Image forming apparatus

Abstract

To provide an image forming apparatus capable of determining the necessity of operation to fill conveying means with toner, even without providing a sensor that detects the presence or absence of toner for the conveying means that receives the toner from a cartridge in which the toner is accommodated and conveys the toner to the developing means.SOLUTION: An image forming apparatus 100 includes: developing means 3 that performs image formation using a toner accommodated in an attached cartridge to form a toner image on a photoreceptor drum 2; conveying means 80 that receives the toner from the cartridge and conveys the toner to the developing means 3; a toner sensor 39 that detects an amount of toner accommodated in the developing means 3; attachment / detachment detection means 161 that detects attachment and detachment of the cartridge; and control means 162 that has a storage section 164 and determines whether to perform filling operation to fill the conveying means with the toner on the basis of a filling determination variable stored in the storage section 164 when attachment of the cartridge is detected.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus that forms an image using toner accommodated in a mounted cartridge.

Background Art

[0002] Conventionally, an electrophotographic image forming apparatus has been known. In such an image forming apparatus, an image is formed (printed) using toner (developer) accommodated in a cartridge. The toner is consumed during image formation, and finally, the toner accommodated in the cartridge runs out. The empty cartridge is removed from the image forming apparatus, and a new cartridge is mounted.

[0003] In an image forming apparatus, a conveying means is provided for a developing device that forms a toner image to convey toner from a cartridge to the developing device. Therefore, an image forming apparatus has been proposed that determines a location where an abnormality has occurred in the toner supply path (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A conventional image forming apparatus includes a developer conveying means for conveying a developer to a developer accommodating portion, a first developer detecting means for detecting the developer conveyed by the developer conveying means, a second developer detecting means for detecting the developer in the developer accommodating portion, and a determination means for determining that the first developer detecting means is in an abnormal state when it is determined based on the detection result of the first developer detecting means that a predetermined developer to be conveyed by the developer conveying means has not been conveyed, and when it is determined based on the detection result of the second developer detecting means that a predetermined increase in the developer in the developer accommodating portion has occurred.

[0006] In a conventional image forming apparatus, a first developer detection means is provided to check whether a developer is being conveyed by a developer conveyance means. In the case of a configuration in which the first developer detection means is not provided in the developer conveyance means, there is a problem that it is impossible to determine whether a developer exists in the conveyance path.

[0007] The present disclosure has been made to solve the above problems, and an object thereof is to provide an image forming apparatus capable of determining the necessity of a toner filling operation for a developer conveyance means without providing a sensor for detecting the presence or absence of toner in the developer conveyance means.

Means for Solving the Problems

[0008] An image forming apparatus according to the present disclosure is an image forming apparatus that forms an image using toner accommodated in a mounted cartridge, and includes developing means for forming a toner image on an image carrier, conveyance means for receiving toner from the cartridge and conveying it to the developing means, a toner sensor for detecting the amount of toner accommodated in the developing means, attachment / detachment detection means for detecting attachment / detachment of the cartridge, and a storage unit. When the attachment / detachment detection means detects attachment of the cartridge, control means is provided for determining whether to perform a filling operation of filling the conveyance means with toner based on a filling determination variable stored in the storage unit.

[0009] In the image forming apparatus according to the present disclosure, the filling determination variable can be set to an initial value and a value different from the initial value. When the attachment / detachment detection means detects attachment of the cartridge, the control means may be configured to perform the filling operation when the value of the filling determination variable stored in the storage unit is the initial value, and not to perform the filling operation when the value of the filling determination variable is other than the initial value.

[0010] In the image forming apparatus according to the present disclosure, when the control means executes the filling operation, if the toner sensor detects an increase in the toner amount, the control means may stop the conveyance of the toner by the conveyance means, change the value of the filling determination variable to a value different from the initial value, and store the value in the storage unit.

[0011] In the image forming apparatus according to the present disclosure, which includes a display means, during the execution of the filling operation, if the toner sensor does not detect an increase in the toner amount even when the operation time of the conveyance means exceeds a specified time that is a preset time, the control means may stop the filling operation and cause the display means to display that an error has occurred.

[0012] In the image forming apparatus according to the present disclosure, when the value of the filling determination variable stored in the storage unit is a value other than the initial value and the toner sensor detects a toner amount less than a predetermined value, the control means may perform the conveyance of the toner by the conveyance means. If the toner amount detected by the toner sensor does not increase, the control means may determine that the toner in the cartridge is empty and set the filling determination variable to the initial value.

[0013] In the image forming apparatus according to the present disclosure, a plurality of the cartridges are detachable, and each cartridge is provided with the corresponding conveyance means and developing means. The lengths of the conveyance paths from the cartridges to the developing means of the plurality of conveyance means may be different from each other.

