the interior of the vertical pipe 41 communicates with the interior of the horizontal pipe 42 via the vertical pipe discharge port 41b and the horizontal pipe receiving port 42a. Also, first and second horizontal pipe discharge ports 42b and 42c are formed on the lower side portions of the horizontal pipe 42 located on both end sides in the extension direction of the horizontal pipe 42, respectively. The first and second horizontal pipe discharge ports 42b and 42c are openings that allow the recovered developer to fall by gravity from the horizontal pipe 42 and be discharged to the first and second recovery pipes 44L and 44R, respectively. The first horizontal pipe discharge port 42b is formed near one end (first end) of the horizontal pipe 42, and the second horizontal pipe discharge port 42c is formed near the other end (second end) of the horizontal pipe 42, which is the right end (second end) of the horizontal pipe 42. Here, the horizontal pipe receiving port 42a is formed in the horizontal pipe 42 so as to be located between the first and second horizontal pipe discharge ports 42b, 42c in the horizontal direction in a cross section substantially perpendicular to the front-rear direction of the image forming apparatus 100. In this way, the horizontal pipe 42 has the first horizontal pipe discharge port 42b, which is provided on the first end side in the extension direction of the horizontal pipe 42 and discharges the recovered developer from the horizontal pipe 42 toward the first recovered developer container 10L.The horizontal pipe 42 also has a second horizontal pipe discharge port 42c, which is provided at a second end opposite to the first end in the extension direction of the horizontal pipe 42, and which discharges the recovered developer from the horizontal pipe 42 toward the second recovered developer container 10R. The horizontal pipe 42 also has a horizontal pipe receiving port 42a, which is provided between the first horizontal pipe discharge port 42b and the second horizontal pipe discharge port 42c in the extension direction of the horizontal pipe 42, and which receives the recovered developer from the vertical pipe 41 into the horizontal pipe 42.

[0046] A conveying screw 43 serving as a conveying member is disposed inside (in the hollow portion of) the horizontal pipe 42. In this embodiment, the conveying screw 43 is configured as a shaftless screw conveyor (spring auger) that can rotate about a rotation axis extending laterally along the extension direction (substantially horizontal direction) of the horizontal pipe 42. In this embodiment, the conveying screw 43 has a spiral shape that winds in one direction. The conveying screw 43 conveys the recovered developer inside the horizontal pipe 42 while stirring it. The conveying screw 43 is driven to rotate by a rotational driving force transmitted from the drive unit 5. In this embodiment, the drive unit 5 includes a drive motor 51 as a driving source and a drive train (e.g., one or more gears) 52 that transmits the driving force from the drive motor 51 to the conveying screw 43. In this embodiment, the drive motor 51 is disposed on the right side of the horizontal pipe 42, and the drive train 52 is connected to the right end of the conveying screw 43. The drive motor 51 of the drive unit 5 is rotatable in both forward and reverse directions. As a result, the drive unit 5 can drive the conveying screw 43 to rotate in a first direction and a second direction opposite to the first direction. As described above, the conveying screw 43 has a spiral shape with a winding direction in one direction, and by rotating in the first direction, it conveys the recovered developer inside the horizontal pipe 42 from the right end (second end) side toward the left end (first end) side. Furthermore, by rotating in the second direction, the conveying screw 43 conveys the recovered developer inside the horizontal pipe 42 from the left end (first end) side toward the right end (second end) side. In this way, the developer recovery device 1 has the conveying screw 43 that conveys the recovered developer inside the horizontal pipe 42. The conveying screw 43 has a spiral-shaped portion with a winding direction that conveys the recovered developer as follows. That is, the conveying screw 43 conveys the recovered developer in a direction from the second end toward the first end along the rotation axis by rotating in a first direction around a rotation axis that is aligned with the extension direction of the horizontal pipe 42. Furthermore, the conveying screw 43 conveys the recovered developer in a direction from the first end toward the second end along the rotation axis by rotating in a second direction opposite to the first direction around the rotation axis.The developer recovery device 1 also has a drive unit 5 that can drive the conveying screw 43 to rotate in a first direction and a second direction.

[0047] The developer recovery device 1 has a first recovery pipe 44L as a tubular first recovery conveying section (first recovery conveying path) that guides the recovered developer discharged from the first horizontal pipe discharge port 42b toward the first recovered developer container 10L. In this embodiment, the first recovery pipe 44L is a hollow tubular member extending back and forth along a substantially horizontal direction. The first recovery pipe 44L may be inclined with respect to the horizontal direction. Particularly in this embodiment, the first recovery pipe 44L is configured as a circular pipe with a substantially circular cross section substantially perpendicular to its extension direction (axial direction, extension direction). The horizontal pipe 42 is connected to an upper side portion of the first recovery pipe 44L located at the rear end in the extension direction of the first recovery pipe 44L. A first recovery receiving port 44aL is formed on the upper side portion of the first recovery pipe 44L at a position corresponding to the first horizontal pipe discharge port 42b of the horizontal pipe 42. The first recovery receiving port 44aL is an opening for receiving the recovered developer discharged from the first horizontal pipe discharge port 42b into the first recovery pipe 44L. As a result, the interior of the horizontal pipe 42 is connected to the interior of the first recovery pipe 44L via the first horizontal pipe discharge port 42b and the first recovery receiving port 44aL. In addition, a first recovery discharging port 44bL is formed in a lower side portion of the first recovery pipe 44L located at the front end in the extension direction of the first recovery pipe 44L. The first recovery discharging port 44bL is an opening for allowing the recovered developer to fall by gravity from the first recovery pipe 44L and be discharged into the first recovered developer container 10L. In this way, the first recovery pipe 44L is provided with a first recovery receiving port 44aL, which is provided at one end side in the extension direction of the first recovery pipe 44L and receives the recovered developer discharged from the first horizontal pipe discharge port 42b into the first recovery pipe 44L. Also, the first recovery pipe 44L is provided with a first recovery discharging port 44bL, which is provided at the other end side in the extension direction of the first recovery pipe 44L and discharges the recovered developer from the first recovery pipe 44L toward the first recovered developer container 10L.

[0048] A first recovery screw 45L serving as a first recovery and transport member is disposed inside (in a hollow portion of) the first recovery pipe 44L. In this embodiment, the first recovery screw 45L is configured as a shaftless screw conveyor (spring auger) that can rotate around a rotation axis extending back and forth along the extension direction (substantially horizontal direction) of the first recovery pipe 44L. In this embodiment, the first recovery screw 45L has a spiral shape with a unidirectional winding direction. The first recovery screw 45L transports the recovered developer inside the first recovery pipe 44L while stirring it. Figure 7 is a cross-sectional view taken along line YY in Figure 4. As shown in Figure 7, the first recovery screw 45L is rotationally driven by a rotational driving force transmitted from the first recovery drive unit 6L. In this embodiment, the first collection drive unit 6L includes a first collection drive motor 61L as a drive source and a first collection drive train (e.g., one or more gears) 62L that transmits the drive force from the first collection drive motor 61L to the first collection screw 45L. In this embodiment, the first collection drive motor 61L is disposed below and near the rear end of the first collection pipe 44L, and the first collection drive train 62L is connected to the rear end of the first collection screw 45L. The first collection drive motor 61L of the first collection drive unit 6L rotates in a predetermined direction. This causes the first collection drive unit 6L to rotate the first collection screw 45L in the predetermined direction. As described above, the first collection screw 45L has a spiral shape that winds in one direction. By rotating in the predetermined direction, the collected developer inside the first collection pipe 44L is transported from the rear end to the front end. As described above, the developer recovery device 1 has a first recovery screw 45L that transports the recovered developer inside the first recovery pipe 44L. The first recovery screw 45L has a spiral-shaped portion in a winding direction that transports the recovered developer as follows. That is, the first recovery screw 45L rotates in a predetermined direction about a rotation axis that is along the extension direction of the first recovery pipe 44L. By rotating in this manner, the first recovery screw 45L transports the recovered developer along the rotation axis in a direction from one end side (rear end side) of the first recovery pipe 44L to the other end side (front end side).In this embodiment, the developer recovery device 1 also has a first recovery drive portion 6L that rotationally drives the first recovery screw 45L.

[0049] Furthermore, the developer recovery device 1 has a second recovery pipe 44R as a tubular second recovery conveying section (second recovery conveying path) that guides the recovered developer discharged from the second horizontal pipe discharge port 42c toward the second recovered developer container 10R. In this embodiment, the second recovery pipe 44R is a hollow tubular member extending back and forth along a substantially horizontal direction. The second recovery pipe 44R may be inclined with respect to the horizontal direction. Particularly in this embodiment, the second recovery pipe 44R is configured as a circular pipe with a substantially circular cross section substantially perpendicular to its extension direction (axial direction, extension direction). The horizontal pipe 42 is connected to the upper side portion of the second recovery pipe 44R, which is located at the rear end in the extension direction of the second recovery pipe 44R. A second recovery receiving port 44aR is formed on the upper side portion of the second recovery pipe 44R at a position corresponding to the second horizontal pipe discharge port 42c of the horizontal pipe 42. The second recovery receiving port 44aR is an opening for receiving the recovered developer discharged from the second horizontal pipe discharge port 42c into the second recovery pipe 44R. As a result, the interior of the horizontal pipe 42 communicates with the interior of the second recovery pipe 44R via the second horizontal pipe discharge port 42c and the second recovery receiving port 44aR. In addition, a second recovery discharging port 44bR is formed on the lower side of the second recovery pipe 44R, which is located at the front end in the extension direction of the second recovery pipe 44R. The second recovery discharging port 44bR is an opening for allowing the recovered developer to fall by gravity from the second recovery pipe 44R and be discharged into the second recovered developer container 10R. In this way, the second recovery pipe 44R is provided with a second recovery receiving port 44aR, which is provided at one end side in the extension direction of the second recovery pipe 44R and receives the recovered developer discharged from the second horizontal pipe discharge port 42c into the second recovery pipe 44R. Also, the second recovery pipe 44R is provided with a second recovery discharging port 44bR, which is provided at the other end side in the extension direction of the second recovery pipe 44R and discharges the recovered developer from the second recovery pipe 44R toward the second recovered developer container 10R.

