Developing device

Abstract

To provide an image forming apparatus that moves a developing unit provided with a plurality of electric loads including a developing memory between a developing position and a separation position, and to reduce reaction force of a cable that connects a developing device and the image forming apparatus to each other.SOLUTION: An image forming apparatus comprises: a first connector that is provided in the image forming apparatus, on the upstream side with respect to a mounting direction, and electrically connected with a power control section of the image forming apparatus via a first cable; a second connector that is provided in a developing unit, on the upstream side with respect to the mounting direction, and electrically connected with the first connector; and a third connector that is provided in the developing unit, and electrically connected with an electric connection section of a developing memory. The second connector is electrically connected with the developing memory via a second cable and the third connector, and an inductance sensor is electrically connected with the developing memory via a third cable. The second cable performs both power supply to the developing memory and the inductance sensor, and grounding.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus in which a developing unit is moved between a developing device and a spaced position. [Background technology]

[0002] There is an image forming apparatus in which a developing unit is replaceable independently of an image carrier unit. In this image forming apparatus, in order to determine the relative position of the developing unit mounted in the image forming apparatus with respect to the image carrier unit, the developing unit is moved between a developing position where the developing unit develops an electrostatic latent image formed on the image carrier and a separated position where the developing unit is separated from the developing position.

[0003] In an image forming apparatus that moves a developing unit between a developing device and a separated position, an inductance sensor and a sensor for detecting whether a developing unit installed in the image forming apparatus is new (hereinafter, referred to as a new product detection sensor) are provided in the developing unit. Patent Document 1 describes an image forming apparatus in which the cables of the inductance sensor and the new product detection sensor are integrated into a single connector on the developing unit side that connects to the image forming apparatus, and power can be supplied to both the inductance sensor and the new product detection sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-25666 Summary of the Invention [Problem to be solved by the invention]

[0005] If cables from each electrical load, such as an inductance sensor and a new product detection sensor, provided in the development unit are consolidated into one connector on the development unit side that connects to the image forming apparatus, the size of the connector becomes large, and restrictions on placement become more likely to occur. Also, in a configuration in which an electrical load, such as a storage device (development memory) as a new product detection sensor, is provided in the development unit, the number of cables increases compared to a configuration in which a fuse is provided in the development unit as a new product detection sensor, and restrictions on placement become greater. Also, as the number of cables connecting the image forming apparatus and the development unit increases, the bending stiffness (hereinafter referred to as stiffness) of the cables tends to increase.

[0006] In an image forming apparatus in which a developing unit is moved between a developing position and a separated position, the developing unit is generally pressed by an elastic member such as a spring, and the developing unit is moved from the separated position to the developing position. In such a configuration, if the pressing force of the developing unit is too large, there is a risk that the developing unit will be deformed, whereas if the pressing force of the developing unit is too small, there is a risk that the position of the developing unit cannot be guaranteed, resulting in poor development.

[0007] Therefore, the pressure of the developing unit is designed within a certain range, including the reaction force against the pressure force generated by the stiffness of the cable. On the other hand, the variation in stiffness is a factor in fluctuation of the pressure force, and the variation in the reaction force due to stiffness increases with an increase in the number of cables, so the risk of fluctuation in the pressure force of the developing unit increases, and the pressure force of the developing unit becomes unstable.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus that can reduce the reaction force of a cable connecting a developing device and the image forming apparatus in a configuration in which a developing unit provided with multiple electric loads such as developing memories is moved between a developing position and a separated position. [Means for solving the problem]

[0009] In order to achieve the above object, an image forming apparatus according to one aspect of the present invention has the following configuration: That is, an image forming apparatus including an image carrier unit including an image carrier, a developing unit that is mountable to the image forming apparatus and includes a developer carrier that carries a developer including toner and a carrier for developing an electrostatic latent image formed on the image carrier, a moving mechanism that moves the developing unit between a developing position where the electrostatic latent image formed on the image carrier is developed and a separated position that is separated from the developing position in order to determine a relative position of the developing unit mounted to the image forming apparatus with respect to the image carrier unit, an inductance sensor that is provided in the developing unit and detects a toner concentration in the developing unit, a development memory that is provided in the developing unit and stores predetermined information, and a developing unit that is provided in the image forming apparatus and detects a toner concentration in the developing unit. The image forming apparatus is provided with a first connector that is provided upstream in the mounting direction and electrically connected to a power control unit of the image forming apparatus via a first cable, a second connector that is provided in the developing unit and upstream in the mounting direction and electrically connected to the first connector, and a third connector that is provided in the developing unit and electrically connected to an electrical connection portion of the developing memory, wherein the second connector is electrically connected to the developing memory via the second cable and the third connector, and the inductance sensor is electrically connected to the developing memory via the third cable, and the second cable serves both as a power supply and an earth for the developing memory and the inductance sensor. Effect of the Invention

