Image forming apparatus

Abstract

To provide an image forming apparatus capable of suppressing deterioration in detection accuracy of a toner residual amount.SOLUTION: An image forming apparatus 101 includes an image carrier 48, a developer storage part, a first electrode and a second electrode disposed inside the developer storage part, a first electrical contact 64 electrically connected to the first electrode, a second electrical contact 65 electrically connected to the second electrode, a first substrate 71 for applying a voltage to the first electrical contact 64, and a detection circuit for detecting a detection current flowing between the first electrode and the second electrode. The image forming apparatus includes a first substrate 71, a second substrate 81 independent of the first substrate 71, and a control unit configured to acquire a remaining amount of developer stored in a developer storage unit based on a detection current detected by the second substrate 81, wherein a shortest distance between the second substrate 81 and the second electrical contact 66 is shorter than a shortest distance between the first substrate 71 and the second electrical contact 65. In at least one of the first direction, the second direction, and the third direction, a distance between the second substrate 81 and the second electrical contact 65 is shorter than a distance between the first substrate 71 and the second electrical contact 65.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that utilizes an electrophotographic system. [Background technology]

[0002] An electrophotographic image forming apparatus forms an image by transferring a toner image formed on the surface of a photosensitive drum using a developer such as toner onto a transfer material (recording material) as a recording medium. A known configuration of such an image forming apparatus includes a toner storage unit that stores toner and a toner amount detection unit that detects the amount of toner in the toner storage unit.

[0003] Patent Document 1 discloses a toner amount detection means using a capacitance method. The capacitance method, for example, involves arranging two electrodes in a toner storage unit to form a capacitance, and detecting and acquiring the remaining toner amount by detecting the current between the electrodes using a current detection circuit connected to one of the electrodes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-108173 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the capacitance-type developer remaining amount detection, for example, the signal line connecting the electrode and the current detection circuit may be affected by stray capacitance between the signal line and a nearby frame or another signal line, which can reduce the accuracy of current detection. This reduction in current detection accuracy leads to a reduction in the accuracy of developer remaining amount detection.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus that can prevent a decrease in the accuracy of detecting the remaining amount of developer. [Means for solving the problem]

[0007] In order to achieve the above object, an image forming apparatus according to the present invention comprises: an image carrier configured to be rotatable about a rotation axis and on whose surface an electrostatic latent image is formed; a developer container that contains a developer for developing the electrostatic latent image; a first electrode and a second electrode disposed opposite each other inside the developer accommodating portion; a first electrical contact electrically connected to the first electrode; a second electrical contact electrically connected to the second electrode; a first substrate electrically connected to the first electrical contact and configured to apply a voltage to the first electrical contact; a second substrate electrically connected to the second electrical contact, configured to detect a detection current flowing between the first electrode and the second electrode, and independent of the first substrate; a control unit that acquires a remaining amount of the developer contained in the developer container based on the detected current detected by the second substrate; Equipped with the shortest distance between the second substrate and the second electrical contact is shorter than the shortest distance between the first substrate and the second electrical contact; When the direction of the rotation axis and the direction perpendicular to the rotation axis are defined as a first direction and a second direction, respectively, and a direction perpendicular to both the first direction and the second direction is defined as a third direction, in at least one of the first direction, the second direction, and the third direction, The distance between the second substrate and the second electrical contact is shorter than the distance between the first substrate and the second electrical contact. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus capable of suppressing a decrease in the accuracy of detecting the remaining amount of developer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 10 is a block diagram showing the configuration of a toner remaining amount detecting device according to a comparative example. [Figure 3] 1 is an explanatory diagram of the layout configuration of a remaining toner amount detecting device according to a first embodiment. [Figure 4] 1 is an explanatory diagram of the layout configuration of a remaining toner amount detecting device according to a first embodiment. [Figure 5] 1 is a block diagram showing a configuration of a toner remaining amount detecting device according to a first embodiment. [Figure 6] FIG. 10 is an explanatory diagram of a toner remaining amount detecting device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. The dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of the present invention is not limited to the following embodiments.

[0011] In the following description, the present invention will be described as being applied to an image forming apparatus of an electrophotographic image forming type that forms an image on a recording medium using an electrophotographic image forming process. Electrophotographic image forming apparatuses include, for example, electrophotographic copying machines, electrophotographic printers (LED printers, laser beam printers, etc.), electrophotographic facsimile machines, etc.

