JP7527881B2 - Developing device - Google Patents

Description

The present invention relates to a developing device.

There is a process cartridge in which a developing unit that develops an electrostatic latent image formed on an image carrier and an image carrier unit that includes an image carrier are integrated into a cartridge. A configuration is known in which the process cartridge is provided with electrical contacts, and when the process cartridge is mounted in an image forming device, the electrical contacts on the cartridge side are electrically connected to the electrical contacts on the image forming device side (see Patent Document 1).

There is also a known developing device that is equipped with an inductance sensor that detects the toner concentration in the developing container and a new product detection sensor that detects whether the developing device is new or not (see Patent Document 2).

JP 2011-39541 A JP 2019-197238 A

There is an image forming device in which the developing unit can be replaced independently of the image carrier unit. In this image forming device, in order to determine the relative position of the developing unit installed in the image forming device with respect to the image carrier unit, the developing unit is moved between a developing position where the electrostatic latent image formed on the image carrier is developed and a separated position where the developing unit is separated from the developing position.

In an image forming device that moves a development unit from a separated position to a development position, an inductance sensor and a new product detection sensor are provided on the development unit, and electrical contacts for supplying power to the inductance sensor and the new product detection sensor are provided on the development unit. In this case, it is necessary to increase the size of the electrical contacts on the development unit side or the image forming device side so that the electrical contacts on the development unit side and the electrical contacts on the image forming device side are in stable contact when the development unit moves from the separated position to the development position, which places restrictions on the arrangement of the electrical contacts.

On the other hand, in an image forming device that moves a development unit from a separated position to a development position, a connector for supplying power to the inductance sensor and a connector for supplying power to the new product detection sensor are provided on the development unit. In addition, a configuration is adopted in which the connector for supplying power to the inductance sensor is electrically connected to the image forming device via a first cable, and the connector for supplying power to the new product detection sensor is electrically connected to the image forming device via a cable. When such a configuration is adopted, multiple connectors are provided on the development unit to supply power to each of the inductance sensor and the new product detection sensor, resulting in a large number of parts.

The present invention has been made in consideration of the above problems. The object of the present invention is to provide a development device that is capable of supplying power to both the inductance sensor and the new product detection sensor with a simple configuration.

In order to achieve the above object, a developing device according to one aspect of the present invention has the following configuration. That is, the developing device is mountable to an image forming apparatus, and has a developer carrier that carries a developer containing toner and a carrier to develop an electrostatic latent image formed on an image carrier, a first chamber that supplies the developer to the developer carrier, a second chamber that is partitioned from the first chamber by a partition wall, a first communication portion that allows the developer to communicate from the second chamber to the first chamber, and a second communication portion that allows the developer to communicate from the first chamber to the second chamber, and includes a developing container that contains the developer, a first conveying screw that is disposed in the first chamber and conveys the developer in a first direction from the first communication portion toward the second communication portion, a second conveying screw that is disposed in the second chamber and conveys the developer in a second direction opposite to the first direction, and a developing container that is disposed in the second chamber and conveys the developer in a second direction opposite to the first direction. The toner concentration of the developer stored in the developing device is detected by an inductance sensor, a new product detection sensor detects whether the developing device is new, and a connector that can be electrically connected to the electrical connection part of the image forming device via a first cable, and the inductance sensor is disposed downstream in the second direction and upstream in the mounting direction in which the developing device is mounted to the image forming device, and the new product detection sensor is disposed upstream of the inductance sensor and downstream of the connector with respect to the mounting direction, and the connector is electrically connected to the inductance sensor via a second cable and electrically connected to the new product detection sensor via a third cable.

According to the present invention, it is possible to supply power to both the inductance sensor and the new product detection sensor with a simple configuration.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to a first embodiment. 1 is a perspective view illustrating a configuration of an image forming apparatus according to a first embodiment. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to a first embodiment. FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment. 1 is a cross-sectional view illustrating a configuration of a developing device according to a first embodiment. FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment.

The following describes in detail an embodiment of the present invention with reference to the accompanying drawings. Note that the following embodiment does 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 a variety of applications, including printers, various printing machines, copiers, fax machines, and multifunction machines.

[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 C 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).

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.

Each of the developing devices 3 (developing units that develop the electrostatic latent image formed on the photosensitive drum 1) can be attached to the image forming device 60, and can also be detached from the image forming device 60. Each of the developing devices 3 has a developing container 30 that contains a two-component developer (hereinafter simply referred to as developer) that contains 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 can be attached to and detached from 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.