[0010] According to the present invention, in a configuration in which a development unit provided with multiple electrical loads such as development memories is moved between a development position and a separated position, the reaction force of the cable connecting the development device and the image forming device can be reduced. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment. [Diagram 2] 1 is a perspective view showing a configuration of an image forming apparatus according to a first embodiment. [Diagram 3] 1 is a cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment. [Diagram 5] 1 is a cross-sectional view illustrating a configuration of a developing device according to a first embodiment. [Figure 6] FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the first embodiment are necessarily essential to the solution of the present invention. The present invention can be implemented in various applications, such as printers, various printing machines, copiers, FAX machines, and multifunction machines.

[0013] [First embodiment] (Configuration of Image Forming Apparatus) First, the configuration of an image forming apparatus according to a first embodiment of the present invention will be described with reference to the cross-sectional view of Fig. 1. As shown in Fig. 1, an image forming apparatus 60 includes an endless intermediate transfer belt (ITB) 61 as an intermediate transfer body, and four image forming units 600 arranged from the upstream side to the downstream side along the rotation direction (the direction of the arrow Z in Fig. 1) of the intermediate transfer belt 61. Each of the image forming units 600 forms a toner image of each color, yellow (Y), magenta (M), cyan (C), and black (Bk).

[0014] The image forming section 600 includes an image carrier unit including a rotatable photoconductor drum 1 as an image carrier. The image forming section 600 also includes a charging roller 2 as a charging means, a developing device 3 as a developing means, a primary transfer roller 4 as a primary transfer means, and a photoconductor cleaner 5 as a photoconductor cleaning means, which are arranged along the rotation direction of the photoconductor drum 1.

[0015] Each of the developing devices 3 (developing units that develop the electrostatic latent image formed on the photosensitive drum 1) can be attached to and detached from the image forming device 60. Each of the developing devices 3 has a developer container 30 that contains a two-component developer (hereinafter simply referred to as developer) containing non-magnetic toner (hereinafter simply referred to as toner) and a magnetic carrier. In addition, each of the toner cartridges that contain toner of each color Y, M, C, and Bk is detachably attached to the image forming device 60. The toner of each color Y, M, C, and Bk is supplied to each of the developing devices 3 via a toner transport path.

[0016] The intermediate transfer belt 61 is stretched by a tension roller 6, a driven roller 7a, a primary transfer roller 4, a driven roller 7b, and a secondary transfer inner roller 66, and is driven to be transported in the direction of arrow Z in Fig. 1. The secondary transfer inner roller 66 also serves as a drive roller that drives the intermediate transfer belt 61. As the secondary transfer inner roller 66 rotates, the intermediate transfer belt 61 rotates in the direction of arrow Z in Fig. 1.

[0017] The intermediate transfer belt 61 is pressed by a primary transfer roller 4 from the back side of the intermediate transfer belt 61. In addition, by bringing the intermediate transfer belt 61 into contact with the photosensitive drum 1, a primary transfer nip portion serving as a primary transfer portion is formed between the photosensitive drum 1 and the intermediate transfer belt 61.

[0018] An intermediate transfer body cleaner 8 as a belt cleaning means is in contact with a position facing the tension roller 6 across the intermediate transfer belt 61. Also, a secondary transfer outer roller 67 as a secondary transfer means is disposed at a position facing the secondary transfer inner roller 66 across the intermediate transfer belt 61. The intermediate transfer belt 61 is sandwiched between the secondary transfer inner roller 66 and the secondary transfer outer roller 67. As a result, a secondary transfer nip portion as a secondary transfer portion is formed between the secondary transfer outer roller 67 and the intermediate transfer belt 61. In the secondary transfer nip portion, a predetermined pressure force and a transfer bias (electrostatic load bias) are applied to cause a toner image to adhere to the surface of the transfer material S (for example, paper, transparent film, etc.).

