Patent Application
20250053131
The present disclosure relates to an image forming apparatus, such as a multifunctional peripheral having a plurality of functions of a copier, a printer, and a facsimile.
As an image forming apparatus, there has been a well-known configuration for forming a toner image by using a two-component developer including a non-magnetic toner and a magnetic carrier. In the configuration, an electrostatic latent image on a photosensitive drum is normally developed using the toner as the toner image in a development step, and particles as the carrier also adhere to the photosensitive drum at a certain percentage in some cases (carrier adhesion). The occurrence of carrier adhesion affects the output image. United States Patent Application Publication No. 2020/0292967, for example, discusses a configuration including a carrier collection device that collects carrier particles adhering to the photosensitive drum.
The carrier collection device discussed in United States Patent Application Publication No. 2020/0292967 includes a collection roller and a magnet roller provided in the collection roller, and applies the voltage obtained by superimposing an alternating-current voltage on a direct-current voltage to the collection roller. With the configuration, carrier particles on the photosensitive drum are collected to the collection roller by a magnetic force with the magnet roller and an electrostatic force with the application voltage. When the carrier collection device collects carrier particles in the above-described manner, the toner can also be partially collected to the collection roller. Thus, in the configuration discussed in United States Patent Application Publication No. 2020/0292967, a toner removal mode is performed during a non-image formation. In the toner removal mode, while the photosensitive drum rotates at a lower speed than during the image formation, an alternating-current voltage is applied to the collection roller, returning toner adhering to the collection roller to the photosensitive drum.
The reduction of the rotation speed of the photosensitive drum in the toner removal mode as in the configuration discussed in United States Patent Application Publication No. 2020/0292967 involves changing the rotation speeds of the photosensitive drum between during the image formation and the toner removal mode. The toner removal mode cannot be performed during the image formation, which involves taking some time for the toner removal mode to be performed. This, however, increases the downtime in which no image formation can be performed. On the other hand, if the toner removal mode is performed without lowering the rotation speed of the photosensitive drum, that case involves taking a longer time of the toner removal mode for a sufficient removal of the toner adhering to the collection roller, which also results in an increase of the downtime.
The present disclosure is directed to a technique providing an improved efficiency for removing toner on a collection roller while reducing the downtime.
According to an aspect of the present disclosure, an image forming apparatus configured to perform an image forming operation, the image forming apparatus includes a rotatable image carrying member on which an electrostatic latent image is formed, a developing device including a developer carrying member, the developing device being configured to contain a developer including toner and carrier, the developer carrying member being configured to carry the developer for developing the electrostatic latent image formed on the image carrying member into a toner image, a transfer member to which the toner image carried by the image carrying member is transferred, a carrier collection device including a rotatable collection roller, a magnet, and a conductor member, the carrier collection device being configured to collect the carrier from the image carrying member, the collection roller being disposed facing the image carrying member, downstream of a development portion where the electrostatic latent image formed on the image carrying member is developed, and upstream of a transfer portion where the toner image carried by the image carrying member is transferred to the transfer member in a rotation direction of the image carrying member, the magnet being non-rotatably disposed inside the collection roller, the conductor member being disposed facing the collection roller, a first bias application unit configured to apply a first bias obtained by superimposing a direct-current voltage and an alternating-current voltage, to the collection roller, and a second bias application unit configured to apply a second bias including the direct-current voltage, to the conductor member, wherein, during the image forming operation, an alternating-current electric field is formed between the collection roller to which the first bias is applied and the conductor member to which the second bias is applied.
According to another aspect of the present disclosure, an image forming apparatus configured to perform an image forming operation, the image forming apparatus includes a rotatable image carrying member on which an electrostatic latent image is formed, a developing device including a developer carrying member, the developing device being configured to contain a developer including toner and carrier, the developer carrying member being configured to carry the developer for developing the electrostatic latent image formed on the image carrying member into a toner image, a transfer member to which the toner image carried by the image carrying member is transferred, a carrier collection device including a rotatable collection roller, a magnet, and a conductor member, the carrier collection device being configured to collect the carrier from the image carrying member, the collection roller being disposed facing the image carrying member, downstream of a development portion where the electrostatic latent image formed on the image carrying member is developed, and upstream of a transfer portion where the toner image carried by the image carrying member is transferred to the transfer member in a rotation direction of the image carrying member, the magnet being non-rotatably disposed inside the collection roller, the conductor member being disposed facing the collection roller; and a bias application unit configured to apply a bias obtained by superimposing a direct-current voltage and an alternating-current voltage, to the collection roller, wherein the conductor member is grounded, and wherein, during the image forming operation, an alternating-current electric field is formed between the collection roller to which the bias is applied and the conductor member.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An exemplary embodiment will now be described with reference to
The image forming apparatus 100 according to the present exemplary embodiment is a full-color image forming apparatus 100 with an electrophotographic system, and includes four image forming units Pa, Pb, Pc, and Pd. Each of the image forming units has substantially the same configuration except for the different developing colors. In the following, unless a discrimination is stated, the image forming unit Pa is described as a representative, and suffixes b, c, and d that indicate configurations of the respective other image forming units are each appended to the corresponding image forming unit of the other image forming units, and the detailed description will be omitted.
