JP2001220046A - Image forming device and after-processing unit used in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize after-processing units arranged in parallel in an image forming unit. SOLUTION: An image forming device is provided with after-processing units 3 which are arranged in parallel in image forming unit 1 and performs after-processing for a recording sheet 5 which is discharged from the image forming unit 1 and on which a picture image is formed. In this after-processing unit 3, an inlet opening 7 corresponding to a discharge opening 6 on the image forming unit 1 side is provided in a lower half part on the picture image forming unit 1 side of a unit case 3a, an outlet opening 8 is provided in an upper half part on the opposite side to the image forming unit 1 of the unit case 3a, an inclined conveyance passage 9 is provided between the inlet opening 7 and the outlet opening 8, and an after-processing device 10 is arranged on the halfway of the inclined conveyance passage 9. Moreover, a sheet conveyance passage length L between a fixation section of a fixing device 2b of an image formation module 2 and an after-processing section of the after-processing device 10 is set to be longer than a length of the maximum size sheet used. Furthermore, this invention is applied to the after-processing units 3 themselves which are used in the image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus in which a post-processing unit is arranged in parallel with an image forming unit and a post-processing unit used in the image forming apparatus. Regarding improvement.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine or a printer, a discharge section of a recording sheet on which an image has been formed is provided to an image forming unit from the viewpoint of maintaining good operability of recording sheet handling. It is common practice to set a position and height that are easy for the user to handle.
For this reason, in a mode in which a post-processing unit is arranged in parallel as an external device in this type of image forming unit, the post-processing unit is connected to the discharging unit of the image forming unit, and the recording sheet discharging unit of the post-processing unit is It is necessary to set the position and height of the post-processed recording sheet so that it can be easily handled.

[0003]

In such an embodiment, for example, as shown in Japanese Patent Application Laid-Open No. 9-30712, the sheet conveying path in the post-processing unit is disposed in a substantially horizontal direction. Since a post-processing device such as a curl straightening device (decaler) will be installed in
The dimension in the direction in which the post-processing units are arranged with respect to the image forming units (hereinafter simply referred to as the width dimension as necessary) has to be increased. In order to solve such technical problems, it is necessary to reduce the width of the post-processing unit as much as possible. However, with such a design, the space between the sheet discharge unit of the image forming unit and the post-processing device, and In addition, it is not possible to secure a sufficiently long sheet conveying path connecting the post-processing device and the sheet discharge unit of the post-processing unit, and it becomes difficult to perform a jam clearing process on the recording sheet in the conveying path.

[0004] In addition, due to demands for colorization, high speed, and long life, among image forming modules housed in the image forming unit, for example, the size of a developing unit and a transfer unit has been increased. The ratio of occupying the dimension in the height direction of the image forming apparatus is increasing. Under such circumstances, the transfer position of the image forming module to the recording sheet is moved downward, and the sheet conveyance path must be set at the lower part of the apparatus. Along with this, a sheet discharge unit from the image forming unit must also be provided at the lower part of the apparatus. However, if a sheet discharge unit is provided at the lower part of the apparatus, it becomes difficult for the user to handle the recording sheet in the first place. It is not preferable.

In this case, in order to ensure the easiness of handling of the discharged sheet, for example, a technique has been proposed in which an external discharging device is connected, a sheet conveying path is provided upward, and the recording sheet is guided upward. (For example, see JP-A-6-250)
455). However, this prior art merely guides the discharged recording sheet upward, and when post-processing is performed on the recording sheet, a post-processing unit must be further connected to the outside, The size of the entire image forming apparatus increases more and more.

Further, for example, when the post-processing device is a curl correcting device (decurling device), Japanese Patent Application Laid-Open No. 9-30712 discloses
If the curl correction device is installed immediately after the fixing device of the image forming module as in the publication, the long recording sheet will be conveyed simultaneously across the fixing device and the curl correction device, and the difference in the respective conveyance speeds There is a concern that the recording sheet may be damaged due to the pulling of the recording sheet. Further, the curl amount of the recording sheet gradually changes as the recording sheet cools after the fixing process, but immediately after passing through the fixing device, the recording sheet has a high temperature due to heat generated by the fixing process. In the state, the curl amount is not stable, and even if curl correction is performed at that point, the curl amount is unstable, so it is not possible to control the appropriate correction amount,
There was concern that it was difficult to achieve sufficient curl correction.

