Image forming apparatus and method for preventing toner adhesion

Abstract

To provide an image forming apparatus that forms an image by using toner, and to simplify a configuration to prevent adherence of the toner.SOLUTION: An image forming apparatus comprises: a toner conveyance path 83S that is arranged between a toner container 72 and a toner image forming unit 42; a conveying screw 85 that is rotated by a toner conveying motor 86 and conveys toner G along the toner conveyance path 83S; and a control unit that controls the toner conveying motor 86. The conveying screw 85, when rotated in a normal direction PR, conveys the toner G to the downstream side, and when rotated in a reverse direction NR, conveys the toner G to the upstream side. The control unit drives the toner conveying motor 86 to switch a rotation direction of the conveying screw 85 to the normal direction PR or the reverse direction NR, thereby executing an adherence prevention operation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a method for preventing toner adhesion therein. [Background technology]

[0002] In image forming devices employing electrophotography, such as printers and copiers, images are formed on recording media using toner. If toner is left unused for a long period of time, the toner may adhere to the toner transport path. Since this adhesion of toner to the transport path impairs smooth toner transport, a configuration for preventing toner from adhering to the transport path is known. For example, Patent Document 1 describes an image forming device in which a temperature sensor is installed near an image forming unit, and when the temperature detected by the temperature sensor is above a specified temperature, an agitating member is rotated inside the toner cartridge to agitate the toner. Summary of the Invention [Problem to be solved by the invention]

[0003] However, the image forming apparatus described in Patent Document 1 has a problem in that the configuration becomes complicated because a dedicated stirring member is provided inside the toner cartridge. The present invention has been made in view of the above circumstances, and has as its object to simplify the configuration for preventing toner from adhering. [Means for solving the problem]

[0004] In order to solve the above problem, the invention of claim 1 comprises a toner transport path disposed between a toner storage means and a developing means, and a toner transport path rotated by a drive motor and moving along the toner transport path. Tetoa conveying member for conveying the toner, and a control means for controlling the drive motor, wherein the conveying member conveys the toner toward the developing means when rotated in a forward direction, and conveys the toner toward the toner storage means when rotated in a reverse direction, and the control means drives the drive motor to switch the rotation direction of the conveying member between the forward direction and the reverse direction, thereby performing a sticking prevention operation. a first control means for driving the drive motor during a period when a first operation mode is set and not driving the drive motor during a period when a second operation mode is set, the second operation mode having lower power consumption than the first operation mode; and a second control means for determining whether or not to execute the sticking prevention operation during the period when the second operation mode is set and for causing the first control means to drive the drive motor when it is determined that the sticking prevention operation should be executed. The image forming apparatus is characterized by the above. [Effects of the Invention]

[0005] According to the present invention, the structure for preventing toner adhesion can be simplified. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram showing the overall configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 3 is a schematic diagram showing the configuration of a toner supply unit. [Figure 3] FIG. 2 is a cross-sectional view illustrating the configuration of a toner image forming unit. [Figure 4] FIG. 2 is a diagram illustrating a hardware configuration of the image forming apparatus. [Figure 5] FIG. 2 is a functional block diagram of a control unit. [Figure 6] 5 is a schematic diagram illustrating the supply of toner discharged from a toner container to a toner image forming unit. [Figure 7] 10 is a schematic diagram illustrating a state in which toner begins to adhere to the toner transport path. [Figure 8] 10 is a schematic diagram illustrating a state in which toner aggregation has progressed in a toner transport path. [Figure 9] 10 is a schematic diagram illustrating a state at the start of the anti-sticking operation. [Figure 10] 10 is a schematic diagram illustrating a state in which toner is transported to the toner image forming unit during the sticking prevention operation. [Figure 11] 10 is a schematic diagram illustrating a state in which toner is transported to the toner container side during the adhesion prevention operation. [Figure 12] 10 is a flowchart of a process for preventing sticking in a normal mode. [Figure 13] 10 is a flowchart of a process for setting an execution interval of a sticking prevention operation in a power saving mode. [Figure 14] 10 is a flowchart of a process for preventing sticking performed by a system control unit. [Figure 15] 4 is a flowchart of a process for preventing sticking performed by an engine control unit. [Figure 16] 10 is a flowchart of a transfer path cooling process performed by a system control unit. [Figure 17] 10 is a flowchart of a transfer path cooling process performed by an engine control unit. DETAILED DESCRIPTION OF THE INVENTION

[0007] <Outline of image forming apparatus 1> The present invention will be described in detail with reference to the embodiments shown in the drawings. First, an outline of the image forming apparatus 1 will be described. However, unless otherwise specified, the components, types, combinations, shapes, relative arrangements, etc. described in this embodiment are merely illustrative examples and do not limit the scope of the present invention. FIG. 1 is a schematic diagram showing the overall configuration of an image forming apparatus 1 according to one embodiment of the present invention, and FIG. 2 is a schematic diagram showing the configuration of a toner supply unit 80. As shown in FIG.

[0008] The image forming apparatus 1 shown in FIG. 1 includes an image forming unit 40 that forms an image on the surface of a recording medium such as paper P. As shown in FIG. 2, the image forming unit 40 includes a toner transport path 83S between a toner container 72 (toner storage means) and a toner image forming unit 42 (developing means). The toner transport path 83S is provided with a transport screw 85 (transport member) that is rotated about its axis by a toner transport motor 86 (drive motor) and transports toner along the toner transport path 83S. The transport screw 85 is also used to supply toner in the toner transport path 83S to the toner image forming unit 42. When the transport screw 85 is rotated in a forward direction PR, the toner is transported downstream (toward the toner image forming unit 42) as indicated by an arrow FF, and when the transport screw 85 is rotated in a reverse direction NR, the toner is transported upstream (toward the toner container 72) as indicated by an arrow BC. The operation of the toner conveying motor 86 is controlled by a control unit 100 (control means) shown in Fig. 4. When it is determined that the toner adhesion prevention operation should be performed, the control unit 100 drives the toner conveying motor 86 and performs the adhesion prevention operation by switching the rotation direction of the conveying screw 85 between the forward direction PR and the reverse direction NR.

[0009] The toner in the toner transport path 83S is transported downstream when the transport screw 85 rotates in the forward direction PR, and is transported upstream when the transport screw 85 rotates in the reverse direction NR. Therefore, the toner transport direction is switched in accordance with the change in the rotation direction of the transport screw 85. By switching the toner transport direction, toner aggregation is suppressed, and the toner is prevented from adhering to the toner transport path 83S. In this image forming apparatus 1, the toner adhesion prevention operation is performed by the conveying screw 85 for supplying the toner in the toner conveying path 83S to the toner image forming unit 42, thereby simplifying the configuration for preventing toner adhesion.