The image forming unit Pa includes a photosensitive drum 1a as an image carrying member that carries an electrostatic latent image on its surface. The photosensitive drum 1a is an example of an electrophotographic photosensitive body, and has a cylindrical shape. The photosensitive drum 1a rotates in the arrow direction (counterclockwise direction) in
An entire sequence of image forming in the image forming apparatus 100 having the above-described configuration will be described.
First, the surface of the photosensitive drum 1a is uniformly charged to a predetermined charged potential by the charger 2a. The photosensitive drum 1a charged by the charger 2a is scanned with and exposed to laser beams modulated based on image signals, from the laser beam scanner 3a as an example of an exposure device.
The laser beam scanner 3a is controlled based on input image data, and image data for emitting laser beams is input from an external terminal, such as a document reader and a personal computer (PC). The surface potential of the photosensitive drum 1a charged by the charger 2a is changed at image portions by laser beams from the laser scanner 3a, and an electrostatic latent image is formed on the photosensitive drum 1a.
The electrostatic latent image formed on the photosensitive drum 1a in the above-described manner is reversely developed with toner by the developing device 4a, into a visible image, or a toner image. In the present exemplary embodiment, the developing device 4a uses a two-component development system using a developer including a non-magnetic toner and a magnetic carrier. In other words, each of the developing devices 4a, 4b, 4c, and 4d stores a two-component developer including a toner for its corresponding color. More specifically, the developing device 4a stores yellow (Y) toner, the developing device 4b stores magenta (M) toner, the developing device 4c stores cyan (C) toner, and the developing device 4d stores black (K) toner. Accordingly, when the above-described step is performed by each of the image forming units Pa, Pb, Pc, and Pd, toner images in four colors, yellow, magenta, cyan, and black, are formed on photosensitive drums 1a, 1b, 1c, and 1d, respectively.
An intermediate transfer belt 60 as an intermediate transfer member is disposed below the image forming units Pa, Pb, Pc, and Pd. The intermediate transfer belt 60 is stretched over rollers 61, 62, and 63, and is movable in the arrow direction. A secondary transfer roller 64 is disposed outside the intermediate transfer belt 60 stretched on the roller 63. The secondary transfer roller 64 is configured to allow a recording medium to pass through between the secondary transfer roller 64 and the intermediate transfer belt 60. Examples of the recording medium include sheets and plastic sheets.
The toner images on the photosensitive drums 1a, 1b, 1c, and 1d are sequentially primarily transferred to the intermediate transfer belt 60 by primary transfer rollers 6a, 6b, 6c, and 6d as primary transfer members at primary transfer portions T1a, T1b, T1c, and T1d as transfer portions. As a result, the toner images in four colors, yellow, magenta, cyan, and black, are superimposed on the intermediate transfer belt 60, forming a full-color image. The toner remaining on the photosensitive drum 1a that is not transferred to the intermediate transfer belt 60 is collected to the cleaning device 8a.
The full-color image on the intermediate transfer belt 60 is secondarily transferred to a recording medium fed from a feeding unit (not illustrated) by action of the secondary transfer roller 64 at a secondary transfer portion T2 the secondary transfer roller 64 and the intermediate transfer belt 60 form. The toner remaining on the surface of the intermediate transfer belt 60 that is not transferred to the recording medium is collected to an intermediate transfer belt cleaning device 65. The recording medium to which the toner image is transferred is conveyed to a fixing unit 7, is subjected to image fixation, and is then discharged to the outside of the apparatus.