[0019] The transfer material S is stored in a stacked state in a transfer material storage section 62 (e.g., a feeding cassette or a feeding deck, etc.). The feeding means 63 feeds the transfer material S in accordance with the image formation timing, for example, using a friction separation method using a feeding roller or the like. The transfer material S sent out by the feeding means 63 is transported to a registration roller 65 arranged midway along a transport path 64. After skew correction and timing correction are performed by the registration roller 65, the transfer material S is transported to a secondary transfer nip section. In the secondary transfer nip section, the timing of the transfer material S and the toner image are matched, and secondary transfer is performed.

[0020] A fixing device 9 is disposed downstream of the secondary transfer nip portion in the transport direction of the transfer material S. The fixing device 9 applies a predetermined pressure and heat to the transfer material S transported to the fixing device 9, thereby melting and fixing a toner image on the surface of the transfer material S. The transfer material S with the image fixed in this manner is discharged directly to a discharge tray 601 by forward rotation of discharge rollers 69.

[0021] When double-sided image formation is performed, the discharge rollers 69 are rotated in the forward direction to transport the transfer material S until the rear end passes through the switching flapper 602, and then the discharge rollers 69 are rotated in the reverse direction. As a result, the transfer material S is transported to a double-sided transport path 603 with its leading and trailing ends switched. Thereafter, in time for the next image formation, the transfer material S is transported again to the transport path 64 by the re-feed rollers 604.

[0022] (Image formation process) During image formation, the photoconductor drum 1 is rotated by a motor. The charging roller 2 uniformly charges the surface of the photoconductor drum 1 that is being rotated. The exposure device 68 forms an electrostatic latent image on the surface of the photoconductor drum 1 that has been charged by the charging roller 2, based on a signal of image information input to the image forming device 60.

[0023] The developing device 3 (developing unit) has a rotatable developing sleeve 70 as a developer carrier that carries a developer. The developing device 3 develops an electrostatic latent image formed on the surface of the photoconductor drum 1 by the exposure device 68, using the developer carried on the surface of the developing sleeve 70. As a result, toner adheres to the exposed portion on the surface of the photoconductor drum 1, and a visible image is formed. A transfer bias (electrostatic load bias) is applied to the primary transfer roller 4, and the toner image formed on the surface of the photoconductor drum 1 is transferred onto the intermediate transfer belt 61. A small amount of toner (transfer residual toner) remaining on the surface of the photoconductor drum 1 after the primary transfer is collected by the photoconductor cleaner 5 and prepared for the next image forming process.

[0024] The image forming process of each color, which is processed in parallel by the image forming unit 600 of each color of Y, M, C, and Bk, is performed at a timing to sequentially superimpose the toner image of the upstream color that has been primarily transferred onto the intermediate transfer belt 61. As a result, a full-color toner image is formed on the intermediate transfer belt 61, and the toner image is conveyed to the secondary transfer nip portion. A transfer bias is applied to the secondary transfer outer roller 67, and the toner image formed on the intermediate transfer belt 61 is transferred to the transfer material S conveyed to the secondary transfer nip portion. A small amount of toner (transfer residual toner) remaining on the intermediate transfer belt 61 after the transfer material S has passed through the secondary transfer nip portion is collected by the intermediate transfer body cleaner 8. The fixing device 9 fixes the toner image transferred onto the transfer material S. The recording material S that has been subjected to the fixing process by the fixing device 9 is discharged to the discharge tray 601.

[0025] The series of image forming processes as described above is now complete, and the next image forming operation is prepared.

[0026] (Configuration of the developing device) Next, the configuration of the developing device 3 (developing unit) according to the first embodiment of the present invention will be described with reference to FIGS. 2, 3, 4 and 5. FIG.

[0027] The developing device 3 (developing unit) is configured to be replaceable independently of the photoconductor drum 1 (image carrier unit). One of the reasons for this is that, in line with the recent trend toward longer life spans for the entire image forming apparatus 60, the developing device 3 (developing unit) and the photoconductor drum 1 (image carrier unit) can be replaced separately due to the difference in life spans between them, thereby reducing the running costs of the product.