The intermediate transfer belt 61 is tensioned 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 C 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 C in FIG. 1.

The intermediate transfer belt 61 is pressed by the 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.

An intermediate transfer body cleaner 8 as a belt cleaning means is in contact with the tension roller 6 across the intermediate transfer belt 61. In addition, a secondary transfer outer roller 67 as a secondary transfer means is disposed in 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 (e.g., paper, transparent film, etc.).

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.

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

When forming a double-sided image, 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. This switches the leading and trailing ends of the transfer material S and transports it to the double-sided transport path 603. Then, 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.

(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.

The developing device 3 (developing unit) has a rotatable developing sleeve 70 as a developer carrier that carries the developer. The developing device 3 uses the developer carried on the surface of the developing sleeve 70 to develop the electrostatic latent image formed on the surface of the photosensitive drum 1 by the exposure device 68. As a result, toner adheres to the exposed portion on the surface of the photosensitive 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 photosensitive drum 1 is transferred onto the intermediate transfer belt 61. The small amount of toner remaining on the surface of the photosensitive drum 1 after the primary transfer (transfer residual toner) is collected by the photosensitive cleaner 5 and prepared for the next image creation process.

The image forming process for each color, which is processed in parallel by the image forming unit 600 for each color of Y, M, C, and Bk, is performed at a timing that sequentially superimposes 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 transported 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 transported to the secondary transfer nip portion. The toner (transfer residual toner) remaining slightly on the intermediate transfer belt 61 after the transfer material S passes 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.

The series of image formation processes described above is now complete, and the machine is ready for the next image formation operation.

(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.

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 overall life spans for image forming devices 60, the developing device 3 (developing unit) and the photoconductor drum 1 (image carrier unit) can be replaced separately due to differences in their life spans, thereby reducing the running costs of the product.

The developing device 3 (developing unit) and the photoconductor drum 1 (image carrier unit) can be replaced independently. To this end, the image forming device 60 is provided with a movement mechanism that moves the developing unit between the developing position and the separated position in response to the opening and closing of the cover 611 of the image forming device 60 and the opening and closing of the replacement door 610 of the developing unit and the image carrier unit. The developing position is the position where the electrostatic latent image formed on the image carrier is developed, and the separated position is the position separated from the developing position. The relative position of the developing unit installed in the image forming device 60 to the image carrier unit is determined by moving the developing unit between the developing position and the separated position using this movement mechanism.

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 of 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).

In the first embodiment, as an example of a moving mechanism for moving the developing device 3 (developing unit) attached to the image forming device 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. On the other hand, the means for moving the developing unit between the developing position and the separated position is not limited to this. For example, the developing unit may be moved between the developing position and the separated position by a guide shape on the trajectory of insertion and removal of each unit.

Here, the insertion/removal direction Gd 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 FIGS. 2 and 3. FIGS. 3A and 3B are cross-sectional views showing the configuration of the image forming device 60 according to the first embodiment. It is preferable that the insertion/removal direction Gd of the developing device 3 (developing unit) and the image carrier unit with respect to the image forming device 60 is 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 the toner cartridge that contains the 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 rotation 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, and the space required for installing the image forming device 60 can be reduced.

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. Figures 6 (A) and (B) are perspective views showing the configuration of the developing device 3 according to the first embodiment.

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 of 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 it may be attached separately. The developing container 30 has an opening at a position corresponding to the development 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.

A magnet roll 71 is fixedly disposed inside the developing sleeve 70, and has multiple magnetic poles along the direction of rotation of the developing sleeve 70. The magnet roll 71 acts as a magnetic field generating means that generates a magnetic field for carrying 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.

In the developing chamber 31, a first transport screw 33 serving as a transport means for stirring and transporting the developer in the developing chamber 31 is disposed opposite the developing sleeve 70. The first transport screw 33 includes a rotating shaft 33a serving as a rotatable shaft portion, and a spiral blade portion 33b serving as a developer transport 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.

In addition, a second conveying screw 34 is disposed in the stirring chamber 32 as a conveying means for stirring the developer in the stirring chamber 32 and conveying it 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 the communication portion 39 as the first conveying screw 33 and the second conveying screw 34 are driven to rotate.

Next, the insertion/removal direction Gd of the developing device 3 (developing unit) and the arrangement of the toner supply port 41 will be explained using Figures 3 and 4.

The developing device 3 needs to replenish the toner consumed by development. 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, a considerable amount of toner scatters from the connection part S-A, so it is preferable that the connection part S-A is provided at the back side of the image forming device 60 (downstream in the insertion direction Gd of the image forming device 60).

