Image forming apparatus

Abstract

To shorten downtime when some or all of a plurality of developer storage units storing developer of the same color for each of a plurality of developing colors are replaced.SOLUTION: The developer conveyance device 6 selectively conveys the developer from the plurality of developer containing units 7 attached to the plurality of attachment portion sets 5x to the image forming portion 4 via one of the plurality of relay conveyance paths 62b. The control section 8c determines whether each of the plurality of attachment section sets is an entirely empty set, a partially empty set, or a non-empty set (S1). When the unit replacement operation is detected, the control part 8c sequentially selects a target mounting part set from the all empty set and the partial empty set in the order of giving priority to the all empty set (S8). The control portion 8c causes the developer conveyance device 6 to execute the developer filling process until the filling state of the target relay conveyance path corresponding to the target attachment portion set is detected (S9).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus capable of mounting a plurality of developer containing units each containing a developer of the same color for each of a plurality of developing colors. [Background technology]

[0002] The image forming apparatus capable of color printing includes a plurality of mounting sections to which a plurality of developer accommodating units each accommodating a developer of a plurality of developing colors are attached, and the developer in the plurality of developer accommodating units is supplied to an image forming section.

[0003] Also, an image forming apparatus is known in which two toner containers can be attached, one for each of four colors of toner: yellow, magenta, cyan, and black (see, for example, Patent Document 1). The toner is an example of a developer. The toner container is an example of a developer storage unit.

[0004] If an image forming apparatus has two toner containers, one for each developing color, and one of the toner containers runs out of toner, the printing process can be continued by supplying toner from the other toner container, allowing replacement of the developer accommodating unit without downtime. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-157350 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the image forming apparatus transports the developer from each of the plurality of developer units to the image forming section via each of a plurality of relay transport paths.

[0007] Even after each of the developer units becomes empty, the image forming section can continue the printing process for a while using the developer filled in each of the relay transport paths. That is, each of the relay transport paths functions as a temporary reservoir for the developer.

[0008] However, when all of the developer accommodating units corresponding to a specific relay transport path, which is one of the multiple relay transport paths, become empty, the amount of developer remaining in the specific relay transport path decreases, and in this case, when the developer accommodating unit is replaced, the downtime until the start of the printing process becomes longer.

[0009] An object of the present invention is to provide an image forming apparatus that can reduce downtime when some or all of multiple developer accommodating units that accommodate developers of the same color for each of multiple developing colors are replaced. [Means for solving the problem]

[0010] According to one aspect of the present invention, an image forming apparatus includes a plurality of mounting section sets, an image forming unit, a developer transport device, a first detector, a second detector, a third detector, and a controller. The plurality of mounting section sets are provided corresponding to a plurality of developing colors, and each of the mounting sections has a plurality of developer accommodating units each accommodating a developer of the same color. The image forming unit forms an image using the developer of the plurality of developing colors. The developer transport device has a plurality of relay transport paths corresponding to the plurality of mounting section sets, and selectively transports the developer of each of the plurality of developing colors from the plurality of developer accommodating units attached to the plurality of mounting section sets to the image forming unit via one of the plurality of relay transport paths. The first detector detects a filled state of the developer in each of the plurality of relay transport paths, in which the developer is filled beyond a predetermined amount. The second detector detects an empty state of the developer in each of the plurality of developer accommodating units attached to each of the plurality of mounting section sets. The third detection unit detects a unit replacement operation for some or all of the multiple mounting unit sets. The control unit controls the developer transport device. The control unit determines whether each of the multiple mounting unit sets is a fully empty set in which the empty state of all of the corresponding multiple developer accommodating units is detected, a partially empty set in which the empty state of some of the corresponding multiple developer accommodating units is detected, or a non-empty set in which the empty state of the corresponding multiple developer accommodating units is not detected. When the unit replacement operation is detected, the control unit sequentially selects a target mounting unit set from the fully empty set and the partially empty set in order of giving priority to the fully empty set. Each time the target mounting unit set is selected, the control unit causes the developer transport device to perform a developer filling process to transport the developer from one of the multiple developer accommodating units attached to the target mounting unit set to the image forming unit via the target relay transport path until the filled state of a target relay transport path corresponding to the target mounting unit set is detected among the multiple relay transport paths. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an image forming apparatus that can reduce downtime when some or all of multiple developer accommodating units that accommodate developers of the same color for each of multiple developing colors are replaced. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration of an image forming apparatus according to the first embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a control device in the image forming apparatus according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing a container cover and a toner supply unit inside the container cover in the image forming apparatus according to the first embodiment. [Figure 4] FIG. 4 is a configuration diagram of the toner supply unit in the image forming apparatus according to the first embodiment. [Figure 5] FIG. 5 is a side view of the toner container in the image forming apparatus according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of a procedure for toner supply control in the image forming apparatus according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing the configuration of a toner supply unit in an image forming apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention.