As described above, in the image forming apparatus of the type in which the post-processing unit is arranged in parallel with the image forming unit, the size of the post-processing unit is unnecessarily increased, or the degree of post-processing on the recording sheet is impaired. Therefore, how to optimize the post-processing units arranged in parallel with the image forming units has become an important technical problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above technical problem, and an image forming apparatus in which a post-processing unit arranged in parallel with an image forming unit is optimized, and a post-processing apparatus used in the image forming apparatus. A processing unit is provided. Here, the optimization of the present invention has two technical viewpoints, and the first technical viewpoint is to easily realize the miniaturization of the post-processing unit while maintaining good handling of the recording sheet. A second technical point of view is to always keep good the post-processing condition on the recording sheet.

[0009]

That is, one aspect of the present invention based on the first technical point of view is to form an image on a supplied recording sheet 5 as shown in FIG. An image forming unit 1 in which the module 2 is accommodated, and a post-processing unit 3 which is arranged in parallel with the image forming unit 1 and performs post-processing on the image-formed recording sheet 5 discharged from the image forming unit 1 The post-processing unit 3 is provided in the lower half of the unit case 3a on the image forming unit 1 side (less than half H / 2 of the height dimension H of the post-processing unit 3) at the discharge opening 6 on the image forming unit 1 side. A corresponding inlet opening 7 is provided and the unit case 3
a, an outlet opening 8 is provided in the upper half of the opposite side of the image forming unit 1 (a portion exceeding a half H / 2 of the height dimension H of the post-processing unit 3), and between the inlet opening 7 and the outlet opening 8; , And a post-processing device 10 is provided in the middle of the inclined conveying path 9.

In such technical means, as shown in FIG. 1, the image forming module 2 is not limited to an intermediate transfer type tandem module, but includes various modules. In particular, in the image forming module 2 that performs double-sided transfer or multiple transfer on the recording sheet 5, a sheet return transport mechanism 2a that directly or reverses the recording sheet 5 on which single-sided image formation has been performed and returns the recording sheet 5 to the transfer unit again is used. It is attached. The position of the outlet opening 8 may be appropriately selected from the ease of handling of the recording sheet 5, while the position of the inlet opening 7 is determined by the post-processing device 10.
May be appropriately selected in consideration of the size of the sheet and the required length of the inclined conveyance path 9.

Further, in this aspect, the present invention is not limited to the image forming apparatus, but also applies to the post-processing unit 3 itself used in the image forming apparatus.
In this case, the present invention is used in an image forming apparatus including an image forming unit 1 in which an image forming module 2 for forming an image on a supplied recording sheet 5 is accommodated, as shown in FIG. A post-processing unit 3 that performs post-processing on an image-formed recording sheet 5 that is arranged in parallel with the image forming unit 1 and that is discharged from the image forming unit 1; An inlet opening 7 is provided in the half, an outlet opening 8 is provided in the upper half of the unit case 3a on the side opposite to the image forming unit 1, and an inclined conveyance path 9 is provided between the inlet opening 7 and the outlet opening 8. In addition, the post-processing device 1
0 is provided.

Another aspect of the present invention based on the second technical viewpoint is that, as shown in FIG. 1, an image forming module 2 for forming an image on a supplied recording sheet 5 is accommodated therein. The image forming module 2 includes an image forming unit 1 including a fixing device 2b for fixing an image on a recording sheet 5, and an image forming unit 1 that is arranged in parallel with the image forming unit 1 and has an image formed and discharged from the image forming unit 1. A post-processing unit 3 that performs post-processing on the recording sheet 5 by the post-processing device 10, and uses the sheet conveyance path length L between the fixing portion of the fixing device 2 b and the post-processing portion of the post-processing device 10. It is characterized in that it is set longer than the size sheet length.

In this aspect, when the first technical viewpoint is taken into consideration, as shown in FIG.
In the lower half of the unit case 3a on the image forming unit 1 side (less than half H / 2 of the height H of the post-processing unit 3), an inlet opening 7 corresponding to the discharge opening 6 on the image forming unit 1 side is provided. At the same time, an outlet opening 8 is provided in the upper half of the unit case 3a on the opposite side of the image forming unit 1 (a portion exceeding half the height H of the post-processing unit 3), and the inlet opening 7 and the outlet opening are provided. 8 and a post-processing device 1 in the middle of the inclined conveying path 9.
It is preferable to arrange 0.