In the present exemplary embodiment, the developer stored in the developing device 4a is a two-component developer in which negatively-charged non-magnetic toner and magnetic carrier are mixed. A non-magnetic toner (hereinafter, toner) contains a colorant, a wax component, and other materials in a resin, such as polyester and styrene, and is obtained by pulverizing or polymerizing the resultant product into powder. A magnetic carrier (hereinafter, carrier) is obtained by coating, with a resin, the surface layer of a core that consists of resin particles kneaded with magnetic powder, such as ferrite particles.
A toner developing process on the photosensitive drum 1a by the developing device 4a will be described. The developing device 4a includes a developing sleeve 41 as a developer carrier. The developing sleeve 41 develops an electrostatic latent image on the photosensitive drum 1a with the toner at a developing portion D facing the photosensitive drum 1a, into the toner image. More specifically, the photosensitive drum 1a is uniformly charged to a charging potential by a direct-current voltage or the voltage obtained by superimposing an alternating-current voltage on a direct-current voltage applied to the charger 2a. The image portions are exposed to laser beams from the laser beam scanner 3a, making the potential at the exposed positions an exposure potential or exposure potentials, forming the electrostatic latent image on the photosensitive drum 1a. In the present exemplary embodiment, the voltage applied to the charger 2a is a voltage obtained by superimposing an alternating-current voltage of a sine wave having a peak-to-peak voltage of 1200 [V] and a frequency of 2 [kHz] on a direct-current voltage of −500 [V]. The application of the voltage makes the charging potential −500 [V], and the exposure potential −150 [V].
The developing device 4a conveys the developer to the developing portion D using the developing sleeve 41. A direct-current voltage or the voltage obtained by superimposing an alternating-current voltage on a direct-current voltage is applied to the developing sleeve 41. In the present exemplary embodiment, the voltage obtained by superimposing an alternating-current voltage of a rectangular wave having a duty ratio of 60%, a peak-to-peak voltage of 1400 [V], and a frequency of 12 [KHz] on a direct-current voltage of −350 [V] is applied to the developing sleeve 41. Through the electric field formed between the charged potential and the exposure potential of the photosensitive drum 1a and the developing sleeve 41, the negative toner in the developer is conveyed to the electrostatic latent image on the photosensitive drum 1a at the exposure potential to be developed.
Carrier collection devices 5a, 5b, 5c, and 5d will be described with reference to
The magnet roller 51 includes a plurality of (three in the present exemplary embodiment) magnetic poles (magnet pieces) 51a, 51b, and 51c. The magnetic pole 51a is disposed at a position facing the photosensitive drum 1a with the collection roller 52 in between. The magnetic pole 51a is a magnetic pole for attracting the carrier adhering to the outer peripheral surface of the photosensitive drum 1a, and is therefore disposed at a position P1 where the photosensitive drum 1a and the collection roller 52 are closest to each other. The magnetic pole 51b is disposed downstream of the magnetic pole 51a in the rotation direction of the collection roller 52, and has the polarity different from that of the magnetic pole 51a. The magnetic pole 51c is disposed adjacent to and downstream of the magnetic pole 51b in the rotation direction of the collection roller 52, and has the same polarity as that of the magnetic pole 51b.
The collection roller 52 rotates in the arrow direction in
In place of or in addition to the configuration of the repulsive magnetic field formed with the magnetic poles 51b and 51c, a blade can be disposed facing the collection roller 52 to peel off the carrier from the collection roller 52. For example, the blade can be disposed facing the collection roller 52, with a gap, downstream of the position where the collection roller 52 faces the photosensitive drum 1a in the rotation direction of the collection roller 52.
The conveyance screw 54 as a carrier conveyance member includes a rotary shaft made of a nonmagnetic metal, and a blade made of a resin in a spiral shape around the rotary shaft. The conveyance screw 54 rotates to convey the fallen carrier from the collection roller 52 in the rotation axis direction. In the present exemplary embodiment, the rotation axis direction of the conveyance screw 54 and the rotation axis direction of the collection roller 52 are substantially parallel to each other.
The voltage obtained by superimposing an alternating-current voltage on a direct-current voltage is applied to the collection roller 52 from a collection high-voltage substrate 130 (see
Toner adhesion to the collection rollers 52 will now be described. As described above, the voltages are applied to the collection rollers 52 in order to facilitate collection of the carrier on the surfaces of the photosensitive drums 1a to 1d at the positions P1 where the photosensitive drums 1a to 1d and the respective collection rollers 52 are closest to each other. At this time, so-called fog toner on the surfaces of the photosensitive drums 1a to 1d is also collected by the respective collection rollers 52. In other words, the toner adheres to the collection rollers 52.