[0010] <Details of Image Forming Apparatus 1> Next, a detailed description will be given of the image forming apparatus 1. As illustrated in Fig. 1, the image forming apparatus 1 includes a scanner unit 10 that reads an original placed on an original table 11 using a reading mechanism 12 and generates image data, a paper feed unit 20 that stores stacks of paper P (sheet-like recording media) on which images are to be formed and separates and supplies the stored paper P one by one, a paper transport unit 30 that transports the paper P supplied from the paper feed unit 20, an image forming unit 40 that forms an image based on image data on the paper P transported by the paper transport unit 30, a temperature sensor 51 (temperature measuring means, environmental information detecting means) that detects the temperature inside the apparatus, a humidity sensor 52 (humidity measuring means, environmental information detecting means) that detects the humidity inside the apparatus, a cooling fan 53 (cooling means, see Fig. 2) that introduces outside air into the apparatus to lower the temperature inside the apparatus (particularly the temperature of the toner transport path 83S), and an operation unit 60 that displays various information and accepts operations by a user.

[0011] 4, the operation unit 60 includes a display unit 61 that displays various types of information and an input unit 62 that accepts input operations by the user. The display unit 61 is, for example, a liquid crystal panel, and the input unit 62 is, for example, a touch panel or operation buttons.

[0012] The paper feed section 20 is housed in the lower part of the device and includes a paper feed cassette 21 that stores multiple sheets of paper P in a stacked state (paper stack state), and a paper feed roller 22 that is driven by a paper feed motor and feeds out the topmost sheet of paper P one by one from the paper stack. The paper transport section 30 includes transport rollers 31 arranged at intervals on the transport path of the paper P and driven by a transport motor, discharge rollers 32A, 32B, 32C arranged at the end of the transport path FP of the paper P and driven by a discharge motor, and stack sections 33A, 33B, 33C in which the paper P discharged outside the transport path FP by the discharge rollers 32A, 32B, 32C is held in a stacked state.

[0013] The image forming unit 40 includes a toner container storage section 41 that detachably stores the toner container 72, a toner image forming section 42 that forms a toner image, an exposure section 43 that irradiates the photosensitive drum 91 of the toner image forming section 42 with laser light L to form an electrostatic latent image, as shown in Figure 3, an intermediate transfer belt 44 that transfers the toner image formed by the toner image forming section 42 onto paper P transported by the paper transport section 30, and a fixing section 45 that fixes the toner image transferred onto the paper P.

[0014] As illustrated in FIG. 2, the toner container 72 has a cylindrical container body 72a with one end open and the other end closed, and a toner discharge outlet 72b provided at the open end (one end) of the container body 72a, and is provided for each color of toner, as illustrated in FIG. In this embodiment, toner container 72Y containing yellow (Y) toner, toner container 72C containing cyan (C) toner, toner container 72M containing magenta (M) toner, and toner container 72K containing black toner are provided. Therefore, toner container holder 41 holds each of toner containers 72Y, 72M, 72C, and 72K individually and detachably. In addition, toner container holder 41 is configured to hold each of toner containers 72Y, 72M, 72C, and 72K rotatably about its axis (rotatably in the direction of arrow R). Between each of the toner containers 72Y, 72M, 72C, and 72K and the toner image forming unit 42, a toner supply unit 80 (80Y, 80M, 80C, and 80K) is provided to supply the toner stored in each of the toner containers 72Y, 72M, 72C, and 72K to the storage unit and the toner image forming unit 42. The toner supply unit 80 will be described later.

[0015] A toner image forming unit 42 is provided for each color of toner. In this embodiment, toner image forming unit 42Y that forms a yellow (Y) toner image, toner image forming unit 42C that forms a cyan (C) toner image, toner image forming unit 42M that forms a magenta (M) toner image, and toner image forming unit 42K that forms a black toner image are provided. Note that, since the toner image forming units 42Y, 42M, 42C, and 42K have a common configuration, they will be collectively described as toner image forming unit 42. Fig. 3 is a cross-sectional view illustrating the configuration of toner image forming unit 42. As shown in Fig. 3, toner image forming unit 42 includes a photosensitive drum 91 that carries an electrostatic latent image, a charger 92 that uniformly charges the surface of photosensitive drum 91, a developing unit 93 that forms a toner image by causing toner supplied from toner supply unit 80 to adhere to the electrostatic latent image formed on the surface of photosensitive drum 91, and a cleaning unit 94 that collects untransferred toner remaining on photosensitive drum 91.

[0016] The photosensitive drum 91 has an image carrier 91b formed on the outer peripheral surface of a cylindrical drum main body 91a, and rotates around its axis (in the direction of arrow 91R in FIG. 3). The charger 92 is provided on the outer surface of the photosensitive drum 91, and is located before the irradiation position of the laser light L from the exposure unit 43 in the rotation direction. Therefore, the laser light L is irradiated onto the surface of the image carrier 91b that has been uniformly charged by the charger 92. By irradiating the laser light L, an electrostatic latent image is formed on the outer surface of the photosensitive drum 91 (image carrier 91b).

[0017] The developing unit 93 includes a developing roller 93a facing the photosensitive drum 91, a doctor blade 93b facing the developing roller 93a, toner storage sections 93c and 93d, and two conveying screws 93e disposed inside the toner storage sections 93c and 93d. The developing roller 93a is composed of a magnet fixed inside, a sleeve that rotates around the magnet, and the like.

[0018] The toner storage section 93c, located upstream, has an upper opening that communicates with the drop path forming section 84 of the toner supply section 80. Therefore, toner G supplied from the toner supply section 80 is temporarily stored in the toner storage section 93c and then transported by the transport screw 93e to the toner storage section 93d, located downstream. The toner transported to the toner storage section 93d is carried on the surface of the developing roller 93a. The doctor blade 93b scrapes off excess toner G, thereby allowing an appropriate amount of toner G to be carried on the surface of the developing roller 93a. The toner G carried on the surface of the developing roller 93a is transferred to the photosensitive drum 91 on which the electrostatic latent image is formed. A toner image is formed on the outer surface of the photosensitive drum 91 by the transferred toner.

