JP2003312937A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device, which can drop and load sheets discharged from a post-treatment device on a discharge loading part of a body, and can be used by any user with operability similar to that of a conventional image forming device, even if the post-treatment device is additionally mounted on a top of the device body. <P>SOLUTION: For achieving the purpose, according to a representative structure of this image forming device, this image forming device comprises a discharge loading part arranged at a top of the device body; a loading sensing sensor flag projecting at the discharge loading part and contacting with top faces of the discharged sheets; the post-treatment device for applying a predetermined post-treatment to the sheets and discharging the sheets above the discharge loading part. The sheets discharged from the post-treatment device can be dropped onto the discharge loading part of the device body. This device is also equipped with a retreating means for retreating the loading sensing sensor flag out of a drop area of the dropping sheets, when the sheets are dropped onto the discharge loading part. <P>COPYRIGHT: (C)2004,JPO

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 in particular, an image having a detecting means for detecting a stacking state of discharged sheets and a post-processing means for performing a predetermined post-processing on the sheets. The present invention relates to a forming device.

[0002]

2. Description of the Related Art In recent years, image forming apparatuses such as laser printers as well as copying machines have been improved in performance by adding post-processing devices such as stapling and job separation to discharged sheets as needed. The trend is toward increasing the added value of the system. As a basic output form of the image forming apparatus, in order to output from the first page, a type having a stacking unit for face-down discharge (discharge with the recording surface facing down) is often adopted in the upper part of the main body. This type has an advantage that the installation area of the discharging device is not increased, and this idea is followed by the post-processing device and tends to be mounted on the upper part of the main body.

A conventional image forming apparatus having a post-processing apparatus on the upper portion of the apparatus will be described with reference to FIGS. 9 to 11. 9 is an overall configuration diagram of an image forming apparatus according to a conventional example, FIG. 10 is a schematic cross-sectional view of a post-processing apparatus, and FIG. 11 is a plan view of a main part of the post-processing apparatus.

In FIG. 9, an image forming apparatus main body 101 feeds a sheet from a feeding cassette 102 by a feeding roller 103 to a process cartridge 104 which is an image forming means.
In the process cartridge 104, an electrostatic latent image is formed by a laser scanner 105 on a photosensitive drum (not shown),
This is developed to form a toner image and transferred to the fed sheet. The sheet is heated and pressed by the fixing device 106 to fix the image, and is discharged to the discharge stacking unit 107 by the discharge roller 108 and the discharge roller 109.

The discharge stacking unit 107 is provided with a stacking detection sensor flag 110 for detecting the stacking state. The stacking detection sensor flag 110 is rotatable, and its tip extends long as an arm 110a so as to contact the stacking surface of the discharged sheets. Then, the flag portion 110b provided in the vicinity of the rear end is detected by the detection sensor 111, so that the height of the stacked sheets reaches a predetermined height (for example, the height h indicated by the two-dot chain line in the figure). I can know that.

A post-processing device can be additionally installed on the upper part of the image forming apparatus main body 101. In this conventional example, the staple stacker 120 will be described as an example of the post-processing device. Near the discharge section of the image forming apparatus, the conveyance path is bifurcated so that the sheet can be conveyed to the post-processing apparatus.
The conveyance path can be selectively switched by the 112 and the solenoid 113.

As shown in FIG. 10, the staple stacker 12
When the conveyance path is switched to the 0 side, the sheets are temporarily aligned by the introduction roller pair 121 provided on the stacker side, the conveyance path 123, the discharge roller pair 124, and the alignment trays 126 and 127.
Is discharged to.

As shown in FIG. 11, the alignment trays are arranged so as to face each other, and a space is provided between them. In addition, the alignment trays 126 and 127 have a shaft portion 126a.
The aligning tray 127 can be rotated downward by the shaft portions 127a so as to widen the space. This rotating means can be realized by combining a stepping motor or solenoid (not shown) with a rack or gear. In addition, the alignment trays 126 and 127 have an inverted "F" shape in the transport direction, and positively stiffen the sheets to prevent the sheets from being accidentally dropped from the central portion of the alignment trays. There is.