[0050] A second recovery screw 45R serving as a second recovery and transport member is disposed inside (in the hollow portion of) the second recovery pipe 44R. In this embodiment, the second recovery screw 45R is configured as a shaftless screw conveyor (spring auger) that can rotate around a rotation axis extending back and forth along the extension direction (substantially horizontal direction) of the second recovery pipe 44R. In this embodiment, the second recovery screw 45R has a spiral shape with a unidirectional winding direction. The second recovery screw 45R transports the recovered developer inside the second recovery pipe 44R while stirring it. Figure 6 is a cross-sectional view taken along line XX in Figure 4. As shown in Figure 6, the second recovery screw 45R is rotationally driven by a rotational driving force transmitted from the second recovery drive unit 6R. In this embodiment, the second collection drive unit 6R includes a second collection drive motor 61R as a drive source and a second collection drive train (e.g., one or more gears) 62R that transmits the drive force from the second collection drive motor 61R to the second collection screw 45R. In this embodiment, the second collection drive motor 61R is disposed below and near the rear end of the second collection pipe 44R, and the second collection drive train 62R is connected to the rear end of the second collection screw 45R. The second collection drive motor 61R of the second collection drive unit 6R rotates in a predetermined direction. This causes the second collection drive unit 6R to rotate the second collection screw 45R in the predetermined direction. As described above, the second collection screw 45R has a spiral shape that winds in one direction. By rotating in the predetermined direction, the second collection screw 45R transports the collected developer inside the second collection pipe 44R from the rear end to the front end. As described above, the developer recovery device 1 has a second recovery screw 45R that transports the recovered developer inside the second recovery pipe 44R. The second recovery screw 45R has a spiral-shaped portion in a winding direction that transports the recovered developer as follows. That is, the second recovery screw 45R rotates in a predetermined direction about a rotation axis that is along the extension direction of the second recovery pipe 44R. By rotating in this manner, the second recovery screw 45R transports the recovered developer along the rotation axis from one end side (rear end side) of the second recovery pipe 44R to the other end side (front end side).In addition, in this embodiment, the developer recovery device 1 has a second recovery drive portion 6R that rotationally drives the second recovery screw 45R.

[0051] As described above, in this embodiment, the downstream conveying section 4 has a first downstream conveying section (horizontal pipe 42, conveying screw 43) that can receive the recovered developer discharged from the upstream conveying section 3 and convey it toward the first recovered developer container 10L and the second recovered developer container 10R. Also, in this embodiment, the downstream conveying section 4 has a second downstream conveying section (first recovery pipe 44L, first recovery screw 45L) that conveys the recovered developer passed from the first downstream conveying section to the first recovered developer container 10L. Also, in this embodiment, the downstream conveying section 4 has a third downstream conveying section (second recovery pipe 44R, second recovery screw 45R) that conveys the recovered developer passed from the first downstream conveying section to the second recovered developer container 10R.

[0052] It is also possible that the first and second recovery pipes 44L and 44R are not provided, and the recovered developer is sent directly from the horizontal pipe 42 to the first and second recovered developer containers 10L and 10R, for example.

[0053] In this embodiment, the first and second recovered developer containers 10L and 10R have first and second container receiving openings 12L and 12R, respectively, on their upper side portions located at the front end when the first and second recovered developer containers 10L and 10R are disposed at predetermined positions within the apparatus main body 110. The first and second container receiving openings 12L and 12R are openings for receiving recovered developer discharged from the first and second recovery and discharge openings 44bL and 44bR into the first and second recovered developer containers 10L and 10R, respectively. When the first and second recovered developer containers 10L and 10R are attached to predetermined positions within the apparatus main body 110, the first and second container receiving openings 12L and 12R are positioned corresponding to the first and second recovery and discharge openings 44bL and 44bR, respectively. This allows communication between the interiors of the first and second recovery pipes 44L and 44R and the interiors of the first and second recovered developer containers 10L and 10R. In this embodiment, first and second shutter members 46L and 46R are provided at the front ends of the first and second recovery pipes 44L and 44R, respectively, to switch the open and closed states of the first and second recovery and discharge ports 44bL and 44bR. The first and second shutter members 46L and 46R are provided on the first and second recovery pipes 44L and 44R so as to be slidable in the front-to-rear direction, and are biased in the rear-to-front direction by a shutter pressure spring (not shown) serving as a biasing means. Then, just before the first and second recovered developer containers 10L and 10R are installed in predetermined positions within the apparatus main body 110, engaging portions (not shown) provided on the first and second recovered developer containers 10L and 10R engage with the first and second shutter members 46L and 46R. Then, when the first and second collected developer containers 10L, 10R are further inserted to predetermined positions inside the apparatus main body 110, the first and second shutter members 46L, 46R are moved rearward against the biasing force of the shutter pressing spring and are opened. That is, at this time, the first and second shutter members 46L, 46R are disposed at open positions that open the first and second collected and discharge ports 44bL, 44bR, respectively. When the first and second collected developer containers 10L, 10R are removed from their predetermined positions inside the apparatus main body 110, the first and second shutter members 46L, 46R are closed by the biasing force of the shutter pressing spring in the reverse order of the above-described operations.That is, at this time, the first and second shutter members 46L, 46R are disposed at the closed position where they close the first and second recovery and discharge openings 44bL, 44bR, respectively. Note that the shutter members are not limited to those that open and close in conjunction with the movement of the recovered developer container, and may be those that open and close by, for example, an appropriate actuator. Furthermore, the first and second recovered developer containers 10L, 10R may also be provided with shutter members that open and close the first and second container receiving openings 12L, 12R in conjunction with, for example, the above-mentioned mounting and removal operations.

[0054] In this embodiment, as shown in FIGS. 6 and 7, first and second container screws 13L and 13R are provided inside the first and second recovered developer containers 10L and 10R as container transport members for transporting the recovered developer contained in the recovered developer storage compartments 11L and 11R. In this embodiment, the first and second container screws 13L and 13R are configured to transport the recovered developer from the front to the rear when the first and second recovered developer containers 10L and 10R are disposed at predetermined positions inside the apparatus main body 110. In this embodiment, the first and second container screws 13L and 13R have a rotation shaft and a screw blade formed in a spiral shape around the rotation shaft. In addition, a drive receiver is provided at the rear end of the rotation shaft of each of the first and second container screws 13L and 13R. When the first and second recovered developer containers 10L and 10R are installed at predetermined positions inside the apparatus main body 110, the drive receiving portions are connected to the first and second couplings 63L and 63R provided on the apparatus main body 110, respectively. In this embodiment, the first and second couplings 63L and 63R are rotated by the rotational drive force transmitted from the first and second recovery drive portions 6L and 6R described above. As a result, in this embodiment, the first and second container screws 13L and 13R rotate in conjunction with the first and second recovery screws 45L and 45R, respectively, to transport the recovered developer inside the first and second recovered developer containers 10L and 10R. As shown in FIG. 8, the first and second couplings 63L and 63R are provided so as to be exposed from the first and second container facing portions 122L and 122R, respectively, which will be described later.

[0055] As described above, in this embodiment, the image forming apparatus 100 has the developer recovery device 1 as a transport device that can selectively transport recovered developer discharged from the image forming unit G to the first recovered developer container 10L or the second recovered developer container 10R. In this embodiment, the developer recovery device 1 as a transport device is configured to include a main discharge pipe 36, a discharge screw 37, a vertical conveying pipe 41, a horizontal conveying pipe 42, a conveying screw 43, first and second recovery pipes 44L and 44R, first and second recovery screws 45L and 45R, a discharge drive unit 126, a drive unit 5, first and second recovery drive units 6L and 6R, etc.

[0056] <Container sensors, etc.> Figure 8 shows the first and second container opposing portions 122L, 122R that face the first and second recovered developer containers 10L, 10R at the rear ends of the first and second container mounting portions 119L, 119R (Figure 3(b)) of the device main body 110.