[0014] [First embodiment: configuration of image forming apparatus 10] The image forming apparatus 10 according to the first embodiment is capable of executing a print process for forming an image on a sheet 9.

[0015] 1 is a printer. However, the image forming apparatus 10 may also be a copying machine, a facsimile machine, a multifunction machine, or the like.

[0016] As shown in FIG. 1, the image forming apparatus 10 includes a main housing 1, a sheet storage unit 2, a conveying device 3, an image forming unit 4, a toner supply unit 50, a control device 8, an operation device 801, and a display device 802.

[0017] The main housing 1 is a housing that houses the conveying device 3, the image forming unit 4, the toner supply unit 50, and the control device 8. Inside the main housing 1, a sheet conveying path 300 is also provided.

[0018] The conveying device 3 includes a sheet feeding mechanism 30 and a plurality of pairs of conveying rollers 31. The sheet feeding mechanism 30 sends out the sheets 9 stored in the sheet storage unit 2 to a sheet conveying path 300 one by one.

[0019] The plurality of pairs of conveying rollers 31 convey the sheet 9 along the sheet conveying path 300. One of the plurality of pairs of conveying rollers 31 discharges the sheet 9, on which an image has been formed by the image forming unit 4, from the sheet conveying path 300 onto the discharge tray 1x.

[0020] The image forming unit 4 performs the printing process using toners of a plurality of developing colors. The image forming unit 4 performs the printing process on the sheet 9 conveyed along the sheet conveying path 300.

[0021] The image forming unit 4 is an example of a printing unit that forms an image on the sheet 9. In the example shown in Fig. 1, the image forming unit 4 performs the printing process by an electrophotographic method.

[0022] The electrophotographic image forming unit 4 includes an exposure device 40, one or more unit image forming units 4x, a transfer device 44, and a fixing device 46. The image forming unit 4 shown in Fig. 1 is a tandem color printing apparatus. In this case, the image forming unit 4 includes a plurality of unit image forming units 4x corresponding to a plurality of developing colors.

[0023] In the example shown in FIG. 1, the image forming section 4 includes four unit image forming sections 4x corresponding to the developing colors of yellow, magenta, cyan, and black.

[0024] Each of the unit image forming sections 4x includes a photoconductor 41, a charging device 42, a developing device 43, and a first cleaning device 45. The photoconductor 41 rotates, and the charging device 42 charges the surface of the photoconductor 41.

[0025] The exposure device 40 scans the charged surface of the photoreceptor 41 with laser light to form an electrostatic latent image on the surface of the photoreceptor 41. The development device 43 supplies toner to the surface of the photoreceptor 41 to develop the electrostatic latent image into a toner image.

[0026] The transfer device 44 transfers the toner image on the surface of the photosensitive member 41 onto the sheet 9 being transported along the sheet transport path 300 .

[0027] In the tandem image forming unit 4, the transfer device 44 includes an intermediate transfer belt 441, a plurality of primary transfer devices 442, a secondary transfer device 443, and a second cleaning device 444. The plurality of primary transfer devices 442 are provided corresponding to the plurality of unit image forming units 4x.

[0028] The intermediate transfer belt 441 rotates with a portion thereof aligned with the plurality of unit image forming units 4x. The plurality of primary transfer devices 442 transfer the toner images on the surfaces of the photoconductors 41 of the plurality of unit image forming units 4x onto the surface of the intermediate transfer belt 441. As a result, a color toner image, which is a composite of the toner images of the plurality of colors, is formed on the surface of the intermediate transfer belt 441.

[0029] The secondary transfer device 443 transfers the color toner image on the surface of the intermediate transfer belt 441 to a sheet 9. The fixing device 46 fixes the color toner image on the sheet 9 by applying heat and pressure to the color toner image on the sheet 9.

[0030] The toner supply unit 50 supplies toner to the developing devices 43 of the multiple unit image forming units 4x in the image forming unit 4. The toner supply unit 50 includes multiple mounting units 5. The multiple mounting units 5 are portions to which multiple toner containers 7 are removably mounted.

