Image forming apparatus

Abstract

One embodiment of the image forming apparatus includes an apparatus body, a processing unit, and a pressing member. The apparatus body has a transfer belt wound in a ring around a plurality of rollers. The processing unit is configured to be insertable and removable relative to the apparatus body. The processing unit has a photosensitive drum facing the transfer belt when inserted into the apparatus body. The processing unit forms an image on the surface of the photosensitive drum. The pressing member is provided in the apparatus body and has a contact portion and a contact portion. When the processing unit is inserted or removed relative to the apparatus body, the contact portion contacts the processing unit. Through contact with the processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the processing unit.

Description

Technical Field

[0001] Embodiments of the present invention relate to image forming apparatuses such as copiers, printers, and multifunction printers (multi-function printers). Background Technology

[0002] When replacing the processing unit of the image forming apparatus, the transfer belt is separated from the processing unit, the old processing unit is pulled out from the main body of the apparatus, and the new processing unit is inserted into the main body of the apparatus. At this time, in order to make the transfer belt and the processing unit non-contact, one or more rollers wound with the transfer belt are moved away from the processing unit.

[0003] However, when the transfer belt stretches due to aging, it is sometimes impossible to separate the transfer belt from the processing unit even by moving the roller wound with the transfer belt. In this case, when the processing unit is disassembled or assembled relative to the main body of the device, the processing unit may come into contact with the transfer belt and cause the transfer belt to break.

[0004] To prevent such adverse effects, one could consider increasing the movement of the roller wound with the transfer belt or increasing the load on the tension spring that applies tension to the transfer belt. However, increasing the movement of the roller wound with the transfer belt would result in a larger moving mechanism. Furthermore, increasing the load on the tension spring would increase the elongation of the transfer belt.

[0005] Therefore, it is desirable to develop an image forming apparatus that, through a simple structure, avoids contact between the processing unit and the transfer belt when the processing unit is plugged in or removed from the apparatus body. Summary of the Invention

[0006] The image forming apparatus according to the embodiment includes: an apparatus body having a transfer belt wound in a loop around a plurality of rollers; a processing unit configured to be insertable and removable relative to the apparatus body, the processing unit having a photosensitive drum and forming an image on the surface of the photosensitive drum, wherein the photosensitive drum is opposite to the transfer belt when the processing unit is inserted into the apparatus body; and a pushing member disposed in the apparatus body and having a contact portion and a contact portion, wherein when the processing unit is inserted or removable relative to the apparatus body, the contact portion contacts the processing unit, and through contact with the processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the processing unit.

[0007] The image forming apparatus according to the embodiment includes: an apparatus body having a transfer belt wound in a loop around a plurality of rollers; a plurality of processing units configured to be mutually separated along the travel direction of the transfer belt and capable of being inserted and removed relative to the apparatus body, each processing unit having a photosensitive drum and forming an image on the surface of the photosensitive drum, wherein the photosensitive drum is opposite to the transfer belt when the processing unit is inserted into the apparatus body; a moving mechanism for rotating the transfer belt about a downstream side of the travel direction as a fulcrum to separate it from the plurality of photosensitive drums; and a pushing member disposed on the apparatus body corresponding to a first processing unit at the downstream side of the travel direction of the transfer belt, having a contacted portion and a contact portion, wherein when the first processing unit is inserted and removed relative to the apparatus body, the contacted portion contacts the first processing unit, and through contact with the first processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the first processing unit. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an image forming apparatus according to one embodiment.

[0009] Figure 2 It means Figure 1 An enlarged view of the image forming section of an image forming apparatus.

[0010] Figure 3 It means control Figure 1 A block diagram of the control system for the operation of the image forming apparatus.

[0011] Figure 4 Viewed from the inside of the frame Figure 1 A three-dimensional view of the contact protection mechanism of the image forming apparatus.

[0012] Figure 5 Observe along arrow F5 Figure 4 A cross-sectional view of the main structure.

[0013] Figure 6 It is used for explanation Figure 5 A three-dimensional diagram showing the relationship between the upward-pushing component and the transfer belt.

[0014] Figure 7 It means to pull out from the frame. Figure 5 A cross-sectional view of the anti-contact mechanism during the processing of the unit.

[0015] Figure 8 It is used for explanation Figure 7 A three-dimensional diagram showing the relationship between the upward-pushing component and the transfer belt.

[0016] Figure 9 It is used to explain Figure 5A diagram illustrating the action of the anti-contact mechanism when the processing unit is inserted into the frame.

[0017] Figure 10 It is used to explain Figure 5 A diagram illustrating the action of the anti-contact mechanism when the processing unit is inserted into the frame.

[0018] Explanation of reference numerals in the attached figures

[0019] 1. Image forming apparatus; 11. Frame; 17. Image forming unit; 41. Processing unit; 51, 52. Moving mechanism; 60. Anti-contact mechanism; 61. Pushing member; 62. Rib; 63. Plate; 64. Protective sheet; 65. Protrusion; 71, 711, 712, 713, 714. Photosensitive drum; 91. Transfer belt; 93. Primary transfer roller; 95. Tension roller; 97. Moving roller with belt; 98. Pressing roller with belt; 111. Frame; P. Printing medium. Detailed Implementation

[0020] One embodiment of the image forming apparatus includes an apparatus body, a processing unit, and a pressing member. The apparatus body has a transfer belt wound in a ring around a plurality of rollers. The processing unit is configured to be insertable and removable relative to the apparatus body. The processing unit has a photosensitive drum facing the transfer belt when inserted into the apparatus body. The processing unit forms an image on the surface of the photosensitive drum. The pressing member is provided in the apparatus body and has a contact portion and a contact portion. When the processing unit is inserted or removed relative to the apparatus body, the contact portion contacts the processing unit. Through contact with the processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the processing unit.

[0021] Hereinafter, with reference to the accompanying drawings, an image forming apparatus 1 according to one embodiment will be described.