Further, in this embodiment, the present invention is not limited to the image forming apparatus, but also applies to the post-processing unit 3 itself used in the image forming apparatus. In this case, according to the present invention, as shown in FIG. 1, an image forming module 2 for forming an image on a supplied recording sheet 5 is accommodated, and the image on the recording sheet 5 is fixed to the image forming module 2. Is used in an image forming apparatus provided with an image forming unit 1 including a fixing device 2b, which is disposed in parallel with the image forming unit 1, and the image-formed recording sheet 5 discharged from the image forming unit 1 A post-processing unit 3 for performing post-processing by the processing device 10, wherein a sheet conveying path length L between a fixing portion of the fixing device 2b and a post-processing portion of the post-processing device 10 is set to be longer than the maximum usable sheet length. It is characterized by having done.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. Embodiment 1 FIG. 2 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
FIG. In FIG. 1, the image forming apparatus according to the present embodiment is an image forming apparatus employing a so-called tandem-type intermediate transfer system, and includes an image forming unit 21 in which an image forming module 30 is housed, and an image forming unit 2.
1, a sheet supply unit 22 that supplies a recording sheet (not shown) to the image forming unit 21 and a recording sheet that is disposed in parallel with the image forming unit 21 and on which an image is formed by the image forming unit 21. And a post-processing unit 23 for performing post-processing.

In this embodiment, the image forming unit 21 forms each color component toner image (for example, yellow (Y), magenta (M), cyan (C), black (K)) by, for example, an electrophotographic method. The photosensitive drum 31 (specifically, 31Y, 31M, 31C, 31K) for forming and carrying each color component toner image is arranged in parallel. The respective color component toner images formed on the photosensitive drum 31 are sequentially primary-transferred onto the intermediate transfer belt 40, and the respective color component toner images on the intermediate transfer belt 40 are recorded on the recording sheet supplied from the sheet supply unit 22 by the secondary transfer roll 50. Is secondary-transferred and guided to the fixing device 60.

In the present embodiment, each photosensitive drum 3
1, a uniform charger (not shown) for charging the photoconductor drum 31, a laser exposure device 33 for writing an electrostatic latent image on the photoconductor drum 31, A developing unit 34 for visualizing the electrostatic latent image on the drum 31; a primary transfer roll 35 for transferring each color component toner image on the photosensitive drum 31 to the intermediate transfer belt 40; a residual toner on the photosensitive drum 31; An electrophotographic device such as a cleaner 36 for removing the toner is sequentially arranged. The intermediate transfer belt 40 is circulated and transported by being stretched by a plurality (five in this example) of stretching rolls 41 to 45. For example, the stretching roll 41 is used as a driving roll, and other stretching rolls are used. The stretching rolls 42 to 45 are driven rollers, and any of the stretching rolls 42 to 45, for example, the stretching roll 43 is made to function as a tension roll that applies tension to the intermediate transfer belt 40. Things. In the present embodiment, a portion of the intermediate transfer belt 40 facing the tension roll 44 is set as a secondary transfer portion, and a secondary transfer roll is provided on the surface side of the secondary transfer portion of the intermediate transfer belt 40. The transfer bias is applied between the secondary transfer roll 50 and the tension roll 44 (functioning as a backup roll) facing the secondary transfer roll 50.

Further, in the present embodiment, the sheet supply unit 22 has multi-stage (three-stage in this example) sheet supply trays 71 to 73 as shown in FIG. Accommodates recording sheets made of plain paper of different sizes, while the lowermost large-capacity sheet supply tray 73 accommodates special sheets including recording sheets having high bending rigidity such as coated paper and cardboard. It was done. Particularly, in the present embodiment, the sheet supply tray 7
The sheet supply tray 73 includes feed rolls 76 on the image forming unit 21 side. Then, the sheet transport path from the sheet supply trays 71 and 72 is directed upward from the side opposite to the image forming unit 21 of the sheet supply unit 22, and is directed toward the image forming unit 21 using the upper space. , Is configured as a detour conveyance path 77 directed downward. on the other hand,
The sheet transport path from the sheet supply tray 73 is configured as a direct transport path 78 extending substantially linearly to the image forming unit 21 side, and the direct transport path 78 and the bypass transport path 77 communicate with a merge transport path 79. The recording sheet is connected to the image forming unit 21 through the outlet 80.