[0031] The toner supply unit 50 supplies toner in the plurality of toner containers 7 attached to the plurality of attachment units 5 to the developing devices 43 of the plurality of unit image forming units 4x for each development color.

[0032] The sheet 9 is a sheet-like image forming medium such as paper. The toner is an example of a developer. Each toner container 7 is an example of a developer containing unit that contains developer.

[0033] The operation device 801 is a device that accepts operations by a person, and includes, for example, one or both of a touch panel and operation buttons.

[0034] The display device 802 is capable of displaying various types of information. For example, the display device 802 is a panel display device such as a liquid crystal display device. The control device 8 controls various electrical devices included in the image forming apparatus 10.

[0035] As shown in FIG. 2, the control device 8 includes a central processing unit (CPU) 80, a random access memory (RAM) 81, a secondary storage device 82, a signal interface 83, a communication device 84, and the like.

[0036] The CPU 80 executes various control and data processing operations by executing computer programs. The RAM 81 temporarily stores the computer programs executed by the CPU 80 and various data.

[0037] The secondary storage device 82 is a computer-readable non-volatile storage device. The secondary storage device 82 stores the computer programs executed by the CPU 80 and various data. For example, one or both of a flash memory and a hard disk drive may be used as the secondary storage device 82.

[0038] The signal interface 83 converts the detection signals of the various sensors into digital detection data, which is then transmitted to the CPU 80.

[0039] The communication device 84 communicates with a plurality of external devices, including one or more host devices, via a network. The CPU 80 communicates with each of the external devices through the communication device 84. The host device is an information processing device that requests the image forming apparatus 10 to perform the print processing.

[0040] The CPU 80 includes a plurality of processing modules that are realized by executing the computer programs, including a main control unit 8a, a print control unit 8b, and a supply control unit 8c (see FIG. 2).

[0041] The main control unit 8a receives various requests and controls other modules to execute processes according to the requests. For example, the main control unit 8a receives a print request through the operation device 801 or the communication device 84. The main control unit 8a then causes the print control unit 8b to execute processes according to the print request.

[0042] The print control unit 8b controls the conveying device 3 and the image forming unit 4. The print control unit 8b causes the conveying device 3 to convey the sheet 9, while causing the image forming unit 4 to execute the print process.

[0043] The supply control unit 8c controls the toner supply unit 50, thereby controlling the supply of toner from the toner supply unit 50 to the image forming unit 4.

[0044] In this embodiment, the toner supply unit 50 includes a plurality of mounting units 5 to which a plurality of toner containers 7 are attached (see FIGS. 1, 3, and 4). The mounting units 5 are divided into a plurality of mounting unit sets 5x provided corresponding to a plurality of developing colors (see FIGS. 3 and 4).

[0045] Each of the multiple mounting portion sets 5x has multiple mounting portions 5 to which multiple toner containers 7 containing toner of the same color are attached. In this embodiment, the multiple mounting portion sets 5x are four mounting portion sets 5x corresponding to four developing colors: yellow, magenta, cyan, and black (see FIGS. 3 and 4).

[0046] In this embodiment, each of the four mounting portion sets 5x has two mounting portions 5 to which two toner containers 7 containing toner of the same color are attached (see FIGS. 3 and 4).

[0047] The main housing 1 has an opening 1a that forms an access path to the four mounting portion sets 5x from outside the main housing 1 (see FIG. 3). The image forming apparatus 10 has a container cover 5a that can open and close the opening 1a (see FIG. 3).

[0048] With the container cover 5a open, it is possible to remove and install some or all of the eight toner containers 7 attached to the four attachment portion sets 5x. In other words, with the container cover 5a open, it is possible to replace some or all of the eight toner containers 7 attached to the four attachment portion sets 5x.

[0049] Since the toner supply unit 50 has two mounting portions 5 for each developing color, when one of the two toner containers 7 for each developing color runs out of toner, the printing process can be carried out by supplying toner from the other toner container. This makes it possible to replace an empty toner container 7 without downtime.

[0050] The toner supply unit 50 transports the toner from each of the plurality of toner containers 7 to each of the developing devices 43 of the image forming unit 4 via each of the plurality of relay transport paths 6b.

[0051] Even after each toner container 7 becomes empty, the image forming unit 4 can continue the printing process for a while using the toner stored in each relay transport path 6b. In other words, each relay transport path 6b functions as a temporary toner storage tank.