[0022] like Figure 1 As shown, the image forming apparatus 1 has a housing 11. The housing 11 includes a communication interface 12, a system controller 13, multiple paper trays 14, a paper discharge tray 15, a transport unit 16, an image forming unit 17, a fixing unit 18, a scanning unit 19, and a control panel 20. The housing 11 is the main body of the image forming apparatus 1. In the following description, it will be referred to as... Figure 1 The front side of the paper surface is designated as the front side of the image forming apparatus 1, and the opposite side is designated as the rear side. Furthermore, the vertical and horizontal dimensions of the image forming apparatus 1 are defined when viewed from the front side.

[0023] Communication interface 12 is an interface used for communication with other devices. For example, communication interface 12 is used for communication with an upper-layer device, also known as an external device. Communication interface 12 may be composed of, for example, a LAN connector. Communication interface 12 can also communicate wirelessly with other devices according to standards such as Bluetooth (registered trademark) or Wi-Fi (registered trademark).

[0024] The system controller 13 functions as the control unit of the image forming apparatus 1. The system controller 13 is connected to the communication interface 12. The system controller 13 generates a printing job, for example, based on data acquired from an external device via the communication interface 12. The printing job includes data of an image formed on a printing medium P. The image data can be data used to form an image on a single printing medium P, or data used to form images on multiple printing media P. The printing job may also include information indicating whether it is color printing or monochrome printing.

[0025] The system controller 13, which generates the printing job, controls the operation of the transport unit 16, the image forming unit 17, and the fixing unit 18 to form an image of the image data contained in the printing job on the printing medium P. Specifically, the system controller 13 controls the transport unit 16 to transport the printing medium P, the image forming unit 17 to form an image on the printing medium P, and the fixing unit 18 to fix the image on the printing medium P. Thus, the system controller 13 also functions as the engine controller of the image forming apparatus 1.

[0026] The image forming apparatus 1 may also have an engine controller separate from the system controller 13. In this case, the engine controller controls at least one of the following: the transport unit 16 transports the printing medium P; the image forming unit 17 forms an image on the printing medium P; and the fixing unit 18 fixes the image onto the printing medium P. The system controller 13 provides the engine controller with the information required for control in the engine controller.

[0027] Multiple paper trays 14 are boxes for holding printing media P. The paper trays 14 are configured to supply the printing media P from outside the frame 11. For example, the paper trays 14 are configured to be pull out from the frame 11.

[0028] The paper tray 15 is a tray that receives the printing medium P discharged from the image forming apparatus 1.

[0029] The transport unit 16 is a mechanism for transporting the printing medium P within the image forming apparatus 1. For example... Figure 1 As shown, the conveying unit 16 has multiple conveying paths. For example, the conveying unit 16 has a paper feeding conveying path 31 and a paper discharge conveying path 32.

[0030] The paper feeding path 31 and the paper discharge path 32 are composed of multiple rollers and multiple guides (not shown). The multiple rollers rotate using power transmitted from the drive mechanism, thereby conveying the printing medium P. The multiple guides control the conveying direction of the printing medium P conveyed by the rollers.

[0031] The paper feed path 31 picks up the printing medium P from the paper tray 14 and supplies the picked-up printing medium P toward the image forming unit 17. The paper feed path 31 has a plurality of pickup rollers 33 corresponding to each paper tray 14. Each pickup roller 33 picks up the printing medium P from the paper tray 14 and feeds it into the paper feed path 31.

[0032] Paper discharge path 32 is the path through which the printing medium P, on which the image is formed by the image forming unit 17, is discharged from the frame 11. The printing medium P discharged by the paper discharge path 32 is supported by the paper discharge tray 15.

[0033] The image forming unit 17 has a structure for forming an image on the printing medium P. Details of the image forming unit 17 will be described later.

[0034] The fixing unit 18 includes a heating roller 34 and a pressure roller 35. The fixing unit 18 uses the heating roller 34 to heat the printing medium P conveyed on the paper conveying path 32 at a predetermined temperature, and then uses the pressure roller 35 to apply pressure, thereby fixing the toner image transferred to the printing medium P onto the printing medium P.

[0035] The scanning unit 19, which reads the original document and converts it into image data, is located on the upper part of the frame 11. The scanning unit 19 includes an automatic document transport device 21. The scanning unit 19 reads the original document transported by the automatic document transport device 21.

[0036] The control panel 20 includes a touch panel 22 and a keyboard 23. The touch panel 22 is, for example, a device that combines a display such as an LCD or OLED display with a positioning device for detecting touch input. The display shows, for example, images for setting various functions of the image forming apparatus 1 as information to notify the user of the image forming apparatus 1.

[0037] The keyboard 23 has various keys for operation by the user of the image forming apparatus 1. For example, the keyboard 23 has numeric keys, a power key, a paper feed key, and function keys. Each key can also be called a button. In this way, the touch panel 22 and the keyboard 23 function as input devices for the image forming apparatus 1. The display on the touch panel 22 functions as a display device for the image forming apparatus 1.

[0038] Next, the image forming unit 17 will be described.

[0039] like Figure 1as well as Figure 2 As shown, the image forming unit 17 includes a plurality of (four in this embodiment) processing units 41 and a transfer unit 42. The plurality of processing units 41 are arranged below the illustration of the transfer unit 42 along the traveling direction of the transfer belt 91, which will be described later.

[0040] Multiple processing units 41 are units for forming toner images of various colors. Multiple processing units 41 are provided according to each type of toner. For example, multiple processing units 41 correspond to cyan, magenta, yellow, and black toners, respectively. Each processing unit 41 includes a toner cartridge 2 containing a chromatic toner of its corresponding color.

[0041] The multiple toner cartridges 2 and multiple processing units 41 for each color have the same structure. Therefore, the same reference numerals are used to label the same structures, and the structure for only one color is described representatively. It should be noted that... Figure 2 The illustration of the exposure unit 74 of the processing unit 41 is omitted.

