JP2006071736A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which consideration is paid for a high speed, small size and for high definition, and energy saving and operability as well, and jam processing on the periphery, etc., of a fixing device and maintenance are facilitated. <P>SOLUTION: The image forming apparatus is provided with an image creation engine 2 for forming a toner image, a recording material conveyance system 3 which has a recording material supply section 3a above the image creation engine 2, and ejects and stores the recording material to a recording material ejection section 3c through a conveyance path 3b while the recording material supplied from the recording material supply section 3 a moves across the image creation engine 2 and the recording material supply section 3a after passing through a transfer area of the image creation engine 2, a fixing device 4 which is disposed in part of the conveyance path 3b of the recording material conveyance system 3, and fixes a toner image transferred to the recording material at a transfer area of the image creation engine 2, and a fixing conveyance unit 5 which is provided with the whole or a portion of respective nip conveyance members for nipping and conveying the recording materials before and after at least the fixing device 4 and the fixing device 4 on a common mount, and moves drawably out of an apparatus main part 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system, an electrostatic recording system, or the like, and in particular, records after an image formed on an image carrier is once transferred to an intermediate transfer body. The present invention relates to an improvement in an intermediate transfer type image forming apparatus that performs batch transfer onto a material.

Conventionally, as this type of intermediate transfer type image forming apparatus, each color component toner image formed on a photosensitive member or the like is sequentially primary transferred to an intermediate transfer body, and the multicolor toner image on the intermediate transfer body is transferred to a secondary transfer apparatus. Are known to be collectively transferred onto paper. In addition, in such a color image forming apparatus, in recent years, there is a great demand for speeding up, downsizing, and energy saving.
For speeding up, a tandem configuration in which the image forming units for each color are arranged in parallel on the intermediate transfer belt is effective. However, the image forming units are arranged in parallel and a fixing device is arranged on the extension. The configuration described above has a problem that the apparatus becomes large.

Japanese Patent No. 3470696 (Embodiment of the Invention, FIG. 1) JP-A-4-274264 (Example, FIG. 1)

  As countermeasures against the enlargement of the apparatus, for example, as shown in FIG. 15, the intermediate transfer belt 501 is disposed obliquely, the image forming units 502 (502a to 502d) are shortened and arranged in parallel, and the intermediate transfer is performed. By arranging a fixing device 504 with a heat reflecting plate (not shown) and an exhaust device (not shown) below the belt 501, a configuration of a miniaturized device has been proposed (see, for example, Patent Document 1). ).

However, in such a configuration, the toner images formed on the intermediate transfer belt 501 by the image forming units 502 (502a to 502d) are devised by devising the arrangement of the batch transfer unit 503 and the fixing device 504. The image may be quickly transferred onto the sheet (by the batch transfer unit 503), and the image blur and the increase in size of the apparatus due to the scattering of the toner image on the intermediate transfer belt 501 can be solved. Since (502a to 502d) are arranged on the upper portion of the intermediate transfer belt 501, if toner floats due to development or the like, there is a concern that the intermediate transfer belt 501 may be directly affected or internal contamination may occur. Further, since the heat of the fixing device 504 is discharged outside the apparatus by the exhaust device, there is no concern that the heat of the fixing device 504 immediately affects the image formation, but it is difficult to say that the energy efficiency of the fixing device 504 is good. Further, when the apparatus is used for a long time with this configuration, the heat of the fixing device 504 affects the upper image forming unit 502, and there remains a concern of causing image defects.
In addition, in such a configuration, the sheet tray is generally arranged below the image forming unit 502 because the sheet is necessarily passed through the lower batch transfer unit 503, and when the sheet is supplied to the sheet tray. It is difficult to say that it is a user-friendly device that requires squatting, bending the waist, etc.

  On the other hand, from the viewpoint of operability, a configuration in which the paper tray is disposed above is proposed in, for example, Patent Document 2, but in this case, the paper transport path is a so-called “S-shape”, and the paper operation starts from the printing operation. There is a problem that it takes a long time to discharge. Further, since the paper discharge is normally performed at the lower part of the apparatus, the operability of taking out the paper from the discharge tray is worsened.

  The present invention has been made in order to solve the technical problems as described above, and has high speed, small size, high image quality, energy saving and operability, and is capable of jamming around the fixing device. An object of the present invention is to provide an image forming apparatus that facilitates maintenance.

  That is, according to the present invention, as shown in FIGS. 1A and 1B, an image forming engine 2 that forms a toner image and transfers the toner image to a recording material at a transfer portion, and an upper portion of the image forming engine 2. The image forming engine 2 and the recording medium 2 are provided after the recording material supplied from the recording material supply unit 3a passes through a transfer portion with the image forming engine 2. A recording material conveyance system 3 that discharges and stores the recording material in the recording material discharge unit 3c through a conveyance path 3b that crosses between the recording material supply unit 3a and a part of the conveyance path 3b of the recording material conveyance system 3 is disposed. The fixing device 4 that fixes the toner image transferred to the recording material at the transfer portion of the image forming engine 2 and all or one of the nip conveying members that nip and convey the recording material at least before and after the fixing device 4. And the fixing device 4 are provided on a common base, Is characterized in further comprising a fixing conveyance unit 5 to move can be pulled out from Okimoto body 1.

In such technical means, the image forming engine 2 that is the subject of the present application is not particularly limited in the method of forming an image, and an image forming method such as an electrophotographic method or an electrostatic recording method may be appropriately selected. Moreover, either color or monochrome may be used.
The image forming engine 2 according to the present invention includes an image forming unit that forms and supports a toner image, and an intermediate transfer member that temporarily conveys and holds the toner image from the image forming unit. Is disposed below the intermediate transfer member, it is possible to prevent in-machine contamination due to toner floating or the like in the image forming unit. Further, the distance from the image forming unit to the transfer site can be shortened, the toner image holding time on the intermediate transfer member can be shortened, toner scattering from the intermediate transfer member can be suppressed, and the image quality can be improved. Further, the intermediate transfer member may be either a belt shape or a drum shape, but a belt shape is preferable from the viewpoint of freedom of layout and miniaturization. The image forming unit includes an image carrier that forms a toner image, and the number thereof is not particularly limited. However, when configuring a color image forming apparatus, it may be configured in a tandem type from the viewpoint of speed and the like. preferable.