(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.

The toner supplied to the developing device 3 through the toner supply port 41 must be thoroughly stirred and mixed with the magnetic carrier, so it is stirred by stirring members (screws 33, 34) provided within the developing device 3. The ratio of the stirred toner to carrier is measured by an inductance sensor 50 (toner concentration detection sensor) to determine the toner concentration in the developing unit and 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.

For this reason, it is necessary to thoroughly mix the toner supplied through the toner supply port 41 with the magnetic carrier, so it is preferable to position the inductance sensor 50 as far away as possible from the toner supply port 41.

However, if the inductance sensor 50 is placed 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 place the inductance sensor 50 as far away as possible from the toner supply port 41 and just before the developer is pumped up to the developing sleeve 70. If the inductance sensor 50 is placed in such a position, the toner supply port 41 will be placed 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 will inevitably be placed 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).

In the first embodiment, the image forming device 60 has a power control unit that controls the power to various units. In the first embodiment, the inductance sensor 50 provided in the developing device 3 (developing unit) is arranged upstream of the insertion direction Gd of the image forming device 60. In the first embodiment, the developing device 3 (developing unit) has an electrical connection portion 50a (connector) for supplying power to the inductance sensor 50. The electrical connection portion 50a (connector) for supplying power to the inductance sensor 50 is electrically connected to an electrical connection portion (connector) on the image forming device 60 side that is electrically connected to the power control portion of the image forming device 60 via a cable 501. The electrical connection portion (connector) on the image forming device 60 side and the electrical connection portion (connector) on the developing device 3 side are in a male-female relationship. For example, when the electrical connection portion (connector) on the image forming device 60 side is in a male relationship, the electrical connection portion (connector) on the developing device 3 side is in a female relationship. Also, for example, if the electrical connection part (connector) on the image forming device 60 side is a female connection, the electrical connection part (connector) on the development device 3 side is a male connection.

When arranging the electrical connection part 50a (connector) on the developing device 3 (developing unit), it is preferable to arrange the electrical connection part 50a upstream 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 upstream 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 is shorter than when it is arranged downstream in the insertion direction Gd of the image forming device 60. The shorter the electrical path from the inductance sensor 50 to the electrical connection part 50a, the shorter the length of the cable 502 that electrically connects the inductance sensor 50 and the electrical connection part 50a. For this reason, this is preferable from the viewpoint of not complicating the cable routing and also from the viewpoint of miniaturizing the developing device 3 and reducing the risk of failure of the electrical path.

In addition, 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 at the back side (downstream side of 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 at the front side (upstream side of the insertion direction Gd) of the image forming device 60. After that, 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 increased 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 bundle) inside the image forming device 60.

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 reduces the risk that it will be difficult to process or store the excess length of the cable 501 (electrical bundle) within the image forming device 60.

Let us say 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, the serviceman attempts 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 the serviceman 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. As described above, the inductance sensor 50 is disposed upstream of the image forming device 60 in the insertion direction Gd, and therefore the electrical connection part 50a electrically connected to the inductance sensor 50 via the cable 502 is disposed upstream of the image forming device 60 in the insertion direction Gd.

(New product detection sensor)
Next, the arrangement of the new product detection sensor 51 that detects whether the developing device 3 (developing unit) installed in the image forming apparatus 60 is new or not will be described with reference to Figures 5 and 6. Note that in Figure 4, the new product detection sensor 51, the cable 502 that connects the electrical connection portion 50a (connector) and the inductance sensor 50, and the cable 503 that connects the electrical connection portion 50a (connector) and the new product detection sensor 51 are omitted.

The developing device 3 calibrates the inductance sensor 50 (initialization 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 new product detection sensor 51 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 inductance sensor 50 is automatically calibrated (initialization of the developing unit). The new product detection sensor 51 may be any device that can detect that the developing device 3 has been replaced, and the means for detecting this may be a memory function (memory) or a fuse.

The new product detection sensor 51 provided in the developing device 3 must be electrically connected to the electrical connection portion 50a on the developing device 3 side via the cable 503. As described above, the electrical connection portion 50a on the developing device 3 side is provided upstream of the insertion direction Gd of the image forming device 60 (front side of the image forming device 60). For this reason, it is preferable to place the new product detection sensor 51 upstream of the insertion direction Gd of the image forming device 60 (front side of the image forming device 60) for the same reasons as the inductance sensor 50.