[0019] A primary transfer bias roller 46 is disposed on the outer surface of the photosensitive drum 91, further inward in the rotation direction than the developing roller 93a, with the intermediate transfer belt 44 sandwiched therebetween. When the toner image formed on the outer surface of the photosensitive drum 91 reaches the intermediate transfer belt 44, it is primarily transferred onto the surface of the intermediate transfer belt 44 at the position of the primary transfer bias roller 46. 1, the toner image that has been primarily transferred onto intermediate transfer belt 44 is transferred onto paper P at the position of secondary transfer roller pair 47. Paper P onto which the toner image has been transferred is transported to fixing unit 45, where heat and pressure are applied by a fixing belt and a pressure roller that fixing unit 45 includes. As a result, the toner image is fixed onto paper P to become a color image. The paper P on which the color image is formed moves along the transport path FP, and is discharged to the stacking units 33A, 33B, and 33C, where it is stacked in order.

[0020] <Details of the Toner Supply Unit 80> As shown in FIG. 2, the toner supply unit 80 includes a guide path forming unit 81 that forms a guide path 81S that is connected to the discharge outlet 72b of the toner container 72, a sub-hopper 82 that is connected to the downstream end of the guide path forming unit 81, a cylindrical transport path forming unit 83 that is connected to the sub-hopper 82 and forms a toner transport path 83S, a cylindrical drop path forming unit 84 that is formed continuously from the downstream end of the transport path forming unit 83 and forms a drop path 84S through which the toner falls, a transport screw 85 that is rotatably arranged in the internal space 82S of the sub-hopper 82 and inside the transport path forming unit 83, and a toner transport motor 86 that rotates the transport screw 85.

[0021] The guide path forming portion 81 is made of, for example, a resin cylinder, and the internal space of the guide path forming portion 81 is a toner guide path 81S. The discharge outlet 72b of the toner container 72 is connected to the upstream portion of the guide path forming portion 81, and the guide path 81S extends downward. Therefore, the toner discharged from the discharge outlet 72b flows down along the guide path 81S and into the internal space 82S of the sub-hopper 82. The sub-hopper 82 has an opening on its top surface that is connected to the downstream end of the guide path forming portion 81, and an opening on its side surface that is connected to the upstream end of the transport path forming portion 83. The conveying screw 85 is arranged from the internal space 82S of the sub-hopper 82 to the internal space (toner conveying path 83S) of the conveying path forming section 83, and when rotated in the forward direction PR, it conveys the toner downstream as indicated by the arrow FF, and when rotated in the reverse direction NR, it conveys the toner upstream as indicated by the arrow BC.

[0022] Conveying screw 85 includes a rotary shaft 85a connected to toner conveying motor 86 and a spiral blade 85b provided integrally with rotary shaft 85a. In this embodiment, toner conveying path 83S has a circular cross section, and spiral blade 85b has a diameter substantially the same as that of toner conveying path 83S (more specifically, a diameter slightly smaller than that of toner conveying path 83S by an amount corresponding to a clearance), but is not limited to this configuration as long as it can convey toner in toner conveying path 83S. The toner transport motor 86 has a configuration in which its rotation direction can be switched between a forward direction PR and a reverse direction NR, and its operation is controlled by a control unit 100 (engine control unit 110) described later. In this embodiment, when the toner transport motor 86 rotates in the forward direction PR, the transport screw 85 also rotates in the forward direction PR, and when the toner transport motor 86 rotates in the reverse direction NR, the transport screw 85 also rotates in the reverse direction NR. The cooling fan 53 suppresses an excessive temperature rise in the guide path 81S by directing outside air into the image forming apparatus 1. In the example of FIG. 2, the cooling fan 53 is depicted near the transport path forming portion 83, but the position of the cooling fan 53 is not limited to the vicinity of the transport path forming portion 83. The cooling fan 53 may be provided in any position that allows it to direct outside air to the transport path forming portion 83. The drop path forming portion 84 communicates between the downstream end of the transport path forming portion 83 and the toner storage portion 93c.

[0023] The toner supply unit 80 having the above configuration supplies the toner stored in the toner container 72 to the toner image forming unit 42 (developer 93) by rotating the conveying screw 85 in the forward direction PR using the toner conveying motor 86. In addition, by rotating the conveying screw 85 in the reverse direction NR using the toner conveying motor 86, the toner in the toner conveying path 83S can also be conveyed to the upstream side BC.

[0024] <Hardware Configuration of Image Forming Apparatus 1> Next, a description will be given of the hardware configuration of the image forming apparatus 1. Fig. 4 is a diagram showing the hardware configuration of the image forming apparatus 1. As shown in Fig. 4, the control unit 100 controls the operations of the scanner unit 10, the paper feed unit 20, the paper transport unit 30, the image forming unit 40, and the cooling fan 53 based on input information from the operation unit 60 (input unit 62), temperature detection information from the temperature sensor 51, and humidity detection information from the humidity sensor 52. The control unit 100 includes a system control unit 120 (second control means) that is electrically connected to the operation unit 60, the temperature sensor 51, and the humidity sensor 52 and is capable of issuing notifications to an external terminal device 200 via the network NW, and an engine control unit 110 (first control means) that is electrically connected to the scanner unit 10, the paper feed unit 20, the paper transport unit 30, the image forming unit 40, and the cooling fan 53 and controls the operation of each unit.

[0025] During a period when a normal mode (first operation mode) in which an image forming operation can be performed is set, engine control unit 110 controls scanner unit 10, paper feed unit 20, paper transport unit 30, image forming unit 40, and cooling fan 53. Furthermore, engine control unit 110 does not control scanner unit 10, paper feed unit 20, paper transport unit 30, image forming unit 40, and cooling fan 53 during a power saving mode (second operation mode) in which power consumption is lower than in a normal mode such as a standby mode or a sleep mode. During the period when the normal mode is set and during the period when the power saving mode is set, the system control unit 120 receives input information from the operation unit 60 and detection information from the sensors 51 and 52. Furthermore, the system control unit 120 can transition the operation mode from the power saving mode to the normal mode and can start up the engine control unit 110 during the period when the power saving mode is set.

[0026] The engine control unit 110 includes a CPU (Central Processing Unit) 111 that controls the operation of the engine control unit 110, a ROM (Read Only Memory) 112 that is a read-only non-volatile storage medium that stores computer programs such as firmware, a RAM (Random Access Memory) 113 that is a volatile storage medium that allows high-speed reading and writing of information and is used as a working area when the CPU 111 processes information, and an interface (I / F) 114 that communicates with the system control unit 120. Similarly, the system control unit 120 also includes a CPU 121, a ROM 122, a RAM 123, and an I / F 124. Each of the CPUs 111 and 121 has an RTC (real-time clock) function, that is, a timekeeping function.