  Further, the recording material supply unit 3a may be disposed at least above, and the number thereof is not particularly limited. For example, another recording material supply unit 3a is disposed below the image forming engine 2 or the like. There is no problem. As described above, in the present invention, since the recording material supply unit 3a is provided on the upper side, an image forming apparatus that can be operated in an easy posture when supplying the recording material to the recording material supply unit 3a, that is, a user-friendly image forming apparatus. It becomes possible. For example, an image reading device or the like may be mounted above the recording material supply unit 3a disposed above the image forming engine 2.

The recording material conveyance system 3 in the present invention includes a recording material supply unit 3a, a recording material discharge unit 3c, and a recording material conveyance path 3b for conveying the recording material from the recording material supply unit 3a to the recording material discharge unit 3c. The Here, the conveyance path 3b of the recording material means a path for conveying the recording material, and is normally partitioned by a conveyance guide member, and for example, a conveyance guide member such as a nip conveyance member or a conveyance guide is appropriately disposed.
Further, the arrangement position of the recording material discharge portion 3c in the present invention is not particularly limited, and may be any position where the recording material conveyed through the recording material conveyance path 3b is discharged and accommodated. In the present invention, since the recording material discharge portion 3c is also disposed above the image forming engine 2, the posture of taking out the recording material discharged and accommodated in the recording material discharge portion 3c becomes easy, and the take-out operability is also improved. improves.

The fixing device 4 according to the present invention includes a heating unit for fixing the toner image. The heating unit may be a contact heating method, a non-contact heating method, or the like, for example, an electromagnetic induction heating method. And so on.
Further, in the present invention, the fixing device 4 can be disposed near the center of the image forming apparatus (the apparatus main body 1), and compared with an aspect in which the fixing device 4 is disposed near the housing side wall of the image forming apparatus. The influence of outside air at the time of fixing can be reduced, and the fixing device 4 can be effectively used without releasing the heat, thereby saving energy accordingly. If a heat shield member is provided around the fixing device 4, it is possible to further prevent the heat from being discharged from the fixing device 4 and to further save energy.

The fixing and conveying unit 5 in the present invention is provided on a common gantry with all or a part of each nip conveying member that is positioned at least before and after the fixing device 4 and nip conveys the recording material, and the fixing device 4. It is configured to move so as to be able to be pulled out from the apparatus main body 1, and appropriately includes a fixing device 4, for example, a nip conveying member that forms an upstream transfer portion of the fixing device 4 and a downstream nip conveying member. Further, for example, a nip conveying member on the upstream side of the transfer site may be included.
By pulling out such a fixing conveyance unit 5 from the apparatus main body 1, visibility around the fixing device 4 is improved, and jam handling property, maintenance property, and the like are improved. At this time, the pulling direction is preferably a substantially horizontal direction from the viewpoint of operability.
Further, the fixing conveyance unit 5 is preferably provided with a capturing member for capturing unfixed toner or recording material vertically below the fixing device 4, so that unfixed due to a jam or the like below the fixing device 4. Even if the toner or the recording material falls, it can be captured so as not to fall to the image forming engine 2 side. By providing the capturing member in the fixing and conveying unit 5, cleaning processing for unfixed toner and jammed recording material can be simplified.
In addition, if the fixing conveyance unit 5 includes a member that can be detached from above after being pulled out from the apparatus main body 1, maintenance performance around the fixing apparatus 4 can be further improved.

  Furthermore, if the fixing conveyance unit 5 is configured to release the nip of the nip conveyance members before and after the fixing device 4 before being pulled out from the apparatus main body 1 or in parallel, the jam handling property of the recording material is further improved. It is preferable because it improves. At this time, it is preferable that the nip release is performed by a lever operation. In this case, the nip release can be performed by a simple operation. The nip can be released by a method such as releasing the restriction of the spring by a lever, for example.

Moreover, the following is mentioned as a 2nd aspect of the image forming apparatus which concerns on this invention.
That is, according to the present invention, as shown in FIGS. 1A and 1B, an image forming engine 2 that forms a toner image and transfers the toner image to a recording material at a transfer portion, and an upper portion of the image forming engine 2. The image forming engine 2 and the recording medium 2 are provided after the recording material supplied from the recording material supply unit 3a passes through a transfer portion with the image forming engine 2. A recording material conveyance system 3 that discharges and stores the recording material in the recording material discharge unit 3c through a conveyance path 3b that crosses between the recording material supply unit 3a and a part of the conveyance path 3b of the recording material conveyance system 3 is disposed. The fixing device 4 that fixes the toner image transferred to the recording material at the transfer portion of the image forming engine 2 and the transport path 3b of the recording material transport system 3 in the downstream transport path 3b of the fixing device 4 A forward / reverse nip transport member for transporting the recording material in a nip direction so that the forward / reverse rotation is possible; All or a part of the nip conveying member that nip conveys the recording material in the reverse conveying path 3d for returning the recording material from the forward / reverse nip conveying member position to the upstream side of the transfer site is provided on a common frame, And a reversing conveyance unit 6 which moves so as to be able to be pulled out from the main body 1.

  As described above, by enabling the reverse conveyance unit 6 including the forward / reverse nip conveyance member in the reverse conveyance path 3d to be pulled out from the apparatus main body 1, it is possible to improve the jam handling property and the maintainability in the reverse conveyance path 3d. it can. Although it is preferable to pull out all the nip conveying members, for example, when the nip is released before pulling out, it is possible to pull out a part. Note that a plurality of forward / reverse nip transport members may be provided in the reverse transport path 3d.

