This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2022-091526, filed on Jun. 6, 2022, and No. 2023-060073, filed on Apr. 3, 2023, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
Embodiments of the present disclosure relate to a transfer device and an image forming apparatus.
An image forming apparatus that prints a color image typically includes a transfer device for transferring toner of a special color such as a transparent color or a white color in addition to four colors of yellow (Y), magenta (M), cyan (C), and black (K). In such an image forming apparatus, first, toner images of the four colors are transferred to an intermediate transferor at primary transfer sections. Then, a multi-color toner image is secondarily transferred to a recording sheet such as a sheet of paper by a secondary transfer section.
For example, in addition to the four colors of YMCK, a primary transfer section that transfers a toner image of a transparent color is disposed most downstream on an intermediate transfer belt in a rotation direction of the intermediate transfer belt. When the toner image of the transparent color is not formed, a primary transfer roller of the primary transfer section corresponding to the transparent color is separated from a photoconductor, and a toner image forming device of the transparent toner is stopped.
In an embodiment of the present disclosure, a transfer device includes an intermediate transferor to rotate and multiple primary transfer sections. The multiple primary transfer sections each includes a primary transferor to contact the intermediate transferor and a primary transfer nip between the primary transferor and a latent image bearer with the intermediate transferor interposed between the primary transferor and the latent image bearer. The multiple primary transfer sections includes a most-upstream primary transfer section most upstream among the multiple primary transfer sections in a rotation direction of the intermediate transferor and a most-downstream primary transfer section most downstream among the multiple primary transfer sections in the rotation direction. One of the most-upstream primary transfer section and the most-downstream primary transfer section is a special-color primary transfer section to transfer developer of a special color other than any of yellow, magenta, cyan, and black colors. The special-color primary transfer section is switchable between the most-upstream primary transfer section and the most-downstream primary transfer section. The primary transferor of each of the most-upstream primary transfer section and the most-downstream primary transfer section is switchable between a contact position at which the primary transferor contacts the latent image bearer with the intermediate transferor interposed between the primary transferor and the latent image bearer and a separation position at which the primary transferor is separated from the latent image bearer. With only the primary transferor of the special-color primary transfer section arranged at the separation position, the primary transferor of any other primary transfer section than the special-color primary transfer section is arranged at the contact position to transfer an image.
In another embodiment of the present disclosure, an image forming apparatus includes the transfer device and latent image bearers including the latent image bearer.
A more complete appreciation of the disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein:
The accompanying drawings are intended to depict embodiments of the present invention and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.
In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.
Referring now to the drawings, embodiments of the present disclosure are described below As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Embodiments of the present disclosure are described below with reference to the drawings in the following description. Note that like reference numerals are assigned to like or equivalent components and a description of those components may be simplified or omitted.
As illustrated in
In the image former 1A, image forming devices 10K, 10C, 10M, 10Y, and 10T are arranged. The image forming devices 10K, 10C, 10M, and 10Y can form images with toners of colors of yellow, magenta, cyan, and black, respectively, in a complementary color relation. The image forming device 10T forms a glossy image with transparent toner. In each of the image forming devices 10K, 10C, 10M, 10Y, and 10T, photoconductors 3K, 3C, 3M, 3Y, and 3T, respectively, that can bear images are arranged in parallel along the stretched surface of the intermediate transfer belt 2. The photoconductor 3T bears an image of a transparent toner. In the following description, each of the photoconductors 3K, 3C, 3M, 3Y, and 3T may be simply referred to as a photoconductor 3 in a case in which a similar description applies to all the photoconductors 3K, 3C, 3M, 3Y, and 3T.
Each of the photoconductors 3K, 3C, 3M, 3Y, and 3T is made of a drum rotatable in the same direction, which is a counterclockwise direction in
A transfer device 20 includes the intermediate transfer belt 2, primary transfer rollers 7K, 7Y, 7M, 7C, and 7T (see
Toner images formed in the image forming devices 10K, 10C, 10M, 10Y, and 10T including the photoconductors 3K, 3C, 3M, 3Y, and 3T, respectively, are sequentially transferred to the intermediate transfer belt 2. The intermediate transfer belt 2 is stretched around the rollers 2A and 2B, the secondary-transfer backup roller 2C, and multiple rollers that are not denoted with reference numerals in
A recording sheet is fed to the secondary transfer nip from a sheet feeder 1B. The sheet feeder 1B includes multiple sheet feed trays 1B1 and multiple conveyance rollers 1B2. The multiple conveyance rollers 1B2 are disposed on a conveyance path of recording sheets fed from the sheet feed trays 1B1.
The photoconductors 3K, 3C, 3M, 3Y, and 3T are irradiated with writing light by the corresponding one of the writing devices 5, and electrostatic latent images corresponding to image data are formed on the photoconductors 3K, 3C, 3M, 3Y, and 3T. The image data is obtained by scanning a document on the document loading table 1C1 disposed in the document scanner 1C, or by image data output from a computer.
The document scanner 1C includes a scanner 1C2 and an automatic document feeder 1C3. The scanner 1C2 exposes and scans a document on the document loading table 1C1. The automatic document feeder 1C3 is disposed above an upper surface of the document loading table 1C1. The automatic document feeder 1C3 inverts a document fed onto the document loading table 1C1 to scan front and back sides of the document.