[0057] In this embodiment, the first and second container facing portions 122L and 122R are provided with container detection means for detecting the presence or absence (attachment / detachment state) of the first and second recovered developer containers 10L and 10R, respectively. (Wearing detection unit)First and second container sensors 7L and 7R are provided as sensors for detecting the developer container 10L. In this embodiment, the first and second container sensors 7L and 7R are configured as mechanical switches that change the signal output to a control unit 150 (FIG. 11) described later depending on whether the sensor is pressed or released. The control unit 150 can control the drive unit 5 based on the detection results of the first and second container sensors 7L and 7R. The first container sensor 7L is pressed by the first recovered developer container 10L when the first recovered developer container 10L is placed at a predetermined position inside the apparatus main body 110, i.e., at a position where the first recovered developer discharge port 44bL and the first container receiving opening 12L communicate with each other. This allows the control unit 150 to detect that the first recovered developer container 10L has been placed at the predetermined position. Furthermore, when the first collected developer container 10L is moved (removed) from the predetermined position, the first container sensor 7L is released from the pressure of the first collected developer container 10L. This allows the control unit 150 to detect that the first collected developer container 10L has been moved from the predetermined position. Similarly, the control unit 150 can detect, based on a signal from the second container sensor 7R, that the second collected developer container 10R has been placed at the predetermined position or that the second collected developer container 10R has been moved from the predetermined position. Note that the container detection means is not limited to a mechanical switch, and may be configured, for example, with an optical sensor or the like.

[0058] In this embodiment, the first and second container facing portions 122L and 122R are provided with recovered developer detecting means for detecting whether the first and second recovered developer containers 10L and 10R are filled with recovered developer. (Full detection unit)First and second full sensors 8L and 8R are provided as full sensors. In this embodiment, the first and second full sensors 8L and 8R are configured as optical sensors that output signals to a control unit 150 (described later) (FIG. 11) that change depending on whether detection light is transmitted or not. The control unit 150 can control the drive unit 5 based on the detection results of the first and second full sensors 8L and 8R. In this embodiment, the first and second full sensors 8L and 8R each have a light-emitting unit that emits detection light and a light-receiving unit that can receive the detection light emitted from the detection sensor. When the first and second recovered developer containers 10L and 10R are placed at predetermined positions inside the device main body 110, a detection window (not shown) provided in each container that is capable of transmitting the detection light is positioned between the light-emitting unit and the light-receiving unit. The detection window is designed to receive recovered developer when a predetermined amount of recovered developer corresponding to a preset full state is stored inside the first and second recovered developer containers 10L and 10R. Therefore, when the first and second recovered developer containers 10L and 10R are full of recovered developer, the detection light of the first and second full sensors 8L and 8R is blocked by the recovered developer inside the detection window. This allows the control unit 150 to detect that the first and second recovered developer containers 10L and 10R are full of recovered developer. The recovered developer detection means is not limited to an optical sensor and may be composed of, for example, a weight sensor.

[0059] Furthermore, in this embodiment, the first and second container-facing portions 122L and 122R are provided with first and second retaining portions 9L and 9R as retaining means for preventing the first and second recovered developer containers 10L and 10R from accidentally moving in the removal direction. The first and second retaining portions 9L and 9R engage with engaging portions provided on the first and second recovered developer containers 10L and 10R, respectively, when the first and second recovered developer containers 10L and 10R are installed in their respective predetermined positions within the apparatus main body 110. The engagement between the first and second retaining portions 9L and 9R and the first and second recovered developer containers 10L and 10R is intended to prevent the first and second recovered developer containers 10L and 10R from moving primarily due to the biasing force of the shutter pressing spring. Therefore, this engagement can be easily released by the force applied by an operator to remove the first and second recovered developer containers 10L and 10R.

[0060] 4. Control mode 4-1.Configuration 11 is a schematic block diagram showing the control mode of the main parts of the image forming apparatus 100 of this embodiment. In this embodiment, a control unit 150 is provided in the apparatus body 110 of the image forming apparatus 100. The control unit 150 is configured to include a CPU 151 as an arithmetic control means which is a central element for performing arithmetic processing, a memory (storage medium) 152 such as RAM or ROM as a storage means, and an input / output circuit (not shown) that controls the input and output of signals between the control unit 150 and each part. The RAM, which is a rewritable memory, stores information input to the control unit 150, detected information, arithmetic results, etc., while the ROM stores control programs, pre-calculated data tables, etc. The CPU 151 and memory 152 such as RAM or ROM can transfer and read data to and from each other.

[0061] The control unit 150 is connected to each unit of the image forming unit G. The control unit 150 is also connected to the drive unit 5 of the developer recovery device 1, the first and second recovery drive units 6L and 6R, the first and second container sensors 7L and 7R, the first and second full sensors 8L and 8R, the discharge drive unit 126, and the like. The control unit 150 is also connected to an operation unit (operation panel) 130 provided in the image forming apparatus 100. The operation unit 130 has a display unit (image display unit) such as a liquid crystal panel as display means for displaying information under the control of the control unit 150, and an audio output unit for outputting information by voice. The operation unit 130 also has an input unit such as keys as input means for inputting information to the control unit 150 by operation by an operator such as a user or a service representative. The operation unit 130 may be configured with a touch panel having the functions of a display unit and an input unit. In addition, the control unit 150 may be connected to an external device (not shown) such as an image reading device (not shown) provided in the image forming apparatus 100 or connected to the image forming apparatus 100, or a personal computer connected to the image forming apparatus 100.

[0062] The control unit 150 can comprehensively control each unit of the image forming unit G (such as the motors of the various drive units and the power supplies of the various voltage application units) based on instructions and image information from the operation unit 130 of the image forming apparatus 100 or an external device, to perform image forming operations. The control unit 150 can also comprehensively control each unit of the developer recovery device 1 to perform operations such as transporting recovered developer to the first and second recovered developer containers 10L and 10R, and prompting replacement and installation of each container. The control unit 150 can also be considered to constitute a part of the developer recovery device 1.

[0063] 4-2. Notification operation The image forming apparatus 100 can perform a notification operation to induce replacement and installation of each of the collected developer containers 10L and 10R.

[0064] FIG. 18 is a front view of an example of the operation unit 130 of the image forming apparatus 100. The operation unit 130 includes an image display unit 131 that displays images based on instructions from the control unit 150 and an audio output unit 132 that generates audio based on instructions from the control unit 150. For example, when the control unit 150 detects that the first collected developer container 10L has been removed, the control unit 150 can perform the following control. That is, the control unit 150 can prompt the user (operator) to install the first collected developer container 10L into the first container mounting portion 119L using audio, image display, or both, via the operation unit 130. The control unit 150 can prompt the user to install the missing collected developer container using the aforementioned identification indicator corresponding to the collected developer container to be installed (the missing collected developer container) via the image display unit 131. For example, the control unit 150 can display a message saying, "Please install the left container (container 1)." A similar audio message can also be generated by the audio output unit 132. Furthermore, when the control unit 150 detects that the first collected developer container 10L is full, the control unit 150 can prompt the user to replace the first collected developer container 10L using audio, image display, or both, via the operation unit 130. The control unit 150 can prompt the user to replace the collected developer container by using the above-mentioned identification mark (here, the first identification mark 121L) corresponding to the collected developer container to be replaced (the full collected developer container) via the image display unit 131. For example, the control unit 150 displays a message such as "Please replace the left container (container 1)." A similar audio message can also be generated by the audio output unit 132. Note that instead of or in combination with the above-mentioned notification, the image display unit 131 may display a video showing the location of the collected developer container 10L to be installed or replaced and the installation operation. The same procedure can be used to prompt the user to install or replace the second collected developer container 10L.

[0065] FIG. 19 is a front view of an example of the configuration of the first and second container mounting portions 119L and 119R of the image forming apparatus 100. The image forming apparatus 100 includes a first light-emitting portion 95L and a second light-emitting portion 95R at positions associated with (corresponding to) the first collected developer container 10L and the second collected developer container 10R, respectively. In this example, the first and second light-emitting portions 95L and 95R are provided on a panel 123 facing forward, at positions adjacent to and above the first and second container mounting portions 119L and 119R, respectively, in an area that at least partially overlaps with the first and second container mounting portions 119L and 119R in the left-right direction. For example, when the control unit 150 detects that the first collected developer container 10L has been removed, it can cause the first light-emitting portion 95L to emit light to prompt the user to mount the first collected developer container 10L into the first container mounting portion 119L. At this time, the second light-emitting unit 95R does not emit light. Furthermore, for example, when the control unit 150 detects that the first collected developer container 10L is full, the control unit 150 can make the first light-emitting unit 95L emit light to urge the user to replace the first collected developer container 10L. At this time, the second light-emitting unit 95R does not emit light. The same can be done for the second collected developer container 10R to urge the user to install or replace the second collected developer container 10L.

[0066] Although the notification by the light emitting units 95L and 95R and the operation unit 130 has been described here, the notification may be performed by either one of them.

[0067] 5. Operation of the developer recovery device Next, the operation of transporting recovered developer to the first and second recovered developer containers 10L and 10R by the developer recovery device 1 of this embodiment will be described. Here, the operation of the developer recovery device 1 when transporting recovered developer to each of the first and second recovered developer containers 10L and 10R will be described. A specific example of the operation sequence of the developer recovery device 1, including switching the destination of the recovered developer, will be described later.

[0068] Table 1 summarizes the operating states of the drive unit 5 and the first and second recovery drive units 6L and 6R in the operation of transporting recovered developer to the first and second recovered developer containers 10L and 10R in this embodiment. This operation is performed by the control unit 150 controlling the drive unit 5 and the first and second recovery drive units 6L and 6R in accordance with a program stored in memory 152.