Furthermore, the following is mentioned as a 3rd aspect of the image forming apparatus which concerns on this invention.
That is, according to the present invention, as shown in FIGS. 1A and 1B, an image forming engine 2 that forms a toner image and transfers the toner image to a recording material at a transfer portion, and an upper portion of the image forming engine 2. The image forming engine 2 and the recording medium 2 are provided after the recording material supplied from the recording material supply unit 3a passes through a transfer portion with the image forming engine 2. A recording material conveyance system 3 that discharges and stores the recording material in the recording material discharge unit 3c through a conveyance path 3b that crosses between the recording material supply unit 3a and a part of the conveyance path 3b of the recording material conveyance system 3 is disposed. The fixing device 4 that fixes the toner image transferred to the recording material at the transfer portion of the image forming engine 2 and all or one of the nip conveying members that nip and convey the recording material at least before and after the fixing device 4. And the fixing device 4 are provided on a common base, Among the fixing conveyance unit 5 that moves so as to be able to be pulled out from the mounting body 1 and the conveyance path 3 b of the recording material conveyance system 3, the recording material is nip-conveyed in the downstream conveyance path 3 b of the fixing device 4 so as to be able to rotate forward and backward. The reverse nip conveyance member and all or a part of the nip conveyance member that nip conveys the recording material in the reverse conveyance path 3d for returning the recording material from the position of the forward / reverse nip conveyance member to the upstream side of the transfer portion are common. It is provided with the reverse conveyance unit 6 provided on a mount and moving so that it can be pulled out from the apparatus main body 1.

As described above, the fixing conveyance unit 5 and the reverse conveyance unit 6 move so as to be able to be pulled out from the apparatus main body 1, thereby increasing the visibility at the time of jam processing and maintenance around the fixing device 4 or the reverse conveyance path 3d. This can improve the jam handling performance and maintenance performance of the recording material.
At this time, if the fixing conveyance unit 5 and the reverse conveyance unit 6 are moved in conjunction with each other when being pulled out from the apparatus main body 1, the operability at the time of pulling out is improved. Note that “interlocking” does not necessarily mean that both units (the fixing conveyance unit 5 and the reverse conveyance unit 6) are pulled out integrally, but means that there may be some time lag. .

In the second aspect and the third aspect described above, it is preferable that the recording material supply unit 3a is interlocked with the reversing conveyance unit 6 so that it can be pulled out from the apparatus main body 1. In this way, the recording material The supply unit 3a and the reverse conveyance unit 6 can be arranged closer to each other, and further downsizing can be promoted.
In addition, a forward / reverse nip transport member that is provided upstream of the reverse transport path 3d and that allows the recording material after passing through the fixing device 4 to rotate to the reverse transport path 3d, and a forward / reverse nip transport member, is provided close to the recording material discharge section 3c. The conveying interval between the recording material and the discharge member for discharging the recording material to the recording material discharge portion 3c is preferably equal to or longer than the maximum length of the recording material to be conveyed. In this way, the recording material is reversed and conveyed to the reverse conveyance path 3d. The recording material does not reach the recording material discharge portion 3c, and jamming caused by a user erroneously gripping when the recording material being reversely conveyed comes out of the recording material discharge portion 3c can be prevented.
Furthermore, if this conveyance interval is set to 210 mm or more, it is possible to effectively cope with the A4 size horizontal thread often used in the market.

  In the present invention, the image forming unit including at least the image forming engine 2 moves in a direction away from the fixing device 4 before or after the fixing conveyance unit 5 is pulled out from the apparatus main body 1. A larger space around the fixing device 4 can be secured, and the jam handling performance, maintenance performance, and the like can be further improved.

The basic configuration of the present invention has the following basic effects.
1. Since the recording material conveyance system and the fixing device are arranged above the image forming engine, the installation space of the image forming apparatus can be made to depend on the installation space of the image forming engine, and the size of the image forming apparatus can be reduced accordingly. It can be easily realized.
2. Since the recording material supply unit and the recording material storage unit of the recording material conveyance system can be arranged above the image forming engine, the recording material supply operation to the recording material supply unit and the recording material storage unit on the upper side of the image forming apparatus The recording material can be taken out from the recording material, and the handling operability (replenishment operability, taking out operability) of the recording material can be improved accordingly.
3. Since the fixing device is disposed closer to the center of the image forming apparatus, the influence of outside air during fixing can be reduced and the heat of the fixing device can be reduced compared to the aspect in which the fixing device is disposed closer to the housing side wall of the image forming apparatus. It can be used effectively without escaping, and energy saving can be achieved accordingly.
4). Since the fixing device is disposed above the image forming engine, the influence of the heat of the fixing device on the image forming engine can be reduced, the image forming performance can be stabilized, and the image quality can be improved.
In other words, according to the present invention, it is possible to provide an image forming apparatus that ensures downsizing, recording material handling, energy saving, and image forming performance.

  In particular, in the present invention, all or a part of each nip conveying member for nip-conveying the recording material before and after the fixing device and the fixing device are provided on a common base, and move so that they can be pulled out from the apparatus main body. Since the fixing / conveying unit is provided, even when a jam or the like of the recording material occurs in the vicinity of the fixing device, it is possible to secure a sufficient space for the processing, and it is possible to improve the jam handling property and the maintenance property.

  Also, a forward / reverse nip transport member capable of forward / reverse rotation in the reverse transport path for an aspect having a reverse transport path for returning and transporting the recording material from the downstream side of the fixing device to the upstream side of the transfer portion of the image forming engine. And a nip conveyance member located on the downstream side of the forward / reverse nip conveyance member are all or partly provided on a common base, and are equipped with a reversal conveyance unit that can be pulled out from the apparatus main body. Even if a jam or the like of the recording material occurs around the path, a sufficient space can be secured and processed, and the jam handling performance, maintenance performance, and the like can be improved.

