JP2006048004A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an opening/closing part openable when a recording material stays while being nipped by a transfer means and a fixing means at the same time, in an image forming apparatus having a transfer means which contacts an image bearing member and conducts transfer, a fixing means which nips and fixes a recording material and an opening/closing part which can be opened and closed with respect to the main body and in which the fixing means is provided. <P>SOLUTION: An image forming apparatus has a transfer means 3 which contacts an image bearing body 2 in a transfer region T and transfers the toner image on the image bearing body 2 to a recording material P; a fixing means 5 which nips the recording material P in a fixing region F and fixes the toner image to the recording material P; and an opening/closing part 35 which can be opened and closed with respect to a main body 30, in which the fixing means 5 is provided, and which moves the fixing means 5 by opening and closing, as the recording material P which stays between the transfer region T and the fixing region F can be removed outside of the image forming device in an open state. It has a separating means 35b which separates the transfer means 3 contacting the image bearing body 2 from the image bearing body 2 when the opening/closing part 35 opens. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to the arrangement of transfer means, fixing means, and the like of an electrophotographic image forming apparatus.

  In recent years, there has been a demand for an image forming apparatus that can easily remove a staying recording material when a jam occurs.

  In order to meet this demand, an opening / closing part that can be opened and closed with respect to the main body of the image forming apparatus is provided. The recording material staying between the transfer means for transferring the toner image on the image carrier to the recording material in the transfer area and the fixing means for fixing the recording material in the fixing area It is removed from the opening / closing part. With this configuration, the recording material can be easily removed out of the image forming apparatus.

  Further, the fixing means is provided in the opening / closing section and moves by opening / closing of the opening / closing section. This configuration prevents the fixing unit from hindering the removal of the recording material. On the other hand, the transfer means is provided in the main body of the image forming apparatus, and the opening / closing portion is reduced in weight.

JP 2001-249522 A JP 2003-156984 A

  However, in the image forming apparatus having the above-described configuration, when the recording material stays in the state of being sandwiched between the transfer unit and the fixing unit at the same time, there is a problem that the opening / closing unit does not open.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image having transfer means for transferring in contact with an image carrier, fixing means for fixing by sandwiching a recording material, and an opening / closing portion that opens and closes the main body and is provided with the fixing means. In the forming apparatus, when the recording material stays in the state of being sandwiched between the transfer unit and the fixing unit at the same time, the opening / closing portion can be opened.

  A typical configuration of the present invention for achieving the above object includes an image carrier, a toner image forming unit that forms a toner image on the image carrier, and a main body of the image forming apparatus. A transfer unit that contacts the image carrier and transfers a toner image on the image carrier to a recording material; and a fixing unit that sandwiches the recording material and fixes the toner image to the recording material in a fixing region; The recording material that can be opened and closed with respect to the main body, is provided with the fixing unit, and is in an open state, so that the recording material staying between the transfer area and the fixing area can be removed out of the image forming apparatus. The image forming apparatus having an opening / closing unit that moves the fixing unit by opening / closing includes a separation unit that separates the transfer unit contacting the image carrier when the opening / closing unit opens. It is characterized by.

  According to the present invention, when the opening / closing part is opened, the transfer part is separated from the image carrier, so that the opening / closing part can be provided even when the recording material stays between the transfer part and the fixing part. I can open it.

  Embodiments of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of an image forming apparatus according to the present embodiment. First, the image forming process will be described with reference to FIG.

  In the image forming apparatus shown in FIG. 1, four photosensitive drums 10a to 10d for forming toner images of respective colors of yellow, magenta, cyan, and black are arranged in parallel. Around the photosensitive drums 10a to 10d, a charger, a developing device, and a cleaner (not shown) are arranged, and these are unitized as process cartridges 1a to 1d as toner image forming means. An intermediate transfer belt 2 as an example of an image carrier is disposed above the process cartridges 1a to 1d so as to be in contact with the photosensitive drums 10a to 10d.

  Each of the photosensitive drums 10a to 10d is charged by a charger (not shown), and an optical image of each color of yellow, magenta, cyan, and black is exposed by the exposure device 6, and the photosensitive drums 10a to 10d are yellow, Magenta, cyan, and black latent images are formed. Each latent image is developed by a developing device to form yellow, magenta, cyan, and black toner images on the photosensitive drums 10a to 10d.