[0027] <Functional blocks of the control unit 100> Fig. 5 is a functional block diagram of the control unit 100. The functional blocks shown in Fig. 5 are realized by the CPUs 111 and 121 of the engine control unit 110 and the system control unit 120 loading programs stored in the ROMs 112 and 122 into the RAMs 113 and 123 and executing them. The engine control unit 110 includes a reading control unit 110A that controls the scanner unit 10 to read images, an image forming control unit 110B that controls the image forming unit 40 to form an image on paper P (recording medium), a paper feed / discharge control unit 110C that controls the paper feed unit 20 and the paper transport unit 30 to supply, transport, and discharge paper P, an anti-adhesion control unit 110D that controls the drive of the toner transport motor 86 to prevent toner from adhering in the toner transport path 83S, and a cooling control unit 110E that drives the cooling fan 53 to lower the temperature inside the machine. The system control unit 120 includes an input information acquisition unit 120A that acquires input information from the operation unit 60 (input unit 62), a notification control unit 120B that controls the notification of information to the display unit 61 and the terminal device 200, a communication control unit 120C that controls communication with the network NW, a usage history acquisition unit 120D that acquires the usage history of the image forming apparatus 1 (such as the time when the last image formation was performed), an environmental information acquisition unit 120E that stores the internal temperature and humidity based on detection signals from the temperature sensor 51 and the humidity sensor 52 in combination with information on the measurement time as environmental information (temperature information, humidity information) in RAM 123, and an adhesion determination unit 120F that determines whether to perform an operation to prevent adhesion of toner in the toner transport path 83S.

[0028] <Operation of Toner Supply Unit 80> Next, the operation of the toner supply unit 80 will be described. Fig. 6 is a schematic diagram illustrating the supply of toner G discharged from the toner container 72 (discharge port 72b) to the toner image forming unit 42, Fig. 7 is a schematic diagram illustrating the state where toner G' has started to adhere in the toner transport path 83S, Fig. 8 is a schematic diagram illustrating the state where aggregation of toner G' has progressed in the toner transport path 83S, Fig. 9 is a schematic diagram illustrating the state at the start of the adhesion prevention operation, Fig. 10 is a schematic diagram illustrating the state where toner G is transported to the toner image forming unit 42 side during the adhesion prevention operation, and Fig. 11 is a schematic diagram illustrating the state where toner G is transported to the toner container 72 side during the adhesion prevention operation.

[0029] As shown by the symbol R in FIG. 6, the toner container mount 41 rotates the toner container 72 about its axis, causing toner G to be discharged from the discharge port 72b of the toner container 72. The toner G discharged from the toner container 72 flows down the guide path 81S and reaches the internal space 82S of the sub-hopper 82. The toner G in the sub-hopper 82 is transported downstream through the toner transport path 83S by the rotation of the transport screw 85 in the forward direction PR. In this embodiment, the transport screw 85 rotates at a specified constant speed. When the toner G reaches the downstream end of the toner transport path 83S, it falls down the drop path 84S and flows into the toner image forming unit 42 (developer 93). 7, when the image forming apparatus 1 is left unused for a certain period of time, some of the toner G' may adhere to the toner conveying path 83S. As shown in FIG. 8, the toner G' adhered to the toner conveying path 83S tends to cause other toner G in the toner conveying path 83S to aggregate, and therefore, the toner G' gradually grows as the toner G is conveyed in the toner conveying path 83S.

[0030] If the stuck toner G' grows excessively, the conveying screw 85 will not be able to rotate even if a drive signal is supplied to the toner conveying motor 86, which may result in damage to the toner conveying motor 86. Therefore, if the toner sticking determination condition is met, the control unit 100 determines that there is a risk of toner G sticking, and executes a sticking prevention operation. The toner sticking determination condition can be the stop time of the toner conveying motor 86. For example, the control unit 100 (usage history acquisition unit 120D, sticking determination unit 120F) acquires the stop time of the toner conveying motor 86, and determines that the toner sticking determination condition is met if the stop time of the toner conveying motor 86 is equal to or longer than the determination reference time.

[0031] 9, in the sticking prevention operation, the control unit 100 first drives the toner conveyance motor 86 to rotate the conveyance screw 85 in the reverse direction NR. At this time, the rotation of the toner container 72 is stopped to prevent the toner G from being discharged from the toner container 72. The control unit 100 also drives the cooling fan 53 throughout the execution period of the sticking prevention operation to lower the temperature inside the machine by using the outside air FL that flows into the machine. This makes it difficult for the toner G in the conveyance path to melt, thereby suppressing the sticking of the toner G.

[0032] As the conveying screw 85 rotates in the reverse direction, the toner G in the toner conveying path 83S moves upstream (toward the toner container 72). By moving the toner G in the toner conveying path 83S upstream at the beginning of the adhesion prevention operation, the problem of the toner G' adhering in the toner conveying path 83S growing further can be suppressed. The reverse rotation time of the conveying screw 85 is set to a time shorter than the rotation time (toner G supply operation time) required to supply the toner G discharged into the toner conveying path 83S to the toner image forming unit 42. By setting the reverse rotation time of the conveying screw 85 to a time shorter than the toner G supply operation time, it is possible to prevent the toner G from accumulating too much in the upstream portion of the toner conveying path 83S or in the internal space 82S of the sub-hopper 82 when the adhesion prevention operation is performed.

[0033] 10, after the reverse rotation of the conveying screw 85 is completed, the control unit 100 drives the toner conveying motor 86 to rotate the conveying screw 85 in the forward direction PR. As the conveying screw 85 rotates forward, the toner G in the toner conveying path 83S moves downstream (toward the toner image forming unit 42). The forward rotation time of the conveying screw 85 is also set to a time shorter than the operation time for supplying the toner G. This prevents the problem of excessive accumulation of toner G in the downstream portion of the toner conveying path 83S due to the execution of the adhesion prevention operation. Thereafter, the conveying screw 85 is repeatedly rotated in the reverse direction (see FIG. 11) and the forward direction (see FIG. 10) until the condition for ending the adhesion prevention operation is met. By repeatedly rotating the conveying screw 85 in the reverse direction and the forward direction, the adhered toner G' is scraped off by the spiral blade 85b of the conveying screw 85 and broken into individual toner particles. As a result, the toner G is prevented from adhering in the toner conveying path 83S, and damage to the conveying screw 85 can be prevented. The end condition of the anti-sticking operation can be determined as appropriate. For example, the end condition can be determined based on the number of times the conveying screw 85 is rotated in the forward and reverse directions. Alternatively, the end condition can be determined based on the execution time of the anti-sticking operation.

[0034] Furthermore, when the sticking prevention operation is performed, the control unit 100 (notification control unit 120B) notifies the display unit 61 that the sticking prevention operation has been performed, and if there is a pre-registered notification destination (terminal device 200, see FIG. 4), notifies the notification destination that the sticking prevention operation has been performed. This allows the person who receives the notification to take appropriate action, such as cleaning or maintenance.