  Further, in contrast to the aspect having the reverse conveyance path for returning and conveying the recording material from the downstream side of the fixing device to the upstream side of the transfer portion of the image forming engine, the fixing device includes the fixing conveyance unit and the reverse conveyance unit described above. Even when a jam or the like of the recording material occurs around the reverse conveyance path, a sufficient space can be secured and processed, and the jam handling performance, maintenance performance, and the like can be improved.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 2 is a schematic diagram showing the first embodiment of the image forming apparatus to which the present invention is applied.
In the figure, the image forming apparatus 10 is provided with a one-stage paper tray 51 for supplying paper as a recording material above the apparatus, and two-stage paper trays 52 and 53 below the apparatus. An image forming engine 20 for forming an image is provided. Further, a fixing device 40 for fixing the unfixed toner image transferred onto the paper by the image forming engine 20 is disposed between the paper tray 51 and the image forming engine 20 above the apparatus.
In addition, the image forming apparatus 10 according to the present embodiment is provided with a discharge tray 55 that discharges and stores the paper on which image formation has been completed at the top of the paper tray 51, and conveys the paper from the paper trays 51 to 53 to the discharge tray 55. Various paper transport paths are also provided.

The image forming engine 20 according to the present embodiment includes four image forming units 21 (for example, yellow, magenta, cyan, and black) that form four color component toner images by electrophotography. 21a to 21d) and an intermediate transfer belt 30 on which the color component toner images formed by the image forming units 21a to 21d are sequentially transferred (primary transfer) and held.
Each of the image forming units 21 a to 21 d has a photosensitive drum 22, and around each photosensitive drum 22, a charging device 23 such as a charging roll for charging the photosensitive drum 22, and a charged photosensitive drum 22. An exposure device 24 such as a laser scanner for writing an electrostatic latent image thereon, a developing device 25 for developing the electrostatic latent image written on the photosensitive drum 22 with each color component toner, and a toner image on the photosensitive drum 22 A primary transfer roll 26 to be transferred onto the intermediate transfer belt 30 and a drum cleaner 27 to remove residual toner on the photosensitive drum 22 are provided. Reference numeral 28 (28a to 28d) denotes a toner replenishing device for replenishing each color toner to the developing device 25, and toner is replenished from the replenishing port 29 to the developing devices 25 of the respective colors via a transport pipe (not shown). It has come to be.

The intermediate transfer belt 30 is composed of, for example, an endless belt in which conductive carbon black is kneaded with polyimide resin and has a volume resistivity of about 10 ⁹ to 10 ¹² Ω · cm. For example, the tension roll 32 is used as a drive roll, and the tension roll 33 is used as a tension roll, and moves in the direction of the arrow in the figure. Reference numeral 34 denotes a belt cleaner that cleans residual toner and the like on the intermediate transfer belt 30.
In the present exemplary embodiment, the tension roll 32 is disposed obliquely below the tension roll 31, so that the intermediate transfer belt 30 can be disposed in an oblique direction, contributing to downsizing of the image forming apparatus 10. Yes.
Further, the image forming units 21a to 21d are disposed below the intermediate transfer belt 30 (positions facing the intermediate transfer belt 30 between the stretching roll 32 and the stretching roll 33), thereby the image forming unit 21 ( 21a to 21d), for example, image quality deterioration due to in-machine contamination due to toner floating or the like from the developing device 25 is prevented, and image formation with more stable image quality is enabled.

  Furthermore, in the present embodiment, the toner image transferred by the image forming unit 21 (21 a to 21 d) on the intermediate transfer belt 30 to the position facing the stretching roll 31 of the intermediate transfer belt 30 is the paper tray 51. A secondary transfer roll 35 that performs batch transfer onto the paper supplied from .about.53 is provided, and a secondary transfer site is formed using the stretching roll 31 as a backup roll. A secondary transfer bias (not shown) for transferring the toner image on the intermediate transfer belt 30 to the sheet is applied between the secondary transfer roll 35 and the stretching roll 31 of the backup roll. It has become.

  The fixing device 40 according to the present embodiment is provided in a substantially horizontal direction with the secondary transfer portion on the downstream side of the secondary transfer portion, and includes an upper fixing unit 40a and a lower fixing unit 40b as shown in FIG. ing. The upper fixing unit 40a includes a pressure roll 41 and a heat insulating cover 44 provided so as to cover the pressure roll 41, and the lower fixing unit 40b includes a heating roll 42 in which a heater 43 is disposed, and the heating roll. The heat insulating cover 45 is provided so as to cover 42. The heat shield covers 44 and 45 are each provided with a metal heat radiation plate 46 on the side of the pressure roll 41 and the heating roll 42, the outside is covered with a vacuum heat insulating material 47, and the exterior is further covered with a plastic exterior cover 48. The covered structure is adopted.

Here, as the heat radiation plate 46, for example, a mirror-finished metal such as aluminum is used, and by making the surface a radiation rate of 0.5 or less, the reflectance on the surface is increased. Moreover, the vacuum heat insulating material 47 is comprised with what provided the member whose heat conductivity is 0.03 W / (m * K) or less thickness 3mm or more, for example. Furthermore, the exterior cover 48 is made of a plastic having a low thermal conductivity.
Further, in the present embodiment, the pressure roll 41 and the heating roll 42 and the respective heat shield covers 44 and 45 are arranged with a distance of, for example, 3 to 20 mm, and the heat shield covers 44 and 45 are the pressure rolls. 41 and the heating roll 42 are sandwiched from above and below. Therefore, the heat from the heating roll 42 does not leak excessively outside the fixing device 40. Further, in the present embodiment, a conveying device 49 similar to the upstream conveying device 37 is provided on the downstream side of the fixing device 40 so as to convey the paper after being fixed by the fixing device 40. Yes.
In the fixing device 40 according to the present embodiment, the pressure roll 41 and the heating roll 42 are opposed to each other in the vertical direction, so that the sheet moves in a substantially horizontal direction in a nip region formed by both of them. It has become.