[0052] However, if both of the toner containers 7 corresponding to a specific relay transport path, which is one of the multiple relay transport paths 6b, become empty, the amount of toner remaining in the specific relay transport path decreases. In this case, when the empty toner container 7 is replaced, the downtime until the start of the printing process becomes longer.

[0053] The image forming apparatus 10 has a feature for reducing downtime when one or both of two toner containers 7, each containing toner of the same color for each of a plurality of developing colors, is replaced.

[0054] [Configuration of toner supply unit 50] As described above, the toner supply unit 50 includes four toner attachment sets 5x (see 4) corresponding to the four developing colors. The four toner attachment sets 5x correspond to yellow, magenta, cyan, and black toner, respectively. Yellow, magenta, cyan, and black are examples of developing colors.

[0055] Each of the four mounting portion sets 5x includes two mounting portions 5. Therefore, the toner supply unit 50 includes eight mounting portions 5. In each of the four mounting portion sets 5x, two toner containers 7 containing toner of the same color are mounted in the two mounting portions 5.

[0056] In the example shown in FIG. 4, each of the two toner containers 7 that contain black toner has a larger toner capacity than each of the other six toner containers 7.

[0057] The toner supply unit 50 further includes a toner transport device 6 (see FIG. 4). The toner transport device 6 selectively transports toner of each of the four developing colors from eight toner containers 7 attached to the four attachment unit sets 5x to the image forming unit 4.

[0058] The toner transport device 6 includes eight individual transport paths 6a corresponding to the eight mounting portions 5, and four relay transport paths 6b corresponding to the four mounting portion sets 5x.

[0059] Each individual transport path 6a is a toner transport path that communicates with the toner discharge port 7a of each toner container 7. In this embodiment, each individual transport path 6a is arranged in the vertical direction. The toner in each toner container 7 is sent into each individual transport path 6a through the toner discharge port 7a.

[0060] Furthermore, the toner transport device 6 includes a toner sending device 61 and an intermediary transport device 62. The toner sending device 61 sends the toner contained in one selected from the eight toner containers 7 attached to the eight attachment units 5 to a corresponding one of the eight individual transport paths 6a.

[0061] In this embodiment, each toner container 7 has a spiral portion 7b that protrudes spirally from the inside of the bottle-shaped body (see FIG. 5). As a result, the toner contained in each toner container 7 is sent to each individual transport path 6a through the toner discharge port 7a as each toner container 7 rotates.

[0062] The toner delivery device 61 includes a delivery motor 61a and a first transmission mechanism 61b that transmits the rotational force of the delivery motor 61a to one selected from the eight toner containers 7. In other words, the first transmission mechanism 61b selectively transmits the rotational force of the delivery motor 61a to one of the eight toner containers 7 attached to the eight attachment portions 5.

[0063] Each toner container 7 is rotated by receiving the rotational force of the delivery motor 61a through the first transmission mechanism 61b. The toner delivery device 61 selectively rotates one of the eight toner containers 7, thereby delivering the toner from one of the eight toner containers 7 to a corresponding one of the eight individual transport paths 6a.

[0064] Each of the relay transport paths 6b includes a horizontal relay transport path 6ba and a vertical relay transport path 6bb, that is, the toner transport device 6 includes four horizontal relay transport paths 6ba and four vertical relay transport paths 6bb.

[0065] The four horizontal relay transport paths 6ba are connected to two of the eight individual transport paths 6a, respectively. The four vertical relay transport paths 6bb are connected to the four horizontal relay transport paths 6ba and the four developing devices 43, respectively.

[0066] The toner sent out from each toner container 7 passes through the inside of each individual transport path 6a and falls into each corresponding lateral relay transport path 6ba.

[0067] The relay conveying device 62 conveys the toner in each of the horizontal relay conveying paths 6ba into each of the vertical relay conveying paths 6bb. The toner conveyed by the relay conveying device 62 falls inside each of the vertical relay conveying paths 6bb and is supplied to each of the developing devices 43.

[0068] The relay conveying device 62 includes a conveying motor 62a, a plurality of conveying screws 62c arranged in each of the plurality of horizontal relay conveying paths 6ba, and a second transmission mechanism 62b that transmits the rotational force of the conveying motor 62a to each of the conveying screws 62c.

[0069] The second transmission mechanism 62b selectively transmits the rotational force of the transport motor 62a to one of the plurality of transport screws 62c.

[0070] As described above, the toner conveying device 6 selectively conveys toner of each of the four developing colors from the eight toner containers 7 mounted in the four mounting unit sets 5x to the image forming unit 4 via one of the four relay conveying paths 6b.