  Along with the rotation of the photosensitive drums 10a to 10d, the toner image arrives at the primary transfer portion where the photosensitive drums 10a to 10d and the intermediate transfer belt 2 are in contact with each other. The toner images are sequentially transferred to the intermediate transfer belt 2 by primary transfer rollers 20a to 20d disposed to face the respective photosensitive drums 10a to 10d.

  The sheets P stored in the feeding cassette 4 are fed one by one by a pickup roller 8 as an example of a feeding and conveying unit, and after the timing is adjusted by a registration roller 9, the sheet P (recording material) is transferred to the unit. The toner image on the intermediate transfer belt 2 is secondarily transferred in the transfer region T all at once by being conveyed to the nip portion constituted by the secondary transfer roller 3 and the intermediate transfer belt 2 as an example. Thereafter, the sheet P on which the toner image has been transferred is conveyed to a fixing device 5 as an example of fixing means, where it is fixed in the fixing region F by receiving heat and pressure. Here, the fixing device 5 includes a roller 5a and a roller 5b (roller pair) that are in contact with each other in the fixing region F and sandwich and convey the sheet P. Further, by rotating a separation lever (fixing member separation means) 53 provided on the roller 5a in the direction of arrow A, the roller 5a is separated from the roller 5b. After fixing, each color toner is melted and mixed and fixed on the sheet P to form a full-color print image, and then the sheet P is discharged as an example of a discharge stacking means by a discharge conveying means 21 provided downstream of the fixing device 5. It is discharged to the discharge tray 7.

  The arrangement of each part in the apparatus will be described. The image forming apparatus according to the present embodiment is arranged from the lower side of the main body 30 to the feeding cassette 4, the exposure device 6, the process cartridges 1a to 1d, the intermediate transfer belt 2, and the discharge tray 7. Are arranged in this order. In the main body 30, a fixed power source 32 and a main electrical board 33 that controls the entire image forming apparatus are arranged. Further, an electrical board 31 for applying a transfer bias to the primary transfer rollers 20 a to 20 d and the secondary transfer roller 3 is disposed above the intermediate transfer belt 2 and below the discharge tray 7. Here, the discharge tray 7 has a curved surface inclined upward from the upstream side toward the downstream side in the discharge direction from the discharge conveyance means 21, and is in a space formed between the discharge tray 7 and the intermediate transfer belt 2. An electrical board 31 is disposed on the front panel. As shown in FIG. 1, when the image forming apparatus is installed, the fixing device 5 is disposed above the secondary transfer roller 3.

  Next, a characteristic configuration of the present embodiment will be described. FIG. 2 is a cross-sectional view showing a state in which the first rotating portion is opened. FIG. 3 is a view for explaining the configuration in the vicinity of the secondary transfer means. In particular, the wire spring 35b provided on the fixing frame 35 pushes the holder 3b holding the secondary transfer roller 3 so that the secondary transfer roller 3 FIG. 3 is a diagram illustrating a state in contact with an intermediate transfer belt. FIG. 4 shows a state in which the holder 3 b that holds the secondary transfer roller 3 is not pressed by the wire spring 35 b provided on the fixing frame 35 and the secondary transfer roller 3 is separated from the intermediate transfer belt 2. FIG. FIG. 5 is a cross-sectional view showing a state in which the second rotating portion is opened, and FIG. 6 is a diagram for explaining a configuration of a power feeding path for the secondary transfer unit.

  As shown in FIG. 2, a fixing frame 35 as an example of a rotating part (opening / closing part) is provided with a fixing device 5 and a part of a paper path C as an example of a sheet conveyance path, and is provided in the main body part 30. The support shaft 101 is pivoted toward the side surface of the apparatus as a fulcrum, and can be opened and closed. Therefore, when the sheet P sent out from the cassette 4 by the pickup roller 8 is jammed during conveyance and stays in the paper path C, or when the sheet P is jammed in the fixing device 5, the transfer area When the sheet P stays between T and the fixing area F, the paper jamming process is performed by opening the fixing frame 35. At this time, when the fixing frame 35 is opened, the fixing device 5 is moved from a position where the fixing device 5 fixes the toner image onto the sheet P while nipping and conveying the sheet P.