[0042] Toner cartridge 2 is a container for holding toner. The toner contained in toner cartridge 2 is supplied to the developer 75. Processing unit 41 includes a photosensitive drum 71 (in... Figure 2 The components include photosensitive drums 711, 712, 713, and 714, a cleaner 72, a charging unit 73, an exposure unit 74, and a developer 75.

[0043] The photosensitive drum 71 (711, 712, 713, 714) is a photosensitive element having a cylindrical drum and a photosensitive layer formed on the outer peripheral surface of the drum. The photosensitive drum 71 rotates at a certain speed in a clockwise direction as shown in the figure by means of power transmitted from the drive mechanism.

[0044] The cleaner 72 has a scraper that contacts the surface of the photosensitive drum 71. The cleaner 72 removes toner residue from the surface of the photosensitive drum 71 by using the scraper.

[0045] The charging unit 73 charges the surface of the photosensitive drum 71 uniformly. For example, the charging unit 73 charges the photosensitive drum 71 to a uniform negative potential by applying a gate bias voltage output from the gate to the photosensitive drum 71. Such a charging unit 73 is also called a charging charger.

[0046] The exposure unit 74 has multiple light-emitting elements. These elements may be, for example, laser diodes (LDs), light-emitting diodes (LEDs), or organic EL (OLEDs). The multiple light-emitting elements are arranged in the main scanning direction, which is parallel to the rotation axis of the photosensitive drum 71. Thus, each light-emitting element is configured to illuminate a point on the photosensitive drum 71.

[0047] The exposure unit 74 forms a latent image of one row on the photosensitive drum 71 by irradiating the surface of the charged photosensitive drum 71 with light from a plurality of light-emitting elements arranged along the main scanning direction. Furthermore, the exposure unit 74 forms multiple latent images on the surface of the rotating photosensitive drum 71 by continuously irradiating light onto the surface of the photosensitive drum 71.

[0048] The developer 75 attaches toner to the photosensitive drum 71. The developer 75 contains the developer, which includes the toner and a carrier. The developer 75 receives toner dispensed from the toner cartridge 2.

[0049] The processing unit 41 operates as follows.

[0050] When light is shone from the exposure unit 74 onto the surface of the photosensitive drum 71, which is charged by the charging unit 73, a latent image is formed. Then, the toner contained in the developer supplied from the developer unit 75 adheres to the latent image formed on the surface of the photosensitive drum 71. Thus, a toner image is formed on the surface of the photosensitive drum 71.

[0051] The transfer unit 42 transfers the toner image formed on the surface of the photosensitive drum 71 onto the printing medium P. The transfer unit 42 includes, for example, a transfer belt 91, a drive roller 92, multiple primary transfer rollers 93, and secondary transfer rollers 94. Figure 2 (Illustrations omitted), tension roller 95, driven roller 96, belt moving roller 97, and belt pressing roller 98.

[0052] The transfer belt 91 is wound in a ring around the drive roller 92, tension roller 95, driven roller 96, belt moving roller 97, and belt pressing roller 98. The inner surface (inner circumferential surface) of the transfer belt 91 is in contact with the aforementioned rollers 92, 95, 96, 97, and 98. The outer surface (outer circumferential surface) of the transfer belt 91 is opposite to the photosensitive drum 71 of the multiple processing units 41 and the secondary transfer roller 94.

[0053] The drive roller 92 rotates using power transmitted from a drive mechanism (not shown). The rotation of the drive roller 92 causes the transfer belt 91 to move in a predetermined direction. Figure 2 (The middle direction is counterclockwise). Multiple rollers 92, 95, 96, 97, and 98, on which the transfer belt 91 is wound, are configured to rotate freely and rotate as the transfer belt 91 is moved by the drive roller 92.

[0054] The tension roller 95 applies force to the transfer belt 91 in a direction that is pressed outwards by a spring (not shown). The tension roller 95 imparts tension to the transfer belt 91 by pressing it from the inside to the outside.

[0055] With moving roller 97 configured in Figure 2The primary transfer roller 93 and tension roller 95 are located opposite the cyan processing unit 41 on the far left. The moving roller 97 is linked to the primary transfer rollers 93 of the three processing units 41 other than the black processing unit.

[0056] The moving roller 97 is configured to move between a position where the transfer belt 91 contacts the photosensitive drums 711, 712, and 713 of the three processing units 41 (excluding the black drum) and a position where the transfer belt 91 is separated from the three photosensitive drums 711, 712, and 713.

[0057] Configuration with pressing roller 98 in ratio with Figure 2 The photosensitive drum 714 of the black processing unit 41 (first processing unit) located on the far right is opposite the primary transfer roller 93 on the upstream side of the transfer belt 91 in the direction of travel. Figure 2 The pressure roller 98 is configured to move between a position where the transfer belt 91 contacts the photosensitive drum 714 for black ink and a position where the transfer belt 91 separates from the photosensitive drum 714.

[0058] Multiple primary transfer rollers 93 are arranged according to each processing unit 41. The multiple primary transfer rollers 93 are positioned opposite to the photosensitive drums 71 (711, 712, 713, 714) of their respective processing units 41. Specifically, the multiple primary transfer rollers 93 are positioned opposite to the photosensitive drums 71 of their respective processing units 41 across the transfer belt 91.

[0059] The transfer roller 93 contacts the inner circumferential surface of the transfer belt 91, causing the transfer belt 91 to shift towards the photosensitive drum 71. Through this shift, the outer circumferential surface of the transfer belt 91 contacts the photosensitive drum 71.

[0060] Secondary transfer roller 94 ( Figure 1 The secondary transfer roller 94 is positioned opposite to the drive roller 92, sandwiching the transfer belt 91 between it and the drive roller 92. The secondary transfer roller 94 contacts the outer peripheral surface of the transfer belt 91, which travels along the circumferential surface of the drive roller 92, and applies pressure to the outer peripheral surface of the transfer belt 91. Through this contact and pressure, the secondary transfer roller 94 adheres tightly to the outer peripheral surface of the transfer belt 91, forming a transfer clamping portion between them.