[0012] Example 1 (Image forming device) First Embodiment An image forming apparatus 101 according to a first embodiment of the present invention will be described. The image forming apparatus 101 is a laser beam printer that uses an electrophotographic process. Fig. 1 is a schematic cross-sectional view showing the general configuration of the image forming apparatus 101 according to the first embodiment.

[0013] In the following description and drawings, the depth direction of the image forming apparatus 101 is defined as the X direction, the width direction as the Y direction, and the up-down direction as the Z direction. The X direction, Y direction, and Z direction intersect with each other (orthogonal in the first embodiment), and when the image forming apparatus 101 is placed on a horizontal placement surface, the up-down direction (Z direction) is parallel to the direction of gravity.

[0014] The image forming apparatus 101 includes a paper feed cassette 104 that stores recording material S, which is a recording medium. The image forming apparatus 101 also includes a paper feed roller 141 that feeds out the recording material S from the paper feed cassette 104, a pair of conveying rollers 142, a top sensor 143 that detects the leading edge of the recording material S, and a pair of registration rollers 144 that synchronously convey the recording material S. These are arranged in the order of paper feed roller 141, conveying roller pair 142, top sensor 143, and registration roller pair 144 from the upstream side in the conveying direction of the recording material S. In the following description, unless otherwise specified, the conveying direction refers to the conveying direction of the recording material S fed from the paper feed roller 141.

[0015] A cartridge 15 configured to be detachable from the apparatus main body 101a of the image forming apparatus 101 is disposed downstream in the conveying direction of the registration roller pair 144. The cartridge 15 forms a toner image on the recording material S based on laser light from a laser scanner 106.

[0016] The cartridge 15 is composed of a photosensitive drum 48, a primary charging roller 47, a developing roller 46, etc., which are necessary for the electrophotographic process. Furthermore, the cartridge 15 is provided with a toner storage section (developer storage section) 60 therein that stores toner T as a developer.

[0017] The photosensitive drum 48 is configured to be rotatable about a rotation axis and is an image carrier on whose surface an electrostatic latent image is formed. The developing roller 46 is a supplying member that supplies toner contained in a toner containing section 60 to the surface of the photosensitive drum 48. The primary charging roller 47 is a charging member that charges the photosensitive drum 48. An electrostatic latent image is formed on the surface of the photosensitive drum 48, and the electrostatic latent image is developed with toner T supplied by the developing roller 46. In this way, a toner image is formed on the surface of the photosensitive drum 48.

[0018] A transfer roller 145 is provided at a position facing the photosensitive drum 48. A transfer nip is formed between the photosensitive drum 48 and the transfer roller 145. The toner image formed on the surface of the photosensitive drum 48 is transferred onto the recording material S at the transfer nip.

[0019] The image forming apparatus 101 includes a heat fixing device 103 for thermally fixing a toner image formed on a recording material S. The heat fixing device 103 is a heating device having a fixing film 149, a pressure roller 150, a heater 102 disposed inside the fixing film 149, and a thermistor 109 disposed near the heater 102 so as to detect the temperature of the heater 102 inside the fixing film 149. The heat fixing device 103 is disposed downstream of the cartridge 15 in the conveying direction.

[0020] The image forming apparatus 101 includes a pair of paper discharge rollers 151 that discharges the recording material S, on which the toner image has been thermally fixed, to the outside. The pair of paper discharge rollers 151 are disposed downstream of the heat fixing unit 103 in the conveying direction.

[0021] The image forming apparatus 101 includes a power supply unit (power supply device) 120. The power supply unit 120 can switch between outputting a voltage of 24 V or 10 V as appropriate, and generates a voltage of 24 V in print mode or standby mode. The power supply unit 120 supplies the voltage of 24 V as a drive system voltage to drive units (not shown) such as motors and clutches, a high-voltage power supply (not shown) for supplying high voltage to the cartridge 15, a polygon mirror drive unit (not shown) of the laser scanner 106, and the like. The voltage supply from the power supply unit 120 to each drive unit is performed via a control unit 123.