Each of the electrostatic latent images on the photoconductors 3K, 3C, 3M, 3Y, and 3T formed by the writing devices 5 is subjected to visual image processing by the corresponding one of the developing devices 6K, 6C, 6M, 6Y and 6T and primarily transferred to the intermediate transfer belt 2. The developing device 6T is illustrated in
Subsequently, a multicolor image to be fixed borne on the surface of the recording sheet on which the secondary transfer has been performed is fixed by the fixing device 11. The fixing device 11 has a belt fixing structure in which a fixing belt heated by a heating roller and a pressure roller facing and in contact with the fixing belt are disposed. In such a configuration, a contact area, in other words, a nip area is disposed between the fixing belt and the pressure roller, thus allowing an area in which the recording sheet is heated to be increased as compared with a heat-roller fixing structure.
A conveyance direction of the recording sheet that has passed through the fixing device 11 can be switched by a conveyance-path switching claw disposed in a rear portion of the fixing device 11. Specifically, the conveyance direction of the recording sheet is selected between the conveyance path directed to a sheet ejector 13 and a reverse conveyance path RP the conveyance-path switching claw.
In the image forming apparatus 1 having the above-described configuration, electrostatic latent images are formed on the uniformly charged photoconductors 3K, 3C, 3M, 3Y, and 3T by exposure scanning of a document placed on the document loading table 1C1 or by reading image data from a computer. Subsequently, the electrostatic latent images are subjected to visual image processing by the developing devices 6K, 6C, 6M, 6Y, and 6T. Then, the toner images are primarily transferred to the intermediate transfer belt 2.
In the case of a single-color image, a toner image that has been transferred to the intermediate transfer belt 2 is transferred onto a recording sheet fed from the sheet feeder 1B as is. In the case of a multi-color image, primary transfer is repeated such that toner images are superimposed one on another. Then, the toner images are secondarily transferred to the recording sheet collectively. The unfixed image that has been secondarily transferred onto the recording sheet is fixed by the fixing device 11. Then, the recording sheet is fed to the sheet ejector 13 or reversed and fed again to the secondary transfer nip.
In
The intermediate transfer belt 2 is stretched around at least the roller 2A and the roller 2B as a roller pair and the secondary-transfer backup roller 2C disposed at the secondary transfer nip. The roller 2A as a driving roller is set to rotate clockwise such that the intermediate transfer belt 2 moves in the direction indicated by arrow A illustrated inside the intermediate transfer belt 2 in
The primary transfer rollers 7K, 7Y, 7M, 7C, and 7T according to the present embodiment are cored bars made of metal such as iron, steel use stainless (SUS), or aluminum (Al) coated with foam resin. The foam resin has a wall thickness of 2 mm to 10 mm. Note that known blade-shaped or brush-shaped transferors can also be employed as the transferors.
In the present embodiment, white toner is employed for the purpose of forming a white base color for an image in addition to toner employed for full-color image formation. In addition, transparent toner may be employed for the purpose of improving glossiness and transferability of an image, and, for example, light cyan toner, or light magenta toner may be selected for increasing a color gamut. For the purpose of creating a colored metal color such as a red copper color and a bronze color, toner of a metal color such as gold toner and silver toner may also be employed as a base.
As illustrated in
The transfer device 20 includes a most-upstream primary transfer section 201 disposed most upstream in the rotation direction of the intermediate transfer belt 2, a most-downstream primary transfer section 203 disposed most downstream in the rotation direction of the intermediate transfer belt 2, and a central primary transfer section 202 including the primary transfer rollers 7Y, 7M, and 7C disposed between the most-upstream primary transfer section 201 and the most-downstream primary transfer section 203. In the present embodiment, the most-upstream primary transfer section 201 transfers a black toner image at a black transfer nip NK, the central primary transfer section 202 transfers a cyan toner image at a cyan transfer nip NC, a magenta toner image at a magenta transfer nip NM, and a yellow toner image at a yellow transfer nip NY to the intermediate transfer belt 2. The most-downstream primary transfer section 203 transfers a special color toner image at a special color transfer nip NT to the intermediate transfer belt 2. Furthermore, in the following description, upstream or downstream in the rotation direction of the intermediate transfer belt 2 may be also referred to simply as upstream or downstream. The above-described special color is a color other than yellow; magenta, cyan, and black, and is, for example, clear color, white, gold, or silver.
In
In the present embodiment, a toner image of the special color can be transferred to the intermediate transfer belt 2 in both the most-upstream primary transfer section 201 and the most-downstream primary transfer section 203. Accordingly, a toner image of the special color can be transferred in a desired order. Details are described below.
Between the primary transfer roller 7C and the primary transfer roller 7T in the rotation direction of the intermediate transfer belt 2, a driven roller 21A as a second tension roller and a sensor 22 as a sensor are disposed. The driven roller 21A stretches the intermediate transfer belt 2. The sensor 22 detects a scale on the intermediate transfer belt 2 and detects the rotation speed of the intermediate transfer belt 2. Controlling the rotation speed of the intermediate transfer belt 2 based on the detection result of the sensor 22 prevents positional shift of toner images of the colors to be transferred to the intermediate transfer belt 2.