[0069] [Table 1]

[0070] <Transportation Operation to First Collected Developer Container 10L> FIG. 9 shows the flow of recovered developer when it is transported to the first recovered developer container 10L on the left side. As described above, the developer recovery device 1 transports recovered developer from the image forming unit G to the downstream transport unit 4 via the upstream transport unit 3. The recovered developer transported to the downstream transport unit 4 moves through the vertical pipe 41 and into the horizontal pipe 42. When transporting recovered developer to the first recovered developer container 10L, the drive motor 51 of the drive unit 5 rotates forward, and the transport screw 43 in the horizontal pipe 42 receives driving force from the drive unit 5 and rotates in a first direction. As a result, the transport screw 43 transports the recovered developer in the horizontal pipe 42 from right to left. In response to the forward rotation of the drive motor 51 of the drive unit 5, the first recovery drive motor 61L (FIG. 7) of the first recovery drive unit 6L rotates, while the second recovery drive motor 61R (FIG. 6) of the second recovery drive unit 6R is stopped.

[0071] As a result, the recovered developer transported inside the horizontal pipe 42 by the transport screw 43 and sent to the first recovery pipe 44L is transported inside the first recovery pipe 44L by the first recovery screw 45L and sent to the first recovered developer container 10L. On the other hand, the recovered developer sent from the vertical pipe 41 to the horizontal pipe 42 is not transported in the direction from left to right inside the horizontal pipe 42. In addition, the recovered developer is not transported inside the second recovery pipe 44R.

[0072] Therefore, the image forming apparatus 1 00 Even if the developer recovery device 1 is removed from the apparatus main body 110 to replace the second recovered developer container 10R while the developer recovery device 1 is transporting recovered developer to the first recovered developer container 10L during operation (during image formation), it is possible to prevent the recovered developer from leaking or scattering from around the second recovered developer container 10R into the apparatus main body 110. That is, according to this embodiment, while the recovered developer is being transported to the first recovered developer container 10L, the recovered developer sent from the image forming unit G does not pass through the transport path toward the second recovered developer container 10R. Therefore, even if the second recovered developer container 10R is removed, it is possible to reduce the risk of the recovered developer leaking or scattering from the transport path toward the second recovered developer container 10R.

[0073] In this embodiment, a second shutter member 46R is provided on the second recovery pipe 44R, but due to the effect of reducing the risk of leakage or scattering of the recovered developer as described above, it is possible to omit this shutter member or simplify its configuration.

[0074] <Transportation Operation to Second Collected Developer Container 10R> FIG. 10 shows the flow of recovered developer when it is transported to the second recovered developer container 10R on the right side. As described above, the developer recovery device 1 transports recovered developer from the image forming unit G to the downstream transport unit 4 via the upstream transport unit 3. The recovered developer transported to the downstream transport unit 4 moves through the vertical pipe 41 and into the horizontal pipe 42. When transporting recovered developer to the second recovered developer container 10R, the drive motor 51 of the drive unit 5 rotates in the reverse direction, and the transport screw 43 in the horizontal pipe 42 receives driving force from the drive unit 5 and rotates in the second direction. As a result, the transport screw 43 transports the recovered developer in the horizontal pipe 42 from left to right. In response to the reverse rotation of the drive motor 51 of the drive unit 5, the second recovery drive motor 61R (FIG. 6) of the second recovery drive unit 6R rotates, while the first recovery drive motor 61L (FIG. 7) of the first recovery drive unit 6L is stopped.

[0075] As a result, the recovered developer transported inside the horizontal pipe 42 by the transport screw 43 and sent to the second recovery pipe 44R is transported inside the second recovery pipe 44R by the second recovery screw 45R and sent to the second recovered developer container 10R. On the other hand, the recovered developer sent from the vertical pipe 41 to the horizontal pipe 42 is not transported in the direction from right to left inside the horizontal pipe 42. In addition, the recovered developer is not transported inside the first recovery pipe 44L.

[0076] Therefore, the image forming apparatus 1 00 Even if the developer recovery device 1 is removed from the apparatus main body 110 to replace the first recovered developer container 10L while the developer recovery device 1 is transporting recovered developer to the second recovered developer container 10R during operation (during image formation), it is possible to prevent the recovered developer from leaking or scattering from around the first recovered developer container 10L into the apparatus main body 110. That is, according to this embodiment, while the recovered developer is being transported to the second recovered developer container 10R, the recovered developer sent from the image forming unit G does not pass through the transport path toward the first recovered developer container 10L. Therefore, even if the first recovered developer container 10L is removed, it is possible to reduce the risk of the recovered developer leaking or scattering from the transport path toward the first recovered developer container 10L.

[0077] In this embodiment, the first recovery pipe 44L is provided with a first shutter member 46L, but as with the second shutter member 46R, it is also possible to omit this shutter member or simplify its configuration.

[0078] As described above, the developer recovery device 1 includes a control unit 150 that controls the drive unit 5, the first recovery drive unit 6L, and the second recovery drive unit 6R. When the drive unit 5 drives the conveying screw 43 to rotate in the first direction, the control unit 150 performs control as follows. That is, the control unit 150 controls the first recovery drive unit 6L to rotate the first recovery screw 45L and stops the second recovery drive unit 6R to rotate the second recovery screw 45R. When the drive unit 5 drives the conveying screw 43 to rotate in the second direction, the control unit 150 performs control as follows. That is, the control unit 150 controls the first recovery drive unit 6L to stop the first recovery screw 45L to rotate and stops the second recovery drive unit 6R to rotate the second recovery screw 45R.

[0079] 6. Basic operation sequence of developer recovery device Next, a specific example of a basic operational sequence including switching the destination of the recovered developer in the developer recovery device 1 of this embodiment will be described. FIG. 12 is a flowchart showing the procedure of the operational sequence. For simplicity's sake, this section will describe the operation of switching the destination of the recovered developer during execution of a continuous image formation job, assuming that the first and second recovered developer containers 10L and 10R are located at predetermined positions inside the device main body 110. A job is a series of operations that start with a single start command and form and output images on one or more recording materials P. Although not described below, the control unit 150 also controls the operation of the first and second recovery drive units 6L and 6R (see Table 1) in conjunction with controlling the operation of the drive unit 5. Although not described below, the discharge screw 37 of the upstream transport unit 3 is continuously driven to rotate during the image formation operation and stops when the image formation operation is completed (or interrupted).

[0080] When a job is input and an image forming operation is started (S101), the control unit 150 determines whether the current destination of the collected developer is the first collected developer container 10L based on information stored in the memory 152 (S102). Note that, every time the control unit 150 switches the destination of the collected developer, it stores information about the current destination of the collected developer in the memory 152. If the control unit 150 determines in S102 that the current destination of the collected developer is not the first collected developer container 10L ("No"), it proceeds to the process of S112. If the control unit 150 determines in S102 that the current destination of the collected developer is the first collected developer container 10L ("Yes"), it causes the drive motor 51 of the drive unit 5 to rotate forward (S103). Next, the control unit 150 determines whether the first recovered developer container 10L is full (whether the signal from the first full sensor 8L is ON) based on the signal from the first full sensor 8L (S104). If the control unit 150 determines in S104 that the first recovered developer container 10L is not full ("No"), the control unit 150 continues the image forming operation (S105). Next, the control unit 150 determines whether there are any images in the job that have not been output (S106). If the control unit 150 determines in S106 that there are any images that have not been output ("Yes"), the control unit 150 returns to the process of S104, and if the control unit 150 determines that there are no images that have not been output ("No") in S106, the control unit 150 stops the drive motor 51 of the drive unit 5 (S107). The control unit 150 also ends the image forming operation and ends the job (S108). Furthermore, if the control unit 150 determines in S104 that the second collected developer container 10R is full ("Yes"), it determines whether the second collected developer container 10R is full (whether the signal from the second full sensor 8R is ON) based on the signal from the second full sensor 8R (S109). If the control unit 150 determines in S109 that the second collected developer container 10R is full ("Yes"), it stops the drive motor 51 of the drive unit 5 (S110). Furthermore, the control unit 150 suspends the image forming operation (S111). In S111, the control unit 150 can display, for example, on the operation unit 130 (or a display unit of an external device) to notify the user that both the first and second collected developer containers 10L, 10R are full.