[0061] The secondary transfer roller 94 and the drive roller 92 are rotated to convey the printing medium P supplied from the paper feed path 31 in a clamping state. As a result, the printing medium P passes through the transfer clamping part. The secondary transfer roller 94 presses the printing medium P, which has passed through the transfer clamping part, against the outer peripheral surface of the transfer belt 91.

[0062] In the transfer unit 42 with the above-described structure, when the outer peripheral surface of the transfer belt 91 contacts the photosensitive drum 71, the toner image formed on the surface of the photosensitive drum 71 is transferred to the outer peripheral surface of the transfer belt 91. For example... Figure 1as well as Figure 2 As shown, when the image forming unit 17 has multiple processing units 41, the transfer belt 91 receives toner images from the photosensitive drums 71 of the multiple processing units 41. The toner images transferred to the outer peripheral surface of the transfer belt 91 are conveyed by the transfer belt 91 to the transfer clamping unit. At this time, if a printing medium P is present in the transfer clamping unit, the toner images transferred to the outer peripheral surface of the transfer belt 91 are transferred to the printing medium P at the transfer clamping unit.

[0063] Here, the moving mechanism of the transfer belt 91 will be explained.

[0064] For example, in order to replace the processing unit 41, the image forming apparatus 1 has a structure that allows the processing unit 41 to be inserted and removed from the housing 11. The insertion and removal operation of the processing unit 41 starts from the front side of the housing 11 ( Figure 1 as well as Figure 2 The image forming apparatus 1 of this embodiment has a configuration that allows the processing unit 41, including the developer 75, to be inserted and removed from the front side of the frame 11.

[0065] When the processing unit 41 is inserted or removed relative to the frame 11, the transfer belt 91 needs to be moved in a direction separate from the processing unit 41 so that the processing unit 41 does not come into contact with the transfer belt 91. In addition, the image forming apparatus 1 moves the transfer belt 91 according to its operating mode.

[0066] For example, in the color mode of forming a color image, such as Figure 1 as well as Figure 2 As shown, the transfer belt 91 is moved to a position where it contacts the photosensitive drums 711, 712, 713, and 714 of all four processing units 41. Furthermore, in monochrome mode for forming a monochrome image, the transfer belt 91 is moved to a position separating it from the photosensitive drums 711, 712, and 713 except for the black photosensitive drum 714. Moreover, during maintenance of the insertion / removal processing unit 41 relative to the housing 11, the transfer belt 91 is moved to a position separating it from all the photosensitive drums 711, 712, 713, and 714.

[0067] like Figure 2 As shown, the moving mechanism of the transfer belt 91 includes: a moving mechanism 51 that links the three primary transfer rollers 93 (excluding the black one) with the belt moving roller 97; and a moving mechanism 52 that links the primary transfer roller 93 for black with the belt pressing roller 98. The moving mechanisms 51 and 52 can be provided on both the front and rear sides of the image forming apparatus 1, or on one of them.

[0068] The moving mechanism 51 has a frame 11 configured to be capable of moving relative to the image forming apparatus 1. Figure 2 The slider 53 moves in the left and right directions, and the rotating arm 54 acts on the moving roller 97. The slider 53 is a series of metal frames arranged above the three processing units 41 other than the black one.

[0069] The movable roller 97 is rotatably mounted on the front end of the support arm 971. The base end of the support arm 971 is pivotally mounted to the frame 11 via a shaft 972. The rotating arm 54 has an operating end that acts on the movable roller 97 and a base end on the slider 53 side. The rotating arm 54 is rotatably mounted to the frame 11 via a shaft 541 between the operating end and the base end. A protrusion 542 is provided at the base end of the rotating arm 54 for embedding a groove 531 into the slider 53.

[0070] The three primary transfer rollers 93, excluding the black roller, are rotatably mounted on the front end of the L-shaped support arm 55. Each support arm 55 has a protrusion 551 located within a cutout 532 in the slider 53 at its other end. Each support arm 55 is rotatably mounted to the frame 11 via a shaft 552 between its front and other ends.

[0071] The moving mechanism 51 moves the transfer belt 91 by sliding the slider 53 in the left-right direction as shown in the figure. In color mode, the moving mechanism 51 moves the transfer belt 91 to... Figure 2 The position shown. When slider 53 is positioned... Figure 2 In this position, the conveyor roller 97 is positioned as shown in the diagram to push the transfer belt 91 outwards, and the three primary transfer rollers 93 are positioned as shown in the diagram to press the transfer belt 91 against the photosensitive drums 711, 712, and 713. In this state, the protrusion 551 at the other end of the support arm 55 supporting the three primary transfer rollers 93 is in a non-contact state relative to the slider 53.

[0072] In monochrome mode, the moving mechanism 51 causes the slider 53 to move from... Figure 2 The slider 53 slides to the right as shown in the diagram. When the slider 53 moves to the right as shown in the diagram, the protrusion 542 that engages with the groove 531 of the slider 53 moves to the right as shown in the diagram, and the rotating arm 54 rotates clockwise around the axis 541 as shown in the diagram. When the rotating arm 54 rotates clockwise as shown in the diagram, the acting end of the rotating arm 54 no longer acts on the moving roller 97, the support arm 971 rotates counterclockwise, and the moving roller 97 moves toward the slider 53.

[0073] Furthermore, when the slider 53 is moved to the right as shown in the figure, the protrusion 551 is pushed to the right by the left edge of the three cuts 532 of the slider 53, and the support arm 55 rotates clockwise around the axis 552. As a result, the three primary transfer rollers 93 move in the direction of separation from the photosensitive drums 711, 712, and 713, and the transfer belt 91 separates from the photosensitive drums 711, 712, and 713. At this time, because the belt pressing roller 98 of the moving mechanism 52 is positioned... Figure 2 The position is pressed and the transfer belt 91 is pressed, so the transfer belt 91 is not separated from the photosensitive drum 714 for black.