Near the discharge portion of the staple stacker 120, a rear end pressing member for preventing the rear end of the sheet from floating.
128 is installed. A matching plate 129 is provided above the matching trays 126 and 127. The alignment plate 129 has an inverted L shape, one end overlaps with one alignment tray 126, and the other end forms a rack portion 129 a, which is driven by a stepping motor 132. Alignment plate 129 is an alignment tray
The sheets discharged onto the sheets 126 and 127 are operated by a predetermined amount for each sheet size, and the abutting end face 127b of the alignment tray 127 is moved.
To match. After a predetermined number of sheets temporarily ejected to the alignment trays 126 and 127 have been ejected and aligned, the alignment tray 127
The stapling unit 130 provided near the side discharge port performs the stapling process at the stapling position 130a near the sheet corner. After that, the aligning trays 126 and 127 rotate downward so as to expand the space, and the sheet bundle on the aligning trays 126 and 127 is dropped and stacked on the stack tray 131 of the post-processing apparatus.

[0010]

The configuration in which the additional post-processing device is installed on the upper part of the main body as in the above-described conventional example is an excellent configuration in that the installation area is not increased and the function can be easily expanded. is there. However, it has a disadvantage that the height of the discharge stacking section becomes high like the stack tray 131 of the conventional example. Since many image forming apparatuses in this class are used as desktop machines, the height for taking out the output sheet is basically high. In addition, the space between the device body and the post-processing device must be sufficiently provided so as not to impair the operability of the device body, but in many cases an additional feeding device is attached to the lower part of the device, Along with that, the loading capacity of the upper part of the main body also increases, and the height of the discharge loading section of the post-processing device tends to further increase. On the other hand, in the case of the accessibility law for people with disabilities, the height of the post-processing device, especially the height of the discharge stacking part when used as a tabletop machine, will be subject to more severe conditions.

There are several possible ways to solve this problem, but it is preferable to use a desk-top machine by dropping it into the discharge stacking section of the printer body. However, even if the discharge stacking unit (stack tray 131) is not provided in the post-processing device (staple stacker 120) and the stacking unit 107 is dropped onto the discharge stacking unit 107 of the apparatus body, the stacking detection sensor flag 110 on the discharge stacking unit 107 interferes. Then, there is a problem that it is not loaded normally. In this case, it may be considered that the stacking detection sensor flag 110 is not provided in the discharge stacking unit 107, but if the printers are shared by a plurality of users, or if there is a possibility that a large amount of printing may be performed, the status of each printer may be changed. It has become an indispensable structure for grasping by the user's PC.

For these reasons, some products have a height that does not conform to the accessibility law, some products have a reduced height at the expense of the operability of the apparatus body, and a special pedestal (floor stand) is prepared. I did not install it on the table.

Therefore, according to the present invention, even if a post-processing device is additionally mounted on the upper part of the main body of the apparatus, the sheets discharged from the post-processing apparatus can be dropped and stacked on the discharge stacking section of the main body, and any user can use the conventional image. An object of the present invention is to provide an image forming apparatus that can be used with the same operability as that of the forming apparatus.

[0014]

In order to solve the above-mentioned problems, a typical structure of an image forming apparatus according to the present invention has a discharge stacking section arranged at the upper part of the apparatus main body and a discharge stacking section projecting to the discharge stacking section. Stacking detection sensor flag that abuts the upper surface of the formed sheet, a detection sensor that can detect the stacking detection sensor flag, and a post-processing device that performs predetermined post-processing on the sheet and discharges the sheet above the discharge stacking unit. In the image forming apparatus having the above, the sheet discharged from the post-processing apparatus can be dropped onto the discharge stacking section of the apparatus main body, and when the sheet is dropped onto the discharge stacking section, the stack detection sensor flag is dropped. It is characterized in that a retracting means for retracting the sheet to the outside of the falling area is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment A first embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of an image forming apparatus according to the present embodiment, FIG. 2 is a schematic cross-sectional view of a post-processing apparatus, FIG. 3 is a plan view of a main portion of the post-processing apparatus, and FIG. 4 is a retracting operation of a stacking detection sensor flag. It is a flowchart explaining.

In FIG. 1, the image forming apparatus main body 1 feeds a sheet from a feeding cassette 2 by a feeding roller 3 to a process cartridge 4 which is an image forming means. In the process cartridge 4, a laser scanner 5 forms an electrostatic latent image on a photosensitive drum (not shown), and the electrostatic latent image is developed to form a toner image, which is transferred to a fed sheet.
The sheet is heated and pressed by the fixing device 6 to fix the image, and is discharged to the discharge stacking unit 7 by the discharge roller 8 and the discharge roller 9.

As shown in FIG. 2 (a), the discharge stacking unit 7 is provided with a stacking detection sensor flag 10 for detecting the stacking state. The stacking detection sensor flag 10 is rotatable, and its tip extends long as an arm 10a so as to contact the stacking surface of the discharged sheets. Then, the flag portion 10b provided in the vicinity of the rear end is detected by the detection sensor 11, so that the height of the stacked sheets becomes a predetermined height (for example, the height h shown by the two-dot chain line in the figure). I can know that.