[0014] In the image forming apparatus according to the present disclosure, which includes a display means, during the execution of the filling operation, if there is a conveyance means that has not detected an increase in the toner amount even after exceeding an individual specified time that is a predetermined time determined according to the length of the conveyance path, the control means may stop the filling operation for the corresponding conveyance means and cause the display means to display that an error has occurred.

[0015] In the image forming apparatus according to the present disclosure, the plurality of cartridges may be arranged adjacent to each other, and the intervals between them may include those wider and those narrower than the intervals between the plurality of image carriers.

Advantages of the Invention

[0016] According to the present disclosure, even without providing a sensor for detecting the presence or absence of toner in the conveying means, when the cartridge is mounted on the main body, by referring to the value of the filling determination variable stored in the storage unit, it is possible to determine the necessity of the filling operation.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

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Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0018] Hereinafter, an image forming apparatus according to an embodiment of the present disclosure will be described with reference to the drawings.

[0019] FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to an embodiment of the present disclosure. Arrow X shown in the drawing indicates the left-right direction X when the image forming apparatus 100 is viewed from the front, and the direction indicated by arrow X is the right side. Arrow Y shown in the drawing indicates the depth direction Y of the image forming apparatus 100, with the front side being the front side with respect to the paper surface and the back side being the back side. Arrow Z shown in the drawing indicates the up-down direction Z when the image forming apparatus 100 is viewed from the front, and the direction indicated by arrow Z is the upper side.

[0020] The image forming apparatus 100 is a multifunction device having a copying function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document read by the image reading device 130 to the outside, or forms an image of a document read by the image reading device 130 or an image received from the outside in color or monochrome on a recording medium such as paper.

[0021] Above the image reading device 130, a document conveyance device 110 supported so as to be openable and closable is provided. The document conveyance device 110 conveys one or a plurality of documents one by one in order to the document reading position where the scanning optical system 130b is stopped. The image reading device 130 reads a document placed on the document placement table 130a by scanning the scanning optical system 130b, or reads a document conveyed by the document conveyance device 110 with the scanning optical system 130b stopped at the document reading position to generate image data.

[0022] The image forming apparatus 100 is provided with a fixing device 1, a photosensitive drum 2 (an example of an image carrier), developing means 3, a drum cleaning device 4, a charger 5, an intermediate transfer belt device 7, a secondary transfer device 11, an optical scanning device 12, and a paper feeding unit 18, etc.

[0023] In the image forming apparatus 100, image data corresponding to a color image using each of the colors black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (e.g., black) is handled. The image forming apparatus 100 is provided with four each of developing means 3 for forming four types of toner images, a photoreceptor drum 2, a drum cleaning device 4, and a charger 5, each of which is associated with black, cyan, magenta, and yellow, and four image stations Pa, Pb, Pc, and Pd are configured.

[0024] The photoreceptor drum 2 is an image carrier on which a toner image is formed with a photosensitive layer formed on its surface. The photosensitive layer exhibits insulating properties when not irradiated with light and has the property of changing to conductivity in the irradiated region. The charger 5 uniformly charges the surface (photosensitive layer) of the photoreceptor drum 2 to a predetermined potential. The optical scanning device 12 forms an electrostatic latent image by exposing the surface of the photoreceptor drum 2 charged to a predetermined potential based on the image data. The developing means 3 develops the electrostatic latent image formed on the surface of the photoreceptor drum 2 with toner to form a toner image on the surface of the photoreceptor drum 2. The drum cleaning device 4 removes and recovers the residual toner remaining on the surface of the photoreceptor drum 2 without being intermediate-transferred to the intermediate transfer belt device 7 described below. The surface of the photoreceptor drum 2 cleaned by the drum cleaning device 4 is discharged by a discharging device (not shown), and the electrostatic latent image formed on the surface of the photoreceptor drum 2 is erased. By the series of operations described above, toner images of each color are formed on the surface of each photoreceptor drum 2.

[0025] The intermediate transfer belt device 7 includes an endless intermediate transfer belt 71, an intermediate transfer driving roller 72, an intermediate transfer driven roller 73, an intermediate transfer roller 6, and a cleaning device 9. The intermediate transfer belt 71 is stretched between the intermediate transfer driving roller 72 and the intermediate transfer driven roller 73. The intermediate transfer roller 6 is provided inside the intermediate transfer belt 71 at positions corresponding to each of the photosensitive drums 2 on which four types of toner images corresponding to respective colors are formed. The intermediate transfer belt 71 is brought into contact with each photosensitive drum 2 by the intermediate transfer roller 6, and the toner images of respective colors formed on the surface of each photosensitive drum 2 are sequentially intermediate-transferred to the intermediate transfer belt 71 that moves in a circular motion as the intermediate transfer driving roller 72 rotates.