In the transfer device 20 according to the present embodiment, the primary transfer rollers 7K, 7Y, 7M, 7C, and 7T contact with and separate from the photoconductors 3K, 3Y, 3M, 3C, and 3T, respectively, with the intermediate transfer belt 2 interposed between the primary transfer rollers 7K, 7Y 7M, 7C, and 7T and the photoconductors 3K, 3Y, 3M, 3C, and 3T, respectively, in accordance with modes of image formation. Specifically, as described in modes A, B, C, D, E, and F in Table 1 below, the position of each of the primary transfer rollers 7K, 7Y, 7M, 7C, and 7T can be changed between a contact position and a separation position. The contact position is a position at which each of the primary transfer rollers 7K, 7Y, 7M, 7C, and 7T contacts the corresponding one of the photoconductors 3K, 3Y, 3M, 3C, and 3T, via the intermediate transfer belt 2 to form a primary transfer nip. The separation position is a position at which each of the primary transfer rollers 7K, 7Y, 7M, 7C, and 7T is separated from the corresponding one of the photoconductors 3K, 3Y, 3M, 3C, and 3T. In addition, the driven roller 21A around which the intermediate transfer belt 2 is stretched and the driven roller 33A that serves as a first tension roller also move in a direction away from the photoconductor 3T in conjunction with the primary transfer roller 7T of the most-downstream primary transfer section 203, in other words, in a downward direction in
Switching between the modes A, B, C, D, F, and F as described above allows only the primary transfer sections to form the primary transfer nips needed for image formation. Accordingly, the primary transfer nips are not formed by the primary transfer sections that are not needed for image formation. Thus, excessive toner consumption can be prevented. For example, in the case in which a monochrome image is formed on a recording sheet, in the mode F, the black transfer nip NK is formed only in the most-upstream primary transfer section 201. In particular, in the transfer device 20 according to the present embodiment in which the special color toner is transferred in the most-upstream primary transfer section 201 and the most-downstream primary transfer section 203, the primary transfer roller 7K of the most-upstream primary transfer section 201 and the primary transfer roller 7T of the most-downstream primary transfer section 203 are contactable to and separable from the photoconductors 3K and 3T, respectively. By so doing, the primary transfer roller 7K of the most-upstream primary transfer section 201 or the primary transfer roller 7T of the most-downstream primary transfer section 203 can be separated from the photoconductor 3K or 3T, respectively, as needed even when the special color toner is transferred either in the most-upstream primary transfer section 201 or the most-downstream primary transfer section 203. Accordingly, excessive consumption of the special color toner can be prevented in any of the modes A, B, C, D, E, and F.
When the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are arranged at the contact positions and the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the separation position, as indicated in the mode E, the primary transfer roller 7T is arranged at the large separation position. Thus, the driven roller 33A around which the intermediate transfer belt 2 is stretched is largely moved in the direction away from the photoconductor 3T. As a result, the position at which the intermediate transfer belt 2 is stretched can be changed to a position away from the photoconductor 3T. Such a configuration can prevent interference between the photoconductor 3T and the intermediate transfer belt 2 and damage to the photoconductor 3T and the intermediate transfer belt 2 due to the interference.
In some switching operations among the switching operations between the modes A, B, C, D, E, and F, the order of components that contact with or separate from the intermediate transfer belt 2 is preset. Specifically, in the case in which the mode A is switched to the mode E, the primary transfer roller 7T and the driven rollers 21A and 33A are moved first to the large separation positions. Then, the primary transfer rollers 7T, 7M, and 7C of the central primary transfer section 202 are moved to the contact positions.
By contrast, in the case in which the mode E is switched to the mode A, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are moved first to the separation positions. Then, the primary transfer roller 7T and the driven rollers 21A and 33A are moved to the small separation positions.
In the above-described cases, the position of the primary transfer roller 7K of the most-upstream primary transfer section 201 is switched between the separation position and the contact position at any suitable time. In the case in which the mode B is switched to the mode F, the primary transfer roller 7T and the driven rollers 21A and 33A are moved first to the small separation position. Then, the primary transfer roller 7K of the most-upstream primary transfer section 201 is moved to the contact position.
By contrast, in the case in which the mode F is switched to the mode B, the primary transfer roller 7K of the most-upstream primary transfer section 201 is moved first to the separation position. Then, the primary transfer roller 7T and the driven rollers 21A and 33A are moved to the contact position. In the case in which the mode E is switched to the mode F, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are moved first to the separation position. Then, the primary transfer roller 7T and the driven rollers 21A and 33A are moved to the small separation position.
By contrast, in the case in which the mode F is switched to the mode E, the primary transfer roller 7T and the driven rollers 21A and 33A are moved first to the large separation position. Then, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are moved to the contact position. As described above, the primary transfer roller 7T and the driven rollers 21A and 33A that are moved to the separation position are moved first. Accordingly, damage to the intermediate transfer belt 2 and the photoconductors 3K, 3C, 3M, 3Y, and 3T due to the contact of the intermediate transfer belt 2 and the photoconductors 3K, 3C, 3M, 3Y, and 3T can be prevented.
In the present embodiment, as described below, the primary transfer roller 7T and the driven rollers 21A and 33A are simultaneously moved by a common moving mechanism. In some embodiments, when the primary transfer roller 7T and the driven rollers 21A and 33A are moved by a different moving mechanism, the order in which the primary transfer roller 7T and the driven rollers 21A and 33A are moved may be any desired order.
Next, a first contact-and-separation mechanism as a first movement mechanism that causes the primary transfer roller 7T disposed in the most-downstream primary transfer section 203 to contact with and separate from the intermediate transfer belt 2 is described below First, a motor that is a driving source of the first contact-and-separation mechanism and components surrounding the motor are described with reference to
As illustrated in
The driving force of the motor 23 rotates a cam, to be described below, to cause the primary transfer roller 7T (see
A photosensor 28 (see
The motor 23 is driven by a predetermined number of pulses to rotate the feeler 27a counterclockwise to cause the primary transfer roller 7T to move from the large separation position at which the feeler 27a faces the photosensor 28 in
Next, the motor 23 is driven from the position in
The positions of the primary transfer roller 7T, the driven rollers 21A and 33A, and the sensor 22 are switched between the small separation position, the contact position, and the large separation position by the driving force of the single motor 23.