A post-processing device can be additionally installed on the upper portion of the image forming apparatus main body 1. In this conventional example, the staple stacker 12 will be described as an example of the post-processing device. A conveyance path is bifurcated near the discharge portion of the image forming apparatus so that the sheet can be conveyed to the post-processing apparatus, and the conveyance path can be selectively switched by the flapper 13 and the solenoid 14.

When the conveying path is switched to the staple stacker 12 side, the sheet is ejected through the conveying path 23 by the introducing roller pair 21 provided on the stacker side and the discharging roller pair 24.
And is temporarily discharged to the alignment trays 26 and 27.

As shown in FIG. 3, this alignment tray 26, 27
Are arranged to face each other, and a space is provided between them. In addition, the alignment trays 26, 27 are
At 26a, the alignment tray 27 can be rotated downward by the shaft portions 27a so as to widen the space. This rotating means can be realized by combining a stepping motor or solenoid (not shown) with a rack or gear. In addition, the alignment trays 26 and 27 have an inverted "F" shape in the conveying direction, and positively stiffen the sheets to prevent the sheets from being accidentally dropped from the central portion of the alignment trays. There is.

Near the discharge section of the staple stacker 12,
A rear end pressing member 28 is mounted for the purpose of preventing the rear end of the seat from floating. An alignment plate 29 is provided above the alignment trays 26 and 27.
Is provided. The aligning plate 29 has an inverted L shape, one end thereof overlaps with one aligning tray 26, and the other end forms a rack portion 29a, which is driven by a stepping motor 32. The aligning plate 29 operates a predetermined amount for each sheet size with respect to the sheets discharged on the aligning trays 26 and 27,
The abutting end surface 27b of the aligning tray 27 is aligned. After a predetermined number of sheets temporarily ejected to the alignment trays 26 and 27 have been ejected and aligned, the stapler unit 30 provided near the ejection port on the alignment tray 27 side performs binding processing to the binding position 30a near the corners of the sheets. Be seen.

After that, the alignment trays 26 and 27 rotate downward so as to widen the space, and the sheet bundles on the alignment trays 26 and 27 are dropped and stacked on the discharge stacking unit 7 of the image forming apparatus main body 1. . Here, if you simply drop the sheet bundle,
Since the arm 10a of the stacking detection sensor flag 10 provided in the discharge stacking unit 7 extends in the sheet drop area, the sheet bundle is dropped and stacked on the arm 10a, and the stacking cannot be performed normally. It becomes impossible to detect the loading.

Therefore, in the present embodiment, the image forming apparatus main body 1 is provided with a stack detection solenoid 15 as a retracting means for the stack detection sensor flag 10. Loading detection solenoid
Reference numeral 15 is provided in the image forming apparatus main body 1 and operates in accordance with the ejection control of the staple stacker 12. The actuator leading end 16 of the stacking detection solenoid 15 is formed in an L shape, and contacts and acts on the rear end 10c of the stacking detection sensor flag 10 in only one direction to rotate the stacking detection sensor flag 10.
Is configured to retract to the outside of the falling area of the falling sheet.

Specifically, as shown in FIG. 2A, when the stack detection solenoid 15 is in the OFF state, the stack detection sensor flag is set.
The normal operation of 10 is not restricted, and when it is in the ON state as shown in FIG. 2 (b), the rear end 10c of the stacking detection sensor flag 10 is pressed to rotate it to the position 10c 'in the figure. Since the rear end 10c is formed integrally with the stacking detection sensor flag 10, the stacking detection sensor flag 10 is thereby rotated to the retracted position 10 'inside the regulation wall surface 31.

The retracting operation of the stacking detection sensor flag will be described with reference to FIG. First, the image formation command (Print Comman
When (d) is sent (S1), it is judged whether or not the job requires post-processing (S2), and if it is unnecessary, the process is terminated (S).
3). When performing the post-processing, the flapper 13 is opened to guide the sheet to the staple stacker 12 (S4), and the alignment tray 2
Matching is performed on 6 and 27 (S5). Then, it is determined whether or not the sheet bundle to be processed is the last (S6), and if not, the next image forming command is awaited (S1). If the last sheet of the sheet bundle is aligned (S6), it is determined whether or not stapling is to be performed as post-processing (S7), and if it is to be performed, it is executed (S8).