[0071] The toner transport device 6 includes four relay path toner sensors 60 for detecting a filling state in which the toner in each of the four relay transport paths 6b exceeds a predetermined amount.

[0072] In this embodiment, each relay path toner sensor 60 detects the toner present inside the upper end of each vertical relay transport path 6bb. In each relay transport path 6b, the filled state is a state in which toner has filled up to the level of each relay path toner sensor 60 inside each vertical relay transport path 6bb. The four relay path toner sensors 60 are an example of a first detection unit that detects the filled state.

[0073] For example, each of the relay path toner sensors 60 is a magnetic permeability sensor or a transmission type photosensor.

[0074] The magnetic permeability sensor detects the magnetic permeability, which changes depending on the amount of toner inside each of the vertical relay transport paths 6bb. The state where the detected value of the magnetic permeability sensor is within a predetermined reference range is the filled state.

[0075] The transmission type photosensor emits light from one to the other of a pair of transparent windows formed on each of the vertical relay conveyance paths 6bb, and detects the amount of light that has passed through the pair of windows. The state in which the amount of light detected by the transmission type photosensor is below a lower limit amount is the filled state.

[0076] [Toner supply control] Next, an example of a procedure for toner supply control, which is a process for controlling the toner supply unit 50, will be described with reference to the flowchart shown in FIG.

[0077] The supply control unit 8c starts the toner supply control when the printing process is started.

[0078] In the following description, S1, S2, ... represent identification symbols of a plurality of steps in the toner supply control. In the toner supply control, the process of step S1 is executed first.

[0079] <Process S1> In step S1, the supply control unit 8c executes a unit state detection process, which includes an empty detection process and a mounting unit set state determination process.

[0080] The unit state detection process is a process for detecting whether each of the two toner containers 7 attached to each of the two attachment portions 5 in each of the multiple attachment portion sets 5x is empty of toner. In this embodiment, the supply control unit 8c detects the empty state based on the operating state of the toner transport device 6 and the detection results of each of the four relay path toner sensors 60.

[0081] Here, one selected from the eight toner containers 7 mounted in the eight mounting units 5 is referred to as the target toner container. Also, one of the four relay transport paths 6b corresponding to the target toner container is referred to as the target relay transport path. Similarly, one of the four mounting unit sets 5x corresponding to the target toner container is referred to as the target mounting unit set.

[0082] In addition, the process in which the toner transport device 6 transports the toner in the target toner container to the image forming unit 4 via the target relay transport path until the filling state of the target relay transport path is detected is called the toner filling process.

[0083] The supply control unit 8c detects the empty state of the target toner container when the filled state of the target relay transport path is not detected until the time that the toner transport device 6 continues to perform the toner filling process reaches an upper limit time.

[0084] That is, the supply control unit 8c detects the empty state of each toner container 7 based on the operating state of the toner transport device 6 and the detection result of the filling state by each of the relay path toner sensors 60. The supply control unit 8c that executes the empty detection process is an example of a second detection unit.

[0085] The mounting portion set state determination process is a process for determining whether each of the four mounting portion sets 5x is a fully empty set, a partially empty set, or a non-empty set.

[0086] The supply control unit 8c determines that the set to be judged is the all-empty set when the empty state of both of the two toner containers 7 corresponding to the set to be judged out of the four mounting unit sets 5x is detected.

[0087] Furthermore, when the empty state of only one of the two toner containers 7 corresponding to the determination target set is detected, the supply control unit 8c determines that the determination target set is the partially empty set.

[0088] Furthermore, when the empty state of the two toner containers 7 corresponding to the determination target set is not detected, the supply control unit 8c determines that the determination target set is the non-empty set.

[0089] The supply control unit 8c executes the process of step S2 when the all-empty set does not exist, and executes the process of step S5 when the all-empty set does exist.

[0090] <Process S2> In step S2, the supply control unit 8c executes a unit replacement operation detection process, which is a process for detecting a unit replacement operation for some or all of the four mounting portion sets 5x.

[0091] In this embodiment, the image forming apparatus 10 includes a cover detection sensor 5b that detects whether the container cover 5a is closed (see FIG. 3).

[0092] The supply control unit 8c detects, as the unit replacement operation, that the cover detection sensor 5b has changed from a state in which it does not detect the closed state of the container cover 5a to a state in which it detects the closed state. The cover detection sensor 5b and the supply control unit 8c that executes the processing of step S2 are an example of a third detection unit that detects the unit replacement operation.