Further, the first contact-and-separation mechanism includes a motor that switches the primary transfer rollers 7Y 7M, and 7C of the central primary transfer section 202 between the contact position and the separation position, a feeler that detects the positions of the primary transfer rollers 7Y, 7M, and 7C, a motor that switches the primary transfer roller 7K of the most-upstream primary transfer section 201 between the contact position and the separation position, and a feeler that detects the position of the primary transfer roller 7K.
Next, an operation procedure of the most-upstream primary transfer section 201, the central primary transfer section 202, and the most-downstream primary transfer section 203 in different print modes below is described in order with reference to
The FC printing is described with reference to
As illustrated in
Then, the primary transfer rollers 7K, 7Y, 7M, 7C, and 7T are arranged at predetermined positions. To be more specific, the motor 23 (see
After driving of the motor 23 and the above-described motors are started, the controller 300 determines whether the feeler 27a is detected at a predetermined timing, in other words, whether the primary transfer rollers 7K, 7Y, 7M, 7C and 7T are arranged at the above-described respective predetermined positions (step S4). When the detection of the feeler 27a is normally performed, the controller 300 stops the motor 23 and the above-described motors and executes the printing operation (steps S5, S6, and s7). On the other hand, when the feeler 27a is not detected at the predetermined timing, some trouble may occur, for example, in the operation of the motors. For this reason, the motor 23 and the above-described motors and all the driving motors in the image forming apparatus 1 are stopped, and an error message is displayed on a display unit of the image forming apparatus 1, and the printing operation is ended (steps S12 and S13).
When the printing operation is normally finished, the controller 300 causes the primary transfer rollers 7K, 7Y, 7M, 7C and 7T to move to the respective separation positions. To be more specific, the controller 300 drives the motor 23 to move the primary transfer roller 7T and the driven rollers 21A and 33A to the separation positions and drives the motors such that the primary transfer rollers 7Y, 7M, 7C of the central primary transfer section 202 and the primary transfer roller 7K of the most-upstream primary transfer section 201 are moved to the separation position (step S8).
At this time also, the controller 300 determines whether the feelers have been detected at a predetermined timing (step S9). If the feelers have been detected at the predetermined timing, the controller 300 stops the motors at respective predetermined positions. Then, the controller 300 stops the driving motors in the image forming apparatus 1 to end the operation procedure (steps S10 and S11). When the feeler 27a has not been detected at the predetermined timing, the controller 300 stops all the motors, displays an error message on the display unit of the image forming apparatus and ends the printing operation (steps S12 and S13).
Further, in the case where the black (K) toner is not set in the most-upstream primary transfer section 201 in step S1, in other words, steps S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, and S25, which are performed when the black (K) toner is transferred by the primary transfer roller 7T of the most-downstream primary transfer section 203, also have a basic procedure similar to steps S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, and S13. As a difference from steps S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, and S13, in step S15, the controller 300 causes the primary transfer roller 7T of the most-downstream primary transfer section 203, which transfers the black (K) toner to move to the contact position and return to the separation position in step S20. The primary transfer roller 7K of the most-upstream primary transfer section 201 is not moved.
To be more specific, when the black (K) toner is set in the most-upstream primary transfer section 201, the primary transfer roller 7K of the most-upstream primary transfer section 201 is arranged at the contact position in step SA4, and then moved to the separation position in step SA8. When the black (K) toner is set in the most-downstream primary transfer section 203, the primary transfer roller 7T and driven rollers 21A and 33A are arranged at the contact positions in step SA15, and then moved to the separation positions in step SA20.
Next, a first contact-and-separation mechanism 91 that causes the primary transfer roller 7T, the driven roller 21A, and the driven roller 33A to operate by the driving force of the motor 23 is described with reference to
As illustrated in
The first cam 31E contacts a front slider 32 that serves as a slider. As illustrated in
A driven roller 33A, which is one of rollers around which the intermediate transfer belt 2 is stretched, is disposed at one end of the rotator 33. The rotator 33 is rotatable about a rotation fulcrum 33a.
The rotator 33 includes a hole 33b at an end of the rotator 33 opposite to another end of the rotator 33 on which the driven roller 33A is disposed. An insertion portion 32a disposed on the front slider 32 is inserted in the hole 33b. The insertion portion 32a is formed by press-fitting a ball bearing into a shaft fixed to the front slider 32. Providing the ball bearings in the insertion portion 32a can reduce sliding resistance between the insertion portion 32a and the rotator 33.
The primary transfer roller 7T is disposed at one end of a rotator 34. The rotator 34 is rotatable about a rotation fulcrum 34a. The rotator 34 includes a hole 34b at an end of the rotator 34 opposite to another end of the rotator 34 on which the primary transfer roller 7T is disposed. A pin 32b disposed on the front slider 32 is inserted in the hole 34b.
A spring 35 is fixed to a housing of the image forming apparatus 1 and biases the rotator 34 in a direction in which the rotator 34 rotates clockwise in
When the front slider 32 moves in the left-right direction in
Alternatively, when the front slider 32 moves in the left direction in
As illustrated in
The driven roller 21A is disposed at one end of the rotator 21. The rotator 21 is rotatable about a rotation fulcrum 21a. The rotator 21 receives a force from a spring 39 acting in a direction such that the rotator 21 rotates clockwise about the rotation fulcrum 21a.