[0022] The image forming apparatus 101 includes a control unit 123 that controls the image forming apparatus 101. The control unit 123 is an engine controller that controls the aforementioned drive unit to operate each roller that constitutes the conveyance unit for the recording material S, thereby controlling the conveyance of the recording material S. Furthermore, the control unit 123 controls the laser scanner 106, cartridge 15, heat fixing unit 103, etc. to perform an image formation (hereinafter referred to as printing) operation. The control unit 123 may also perform various calculation processes (for example, calculation of remaining toner amount) described below. A processing device having calculation resources such as a processor and memory can be used as the control unit 123.

[0023] A DC-DC converter 121 is mounted inside the control unit 123, and generates a voltage of 3.3 V that is mainly used in the control system based on the voltage supplied from the power supply unit 120. The voltage of 3.3 V is then supplied to a control circuit (not shown) inside the control unit 123, and control system circuits including a video controller 131 (described later), a laser light emitting unit (not shown) of the laser scanner 106, a top sensor 143, and the like.

[0024] The image forming apparatus 101 includes a video controller 131. The video controller 131 is connected to the control unit 123 via an engine interface 133, and is also connected to an external device such as a personal computer via a general-purpose external interface 134 (USB, etc.). The device 132 is connected to the power supply 131.

[0025] The video controller 131 receives print information (number of copies, various settings, etc.) and print data from the external interface 134. The video controller 131 then uses an internal image control unit (not shown) to convert the print data into image data that can actually be printed. Thereafter, the control unit 123 is configured to receive image data from the video controller 131 via the engine interface 133 at a predetermined timing and send it to the laser scanner 106.

[0026] The cartridge 15 is a toner cartridge equipped with a toner storage section 60 that stores toner T therein. A first electrode 61 and a second electrode 62 that form a capacitance, and a toner agitating member 63 are arranged inside the toner storage section 60. The first electrode 61 and the second electrode 62 are arranged facing each other inside the toner storage section 60.

[0027] When the toner T in the toner storage unit 60 is stirred by the toner stirring member 63, the toner T moves in and out between the first electrode 61 and the second electrode 62 (the opposing space). The capacitance between the first electrode 61 and the second electrode 62 changes as the toner T moves in and out. In the first embodiment, the change in capacitance due to the movement of the toner T is utilized to detect the current flowing between the first electrode 61 and the second electrode 62, and the control unit 123 detects the remaining amount of toner based on the detected current.

[0028] Image forming apparatus 101 includes a toner remaining amount detection unit 50 that detects the amount of remaining toner by passing a current between first electrode 61 and second electrode 62 and detecting the current. Toner remaining amount detection unit 50 is configured with a plurality of electrical contacts, a circuit for outputting a voltage, a circuit for detecting the current, etc. The configuration of toner remaining amount detection unit 50 will be described in detail later.

[0029] [Comparative example of a toner remaining amount detection device] Prior to describing the toner remaining amount detecting device according to the first embodiment, a toner remaining amount detecting device according to a comparative example will be described below. Fig. 2 is a block diagram showing the configuration of a toner remaining amount detecting device of an electrostatic detection type according to the comparative example.

[0030] The toner remaining amount detection device of the comparative example is composed of a toner remaining amount detection unit 50, a first electrode 61, a second electrode 62, a first electrical contact 64 electrically connected to the first electrode 61, a second electrical contact 65 electrically connected to the second electrode 62, and a control unit 123.

[0031] The remaining toner amount detection unit 50 includes a remaining toner amount detection board 51 that includes an AC voltage output circuit 72 and a current detection circuit 82. The AC voltage output circuit 72 is electrically connected to the first electrical contact 64, and is a circuit for outputting (generating) a voltage to be applied to the first electrical contact 64. The current detection circuit 82 is electrically connected to the second electrical contact 65, and is a circuit for detecting the current flowing between the first electrode 61 and the second electrode 62. In other words, the remaining toner amount detection unit 50 functions as both an AC voltage output unit and a current detection unit.

[0032] The first electrode 61 and the second electrode 62 are provided inside the toner storage unit 60. The first electrical contact 64 and the second electrical contact 65 are provided on the surface of the cartridge 15. The first electrical contact 64 is electrically connected to the first electrode 61 and is connected to the AC voltage output circuit 72 via a signal line (AC voltage line) 66. The second electrical contact 65 is electrically connected to the second electrode 62 and is connected to the current detection circuit 82 via a signal line 67. The signal line 67, the AC voltage output circuit 72, and the current detection circuit 82 are each connected to a frame GND (ground). In the following description and drawings, the frame GND will be simply referred to as FG.