[0093] The supply control unit 8c executes the process of step S3 when the unit replacement operation is not detected, whereas the supply control unit 8c executes the process of step S8 when the unit replacement operation is detected.

[0094] <Process S3> In step S3, the supply control unit 8c determines whether or not a predetermined filling start condition is met for each of the four developing colors.

[0095] For example, the refill start condition includes one or both of a non-refill condition and a pixel count condition. The non-refill condition is a condition that any of the four relay path toner sensors 60 does not detect the refill state. The pixel count condition is a condition that the cumulative value of the number of pixels drawn for each developing color in the printing process exceeds a predetermined reference pixel number.

[0096] If the supply control unit 8c determines that the filling start condition is not met, it repeats the processes from step S1 onwards. On the other hand, if the supply control unit 8c determines that the filling start condition is met, it executes the process of step S4.

[0097] <Process S4> In step S4, the supply control unit 8c selects the target relay conveying path from the four relay conveying paths 6b corresponding to the color for which the filling start condition is met, and selects the target toner container from the eight toner containers 7 corresponding to the target relay conveying path.

[0098] Furthermore, in step S4, the supply control unit 8c causes the toner transport device 6 to execute the toner filling process for the target toner container and the target relay transport path. As described above, the toner filling process is a process of transporting toner from the target toner container to the image forming unit 4 via the target relay transport path until the filling state of the target relay transport path is detected.

[0099] For example, each time the empty state of one of the two toner containers 7 in each mounting portion set 5x is detected, the supply control portion 8c selects the other of the two toner containers 7 as the supply source container.

[0100] In step S4, the supply control unit 8c selects the supply source container corresponding to the target relay transport route as the target container.

[0101] In addition, if the empty state of the target toner container is detected while the toner filling process is being performed, the supply control unit 8c switches the selection of the target toner container and then causes the toner conveying device 6 to perform the toner filling process.

[0102] After executing the process of step S4, the supply control unit 8c repeats the processes from step S1 onwards.

[0103] In addition, when the toner filling process of step S4 is being executed, if the target mounting unit set corresponding to the target relay transport path changes from the partially empty set to the fully empty set, the supply control unit 8c executes the process of step S5 (not shown).

[0104] <Process S5> In step S5, the supply control unit 8c prohibits the print process by the image forming unit 4. As a result, if the print process is already being executed, the print control unit 8b stops the print process by the image forming unit 4. Furthermore, execution of a new print process is prohibited until the prohibition of the print process is lifted.

[0105] After executing the process of step S5, the supply control unit 8c executes the process of step S6.

[0106] <Process S6> In step S6, the supply control unit 8c outputs an alarm indicating that the printing process is prohibited due to the occurrence of the all-empty set. The supply control unit 8c outputs the alarm via one or both of the display device 802 and the communication device 84.

[0107] After executing the process of step S6, the supply control unit 8c executes the process of step S7.

[0108] <Process S7> In step S7, the supply control unit 8c executes the unit replacement operation detection process in the same manner as in step S2. The supply control unit 8c repeats the process of step S7 until the unit replacement operation is detected.

[0109] The supply control unit 8c executes the process of step S8 when it detects the unit replacement operation.

[0110] <Process S8> In step S8, the supply control unit 8c selects one target mounting unit set from the all-empty set and the partially-empty set determined in step S2 or step S4. If the all-empty set exists, the supply control unit 8c selects the target mounting unit set by giving priority to the all-empty set.

[0111] Furthermore, the supply control unit 8c selects the supply source unit corresponding to the selected target mounting unit set as a target unit. After executing the process of step S8, the supply control unit 8c executes the process of step S9.

[0112] <Process S9> In step S9, the supply control unit 8c causes the toner conveying device 6 to execute the toner filling process corresponding to the target mounting portion set and the target unit selected in step S9. The toner filling process is the same process as the process in step S4.

[0113] In addition, if the empty state of the target toner container is detected while the toner filling process is being performed, the supply control unit 8c switches the selection of the target toner container and then causes the toner conveying device 6 to perform the toner filling process.

[0114] After executing the process of step S9, the supply control unit 8c executes the process of step S10.

[0115] In addition, when the toner filling process of step S9 is being performed, if the target mounting portion set changes from the partially empty set to the fully empty set, the supply control unit 8c executes the process of step S5 (not shown).