[0035] <Prevention of sticking in normal mode> The sticking prevention process executed by the control unit 100 will be described below. First, the sticking prevention process in normal mode (an operation mode in which image forming operations can be performed) will be described. Fig. 12 is a flowchart of the sticking prevention process in normal mode. This sticking prevention process is realized by the CPUs 111 and 121 of the engine control unit 110 and the system control unit 120 loading programs stored in ROMs 112 and 122 into RAMs 113 and 123 and executing them. The control unit 100 (usage history acquisition unit 120D) acquires as the stop time the time that has elapsed since the last operation of the toner conveying motor 86 ended (S1). The stop time of the toner conveying motor 86 is acquired, for example, based on the RTC function of the CPU 121 of the system control unit 120, but may also be acquired based on the RTC function of the CPU 111 of the engine control unit 110.

[0036] The control unit 100 (adhesion determination unit 120F) determines whether the toner sticking determination condition is met (S2). For example, the control unit 100 determines that the toner sticking determination condition is met if the stop time of the toner conveyance motor 86 acquired in step S1 is equal to or longer than the determination reference time (S2, Yes). On the other hand, the control unit 100 determines that the toner sticking determination condition is not met if the stop time of the toner conveyance motor 86 is shorter than the determination reference time (S2, No). If the control unit 100 determines that the toner adhesion determination condition is not satisfied, it ends the processing of the current cycle and moves on to the processing of the next cycle. Therefore, in the processing of step S1 described above, the stop time of the toner conveying motor 86 is periodically acquired.

[0037] After determining that the toner sticking determination conditions are met, the control unit 100 (adhesion prevention control unit 110D) executes the toner sticking prevention operation (S3). As described above, the control unit 100 rotates the conveying screw 85 in the reverse direction NR at the start of the toner sticking prevention operation, and then rotates the conveying screw 85 in the reverse direction NR. Thereafter, the control unit 100 switches the rotation direction of the conveying screw 85 between the forward direction PR and the reverse direction NR. By executing this toner sticking prevention operation, the inconvenience of toner G adhering to the toner conveying path 83S is suppressed. The control unit 100 determines whether the termination condition for the toner adhesion prevention operation is met throughout the execution of the toner adhesion prevention operation (S4). As described above, the termination condition can be determined as appropriate, such as the number of times the conveying screw 85 is rotated in the reverse and forward directions or the execution time of the toner adhesion prevention operation. If the termination condition is not met (S4, No), the control unit 100 continues the toner adhesion prevention operation (S3), and if the termination condition is met (S4, Yes), the control unit 100 terminates the toner adhesion prevention operation (S5).

[0038] <Prevention of sticking in power saving mode> Next, the sticking prevention process in the power saving mode (standby mode, sleep mode, etc.) will be described. Fig. 13 is a flowchart of the process for setting the execution interval of the sticking prevention operation in the power saving mode, Fig. 14 is a flowchart of the sticking prevention process by the system control unit 120, Fig. 15 is a flowchart of the sticking prevention process by the engine control unit 110, Fig. 16 is a flowchart of the transport path cooling process by the system control unit 120, and Fig. 17 is a flowchart of the transport path cooling process by the engine control unit 110. Each of these processes is realized by the CPUs 111, 121 of the engine control unit 110 and the system control unit 120 loading programs stored in the ROMs 112, 122 into the RAMs 113, 123 and executing them. In the power saving mode, the system control unit 120 (adhesion determination unit 120F) sets an interval for performing the operation to prevent toner G from adhering, and when the timing for performing the operation to prevent toner G from adhering arrives, the system control unit 120 cancels the power saving mode and starts the engine control unit 110 to perform the operation to prevent toner G from adhering. The engine control unit 110 performs the operation to prevent toner G from adhering, and then transitions to the power saving mode.

[0039] First, we will explain the execution interval setting process of the sticking prevention operation by the system control unit 120. In this execution interval setting process, temperature T1° C. is lower than temperatures T2° C. and T3° C., and temperature T2 is lower than temperature T3° C. Furthermore, execution interval Xh1 is longer than execution interval Xh2 and execution interval Xh3, and execution interval Xh2 is longer than execution interval Xh3. 13, the system control unit 120 (sticking determination unit 120F) determines whether or not it is time to update the execution interval of the sticking prevention operation (S11). The update timing is determined in advance and stored in the ROM 122 or the RAM 123. If the update timing has not arrived (S11, No), the system control unit 120 ends the processing of the current cycle and moves on to the processing of the next cycle. Therefore, in the processing of step S11 described above, it is periodically determined whether or not it is time to update.

[0040] When the system control unit 120 determines that the update timing has arrived (S11, Yes), it acquires the internal temperature based on the detection signal from the temperature sensor 51 (S12). Next, the system control unit 120 determines whether the acquired internal temperature is equal to or lower than temperature T1°C (S13), and if it is equal to or lower than temperature T1°C (S13, Yes), it sets the execution interval of the sticking prevention operation to the longest X1h (S14), and ends the processing of the current cycle. If the acquired internal temperature is not equal to or lower than temperature T1° C. (S13, No), the system control unit 120 determines whether the internal temperature is equal to or lower than temperature T2° C. (S15). If the internal temperature is equal to or lower than temperature T2° C. (S15, Yes), the system control unit 120 sets the execution interval of the sticking prevention operation to the second longest time, X2h (S16), and ends the processing of the current cycle. If the acquired internal temperature is not equal to or lower than temperature T2° C. (S15, No), the system control unit 120 sets the execution interval of the sticking prevention operation to the shortest interval of X3 hours (S17) and ends the processing of the current cycle.

[0041] By performing the above-described execution interval setting process, the execution interval of the sticking prevention operation is optimized. For example, the execution interval of the sticking prevention operation is set shorter as the internal temperature of the device increases.

[0042] Next, the sticking prevention process will be described. First, the sticking prevention process of the system control unit 120 will be described. As shown in Fig. 14, the system control unit 120 determines whether or not the power saving mode is set (S21), and if it determines that the power saving mode is not set (S21, No), it ends this process and executes other processes. Then, the system control unit 120 executes the process of step S21 at the start timing of the next cycle. When the system control unit 120 (usage history acquisition unit 120D) determines that the power saving mode is set (S21, Yes), it acquires the time that has elapsed since the last operation of the toner conveyance motor 86 ended as the stop time (S22). The system control unit 120 (sticking determination unit 120F) determines whether or not the timing to perform the sticking prevention operation has arrived (S23). For example, the system control unit 120 determines whether or not the timing to perform the sticking prevention operation has arrived based on the stop time of the toner conveyance motor 86 acquired in step S22 and the execution interval set in the execution interval setting process described above.