[0081] On the other hand, if the control unit 150 determines in S109 that the second collected developer container 10R is not full ("No"), it switches the rotation direction of the drive motor 51 of the drive unit 5 to rotate in the reverse direction (S112). As a result, the destination of the collected developer is switched from the first collected developer container 10L to the second collected developer container 10R. Note that even if the control unit 150 determines in S102 that the current destination of the collected developer is not the first collected developer container 10L ("No"), it also rotates the drive motor 51 of the drive unit 5 in the reverse direction (S112). Next, the control unit 150 determines whether the second collected developer container 10R is full (whether the signal from the second full sensor 8R is ON) based on the signal from the second full sensor 8R (S113). If the control unit 150 determines in S113 that the second collected developer container 10R is not full ("No"), it continues the image forming operation (S114). Next, the control unit 150 determines whether there are any unoutput images of the job (S115). If the control unit 150 determines in S115 that there are any unoutput images ("Yes"), it returns to the process of S113, and if the control unit 150 determines that there are no unoutput images ("No") in S115, it stops the drive motor 51 of the drive unit 5 (S116). Furthermore, the control unit 150 ends the image forming operation and ends the job (S117). Furthermore, if the control unit 150 determines that the first recovered developer container 10L is full ("Yes") in S113, it determines whether the first recovered developer container 10L is full (whether the signal from the first full sensor 8L is ON) based on the signal from the first full sensor 8L (S118). If the control unit 150 determines that the first recovered developer container 10L is not full ("No") in S118, it proceeds to the process of S103. That is, the control unit 150 switches the rotation direction of the drive motor 51 of the drive unit 5 to rotate it forward, and switches the destination of the collected developer from the second collected developer container 10R to the first collected developer container 10L. If the control unit 150 determines in S118 that the containers are full ("Yes"), it stops the drive motor 51 of the drive unit 5 (S119). The control unit 150 also suspends the image forming operation (S120). In S120, the control unit 150 can display, for example, on the operation unit 130 (or a display unit of an external device) to notify the user that both the first and second collected developer containers 10L, 10R are full.

[0082] Furthermore, when the rotation direction of the drive motor 51 of the drive unit 5 is switched in S112 and S103 to switch the container to which the recovered developer is transported, the control unit 150 can perform the following control: That is, the control unit 150 can display, for example, on the operation unit 130 (or the display unit of the external device, etc.), a message that the full container needs to be replaced (such as a message urging the replacement).

[0083] Although not described here for simplicity, the control unit 150 can control the image forming operation and the operation of the developer recovery device 1 based on signals from the first and second container sensors 7L and 7R. For example, when the control unit 150 determines that both the first and second recovered developer containers 10L and 10R are not installed when a job start command is received, the control unit 150 can control the image forming operation not to start. Furthermore, for example, when the control unit 150 detects that one of the first and second recovered developer containers 10L and 10R is full and then detects that the other container is not installed, the control unit 150 can control the image forming operation to be interrupted. In either case, a display prompting the user to install the corresponding container can be displayed on the operation unit 130 (or a display unit of an external device, etc.). A specific example will be described below in further detail.

[0084] In this manner, in this embodiment, when one of the first and second recovered developer containers 10L and 10R becomes full, the recovered developer is transferred to the other container, and the first and second recovered developer containers 10L and 10R are used alternately. This allows one container to be replaced without stopping the image formation operation, even if it becomes full during the image formation operation. According to this embodiment, even when replacing one container during the image formation operation, it is possible to prevent the recovered developer from leaking or scattering around the container into the apparatus main body 110.

[0085] 7. Outline of operation when the destination of the recovered developer container is removed Next, an outline of the operation of the developer recovery device 1 of this embodiment when the recovered developer containers 10L and 10R to which the recovered developer is being transported during an image forming operation are removed will be described. Note that the specific operation when the recovered developer containers 10L and 10R to which the recovered developer is being transported during an image forming operation in this embodiment are removed will be described later.

[0086] When recovered developer is being transported to the first recovered developer container 10L on the left side during image formation, the drive motor 51 of the drive unit 5 rotates in the forward direction (FIG. 9, Table 1). The first recovery drive motor 61L of the first recovery drive unit 6L is operating (FIG. 9, Table 1). The second recovery drive motor 61R of the second recovery drive unit 6R is stopped (FIG. 9, Table 1). If the first recovered developer container 10L is removed at this time, the first container sensor 7L detects that the container has been removed. Then, the rotation of the drive motor 51 of the drive unit 5 is switched from the forward direction to the reverse direction. In conjunction with the switching of the rotation of the drive motor 51 of the drive unit 5, the operation of the first recovery drive motor 61L of the first recovery drive unit 6L is stopped. In conjunction with the switching of the rotation of the drive motor 51 of the drive unit 5, the operation of the second recovery drive motor 61R of the second recovery drive unit 6R is started. In this embodiment, when the first recovered developer container 10L is removed, the first shutter member 46L is closed. As a result, even if the first recovered developer container 10L, to which the recovered developer is being transported, is removed during image formation, the recovered developer sent from the vertical pipe 41 to the horizontal pipe 42 will not be transported in the direction from right to left within the horizontal pipe 42. In addition, the recovered developer will not be transported within the first recovery pipe 44L.

[0087] When recovered developer is being transported to the second recovered developer container 10R on the right side during image formation, the drive motor 51 of the drive unit 5 rotates in reverse (FIG. 10, Table 1). The second recovery drive motor 61R of the second recovery drive unit 6R operates (FIG. 10, Table 1). The first recovery drive motor 61L of the first recovery drive unit 6L is stopped (FIG. 10, Table 1). If the second recovered developer container 10R is removed at this time, the second container sensor 7R detects that the container has been removed. Then, the rotation of the drive motor 51 of the drive unit 5 is switched from reverse to forward. In conjunction with this switch in the rotation of the drive motor 51 of the drive unit 5, the operation of the second recovery drive motor 61R of the second recovery drive unit 6R is stopped. In addition, in conjunction with switching of the rotation operation of the drive motor 51 of the drive unit 5, the operation of the first recovery drive motor 61L of the first recovery drive unit 6L is started. In addition, in this embodiment, when the second recovered developer container 10R is removed, the second shutter member 46R is closed. As a result, even if the second recovered developer container 10R, to which the recovered developer is being transported, is removed during image formation operation, the recovered developer sent from the vertical pipe 41 to the horizontal pipe 42 will not be transported in the direction from left to right within the horizontal pipe 42. In addition, the recovered developer will not be transported within the second recovery pipe 44R.

[0088] 13 is a flowchart showing the basic operation sequence of the developer recovery device 1 during continuous image forming operations, incorporating the operation of switching the transport direction of the recovered developer when the recovered developer containers 10L and 10R are removed as described above. Note that, although not described below, the control unit 150 also controls the operations of the first and second recovery drive units 6L and 6R as described above in conjunction with the control of the operation of the drive unit 5 (see Table 1). Also, although not described below, the discharge screw 37 of the upstream transport unit 3 is continuously driven to rotate during the image forming operation and is stopped when the image forming operation is completed (or interrupted).

[0089] In the procedure of Fig. 13, the same processes as in the procedure of Fig. 12 are assigned the same step numbers (S101 to S120). The procedure of Fig. 13 includes processes of S501 to S504 in addition to the processes (S101 to S120) in the procedure of Fig. 12. Here, the description of the processes described with reference to Fig. 12 will be omitted as appropriate, and the description will mainly focus on the processes added to the procedure of Fig. 13.

[0090] When the control unit 150 causes the drive motor 51 of the drive unit 5 to rotate forward in S103, the control unit 150 determines whether the first collected developer container 10L is attached (whether the signal from the first container sensor 7L is ON or not) based on the signal from the first container sensor 7L (S501). If the control unit 150 determines in S501 that the first collected developer container 10L is attached ("Yes"), the control unit 150 proceeds to the processing of S104. On the other hand, if the control unit 150 determines in S501 that the first collected developer container 10L is not attached ("No"), the control unit 150 performs the following control. That is, the control unit 150 determines whether the second collected developer container 10R is attached (whether the signal from the second container sensor 7R is ON or not) based on the signal from the second container sensor 7R (S502). If the control unit 150 determines in S502 that the second collected developer container 10R is installed ("Yes"), it proceeds to the process of S109. That is, in this case, as described above, if the second collected developer container 10R is not full, the destination of the collected developer is switched from the first collected developer container 10L to the second collected developer 10R. On the other hand, if the control unit 150 determines in S502 that the second collected developer container 10R is not installed ("No"), it proceeds to the process of S110. That is, in this case, as described above, the image forming operation is interrupted.

[0091] Furthermore, when the control unit 150 reversely rotates the drive motor 51 of the drive unit 5 in S112, the control unit 150 determines whether the second collected developer container 10R is attached (whether the signal from the second container sensor 7R is ON or not) based on the signal from the second container sensor 7R (S503). If the control unit 150 determines in S503 that the second collected developer container 10R is attached ("Yes"), the control unit 150 proceeds to the processing of S113. On the other hand, if the control unit 150 determines in S503 that the second collected developer container 10R is not attached ("No"), the control unit 150 performs the following control. That is, the control unit 150 determines whether the first collected developer container 10L is attached (whether the signal from the first container sensor 7L is ON or not) based on the signal from the first container sensor 7L (S504). If the control unit 150 determines in S504 that the first collected developer container 10L is installed ("Yes"), it proceeds to the process of S118. That is, in this case, as described above, if the first collected developer container 10L is not full, the destination of the collected developer is switched from the second collected developer container 10R to the first collected developer 10L. On the other hand, if the control unit 150 determines in S504 that the first collected developer container 10L is not installed ("No"), it proceeds to the process of S119. That is, in this case, as described above, the image forming operation is interrupted.