[0028] The developing device 3 (developing unit) and the photoconductor drum 1 (image carrier unit) can be replaced independently. For this purpose, the image forming apparatus 60 is provided with a moving mechanism that moves the developing unit between a developing position and a separated position in accordance with the opening and closing of a cover 611 of the image forming apparatus 60 and the opening and closing of an exchange door 610 of the developing unit or the image carrier unit. The developing position is a position where an electrostatic latent image formed on the image carrier is developed, and the separated position is a position separated from the developing position. The developing unit is moved between the developing position and the separated position by this moving mechanism, thereby determining the relative position of the developing unit installed in the image forming apparatus 60 with respect to the image carrier unit.

[0029] The moving mechanism is composed of elastic members such as springs, and is set so that even if an external force is applied to the developing device 3, the developing device 3 (developing unit) is pressed against the image carrier unit with a predetermined pressure.

[0030] The configuration of the moving mechanism provided in the image forming apparatus 60 will be described with reference to FIG. 2. FIG. 2 is a perspective view showing the configuration of the image forming apparatus 60 according to the first embodiment. As shown in FIG. 2, when the replacement door 610 is opened to replace the developing device 3 (developing unit) or the photoconductor drum 1 (image carrier unit), the developing device 3 (developing unit) is separated from the image carrier unit (the developing unit moves from the developing position to the separated position). By separating the developing device 3 (developing unit) from the image carrier unit, a certain distance is maintained between the units when they are pulled out from the image forming apparatus 60, and the photoconductor drum 1 or the developing sleeve 70 comes into contact with each other, reducing the possibility of damaging the surface of the photoconductor drum 1. Then, when the replacement door 610 is closed after the replacement of the developing device 3 (developing unit) or the image carrier unit is completed, the developing device 3 (developing unit) is pressed against and comes into contact with the image carrier unit (the developing unit moves from the separated position to the developing position).

[0031] In the first embodiment, as an example of a moving mechanism for moving the developing device 3 (developing unit) mounted in the image forming apparatus 60 between the developing position and the separated position, a configuration is adopted in which the developing unit is moved between the developing position and the separated position in conjunction with the opening and closing of the replacement door 610. Meanwhile, the means for moving the developing unit between the developing position and the separated position is not limited to this. For example, a configuration in which the developing unit is moved between the developing position and the separated position by a guide shape on the trajectory of insertion and removal of each unit may be used.

[0032] Here, the inserting / removing direction Gd (mounting direction) of the developing device 3 (developing unit) and the photoconductor drum 1 (image carrier unit) with respect to the image forming device 60 will be described with reference to FIG. 2 and FIG. 3. FIG. 3(A) and FIG. 3(B) are cross-sectional views showing the configuration of the image forming device 60 according to the first embodiment. The inserting / removing direction Gd of the developing device 3 (developing unit) and the image carrier unit with respect to the image forming device 60 is preferably set in the rotation axis direction rs of the photoconductor drum 1 and the developing sleeve 70. This is because in many image forming devices 60, the front side (near side) and the rear side (rear side) of the image forming device 60 are set in the rotation axis direction rs of the photoconductor drum 1 and the developing sleeve 70 due to the arrangement of each unit constituting the image forming device 60. In addition, a certain space is often reserved in front of the installation location of the image forming device 60 at the user's site for replacing a toner cartridge that contains toner to be replenished to the developing device 3. By setting the insertion / removal direction Gd of the developing device 3 (developing unit) and the photosensitive drum 1 to the rotational axis direction rs of the photosensitive drum 1 and the developing sleeve 70, the space can be shared with the replacement space for the toner cartridge, thereby reducing the space required for installing the image forming device 60.

[0033] Next, the details of the developing device 3 (developing unit) will be described with reference to Figures 4, 5, and 6. Figure 4 is a perspective view showing the configuration of the developing device 3 according to the first embodiment. Figure 5 is a cross-sectional view showing the configuration of the developing device 3 according to the first embodiment. Figure 6 is a perspective view showing the configuration of the developing device 3 according to the first embodiment.