[0026] In the image forming apparatus 100, the toner images of respective colors formed on the surface of each photosensitive drum 2 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 71. The cleaning device 9 removes and collects the secondary transfer residual toner remaining on the surface of the intermediate transfer belt 71 without being transferred to the paper by the secondary transfer device 11 described later.

[0027] The secondary transfer device 11 has a secondary transfer roller 11a arranged to be in contact with the intermediate transfer belt 71. The secondary transfer device 11 sandwiches and conveys the paper conveyed through the paper conveyance path 21 in the transfer nip portion TN which is the region where the secondary transfer roller 11a and the intermediate transfer belt 71 are in contact. When the paper passes through the transfer nip portion TN, the toner image on the surface of the intermediate transfer belt 71 is transferred and the paper is conveyed to the fixing device 1.

[0028] The fixing device 1 includes a fixing belt 41 that rotates around an axis and a pressure roller 42 (an example of a pressure member). The fixing device 1 sandwiches, heats, and pressurizes the paper onto which the toner image has been transferred in the nip portion N which is the region where the fixing belt 41 and the pressure roller 42 are in contact, and fixes the toner image to the paper. Although not shown in FIG. 1, the fixing device 1 may also have constituent members other than the fixing belt 41 and the pressure roller 42.

[0029] The paper feeding unit 18 includes a paper feeding cassette for loading a recording medium (paper) used for image formation, and is provided below the optical scanning device 12. The paper is pulled out one by one from the paper feeding unit 18 by the pickup roller 16 and conveyed to the paper conveyance path 21. The paper conveyed to the paper conveyance path 21 is discharged to the paper discharge tray 19 by the discharge roller 17 via the secondary transfer device 11 and the fixing device 1.

[0030] In the paper conveyance path 21, a conveyance roller 13, a registration roller 14, and a discharge roller 17 are arranged. The conveyance roller 13 promotes the conveyance of the paper. The registration roller 14 conveys the paper at a speed equal to the process speed of performing image formation on the paper. This registration roller 14 is provided between the paper feeding unit 18 and the secondary transfer device 11, and adjusts the conveyance timing of the paper so that the toner image is transferred onto the paper by the secondary transfer device 11. For example, the registration roller 14 waits (stops temporarily) while sandwiching the paper conveyed from the paper feeding unit 18, and starts the conveyance of the paper so that the paper reaches the transfer nip portion TN at the timing when the toner image formed on the intermediate transfer belt 71 reaches the transfer nip portion TN.

[0031] When performing image formation not only on the front surface but also on the back surface of the paper, the discharge roller 17 changes the conveyance direction of the paper and conveys the paper to the reverse conveyance path 22. While the paper conveyed to the reverse conveyance path 22 is being conveyed to the registration roller 14 by the reverse conveyance roller 15, the front and back surfaces of the paper are reversed. The image forming apparatus 100 forms an image on the back surface of the paper guided to the registration roller 14 in the same manner as the front surface and discharges it to the paper discharge tray 19.

[0032] The image forming apparatus 100 is configured to mount a cartridge 140 for accommodating toner, and toner is supplied from the cartridge 140 to the developing means 3 via a conveyance means 80 described later. In the present embodiment, four cartridges 140 corresponding to each color to be used are mounted, and each cartridge 140 is detachable from the image forming apparatus 100.

[0033] FIG. 2 is a perspective view showing the cartridge, and FIG. 3 is a perspective view showing the connection terminal attached to the cartridge.

[0034] The cartridge 140 is a container that houses toner in a space provided inside, and a connection terminal 142 connected to the image forming apparatus 100 is provided at an end portion. The connection terminal 142 has a memory mounted inside and stores information regarding the cartridge 140. Examples of the information regarding the cartridge 140 include, but are not limited to, the color of the stored toner and the size of the cartridge 140, and may appropriately include other information.

[0035] The cartridge 140 includes a discharge port 143 for discharging the toner stored inside and a cartridge gear 141 that rotates by receiving the rotational force of a toner supply motor 150, which will be described later, at an end portion opposite to the side where the connection terminal 142 is disposed. Further, the cartridge 140 includes a screw 144 inside for stirring and conveying the stored toner. The end of the screw 144 is connected to the cartridge gear 141, and the cartridge gear 141 rotates by receiving the rotational force of the toner supply motor 150. When the screw 144 rotates by the rotational force received via the cartridge gear 141, the toner stored inside is conveyed toward the discharge port 143. The toner conveyed to the discharge port 143 by the screw 144 drops from the discharge port 143 and is conveyed to a conveying means 80, which will be described later. Note that a developer (so-called two-component developer) including toner and a carrier may be stored in the cartridge 140.