[0074] The moving mechanism 52 includes: a support arm 56 that supports a primary transfer roller 93, which is opposite to the black photosensitive drum 714 in such a way that the transfer belt 91 is sandwiched between it and the black photosensitive drum 714; a support arm 57 that supports a belt pressing roller 98; and an actuating arm 58 that acts on the belt pressing roller 98.

[0075] A primary transfer roller 93 is rotatably mounted at the swinging front end of the support arm 56. A pressure roller 98 is rotatably mounted at the swinging front end of the support arm 57. The base ends of the two support arms 56 and 57 are swingably mounted to the frame 11 via the same shaft 59. Furthermore, the two support arms 56 and 57 swing together around the shaft 59. In other words, support arm 56 is driven by support arm 57.

[0076] The actuating arm 58 has an actuating end that acts on the pressing roller 98 and a base end that is rotatably mounted to the frame 11 via a shaft 581. When the actuating arm 58 is rotated to... Figure 2 In the position shown, the pressure roller 98 is pressed by the working end of the working arm 58, pressing the transfer belt 91 against the photosensitive drum 714.

[0077] In other words, in the maintenance mode where the transfer belt 91 is separated from all photosensitive drums 711, 712, 713, and 714, starting from the aforementioned monochrome mode state, the moving mechanism 52 moves the transfer belt 91 in the direction of separation from the photosensitive drum 714. In this case, the moving mechanism 52 moves the actuating arm 58 towards... Figure 2 The middle arm rotates counterclockwise, positioning the actuating arm 58 at its actuating end where it does not act on the pressure roller 98 (not shown). Consequently, the support arm 57 rotates clockwise, the pressure roller 98 moves upward as shown, the support arm 56 rotates clockwise, and the primary transfer roller 93 moves in the direction of separation from the photosensitive drum 714.

[0078] Therefore, the transfer belt 91 moves in the direction of separation from the photosensitive drum 714, becoming separated from all four photosensitive drums 71. In this state, the transfer belt 91 tilts upwards from the driven roller 96 toward the tension roller 95, rotating in the direction of separation from each photosensitive drum 71 with its downstream side in its direction of travel (to the right of the illustration) as the fulcrum. Therefore, when the transfer belt 91 is moved to the maintenance position, the distance between the black photosensitive drum 714 and the transfer belt 91 is the shortest compared to other colors.

[0079] Next, the main circuit structure of the image forming apparatus 1 will be described.

[0080] like Figure 3 As shown, the image forming apparatus 1 is configured with a circuit by connecting the communication interface 12, the image forming unit 17, the fixing unit 18, the scanning unit 19, the control panel 20, and the motor 30 to the system controller 13 via signal lines.

[0081] The system controller 13 includes a processor 131, a ROM (Read Only Memory) 132, a RAM (Random Access Memory) 133, and an auxiliary storage device 134. The system controller 13 forms a computer by connecting the processor 131, ROM 132, RAM 133, and auxiliary storage device 134 with signal lines.

[0082] The processor 131 is equivalent to the central part of the aforementioned computer. The processor 131 controls the various components according to the operating system or application programs to perform various functions as the image forming apparatus 1. The processor 131 is, for example, a CPU (Central Processing Unit).

[0083] ROM 132 and RAM 133 correspond to the main storage portion of the aforementioned computer. ROM 132 is a non-volatile storage area, while RAM 133 is a volatile storage area. ROM 132 stores the operating system or application programs. Additionally, ROM 132 stores data required by the processor 131 for controlling various components. RAM 133 serves as a working area for data appropriately rewritten by the processor 131. RAM 133, for example, has a working area for storing image data.

[0084] Auxiliary storage device 134 corresponds to the auxiliary storage section of the computer described above. As auxiliary storage device 134, known storage devices such as EEPROM (Electric Erasable Programmable Read-Only Memory), HDD (Hard Disc Drive), or SSD (Solid State Drive) can be used alone, or a combination of several of them can be used. Auxiliary storage device 134 stores data used by processor 131 during various processes, and data generated by the processes in processor 131. Auxiliary storage device 134 may also store application programs.

[0085] The system controller 13 is connected via signal lines to the toner cartridge 2, photosensitive drum 71, cleaner 72, charging unit 73, exposure unit 74, developer 75, and transfer unit (transfer belt 91, drive roller 92, primary transfer roller 93, secondary transfer roller 94) 42 of the image forming unit 17. Thus, the system controller 6 controls the toner cartridge 2, photosensitive drum 71, cleaner 72, charging unit 73, exposure unit 74, developer 75, transfer unit 42, and fixing unit 18 of each processing unit 41 to form an image on the printing medium P.

[0086] The motor 30 includes: a first motor 301 for driving the conveyor section 16; a second motor 302 for driving the photosensitive drum 71 to rotate; a third motor 303 for driving the drive roller 92 to rotate; and a fourth motor 304 for moving mechanisms 51 and 52 for moving the transfer belt 91.

[0087] The second motor 302 is provided in multiple ways corresponding to the photosensitive drum 71 of each of the multiple processing units 41. The fourth motor 304 is provided in corresponding ways to the moving mechanism 51 and the moving mechanism 52. The motor 30 may also include a motor for a driving mechanism other than the aforementioned driving mechanisms. The motor 30 may be, for example, a brushless motor. The motor 30 may also be a brushed motor.

[0088] When the rotational force of the first motor 301 is transmitted to the conveyor section 16 by the drive mechanism, the printing medium P taken from the paper tray 14 is conveyed at a predetermined speed in the paper feeding conveyor path 31 and the paper discharge conveyor path 32. When the rotational force of the second motor 302 is transmitted to the photosensitive drum 71 by the drive mechanism, the photosensitive drum 71 rotates at a predetermined speed. When the rotational force of the third motor 303 is transmitted to the drive roller 92 by the drive mechanism, the transfer belt 91 is conveyed at a predetermined speed.

[0089] Therefore, during the transport of a printing medium P, an image is formed on the printing medium P when the photosensitive drum 71 rotates once and the transfer belt 91 rotates once. That is, one image formation is performed. Thus, the image forming speed of the image forming apparatus 1 is determined by the transport speed of the printing medium P, the rotation speed of the photosensitive drum 71, and the transport speed of the transfer belt 91.