[0043] If the system control unit 120 determines that the timing to perform the anti-sticking operation has not arrived (S23, No), it ends the processing of the current cycle. If the system control unit 120 determines that the timing to perform the anti-sticking operation has arrived (S23, Yes), it starts up the engine control unit 110 (S24), and then sends an instruction to perform the anti-sticking operation to the engine control unit 110 when the power saving mode is released (when the mode is switched to normal mode) (S25). Next, the system control unit 120 (notification control unit 120B) performs a notification process to notify that there is a concern about the adhesion of toner G in the toner conveyance path 83S (S26). The notification process is, for example, a process to display a message on the operation unit 60 (display unit 61) or a process to send a message to the external terminal device 200, but other processes may be used as long as they can notify that there is a concern about the adhesion of toner G. Next, the system control unit 120 waits for operation completion information from the engine control unit 110 (S27), and when the operation completion information is received (S27, Yes), the series of processes ends.

[0044] Next, the sticking prevention process of the engine control unit 110 will be described. This sticking prevention process is started in conjunction with the startup process (S24) of the engine control unit 110 by the system control unit 120. As shown in Fig. 15, the engine control unit 110 cancels the power saving mode and sets the normal mode (S31), and waits for a command to execute the sticking prevention operation from the system control unit 120 (S32). Note that in this embodiment, the engine control unit 110 sets the normal mode, but the system control unit 120 may also set the normal mode. When the engine control unit 110 receives a command to perform the anti-adhesion operation (S32, Yes), it causes the cooling fan 53 to cool the toner conveying path 83S (S33), and also drives the conveying screw 85 to rotate and perform the anti-adhesion operation of the toner G (S34).

[0045] The engine control unit 110 determines whether the termination condition for the anti-sticking operation is met (S35), and if it determines that the termination condition is not met (S35, No), it continues the cooling operation (S33) of the toner conveying path 83S and the anti-sticking operation (S34), and if it determines that the termination condition is met (S35, Yes), it terminates the cooling operation and anti-sticking operation of the toner conveying path 83S (S36). Next, the engine control unit 110 transmits an operation completion report to the system control unit 120 (S37), and causes the system control unit 120 to transition to a power saving mode (S38), thereby completing the series of processes.

[0046] By carrying out the above-described sticking prevention process, the sticking prevention operation can be carried out even when the power saving mode is set.

[0047] <Transport path cooling process in power saving mode> Next, the conveying path cooling process will be described. The conveying path cooling process periodically acquires the internal temperature of the device, and when the internal temperature is equal to or higher than a specified temperature, drives the cooling fan 53 to cool the toner conveying path 83S. First, the transfer path cooling process of the system control unit 120 will be described. As shown in Fig. 16, the system control unit 120 determines whether or not the power saving mode is set (S41), and if it determines that the power saving mode is not set (S41, No), it ends this process and executes other processes. Then, the system control unit 120 executes the process of step S41 at the start timing of the next cycle. If the system control unit 120 determines that the power saving mode is set (S41, Yes), it determines whether or not the timing for acquiring the internal temperature has arrived (S42). The acquisition timing is determined in advance and stored in the ROM 122 or the RAM 123. If the system control unit 120 determines that the acquisition timing has not arrived (S42, No), it ends the processing for the current cycle.

[0048] When the system control unit 120 determines that the acquisition timing has arrived (S42, Yes), it acquires the internal temperature based on the detection signal from the temperature sensor 51 (S43), and determines whether the acquired internal temperature is equal to or higher than a specified temperature (S44). The specified temperature in the processing of step S44 is a temperature for determining whether to cool the toner conveying path 83S, and is stored in ROM 122 or RAM 123. When the internal temperature is lower than the specified temperature (S44, No), the system control unit 120 ends the processing of the current cycle. If the temperature inside the machine is above the specified temperature (S44, Yes), the system control unit 120 starts the engine control unit 110 (S45), and then, when the power saving mode is released (when the mode is switched to normal mode), it sends an instruction to the engine control unit 110 to execute the transport path cooling operation (S46). Next, the system control unit 120 waits for operation completion information from the engine control unit 110 (S47), and when the operation completion information is received (S47, Yes), the series of processes ends.

[0049] Next, the transfer path cooling process of the engine control unit 110 will be described. This sticking prevention process is started in conjunction with the startup process (S45) of the engine control unit 110 by the system control unit 120. As shown in Fig. 17, the engine control unit 110 cancels the power saving mode and sets the normal mode (S51), and waits for a command to execute the transfer path cooling operation from the system control unit 120 (S52). Note that in this embodiment, the engine control unit 110 sets the normal mode, but the system control unit 120 may also set the normal mode. When the engine control unit 110 receives the instruction to execute the conveying path cooling operation (S52, Yes), it causes the cooling fan 53 to cool the toner conveying path 83S (S53).

[0050] The engine control unit 110 determines whether or not a termination condition for the transfer path cooling operation is met (S54). The termination condition can be determined as appropriate, but examples of the termination condition include when the cooling fan 53 has been driven for a predetermined period of time, or when the temperature inside the machine has dropped below the above-mentioned specified temperature. If the engine control unit 110 determines that the termination condition is not met (S54, No), it continues the cooling operation of the toner conveying path 83S (S53), and if it determines that the termination condition is met (S54, Yes), it terminates the cooling operation of the toner conveying path 83S (S55). Next, the engine control unit 110 transmits an operation completion report to the system control unit 120 (S56), transitions to the power saving mode (S57), and ends the series of processes.

[0051] By performing the above-described conveying path cooling process, the toner conveying path 83S is appropriately cooled, and the adhesion of the toner G can be suppressed even when the power saving mode is set.

[0052] <About modified examples> The functions of the above-described embodiments can also be realized by one or more processing circuits. Here, the term "processing circuit" includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a conventional circuit module designed to perform each of the above-described functions.

[0053] In the above-described embodiment, the control unit 100 (adhesion determination unit 120F) determined that the anti-adhesion operation should be performed when the stop time of the toner conveying motor 86 was equal to or longer than the determination reference time (S2, Yes) or when the timing for performing the anti-adhesion operation had arrived (S23, Yes), but this configuration is not limited to this.