  FIG. 3 is a diagram showing a range D in the vicinity of the secondary transfer roller 3 in FIG. As shown in FIG. 3, the secondary transfer roller 3 is rotatably held by a holder 3b and is urged toward the intermediate transfer belt 2 by a compression spring 3a. The secondary transfer roller unit 3, the compression spring 3a, and the holder 3b constitute a secondary transfer roller unit 3c. Further, the secondary transfer roller unit 3c is swingably attached to the apparatus main body by a support shaft 3d. The support shaft 3d is disposed at a position where the secondary transfer roller 3 is separated from the intermediate transfer belt 2 when the secondary transfer roller unit 3c becomes substantially upright due to its own weight when the fixing frame 35 is opened. When the fixing frame 35 is in the closed state, as shown in FIG. 3, the wire spring 35 b provided on the fixing frame 35 pushes the secondary transfer roller unit 3 c, and the secondary transfer roller 3 moves to the intermediate transfer belt 2. Contact. On the other hand, when the fixing frame 35 is in an open state, as shown in FIG. 4, the wire spring 35 b does not press the secondary transfer roller unit 3 c, and the secondary transfer roller 3 moves away from the intermediate transfer belt 2.

  Further, between the secondary transfer roller unit 3c and the fixing frame 35, a reinforcing member 36 that constitutes a part of the main body frame by connecting a main body left side plate and a main body right side plate (not shown) is disposed. That is, the upper end of the fixing frame 35 is higher than the upper surface of the main body 30 and is supported by the lower support shaft 101 so as to be rotatable with respect to the main body (main body) 30. Therefore, when the fixing frame 35 is opened, a large opening is formed in the main body 30 and the strength of the main body frame is insufficient. Therefore, the reinforcement member 36 is provided to compensate for the insufficient strength of the main body frame.

  The reinforcing member 36 has openings 36a at both ends in the longitudinal direction. On the other hand, an “L” -shaped wire spring 35 b as an example of a separation means is fixed to the fixing frame 35 at a position opposite to the opening 36 a of the reinforcing member 36. When the fixing frame 35 is closed, the wire spring 35b urges the holder 3b through the opening 36a, and rotates the secondary transfer roller unit 3c about the support shaft 3d, thereby rotating the secondary transfer roller. 3 is in contact with the intermediate transfer belt 2. On the contrary, when the fixing frame 35 is opened, the secondary transfer roller 3 is separated from the intermediate transfer belt 2.

  With the above configuration, when the fixing frame 35 is opened as shown in FIG. 2, the secondary transfer roller 3 is separated from the intermediate transfer belt 2 to open the paper path C. Therefore, when the sheet P is jammed before and after the nip portion between the secondary transfer roller 3 and the intermediate transfer belt 2, the jamming process can be easily performed.

  If the sheet P stays in the fixing device 5 and a paper jam occurs, when the fixing frame 35 is opened, the secondary transfer roller 3 is separated from the intermediate transfer belt 2 and the paper path C is opened. The sheet P can be pulled out while holding the sheet P in the container 5. That is, the sheet P staying in the fixing region F is sandwiched between the roller 5a and the roller 5b when the fixing frame 35 is changed from the closed state to the opened state.

  Further, as shown in FIG. 5, by operating a roller separation lever 53 provided in the fixing device 5, the rollers 5a and 5b that are in contact with each other are separated. The separation lever 53 rotates in the direction of arrow A with the rotation shaft 53a as a fulcrum to separate the roller 5a and the roller 5b. FIG. 7 shows a state in which the roller 5a and the roller 5b are separated from each other.

  9A and 9B show details of the fixing member separating means for separating the roller 5a and the roller 5b. The fixing member separation means includes a separation lever 53, a rotation shaft 53a, a support member 53b, a pressure lever 53c, and a spring 53d.

  When the separation lever 53 is at the position shown in FIG. 9A, the pressure lever 53c pushes the roller 5a toward the roller 5b by the applied pressure received from the spring 53d supported by the support member 53b. The roller 5a contacts the roller 5b.

  On the contrary, when the separation lever 53 is at the position shown in FIG. 9B, the pressure applied to the pressure lever 53c from the spring 53d is released. At this time, the roller 5a is not pushed from the pressure lever 53c. The roller 5a moves by its own weight, and the roller 5a is separated from the roller 5b.

  If the rollers 5a and 5b are separated from each other, the paper jam processing of the sheet P remaining on the fixing device 5 can be easily performed.

  Further, since the secondary transfer roller unit 3c is positioned with a support shaft 3d provided on the main body 30 as a fulcrum, alignment with the intermediate transfer belt 2 positioned on the main body 30 is ensured with high accuracy as will be described later. Conveyance defects such as skew feeding and skew feeding of the sheet P are reduced, and the conveyance of the sheet P is stabilized.