[0092] 8. Specific operation when the destination recovered developer container in this embodiment is removed As described above, in an image forming apparatus equipped with a developer recovery device capable of switching the destination of recovered developer, there may be cases where the recovered developer container to which the recovered developer is being transported is inadvertently removed during image formation. For example, when recovered developer is being transported to the first of the first and second recovered developer containers and the second recovered developer container is full inside the apparatus body, the first recovered developer container may be inadvertently pulled out of the apparatus body. However, in such a case, if the image forming operation is immediately stopped according to the operational sequence shown in FIG. 13, productivity may be hindered. The same applies, for example, to a case where one of the first and second recovered developer containers is inadvertently pulled out of the apparatus body while recovered developer is being transported to the first of the first and second recovered developer containers. Furthermore, for example, when recovered developer is being transported to the first recovered developer container out of the first and second recovered developer containers and the second recovered developer container is empty and inside the device body, it is conceivable that the first recovered developer container may be inadvertently pulled out of the device body. In such a case, if the destination of the recovered developer is immediately switched to the second recovered developer container according to, for example, the operational sequence shown in FIG. 13, this may hinder the efficient use of the recovered developer container. Therefore, it is conceivable to provide a configuration such as a locking means to prevent (lock) the recovered developer container to which the recovered developer is being transported from being inadvertently pulled out. However, such a configuration leads to increased complexity and cost of the device, so it is desirable to omit or simplify it.

[0093] Therefore, in this embodiment, the image forming operation continues for a predetermined time even if the recovered developer container to which the recovered developer is being transported is inadvertently removed from the apparatus main body 110 during the image forming operation. After the predetermined time has elapsed, the user can select whether to continue the image forming operation without switching the destination of the recovered developer, to switch the destination of the recovered developer and continue the image forming operation, or to stop the image forming operation.

[0094] In other words, in a configuration that does not include a mechanism for preventing (locking) the recovered developer container from being accidentally pulled out, it is possible that a recovered developer container that is the current destination of the recovered developer and is not the one to be replaced may be accidentally removed. In this embodiment, even in such a case, the image forming operation continues for a predetermined time without immediately stopping the operation of the image forming apparatus 100. If the accidentally removed recovered developer container is returned within the predetermined time, the recovered developer can be continuously transported to that recovered developer container. In this embodiment, if a recovered developer container being filled with recovered developer is removed during image formation, the driving of the transport means for filling the recovered developer is stopped, and the recovered developer is temporarily stored in the transport path. Thereafter, the destination for the recovered developer is selected based on the installation status of the recovered developer container and the filled status of the recovered developer in the recovered developer container. If a recovered developer container being filled with recovered developer is removed during an image formation operation, and the removed recovered developer container is reattached within a predetermined time and the recovered developer container is still refillable, the system resumes refilling the recovered developer into that recovered developer container. Also, if a recovered developer container being filled during an image formation operation is removed but not reattached within a predetermined time and another installed recovered developer container is still refillable, the system switches the refill destination of the recovered developer to the other installed recovered developer container. This starts refilling the recovered developer into a refillable recovered developer container. Thus, in this embodiment, in a configuration with multiple recovered developer containers, if a recovered developer container being filled with recovered developer is removed due to erroneous operation, the system stops driving the conveying means for refilling the recovered developer, and temporarily stores the recovered developer in the conveying path. The conveying destination is then selected based on the status (installed / filled) of the recovered developer container.

[0095] 9. Specific Operation Procedure in the Case Where the Received Developer Container of the Destination in the Present Embodiment is Removed Next, a specific operation procedure of the developer recovery device 1 of this embodiment when the recovered developer containers 10L and 10R, to which recovered developer is being transported, are removed during image formation operation will be described. This operation is performed by the control unit 150 controlling the drive unit 5 (drive motor 51), the first and second recovery drive units 6L and 6R (first and second recovery drive motors 61L and 61R), etc. in accordance with a program stored in the memory 152.

[0096] <When the first recovered developer container 10L, which is the destination of the recovered developer, is removed> 14 is a flowchart showing the procedure of the operation when the first collected developer container 10L is removed when the destination of the collected developer is the first collected developer container 10L. Here, the explanation focuses on the operation triggered by the removal of the first collected developer container 10L to which the collected developer is being transported during an image forming operation.

[0097] When the first collected developer container 10L is removed from the apparatus main body 110 while a job is input, an image forming operation is in progress, and the destination of the collected developer is the first collected developer container 10L (S201), the control unit 150 performs control as follows: While continuing the image forming operation, the control unit 150 determines whether the first collected developer container 10L has been reinstalled (whether the signal from the first container sensor 7L is ON) (S202). When the control unit 150 determines in S202 that the first collected developer container 10L has not been reinstalled ("No"), it stops the operation of the drive motor 51 of the drive unit 5 and the first collection drive motor 61L of the first collection drive unit 6L (S203). In the process of S203 again, if the operation of the drive motor 51 of the drive unit 5 and the first collection drive motor 61L of the first collection drive unit 6L has already been stopped in the previous process of S203, the control unit 150 maintains that state. Next, the control unit 150 determines whether or not one minute has elapsed as a predetermined time (S204). If the control unit 150 determines in S204 that one minute has not elapsed ("No"), the control unit 150 returns to the process of S202. On the other hand, if the control unit 150 determines in S204 that one minute has elapsed ("Yes"), the control unit 150 proceeds to the process of S208. In this way, the control unit 150 repeatedly determines whether or not the first collected developer container 10L has been reattached based on the signal from the first container sensor 7L during the predetermined time of one minute (S202 to S204).

[0098] In this embodiment, the predetermined time for repeatedly determining whether the first recovered developer container 10L, which is the destination of the recovered developer, has been reattached when the first recovered developer container 10L is removed is set to one minute, as described above. However, this predetermined time is not limited to the value in this embodiment. This predetermined time is longer than the time it takes for the control unit 150 to switch the destination of the recovered developer to another recovered developer container when one container becomes full, for example, according to the operation sequence shown in FIG. 13 . On the other hand, setting this predetermined time excessively long (i.e., setting an excessively large buffer capacity for recovered developer when the transport of recovered developer to the recovered developer container is stopped) may affect the miniaturization of the device. In the configuration of this embodiment, the time it takes for the control unit 150 to switch the destination of the recovered developer when the container is full can be represented by the time it takes for the control unit 150 to output a signal to switch the rotation direction of the drive motor 51 in response to a signal from a fullness sensor or the like. In the configuration of this embodiment, this time is very short, for example, on the order of milliseconds. In addition, in the configuration of this embodiment, the time required for the recovered developer transport direction to actually switch is approximately 1.6 seconds due to the start and stop of the drive motor 51. In the configuration of this embodiment, this time can be represented by the time from when the transport screw 47 starts to stop rotating in one direction until it starts rotating in the other direction and becomes capable of transporting the recovered developer. Although not limited to this, it is preferable that the predetermined time be set to 2 seconds or more, and typically 30 seconds or more. On the other hand, although not limited to this, it is preferable that the predetermined time be set to 5 minutes or less, and typically 3 minutes or less. For example, the above-mentioned range of time is often sufficient for an operator who mistakenly pulls out a recovered developer container to which the recovered developer is to be transported to reattach that container.

[0099] The control unit 150 may also be capable of changing the predetermined time period based on information regarding the amount of developer used by the image forming unit G to form an image during the image formation operation. One example of the information regarding the amount of developer is information regarding image density. For example, the control unit 150 may control the predetermined time period to be changed based on information regarding the image density of the image to be formed in the job. The information regarding image density may be the average value of the image density of the image to be formed in the job. For example, the average value of the image density of the image until the recovered developer container to which the recovered developer is transported is removed (such as the average value of the most recent predetermined number of images formed, which affects the buffer capacity based on the configuration of the recovered developer transport path, etc.) may be used. The control unit 150 may set the predetermined time period to a first time period (e.g., one minute) when the image density is a first value, and to a second time period (e.g., 30 seconds) shorter than the first time period when the image density is a second value higher than the first value. The information regarding the amount of developer is not limited to information regarding image density, but may also be information regarding the image ratio (print rate, image duty), etc. Furthermore, for example, an operator such as a user may be able to arbitrarily set the predetermined time based on the tendency of the image the user forms, etc. In this case, the control unit 150 can store in the memory 152 information about the predetermined time input from the operation unit 130, which serves as a setting unit that sets the predetermined time in response to the operation of the operator, and use the information.

[0100] In this embodiment, in S203, the control unit 150 stops the operation of the drive motor 51 of the drive unit 5 and the first recovery drive motor 61L of the first recovery drive unit 6L as described above. Meanwhile, in this embodiment, in S203, the control unit 150 continues the operation of the discharge drive motor (not shown) of the discharge drive unit 126 that drives the discharge screw 37 of the upstream conveying unit 3. In this embodiment, the first to fifth discharge pipes 31 to 35, the main discharge pipe 36, and the vertical pipe 41 are used as buffers for storing recovered developer discharged from the image forming unit G (the drum cleaning device 106 and the developing device 104 of each station S, and the belt cleaning device 109). However, the present invention is not limited to an embodiment in which the discharge screw 37 of the upstream conveying unit 3 continues to operate during the predetermined time. The operation of the discharge screw 37 of the upstream conveying unit 3 may be stopped for at least a portion of the predetermined time. For example, depending on the configuration of the recovered developer transport path including the first to fifth discharge pipes 31 to 35 leading to the main discharge pipe 36, the discharge screw 37 may be stopped during the predetermined time.