In
Further, when the first cam 31A is rotated to a predetermined position to cause the primary transfer roller 7T of the most-downstream primary transfer section 203 to be arranged at the large separation position, the front slider 32 moves to the right relative to
For example, as illustrated in
When the primary transfer roller 7T is arranged at the small separation position in
The driven roller 33A stretches the intermediate transfer belt 2 in all the states of
Next, when the front slider 32 moves in the right direction in
As described above, changing the position of the driven roller 33A at timings when the primary transfer roller 7T is arranged at the contact position, the small separation position, and the large separation position allows the position at which the intermediate transfer belt 2 is stretched by the driven roller 33A in each state to be changed.
Accordingly, the intermediate transfer belt 2 can be stretched at a favorable position, and the rotation speed of the intermediate transfer belt 2 can be accurately detected by the sensor 22. In particular, in the present embodiment, the driven roller 33A is disposed downstream from the primary transfer roller 7T of the most-downstream primary transfer section 203. The position at which the intermediate transfer belt 2 is stretched by the driven roller 33A is changed in all of the three positions of the driven roller 33A described above. Thus, the posture of the intermediate transfer belt 2 in which the intermediate transfer belt 2 is stretched in each of the states can be appropriately changed. Accordingly, the sensor 22 can accurately detect the rotation speed of the intermediate transfer belt 2.
Furthermore, specifically in the above-described mode E in which the primary transfer roller 7T is arranged at the large separation position, the rotator 33 is largely rotated counterclockwise in
In the mode E, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 contact the intermediate transfer belt 2 to lift the intermediate transfer belt 2. Accordingly, the intermediate transfer belt 2 is located at a position closer to the photoconductor 31 Accordingly, shifting the position at which the intermediate transfer belt 2 is stretched downward in
Next, a mechanism for moving the sensor 22 among the mechanisms included in the first contact-and-separation mechanism 91 is described below.
As illustrated in
As illustrated in
In addition, when the front slider 32 moves, the first arm 37 with the rotation fulcrum 37a fixed to the front slider 32 moves in the left-right direction in
As illustrated in
As illustrated in
In the present embodiment, the contact portion 60a that functions as the slip-off stopper to prevent the first arm 37 from coming off the front slider 32 and the restricting portion 60b that regulates the direction in which the first arm 37 moves relative to the second. cam 31B are integrated with the thrust stopper 60. Accordingly, the number of components of the transfer device 20 can be reduced. However, the contact portion 60a and the restricting portion 60b may be disposed as separate components.
As illustrated in
The bearing 40 includes a parallel pin 40a that serves as a slip-off stopper in a rear portion of the bearing 40. The length of the parallel pin 40a is set to be shorter than the length of the elongated hole 38a in the longitudinal direction of the elongated hole 38a. Arranging the parallel pin 40a substantially parallel to the longitudinal direction of the elongated hole 38a allows the bearing 40 to be inserted into the elongated hole 38a. As described above, in the three states in which the primary transfer roller 7T is arranged at the contact position, the small separation position, and the large separation position, the parallel pin 40a does not rotate to a position at which the parallel pin 40a, is parallel to the longitudinal direction of the elongated hole 38a. Accordingly, the parallel pin 40a functions as the slip-off stopper to prevent the bearing 40 from coming off the elongated hole 38a.
As illustrated in
Rotation of the cant 31 causes the front slider 32 to be moved from the position of the front slider 32 in
Accordingly, the end 37b of the first arm 37 moves downward in
As illustrated in
A restrictor 63 is fixed to the first sensor bracket 43. A pin 32d of the front slider 32. is inserted into a hole 63a of the restrictor 63. When the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the contact position in
The second sensor bracket 44 is fixed to the first sensor bracket 43 via a stud 43b disposed on the first sensor bracket 43. The second sensor bracket 44 holds the sensor 22. The second sensor bracket 44 includes a hook 44a to which one end of a spring 62 (see
When the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the contact position in
On the other hand, in the state in which the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the small separation position in
A pin 43c disposed on the first sensor bracket 43 illustrated in
Accordingly, the first sensor bracket 43, the second sensor bracket 44, and the sensor 22 rotate counterclockwise in
When the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the large separation position in
Accordingly, the second sensor bracket 44 fixed to the first sensor bracket 43 via the stud 43b moves upward in
In other words, the upward movement of the second sensor bracket 44 and the sensor 22 in
As described above, the driving force of the cam 31 is transmitted to the first sensor bracket 43 via the link members such as the first arm 37 and the second arm 38 to rotate the first sensor bracket 43. By so doing, the first sensor bracket 43 can be rotated in a desired direction.
In particular, in the present embodiment, the rotational force of the first arm 37 is transmitted to the second arm 38 only when a predetermined condition is satisfied. Accordingly, the driving force by the rotation of the cam 31 to the sensor 22 can be transmitted only when a specific positional change is performed.
To be more specific, the second arm 38 is connected to the first arm 37 and the first sensor bracket 43 via the elongated holes 38a and 38b, respectively, disposed in the second arm 38. Accordingly, the second arm 38 can be retracted to move the sensor 22 downward, for example, in
In other words, compared with the primary transfer roller 7T and the driven rollers 21A and 33A that move in a constant direction with the movement of the front slider 32, the sensor 22 moves upward in
When the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the small separation position, the primary transfer roller 7K of the most-upstream primary transfer section 201 and the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 separate from the photoconductors 3K, 3Y, 3M, and 3C, respectively. Accordingly, the position at which the intermediate transfer belt 2 is stretched moves downward in
On the other hand, when the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the large separation position, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 contact the photoconductors 3Y, 3M, and 3C, respectively, via the intermediate transfer belt 2. Thus, the position at which the intermediate transfer belt 2 is stretched is pushed upward in
Accordingly, changing the position of the sensor 22 as described above allows the sensor 22 to be positioned at a favorable position corresponding to the position at which the intermediate transfer belt 2 is stretched. Accordingly, in each of the modes A, B, C, D, E, and F, the detection accuracy of the sensor 22 with respect to the intermediate transfer belt 2 can be enhanced, and the traveling speed or rotation speed of the intermediate transfer belt 2 can be controlled with high accuracy.