  Further, as shown in FIG. 5, the discharge tray 7 is configured as a discharge unit 51 as an example of a second rotating portion integrally with the discharge frame 7a. The discharge unit 51 is supported so as to be rotatable with respect to the apparatus main body with a support shaft 100 provided on the side opposite to the fixing frame 35 as a fulcrum. The intermediate transfer belt 2 is engaged with the discharge unit 51 by an engaging portion (not shown). Therefore, when the discharge unit 51 is opened with the support shaft 100 provided on the main body 30 as a fulcrum, the intermediate transfer belt 2 is released in conjunction with the discharge unit 51. Therefore, when the process cartridges 1a to 1d, which are consumables, are exchanged, the process cartridges 1a to 1d can be accessed only by the opening operation of the discharge unit 51.

  In the above, the intermediate transfer belt 2 is configured to rotate in conjunction with the discharge unit 51. However, the intermediate transfer belt 2 can be rotated independently by sharing the support shaft 100 that is the rotation fulcrum of the discharge unit 51. A configuration may be employed, or a rotation fulcrum of the intermediate transfer belt 2 and the discharge unit 51 may be provided separately, and the discharge unit 51 and the intermediate transfer belt 2 may be rotated individually.

  The intermediate transfer belt 2 is stretched by stretching rollers 2e, 2f, and 2g, and a transfer frame 2h for supporting the stretching rollers 2e to 2g and the primary transfer rollers 20a to 20d is disposed. In the transfer frame 2h, a power supply path for applying a transfer bias to the secondary transfer roller 3 is formed by combining a power supply wire, a contact plate, a wire rod, and the like wound around the main body 30 from a fixed power source 32. FIG. 6 shows a power feeding path formed by pressing the compression spring 2i against the contact plate 2j at the wire and the end of the wire in the transfer frame 2h.

  On the other hand, a wire spring 3e as an example of a contact portion with respect to the power feeding path is fixed to the secondary transfer roller unit 3c, and one end of the wire spring 3e comes into contact with the peripheral surface of the shaft portion of the secondary transfer roller 3. The other end of the wire spring 3e has an “L” shape and abuts against the surface of the contact plate 2j in the transfer frame 2h opposite to the pressing portion of the compression spring 2i. Accordingly, when the fixing frame 35 is closed, the secondary transfer roller unit 3c is positioned at a predetermined position by the wire spring 35b, and the L-shaped end portion of the wire spring 3e is pressed against the contact plate 2j, so that the secondary transfer roller 3 is pressed. Is formed. On the contrary, when the fixing frame 35 is opened, the power supply path to the intermediate transfer belt 2 is opened (cut). That is, since the power supply to the secondary transfer roller 3 is immediately cut off when the fixing frame 35 is opened to perform a paper jam processing or the like, it is possible to ensure safety for the operator.

  To summarize the above description, that is, the rotating unit is intended to open the sheet conveyance path for jam processing and to replace the internal unit. Here, there is a demand for the intermediate transfer belt on the apparatus main body side and the secondary transfer roller to come into contact with high positional accuracy.

  Therefore, in the present invention, the fixing device is disposed on the rotating portion side, and the secondary transfer roller is disposed on the apparatus main body side, so that the positional accuracy of the secondary transfer roller can be improved while ensuring the ease of jam processing. It became possible to secure.

  In addition, the secondary transfer roller is provided with a means for separating and contacting the secondary transfer belt in the rotating part, and the secondary transfer roller comes in contact with the opening and closing of the rotating part. However, the sheet conveyance path can be opened, and jamming can be easily performed. If the sheet stays in the fixing unit by providing the fixing unit in the rotating unit, the sheet comes to the fixing unit when the rotating unit is opened. Therefore, it is possible to easily perform the jam processing only by releasing the pressure of the fixing device.

  By the way, although the strength of the opening of the rotating portion tends to be insufficient, if a heavy device such as a fixing device is disposed in the rotating portion, the strength of the main body frame is insufficient. In particular, when the second rotating portion has a support shaft on the opposite side to the rotating portion as in the above-described embodiment, the opening portion is further increased, and the strength of the main body frame is insufficient. However, a reinforcing member cannot be provided in the moving range of the rotating part. On the other hand, since the secondary transfer roller is left on the main body side, the position of the secondary transfer roller cannot be set in the movement range of the rotating portion, and it is necessary to have a retracted shape.