Further, a plurality of pairs of transport rolls 81 are provided at predetermined intervals in the bypass transport path 77, the direct transport path 78, and the merge transport path 79 of the sheet supply unit 22. In particular, the unit case 2 of the sheet supply unit 22
A cover 10 that opens and closes facing the bypass conveyance path 77 includes a part of the cover 20 that is located on the opposite side of the image forming unit 21.
0 is provided. The cover 100 is rotatable, for example, using the back side of the unit case 220 as a rotation fulcrum, and rotatably holds a driven roll 81b of the paired transport rolls 81 (81a, 81b). The drive roll 81a of the transport roll 81 when opened
And the driven roll 81b are separately arranged. Further, in the present embodiment, the image forming unit 2 is provided in the horizontal conveyance path portion of the bypass conveyance path 77 of the sheet supply unit 22.
1 and a connecting conveyance path 10 extending in the horizontal direction toward the opposite side.
1 is formed, and this connection conveyance path 101 is, for example, in a mode in which another sheet supply unit (not shown) is disposed adjacent to the sheet supply unit 22, and the recording is supplied from another sheet supply unit. The sheet feed unit 22 serves as a transport path for receiving the sheet and guiding the sheet to the bypass transport path 77, or as a recording sheet insertion unit by manual feeding of the sheet supply unit 22.

Further, in the present embodiment, an image reading unit 24 and a user operation unit 25 are disposed above the sheet supply unit 22. The image reading unit 24 optically reads an image of a document placed on a document table, and includes, for example, a light source, a reflection mirror, an imaging lens, a CCD sensor, and the like.

In this embodiment, the post-processing unit 23 is, as shown in FIGS. 2 and 3, a unit case corresponding to the recording sheet discharge port 211 opened in the unit case 210 of the image forming unit 21. 230 has an inlet opening 231, while the image forming unit 21
The outlet opening 232 is located at the unit case 230
Has been established. In this example, the entrance opening 231 is located in the lower half of the post-processing unit 23 (the height H of the post-processing unit 23).
Less than half H / 2) (for example, height 300 to 4)
On the other hand, the outlet opening 232 is provided at a predetermined position (for example, about 750 mm to 850 mm) of the upper half of the post-processing unit 23 (a part exceeding half the height H / 2 of the height H of the post-processing unit 23). ) And outlet opening 2
A sheet discharge tray 233 is attached to the unit case 230 corresponding to the T.32. Further, the entrance opening 23
1 and an outlet opening 232, there is provided an inclined conveying path 234 which is directed in an oblique direction. The inclined conveying path 234 is branched into two on the way. Curl straightening device 235,2 for curl straightening
36 are provided. In addition, an appropriate number (three in this example) of paired transport rolls 237 to 23 are provided on the inclined transport path 234.
9 are provided.

In the sheet conveying path in the image forming unit 21, the recording sheet supplied from the sheet supply unit 22 is guided to the secondary transfer portion, and then passes through the fixing unit 60 and is discharged to the post-processing unit 23. In addition to the path, a path is provided for reversing the recording sheet sent from the fixing device 60 and returning it to the secondary transfer portion again. Here, in the present embodiment, the side edge of the recording sheet is aligned with the side initial position by a plurality of (for example, three) pairs of conveying skew rollers 82 arranged upstream of the secondary transfer portion. Thereafter, the recording sheet is conveyed to the secondary transfer site in a state where the recording sheet is aligned and aligned with the reference position by a paired registration roll (registration roll) 83 disposed before the secondary transfer site,
The recording sheet after passing through the secondary transfer portion is transferred to, for example, a conveyance belt 8.
4, the sheet is conveyed to the fixing device 60.

Further, as a sheet returning mechanism used in the present embodiment, the recording sheet sent from the fixing device 60 is conveyed by an appropriate number of conveying rolls 86 along a loop-shaped return path 85. However, a reversing section (in the present example, utilizing the lower space in the post-processing unit 23) 87 is provided in the middle of the return path 85, and the recording sheet is reversed via the reversing section 87. . A part of the return path 85 utilizes the space in the sheet supply unit 22 and is connected to the merging conveyance path 79.