Based on the detection signal of the new product detection sensor 51, the CPU of the image forming device 60 judges whether the developing device 3 installed in the image forming device 60 is new or old (durable product). There are various methods for judging whether the developing device 3 installed in the image forming device 60 is new or old, and any method may be used. In the first embodiment, the developing device 3 is provided with a fuse, and when power is supplied to the new product detection sensor 51, a predetermined current flows through the fuse provided in the developing device 3 and the fuse is cut, so that the CPU of the image forming device 60 can judge that the developing device 3 is new. On the other hand, in the case of an old developing device 3, the fuse has already been cut and no current flows, so that the CPU of the image forming device 60 can judge that the developing device 3 is old.

In the first embodiment, both the inductance 50 and the new product detection sensor 51 are arranged upstream of the insertion direction Gd of the image forming device 60 (the front side of the image forming device 60). Also, in the first embodiment, the new product detection sensor 51 is arranged upstream of the inductance sensor 50 in the insertion direction Gd of the image forming device 60 (the direction in which the developing device 3 is attached to the image forming device 60). This is because the position at which the inductance sensor 50 is arranged is determined in advance from the viewpoint of improving the detection accuracy of the toner concentration in the developing container 30. For this reason, the new product detection sensor 51 should be arranged in a position that does not interfere with the inductance sensor 50 in the insertion direction Gd, and is preferably arranged upstream of the inductance sensor 50 in the insertion direction Gd from the viewpoint of accessibility for service personnel.

Let us assume that in an image forming device 60 that moves the developing device 3 (developing unit) from the separated position to the developing position, a connector for supplying power to the inductance sensor 50 and a connector for supplying power to the new product detection sensor 51 are provided on the developing unit. In addition, let us assume that a configuration is adopted in which the connector for supplying power to the inductance sensor 50 is connected to the image forming device 60 via a cable 502, and the connector for supplying power to the new product detection sensor 51 is connected to the image forming device 60 via a cable 503. When such a configuration is adopted, multiple connectors are provided on the developing device 3 (developing unit) to supply power to each of the inductance sensor 50 and the new product detection sensor 51, resulting in a large number of parts.

Therefore, in the first embodiment, the electrical connection portion 50a (connector) of the new product detection sensor 51 and the electrical connection portion (connector) of the inductance sensor 50 are integrated into the same connection portion. That is, the electrical connection portion 50a serves as both the electrical connection portion (connector) of the new product detection sensor 51 and the electrical connection portion (connector) of the inductance sensor 50. The electrical connection portion 50a (connector) provided in the developing device 3 (developing unit) is electrically connected to the new product detection sensor 51 via a cable 503. The electrical connection portion 50a (connector) provided in the developing device 3 (developing unit) is also electrically connected to the inductance sensor 50 via a cable 502.

The electrical connection portion 50a serves as both the electrical connection portion (connector) for the new product detection sensor 51 and the electrical connection portion (connector) for the inductance sensor 50. This allows the service technician to supply power to the inductance sensor 50 and also to supply power to the new product detection sensor 51 by simply electrically connecting the electrical connection portion (connector) on the image forming device 60 side to the electrical connection portion 50a (connector) on the developing device 3 side.

Suppose that the connector for supplying power to the inductance sensor 50 and the connector for supplying power to the new product detection sensor 51 are separate. In this case, the service technician performs the work of electrically connecting the connector on the image forming device 60 side and the electrical connection part (connector) of the new product detection sensor 51 in order to supply power to the inductance sensor 50. In addition, the service technician must perform the work of electrically connecting the connector on the image forming device 60 side and the electrical connection part (connector) of the inductance sensor 50. On the other hand, according to the invention of the first embodiment, in order to supply power to the inductance sensor 50 and to supply power to the new product detection sensor 51, it is only necessary to electrically connect the electrical connection part (connector) on the image forming device 60 side and the electrical connection part 50a on the developing device 3 side.

As shown in Figures 3A and 3B, the serviceman needs to insert the developing device 3 in the insertion direction Gd of the image forming device 60 even after electrically connecting the connector on the image forming device 60 side and the electrical connection part 50a (connector) on the developing device 3 side. This is because, as described above, 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, the serviceman tries 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 the serviceman to access the electrical connection part 50a on the developing device 3 side. Therefore, 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 on the front side of the image forming device 60 (upstream side in the insertion direction Gd) just before the developing device 3 is attached to the image forming device 60.