Further, in the present embodiment, as shown in FIG. 2, the toner image on the intermediate transfer belt 30 is transferred to the lower surface side (vertically below) of the sheet at the secondary transfer site. A fixing device 40 is provided between the fixing device 40 and the fixing device 40 to hold and convey the sheet upward. As the conveying device 37, an electrostatic adsorption method, an air suction method, or the like can be used, and image quality deterioration of an unfixed toner image transferred onto a sheet by the secondary transfer roll 35 is prevented.
Further, a catch pan 50 is provided below the fixing device 40 from the upstream side conveying device 37 to the downstream side conveying device 49 for catching unfixed toner and paper falling around the fixing device 40. When the paper is jammed around the fixing device 40, unfixed toner on the paper or the paper itself falls to the image forming engine 20 side so as not to have an adverse effect.

Next, the paper transport system in the present embodiment will be described with reference to FIG.
Each of the paper trays 51 to 53 is pulled out from the front side of the image forming apparatus 10 and replenishes the paper. In particular, when the upper paper tray 51 is used, it can be performed in an easy posture. It has become.
Each of the paper trays 51 to 53 is provided with a separating mechanism 56 for feeding the paper one by one. The paper fed from the paper trays 51 to 53 by the pickup roll 56a is fed with a feed roll 56b and a retard roll 56c. As a result, only the uppermost sheet is fed out.

Further, as a conveyance path through which the sheet fed from the sheet trays 51 to 53 is conveyed, a first conveyance path 61 extending downward from the sheet tray 51, a second conveyance path 62 extending upward from the sheet trays 52 and 53, and the illustrated figure. A third transport path 63 that enables paper supply from an external manual feed tray or the like is provided, and these transport paths 61 to 63 are provided on a registration roll 71 that aligns paper on the upstream side of the secondary transfer roll 35. Led.
A main transport path 64 extending in the substantially horizontal direction from the registration roll 71 through the secondary transfer roll 35 and the fixing device 40 is provided. The main conveyance path 64 changes its direction upward with a conveyance roll 72 provided on the downstream side of the fixing device 40, and discharges the sheet to the discharge tray 55 via the conveyance rolls 73 and 74. It extends to the discharge roll 75. Reference numeral 76 denotes another discharge roll for conveying the sheet to a post-processing device (not shown), for example.

Furthermore, in the present embodiment, the transport roll 73 is a forward / reverse rotating roll that performs forward / reverse driving to reversely transport the paper, and this transport roll 73 (hereinafter referred to as the forward / reverse rotating roll 73) is the starting point. A reverse conveyance path 65 for reversely conveying the sheet to the registration roll 71 from the middle of the main conveyance path 64 is provided. The forward / reverse rotation roll 73 is driven forward / reversely at a predetermined timing, so that the paper transported through the main transport path 64 is transported to the reverse transport path 65. At this time, in this embodiment, since the sheet to be discharged (in this case, the sheet to be reversed) is nipped, the nip of the conveyance roll 74 is released during the reversal conveyance. However, the present invention is not limited to this. For example, the transport roll 74 may be driven in the forward and reverse directions. In this case, the transport roll 74 may be handled integrally with the forward / reverse rotation roll 73.
Then, the sheet reversely conveyed to the reverse conveyance path 65 by the forward / reverse rotation roll 73 is returned to the registration roll 71 side through a plurality of conveyance rolls 77, and the previous toner image is transferred at the secondary transfer portion. A new toner image is formed on the paper surface opposite to the paper surface.

  Further, in the present embodiment, since the distance from the forward / reverse rotating roll 73 to the discharge roll 75 is longer than 210 mm, even if the A4 size is frequently used as a sheet, For example, a sheet that is reversed and conveyed for duplex printing does not face the discharge tray 55 (the leading end of the sheet hits the discharge tray 55). There is no such thing.

In particular, as shown in FIGS. 4 and 5 (particularly, as shown in the broken line in FIG. 4), the peripheral members including the fixing device 40 are not shown in the image forming apparatus 10 in the present embodiment. The fixing conveyance unit 100 mounted on the conveyance stand can be pulled out from the apparatus main body (the casing of the image forming apparatus 10).
The fixing conveyance unit 100 according to the present exemplary embodiment includes a fixing device 40, a conveyance device 37 and a secondary transfer roll 35 located upstream of the fixing device 40, a conveyance device 49 and a conveyance roll 72 located downstream, The catch pan 50 is provided below the fixing device 40.

Further, when the fixing conveyance unit 100 is pulled out of the apparatus main body by a lever operation not shown, as shown in FIG. 6, the secondary transfer roll 35 and the conveyance roll 72 (upper conveyance roll 72a and lower conveyance roll 72b). And the conveyance device 37 are also lifted upward so that it is easy to see a paper jam or the like in the fixing conveyance unit 100 when it is pulled out from the apparatus main body.
FIG. 7 shows an example of a release mechanism for releasing the nip of the transport roll 72 (configured by the upper transport roll 72a and the lower transport roll 72b) by the lever operation described above. In the state of being housed in the image forming apparatus 10, an upward biasing force is applied to the shaft 721a of the upper transport roll 72a by the spring 120. At this time, the notch portion 110a of the slide member 110 is moved to the upper transport roll 72a. By pressing the, the influence of the urging force is eliminated, and the nip of the transport roll 72 can be held. Then, when the slide member 110 is slid in the direction of the arrow A in the figure by a lever operation not shown, the shaft 721a of the upper transport roll 72a moves gradually from the notch portion 110a of the slide member 110 to the inclined portion 110b. Thus, the upward urging force of the spring 120 acts on the upper conveying roll 72a. Therefore, the nip of the transport roll 72 is released. FIG. 7 shows an example of the nip release of the transport roll 72, but in the present embodiment, the nip release of the secondary transfer roll 35 is performed by the same method. Also, the transport device 37 has a similar configuration, and is lifted upward when the fixing transport unit 100 is pulled out from the apparatus main body.