[0054] For example, the control unit 100 (adhesion determination unit 120F) may detect the rotational torque of the conveying screw 85 based on the drive signal (current value or pulse width) supplied to the toner conveying motor 86, and determine to perform anti-adhesion operation if the rotational torque is greater than or equal to a specified value. Similarly, the control unit 100 (adhesion determination unit 120F) may detect the rotation speed of the conveying screw 85 using an encoder or the like, and determine whether or not to perform anti-adhesion operation based on the rotation speed of the conveying screw 85 and the drive signal supplied to the toner conveying motor 86. For example, the detected rotation speed of the conveying screw 85 may be compared with the designed rotation speed corresponding to the drive signal, and if the detected rotation speed is similar to the designed rotation speed, it may be determined that anti-sticking operation does not need to be performed, but if it is excessively slow (for example, if it is below the reference speed), it may be determined that anti-sticking operation should be performed.

[0055] In the above-described embodiment, the system control unit 120 (sticking determination unit 120F) sets the execution interval of the sticking prevention operation based on the internal temperature of the machine, but this is not limiting. For example, the system control unit 120 (sticking determination unit 120F) may set the execution interval of the sticking prevention operation based on the set of the internal temperature and humidity of the machine (i.e., environmental information) and the stop time of the toner conveying motor 86.

[0056] In the above-described embodiment, the standby mode and the sleep mode are exemplified as the power saving mode, but the power saving mode is not limited to these operation modes. The power saving mode may be any operation mode that consumes less power than the normal mode in which image formation operations can be performed and in which the toner conveying motor 86 is not driven by the engine control unit 110.

[0057] In the above-described embodiment, the conveying screw 85 is exemplified as the conveying member, but the conveying member is not limited to the conveying screw 85. For example, a propeller having a plurality of blade members may be used instead of the spiral blade 85b.

[0058] In the above embodiment, the toner container 72 is exemplified as the toner containing means, but the toner containing means is not limited to the toner container 72. It is sufficient if the toner container has a configuration that can discharge the contained toner G into the toner conveyance path 83S.

[0059] In the above-described embodiment, paper P is used as an example of a recording medium on which an image is formed, but the recording medium is not limited to paper P. For example, various types of sheets such as postcards, envelopes, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, and OHP film may also be used.

[0060] [Summary of embodiments, actions, and effects of the present invention] <First embodiment> The image forming apparatus 1 of this embodiment comprises a toner conveying path 83S arranged between a toner container 72 (toner storage means) and a toner image forming section 42 (developing means), a conveying screw 85 (conveying member) that is rotated by a toner conveying motor 86 (drive motor) and conveys toner G along the toner conveying path 83S, and a control unit 100 (control means) that controls the toner conveying motor 86.When the conveying screw 85 is rotated in the forward direction PR, it conveys toner G downstream (towards the toner image forming section 42), and when rotated in the reverse direction NR, it conveys toner G upstream (towards the toner container 72).The control unit 100 drives the toner conveying motor 86 to switch the rotation direction of the conveying screw 85 between the forward direction PR and the reverse direction NR to perform an anti-sticking operation. According to the image forming apparatus 1 of this embodiment, the conveying screw 85 for supplying the toner G in the toner conveying path 83S to the toner image forming section 42 performs an operation to prevent the toner G from adhering, thereby simplifying the configuration for preventing the toner G from adhering.

[0061] <Second embodiment> In the image forming apparatus 1 according to this embodiment, the control unit 100 is configured to acquire the stop time of the toner conveying motor 86 (usage history acquisition unit 120D), and if the acquired stop time is equal to or longer than the judgment reference time (S2, Yes), executes an anti-sticking operation. According to the image forming apparatus 1 of this embodiment, it is possible to prevent the toner G from sticking to the toner transport path 83S due to the time when the toner transport motor 86 is stopped.

[0062] <Third embodiment> In the image forming apparatus 1 according to this embodiment, the control unit 100 is characterized by comprising an engine control unit 110 (first control means) that drives the toner conveying motor 86 during a period when a normal mode (first operation mode) in which image forming operations can be performed is set, and does not drive the toner conveying motor 86 during a period when a power saving mode (second operation mode) in which power consumption is lower than that of the normal mode is set, and a system control unit 120 (S24-S25, second control means) that determines whether or not to perform a sticking prevention operation during a period when the power saving mode is set (S23), and causes the engine control unit 110 to drive the toner conveying motor 86 if it is determined that a sticking prevention operation should be performed. According to the image forming apparatus 1 of this embodiment, it is possible to perform the sticking prevention operation even in the power saving mode.

[0063] <Fourth embodiment> The image forming apparatus 1 according to this embodiment is characterized by including a notification control unit 120B (notification means) that notifies the execution of the sticking prevention operation. According to the image forming apparatus 1 of this embodiment, it is possible to notify the execution of the sticking prevention operation.

[0064] <Fifth embodiment> The image forming apparatus 1 according to this embodiment is provided with a cooling fan 53 (cooling means) that performs cooling operation on the toner conveying path 83S, and a temperature sensor 51 (temperature measuring means) that measures the temperature inside the image forming apparatus 1 (internal temperature), and the control unit 100 is characterized in that when the temperature inside the apparatus is equal to or higher than a reference temperature, it causes the cooling fan 53 to perform cooling operation (S46, S53). According to the image forming apparatus 1 of this embodiment, the toner transport path 83S is appropriately cooled, so that the toner G can be prevented from sticking.

[0065] <Sixth embodiment> The image forming apparatus 1 according to this embodiment is characterized in that it is equipped with a temperature sensor 51 (temperature measuring means) that measures the temperature inside the image forming apparatus 1 (internal temperature), and the control unit 100 (system control unit 120, adhesion control unit 100) determines the interval at which anti-sticking operations are performed based on the temperature inside the apparatus. According to the image forming apparatus 1 of this embodiment, the intervals at which the sticking prevention operation is performed can be optimized.

[0066] <Seventh embodiment> In the image forming apparatus 1 according to this embodiment, the control unit 100 (engine control unit 110, anti-adhesion control unit 110D) is characterized in that the rotation time of the conveying screw 85 in the forward direction PR and the rotation time of the conveying screw 85 in the reverse direction NR during the anti-adhesion operation are set to be shorter than the rotation time of the conveying screw 85 required to supply the toner G in the toner conveying path 83S to the toner image forming unit 42. According to the image forming apparatus 1 of this embodiment, it is possible to prevent the toner G from accumulating too much in a portion of the toner conveying path 83S due to the execution of the sticking prevention operation.

[0067] <Eighth embodiment> In the image forming apparatus 1 according to this embodiment, the control unit 100 (engine control unit 110, anti-sticking control unit 110D) rotates the conveying screw 85 in the reverse direction NR at the start of the anti-sticking operation. According to the image forming apparatus 1 of this embodiment, it is possible to prevent the toner G' that has adhered to the inside of the toner transport path 83S from growing further.