Further, the first contact-and-separation mechanism 91 can perform the operation of the sensor 22 and the operations of the primary transfer roller 7T and the driven rollers 21A and 33A by the driving force of the motor 23 as a single driving source. Accordingly, energy saving and a reduction in the number of components of the transfer device 20 can be achieved.
However, the number of link members coupled to the first sensor bracket 43 holding the sensor 22 is not limited to two as in the present embodiment. In some embodiments, the number of the link members may be three or greater than or one. Further, the combination of the elongated hole and the insertion member such as a pin inserted into the elongated hole may be reversed. It is not necessarily need to operate all of the sensor 22, the primary transfer roller 7T, and the driven rollers 21A and 33A by the driving force of the motor 23.
As described above, in the present embodiment, the rotation of the first cam 31A illustrated in
Furthermore, rotation of the first cam 31A and the second cam 31B can cause the sensor 22 to move. To be specific, when the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the contact position in
Next, a second contact-and-separation mechanism 92 as a second movement mechanism and a third contact-and-separation mechanism 93 as a third movement mechanism are described with reference to
As illustrated in
The rotators 46, 47, 48, and 49 are rotatable about the rotation fulcrums 46a, 47a, 48a, and 49a, respectively. The primary transfer roller 7C is disposed at one end of the rotator 46. The primary transfer roller 7M is disposed at one end of the rotator 47.
The primary transfer roller 7Y is disposed at one end of the rotator 48. The primary transfer roller 7K is disposed at one end of the rotator 49. The rotators 46, 47, 48, and 49 are biased by springs to be rotated clockwise in
The cam follower 52 rotates by the rotation of the cam 51, and a front slider 50 of the most-upstream primary transfer section 201 moves in the right direction in
Accordingly, the primary transfer rollers 7C, 7M, and 7Y move away from the intermediate transfer belt 2. Further, the rotation of the cam 53 causes the cam follower 54 to rotate and one end of the rotator 49 opposite to another end of the rotator 49 at which the primary transfer roller 7K is disposed is pressed.
Accordingly, the rotator 49 rotates counterclockwise in
Next, a toner supply device that supplies toner to corresponding one of the developing devices 6Y, 6M, 6C, 6K, and 6T is described with reference to
As illustrated in
Bottle drivers 103Y, 103M, 103C, 103K, and 103T (see
The toner supply device 150 includes a bottle driver 103, a pre-supply reservoir 104, to a toner supply unit 105, a suction pump 106, and a transfer tube 107. The pre-supply reservoir 104 is disposed directly above the developing device 6. The transfer tube 107 includes one end connected to the bottle driver 103 and the other end connected to the suction pump 106 to form a toner conveyance path to transfer toner from the bottle driver 103 to the pre-supply reservoir 104. In the present embodiment, the transfer tube 107 is a flexible tube. When the bottle driver 103 drives the toner bottle 102 to rotate, toner contained in the toner bottle 102 is transferred from a head opening of the toner bottle 102 to the bottle driver 103. Suction operation of the suction pump 106 causes toner in the bottle driver 103 to be transferred to the suction pump 106 via the transfer tube 107. At the same time, the toner sucked from the bottle driver 103 is dropped into the pre-supply reservoir 104 from a discharge port of the suction pump 106.
Rotation of the toner supply unit 105 causes the toner stored in the pre-supply reservoir 104 to be supplied to the developing device 6 via a toner supply path 108. As described above, in the present embodiment, the toner transferred from the bottle driver 103 to the vicinity of the developing device 6 by the suction pump 106 is temporarily stored in the pre-supply reservoir 104.
Note that, for example, in the case in which a white toner is employed as a special color to form a white background in an image, a white toner layer is formed at a lowermost layer of the image. For this reason, the most-downstream primary transfer section 203 is arranged most downstream among the most-upstream primary transfer section 201, the central primary transfer section 202, and the most-downstream primary transfer section 203. Alternatively, when a transparent toner image is transferred to apply glossiness to an image, the transparent toner image is formed on the surface of the image. For this reason, in this case, the most-downstream primary transfer section 203 is arranged most upstream among the most-upstream primary transfer section 201, the central primary transfer section 202, and the most-downstream primary transfer section 203.
As described above, in order to Change the order in which the toner of the special color is primarily transferred in accordance with the type of the special color to be employed, in the present embodiment, the toner supplied to the most-upstream primary transfer section 201 and the most-downstream primary transfer section 203 can be changed as illustrated in
Specifically, in
In addition, in
In contrast to the transfer tube 107T, the transfer tube 107T is significantly stretched toward upstream in
Note that the actual length of the transfer tube 107T in
Next, operation of changing the colors of toner transferred by the most-upstream primary transfer section 201, the central primary transfer section 202, and the most-downstream primary transfer section 203 is described with reference to the flowchart of
As illustrated in
Then, the controller 300 of the image forming apparatus 1 determines whether the colors of toner are correctly arranged. When the colors of toner are not correctly arranged, the controller 300 causes an operation display unit to display a message prompting to replace the black (K) toner with the special color toner (steps S2 and S3). Then, the power supply of the image forming apparatus 1 is turned off. The pre-supply reservoir 104K is replaced with the pre-supply reservoir 104T and the image forming device 10K is replaced with image forming device 10T. Then, the power supply of the image forming apparatus 1 is turned on again (steps S4, S5, and S6). Subsequently, the controller 300 of the image forming apparatus 1 determines again whether the pre-supply reservoir 104K has been replaced with the pre-supply reservoir 104T and the image forming device 10K have been replaced with image forming device 10T (step S7). If the replacement has not been performed, the message to replace the black (K) toner with the special color toner is displayed again on the operation display unit (step S8).