Next, a basic image forming process of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.
Now, when image data of each color component image (yellow, magenta, cyan, black) is sent to the exposure device 24 of each image forming unit 21 (21a to 21d), it is transferred onto the photosensitive drum 22 of each image forming unit 21. An electrostatic latent image for each color component is formed, and the electrostatic latent image is visualized by the developing device 25 containing the corresponding color toner, and each color toner image is formed on the photosensitive drum 22. The
The color toner images on the photosensitive drums 22 are sequentially primary-transferred onto the intermediate transfer belt 30 by the primary transfer roll 26 at the primary transfer site where the photosensitive drums 22 and the intermediate transfer belt 30 are in contact with each other, and are overlaid. The

The unfixed toner image primarily transferred onto the intermediate transfer belt 30 in this way is moved to the secondary transfer position (configured by the secondary transfer roll 35 and the stretching roll 31) as the intermediate transfer belt 30 moves. Move to.
Here, assuming that a sheet is supplied from the sheet tray 51, the following sheet conveyance will be described.
Only one sheet fed from the sheet tray 51 by the separation mechanism 56 is conveyed to the first conveyance path 61. The sheet conveyed through the first conveyance path 61 is aligned by the registration roll 71 and then conveyed to the secondary transfer portion at a predetermined timing, and the unfixed toner image on the intermediate transfer belt 30 by the secondary transfer roll 35. Are collectively transferred (secondary transfer) onto the paper.
The sheet on which the unfixed toner images are collectively transferred is sucked and conveyed by the conveying device 37 and reaches the fixing device 40, where the unfixed toner image is fixed.
The sheet that has passed through the fixing device 40 is conveyed to the discharge roll 75 via the conveyance roll 72, the forward / reverse rotation roll 73, and the conveyance roll 74, and discharged to the discharge tray 55 in a face-up state (toner image is upward). Is done.

For example, when the paper jams around the fixing device 40 on the main conveyance path 64,
By operating the lever, the slide member 110 (see FIG. 7) is slid, and the fixing conveyance unit 100 is pulled out from the apparatus main body while releasing the nip of the conveyance roll 72 and the like. At this time, as shown in FIG. 6, the pulled-out fixing conveyance unit 100 has the secondary transfer roll 35, the conveyance device 37, and the upper conveyance roll 72a lifted, so that it is easy to check the jammed paper, and the fixing device 40 When the jam occurs in the nip area, it can be easily removed by turning the pressure roll 41 (see FIG. 3) of the fixing device 40, for example.
Further, in the present embodiment, even if unfixed toner remains on the sheet upstream of the nip region of the fixing device 40 by the catch pan 50 below the fixing device 40, the unfixed toner is dropped. Since it can be captured by the catch pan 50 and the fall of the paper piece or the like can be caught, the unfixed toner or the paper piece may fall and adversely affect the image forming engine 20 (see FIG. 2). There is nothing.

  Furthermore, in this embodiment, after the fixing conveyance unit 100 is pulled out from the apparatus main body, the secondary transfer roll 35, the conveyance device 37, and the conveyance roll 72 of the fixing conveyance unit 100 can be replaced from above. Also, maintainability for parts replacement, cleaning, etc. is greatly improved. Further, by removing the catch pan 50 from the fixing conveyance unit 100 and cleaning it, the catch pan 50 can be easily cleaned even if unfixed toner or the like is accumulated on the catch pan 50.

As described above, in the present exemplary embodiment, when a paper jam or the like occurs despite the fact that the fixing device 40 is disposed near the center of the image forming apparatus 10, the fixing conveyance unit 100 is pulled out, thereby Visibility is improved and jam can be easily removed. Further, it can be easily performed when maintenance or the like is required. Further, the catch pan 50 can prevent the unfixed toner from adversely affecting the image, and can prevent internal contamination and floor contamination.
Since the paper tray 51 is provided on the upper part of the image forming apparatus 10, a “person-friendly” configuration is possible without taking an unreasonable posture when paper is replenished.
Further, since the fixing device 40, the intermediate transfer belt 30, and the image forming unit 21 are arranged in this order from the top, stable image formation is possible without being affected by heat from the fixing device, and the toner replenishing device 28. Also, it can be installed below the fixing device 40, and the influence of heat of the fixing device 40 can be prevented even during long-term use, and adverse effects on image quality and thermal deterioration of toner can be suppressed.
Further, since the intermediate transfer belt 30 is disposed obliquely, the image forming unit 21 is provided below, and the distance from the image forming unit 21 to the secondary transfer position is shortened, a compact, high-speed and high-quality image forming apparatus can be obtained. It becomes possible to provide.

In the present embodiment, the nip release of the secondary transfer roll 35 is performed in the same manner as the nip release of the transport roll 72, so that one end (front side) of the secondary transfer roll 35 in the axial direction can be easily operated by lever operation. Although the mode of lifting is shown, the present invention is not limited to this, and the nip release of the secondary transfer roll 35 may be performed as shown in FIG.
FIG. 8 is a conceptual diagram of the image forming apparatus 10 (corresponding to FIG. 2) of the present embodiment. The image forming engine 20 is provided below the paper tray 51, and the fixing device 40 is provided therebetween. It has become. The secondary transfer roll 35 located upstream of the fixing device 40 is different from the above-described first embodiment in the nip releasing direction, and is substantially parallel moved in the direction of arrow B in the figure to release the nip. ing.

In this nip releasing method, for example, the slide members 110 shown in FIG. 7 may be provided at both ends (on the shaft) of the secondary transfer roll 35, and the slide members 110 may be simultaneously slid by lever operation. There may be a configuration in which a motor and a cam are used and electrically moved.
Thus, if the secondary transfer roll 35 is moved in parallel, the axial pressure change of the secondary transfer roll 35 when the nip is released can be kept constant, and the axial nip of the secondary transfer roll 35 can be maintained. The pressure can be stably maintained over a long period of time. In addition to the secondary transfer roll 35, the transport roll 72 may have the same configuration.