Next, the operation of the image forming apparatus according to this embodiment will be described. Now, assuming that a recording sheet has been sent out from either the sheet supply tray 71 or 72 of the sheet supply unit 22, this recording sheet passes through the bypass conveyance path 77 and the merge conveyance path 79 from the delivery port 80 to the image forming unit 21 side. The sheet is sent out, and is conveyed to the secondary transfer site via the skewed conveyance roller 82 and the registration roller 83. In this state, the color toner image formed by the image forming module 30 is transferred to the recording sheet, and the transferred recording sheet passes through the fixing device 60 and is conveyed to the post-processing unit 23 side. In the post-processing unit 23, the recording sheet is conveyed through the inclined conveyance path 234. In this process, for example, one of the curling devices 235 and 236 may be used under the condition that the recording sheet is curled. Is performed (curl correction), and the sheet discharge tray 23
It is discharged to 3.

The recording sheet sent from the sheet supply tray 73 is a special sheet containing coated paper, cardboard, etc.
Since it is sent from 0 to the image forming unit 21 side, it is conveyed to the secondary transfer portion without particularly bending deformation or jamming.

In such an operation process, focusing on the post-processing unit 23, the sheet discharge tray 233 of the post-processing unit 23 is provided corresponding to the outlet opening 232, and the position of the sheet discharge tray 233 is recorded by the user. Since the sheet can be set at a position where it can be easily handled, the handling of the recording sheet can be kept good. In addition, the entrance opening 23
If the first position is set to a sufficiently lower position, the length of the inclined conveying path 234 is set to be sufficiently long, and the length of the inclined conveying path 234 in the inclined conveying path 234 located before and after the curl correction devices 235 and 236 is increased. Even if the recording sheet jams,
A sufficient jam processing space can be secured, and accordingly, the jam processing of the recording sheet can be easily realized. At this time, if the inclination degree of the inclined conveyance path 234 is set to a steep angle to some extent, the post-processing unit 2
3 (width dimension) in the direction of arrangement with the image forming unit 21
S can be sufficiently reduced.

Here, the first embodiment of the comparison shown in FIG. 4 will be described.
Reference numeral 3 'designates an opening 241 (corresponding to the discharge opening 212 of the image forming unit 21') and an outlet opening 242, respectively, at corresponding positions in the upper half of the post-processing unit 23 ', and between the openings 241 and 242. A horizontal transport path 244 extending substantially horizontally is provided, and curling correction devices 245 and 246 for removing upper curls and removing down curls are provided at two branch portions of the horizontal transport path 244, for example. If a sufficient length of the path 244 is to be ensured, the dimension S ′ of the post-processing unit 23 ′ in the arrangement direction with the image forming unit 21 ′ becomes unnecessarily large as compared with the dimension S of the present embodiment. In FIG. 4, reference numeral 243 denotes a sheet discharge tray, and 247 to 249 denote transport rolls.

Second Embodiment FIG. 5 shows an image forming apparatus according to a second embodiment of the present invention.
5 is an explanatory diagram showing a main part of the sheet conveying path around the fixing device 60 of the image forming unit 21 to the post-processing unit 23. FIG. In the figure, the basic configuration of an image forming apparatus according to the present embodiment is substantially the same as that of the first embodiment, in which a recording sheet on which an image is transferred on one side or both sides is fixed by a fixing unit 60, and then the image formation is performed. The unit 21 is fed into the post-processing unit 23 connected to the outlet 211 of the unit 21. Here, the post-processing unit 23 is located at a position corresponding to the discharge port 211 provided slightly below the image forming unit 21, at a position corresponding to the unit case 230.
Has an entrance opening 231 (in this example, a predetermined position that is less than half H / 2 of the height dimension H of the post-processing unit 23), while the operator slightly above the unit case 230 on the opposite side of the image forming unit 21 from the operator. An outlet opening 232 (in this example, a predetermined position of a portion exceeding half a height H / 2 of the height H of the post-processing unit 23) is provided at a position where the recording sheet can be easily taken, and is located between the inlet opening 231 and the outlet opening 232. An inclined conveying path 234 is formed in the oblique direction. The inclined conveying path 234 is branched into two in the middle, and each of the branched conveying paths is provided with a curl correcting device 235, 23 for correcting an up-curl or a down-curl.
6 is provided.