The toner inside the developing devices 4a to 4d is negatively-charged, whereas most of the toner adhering to the collection rollers 52 is weakly-charged toner mainly having no charge (i.e., toner having a charge amount of zero or close to zero), or reversely-charged toner (i.e., positively-charged toner). Such toner adheres to the background of an image as fog toner. The toner in the normally charged state adheres to the photosensitive drums 1a to 1d by electrostatic force, but the adhesion of the weakly-charged toner and the reversely-charged toner to the photosensitive drums 1a to 1d by electrostatic force is weak. The positions P1 where the collection rollers 52 and the respective photosensitive drums 1a to 1d are closest to each other facilitates transfer of weakly-charged toner and reversely-charged toner to the collection rollers 52.
Since the toner is a non-magnetic material, the toner transferred to the collection rollers 52 is not affected by the magnetic force generated from the magnetic poles of the magnet rollers 51, and is moved while being fixed to the surfaces of the collection rollers 52. When the toner reaches the magnetic poles 51b and 51c as peeling pole portions, the toner is rubbed by the carrier staying at the peeling pole portions, is accumulated together with the carrier, and is eventually collected into the collection chambers 53.
Insufficient amounts of carrier on the collection rollers 52 lead to insufficient amounts of carrier staying at the peeling pole portions, which results in insufficient collections of the toner at the peeling pole portions. In this case, the toner is accumulated on the collection rollers 52. When gaps between the photosensitive drums 1a to 1d and the respective collection rollers 52 are filled with the toner on the collection rollers 52, toner on the collection rollers 52 again adheres to the photosensitive drums 1a to 1d (so-called toner dripping occurs). As a result, toner is transferred to an output product as an image noise. In the present exemplary embodiment, the toner adhering to the collection rollers 52 is collected by the conductor members 56 described immediately below.
The conductor members 56 will now be described. While the following is a description of the carrier collection device 5a, the carrier collection devices 5b to 5d have the same configuration as each other. As illustrated in
As illustrated in
The surface of the upper lid 55c facing the collection roller 52 has a curved shape along the surface of the collection roller 52. The conductor member 56 is fixed in a curved state along the curved surface of the upper lid 55c. The conductor member 56 has a function as a toner collection section mainly collecting low-charged toner collected together with the carrier on the photosensitive drum 1a by the collection roller 52.
The conductor member 56 is a sheet-like member including a metal layer provided on the surface of its resin layer. In the present exemplary embodiment, the conductor member 56 is a member having a layer configuration in which an aluminum foil is vapor-deposited on a polyester film, and has a sheet shape with a width (the length in a direction orthogonal to the longitudinal direction) of 4 mm. As the conductor member 56, for example, ALPET® is available from PANAC Co., Ltd.
The conductor member 56 extends in substantially parallel with the longitudinal direction of the collection roller 52.
In the present exemplary embodiment, as illustrated in
As described above, the direct-current voltage is applied to the conductor member 56. The direct-current voltage applied to the conductor member 56 is the direct-current component alone as the voltage applied from the collection high-voltage substrate 130 common to the collection roller 52. In the present exemplary embodiment, a direct-current voltage of −600 [V] is applied to the conductor member 56.
As described above, the direct-current component voltage is applied to the conductor member 56 and the collection roller 52 from the collection high-voltage substrate 130. Thus, when an image forming operation is started, the conductor member 56 and the collection roller 52 have the same direct-current potential at the same timing. Thus, an alternating-current electric field is formed between the conductor member 56 and the collection roller 52 by the alternating-current voltage applied to the collection roller 52. The electric field causes low-charged toner on the collection roller 52 to be collected to the conductor member 56. In other words, in the present exemplary embodiment, toner is removed from the collection roller 52 by the conductor member 56 in parallel with the operation of collecting the carrier by the collection roller 52 during an image forming operation.
At the timing when the photosensitive drum 1a charged by the charger 2a reaches the position facing the developing sleeve 41, the direct-current voltage of the developing sleeve 41 rises. Further, at the timing when the photosensitive drum 1a reaches the position facing the collection roller 52, the direct-current voltage of the collection roller 52 rises. This is designed to prevent toner and carrier on the developing sleeve 41 or the collection roller 52 from unintentionally adhering to the photosensitive drum 1a due to a mismatch of the timings of voltage applications to the developing sleeve 41 and the collection roller 52 for the region of the photosensitive drum 1a charged to the charged potential.