[0090] The system controller 13 can adjust the image forming speed of the image forming apparatus 1 by controlling the rotational force of the motor 30. That is, the system controller 13 can adjust the image forming speed of the image forming apparatus 1 by controlling the rotational forces of the first motor 301, the second motor 302, and the third motor 303 respectively.

[0091] Next, refer to Figures 4-9 To explain the anti-contact mechanism 60 that prevents the processing unit 41 from contacting the transfer belt 91 when the processing unit 41 is inserted or removed relative to the frame 11.

[0092] For example, when replacing the processing unit 41, the existing old processing unit 41 is removed from the housing 11, and a new processing unit 41 is inserted into the housing 11 in its place. As described above, the replacement operation of the processing unit 41 is performed with the image forming apparatus 1 switched to maintenance mode, thus separating the transfer belt 91 from the plurality of photosensitive drums 71. This prevents the processing unit 41 from contacting the transfer belt 91 when it is inserted or removed.

[0093] However, in maintenance mode, when the four primary transfer rollers 93 are separated from the photosensitive drums 711, 712, 713, and 714, and the belt moving roller 97 and belt pressing roller 98 are moved upwards to avoid contact, fewer components push the transfer belt 91 from the inside out, resulting in weaker tension on the transfer belt 91. Therefore, if the transfer belt 91 elongates or the force applied to the tension roller 95 weakens over time, the transfer belt 91 may become loose. In this case, even if the transfer belt 91 is moved to the maintenance position, it is possible that the transfer belt 91 may not be fully separated from the processing unit 41.

[0094] In particular, since the distance between the photosensitive drum 714 for black and the primary transfer roller 93 is the shortest when the transfer belt 91 is moved to the maintenance position compared to other colors, the transfer belt 91 can easily come into contact with the photosensitive drum 714 for black. Therefore, the anti-contact mechanism 60 can be provided corresponding to all four processing units 41 as in this embodiment, but it is also possible to provide the anti-contact mechanism 60 only in the processing unit 41 for black.

[0095] Assuming that the processing unit 41 is inserted or removed relative to the frame 11 while the transfer belt 91 is in contact with the processing unit 41, the processing unit 41 may slide into contact with the transfer belt 91. Since the insertion or removal of the processing unit 41 relative to the frame 11 is performed manually, it is not easy to move the processing unit 41 horizontally and vertically relative to the frame 11. Furthermore, due to manufacturing errors, it is difficult to move the processing unit 41 vertically. Therefore, when inserting or removing the processing unit 41 relative to the frame 11, it is desirable to reliably separate the transfer belt 91 from the processing unit 41 regardless of its orientation.

[0096] The image forming apparatus 1 of this embodiment includes an anti-contact mechanism 60, which allows the processing unit 41 to be inserted or removed relative to the frame 11 even when the transfer belt 91 has become loose due to aging, even when the transfer belt 91 is moved to the maintenance position, without causing the processing unit 41 to come into contact with the transfer belt 91. In this embodiment, multiple anti-contact mechanisms 60 are provided corresponding to the processing units 41 of each color (four in this embodiment).

[0097] The anti-contact mechanism 60 can be provided on both the front and rear sides of each processing unit 41. In this embodiment, the anti-contact mechanism 60 is provided only on the front side of each processing unit 41. If the anti-contact mechanism 60 is provided on the front side, it is more effective to prevent the front end of the processing unit 41 in the insertion direction from contacting the transfer belt 91 when the processing unit 41 is inserted into the frame 11. Since the multiple anti-contact mechanisms 60 have approximately the same structure, the description here mainly focuses on the anti-contact mechanism 60 provided on the front side of the black processing unit 41, and the description of the mechanisms for other colors is omitted.

[0098] like Figure 4 As shown, the anti-contact mechanism 60 includes: an upward pushing member 61 (pressing member) rotatably mounted on a frame 111 of the housing 11; and a rib 62 provided on the processing unit 41. The frame 111 is a part of the housing 11 that forms part of the housing 11 opposite to the front side of the transfer unit 42, and extends in the left-right direction. Figure 4 The illustration of the transfer unit 42 is omitted, as are the illustrations of the three processing units 41 other than the black processing unit 41. Furthermore, regarding the anti-contact mechanism 60 other than the black processing unit, only the push-up member 61 is shown.

[0099] like Figure 5As shown, the pusher member 61 has a plate 63 that is bent into a generally Z-shape at two points, and a rectangular protective piece 64 (contact portion) attached to a portion of the surface of the plate 63. The plate 63 has a protrusion 65 (contacted portion) integrally formed on its lower surface near the rotating front end, which slides in contact with the rib 62 of the processing unit 41. A plurality of pusher members 61 are arranged along the traveling direction of the transfer belt 91.

[0100] The material of plate 63 and protrusion 65 should preferably be a material with a low coefficient of dynamic friction relative to the rib 62 of processing unit 41, and various materials such as metal and resin can be used. Since the protective sheet 64 is provided on the surface portion of plate 63 where the push member 61 contacts the transfer belt 91, its material should preferably be a soft material that is difficult to damage the transfer belt 91 when in contact with it.

[0101] The push member 61 is mounted on the frame 111 in a rotatable manner via the shaft 66. The shaft 66 extends along the long side of the frame 111, i.e., in the left-right direction. The shaft 66 is located at the base end of the plate 63, which serves as the center of rotation of the push member 61.

[0102] A stop (not shown) is provided on frame 111 to hold the push member 61 in the illustrated position. The stop locks the push member 61, which, due to its own weight, intends to rotate clockwise around axis 66, into the illustrated position. That is, the push member 61 cannot rotate clockwise from the illustrated position, but can rotate counterclockwise. The push member 61 can also be forced clockwise by a spring (not shown).