[0036] The image forming apparatus 100 is provided with a recess corresponding to the connection terminal 142, and a sensor (an example of the attachment / detachment detection means 161) for detecting whether the connection terminal 142 exists in the recess is provided. Then, based on the detection result by the sensor, the attachment / detachment of the cartridge 140 can be detected. That is, the image forming apparatus 100 includes the attachment / detachment detection means 161 for detecting the attachment / detachment of the cartridge 140. Note that the method for detecting the attachment / detachment of the cartridge 140 is not limited to this, and an engagement terminal for communicating with the memory in the connection terminal 142 may be provided in the image forming apparatus 100. In this configuration, by connecting the connection terminal 142 to the engagement terminal provided in the image forming apparatus 100, the information stored in the memory in the connection terminal 142 can be read out, and the attachment / detachment of the cartridge 140 may be detected based on whether communication with the memory in the connection terminal 142 is possible or whether the information stored in the memory in the connection terminal 142 can be read out.

[0037] FIG. 4 is a cross-sectional view of a main part showing the cartridge and the conveying means.

[0038] In FIG. 4, a cross-section of a part of the cartridge 140 and the conveying means 80 is shown. In the present embodiment, the image forming apparatus 100 is configured to accommodate four cartridges 140 (a first cartridge 140a to a fourth cartridge 140d). Among the four cartridges 140, the first cartridge 140a, the second cartridge 140b, and the third cartridge 140c are substantially the same, and the fourth cartridge 140d is larger in size than the others. The four cartridges 140 are arranged side by side in one direction (in FIG. 4, the left-right direction) so as to be adjacent to each other, and the fourth cartridge 140d has a larger width occupied in the arranged direction. The fourth cartridge 140d preferably corresponds to a toner having a large size and a large usage amount, and for example, contains black (K) toner.

[0039] As described above, the cartridge 140 is provided with a discharge port 143 for discharging toner. The discharge port 143 is provided at the bottom of the cartridge 140 and is connected to an inlet 81 of the conveying means 80 provided below the discharge port 143 in the vertical direction Z. Although details are omitted, the cartridge 140 is provided with a shutter for opening and closing the discharge port. In a state where the cartridge 140 is removed from the image forming apparatus 100, the shutter is closed to prevent toner leakage, and in a state where the cartridge 140 is mounted on the image forming apparatus 100, the shutter is opened to enable toner supply.

[0040] Four conveying means 80 (first conveying means 80a to fourth conveying means 80d) are provided corresponding to the four cartridges 140 and the developing means 3. The conveying means 80 includes an inlet 81 connected to the discharge port 143 of the corresponding cartridge 140, a supply port 82 connected to a receiving port 37 (see FIG. 7 described later) provided in the corresponding developing device 3, a conveying path 83 for conveying the toner received from the inlet 81 to the respective supply ports 82, and a conveying member 84 (conveying screw) provided in the conveying path 83.

[0041] Here, the supply port 82 is provided so as to be offset (shifted in position) in the left-right direction X rather than directly below the inlet 81 in the vertical direction Z. The offset distance OF shown in FIG. 4 represents the distance by which the supply port 82 is shifted in the left-right direction X with respect to the inlet 81. Further, the conveying paths 83 in the first conveying means 80a to the third conveying means 80c are arranged to incline downward from the horizontal direction, for example, at an angle α (25 degrees in the present embodiment) from the inlet 81 side toward the supply port 82 side, and the conveying path 83 in the fourth conveying means 80d is arranged horizontally from the inlet 81 side toward the supply port 82 side.

[0042] At the end of the conveying screw 84, a conveying gear 85 is attached. It rotates by the driving force transmitted through the conveying gear 85, and conveys the toner that has fallen through the inlet 81 and been fed into the conveying path 83 toward the end on the supply port 82 side, which is directly above the supply port 82. The toner that reaches the end on the supply port 82 side falls from there and is fed into the developing device 3 from the lower supply port 82. That is, the conveying means 80 receives the toner from the cartridge 140 and conveys it to the developing means 3.

[0043] And the four conveying means 80 are configured such that the lengths of the conveying paths 83 from the cartridge 140 to the developing means 3 are different. Specifically, the lengths of the conveying paths 83 are configured to increase in the order of the length DLa of the conveying path 83 of the first conveying means 80a, the length DLd of the conveying path 83 of the fourth conveying means 80d, the length DLb of the conveying path 83 of the second conveying means 80b, and the length Dc of the conveying path 83 of the third conveying means 80c. By configuring in this way, the size (toner storage volume) of the cartridge 140 can be changed according to the usage frequency and the like as described above. In the present embodiment, the size (storage volume) of the cartridge 140d that stores the frequently used black toner is made larger than that of the other cartridges.