[0101] If the control unit 150 determines in S202 that the first collected developer container 10L has been re-installed within the predetermined time (within one minute) (“Yes”), the control unit 150 performs the following control. That is, the control unit 150 determines whether the first collected developer container 10L is full (whether the signal from the first full sensor 8L is ON) based on the signal from the first full sensor 8L (S205). If the control unit 150 determines that the first collected developer container 10L is not full (“No”) in S205, the control unit 150 performs the following control. That is, the control unit 150 resumes the forward rotation of the drive motor 51 of the drive unit 5 and the rotation of the first collection drive motor 61L of the first collection drive unit 6L (S206), and transports the collected developer to the first collected developer container 10L to continue the image forming operation (S207). On the other hand, if the control unit 150 determines that the first collected developer container 10L is full (“Yes”) in S205, the control unit 150 proceeds to the process of S208.

[0102] If the first collected developer container 10L is not re-installed within the predetermined time (within one minute), i.e., if it is determined in S204 that one minute has elapsed ("Yes"), the control unit 150 performs the following control. That is, the control unit 150 determines whether the second collected developer container 10R is installed (whether the signal from the second container sensor 7R is ON) based on the signal from the second container sensor 7R (S208). In addition, the control unit 150 also executes the process of S208 when it is determined in S205 that the first collected developer container 10L is full ("Yes"). If it is determined in S208 that the second collected developer container 10R is not installed ("No"), the control unit 150 stops the operation of the image forming apparatus 100 (stops the image forming operation) (S209). On the other hand, if the control unit 150 determines in S208 that the second collected developer container 10R is attached ("Yes"), it performs the following control. That is, the control unit 150 determines whether the second collected developer container 10R is full (whether the signal from the second full sensor 8R is ON) based on the signal from the second full sensor 8R (S210). If the control unit 150 determines in S210 that the second collected developer container 10R is not full ("No"), it performs the following control. That is, the control unit 150 starts the reverse rotation of the drive motor 51 of the drive unit 5 and the rotation of the second collection drive motor 61R of the second collection drive unit 6R (S211), and transports the collected developer to the second collected developer container 10R to continue the image forming operation (S212). On the other hand, if the control unit 150 determines in S210 that the tray is full ("Yes"), it stops the operation of the image forming apparatus 100 (stops the image forming operation) (S209).

[0103] <When the second collected developer container 10R, which is the destination of the collected developer, is removed> 15 is a flowchart showing the procedure of the operation when the second collected developer container 10R is removed when the destination of the collected developer is the second collected developer container 10R. Here, the explanation focuses on the operation triggered by the removal of the second collected developer container 10R to which the collected developer is being transported during an image forming operation.

[0104] When the second collected developer container 10R is removed from the apparatus main body 110 while a job is input, an image forming operation is in progress, and the destination of the collected developer is the second collected developer container 10R (S301), the control unit 150 performs control as follows: While continuing the image forming operation, the control unit 150 determines whether the second collected developer container 10R has been reinstalled (whether the signal from the second container sensor 7R is ON or not) (S302). When the control unit 150 determines in S302 that the second collected developer container 10R has not been reinstalled ("No"), it stops the operation of the drive motor 51 of the drive unit 5 and the second collection drive motor 61R of the second collection drive unit 6R (S303). In the process of S303 again, if the operation of the drive motor 51 of the drive unit 5 and the second collection drive motor 61R of the second collection drive unit 6R has already been stopped in the previous process of S303, the control unit 150 maintains that state. Next, the control unit 150 determines whether or not one minute has elapsed as a preset predetermined time (S304). If the control unit 150 determines in S304 that one minute has not elapsed ("No"), the control unit 150 returns to the process of S302. On the other hand, if the control unit 150 determines in S304 that one minute has elapsed ("Yes"), the control unit 150 proceeds to the process of S308. In this way, the control unit 150 repeatedly determines whether or not the second collected developer container 10R has been reattached based on the signal from the second container sensor 7R during the predetermined time of one minute (S302 to S304).

[0105] In this embodiment, the predetermined time for repeatedly determining whether the second collected developer container 10R, which is the destination of the collected developer, has been reattached when the second collected developer container 10R has been removed is set to one minute as described above. However, as in the case of the first collected developer container 10L described above, this predetermined time is not limited to the value in this embodiment.

[0106] As in the case of the first recovered developer container 10L, the control unit 150 may change the predetermined time based on information regarding the amount of developer used by the image forming unit G to form an image in the image forming operation. For example, the control unit 150 may control the predetermined time to be changed based on information regarding the image density of the image to be formed in the job. When the image density is a third value, the control unit 150 may set the predetermined time to a third time (e.g., 1 minute), and when the image density is a fourth value higher than the third value, the control unit 150 may set the predetermined time to a fourth time (e.g., 30 seconds) that is shorter than the third time. Note that when the third value and the fourth value are the same as the first value and the second value, respectively, the third time and the fourth time may be the same as the first time and the second time, respectively. Furthermore, the predetermined time may be different when the first recovered developer container 10L is removed from the predetermined time when the second recovered developer container 10R is removed. As in the case of the first recovered developer container 10L, the predetermined time may be set arbitrarily.

[0107] Also, in this embodiment, in S303, the control unit 150 stops the operation of the drive motor 51 of the drive unit 5 and the second collection drive motor 61R of the second collection drive unit 6R as described above. On the other hand, in this embodiment, in S303, the control unit 150 continues the operation of the discharge drive motor (not shown) of the discharge drive unit 126 that drives the discharge screw 37 of the upstream conveying unit 3. However, as in the case of the first collected developer container 10L described above, the operation of the discharge screw 37 of the upstream conveying unit 3 may be stopped for at least a part of the predetermined time.

[0108] If the control unit 150 determines in S302 that the second collected developer container 10R has been re-installed within the predetermined time (within one minute) (“Yes”), it performs the following control. That is, the control unit 150 determines whether the second collected developer container 10R is full (whether the signal from the second full sensor 8R is ON) based on the signal from the second full sensor 8R (S305). If the control unit 150 determines in S205 that the second collected developer container 10R is not full (“No”), it performs the following control. That is, the control unit 150 resumes the reverse rotation of the drive motor 51 of the drive unit 5 and the rotation of the second collection drive motor 61R of the second collection drive unit 6R (S306), and transports the collected developer to the second collected developer container 10R to continue the image forming operation (S307). On the other hand, if the control unit 150 determines in S305 that the second collected developer container 10R is full (“Yes”), it proceeds to the process of S308.

[0109] If the second collected developer container 10R is not re-installed within the predetermined time (within one minute), i.e., if it is determined in S304 that one minute has elapsed ("Yes"), the control unit 150 performs the following control. That is, the control unit 150 determines whether the first collected developer container 10L is installed (whether the signal from the first container sensor 7L is ON) based on the signal from the first container sensor 7L (S308). In addition, if the control unit 150 determines in S305 that the second collected developer container 10R is full ("Yes"), it also executes the process of S308. If it determines in S308 that the first collected developer container 10L is not installed ("No"), the control unit 150 stops the operation of the image forming apparatus 100 (stops the image forming operation) (S309). On the other hand, if the control unit 150 determines in S308 that the first collected developer container 10L is attached ("Yes"), it performs the following control. That is, the control unit 150 determines whether the first collected developer container 10L is full (whether the signal from the first full sensor 8L is ON) based on the signal from the first full sensor 8L (S310). If the control unit 150 determines in S310 that the first collected developer container 10L is not full ("No"), it performs the following control. That is, the control unit 150 starts the forward rotation of the drive motor 51 of the drive unit 5 and the rotation of the first collection drive motor 61L of the first collection drive unit 6L (S311), and transports the collected developer to the first collected developer container 10L to continue the image forming operation (S312). On the other hand, if the control unit 150 determines in S310 that the image forming apparatus 100 is full ("Yes"), it stops the operation of the image forming apparatus 100 (stops the image forming operation) (S309).

[0110] In this embodiment, the operation of the developer recovery device 1 having the first and second recovery pipes 44L and 44R when the recovered developer containers 10L and 10R to which the recovered developer is being transported during image formation has been described. However, the developer recovery device 1 may be configured so that the recovered developer is sent directly to the first and second recovered developer containers 10L and 10R from the horizontal pipe 42. In the developer recovery device 1 having this configuration, the first and second recovery drive units 6L and 6R are not present, so that the operation of the drive unit 5 can be controlled in the same manner as described above at S203, S206, and S211 in FIG. 14 and S303, S306, and S311 in FIG. 15.

[0111] As described above, in this embodiment, the developer recovery device 1 does not have a structure for preventing (locking) the recovered developer container containing the recovered developer from being inadvertently pulled out. With this simple structure, even if the recovered developer container containing the recovered developer is accidentally removed, the image forming operation of the image forming apparatus 100 can be continued for a predetermined time without immediately stopping the operation. After the predetermined time has elapsed, the image forming operation can be continued without switching the destination of the recovered developer, or the image forming operation can be stopped. Therefore, according to this embodiment, even if the recovered developer container containing the recovered developer is removed, it is possible to suppress a decrease in productivity and efficiently use the recovered developer container.

[0112] [others] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-described embodiments.