Further, in the present embodiment, the fixing device 60
For example, a heat roll 601 having a built-in heater, and a fixing belt 602 pressed against the heat roll 601
The recording sheet is sandwiched in the fixing nip area a between the two and heat and pressure are applied to fix the image on the recording sheet. On the other hand, the curl correcting devices 235 and 236 provided in the post-processing unit 23 include, for example, decurler shafts 251 and 253 and decurler belts 252 and 254 that are pressed against the decurler shafts 251 and 253, respectively. At b2, the recording sheet is nipped and pressure is applied to correct the curl of the recording sheet. In particular, in this embodiment, if the sheet conveying path length between the fixing nip area a of the fixing device 60 and the post-processing nip areas b1 and b2 of the curl correction devices 235 and 236 is L1 and L2, the sheet conveying The path lengths L1 and L2 are set to be longer than the length of the recording sheet of the maximum usable size that can be conveyed by the image forming apparatus in the conveying direction, and the fixing nip area a of the fixing unit 60 is set.
Nip conveyance of recording sheet and curl correction device 2
The nip conveyance of the recording sheet in the post-processing nip areas b1 and b2 of 35 and 236 is not performed simultaneously on the same recording sheet.

Therefore, according to the present embodiment, similarly to the first embodiment, the curl correcting devices 235 and 236 are provided on the inclined conveyance path 234 that crosses upward from below the unit case 230 of the post-processing unit 23. Since they are arranged in the middle, the space in the post-processing unit 23 can be effectively used, and the width S of the post-processing unit 23 can be reduced. The entrance opening (sheet entrance) 231 of the post-processing unit 23 and the curl correction device 235
236 and a sheet conveying path connecting the curl correcting device 2
Since a long sheet conveyance path connecting the outlets 35 and 236 and the outlet opening (sheet discharge port) 232 of the post-processing unit 23 can be ensured, a sufficient space for jam clearance of the paper recording sheet at that location can be ensured. It is possible to improve the jam operability.

Further, in the present embodiment, one recording sheet is fixed to the fixing nip area a of the fixing device 60 and the curl correcting device 23.
5 or 236, the recording sheet is not conveyed across the post-processing nip area b1 or b2. Therefore, the nip conveyance of the recording sheet by the fixing nip area a and the recording sheet by the post-processing nip area b1 or b2 are not performed. Even if there is a difference in the conveyance speed of the recording sheet between the nip conveyance and the nip conveyance, the recording sheet will not be damaged by tension or the like. Furthermore, since the curl correcting devices 235 and 236 are disposed at positions sufficiently separated from the fixing device 60 that applies heat to the recording sheet, the recording sheet that has passed through the fixing device 60 is gradually cooled by conveyance. In this state, the recording sheet reaches the curl correcting devices 235 and 236. When the curl amount of the recording sheet, which gradually changes after fixing, is stabilized, the curl is corrected, and the curl is corrected with a correction value suitable for the stable curl amount. Corrections can be performed.

Here, the second embodiment shown in FIG. 6 will be described.
1 ′ has a recording sheet discharge port 212 in the upper half thereof, and an inlet opening 241 and an outlet opening 242 are respectively opened in the upper half of the post-processing unit 23 ′ corresponding to the discharge port 212. Horizontal conveyance path 244 extending substantially horizontally between 242
, And curl correcting devices 245 and 246 for removing upper curls and removing down curls, for example, are disposed at two branch portions of the horizontal transport path 244. In the second comparative example, the heat roll 6 of the fixing device 60 is
A ′ is the fixing nip area between the fixing belt 01 and the fixing belt 602, and the decurler shaft 26 of each of the curl correcting devices 245 and 246.
The post-processing nip areas between the first and second decals 262 and 264 are b1 'and b2', respectively, and the fixing nip area a '
If the length of the sheet conveyance path between the first and second post-processing nip areas b1 'and b2' is L1 'and L2', the sheet conveyance path length L1 'and
L2 ′ is set to be longer than the maximum length of the recording sheet that can be transported by the image forming apparatus in the transport direction, and the nip transport of the recording sheet by the fixing nip area a ′ and the recording by the post-processing nip areas b1 ′ and b2 ′. When the nip conveyance of the sheet is not performed simultaneously on the same recording sheet, the width S ′ of the post-processing unit 23 ′ is set to be larger than the width S of the post-processing unit 23 shown in FIG. I have no choice. For this reason, the size of the post-processing unit 23 is reduced, and
It is understood that the mode shown in the second embodiment is preferable in terms of achieving both good post-processing conditions for the recording sheet.

[0033]

As described above, according to one aspect of the present invention, in an aspect in which a post-processing unit is attached to an image forming unit, an entrance opening is opened in the lower half of the post-processing unit, and An outlet opening is provided in the upper half of the processing unit, an inclined conveying path is secured between them, and a post-processing device is arranged in the middle of the inclined conveying path, so that the recording sheet can be easily handled. The exit opening can be selected in consideration of the above, and the length of the inclined conveyance path can be set sufficiently long even when the size of the post-processing unit in the direction of arrangement with the image forming unit is suppressed. Therefore, the size of the post-processing unit can be easily reduced while maintaining good handling of the recording sheet.