[0044] FIG. 5 is a perspective view of a main part showing the relationship between the cartridge, the conveying means, and the drive source.

[0045] The image forming apparatus 100 is provided with a toner supply motor 150 for driving the cartridge 140 and the conveying means 80, and a transmission mechanism composed of a plurality of gears and the like. The driving force of the toner supply motor 150 is transmitted to the cartridge gear 141 and the conveying gear 85 through the transmission mechanism, rotating the corresponding screw. Note that the transmission mechanism may be provided with a one-way clutch for regulating the rotation direction, a clutch for controlling the transmission of the driving force, and the like. The toner supply motor 150 and the transmission mechanism are included in the toner supply means 80.

[0046] FIG. 6 is a perspective view showing the internal structure of the developing means. In FIG. 6, in order to facilitate viewing the inside of the developing means 3, a state in which a part of the housing of the developing means 3 is removed is shown.

[0047] The developing means 3 includes a housing 31, a developing roller 32, a first screw 33, and a second screw 34. The housing 31 has a space inside that houses the developing roller 32, the first screw 33, the second screw 34, and a developer containing toner, and is substantially rectangular in shape. In the present embodiment, a two-component developer containing toner having no magnetism and a carrier having magnetism is used. The space of the housing 31 is partitioned into two regions by a partition wall 35 extending along the longitudinal direction. The partition wall 35 is provided with openings 38 at portions corresponding to both ends in the longitudinal direction (depth direction Y). The opening 38 provided at the end on the back side is the first opening 381, and the opening 38 provided at the end on the front side is the second opening 382.

[0048] The first screw 33 is provided in one region of the space inside the housing 31 partitioned by the partition wall 35, and the second screw 34 is provided in the other region. The first screw 33 and the second screw 34 are arranged facing each other with their axes parallel. Developing gears 36 are connected to the axes of the first screw 33 and the second screw 34, respectively, and the first screw 33 and the second screw 34 rotate by the rotational force from a drive source (not shown) transmitted through the developing gears 36.

[0049] Further, the housing 31 is provided with a receiving port 37 at the front end for receiving toner conveyed from the conveying means 80. The toner received from the receiving port 37 is conveyed to the back side by the second screw 34. The toner conveyed to the back end by the second screw 34 is sent to the area where the first screw 33 is arranged through the first opening 381. The toner sent to the area where the first screw 33 is arranged through the first opening 381 is conveyed to the front side by the first screw 33. The toner conveyed to the front end by the first screw 33 is sent to the area where the second screw 34 is arranged through the second opening 382. In this way, the developer accommodated in the space partitioned by the partition wall 35 having openings 38 at both ends is circulated by rotating the first screw 33 and the second screw 34.

[0050] The developing roller 32 is provided so as to face the photosensitive drum 2, and a part of the developer conveyed by the first screw 33 is supplied and carried on the surface. Then, only the toner is supplied from the developer carried on the surface to the photosensitive drum 2. In the present embodiment, the developing roller 32 is arranged above the first screw 33, but it is not limited thereto. The developing roller 32 may be provided facing the part of the developing means 3 that supplies the developer to the outside. The receiving port 37 provided at the end of the housing 31 is connected to the discharge port 82 of the corresponding conveying means 80. Further, a toner sensor 39 (see FIGS. 6 and 8) for detecting the amount of toner accommodated in the developing device 3 is attached to the housing 31 to detect the amount of toner in the housing 31. In the present embodiment, a magnetic permeability sensor for detecting the amount of toner from the magnetic permeability of the carrier is used as the toner sensor 39.

[0051] FIG. 7 is a schematic cross-sectional view showing the positional relationship among the cartridge, the conveying means, and the photosensitive drum.

[0052] In FIG. 7, four cartridges 140, the conveying means 80 corresponding to each of the four cartridges 140, the photoreceptor drum 2, and the developing means 3 are extracted and shown. In the present embodiment, the four photoreceptor drums 2 are arranged at substantially constant intervals. For example, with respect to the interval between the second photoreceptor drum 2b and the third photoreceptor drum 2c (the first drum distance DL1), the interval between the third photoreceptor drum 2c and the fourth photoreceptor drum 2d (the second drum distance DL2) is substantially equal. In the present embodiment, the first drum distance DL1 and the second drum distance DL2 are both 65 mm.

[0053] As described above, regarding the cartridges 140, those with different sizes are mixed, so there are differences in the intervals between the cartridges 140. Specifically, with respect to the interval between the second cartridge 140b and the third cartridge 140c (the first cartridge distance CL1), the interval between the third cartridge 140c and the fourth cartridge 140d (the second cartridge distance CL2) is wider. Also, the first cartridge distance CL1 is narrower than the first drum distance DL1 and the second drum distance DL2, while the second cartridge distance CL2 is wider than the first drum distance DL1 and the second drum distance DL2.