[0113] In the above-described embodiment, the developer recovery device 1 is configured such that the first and second recovery screws 45L and 45R are each rotationally driven by a drive unit (drive source) separate from the conveying screw 43. However, the present invention is not limited to such an embodiment. For example, as shown in FIG. 16, the developer recovery device 1 may be configured such that the first and second recovery screws 45L and 45R are rotationally driven by a drive force transmitted to the conveying screw 43. In the developer recovery device 1 shown in FIG. 16, elements having the same or corresponding functions or configurations as those in the above-described embodiment are denoted by the same reference numerals as in the above-described embodiment. In the developer recovery device 1 shown in FIG. 16, the conveying screw 43 is rotationally driven by a rotational drive force transmitted from a drive unit 5. The drive unit 5 is configured to include a drive motor 51 as a drive source and a drive train (e.g., one or more gears) 52 that transmits the drive force from the drive motor 51 to the conveying screw 43. In addition, first and second drive transmission units 20L and 20R are provided so as to be drivingly coupled to shaft portions at the left and right ends of the conveying screw 43 in the direction of its rotation axis. Each of the first and second drive transmission units 20L and 20R has a drive train including a one-way clutch gear as a drive force interrupting member. The first drive transmission unit 20L is configured to transmit drive force to the first recovery screw 45L when the conveying screw 43 rotates in a first direction (a direction in which the collected developer is conveyed toward the first collected developer container 10L). The second drive transmission unit 20R is configured to interrupt transmission of drive force to the second recovery screw 43R at this time. The second drive transmission unit 20R is configured to transmit drive force to the second recovery screw 45R when the conveying screw 43 rotates in a second direction (a direction in which the collected developer is conveyed toward the second collected developer container 10R), which is opposite to the first direction. At this time, the first drive transmission unit 20L is configured to cut off the transmission of drive force to the first collection screw 43L. The present invention can also be applied to a developer collection device 1 configured in this manner. In this case, it is not necessary to control the operations of the first and second collection drive units 6L and 6R in conjunction with the control of the operation of the drive unit 5 in the above-mentioned embodiment.

[0114] In the above-described embodiment, the developer recovery device 1 is configured to switch the direction of transport of the recovered developer inside the horizontal pipe 42 by switching the rotation direction of the transport screw 43, thereby switching the destination of the recovered developer between the first and second recovered developer containers 10L and 10R. As described above, this configuration makes it easier to prevent leakage and scattering of recovered developer associated with the attachment and detachment of the recovered developer with a simpler configuration. However, the present invention is not limited to this configuration. For example, as shown in FIG. 17, the developer recovery device 1 may be configured to transport the recovered developer inside the horizontal pipe 42 in one direction and switch the destination of the recovered developer by opening and closing a shutter member, etc. Note that in the developer recovery device 1 shown in FIG. 17, elements having the same or corresponding functions or configurations as those in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment. In the developer recovery device 1 shown in FIG. 17, the conveying screw 43 rotates in a predetermined direction to convey the recovered developer inside the horizontal pipe 42 leftward in the figure toward the first recovered developer container 10L and the second recovered developer container 10R. The horizontal pipe 42 is provided with a first horizontal pipe discharge port 42b through which the recovered developer is discharged toward the first recovered developer container 10L and a second horizontal pipe discharge port 42c through which the recovered developer is discharged toward the second recovered developer container 10R. The horizontal pipe 42 is also provided with first and second horizontal pipe shutters 47L and 47R that open and close the first and second horizontal pipe discharge ports 42b and 42c, respectively. The first and second horizontal pipe shutters 47L and 47R are configured to open and close by appropriate actuators. When the destination of the recovered developer is the first recovered developer container 10L, the control unit 150 controls the first horizontal pipe shutter 47L to be opened and the second horizontal pipe shutter 47R to be closed. On the other hand, when the destination of the recovered developer is the second recovered developer container 10R, the control unit 150 controls the first horizontal pipe shutter 47L to be closed and the second horizontal pipe shutter 47R to be opened. By stopping the driving of the conveying screw 43 and further closing the first and second horizontal pipe shutters 47L and 47R, it is possible to stop the conveyance of the developer to the first and second recovered developer containers 10L and 10R.Therefore, for example, in S203 in Fig. 14, the drive motor 51 of the drive unit 5 is stopped and the first and second horizontal pipe shutters 47L, 47R are closed. Also, in S206 and S211 in Fig. 14, the drive motor 51 of the drive unit 5 is restarted (started) and either the first or second horizontal pipe shutter 47L, 47R corresponding to the filling destination is opened. The same applies to the processing of S303, S306, and S311 in Fig. 15.

[0115] In the above-described embodiment, the image forming apparatus is a tandem-type color image forming apparatus employing an intermediate transfer system. However, the present invention is not limited to this. For example, the image forming apparatus may be a tandem-type color image forming apparatus employing a direct transfer system. As is well known to those skilled in the art, this image forming apparatus includes a recording material carrier (e.g., an endless conveying belt) that supports and transports a recording material, instead of the intermediate transfer member in the above-described embodiment. Then, toner images formed on the image carriers of multiple stations are sequentially transferred to the recording material carried and transported on the recording material carrier, fixed, and then discharged outside the image forming apparatus. In this image forming apparatus, the image forming unit includes each station, the recording material carrier, and a fixing device. The image forming apparatus may also be a so-called one-drum color image forming apparatus in which multiple color toner images are sequentially formed on one image carrier and transferred to the intermediate transfer member or the recording material carried on the recording material carrier. In this image forming apparatus, the image forming unit includes a toner image forming unit (corresponding to a station) that forms a toner image on one image carrier, an intermediate transfer body (or a recording material carrier), and a fixing device. The image forming apparatus may also be a monochrome image forming apparatus. In this case, the image forming unit includes a toner image forming unit (corresponding to a station) that forms a toner image on one image carrier, and a fixing device. [Explanation of symbols]

[0116] 1 Developer recovery device (transport device) 2. Developer recovery transport path 3. Upstream transport section 4. Downstream transport section 5 Drive unit 6L, 6R First and second recovery drive units 7L, 7R 1st and 2nd container sensors 8L, 8R 1st and 2nd full sensors 10L, 10R First and second recovered developer containers (first and second containers) 36 Main discharge pipe (discharge conveying path) 37 Discharge screw (discharge conveying member) 41 Vertical pipe (vertical conveying path) 42 Horizontal pipe (horizontal conveying path) 43 Conveying screw (conveying member) 44L, 44R First and second collection pipes (first and second collection transport paths) 45L, 45R First and second recovery screws (first and second recovery and transport members) 100 Image forming device 150 control section

Claims

1. an image forming unit that forms a toner image; a first container that is detachably provided and that stores residual toner discharged from the image forming unit; a second container that is detachably provided and that stores the residual toner discharged from the image forming unit; a conveying device capable of conveying the residual toner discharged from the image forming unit to the first storage container and the second storage container; a first attachment detection unit that detects attachment of the first storage container; a second attachment detection unit that detects attachment of the second storage container; a first fullness detection unit that detects a full state of the first storage container; a second fullness detection unit that detects a full state of the second storage container; a control unit capable of controlling the conveying device based on detection results of the first attachment detection unit, the second attachment detection unit, the first fullness detection unit, and the second fullness detection unit; and When an image forming operation is being performed in a state in which the remaining toner is being transported to the first storage container by the transport device, if it is detected based on the detection results of the first attachment detection unit and the first fullness detection unit that both the first storage container is not full and that the first storage container has been removed, the control unit controls the transport device to stop transporting the remaining toner to the first storage container and controls the image forming unit to continue the image forming operation, and the control unit, within a predetermined time after detecting the removal of the first storage container, (i) when it is continuously detected based on the detection result of the first attachment detection unit that the first storage container is not attached, controlling the conveying device to continuously stop conveying the remaining toner to the first storage container, and controlling the image forming unit to continue the image forming operation; and (ii) when it is detected based on the detection result of the first attachment detection unit that the first storage container has been attached again, controlling the conveying device to resume conveying the remaining toner to the first storage container, and controlling the image forming unit to continue the image forming operation; An image forming apparatus characterized by executing the above.

2. 2. The image forming apparatus according to claim 1, wherein, based on the detection result of the first mounting detection unit, if it is not detected that the first storage container has been re-mounted before the predetermined time has elapsed after the detection of the removal of the first storage container, the control unit controls the transport device to start transporting the remaining toner to the second storage container, and controls the image forming unit to continue the image forming operation.

3. 2. The image forming apparatus according to claim 1, wherein the predetermined time is longer than the time required to switch the destination of the remaining toner from the first storage container to the second storage container when the control unit detects that the first storage container is full while the remaining toner is being transported to the first storage container during the image forming operation.

4. 2. The image forming apparatus according to claim 1, wherein the predetermined time is between 2 seconds and 5 minutes.

5. 2. The image forming apparatus according to claim 1, wherein the control unit is capable of changing the predetermined time period in accordance with information relating to an amount of toner used to form an image in the image forming operation by the image forming unit.

6. 6. The image forming apparatus according to claim 5, wherein the information is information regarding image density.

7. 2. The image forming apparatus according to claim 1, further comprising: an input unit configured to manually input an instruction; and a setting unit configured to change the predetermined time period based on the instruction.

8. a first mounting portion to which the first storage container can be detachably attached; a second mounting portion to which the second storage container can be detachably attached; a common door for opening and closing the first mounting portion and the second mounting portion, 2. The image forming apparatus according to claim 1, wherein the door is openable and closable during the image forming operation.

Images