[0068] <Ninth embodiment> The toner adhesion prevention method for the image forming apparatus 1 according to this embodiment is a method for preventing toner adhesion for the image forming apparatus 1, which is equipped with a toner transport path 83S arranged between the toner container 72 (toner storage means) and the toner image forming section 42 (developing means), and a transport screw 85 (transport member) that is rotated by a toner transport motor 86 and transports the toner G along the toner transport path 83S, wherein when the transport screw 85 is rotated in the forward direction PR, it transports the toner G downstream (towards the toner image forming section 42), and when rotated in the reverse direction NR, it transports the toner G upstream (towards the toner container 72), and the toner transport motor 86 is driven to switch the rotation direction of the transport screw 85 between the forward direction PR and the reverse direction NR to perform the adhesion prevention operation. According to the toner adhesion prevention method of this embodiment, the toner G adhesion prevention operation is performed by the conveying screw 85 for supplying the toner G in the toner conveying path 83S to the toner image forming section 42, thereby simplifying the configuration for preventing the toner G from adhering. [Explanation of symbols]

[0069] 1...image forming apparatus, 10...scanner unit, 11...original table, 12...reading mechanism, 20...paper feed unit, 21...paper feed cassette, 22...paper feed roller, 30...paper transport unit, 31...transport roller, 32A, 32B, 32C...paper discharge roller, 33A, 33B, 33C...stacking unit, 40...image forming unit, 41...toner container storage unit, 42 (42Y, 42C, 42M, 42K)...toner image forming unit (developing means), 43...exposure unit, 44...intermediate transfer belt, 45...fixing unit, 46...primary transfer bias roller, 47...secondary transfer roller pair, 51...temperature sensor (temperature measuring means), 52 ... humidity sensor, 53... cooling fan (cooling means), 60... operation unit, 61... display unit, 62... input unit, 71... toner container storage unit, 72 (72Y, 72M, 72C, 72K)... toner container (toner storage means), 72a... container body, 72b... discharge port, 80... toner supply unit, 81... guide path forming unit, 81S... guide path, 82... sub hopper, 82S... internal space of sub hopper, 83... conveying path forming unit, 83S... toner conveying path, 84... fall path forming unit, 84S... fall path, 85... conveying screw (conveying member), 85a... rotating shaft, 85b... spiral blade, 86... toner Conveying motor (driving motor), 91...photosensitive drum, 91a...drum body, 91b...image carrier, 92...charger, 93...developing device, 93a...developing roller, 93b...doctor blade, 93c, 93d...toner storage section, 93e...conveying screw, 94...cleaning section, 100...control section (control means), 110...engine control section (first control means), 110A...reading control section, 110B...image formation control section, 110C...paper feed / discharge control section, 110D...sticking prevention control section, 110E...cooling control section, 111...CPU, 112...ROM, 113...ROM, 114...ink Interface (I / F), 120...system control unit (second control means), 120A...input information acquisition unit, 120B...notification control unit, 120C...communication control unit, 120D...usage history acquisition unit, 120E...environment information acquisition unit, 120F...sticking determination unit, 121...CPU, 122...ROM, 123...ROM, 124...interface (I / F), 200...terminal device, G, G'...toner, FL...outside air, P...paper, PR...forward rotation direction of conveyor screw, NR...reverse rotation direction of conveyor screw, FP...paper conveyance path, L...laser light, NW...network [Prior art documents] [Patent documents]

[0070] [Patent Document 1] JP 2007-093639 A

Claims

1. a toner transport path disposed between the toner storage means and the developing means; a conveying member that is rotated by a drive motor and conveys the toner along the toner conveying path; a control means for controlling the drive motor; the conveying member conveys the toner toward the developing means when rotated in a forward direction, and conveys the toner toward the toner storage means when rotated in a reverse direction; the control means drives the drive motor to switch the rotation direction of the conveying member between the forward direction and the reverse direction to perform a sticking prevention operation; a first control means for driving the drive motor during a period when a first operation mode is set, and for not driving the drive motor during a period when a second operation mode, which consumes less power than the first operation mode, is set; and second control means for determining whether or not to execute the sticking prevention operation during the period in which the second operation mode is set, and for causing the first control means to drive the drive motor when it is determined that the sticking prevention operation should be executed.

2. 2. The image forming apparatus according to claim 1, wherein the control unit is configured to acquire a stop time of the drive motor, and executes the sticking prevention operation when the acquired stop time is equal to or longer than a reference time.

3. 3. The image forming apparatus according to claim 1, further comprising a notification unit that notifies the user that the sticking prevention operation has been performed.

4. a cooling unit for cooling the toner transport path; a temperature measuring unit for measuring an internal temperature of the image forming apparatus, 4. The image forming apparatus according to claim 1, wherein the control unit causes the cooling unit to perform the cooling operation when the internal temperature is equal to or higher than a reference temperature.

5. a temperature measuring unit for measuring an internal temperature of the image forming apparatus; 5. The image forming apparatus according to claim 1, wherein the control unit determines an interval for performing the sticking prevention operation based on the internal temperature.

6. 6. An image forming apparatus according to claim 1, wherein the control means sets the rotation time of the conveying member in the forward direction and the rotation time of the conveying member in the reverse direction during the anti-sticking operation to be shorter than the rotation time of the conveying member required to supply the toner in the toner conveying path to the developing means.

7. 7. The image forming apparatus according to claim 1, wherein the control unit rotates the conveying member in the reverse direction at the start of the sticking prevention operation.

8. A method for preventing toner adhesion in an image forming apparatus including: a toner transport path disposed between a toner storage means and a developing means; a transport member rotated by a drive motor to transport toner along the toner transport path; and a control means for controlling the drive motor, comprising: the conveying member conveys the toner toward the developing means when rotated in a forward direction, and conveys the toner toward the toner storage means when rotated in a reverse direction; the control means includes first control means that can drive the drive motor during a period in which a first operation mode is set and that does not drive the drive motor during a period in which a second operation mode that consumes less power than the first operation mode is set, and second control means that can activate the first control means during a period in which the second operation mode is set, During the period in which the first operation mode is set, the first control means drives the drive motor to switch the rotation direction of the conveying member between the forward direction and the reverse direction, thereby performing a sticking prevention operation; A method for preventing toner adhesion in an image forming apparatus, characterized in that during the period in which the second operating mode is set, the second control means determines whether or not to perform the adhesion prevention operation, and if it determines that the adhesion prevention operation should be performed, causes the first control means to drive the drive motor.

Images