In this embodiment, the fixing conveyance unit 100 (see FIG. 4) is pulled out from the apparatus main body. However, for example, as the fixing conveyance unit 100 moves, the image forming engine 20 moves away from the fixing conveyance unit 100 side. It may be.
FIG. 9 is a conceptual diagram of the image forming apparatus 10 (corresponding to FIG. 2) of the present embodiment. The image forming engine 20 rotates in the direction of arrow D in the figure with the rotation support shaft C as a fulcrum. The intermediate transfer belt 30 is separated from the secondary transfer roll 35. In this way, it is possible to release the nip of the secondary transfer roll 35 at the secondary transfer site, and further, a space is secured below the fixing conveyance unit 100 (see FIG. 4). Maintenance can be further improved.
The timing for rotating the image forming engine 20 is not particularly limited, and may be before the fixing conveyance unit 100 is pulled out from the apparatus main body, or may be performed in parallel. In such a case, it may be a mode in which the fixing conveyance unit 100 is independently rotated.

Embodiment 2
FIG. 10 shows a main part of the second embodiment of the image forming apparatus to which the present invention is applied.
The image forming apparatus in the present embodiment is configured in substantially the same manner as in the first embodiment, but the units pulled out from the apparatus main body during jam processing or the like are different, and the four units shown in FIG. The difference from Embodiment 1 is that it is configured to be drawable. Note that the basic configuration of the image forming apparatus 10 is the same as that of the first embodiment, and a description thereof will be omitted.

In the present embodiment, the unit pulled out from the apparatus main body is composed of a fixing conveyance unit 100 similar to that of the first embodiment, a forward / reverse rotation roll 73 provided in the reverse conveyance path of paper, and a plurality of conveyance rolls 77. The reversing conveyance unit 200, the paper tray 51, the paper feed mechanism 56, and the conveyance roll 78 are the paper feed unit 300, and the discharge unit 400 is composed of the conveyance roll 74 and the discharge rolls 75 and 76.
In the present embodiment, these four units are positioned by a slide rail (not shown) provided below or on the side of each unit on a transport stand (not shown). It is comprised so that it may be pulled out to the front side. Further, in the present embodiment, when the reverse conveyance unit 200 is pulled out, the nip of the conveyance roll 74 on the discharge unit 400 side is released, so that there is no particular problem when the reverse conveyance unit 200 is pulled out. It has become. In the present embodiment, the fixing conveyance unit 100 is pulled out simultaneously when the reverse conveyance unit 200 is pulled out, and only the fixing conveyance unit 100 is pulled out when the fixing conveyance unit 100 is pulled out.

FIG. 11 shows a state where the fixing conveyance unit 100 and the reverse conveyance unit 200 are integrally pulled out from the apparatus main body when a paper jam occurs, and a paper feeding unit 300 (not shown). The discharge unit 400 remains held in the apparatus main body. In the figure, a part of the transport roll 77 of the reverse transport unit 200 is omitted.
Thus, by pulling out the fixing conveyance unit 100 and the reverse conveyance unit 200 from the apparatus main body, the paper jam removal performance in the reverse conveyance path (formed by the reverse conveyance unit 200) is improved. Further, it is possible to cope with a paper jam between the conveyance roll 72 on the fixing conveyance unit 100 side and the forward / reverse rotation roll 73 on the reverse conveyance unit 200 side, and an image forming apparatus excellent in jam handling and maintenance is provided. be able to.

Further, in the present embodiment, after the fixing and conveying unit 100 and the reverse conveying unit 200 are pulled out, the reverse conveying unit 200 is lifted as shown in FIG. By lifting the front side in the direction of the arrow), a wide space above the fixing conveyance unit 100 can be secured, and the jam handling performance and maintenance performance of the fixing conveyance unit 100 can be improved. At this time, the reverse conveyance unit 200 is configured to be easily lifted by a hinge and a spring provided on the back side (the direction opposite to the direction pulled out from the apparatus main body), for example, so that a simple operation is possible. It becomes.
In the present embodiment, the fixing conveyance unit 100 and the reverse conveyance unit 200 are mainly drawn out from the apparatus main body. However, the present invention is not limited to this. For example, each unit is configured to be drawn out alone. Needless to say, it may be.
Further, if the reverse conveyance unit 200 and the discharge unit 400 are pulled out integrally, it is possible to deal with a jam in the vicinity of the forward / reverse rotation roll 73 of the reverse conveyance unit 200 without releasing the nip of the conveyance roll 74. And the configuration is simplified. Further, if this is done, it is possible to cope with even a mode in which the transport roll 74 performs forward / reverse driving.

Embodiment 3
FIG. 13 shows an essential part of Embodiment 3 of the image forming apparatus to which the present invention is applied. In the present embodiment, among the units of the second embodiment (see FIG. 10), the reverse conveyance unit 200, the paper feed unit 300, and the discharge unit 400 are integrally drawn from the apparatus main body. Note that the basic configuration of the image forming apparatus 10 is the same as that of the first embodiment, and a description thereof will be omitted.
In the present embodiment, the jammed paper can be easily removed when a paper jam occurs in the reverse conveyance unit 200, the paper feed unit 300, and the discharge unit 400.

  Further, as shown in FIG. 14, after the reverse conveyance unit 200, the paper feeding unit 300, and the discharge unit 400 are pulled out, the reverse conveyance unit 200 is lowered in the direction (downward) opposite to the direction shown in the second embodiment. By doing so, it becomes easier to visually check the state of the reverse conveyance unit 200 with the paper tray 51 left in the paper supply unit 300 as it is, and the jam handling property and the maintenance property can be further improved.