[0033] The AC voltage generated by the AC voltage output circuit 72 is applied to the first electrical contact 64 via a signal line 66, causing a current to flow according to the capacitance between the first electrode 61 and the second electrode 62. The current flowing between the first electrode 61 and the second electrode 62 flows into a current detection circuit 82 via a signal line 67. The current detection circuit 82 detects the current that has flowed in, and the control unit 123 obtains the remaining toner amount based on the detected current.

[0034] When the capacitance between the first electrode 61 and the second electrode 62 is small, the current flowing into the current detection circuit 82 is also small. As a result, the signal line 67 between the second electrode 62 and the current detection circuit 82 is significantly affected by the stray capacitance Cs1 between the second electrode 62 and the FG and the stray capacitance Cs2 between the signal line 67 and the signal line 66 from the AC voltage output circuit 72 to the first electrode 61. The signal line 67 is also susceptible to crosstalk noise with the signal line 66 and crosstalk noise with other signal lines. When the signal line 67 is affected by these factors, the current detection accuracy of the current detection circuit 82 decreases, making it difficult to accurately detect and acquire the remaining toner amount.

[0035] In order to reduce the effects of stray capacitance and crosstalk noise, it is necessary to ensure large distances such as the distance Lfg between the signal line 67 and FG, the distance Lac between the signal line 67 and the signal line 66, and the distance between the signal line 67 and other signal lines. However, increasing the distance between the signal line 67 and other components is not desirable because it may lead to an increase in the size of the remaining toner amount detection device, that is, an increase in the size of the image forming apparatus 101.

[0036] [Toner remaining amount detection device of embodiment 1] Next, a description will be given of a toner remaining amount detection device according to Example 1. In the comparative example, AC voltage output circuit 72 and current detection circuit 82 are provided on one board (toner remaining amount detection board 51), but in Example 1, AC voltage output circuit 72 and current detection circuit 82 are provided on two independent boards that are located apart from each other. Hereinafter, in the configuration of the toner remaining amount detection device of Example 1, elements that are similar to those in the comparative example will be given the same reference numerals, and descriptions thereof will be omitted.

[0037] 3 is an explanatory diagram of the layout configuration of an electrostatic toner remaining amount detection device according to the first embodiment, and is a diagram of an image forming apparatus 101 viewed from above in the direction of gravity downward. The toner remaining amount detection device according to the first embodiment is configured with an AC voltage output unit 70 including a first board (voltage output board) 71, and a current detection unit 80 including a second board (current detection board) 81 independent of the first board 71. The first board 71 has an AC voltage output circuit 72 and applies a voltage to the first electrical contact 64. The second board 81 has a current detection circuit 82 and detects a detection current flowing between the first electrode 61 and the second electrode 62.

[0038] In the first embodiment, the current detection unit 80 is disposed above (directly above) the cartridge 15. More specifically, when viewed in the direction of gravity, the second substrate 81 is disposed at a position overlapping with the cartridge 15. The first electrical contact 64 and the second electrical contact 65 are disposed on the surface of the cartridge 15. The first electrical contact 64 and the second electrical contact 65 are disposed side by side in a direction parallel to the rotation axis C1 of the photosensitive drum 48.

[0039] When viewed in the direction of gravity, both the first electrical contact 64 and the second electrical contact 65 are positioned so as to overlap the second substrate 81 of the current detection unit 80 and the photosensitive drum 48 of the cartridge 15. On the other hand, the AC voltage output unit 70 including the first substrate 71 is disposed in a position so as not to overlap the first electrical contact 64, the second electrical contact 65, or the cartridge 15 when viewed in the direction of gravity.

[0040] 3, in a direction parallel to the rotation axis C1 of the photosensitive drum 48 (first direction, Y direction), the second substrate 81 of the current detection unit 80 is provided at a position closer to the second electrical contact 65 than the first substrate 71 of the AC voltage output unit 70. In the direction parallel to the rotation axis C1 (first direction, Y direction), a first distance L1 between the second substrate 81 and the second electrical contact 65 is shorter than a second distance L2 between the first substrate 71 and the second electrical contact 65. In Example 1, the second substrate 81 and the second electrical contact 65 overlap when viewed in the direction of gravity, so the first distance L1 is zero. Furthermore, in Example 1, the distance between the second substrate 81 and the first electrical contact 64 is shorter than the distance between the first substrate 71 and the first electrical contact 64 in the direction parallel to the rotation axis C1 (first direction, Y direction).