[0116] <Process S10> In step S10, if the supply control unit 8c has not detected the filled state for one or more of the four relay conveyance paths 6b, the supply control unit 8c repeats the processing from step S8 onwards.

[0117] On the other hand, if the filling state of all four relay conveyance paths 6b has been detected, the supply control unit 8c executes the process of step S11.

[0118] <Process S11> In step S11, the supply control unit 8c releases the prohibition of the printing process. After executing the process of step S11, the supply control unit 8c repeats the processes from step S1 onwards until the printing process is completed.

[0119] As described above, the supply control unit 8c determines whether each of the four mounting portion sets 5x is the fully empty set, the partially empty set, or the non-empty set (step S1).

[0120] Furthermore, when the unit replacement operation is detected, the supply control unit 8c sequentially selects the target mounting unit set from the fully empty set and the partially empty set in order of giving priority to the fully empty set (step S8).

[0121] Furthermore, each time the target mounting unit set is selected, the supply control unit 8c causes the toner conveying device 6 to execute the toner filling process until the filling state of the target relay conveying path corresponding to the target mounting unit set among the four relay conveying paths 6b is detected (step S9).

[0122] As described above, the toner filling process is a process of transporting toner from one of the two toner containers 7 attached to the target attachment set to the image forming unit 4 via the target relay transport path.

[0123] When the unit replacement operation is detected, if the target mounting part set is selected from the four mounting part sets 5x in a predetermined order, the toner filling process corresponding to the all-empty set may be postponed. If the toner filling process corresponding to the all-empty set is postponed, the resumption of the printing process may be delayed, which may result in a long downtime.

[0124] On the other hand, by adopting the image forming apparatus 10, the fully empty set is selected as the target mounting unit set in preference to the partially empty set, thereby reducing downtime when some or all of the multiple toner containers 7 are replaced.

[0125] [Second embodiment] Next, an image forming apparatus 10A according to a second embodiment will be described with reference to FIG.

[0126] In FIG. 7, the same components as those shown in FIGS. 3 and 4 are designated by the same reference numerals.

[0127] Image forming apparatus 10A has a configuration in which toner supply unit 50 of image forming apparatus 10 is replaced with toner supply unit 50A. Toner supply unit 50A has a configuration in which a plurality of remaining toner sensors 5c are added to toner supply unit 50.

[0128] In this embodiment, eight remaining toner amount sensors 5c are provided in eight mounting portions 5.

[0129] The eight toner remaining amount sensors 5c detect the empty state of each of the two toner containers 7 attached to each of the two attachment portions 5 in each of the four attachment portion sets 5x. The eight toner remaining amount sensors 5c are an example of a second detection portion that detects the empty state of each of the toner containers 7.

[0130] For example, each of the remaining toner amount sensors 5c is a magnetic permeability sensor or a transmission type photosensor.

[0131] The magnetic permeability sensor detects the magnetic permeability that changes depending on the amount of toner inside each toner container 7. The empty state occurs when the detected value of the magnetic permeability sensor is outside a predetermined reference range.

[0132] The transmission photosensor emits light from one side to the other of a transparent annular window formed around the entire circumference of each toner container 7, and detects the amount of light that passes through the annular window. The empty state is indicated when the amount of light detected by the transmission photosensor exceeds an upper limit.

[0133] In the toner supply control step S1, the supply control unit 8c executes the unit state detection process based on the detection results of the eight remaining toner sensors 5c. This is what makes the image forming apparatus 10A different from the image forming apparatus 10.

[0134] When the image forming apparatus 10A is employed, the same effects as when the image forming apparatus 10 is employed can be obtained.

[0135] [Variations] In the image forming apparatus 10, 10A, each of the four mounting portion sets 5x may include three or more mounting portions 5. Also, in the image forming apparatus 10, 10A, the number of the mounting portion sets 5x in the toner supply unit 50 may be two, three, five or more depending on the number of developing colors.