In steps S2 and S7, the controller 300 determines whether the black (K) toner and the special color toner are correctly arranged, and the controller 300 also determines whether a correct color such as the transparent color or the white color is set as the special color.
Before the setting of the image forming apparatus 1 is changed, the power supply of the image forming apparatus 1 may be turned off as in step S4 and the arrangement of the toner colors may be changed as in step S5.
As illustrated in
The determination circuit 301 includes a first connector 302, a second connector 303, a third connector 304, and a fourth connector 305. The first connector 302 is connected to the pre-supply reservoir 104K disposed most upstream. The second connector 303 is connected to the pre-supply reservoir 104T disposed most downstream. The third connector 304 is connected to the image forming device 10K disposed most upstream. The fourth connector 305 is connected to the image forming device 10T disposed most downstream.
The pre-supply reservoir 104K includes a circuit board 104K1 connected to the first connector 302, and the pre-supply reservoir 104T includes a circuit board 104T1 connected to the second connector 303. A circuit board 10K1 connected to the third connector 304 is disposed in, for example, a development container of the developing device 6K of the image forming device 10K, and a circuit board 10T1 connected to the fourth connector 305 is disposed in, for example, a development container of the developing device 6T of the image forming device 10T.
The first connector 302, the second connector 303, the third connector 304, and the fourth connector 305 each include multiple switches. The determination circuit 301 can determine whether the black (K) toner or the special color toner is arranged and which special color toner is arranged if the special color toner is arranged, based on a combination of ON and OFF of the switches when the circuit board 104K1, the circuit board 104T1, the circuit board 10K1, and the circuit board 10T1 are connected to the first connector 302, the second connector 303, the third connector 304, and the fourth connector 305, respectively. In the case in which the controller 300 determines only whether the black (K) toner or the special color is arranged without determining which special color toner is arranged, the determination may be made based on whether the feeler 27a and the photosensor 28 are turned on or off.
Further, the controller 300 receives a detection result of the sensor 22. The controller 300 changes the rotation speed of the intermediate transfer belt 2 based on the detection result.
Next, the transfer device 20 according to a modification of the above-described embodiments is described with reference to
As illustrated in
The second contact-and-separation mechanism 92 includes the cam 51. The rotation fulcrum 55a is fixed to the front slider 50 that brings the primary transfer rollers 7C, 7M, and 7Y of the central primary transfer section 202 into contact with and separate from the intermediate transfer belt 2. When the cam 51 rotates to move the front slider 50 to the right in
In the above-described embodiment, the driven roller 55A contacts the intermediate transfer belt 2 when the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are positioned at the contact positions to stretch the intermediate transfer belt 2. In the above-described mode E in which the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the large separation position and the primary transfer rollers 7Y 7M, and 7C of the central primary transfer section 202 are arranged at the contact positions, the primary transfer roller 7T of the most-downstream primary transfer section 203 is separated from the photoconductor 3. Accordingly, the nip pressure of the transfer nips of primary transfer roller 7Y, 7M, and 7C of the central primary transfer section 202 is likely to be small.
In the present modification, the driven roller 55A disposed between the primary transfer roller 7T of the most-downstream primary transfer section 203 and the primary transfer roller 7C disposed immediately upstream from the primary transfer roller 7T contacts the intermediate transfer belt 2 when the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are arranged at the respective contact positions. By so doing, transfer pressure of the transfer nips of the primary transfer rollers 7Y 7M, and 7C of the central primary transfer section 202 can be prevented from being decreased.
In addition, the sensor 22 is disposed between the driven roller 55A and the primary transfer roller 7T. By so doing, the traveling speed of the intermediate transfer belt 2 can be detected in a state in which there is no influence of the vibration of the driven roller 55A to the intermediate transfer belt 2. Thus, the accuracy of the traveling speed of the intermediate transfer belt 2 in the most-downstream primary transfer section 203 can be particularly enhanced.
Next, another embodiment of the present disclosure is described with reference to
As illustrated in
A hole 56b is disposed in the rotator 56. A pin 32e of the front slider 32 is inserted into the hole 56b. The hole 56b has the same height at both ends of the hole 56b in the horizontal direction in
The driven roller 56A has the above-described shape. Accordingly, the driven roller 56A can be separated from the intermediate transfer belt 2 only when the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the small separation position, and the driven roller 56A can be brought into contact with the intermediate transfer belt 2 when the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the large separation position.
In other words, when the primary transfer roller 7T of the most-downstream primary transfer section 203 in
On the other hand, when the primary transfer roller 7T of the most-downstream primary transfer section 203 in
Also in the present embodiment, the driven roller 56A can contact the intermediate transfer belt 2 when the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 are arranged at the contact positions and the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the large separation position.
As a result, the transfer pressure of the transfer nips of the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 can be prevented from being decreased. Further, due to the shape of the hole 56b described above, the driven roller 56A can be separated from the intermediate transfer belt 2 only-when the primary transfer roller 7T of the most-downstream primary transfer section 203 is arranged at the small separation position.
Embodiments of the present disclosure are not limited to the embodiments and modification described above, and various modifications and enhancements are possible without departing from the gist of the present disclosure.