[0041] Furthermore, in the first embodiment, the second substrate 81 is also located closer to the second electrical contact 65 than the first substrate 71 in the directions (second direction, X direction) perpendicular to both the rotation axis C1 of the photosensitive drum 48 and the direction of gravity. That is, in the directions (second direction, X direction) perpendicular to both the rotation axis C1 and the direction of gravity, the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65. Similarly, in the directions (second direction, X direction) perpendicular to both the rotation axis C1 and the direction of gravity, the distance between the second substrate 81 and the first electrical contact 64 is shorter than the distance between the first substrate 71 and the first electrical contact 64.

[0042] 4 is an explanatory diagram of the layout configuration of the electrostatic toner remaining amount detection device according to the first embodiment, and is a diagram of the toner remaining amount detection unit 50 and the cartridge 15 as viewed in the direction of the rotation axis C1 of the photosensitive drum 48. In FIG. 4, only the main components are shown to illustrate the positional relationship between the toner remaining amount detection unit 50 and the cartridge 15. As shown in FIG. 3, the first electrical contact 64 and the second electrical contact 65 are arranged side by side in a direction parallel to the rotation axis C1 of the photosensitive drum 48 (Y direction), but in FIG. 4 they are shown shifted in the Y direction to illustrate their connection relationship.

[0043] 4, the second substrate 81 is located closer to the second electrical contact 65 than the first substrate 71 in the direction perpendicular to the rotation axis C1. In other words, a third distance L3, which is the shortest distance between the second substrate 81 and the second electrical contact 65 in the direction perpendicular to the rotation axis C1, is shorter than a fourth distance L4, which is the shortest distance between the first substrate 71 and the second electrical contact 65. Similarly, the distance between the second substrate 81 and the first electrical contact 64 in the direction perpendicular to the rotation axis C1 is shorter than the distance between the first substrate 71 and the first electrical contact 64.

[0044] 4, in Example 1, the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65 in a predetermined direction (e.g., the second direction) perpendicular to the rotation axis C1. Furthermore, in a direction (a third direction, e.g., the Z direction) perpendicular to both the direction of the rotation axis C1 (the first direction) and the predetermined direction (the second direction) perpendicular to the rotation axis C1, the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65. Thus, in Example 1, the second substrate 81 is located closer to the second electrical contact 65 than the first substrate 71 in each of the first direction, the second direction, and the third direction. The components are arranged so that the shortest distance between the second substrate 81 and the second electrical contact 65 is shorter than the shortest distance between the first substrate 71 and the second electrical contact 65.

[0045] 5 is a block diagram showing the configuration of the toner remaining amount detecting device according to the first embodiment. A first board 71 of the AC voltage output unit 70 has an AC voltage output circuit 72. A second board 81 of the current detecting unit 80 has a current detecting circuit 82. The first board 71 and the second board 81 are each connected to FG.

[0046] The first electrical contact 64, which is electrically connected to the first electrode 61, and the second electrical contact 65, which is electrically connected to the second electrode 62, are each connected to a second substrate 81 of the current detection unit 80. The first electrical contact 64 is electrically connected to the AC voltage output circuit 72 in the AC voltage output unit 70 via the second substrate 81. With this configuration, the signal line 66 The signal line 67 can be connected to the second board 81 via a similar route, which leads to a reduction in wiring space.

[0047] In the configuration of Example 1, the AC voltage output unit 70 and the current detection unit 80 are electrically connected by a cable, and the current detection unit 80 is electrically connected to the first electrical contact 64 and the second electrical contact 65 by contact springs. Note that the electrical connection configuration is not limited to this configuration, and other connecting members (connecting means) may be used as long as they can provide electrical connection. Also, in Example 1, the first board 71 of the AC voltage output unit 70 is connected to the first electrical contact 64 via the second board 81 of the current detection unit 80, but the first board 71 may be connected to the first electrical contact 64 without going through the second board 81.

[0048] When deciding whether to place the first substrate 71 or the second substrate 81 closer to the second electrical contact 65, in the first embodiment, the second substrate 81 is placed closer to the second electrical contact 65 than the first substrate 71 of the AC voltage output unit 70. This in turn shortens the distance of the signal line 67 connecting the current detection circuit 82 and the second electrode 62, thereby reducing the influence of stray capacitance generated between the signal line 67 and other potentials and crosstalk noise due to other signals. This therefore makes it possible to suppress a decrease in the accuracy of current detection and to suppress a decrease in the accuracy of remaining toner detection.