[0054] More specifically, the first cartridge distance CL1 in the present embodiment is 48.5 mm, and the second cartridge distance CL2 is 85 mm. Since the first drum distance DL1 and the second drum distance DL2 are 65 mm, the first cartridge distance CL1 is shorter than the first drum distance DL1 and the second drum distance DL2, and the second cartridge distance CL2 is longer than the first drum distance DL1 and the second drum distance DL2.

[0055] Thus, the plurality of cartridges 140 are configured such that the intervals between them include those wider and those narrower than the interval between the photoreceptor drums 2. This is achieved by adjusting the lengths of the respective conveyance paths 83 in the plurality of conveyance means 80 (the first conveyance means 80a to the fourth conveyance means 80d). That is, by changing the lengths of the conveyance paths 83 of the respective cartridges 140, it is possible to mix the plurality of cartridges 140 such that some have an interval wider than that between the photoreceptor drums 2 and some have an interval narrower than that, and it is possible to vary the sizes of the cartridges 140.

[0056] In the image forming apparatus 100, control is performed to keep the amount of toner in the developing means 3 constant. When toner is consumed by image formation and the amount of toner detected by the toner sensor 39 becomes smaller than a predetermined value, the toner supply motor 150 is driven to supply toner from the cartridge 140 to the developing means 3. By the way, at the time of shipment, the cartridge 140 is in a removed state and is to be mounted before use. At this time, the conveyance means 80 is not filled with toner, and even if the toner supply motor 150 is driven, toner is not immediately supplied to the developing means 3. Therefore, in the present embodiment, when the mounting of the cartridge 140 is detected, a filling operation for filling the conveyance means 80 with toner is performed.

[0057] FIG. 8 is a schematic configuration diagram of the image forming apparatus according to the present embodiment. Note that in FIG. 8, a part of the image forming apparatus 100 is extracted and shown, and other members not shown in FIG. 8 may be appropriately provided.

[0058] In addition to the photosensitive drum 2, developing means 3, toner sensor 39, attachment / detachment detection means 161, and conveyance means 80 described above, the image forming apparatus 100 includes a control means 162 and a display means 165. The control means 162 has a processing unit 163 and a storage unit 164. The processing unit 162 is a microcomputer such as a CPU mounted on the image forming apparatus 100, and the storage unit 164 includes a non-volatile memory such as a ROM mounted on the image forming apparatus 100 and a volatile memory such as a RAM. The control means 162 controls the operation of the image forming apparatus 100 by having the processing unit 163 load a control program stored in advance in the ROM of the storage unit 164 onto the RAM of the storage unit 164 and execute it. For example, it causes the filling operation described later to be executed. A filling determination variable described later is stored in the non-volatile memory of the storage unit 164. The display means 165 is a touch panel, a liquid crystal display, or the like for performing a predetermined operation on the image forming apparatus 100, and the operation content and the content of the error that has occurred are displayed.

[0059] FIG. 9 is a flowchart showing a processing flow related to the filling operation in the image forming apparatus according to the present embodiment.

[0060] In the processing flow shown in FIG. 9, the time when the cartridge 140 is attached to the image forming apparatus 100 is set as the start time of the processing.

[0061] In step S01, the attachment / detachment detection means 161 detects that the cartridge 140 has been attached. Here, the control means 162 reads the filling determination variable stored in the storage unit 164 and checks its value. The filling determination variable stored in the storage unit 164 is a variable for determining whether or not the conveyance path 83 is filled with toner. At the time of shipment, a value of "0" is stored as the initial value. As described above, at the time of factory shipment, the conveyance path 83 is not filled with toner, so the value of the initial value, "0", means that the conveyance path 83 is not filled with toner. Note that as long as the filling determination variable can determine that the conveyance path 83 is not filled with toner, the value stored in the filling determination variable may be a specific symbol, for example, a character such as "empty".

[0062] Also, the value of the filling determination variable can be set to an initial value and a value different from the initial value. After performing the filling operation, it is changed to a value different from the initial value, for example, "1", and the changed value is stored in the storage unit 164. This is just an example, and after performing the filling operation, it may be changed to a specific symbol or character such as "full". By doing so, it is possible to determine whether the toner is filled in the transport path 83 based on the value stored in the filling determination variable. That is, even if a sensor for detecting the presence of toner in the transport path 83 is not provided, it is possible to determine whether there is toner in the transport path 83.