Examples of the recording sheet include, in addition to the sheet P (plain paper), thick paper, a postcard, an envelope, thin paper, coated paper such as coated paper or art paper, tracing paper, an overhead projector (OHP) sheet, a plastic film, prepreg, and copper foil.
In the above-described embodiments of the present disclosure, the primary transferors of all the transfer sections disposed in the transfer device are movable in directions in which the primary transferors contact with or separate from the latent image bearer. However, the embodiments of the present disclosure are not limited to such a configuration. In other words, the primary transfer rollers 7Y, 7M, and 7C of the central primary transfer section 202 may not be moved.
In the above-described embodiments of the present disclosure, the primary transfer roller 7T and the driven rollers 33A and 21A of the most-downstream primary transfer section 203 are moved by the driving force of the common driving source. In some embodiments, each of the primary transfer roller 7T and the driven rollers 33A and 21A of the most-downstream primary transfer section 203 may be moved by the driving force of a different driving source.
In the above-described embodiments of the present disclosure, the distance between the primary transfer roller 7T, which is the primary transferor most downstream in the rotation direction of the intermediate transfer belt 2, and the photoconductor 3T is greater at the large separation position than at the small separation position. However, the primary transfer roller 7T may not be moved when the primary transfer roller 7T is arranged at the small separation position and the large separation position.
In the above description, configurations of the transferor in which the primary transfer rollers of all the primary transfer sections contact with and separate from the corresponding photoconductors have been described. However, at least the primary transfer rollers of the most-downstream primary transfer section and the most-upstream primary transfer section may contact with or separate from the corresponding photoconductors.
Aspects of the present disclosure are, for example, as follows.
In a first aspect of the present disclosure, a transfer device includes an intermediate transferor to rotate,
multiple primary transferors to contact the intermediate transferor,
multiple primary transfer sections, and multiple latent image bearers. The multiple primary transfer sections each has a primary transfer nip between the primary transferor and the latent image bearer with the intermediate transferor interposed between the primary transferor and the latent image bearer.
The multiple primary transfer sections include a most-upstream primary transfer section most upstream in a rotation direction of the intermediate transferor and a most-downstream primary transfer section most downstream in the rotation direction. The most-upstream primary transfer section and the most-downstream primary transfer section are switchable to transfer developer of a special color other than any of yellow, magenta, cyan, and black color.
The primary transferor of the most-upstream primary transfer section and the primary transferor of the most-downstream primary transfer section are disposed to be switchable between a contact position at which the primary transferor contacts the latent image bearer with the intermediate transferor interposed between the primary transferor and the latent image bearer and a separation position at which the primary transferor is separated from the latent image bearer.
Only the primary transfer section that transfers the developer of the special color is arranged at the separation position. Each of the other primary transfer sections is arranged at the contact position to transfer an image.
In the transfer device according to the first aspect, the most-upstream primary transfer section or the most-downstream primary transfer section transfers a developer image of black color.
In the transfer device according to the first or second aspect, the developer transferred in the most-upstream primary transfer section and the developer transferred in the most-downstream primary transfer section are exchangeable with each other.
In the transfer device according to any one of the first to third aspects, the primary transfer section to transfer the developer of the special color is arranged at the separation position and each of at least four other primary transfer sections of the multiple primary transfer sections are arranged at the contact position to transfer an image.
The transfer device according to any one of the first to fourth aspects further includes a sensor between the most-downstream primary transfer section and the primary transfer section immediately upstream from the most-downstream primary transfer section to detect a rotation speed of the intermediate transferor.
The transfer device according to any one of the first to fifth aspects further includes a first tension roller to stretch the intermediate transferor, and
a first movement mechanism to cause a single driving source to move the primary transferor of the most-downstream primary transfer section to the contact position and the separation position and move the first tension roller to a first position, a second position, and a third position.
In the transfer device according to any one of the first to sixth aspects, the first tension roller is disposed downstream from the primary transferor of the most-downstream primary transfer section in the rotation direction of the intermediate transferor and stretches the intermediate transferor at all of the first position, the second position, and the third position of the first tension roller moved by the first movement mechanism.
The transfer device according to any one of the first to seventh aspects further includes a second tension roller between the most-downstream primary transfer section and the primary transfer section immediately upstream from the most-downstream primary transfer section in the rotation direction of the intermediate transferor to stretch the intermediate transferor.
The second tension roller stretches the intermediate transferor in a state in which the primary transferor of the most-downstream primary transfer section is separated from the latent image bearer and the primary transfer section immediately upstream from the most-downstream primary transfer section in the rotation direction of the intermediate transferor contacts the latent image bearer.
The transfer device according to the eighth aspect further includes a sensor between the most-downstream primary transfer section and the second tension roller to detect a rotation speed of the intermediate transferor.
The transfer device according to the eighth or ninth aspect further includes a second movement mechanism to cause the primary transferor of the central primary transfer section immediately upstream from the most-downstream primary transfer section to contact with and separate from the intermediate transferor. The second movement mechanism causes the second tension roller to move in directions in which the second tension roller contacts with and separates from the intermediate transferor.
In the transfer device according to the eighth or ninth aspect, the first movement mechanism causes the second tension roller to move in directions in which the second tension roller contacts with and separates from the intermediate transferor.
In the transfer device according to any one of the second to fourth aspects and the sixth to eleventh aspects, the rotation speed of the intermediate transferor is changed based on a detection result by the sensor.
An image forming apparatus includes the transfer device according to any one of the first to twelfth aspects and the multiple latent image bearers.
The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
Number | Date | Country | Kind |
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2022-091526 | Jun 2022 | JP | national |
2023-060073 | Apr 2023 | JP | national |