Then, the sheet bundle is discharged to the discharge stacking section 7. First, the stack detection solenoid 15 is turned on (S
9), the stacking detection sensor flag 10 is rotated inside the regulation wall surface 31. Then, the alignment trays 26 and 27 are rotated to open them, and the sheet bundle is dropped (S10). As a result, the sheet bundle falls on the discharge stacking unit 7 of the image forming apparatus main body 1. However, since the stacking detection sensor flag 10 is retracted from the falling area of the sheet, the sheet bundle is stacked on the stacking detection sensor flag 10.
It is loaded on the discharge stacking unit 7 without being caught by. After that, the alignment trays 26 and 27 are closed (S11), the stack detection solenoid 15 is turned off (S12), and the regulation of the stack detection sensor flag 10 is released to enable normal stack detection.

With the above configuration, the sheet can be discharged from the post-processing device to the discharge stacking unit of the apparatus body without impairing the function of the stack detection sensor of the image forming apparatus body. As a result, the height at which the sheet output from the post-processing device is taken out does not increase, and a sufficient space can be secured between the main body of the device and the post-processing device, so that the accessibility method is not impaired. It is possible to provide an image forming apparatus conforming to.

Second Embodiment A second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. Figure 5
6 is an overall configuration diagram of the image forming apparatus according to the present exemplary embodiment, FIG. 6 is a schematic cross-sectional view of the post-processing apparatus according to the present exemplary embodiment, and the same portions as those of the first exemplary embodiment are denoted by the same reference numerals. The description is omitted.

In the first embodiment described above, the stacking detection solenoid 15 as the retracting means is provided on the image forming apparatus main body 1 side, but in the present embodiment, the retracting means is provided on the staple stacker 12 side as the post-processing apparatus. It is a thing.

As shown in FIG. 5, the staple stacker 12 as a post-processing device discharges and stacks sheets on the discharge stacking unit 7 of the image forming apparatus main body 1 as in the first embodiment. As shown in FIG. 6 (a), in the present embodiment, the stacking detection solenoid 40 as a retracting means is a staple stacker.
It is provided on the 12 side, and its actuator tip 41 is L
It is formed in a character shape and enters the inside of the upper portion of the image forming apparatus main body 1, and contacts the rear end 10c of the stacking detection sensor flag 10 in only one direction and acts to rotate the stacking detection sensor flag.
It is configured to retract 10 to the outside of the falling area of the falling sheet.

When the stacking detection solenoid 40 is in the OFF state as shown in FIG. 6 (a), the normal operation of the stacking detection sensor flag 10 is not restricted, and when it is in the ON state as shown in FIG. 6 (b). Presses the stacking detection sensor flag 10 and rotates it to the position 10c 'in the figure. Since the rear end 10c is formed integrally with the stack detection sensor flag 10, the stack detection sensor flag 10 is thereby rotated to the retracted position 10 'inside the regulation wall surface 31. After that, the alignment trays 26 and 27 rotate downward so as to widen the space, so that the sheet bundles on the alignment trays 26 and 27 fall on the discharge stacking unit 7 at the upper part of the image forming apparatus main body 1. Since the sensor flag 10 enters the inside of the regulation wall surface 31, the end face of the sheet bundle is the stack detection sensor flag.
It is loaded without being caught in 10.

With the above configuration, it is not necessary to add a configuration for the post-processing device to the image forming apparatus main body as the minimum configuration, and it is possible to prevent an increase in the production cost of the image forming apparatus main body. Further, since the stack detection solenoid operates in accordance with the discharge control of the staple stacker 12 which is the post-processing device, the control mechanism can be simplified as compared with the case where it is provided in the image forming apparatus main body 1.

[Third Embodiment] A third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. Figure 7
FIG. 8 is a schematic cross-sectional view of the post-processing device according to the present embodiment, FIG. 8 is a diagram for explaining the operation of the evacuation unit, and the same parts as those in the first embodiment will be designated by the same reference numerals and described. Is omitted.

In each of the above-described embodiments, both the stacking detection solenoid 15 and the stacking detection solenoid 40 as the retracting means are retracted by further rotating the stacking detection sensor flag 10 using the original rotating mechanism. However, in the present embodiment, the stack detection sensor flag is retracted by rotating the rotation shaft itself of the stack detection sensor flag.

As shown in FIG. 7, the stacking detection sensor flag 52 according to the present embodiment is rotatable about a flag rotation shaft 54b, and its tip comes into contact with the stacking surface of discharged sheets. The arm 52a extends for a long time. arm
Ribs for reinforcement are provided on the curved inner side of 52a. The flag portion 52b provided at the rear end is the sensor
As a result of being detected by 53, the height of the stacked sheets is a predetermined height (for example, the height h shown by the chain double-dashed line in the figure).
You can know that.