[0049] Furthermore, by shortening the signal line 67, it is possible to reduce the space required to ensure the distance between the signal line 67 and other signal lines (such as Lfg and Lac in FIG. 2 ) that was required in the comparative example. Furthermore, by providing a separate second substrate 81 included in the current detection unit 80, the size of the current detection unit 80 can be reduced, making it easier to arrange the current detection unit 80 near the second electrical contact 65. Furthermore, by providing the separate first substrate 71 included in the AC voltage output unit 70 and the separate second substrate 81 included in the current detection unit 80, it is possible to arrange the AC voltage output unit 70 and the current detection unit 80 apart from each other. Therefore, it is possible to reduce the influence of noise generated in the AC voltage output circuit 72 on the current detection unit 80.

[0050] As described above, according to the first embodiment, by arranging the current detection unit 80 near the second electrical contact 65, it is possible to provide an image forming apparatus 101 with high accuracy in detecting the amount of remaining toner, and also to contribute to the miniaturization of the apparatus. Note that in the first embodiment, the first electrode 61 and the second electrode 62 are provided exclusively for the capacitance configuration, but the first electrode 61 may also be shared with an electrode connected to the developing roller 46 (supply member) or the like. By sharing the electrode, the number of electrodes that need to be arranged is reduced, which further contributes to the miniaturization of the apparatus. For the same reason, the first electrical contact 64 may be configured to receive power to be supplied to the developing roller 46 from the apparatus main body 101a.

[0051] In the first embodiment, the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65 in both the direction of the rotation axis C1 (first direction) and a predetermined direction (second direction) perpendicular to the rotation axis C1. However, for example, if the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65 in at least one of the first and second directions, the effect of suppressing a decrease in the accuracy of detecting the remaining toner amount is greater than the opposite layout. This is because the signal line 67 connecting the current detection circuit 82 of the second substrate 81 and the second electrical contact 65 can be shortened by arranging the second substrate 81 closer to the second electrical contact 65 than the first substrate 71 in at least one of the first and second directions. In other words, it is sufficient that the shortest distance between the second substrate 81 and the second electrical contact 65 is shorter than the shortest distance between the first substrate 71 and the second electrical contact 65, and that the distance between the second substrate 81 and the second electrical contact 65 is shorter than the distance between the first substrate 71 and the second electrical contact 65 in at least one of the first direction, the second direction, and the third direction.

[0052] <Example 2> Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the support configuration of the second substrate 81. Only the differences between the configuration of the second embodiment and the configuration of the first embodiment will be described below. The same components in the second embodiment as those in the first embodiment will be assigned the same reference numerals, and their description will be omitted. The second embodiment is configured to be able to suppress failure of electronic components in the current detection unit 80 due to ESD (Electro-Static Discharge).

[0053] The configuration of the second embodiment will be described with reference to Fig. 6. Fig. 6 is an explanatory diagram of a toner remaining amount detecting device according to the second embodiment, and is a diagram of an image forming apparatus 101 viewed in the direction of the rotation axis C1 of the photosensitive drum 48. Fig. 6 shows the positional relationship between the cartridge 15 and the second board 81 of the current detecting unit 80. Electronic components 83 for configuring a current detecting circuit 82 are mounted on the second board 81 of the current detecting unit 80.

[0054] Support members 91 and 92 for supporting second substrate 81 are attached to second substrate 81. Furthermore, support member 91 is connected to protective member 93, and support member 92 is connected to protective member 94. Protective members 93 and 94 are both components connected to device body 101a of image forming apparatus 101. In other words, second substrate 81 is attached to device body 101a of image forming apparatus 101 by support members 91 and 92 and protective members 93 and 94.

[0055] A cartridge 15 that is detachable from the device body 101a of the image forming apparatus 101 is disposed below the second substrate 81. When the cartridge 15 is attached to the device body 101a, the second electrical contact 65 and the second substrate 81 are connected by a contact spring 90.