[0063] In step S02, the control means 162 determines whether to perform the filling operation based on the value of the filling determination variable read from the storage unit 164. Here, when the filling determination variable is the initial value, the control means 162 causes the filling operation to be performed, and when the filling determination variable is other than the initial value, the control means 162 does not cause the filling operation to be performed. As a result, if it is determined to perform the filling operation (step S02: Yes), the process proceeds to step S03. On the other hand, if it is determined not to perform the filling operation (step S02: No), the process ends. In other words, when the attachment / detachment detection means 161 detects the attachment of the cartridge 140, the control means 162 proceeds to step S03 when the value of the filling determination variable stored in the storage unit 164 is the initial value, and when the value of the filling determination variable is other than the initial value, the control means 162 does not execute the filling operation and thus ends the process.

[0064] In step S03, the control means 162 operates the transport means 80 and measures the filling time. Here, the filling time corresponds to the operation amount of the transport means 80, and it may be simply the time for rotating the transport screw 84, or it may be the number of rotations of the transport screw 84. The transport screw 84 is controlled to rotate at a constant speed, and the number of rotations is determined according to the rotation time.

[0065] In step S04, the control means 162 checks the detected value of the toner sensor 39 and determines whether the toner amount in the housing 31 has increased. When detecting the toner amount by the toner sensor 39, it is preferable that the developing means 3 is operating. Therefore, the developing means 3 may start the rotation operations of the first screw 33, the second screw 34, and the developing roller 32 in accordance with the start of the conveying operation by the conveying means 80, or may start the operation earlier than the conveying means 80.

[0066] And when the toner sensor 39 detects an increase in the toner amount (step S04: Yes), as described above, the value of the filling determination variable is changed to a value different from the initial value and stored in the storage unit 164, and the process ends. In other words, when the filling operation is performed, if the toner sensor 39 detects an increase in the toner amount, the control unit 162 stops the conveyance of the toner by the conveying means 80, changes the value of the filling determination variable to a value different from the initial value, and stores it in the storage unit 164.

[0067] On the other hand, if the filling time, which is the operation time of the conveying means 80, exceeds a specified time (for example, 2 minutes), which is a predetermined time, and the toner sensor 39 does not detect an increase in the toner amount (step S04: No), the filling operation is stopped and the process proceeds to step S05.

[0068] In step S05, the control means 162 displays an error occurrence message on the display means 165 and ends the process. Here, an error message indicating that toner has not been supplied due to the installation of the cartridge 140 is displayed on the display means 165. That is, during the execution of the filling operation, if the filling time of the conveying means 80 exceeds the specified time, which is the preset time, and the toner sensor 39 does not detect an increase in the toner amount, the control means 162 stops the filling operation and displays on the display means 165 that an error has occurred. Note that the display means 165 may be a speaker, a lamp, etc., as long as it can notify the user that an error has occurred. In this case, the user can be notified of the occurrence of an error by sound, light, etc.

[0069] As described above, in the image forming apparatus 100, based on the pre-stored filling determination variable (value), it is determined whether to perform the filling operation. Therefore, even if a sensor for detecting the presence or absence of toner is not provided in the conveying means 80, when the cartridge 140 is attached to the main body, by referring to the filling determination variable, the necessity of the filling operation can be determined. Further, by appropriately setting the filling determination variable, it is possible to easily switch between a state where the filling operation is necessary and a state where it is not. Therefore, even when the communication with the memory in the connection terminal 142 of the cartridge 140 becomes impossible, or when measures are taken to improve the contact state between the connection terminal 142 and the engagement terminal by detaching and attaching the cartridge 140, it becomes possible to easily determine the necessity of the filling operation.

[0070] Further, when the control means 162 performs the filling operation and the toner sensor 39 detects an increase in the toner amount, that is, when it becomes Yes in step S04, the control means 162 stops the conveyance of the toner by the conveyance means 80 and changes the filling determination variable to a value different from the initial value. In this way, since the filling operation is terminated after detecting an increase in the toner amount, it is possible to surely make the state where the toner can be replenished.

[0071] Also, in step S03, the control means 162 may increase the filling determination variable as the conveyance means 80 is operated during the filling operation. The filling determination variable here may be the filling time. In this way, it can be set to the filling determination variable corresponding to the operation amount of the conveyance means 80, and the operation amount necessary for the filling operation can be grasped.

[0072] Regarding step S04, the determination may be made after the elapse of a specified time, which is a preset time after the start of the filling operation. That is, in the filling operation, even if the filling time, which is the operation time of the conveying means 80, exceeds the specified time, if the toner sensor 39 does not detect an increase in the toner amount, the filling operation is stopped and an error is notified. In this way, when the toner amount does not increase even when the filling operation is performed, it can be predicted that some malfunction has occurred, so the operation can be stopped at an appropriate timing.