When the voltage applications are ended (turned off), the alternating-current voltages of the developing sleeve 41 and the collection roller 52 are first turned off. The direct-current voltages of the charger 2a, the developing sleeve 41, and the collection roller 52 are then turned off in this order. At the timing when the charging of the photosensitive drum 1a by the charger 2a ends, the photosensitive drum 1a is discharged, and the region reduced to 0 [V] reaches the position facing the developing sleeve 41, the direct-current voltage of the developing sleeve 41 is turned off. Further, at a timing when the region reduced to 0 [V] reaches the position facing the collection roller 52, the direct-current voltage of the collection roller 52 is turned off. This is designed to prevent toner and carrier on the developing sleeve 41 or the collection roller 52 from unintentionally adhering to the photosensitive drum 1a due to a mismatch of the timings of ending voltage applications of the developing sleeve 41 and the collection roller 52 for the charged region of the photosensitive drum 1a, as with the application start timings. Finally, the alternating-current voltage of the charger 2a is turned off. In the present exemplary embodiment, the application start/end timings of the conductor member 56 are synchronized with those of the collection roller 52 since the direct-current component voltage by the collection high-voltage substrate 130 common to the collection roller 52 is applied to the conductor member 56.
As described above, in the present exemplary embodiment, the conductor member 56 is provided in the carrier collection device 5a, and the electric field is formed between the collection roller 52 and the conductor member 56, which makes it possible to remove toner accumulated on the collection roller 52 during an image forming operation. Thus, the configuration according to the present exemplary embodiment enables removal of toner from the collection roller 52 without increasing the downtime.
If the distance between the conductor member 56 and the collection roller 52 is excessively small, a leakage phenomenon can occur, whereas if the distance is excessively large, the effect by the electric field is weakened, reducing the effect on the toner collection. As a result, the distance between the conductor member 56 and the collection roller 52 desirably falls within the range of 0.2 [mm] to 3.0 [mm] at the closest position. In the present exemplary embodiment, the distance is 0.5 [mm].
In the longitudinal direction of the collection roller 52, the phenomenon that the toner adheres to the collection roller 52 remarkably occurs in the region where the magnet roller 51 is present. The conductor member 56 is, thus, desirably longer than the magnet roller 51 in the longitudinal direction as illustrated in
When the image forming operation is repeated, the collected toner is accumulated on the conductor member 56. When the accumulated toner falls on the photosensitive drum 1a, or adheres to the photosensitive drum 1a again via the collection roller 52, an image stain can occur. The conductor member 56 is, thus, desirably disposed above the collection roller 52 in the vertical directions. Even when the toner is continuously accumulated on the conductor member 56, the arrangement prevents an image stain caused by toner being rubbed with the collection roller 52 and adhered to the photosensitive drum 1a from occurring.
The conductor member 56 is desirably disposed downstream of the position (closest position P1) where the collection roller 52 faces the photosensitive drum 1a in the rotation direction of the collection roller 52 and upstream of the position where the collection roller 52 faces the collection chamber 53. Even when toner accumulated on the conductor member 56 falls on the collection roller 52, the arrangement enables collection of the toner to the collection chamber 53 before the toner is conveyed to the position facing the photosensitive drum 1a.
In the developing device 4a, the toner charged by friction with the carrier basically has the negative polarity. The toner adhering to the collection roller 52, however, mainly includes toner with an extremely low negative charge or toner with a reverse polarity charge. In the present exemplary embodiment, the polarity of the direct-current voltage applied to the collection roller 52 is negative, and has a potential difference from the charged potential as described above. Further, the voltage applied to the conductor member 56 as the direct-current component of the voltage applied to the collection roller 52 makes the conductor member 56 and the collection roller 52 have the same potential, whereby the alternating-current electric field collects toner on the collection roller 52. In other words, in the present exemplary embodiment, the direct-current voltage applied to the conductor member 56 is equal in magnitude to the direct-current voltage applied to the collection roller 52. Even when the potential relationship between the collection roller 52 and the conductor member 56 is changed to other relationships, similar effects are achievable. Modifications will now be described in which the configuration of the voltage application to the collection roller 52 and the conductor member 56 is changed.