[0034] The inside of the developing container 30 is partitioned into a developing chamber 31 as a first chamber and a stirring chamber 32 as a second chamber by a partition wall 38 extending in the vertical direction. The developing chamber 31 and the stirring chamber 32 are connected at both ends in the longitudinal direction via two communication parts 39 provided in the partition wall 38. Therefore, the developer can be communicated between the developing chamber 31 and the stirring chamber 32 via the communication parts 39. The developing chamber 31 and the stirring chamber 32 are arranged side by side in the horizontal direction. In this embodiment, the partition wall 38 is formed integrally with the developing container 30, but may be attached separately. The developing container 30 has an opening at a position corresponding to the developing area where the developing sleeve 70 faces the photosensitive drum 1. The developing sleeve 70 is rotatably arranged with respect to the developing container 30 so that a part of the developing sleeve 70 is exposed to the opening of the developing container 30.

[0035] A magnet roll 71 is fixedly disposed inside the developing sleeve 70, and serves as a magnetic field generating means having a plurality of magnetic poles along the rotation direction of the developing sleeve 70 and generating a magnetic field for carrying the developer on the surface of the developing sleeve 70. The developer in the developing chamber 31 is pumped up by the influence of the magnetic field caused by the magnetic poles of the magnet roll 71, and is supplied to the developing sleeve 70. Since the developer is supplied from the developing chamber 31 to the developing sleeve 70 in this manner, the developing chamber 31 is also called a supply chamber.

[0036] In the developing chamber 31, a first conveying screw 33 serving as a conveying means for stirring and conveying the developer in the developing chamber 31 is disposed opposite the developing sleeve 70. The first conveying screw 33 includes a rotating shaft 33a serving as a rotatable shaft portion, and a spiral blade portion 33b serving as a developer conveying portion provided along the outer periphery of the rotating shaft 33a, and is rotatably supported by the developing container 30. Bearing members are provided on both ends of the rotating shaft 33a.

[0037] Further, in the stirring chamber 32, a second conveying screw 34 is disposed as a conveying means for stirring the developer in the stirring chamber 32 and conveying the developer in the opposite direction to the first conveying screw 33. The second conveying screw 34 includes a rotating shaft 34a as a rotatable shaft portion and a spiral blade portion 34b as a developer conveying portion provided along the outer periphery of the rotating shaft 34a, and is rotatably supported by the developing container 30. Bearing members are provided on both ends of the rotating shaft 34a. The developer circulates between the developing chamber 31 and the stirring chamber 32 via a communication portion 39 as the first conveying screw 33 and the second conveying screw 34 are driven to rotate.

[0038] Next, the insertion / removal direction Gd of the developing device 3 (developing unit) and the arrangement of the toner supply port 41 will be described with reference to FIGS.

[0039] The developing device 3 needs to replenish the toner consumed by development within the developing device 3. The toner transport path 605a provided in the image forming device 60 and the toner supply port 41 of the developing device 3 are separated or connected when the developing device 3 (developing unit) is inserted into or removed from the image forming device 60. At this time, since a considerable amount of toner scatters from the connection part SA, it is preferable that the connection part SA is provided on the rear side of the image forming device 60 (downstream in the insertion direction Gd of the image forming device 60).

[0040] (Inductance sensor) Next, the arrangement of the inductance sensor 50 provided in the developing device 3 (developing unit) will be described with reference to FIGS.

[0041] The toner supplied to the developing device 3 through the toner supply port 41 must be thoroughly stirred and mixed with the magnetic carrier, and is therefore stirred by stirring members (screws 33, 34) provided within the developing device 3. The ratio of the stirred toner and carrier is measured by an inductance sensor 50 (toner concentration detection sensor) to judge the toner concentration in the developing unit and determine whether or not toner needs to be replenished. Therefore, if the toner and magnetic carrier are not thoroughly mixed, the toner concentration will not be uniform, making it difficult to correctly measure the toner concentration.

[0042] For this reason, since it is necessary to thoroughly mix the toner supplied from the toner supply port 41 with the magnetic carrier, it is preferable to place the inductance sensor 50 at a position as far away from the toner supply port 41 as possible.