[0073] The specified time may be set according to the length of the conveyance path 83 of the corresponding conveying means 80. That is, for the first conveying means 80a with a short conveyance path 83, a short specified time is set, and for the third conveying means 80c with a long conveyance path 83, a long specified time is set. Note that it is not necessary to set the specified time according to the operation amount required to reach from the inlet 81 to the outlet 82, and the specified time may be set according to the operation amount with a little margin. Hereinafter, for the sake of explanation, the specified time defined according to the length of the conveyance path 83 may be sometimes referred to as an individual specified time.

[0074] In the image forming apparatus 100, not only when the cartridge 140 is mounted, but also in accordance with the execution of image formation, the toner amount in the developing means 3 is detected and toner is appropriately replenished. During the replenishment operation, even if the value obtained by adding a predetermined time, which is the time required for discharging the toner in the cartridge 140, to the individual specified time defined according to the length of the conveyance path 83 is exceeded, if the toner sensor 39 does not detect an increase in the toner amount, it is determined that the toner in the cartridge 140 is empty. Then, the filling determination variable is changed to the initial value and stored in the storage unit 164, and a message prompting the replacement of the cartridge 140 with a new one is displayed on the display means 165.

[0075] That is, even when the amount of toner in the developing device 3 decreases during the image forming operation, the processes from step S03 to step S05 are performed. In this way, by returning the filling determination variable to the initial value when the cartridge 140 becomes empty, it becomes possible to determine that the filling operation is required for the corresponding conveying means 80.

[0076] It should be noted that the embodiments disclosed this time are illustrative in all respects and do not serve as a basis for a restrictive interpretation. Therefore, the technical scope of the present disclosure is not interpreted only by the above-described embodiments, but is defined based on the description of the claims. Also, all changes within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0077] 2 Photoconductor drum (an example of an image carrier) 3 Developing means 39 Toner sensor 80 Conveying means 100 Image forming apparatus 150 Toner replenishment motor 161 Attachment / detachment detection means 162 Control unit

Claims

1. An image forming apparatus that forms an image using toner stored in a mounted cartridge, comprising: developing means for forming a toner image on an image carrier; transport means for receiving toner from the cartridge and transporting it to the developing means; a toner sensor for detecting the amount of toner stored in the developing means; attachment / detachment detection means for detecting attachment / detachment of the cartridge; a control means having a storage unit, and when the attachment / detachment detection means detects attachment of the cartridge, determining whether to perform a filling operation of filling the transport means with toner based on a filling determination variable stored in the storage unit. An image forming apparatus characterized by this.

2. The image forming apparatus according to claim 1, wherein the filling determination variable can be set to an initial value and a value different from the initial value, and the control means performs the filling operation when the value of the filling determination variable stored in the storage unit is the initial value when the attachment / detachment detection means detects attachment of the cartridge, and does not perform the filling operation when the value of the filling determination variable is a value other than the initial value. An image forming apparatus characterized by this.

3. The image forming apparatus according to claim 2, wherein when the control means performs the filling operation and the toner sensor detects an increase in the amount of toner, the control means stops the transport of toner by the transport means, changes the value of the filling determination variable to a value different from the initial value, and stores it in the storage unit. An image forming apparatus characterized by this.

4. The image forming apparatus according to claim 1, comprising display means, and when the control means is performing the filling operation and the toner sensor does not detect an increase in the amount of toner even when the operation time of the transport means exceeds a specified time that is a preset time, the control means stops the filling operation and displays that an error has occurred on the display means. An image forming apparatus characterized by this.

5. The image forming apparatus according to claim 2, wherein when the value of the filling determination variable stored in the storage unit is a value other than the initial value and the toner sensor detects an amount of toner less than a predetermined value, the control means performs the transport of toner by the transport means, and when the amount of toner detected by the toner sensor does not increase, determines that the toner in the cartridge is empty and sets the filling determination variable to the initial value. An image forming apparatus characterized by this.

6. The image forming apparatus according to claim 1, wherein a plurality of said cartridges are detachable, and said conveyance means and said developing means corresponding to each of said cartridges are provided, wherein lengths of conveyance paths from said cartridges to said developing means of said plurality of said conveyance means are different from each other, and an image forming apparatus characterized by this.

7. The image forming apparatus according to claim 6, including display means, wherein, during execution of said filling operation, when there is a conveyance means in which the toner sensor has not detected an increase in the toner amount even after exceeding an individual specified time which is a predetermined time determined according to the length of said conveyance path, said control means stops said filling operation for the corresponding conveyance means and causes said display means to display that an error has occurred, and an image forming apparatus characterized by this.

8. The image forming apparatus according to claim 7, wherein a plurality of said cartridges are arranged adjacent to each other, and intervals between them include those wider and those narrower than an interval between a plurality of said image carriers, and an image forming apparatus characterized by this.

Images