(A) and (b) are explanatory views showing the configuration of the image forming apparatus according to the present invention, in which (a) shows a normal state, and (b) shows a state in which a unit is pulled out for jam processing or the like. 1 is an explanatory diagram showing Embodiment 1 of an image forming apparatus to which the present invention is applied. FIG. 2 is an explanatory diagram illustrating a fixing device according to a first embodiment. 3 is an explanatory diagram illustrating a fixing conveyance unit according to Embodiment 1. FIG. FIG. 4 is an explanatory diagram illustrating a state where the fixing conveyance unit according to the first embodiment is pulled out from the apparatus main body. FIG. 4 is an explanatory diagram illustrating nip release of the fixing conveyance unit according to the first embodiment. FIG. 3 is an explanatory diagram illustrating a nip holding mechanism according to the first embodiment. FIG. 6 is an explanatory view showing a nip releasing mechanism of a secondary transfer roll as a modified example of the first embodiment. FIG. 6 is an explanatory diagram showing a mechanism for rotating an image forming engine as a modification of the first embodiment. FIG. 6 is an explanatory view showing a drawer unit according to Embodiment 2. FIG. 10 is an explanatory diagram showing a state in which a unit is pulled out in the second embodiment. It is explanatory drawing which shows the state which the roll lifted after the unit was pulled out in Embodiment 2. FIG. 11 is an explanatory diagram showing a unit that is drawn out according to a third embodiment. It is explanatory drawing which shows the state which the roll fell below after having been pulled out in Embodiment 3. It is explanatory drawing which shows an example of the conventional image forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Apparatus main body, 2 ... Image forming engine, 3 ... Recording material conveyance system, 3a ... Recording material supply part, 3b ... Conveyance path, 3c ... Recording material discharge | emission part, 3d ... Reverse conveyance path, 4 ... Fixing device, 5 ... Fixing conveyance unit, 6 ... Reverse conveyance unit

Claims (14)

An image forming engine for forming a toner image and transferring the toner image to a recording material at a transfer site;
An image forming engine having a recording material supply unit in which a recording material can be supplied above the image forming engine, and after the recording material supplied from the recording material supplying unit has passed through a transfer portion with the image forming engine And a recording material transport system for discharging and storing the recording material in the recording material discharge section through a transport path that crosses between the recording material supply section and the recording material supply section,
A fixing device that is disposed in a part of the conveyance path of the recording material conveyance system and fixes the toner image transferred to the recording material at a transfer portion of the image forming engine;
At least all or a part of each nip conveying member for nip-conveying the recording material before and after the fixing device and the fixing device are provided on a common frame, and include a fixing conveyance unit that can be pulled out from the apparatus main body. An image forming apparatus. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the fixing conveyance unit includes a capturing member that captures unfixed toner or a recording material vertically below the fixing device. The image forming apparatus according to claim 1 or 2,
The image forming apparatus, wherein the fixing conveyance unit includes a member that can be detached from above after being pulled out. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the fixing conveyance unit is configured to release a nip of a nip conveyance member before and after the fixing apparatus before or along with the fixing conveyance unit. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the fixing conveyance unit is configured to release a nip of a nip conveyance member before and after the fixing device by a lever operation. An image forming engine for forming a toner image and transferring the toner image to a recording material at a transfer site;
An image forming engine having a recording material supply unit in which a recording material can be supplied above the image forming engine, and after the recording material supplied from the recording material supplying unit has passed through a transfer portion with the image forming engine And a recording material transport system for discharging and storing the recording material in the recording material discharge section through a transport path that crosses between the recording material supply section and the recording material supply section,
A fixing device that is disposed in a part of the conveyance path of the recording material conveyance system and fixes the toner image transferred to the recording material at a transfer portion of the image forming engine;
A forward / reverse nip transport member that nips the recording material in a transport path downstream of the fixing device among the transport paths of the recording material transport system, and upstream of the transfer portion from the forward / reverse nip transport member position. A reversal conveyance unit that is provided on a common base and all or a part of a nip conveyance member that nip conveys the recording material in a reversal conveyance path for returning the recording material to the side, and moves so as to be able to be pulled out from the apparatus main body. An image forming apparatus. An image forming engine for forming a toner image and transferring the toner image to a recording material at a transfer site;
An image forming engine having a recording material supply unit in which a recording material can be supplied above the image forming engine, and after the recording material supplied from the recording material supplying unit has passed through a transfer portion with the image forming engine And a recording material transport system for discharging and storing the recording material in the recording material discharge section through a transport path that crosses between the recording material supply section and the recording material supply section,
A fixing device that is disposed in a part of the conveyance path of the recording material conveyance system and fixes the toner image transferred to the recording material at a transfer portion of the image forming engine;
All or a part of each nip conveying member that nip conveys the recording material before and after the fixing device and the fixing device are provided on a common base, and a fixing conveying unit that moves so as to be drawable from the apparatus main body;
A forward / reverse nip transport member that nips the recording material in a transport path downstream of the fixing device among the transport paths of the recording material transport system, and upstream of the transfer portion from the forward / reverse nip transport member position. A reversal conveyance unit that is provided on a common base and all or a part of a nip conveyance member that nip conveys the recording material in a reversal conveyance path for returning the recording material to the side, and moves so as to be able to be pulled out from the apparatus main body. An image forming apparatus. The image forming apparatus according to claim 7.
An image forming apparatus, wherein the fixing conveyance unit and the reverse conveyance unit move in conjunction with each other. The image forming apparatus according to claim 6 or 7,
An image forming apparatus, wherein the reversing conveyance unit enables the recording material supply unit to be pulled out from the apparatus main body when being pulled out from the apparatus main body. The image forming apparatus according to claim 6 or 7,
A forward / reverse nip transport member that is provided upstream of the reverse transport path and guides the recording material after passing through the fixing device to the reverse transport path, and a recording material discharge section that is provided close to the recording material discharge section. An image forming apparatus, wherein a conveyance interval with a discharge member for discharging a recording material is not less than a maximum length of the recording material to be conveyed. The image forming apparatus according to claim 10.
The image forming apparatus, wherein the conveyance interval is 210 mm or more. The image forming apparatus according to claim 1.
An image forming apparatus, wherein an image forming unit including at least an image forming engine moves in a direction away from the fixing device before or in parallel with the fixing conveyance unit being pulled out from the apparatus main body. The image forming apparatus according to claim 1,
The image forming engine includes an image forming unit that forms and supports a toner image, and an intermediate transfer member that temporarily conveys and holds the toner image from the image forming unit, and the image forming unit is located below the intermediate transfer member. An image forming apparatus that is arranged. The image forming apparatus according to claim 13.
The image forming apparatus, wherein the intermediate transfer member is a belt member.

Images