[0043] However, if the inductance sensor 50 is located near the area where the developer is pumped up to the developing sleeve 70, the toner concentration will not be uniform due to toner consumption, etc. For this reason, it is appropriate to locate the inductance sensor 50 in a position as far away as possible from the toner supply port 41 and immediately before the developer is pumped up to the developing sleeve 70. When the inductance sensor 50 is located in such a position, the toner supply port 41 is located on the rear side of the image forming device 60 (downstream in the insertion direction Gd of the image forming device 60). For this reason, as shown in FIG. 4, the inductance sensor 50 is necessarily located near the front side of the image forming device 60 and the developing device 3 (upstream in the insertion direction Gd of the image forming device 60).

[0044] (Development memory) In the first embodiment, the developing device 3 (developing unit) is provided with a storage device (memory) as a new product detection sensor that detects whether the developing device 3 (developing unit) mounted on the image forming device 60 is new or not. The storage device (memory) as a new product detection sensor provided on the developing device 3 (developing unit) is hereinafter referred to as a developing memory 51. The developing memory 51 stores predetermined information for detecting whether the developing device 3 (developing unit) mounted on the image forming device 60 is new or not and individual information of the developing device 3. Here, the arrangement of the developing memory 51 will be described with reference to a perspective view (FIG. 6) showing the configuration of the developing device 3 according to the first embodiment.

[0045] The developing device 3 performs calibration of the inductance sensor 50 (initialization operation of the developing unit) based on the toner concentration at the time of manufacture. That is, when the developing device 3 (developing unit) is mounted on the image forming device 60, the developing memory 51 (new product detection sensor) detects whether the developing device 3 (developing unit) mounted on the image forming device 60 is new or not. Then, when the CPU of the image forming device 60 determines that the developing device 3 (developing unit) mounted on the image forming device 60 is new, the calibration of the inductance sensor 50 (initialization operation of the developing unit) is automatically performed.

[0046] (Electrical connection between inductance sensor and development memory) Next, the electrical connection between the inductance sensor 50 and the development memory 51 provided in the developing device 3 will be described with reference to FIG.

[0047] The image forming apparatus 60 has an electrical control unit that controls power and signals for the electrical loads of various units. In order to supply power to and communicate with the inductance sensor 50 and the development memory 51 provided in the developing apparatus 3, the developing apparatus 3 has an electrical connection portion 50a (connector) for connection to a cable 501 on the image forming apparatus main body side. The electrical connection portion (connector) on the image forming apparatus 60 side and the electrical connection portion 50a (connector) on the developing apparatus 3 side are male and female, respectively. For example, when the electrical connection portion (connector) on the image forming apparatus 60 side is male, the electrical connection portion 50a (connector) on the developing apparatus 3 side is female. Also, for example, when the electrical connection portion (connector) on the image forming apparatus 60 side is female, the electrical connection portion 50a (connector) on the developing apparatus 3 side is male.

[0048] Regarding the arrangement of the electrical connection part 50a (connector) on the developing device 3 side, it is also preferable to arrange the electrical connection part 50a on the upstream side in the insertion direction Gd of the image forming device 60. This is because, when the electrical connection part 50a on the developing device 3 side is arranged on the upstream side in the insertion direction Gd of the image forming device 60, the electrical path from the inductance sensor 50 to the electrical connection part 50a becomes shorter compared to when it is arranged on the downstream side in the insertion direction Gd of the image forming device 60. Similarly, it is preferable to arrange the developing memory 51 on the upstream side in the insertion direction Gd of the image forming device 60 from the viewpoint of the electrical path from the electrical connection part 50a. This is preferable from the viewpoint of not complicating the wiring of the cable and also from the viewpoint of miniaturizing the developing device 3 and reducing the risk of failure of the electrical path.

[0049] Also, the electrical connection part (connector) on the image forming device 60 side is electrically connected to the power control part of the image forming device 60 via a cable 501. In the insertion / removal direction Gd of the image forming device 60, it is assumed that the electrical connection part 50a is on the far side (downstream side in the insertion direction Gd of the image forming device 60). In this case, first, when inserting (attaching) the developing device 3 into the image forming device 60, the electrical connection part on the image forming device 60 side and the electrical connection part 50a on the developing device 3 side are electrically connected on the front side (upstream side in the insertion direction Gd) of the image forming device 60. Thereafter, it is necessary to further insert the developing device 3 in the insertion direction Gd until the developing device 3 is attached to the image forming device 60. At this time, the free length of the cable 501 connecting the power control part of the image forming device 60 and the electrical connection part on the image forming device 60 side must be made longer so that the electrical connection state between the electrical connection part on the image forming device 60 side and the electrical connection part 50a on the developing device 3 side is maintained. This makes it difficult to handle and store the excess length of the cable 501 (electrical cable) inside the image forming apparatus 60.