[0056] The second substrate 81 has a first surface 81a on which electronic components 83 are provided, and a second surface 81b that is the back surface of the first surface 81a. The second substrate 81 is disposed so that the second surface 81b faces the electrical contacts (the first electrical contacts 64 and the second electrical contacts 65). That is, in the second embodiment, the first surface 81a faces upward in the direction of gravity, and the second surface 81b faces downward in the direction of gravity.

[0057] In addition to contact spring 90, which is a connecting member, protective members 93 and 94 are arranged in the space between second substrate 81 and second electrical contact 65. Protective members 93 and 94 are provided to cover second surface 81b of second substrate 81 while ensuring a space for connecting members such as contact spring 90 to pass through, and constitute a protective section for protecting second substrate 81.

[0058] That is, the second substrate 81 is arranged so that the first surface 81a on which the electronic components 83 are provided faces away from the second electrical contacts 65, and the lower part of the second substrate 81 is covered, except for a portion, by the protective members 93 and 94. With this configuration, even if ESD occurs to the first electrical contacts 64 or the second electrical contacts 65 due to a user operation when attaching or detaching the cartridge 15, the second substrate 81 acts as a barrier to the electronic components 83, and damage due to aerial discharge of ESD can be suppressed.

[0059] As described above, according to the second embodiment, it is possible to suppress a decrease in the accuracy of detecting the remaining toner amount, and also to suppress a failure of the electronic component 83 caused by ESD caused by user operations.

[0060] The disclosure of this embodiment includes the following configuration. (Configuration 1) an image carrier configured to be rotatable about a rotation axis and on whose surface an electrostatic latent image is formed; a developer container that contains a developer for developing the electrostatic latent image; a first electrode and a second electrode disposed opposite each other inside the developer accommodating portion; a first electrical contact electrically connected to the first electrode; a second electrical contact electrically connected to the second electrode; a first substrate electrically connected to the first electrical contact and configured to apply a voltage to the first electrical contact; a second substrate electrically connected to the second electrical contact, configured to detect a detection current flowing between the first electrode and the second electrode, and independent of the first substrate; a control unit that acquires a remaining amount of the developer contained in the developer container based on the detected current detected by the second substrate; Equipped with the shortest distance between the second substrate and the second electrical contact is shorter than the shortest distance between the first substrate and the second electrical contact; An image forming apparatus characterized in that, when the direction of the rotation axis and the direction perpendicular to the rotation axis are defined as a first direction and a second direction, respectively, and a direction perpendicular to both the first direction and the second direction is defined as a third direction, the distance between the second substrate and the second electrical contact is shorter than the distance between the first substrate and the second electrical contact in at least one of the first direction, the second direction, and the third direction. (Configuration 2) The image forming apparatus described in configuration 1, characterized in that the distance between the second substrate and the second electrical contact is shorter than the distance between the first substrate and the second electrical contact in any of the first direction, the second direction, and the third direction. (Configuration 3) 3. The image forming apparatus according to claim 1, wherein the distance between the second substrate and the second electrical contact in the direction of gravity is shorter than the distance between the first substrate and the second electrical contact. (Configuration 4) The image forming apparatus according to any one of configurations 1 to 3, wherein the second substrate has a first surface on which electronic components are provided and a second surface that is the reverse side of the first surface, and is arranged so that the second surface faces the second electrical contact. (Configuration 5) 5. The image forming apparatus according to claim 4, wherein the electronic component is a component that constitutes a current detection circuit for detecting the detection current. (Configuration 6) a connection member that electrically connects the second substrate and the first electrical contact; a protective member provided to cover the second surface of the second substrate while ensuring a space through which the connecting member passes; 6. The image forming apparatus according to configuration 4 or 5, comprising: (Configuration 7) 7. The image forming apparatus according to any one of configurations 1 to 6, wherein the first electrical contact is electrically connected to the first substrate via the second substrate. (Configuration 8) a supply member that supplies the toner contained in the developer container to the image carrier; 8. The image forming apparatus according to any one of configurations 1 to 7, wherein the first electrode supplies electricity to the supply member. (Configuration 9) a supply member that supplies the toner contained in the developer container to the image carrier; 9. The image forming apparatus according to any one of configurations 1 to 8, wherein the first electrical contact receives power to be supplied to the supply member. (Configuration 10) a device body on which the first substrate and the second substrate are provided; The image carrier, the developer container, the first electrical contact, and the second electrical contact are provided. a cartridge configured to be detachable from the device main body; The image forming apparatus according to any one of configurations 1 to 9, further comprising: (Configuration 11) 11. The image forming apparatus according to claim 10, wherein the second substrate is disposed above the cartridge and at a position overlapping the cartridge when viewed in the direction of gravity. (Configuration 12) 12. The image forming apparatus according to claim 11, wherein the first substrate is disposed at a position that does not overlap with the cartridge when viewed in the direction of gravity. (Configuration 13) an apparatus main body in which the first substrate, the second substrate, and the image carrier are provided; a cartridge provided with the developer accommodating portion, the first electrical contact, and the second electrical contact, the cartridge being detachably attached to the main body of the apparatus; The image forming apparatus according to any one of configurations 1 to 9, further comprising: [Explanation of symbols]