A first modification will be described. In the first modification, the voltage is applied to the conductor member 56 with a configuration illustrated in
As illustrated in
A second modification will be described. In the second modification, the voltage is applied to the conductor member 56 with a configuration illustrated in
As illustrated in
A third modification will be described. In the third modification, the voltage applied to the conductor member 56 is a direct-current voltage applied from a toner collection high-voltage substrate 140, different from the collection high-voltage substrate 130 applying the voltage to the collection roller 52, as illustrated in
When an image forming operation is started, the toner collection high-voltage substrate 140 generates the direct-current voltage at the same timing as that of the collection high-voltage substrate 130, and applies the voltage to the conductor member 56. In the third modification, a direct-current voltage of −600 [V] is applied to the collection roller 52, and a direct-current voltage of −300 [V] is applied to the conductor member 56. Thus, the potential difference of the conductor member 56 from the collection roller 52 is +300 [V]. In other words, in the third modification, the direct-current voltage applied to the conductor member 56 is a voltage of a magnitude at which the difference from the direct-current voltage applied to the collection roller 52 has the positive polarity, as in the first modification.
A fourth modification will be described. The fourth modification has a configuration in which the conductor member 56 is connected to a ground potential, illustrated in
A fifth modification will be described. In the fifth modification, as illustrated in
Between the configuration according to the example as the above-described first exemplary embodiment and the configurations according to the above-described first to fifth modifications, the potential of each conductor member 56 was set with a similar amount of toner adhering to the collection rollers 52 (a toner weight per unit area was about 1.2 [mg/cm2]), and the degree of toner remaining on each collection roller 52 after twenty rotations of the collection roller 52 was compared.
Table 1 illustrates the voltage applied to the conductor member 56, the potential difference between the conductor member 56 and the collection roller 52, the toner remaining percentage on the collection roller 52, and the complexity in each of the configurations. The toner remaining percentage on the collection roller 52 was calculated from a measurement value of toner weight on the collection roller 52 before and after the twenty rotations of the collection roller 52. As for “complexity and cost of configuration”, the configuration that is not complicated and prevents an increase in cost was evaluated as “good”. The configuration that is less complicated and prevents a more increase in cost compared with “good” was evaluated as “excellent”, the configuration that is slightly more complicated and prevents an less increase in cost compared with “good” was evaluated as “slightly insufficient”, and the configuration that is more complicated and prevents a slight increase in cost compared with “slightly insufficient” was evaluated as “insufficient”.
In terms of “toner remaining percentage on collection roller 52” in Table 1, a good result is observed in the configuration according to the example in which the potential difference between the conductor member 56 and the collection roller 52 is equal or in the configuration according to each of the first, third, and fourth modifications in which the potential of the conductor member 56 is greater in the positive direction than that of the potential of the collection roller 52. This results from the adhered toner on the collection roller 52 having a low charge with a large percentage of the negatively charged toner.
In contrast, in the configuration according to the second modification in which the potential of the conductor member 56 is greater in the negative direction than that of the collection roller 52, the toner collection ratio is slightly lower than those in the configurations according to the example and the first, third, and fourth modifications. This results from the configuration according to the second modification facilitating collection of positively-charged toner and the slightly small percentage of positively-charged toner out of the toner adhering to the collection roller 52.
In the fifth modification, no connection to a high-voltage substrate or contact with the ground potential is necessary, resulting in a very simple configuration, which however provides a less effect of the toner collection than those in the configurations of the example and the other modifications.
The third modification includes the toner collection high-voltage substrate 140 added, which could cause increased cost and size of the apparatus. However, the toner collection high-voltage substrate 140 is independent of the collection high-voltage substrate 130, which makes it possible to determine the voltage irrespective of the voltage applied to the collection roller 52. This has advantages in facilitating change of the potential difference between the collection roller 52 and the conductor member 56 to an optimum value, and of the timings when the voltages are applied to the collection roller 52 and the conductor member 56, based on the environment where the image forming apparatus is used.
As described above, any configuration provides a certain effect while the degree varies depending on the potential relationship. While the conductor member 56 is not an insulator, such as a resin, but a conductor to have a uniform potential in its longitudinal direction, the potential relationship between the conductor member 56 and the collection roller 52 can be other than the above-described examples. When the potential difference from the collection roller 52 falls within a range of −1000 [V] to +1000 [V], leakage does not occur, providing a certain effect of collecting toner from the collection roller 52 during an image forming operation.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2023-130215, filed Aug. 9, 2023, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-130215 | Aug 2023 | JP | national |