[0103] The push-up member 61 extends from its base end, on which the shaft 66 is provided, toward the rear of the image forming apparatus 1. The plate 63 of the push-up member 61 has: a first portion 631 on the base end side, having the shaft 66; a third portion 633 on the front end side, having a protrusion 65; and an inclined second portion 632 connecting the first portion 631 and the third portion 633. The rear end of the first portion 631 is located above and forward of the front end of the third portion 633. The second portion 632 slopes downward from the rear end of the first portion 631 toward the front end of the third portion 633. The first portion 631 and the third portion 633 are in the state where the processing unit 41 is inserted into the frame 11. Figure 4 as well as Figure 5 It is roughly horizontally configured in the state shown.

[0104] Rib 62 extends along the long side of processing unit 41, i.e., along the front-to-back direction of processing unit 41. Rib 62 is integrally protruding above the cleaner 72 of processing unit 41 on the upper surface of frame 411 of processing unit 41. Rib 62 is positioned to slide in contact with the protrusion 65 of push member 61 when processing unit 41 is inserted or removed relative to frame 11.

[0105] An inclined sliding surface 621 is provided at the front end of the rib 62. An upper end surface 622 is provided continuously from the sliding surface 621 at the rear side of the rib 62. The sliding surface 621 and the upper end surface 622 are located on the surface of the rib 62. The sliding surface 621 slopes downwards from the front end of the upper end surface 622 of the rib towards the upper surface of the frame 411.

[0106] With the processing unit 41 inserted into the frame 11 ( Figure 5 In the state shown, the sliding surface 621 is positioned slightly separated from the protrusion 65 of the push member 61 on the rear side, such that the rib 62 is not in contact with the push member 61. The upper end surface 622 of the rib 62 is a flat surface that is arranged approximately horizontally when the processing unit 41 is inserted into the frame 11.

[0107] like Figure 6 As shown, with the processing unit 41 inserted into the frame 11, the push member 61 is in a non-contact state relative to the transfer belt 91 of the transfer unit 42. That is, in this state, there is a gap between the protective sheet 64 affixed to the upper surface of the third portion 633 of the push member 61 and the transfer belt 91. In other words, the rib 62 has a length that is in a non-contact state with the push member 61 when the processing unit 41 is inserted into the frame 11.

[0108] If from Figures 4-6 The state shown causes the processing unit 41 to move forward and begin the action of pulling the processing unit 41 out of the housing 11. Figure 7 as well as Figure 8 As shown, the protrusion 65 of the upward pushing member 61 presses against the upper end face 622 of the rib 62, and the upward pushing member 61 rotates slightly counterclockwise about the axis 66. At this time, firstly, the protrusion 65 of the upward pushing member 61 contacts the sliding surface 621 of the rib 62 and slides in contact, and the protrusion 65 is pushed upward little by little while moving along the sliding surface 621. Then, after the protrusion 65 contacts the upper end face 622 of the rib 62, the rotation of the upward pushing member 61 stops and the posture of the upward pushing member 61 is maintained.

[0109] When the upward pushing component 61 rotates, as Figure 7 as well as Figure 8As shown, the protective sheet 64 contacts the transfer belt 91, and the third portion 633 of the push member 61 partially lifts the transfer belt 91. By changing the protrusion height of the protrusion 65 of the push member 61, the lifting amount of the end of the transfer belt 91 lifted by the push member 61 can be set to a desired amount. The protective sheet 64 of the push member 61 partially contacts the vicinity of the front edge of the transfer belt 91, and the front end of the transfer belt 91 is partially lifted.

[0110] As described above, when the processing unit 41 is pulled out of the housing 11, by pushing the front end of the transfer belt 91 near the processing unit 41 away from the processing unit 41, it is possible to at least prevent the front end of the transfer belt 91 from contacting the processing unit 41.

[0111] like Figure 9 as well as Figure 10 As shown, a sliding surface 623 is provided at the rear end of the rib 62 on the upper surface of the frame 411 of the processing unit 41, similar to the front end. The sliding surface 623 is continuous with the upper end face 622 of the rib 62 and slopes downward toward the upper surface of the frame 411 from the rear end of the upper end face 622 of the rib 62. The sliding surface 623 is positioned at the point where it first contacts the protrusion 65 of the push member 61 when the processing unit 41 is initially inserted into the frame 11.

[0112] like Figure 9 As shown by the arrow, when the processing unit 41 is inserted into the frame 11, the front end of the protrusion 65 of the push member 61 first contacts the sliding surface 623 of the rib 62. When the processing unit 41 is further inserted, the protrusion 65 receives a reaction force from the sliding surface 623, and is pushed upward while sliding in contact with the sliding surface. As a result, the push member 61 rotates counterclockwise as shown in the figure. Then, the protective plate 64 of the push member 61 contacts the lower surface of the transfer belt 91, and the portion near the front edge of the transfer belt 91 is as shown. Figure 10 It is shown to be slightly raised upwards.

[0113] In this way, by inserting the processing unit 41 into the housing 11, the front end of the transfer belt 91 is lifted away from the processing unit 41 near the photosensitive drum 71, thereby preventing the processing unit 41 from contacting the transfer belt 91. For example, even if the transfer belt 91 is slack, it is possible to prevent the processing unit 41 from colliding with the front edge of the transfer belt 91.

[0114] Upon insertion of the processing unit 41, when the front end of the protrusion 65 contacts the upper end face 622 of the rib 62, the rotation of the upward pushing member 61 stops, and it remains stationary. Figure 10 The state is maintained until the processing unit 41 is inserted into the housing 11. Then, when the processing unit 41 is fully inserted into the housing 11, as... Figure 4as well as Figure 5 As shown, the protrusion 65 of the push member 61 disengages from the rib 62, and the push member 61 becomes non-contact with the transfer belt 91.

[0115] As described above, according to this embodiment, corresponding to the processing units 41 of each color, a push-up member 61 is mounted on the frame 111 of the housing 11. When the processing units 41 of each color are inserted or removed relative to the housing 11, the protrusion 65 of the push-up member 61 slides into contact with a portion (rib 62) of the processing unit 41. Therefore, according to this embodiment, by simply providing an anti-contact mechanism 60 (push-up member 61 and rib 62) with a simple structure, it is possible to prevent the processing unit 41 from contacting the transfer belt 91 during changeover operations.