[0050] Therefore, in the first embodiment, in the insertion / removal direction Gd of the image forming device 60, the electrical connection portion 50a is disposed on the near side of the image forming device 60 (upstream side in the insertion direction Gd of the image forming device 60). Then, the developing device 3 is inserted into the image forming device 60, and just before the developing device 3 is attached to the image forming device 60, the electrical connection portion on the image forming device 60 side and the electrical connection portion 50a on the developing device 3 side are connected on the near side of the image forming device 60 (upstream side in the insertion direction Gd). This can reduce the risk that it becomes difficult to process or store the excess length of the cable 501 (electrical bundle) inside the image forming device 60.

[0051] It is assumed that the developing device 3 is inserted into the image forming device 60, and after the developing device 3 is attached to the image forming device 60, an attempt is made to connect the electrical connection part on the image forming device 60 side to the electrical connection part 50a on the developing device 3 side. In this case, it becomes difficult for a service person to access the electrical connection part 50a on the developing device 3 side. Therefore, as shown in Figures 3(A) and (B), it is preferable to insert the developing device 3 into the image forming device 60, and connect the electrical connection part on the image forming device 60 side to the electrical connection part 50a on the developing device 3 side just before the developing device 3 is attached to the image forming device 60.

[0052] As described above, since the inductance sensor 50 is disposed upstream in the insertion direction Gd of the image forming device 60, the electrical connection portion 50a (connector) on the developing device 3 side is disposed upstream in the insertion direction Gd of the image forming device 60. Accordingly, the developing memory 51 is also disposed on the front side (upstream in the insertion direction Gd of the image forming device 60).

[0053] A cable 503 connected to the electrical connection portion 50a is connected to an electrical connection portion 51a of the developing memory 51. A cable 502 to the inductance sensor 50 is also connected to the electrical connection portion 51a of the developing memory 51 in a centralized manner.

[0054] In this case, each cable (cables 501, 502, 503) is an assembly of multiple lines, such as ground, power, and signal lines, for each electrical load. Cable 503 is an assembly of signals, power, and ground lines for the development memory 51 and the inductance sensor 50. Cable 502 is an assembly of signal lines, power, and ground lines for the inductance sensor 50. The power and ground lines in cable 503 serve both as power supply and ground lines for the inductance sensor 50 and the development memory 51.

[0055] Suppose that the signal, power, and ground cables connected to the inductance sensor 50 and the developing memory 51 are each directly connected to the electrical connection portion 50a. In such a configuration, the number of pins of the connector increases in order to supply ground and power to the inductance sensor 50 and the developing memory 51, respectively. As a result, the number of cables in the cable 501 on the image forming apparatus main body side also increases.

[0056] As the number of cables connecting the image forming apparatus 60 and the developing device 3 increases, the bending stiffness (hereinafter referred to as stiffness) of the cables tends to increase. Furthermore, the stiffness of the cable 501 on the image forming apparatus main body side acts as an external force that inhibits the pressure force that presses the developing device 3 against the image carrier unit. Therefore, the pressure force of the developing device 3 is designed within a certain range, and is designed including the reaction force against the pressure force generated by the stiffness of the cable. On the other hand, variation in stiffness is a factor in fluctuation of the pressure force, and the variation in the reaction force due to stiffness increases with an increase in the number of cables, so there is a high risk of fluctuation in the pressure force of the developing device 3, and the pressure force of the developing device 3 becomes unstable.

[0057] Increasing the number of cables in cable 501 on the image forming apparatus main body side means that the external force that inhibits the pressure force increases, and in order to deal with this, it is necessary to set the spring force of the elastic member such as a spring provided in the movement mechanism to be large. It is also necessary to ensure appropriate rigidity in the movement mechanism that exerts a large spring force and the image carrier unit that receives the pressure force, and this may result in an increase in the size of the main body of image forming apparatus 60.