  Therefore, in the present invention, by disposing the reinforcing member between the secondary transfer roller and the rotating portion, the retracted portion of the rotating portion can be minimized. Therefore, it is possible to efficiently provide a reinforcing member that is an opening of the rotating part and outside the moving range, and the apparatus can be downsized while ensuring the strength of the rotating part. Further, the image forming apparatus can be miniaturized by disposing the fixing device supported by the rotating portion so as to cover the secondary transfer roller.

  In addition, by arranging a reinforcing member between the secondary transfer roller and the rotating part, that is, in the vicinity of the secondary transfer roller, the main body frame near the secondary transfer roller is prevented from being deformed even if the rotating part is heavy. In addition, high positional accuracy of the secondary transfer roller can be ensured.

  In this embodiment, the intermediate transfer belt 2 is described as having a substantially horizontal arrangement. However, the intermediate transfer belt 2 is inclined downward toward the secondary transfer roller 3 as shown in FIG. It may be arranged. In this case, the space in the vicinity of the secondary transfer roller 3 is narrowed. However, as described above, the reinforcing member 36 is fixed to the main body left side plate and the main body right side plate, and the secondary transfer roller 3 is supported by the main body. The rigidity of the main body frame can be ensured and the jam handling property of the sheet P is not affected at all.

  The present invention can be used in an image forming apparatus having a rotating portion.

1 is an overall configuration diagram of an image forming apparatus according to an embodiment. It is sectional drawing which shows the state which open | released the 1st rotation part. FIG. 6 is a diagram illustrating the vicinity of the secondary transfer unit and showing the state where the secondary transfer unit is in contact with the image carrier. FIG. 6 is a diagram illustrating a state where the secondary transfer unit is separated from the image carrier. It is sectional drawing which shows the state which open | released the 2nd rotation part. It is a figure explaining the structure of the electric power feeding path | route with respect to a secondary transfer means. It is a figure which shows the state which open | released the 1st rotation part and the roller provided in the fixing device has separated. It is a figure explaining the structure of the image forming apparatus which concerns on another Example. It is a figure explaining the means to space apart the roller of a fixing device.

Explanation of symbols

C: Paper path F: Fixing area P: Sheet (recording material)
T: Transfer areas 1a to 1d ... Process cartridge (toner image forming means)
2 ... Intermediate transfer belt (image carrier)
2h ... transfer frame 2i ... compression spring 2j ... contact plate 3 ... secondary transfer roller (transfer means)
3a ... Compression spring 3b ... Holder 3c ... Secondary transfer roller unit 3d ... Support shaft 3e ... Wire spring 4 ... Feed cassette 5 ... Fixing device (fixing means)
5a, 5b ... Roller (fixing member)
6 ... Exposure device 7 ... Discharge tray 7a ... Discharge frame 8 ... Pickup roller 9 ... Registration roller
10a to 10d ... photosensitive drum
20a-20d ... Primary transfer roller
21… Discharge transport means
30 ... Main unit (main unit)
31… Electronic board
32… Power supply
33… Main electrical circuit board
35… Fixing frame (opening / closing part)
35b ... Wire spring (separating means)
36… Reinforcing member
36a ... opening
51… discharge unit
53 ... Separation lever (fixing member separation means)
53a… Rotating shaft
53b ... Support member
53c… Pressure lever
53d… Spring
100… support shaft
101… Spindle

Claims (4)

An image carrier;
Toner image forming means for forming a toner image on the image carrier;
Provided in the main body of the image forming apparatus,
A transfer means for transferring a toner image on the image carrier to a recording material in contact with the image carrier in a transfer region;
Fixing means for holding the recording material in the fixing region and fixing the toner image to the recording material;
The recording material that can be opened and closed with respect to the main body, is provided with the fixing unit, and is in an open state, so that the recording material staying between the transfer region and the fixing region can be removed out of the image forming apparatus. An image forming apparatus having an opening / closing unit that moves the fixing unit by opening / closing,
An image forming apparatus comprising: a transfer unit that contacts the image carrier when the opening / closing portion is opened; and a separation unit that separates the transfer unit from the image carrier.   The fixing unit includes a pair of fixing members that are in contact with each other and sandwich the recording material in the fixing region, and the recording material staying in the fixing region is changed from a state in which the opening / closing portion is closed to an open state. The image forming apparatus according to claim 1, wherein the image forming apparatus is held between the fixing members.   The image forming apparatus according to claim 2, wherein the fixing unit includes a fixing member separating unit that separates the fixing members in contact with each other.   The image forming apparatus according to claim 3, wherein the transfer unit is positioned with respect to the main body.

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