[0116] While several embodiments have been described, these embodiments are provided by way of example only and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and likewise within the scope of the invention as described in the claims and its equivalents.

[0117] For example, in the above embodiment, the push member 61 of the anti-contact mechanism 60 is formed by bending a rectangular plate into a roughly Z-shaped form, but it is not limited to this, and the shape of the push member 61 can be any shape. The push member 61 can be, for example, a spring member with one end fixed to the frame 111, and does not necessarily have to be configured to rotate relative to the frame 111. The push member 61 only needs to be able to push the printing tape 91 away from the processing unit 41 by utilizing the reaction force received from the rib 62 when in contact with the rib 62.

[0118] For example, the shape of the pusher member 61 is not limited to Figures 4 to 10 The shape shown. For example, the first portion 631 may not exist between the shaft 66 of the pushing member 61 and the second portion 632. That is, the shaft 66 and the second portion 632 may also be continuous.

[0119] Furthermore, in the aforementioned upward pushing member 61, for example, Figure 10 As shown, the distance between the protrusion 65 (force point) receiving the reaction force from the rib 62 and the shaft 66 (fulcrum) which is the center of rotation, and the distance between the protective plate 64 (near the front end) that allows the pushing member 61 to contact the transfer belt 91 and the shaft 66 are approximately the same. However, the distance between the protrusion 65 and the shaft 66, and the distance between the part that contacts the transfer belt 91 and the shaft 66, can be changed to the desired ratio.

[0120] Furthermore, the protrusion height of the protrusion 65 of the push member 61 can be selected in various ways. For example, the height of the protrusion 65 of the push member 61 can be different depending on the color of the processing unit 41 on which the anti-contact mechanism 60 is provided. In this case, as described above, since the black processing unit 41 poses a higher risk of contact with the transfer belt 91 compared to other colors, the protrusion 65 of the push member 61 corresponding to the black processing unit 41 can be made the highest.

[0121] In addition, in the above embodiment, an anti-contact mechanism 60 is used, which is constructed such that the protrusion 65 of the push member 61 mounted on the frame 111 contacts the rib 62 provided on the frame 411 of the processing unit 41. However, the rib 62 is not a necessary structure. The end of the transfer belt 91 can also be lifted by sliding contact between the protrusion 65 of the push member 61 and a part of the frame 411 of the processing unit 41.

[0122] Furthermore, the sliding surfaces 621 and 623 at the ends of the ribs 62 along the insertion / removal direction of the processing unit 41 are not limited to the shapes described above, and may also be curved into a dome shape or the like. Alternatively, the sliding surfaces 621 and 623 of the ribs 62 may not be provided.

Claims

1. An image forming apparatus comprising: The main body of the device includes a transfer belt, which is wound in a loop around multiple rollers; The processing unit is configured to be insertable and removable relative to the device body. The processing unit has a photosensitive drum and forms an image on the surface of the photosensitive drum. When the processing unit is inserted into the device body, the photosensitive drum is opposite to the transfer belt. The moving mechanism causes the transfer belt to rotate around the downstream side of the traveling direction as a fulcrum, thus separating it from the photosensitive drum; as well as A pushing member, disposed on the main body of the device, has a contacted portion and a contact portion. When the processing unit is inserted or removed relative to the main body of the device, the contacted portion contacts the processing unit, and through contact with the processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the processing unit. The pushing member is configured in a non-contact state relative to the transfer belt when the processing unit is inserted into the main body of the device and the contacted part is not in contact with the processing unit.

2. The image forming apparatus according to claim 1, wherein, The processing unit has a frame that supports the photosensitive drum in a rotatable manner. The frame has a rib extending in the insertion / removal direction of the processing unit at the position where it contacts the contacted portion of the pushing member when the processing unit is inserted or removed relative to the device body.

3. The image forming apparatus according to claim 2, wherein, When the processing unit is inserted into the main body of the device, the rib and the pushing member are in a non-contact state.

4. The image forming apparatus according to claim 1, wherein, The processing unit can be inserted into or removed from the front of the device body relative to the device body. The image forming apparatus has the pushing member on the front side of the apparatus body.

5. An image forming apparatus comprising: The main body of the device includes a transfer belt, which is wound in a loop around multiple rollers; Multiple processing units are configured to be inserted into and removed from the device body, separated from each other along the travel direction of the transfer belt. Each processing unit has a photosensitive drum and forms an image on the surface of the photosensitive drum. When the processing unit is inserted into the device body, the photosensitive drum is opposite to the transfer belt. A moving mechanism causes the transfer belt to rotate about the downstream side of the travel direction as a fulcrum, thereby separating it from the plurality of photosensitive drums; as well as A pushing member, corresponding to the first processing unit on the downstream side of the travel direction of the transfer belt, is disposed on the device body and has a contacted portion and a contact portion. When the first processing unit is inserted or removed relative to the device body, the contacted portion contacts the first processing unit, and through contact with the first processing unit, the contact portion contacts the transfer belt, pushing the transfer belt away from the first processing unit. The pushing member is configured in a non-contact state relative to the transfer belt when the first processing unit is inserted into the main body of the device and the contacted part is not in contact with the first processing unit.

6. The image forming apparatus according to claim 5, wherein, The first processing unit has a frame that supports the first photosensitive drum as a rotatable structure. The frame has a rib extending in the insertion / removal direction of the first processing unit at the position where it contacts the contacted portion of the pushing member when the first processing unit is inserted or removed relative to the device body.

7. The image forming apparatus according to claim 6, wherein, When the first processing unit is inserted into the main body of the device, the rib and the pushing member are in a non-contact state.

8. The image forming apparatus according to claim 5, wherein, The first processing unit can be inserted into or removed from the front of the device body relative to the device body. The image forming apparatus has the pushing member on the front side of the apparatus body.

Images