[0136] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0137] <Appendix 1> a plurality of mounting portion sets each having a plurality of mounting portions to which a plurality of developer accommodating units accommodating developers of the same color are attached, the mounting portions being provided corresponding to a plurality of developing colors; an image forming unit that forms an image using the developers of the plurality of development colors; a developer transport device having a plurality of relay transport paths corresponding to the plurality of mounting portion sets, and selectively transporting the developer of each of the plurality of developing colors from the plurality of developer accommodating units mounted in the plurality of mounting portion sets to the image forming unit via any of the plurality of relay transport paths; a first detection unit that detects a filling state in which the developer is filled in excess of a predetermined amount for each of the plurality of relay transport paths; a second detection section that detects an empty state of the developer in each of the developer accommodating units that are attached to the attachment portions in each of the attachment portion sets; a third detection unit that detects a unit replacement operation for some or all of the plurality of mounting unit sets; a control unit that controls the developer transport device, the control unit determines whether each of the plurality of mounting portion sets is a fully empty set in which the empty states of all of the corresponding plurality of developer accommodating units are detected, a partially empty set in which the empty states of some of the corresponding plurality of developer accommodating units are detected, or a non-empty set in which the empty states of the corresponding plurality of developer accommodating units are not detected, When the unit replacement operation is detected, the control unit sequentially selects a target mounting unit set from the all-empty set and the partially-empty set in an order in which the all-empty set is given priority; The control unit of the image forming device causes the developer transport device to execute a developer filling process each time the target mounting part set is selected, in which the developer is transported from one of the plurality of developer storage units mounted on the target mounting part set to the image forming part via the target relay transport path until the filling state of the target relay transport path among the plurality of relay transport paths corresponding to the target mounting part set is detected.

[0138] <Appendix 2> 2. The image forming apparatus according to claim 1, wherein the second detection unit detects the empty state based on an operating state of the developer transport device and a detection result of the first detection unit.

[0139] <Appendix 3> the plurality of mounting portion sets are four mounting portion sets corresponding to four developing colors of cyan, magenta, yellow, and black, The image forming apparatus according to claim 1 or 2, wherein the plurality of mounting portions in each of the four mounting portion sets are two mounting portions into which two developer accommodating units are mounted. [Explanation of symbols]

[0140] 1: Main housing 1a:Aperture 3:Transportation device 4: Image forming unit 4x: Unit image forming unit 5: Mounting part 5a: Container cover 5b: Cover detection sensor 5c: Toner level sensor 5x: Mounting part set 6: Toner transport device 6a: Individual transport path 6b: Relay transport route 7: Toner container 8: Control device 10: Image forming device 10A: Image forming device 50: Toner supply unit 50A: Toner supply unit 60: Toner sensor for relay path 61: Toner delivery device 61a: Sending motor 61b: First transmission mechanism 62: Relay transport device 62a: Transport motor 62b: Second transmission mechanism 62c: Conveying screw

Claims

1. a plurality of mounting portion sets each having a plurality of mounting portions to which a plurality of developer accommodating units accommodating developers of the same color are attached, the mounting portions being provided corresponding to a plurality of developing colors; an image forming unit that forms an image using the developers of the plurality of development colors; a developer transport device having a plurality of relay transport paths corresponding to the plurality of mounting portion sets, and selectively transporting the developer of each of the plurality of developing colors from the plurality of developer accommodating units mounted in the plurality of mounting portion sets to the image forming unit via any of the plurality of relay transport paths; a first detection unit that detects a filling state in which the developer is filled in excess of a predetermined amount for each of the plurality of relay transport paths; a second detection section configured to detect an empty state of the developer in each of the developer accommodating units attached to the attachment sections in each of the attachment section sets; a third detection unit that detects a unit replacement operation for some or all of the plurality of mounting unit sets; a control unit that controls the developer transport device, the control unit determines whether each of the plurality of mounting portion sets is a fully empty set in which the empty states of all of the corresponding plurality of developer accommodating units are detected, a partially empty set in which the empty states of some of the corresponding plurality of developer accommodating units are detected, or a non-empty set in which the empty states of the corresponding plurality of developer accommodating units are not detected, When the unit replacement operation is detected, the control unit sequentially selects a target mounting unit set from the all-empty set and the partially-empty set in an order in which the all-empty set is given priority; The control unit of the image forming device causes the developer transport device to execute a developer filling process each time the target mounting part set is selected, in which the developer is transported from one of the plurality of developer storage units mounted on the target mounting part set to the image forming part via the target relay transport path until the filling state of the target relay transport path among the plurality of relay transport paths corresponding to the target mounting part set is detected.

2. 2. The image forming apparatus according to claim 1, wherein the second detection unit detects the empty state based on an operating state of the developer transport device and a detection result of the first detection unit.

3. the plurality of mounting portion sets are four mounting portion sets corresponding to four developing colors of cyan, magenta, yellow, and black, 3. The image forming apparatus according to claim 1, wherein the plurality of mounting portions included in each of the four mounting portion sets are two mounting portions to which two developer accommodating units are attached.

Images