According to another aspect of the present invention, the length of the sheet conveying path between the fixing portion of the fixing device and the post-processing portion of the post-processing device is set to be longer than the maximum size sheet length used by the image forming apparatus. Thus, it is possible to avoid a situation where one recording sheet is conveyed across the fixing device and the post-processing device. For this reason, it is possible to reliably prevent damage due to pulling of the recording sheet due to a difference in transport speed between the fixing device and the post-processing device, and even when the post-processing device is a curl correction device, for example. After the fixing, the recording sheet can reach the decurling device under the condition that the recording sheet is sufficiently cooled during conveyance, and accordingly, the curl amount of the recording sheet is stabilized and the curl amount is appropriately corrected. Correction can be performed, and the post-processing condition by the post-processing device can always be kept good.

As described above, according to the present invention, it is possible to provide an image forming apparatus in which a post-processing unit arranged in parallel with an image forming unit is optimized and a post-processing unit used for the same.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of an image forming apparatus according to the present invention and a post-processing unit used therein.

FIG. 2 is an explanatory diagram illustrating an overall configuration of the image forming apparatus according to the first embodiment;

FIG. 3 is an explanatory diagram illustrating details of a post-processing unit used in the first embodiment.

FIG. 4 is an explanatory diagram illustrating an example of a sheet supply unit according to a first comparative example.

FIG. 5 is an explanatory diagram illustrating an overall configuration of an image forming apparatus according to a second embodiment.

FIG. 6 is an explanatory diagram illustrating an example of a sheet supply unit according to a second comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming unit, 2 ... Image forming module, 2a ... Sheet return conveyance mechanism, 2b ... Fixing device, 3 ... Post-processing unit, 3a ... Unit case, 5 ... Recording sheet, 6 ...
Discharge opening, 7: inlet opening, 8: outlet opening, 9: inclined conveying path, 10: post-processing device, L: sheet conveying path length between the fixing part of fixing device 2b and the post-processing part of post-processing device 10.

Claims (4)

[Claims] 1. An image forming unit in which an image forming module for forming an image on a supplied recording sheet is housed, and an image-formed recording unit arranged in parallel with the image forming unit and discharged from the image forming unit. A post-processing unit for performing post-processing on the sheet, wherein the post-processing unit has an inlet opening corresponding to a discharge opening on the image forming unit side in a lower half portion of the unit case on the image forming unit side, and a unit case. An outlet opening is provided in the upper half part on the opposite side of the image forming unit, an inclined conveying path is provided between the inlet opening and the outlet opening, and a post-processing device is provided in the middle of the inclined conveying path. Characteristic image forming apparatus. 2. An image forming apparatus comprising an image forming unit accommodating an image forming module for forming an image on a supplied recording sheet, wherein the image forming unit is arranged in parallel with the image forming unit and is provided from the image forming unit. A post-processing unit for performing post-processing on the discharged image-formed recording sheet, wherein an entrance opening is provided in the lower half of the unit case on the image forming unit side, and the unit case is on the opposite side of the image forming unit. A post-processing unit, wherein an outlet opening is provided in an upper half portion, an inclined conveying path is provided between the inlet opening and the outlet opening, and a post-processing device is provided in the middle of the inclined conveying path. 3. An image forming unit which houses an image forming module for forming an image on a supplied recording sheet and includes a fixing device for fixing an image on the recording sheet; A post-processing unit for performing post-processing by a post-processing device on a recording sheet on which an image has been created and discharged from the image forming unit and arranged in parallel with the forming unit; An image forming apparatus, wherein a length of a sheet conveying path between a part and a part is set to be longer than a maximum usable sheet length. 4. An image forming apparatus which contains an image forming module for forming an image on a supplied recording sheet and includes an image forming unit including a fixing device for fixing an image on the recording sheet. A post-processing unit that is used in a forming apparatus, and that performs post-processing by a post-processing device on an image-formed recording sheet that is arranged in parallel with the image forming unit and that is discharged from the image forming unit; A post-processing unit, wherein a sheet conveying path length between a part and a post-processing part of a post-processing device is set to be longer than a maximum size sheet length to be used.