[0061] 48...photosensitive drum, 60...toner storage section (developer storage section), 61...first electrode, 62...second electrode, 64...first electrical contact, 65...second electrical contact, 71...first substrate, 81...second substrate, 123...control section

Claims

1. an image carrier configured to be rotatable about a rotation axis and on whose surface an electrostatic latent image is formed; a developer container that contains a developer for developing the electrostatic latent image; a first electrode and a second electrode disposed opposite each other inside the developer accommodating portion; a first electrical contact electrically connected to the first electrode; a second electrical contact electrically connected to the second electrode; a first substrate electrically connected to the first electrical contact and configured to apply a voltage to the first electrical contact; a second substrate electrically connected to the second electrical contact, configured to detect a detection current flowing between the first electrode and the second electrode, and independent of the first substrate; a control unit that acquires a remaining amount of the developer contained in the developer container based on the detected current detected by the second substrate; Equipped with a shortest distance between the second substrate and the second electrical contact is shorter than a shortest distance between the first substrate and the second electrical contact; An image forming apparatus characterized in that, when the direction of the rotation axis and the direction perpendicular to the rotation axis are defined as a first direction and a second direction, respectively, and a direction perpendicular to both the first direction and the second direction is defined as a third direction, the distance between the second substrate and the second electrical contact is shorter than the distance between the first substrate and the second electrical contact in at least one of the first direction, the second direction, and the third direction.

2. 2. The image forming apparatus according to claim 1, wherein the distance between the second substrate and the second electrical contact is shorter than the distance between the first substrate and the second electrical contact in any of the first direction, the second direction, and the third direction.

3. 2. The image forming apparatus according to claim 1, wherein the distance between the second substrate and the second electrical contact in the direction of gravity is shorter than the distance between the first substrate and the second electrical contact.

4. 2. The image forming apparatus according to claim 1, wherein the second substrate has a first surface on which electronic components are provided and a second surface that is the reverse side of the first surface, and the second surface is arranged so as to face the second electrical contact.

5. 5. The image forming apparatus according to claim 4, wherein the electronic component is a component that constitutes a current detection circuit for detecting the detection current.

6. a connection member that electrically connects the second substrate and the first electrical contact; a protective member provided to cover the second surface of the second substrate while ensuring a space through which the connecting member passes; 5. The image forming apparatus according to claim 4, further comprising:

7. 2. The image forming apparatus according to claim 1, wherein the first electrical contact is electrically connected to the first substrate via the second substrate.

8. a supply member that supplies the toner contained in the developer container to the image carrier; 2. The image forming apparatus according to claim 1, wherein the first electrode supplies electricity to the supply member.

9. a supply member that supplies the toner contained in the developer container to the image carrier; 2. The image forming apparatus according to claim 1, wherein the first electrical contact receives power to be supplied to the supply member.

10. a device body on which the first substrate and the second substrate are provided; a cartridge provided with the image carrier, the developer container, the first electrical contact, and the second electrical contact, the cartridge being detachably attached to the main body of the apparatus; The image forming apparatus according to claim 1 , further comprising:

11. 11. The image forming apparatus according to claim 10, wherein the second substrate is disposed above the cartridge at a position overlapping the cartridge when viewed in the direction of gravity.

12. 12. The image forming apparatus according to claim 11, wherein the first substrate is disposed at a position where it does not overlap with the cartridge when viewed in the direction of gravity.

13. an apparatus main body in which the first substrate, the second substrate, and the image carrier are provided; a cartridge provided with the developer accommodating portion, the first electrical contact, and the second electrical contact, the cartridge being detachably attached to the main body of the apparatus; The image forming apparatus according to claim 1 , further comprising:

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