[0058] 6, in the first embodiment, the cable 502 of the inductance sensor 50 is connected to the electrical connection portion 51a of the developing memory 51. Furthermore, the cable extending from the electrical connection portion 51a of the developing memory 51 is connected to the electrical connection portion 50a (connector) on the developing device 3 side.

[0059] That is, the inductance sensor signal, the developing memory signal, the power, and the ground are once inputted from the electrical connection part 50a (connector) on the developing device 3 side to the developing memory 51 via a cable 503. Then, the inductance sensor signal, the power, and the ground are connected from there to the inductance sensor 50 via a cable 502 from the electrical connection part 51a of the developing memory 51.

[0060] In this way, by sharing the power and earth lines of the development memory 51 and the inductance sensor 50, it is possible to reduce the number of cables 503 connected to the electrical connection portion 50a (connector) on the side of the development device 3. In addition, since the number of cables 501 on the side of the image forming apparatus main body can also be reduced, it is possible to reduce the effect of the stiffness of the cables on the pressure force.

[0061] As described above, in the first embodiment, in a configuration in which a development unit provided with multiple electric loads such as a development memory is moved between a development position and a separation position, the reaction force of the cable connecting the development device and the image forming apparatus can be reduced. Therefore, according to the first embodiment, even in a configuration in which a development unit provided with multiple electric loads such as a development memory is moved between a development position and a separation position, the pressure force of the development unit can be stabilized.

[0062] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications (including organic combinations of the respective embodiments) are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0063] In the above embodiment, as shown in Fig. 1, the image forming device 60 performs primary transfer of the toner images carried on each of the photosensitive drums 1 onto the intermediate transfer belt 61. After that, the image forming device 60 brings the transfer material S into contact with the intermediate transfer belt 61 and performs secondary transfer of the toner images carried on the intermediate transfer belt 61 onto the transfer material S. In the above embodiment, the image forming device 60 configured as described above has been described as an example, but is not limited to this. It is also possible to apply the present invention to an image forming device configured to bring the transfer material S into direct contact with the photosensitive drum 1 and directly transfer the toner images carried on the photosensitive drum 1 onto the transfer material S. [Explanation of symbols]

[0064] 1 Photoconductor drum 3. Developing device 50 Inductance Sensor 50a Electrical connections (connectors) 51 Development memory 60 Image forming device 70 Developing sleeve 501 Cable 502 Cable 503 Cable

Claims

1. An image forming apparatus, an image carrier unit including an image carrier; a developing unit that is mountable to the image forming apparatus and includes a developer carrier that carries a developer containing toner and a carrier for developing an electrostatic latent image formed on the image carrier; a moving mechanism that moves the developing unit between a developing position where the developing unit develops an electrostatic latent image formed on the image carrier and a spaced position away from the developing position in order to determine a relative position of the developing unit with respect to the image carrier unit when the developing unit is mounted on the image forming apparatus; an inductance sensor provided in the developing unit for detecting a toner concentration in the developing unit; a development memory provided in the development unit and storing predetermined information; a first connector that is provided in the image forming apparatus, is provided upstream in a mounting direction in which the developing unit is mounted in the image forming apparatus, and is electrically connected to a power control unit of the image forming apparatus via a first cable; a second connector provided in the developing unit, provided upstream in the mounting direction, and electrically connected to the first connector; a third connector provided in the developing unit and electrically connected to an electrical connection portion of the developing memory; Equipped with the second connector is electrically connected to the developing memory via a second cable and the third connector, and the inductance sensor is electrically connected to the developing memory via the third cable; The second cable serves both as a power supply and a ground for the developing memory and the inductance sensor.

1. An image forming apparatus comprising:

2. The predetermined information is information for detecting whether the developing unit is new or not.

2. The image forming apparatus according to claim 1,

3. The developing memory is provided on the upstream side in the mounting direction.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

4. The developing memory is provided upstream of the inductance sensor in the mounting direction.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. a door that opens and closes to replace the developing unit; The moving mechanism moves the developing unit between the developing position and the separated position in association with opening and closing of the door.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

Images