Even if the developing device 3 is inserted in the insertion direction Gd of the image forming device 60 after electrically connecting the connector on the image forming device 60 side with the electrical connection part 50a on the developing device 3 side, it is necessary to prevent the connection between the connector on the image forming device 60 side and the electrical connection part 50a from being disconnected. For this reason, it is necessary to set the length of play (free length) of the cable 501 that connects the power control part of the image forming device 60 and the connector on the image forming device 60 side. Therefore, in the first embodiment, the length of play (free length) of the cable 501 is set to 20 mm or more and 80 mm or less, taking into consideration that the developing device 3 is moved in the insertion/removal direction Gd after connecting the cable 501 on the image forming device 60 side to the connector on the developing device 3 side. If the length of play (free length) of the cable 501 is less than 20 mm, it becomes difficult for a serviceman to pinch the connector on the image forming device 60 side and connect it to the developing device 3. On the other hand, if the length of slack (free length) of cable 501 is longer than 80 mm, it is necessary to control the position of cable 501 so that cable 501 does not get caught when storing cable 501 inside image forming device 60. Therefore, in the examples of Figures 6 (A) and (B), the length of slack (free length) of cable 501 is set to 50 mm.

In the first embodiment, the electrical connection portion 50a is electrically connected to the inductance sensor 50 via a cable 502, and is also electrically connected to the new product detection sensor 51 via a cable 503. As shown in FIGS. 6(A) and 6(B), the cables 502 and 503 are routed with a portion of the cable 502 and a portion of the cable 503 bundled with insulating tape 504. This makes it easier to route the cables 502 and 503.

Next, a more preferable arrangement of the new product detection sensor 51 will be described with reference to FIG. 5. In recent years, there has been a demand for miniaturization of the main body size of the image forming apparatus 60, and therefore, there is a demand for improving the arrangement density of the developing device 3 and the image carrier unit. The developing device 3 is provided with stirring members (screws 33 and 34). For this reason, the developing container 30 is often formed with curved shapes R1 and R2 that follow the outer shapes of the screws 33 and 34. A space DS is formed in the area surrounded by the curved shapes R1 and R2 that follow the outer shapes of the screws 33 and 34 and the tangent line L that touches R1 and R2. By arranging the new product detection sensor 51 in the space DS, the protrusion of the new product detection sensor 51 from the developing device 3 is suppressed, and the developing device 3 can be made smaller.

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.

In the above embodiment, as shown in FIG. 1, the image forming device 60 performs a 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 to perform a 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 image carried on the photosensitive drum 1 onto the transfer material S.

REFERENCE SIGNS LIST 1 photoconductor drum 3 developing device 50a electrical connection portion 50 inductance sensor 51 new product detection sensor 60 image forming device 70 developing sleeve 501 cable 502 cable 503 cable

Claims (3)

A developing device that can be attached to an image forming apparatus,
a developer carrier that carries a developer containing toner and a carrier for developing an electrostatic latent image formed on the image carrier;
a developing container having a first chamber for supplying the developer to the developer carrier, a second chamber partitioned from the first chamber by a partition wall, a first communication portion for allowing the developer to communicate from the second chamber to the first chamber, and a second communication portion for allowing the developer to communicate from the first chamber to the second chamber, and containing the developer;
a first conveying screw disposed in the first chamber and configured to convey the developer in a first direction from the first communicating portion toward the second communicating portion;
a second conveying screw disposed in the second chamber and configured to convey the developer in a second direction opposite to the first direction;
an inductance sensor disposed in the second chamber for detecting a toner concentration of the developer contained in the developing container;
a new product detection sensor for detecting whether the developing device is new;
a connector that is electrically connectable to an electrical connection portion of the image forming apparatus via a first cable;
Equipped with
the inductance sensor is disposed downstream in the second direction and upstream in a mounting direction in which the developing device is mounted in the image forming apparatus,
With respect to the mounting direction, the new product detection sensor is disposed upstream of the inductance sensor and downstream of the connector,
the connector is electrically connected to the inductance sensor via a second cable, and is electrically connected to the new product detection sensor via a third cable. 2. The developing device according to claim 1, wherein the connector is electrically connected to the inductance sensor via the second cable with a portion of the second cable and a portion of the third cable bundled together with insulating tape, and is electrically connected to the new product detection sensor via the third cable. The developer carrier is rotatable,
The new product detection sensor is a fuse,
When the developing device is viewed in a cross section perpendicular to the rotation axis of the developer carrier,
3. The developing device according to claim 1, wherein the fuse is disposed on a bottom surface side of the developing container, in an area between a rotation center of the first conveying screw and a rotation center of the second conveying screw.

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