The flag rotating shaft 54b is arranged at one end of the link member 54, and the link member 54 is rotatable around the link rotating shaft 54a. Further, an action shaft 54c is provided at the other end of the link member 54. Further, an elastic member 58 such as a coil spring is attached to the link member 54, and biases the link member 54 so that the stacking detection sensor flag 52 is located at the initial position. A stopper 56 for stopping the lowering of the link member 54 is provided at the lower portion of the staple stacker 12, and the rotation angle is regulated so that the link member 54 does not fall too much.

A stacking detection solenoid 50 as a retracting means is provided in the staple stacker 12, its actuator tip 51 is formed in an L-shape, and a working shaft 54 of a link member 54.
It is configured to contact and act on c in only one direction to rotate the link member 54. The staple stacker 12 is provided with a regulation portion 55 such as a rib that regulates the rotation of the action shaft 54c, and regulates the rotation angle of the link member 54.

With the above structure, when the stacking detection solenoid 50 is turned on as shown in FIG. 8, the action shaft 54c is rotated to the position 54c 'in the figure. As a result, the link member 54 formed integrally with the action shaft 54c is rotated to move the flag rotation shaft 54b to the position 54b ', whereby the entire arm 52a is moved to the retracted position 52a' inside the staple stacker 12. Is stored. At this time, the stacking detection sensor flag 52 has its posture 52 ′ regulated by the regulation portion 57 provided in the staple stacker 12 to prevent the arm 52a from jumping out to the drop area. Therefore, the arm 52a of the stacking detection sensor flag 52 retreats out of the drop area of the sheet falling from the staple stacker 12, and the stacking from the staple stacker 12 to the discharge stacking unit 7 of the image forming apparatus main body 1 becomes possible.

When the stack detection solenoid 50 is turned off, the link member 54 is urged by the elastic member 58 to move to the initial state and detects the height of the sheets stacked on the discharge stacking unit 7 as usual. It becomes possible.

With the above configuration, when the stacking detection sensor flag is retracted, it does not pass through the sheet drop area, so that the interval when the sheet is discharged can be shortened.
The discharge processing can be speeded up.

In the above embodiment, the stapler tacker having the stapler unit is used as the post-processing device, but the punching unit for punching at a predetermined position, the sorter for dividing jobs, or the like is used. Also, the effect can be obtained by applying the present invention.

[0042]

As described above, in the image forming apparatus according to the present invention, the stacking detection sensor flag of the discharge stacking unit provided in the upper part of the apparatus main body can be retracted from the drop area of the sheet falling from the post-processing apparatus. By doing so, it is possible to discharge the sheet from the post-processing device to the discharge stacking unit of the apparatus body without impairing the function of the stacking detection sensor of the image forming apparatus body.

As a result, it becomes an indispensable item for grasping the status of the printer by each user's personal computer such as when the printer is shared by a plurality of users or when there is a possibility that a large amount of printing may be performed. Even if the post-processing device is additionally installed on top of the image forming device used as a desktop machine while maintaining the function of the stacking detection sensor flag of the coming printer body, the sheet output from the post-processing device is The height for taking out does not become high, and a sufficient space can be secured between the apparatus main body and the post-processing apparatus. Therefore, it is possible to provide an image forming apparatus conforming to the accessibility method without impairing the operability for the user.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a schematic cross-sectional view of a post-processing device according to the first embodiment.

FIG. 3 is a main part plan view of the post-processing device according to the first embodiment.

FIG. 4 is a flowchart illustrating a stacking detection sensor flag retracting operation according to the first embodiment.

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

FIG. 6 is a schematic cross-sectional view of a post-processing device according to a second embodiment.

FIG. 7 is a schematic cross-sectional view of a post-processing device according to a third embodiment.

FIG. 8 is a diagram for explaining the operation of the evacuation means according to the third embodiment.

FIG. 9 is an overall configuration diagram of an image forming apparatus according to a conventional example.

FIG. 10 is a schematic cross-sectional view of a post-processing apparatus according to a conventional example.

FIG. 11 is a plan view of a main part of the post-processing device.

[Explanation of symbols]

1 ... Image forming apparatus main body 2 ... Feed cassette 3 ... Feed roller 4 ... Process cartridge 5 ... Laser scanner 6 ... Fixer 7 ... Discharging and loading section 8 ... Ejection roller 9… Ejection roller 10… Load detection sensor flag 10a ... Arm 10b ... Flag section 10c ... rear end 11… Detection sensor 12 ... Staple stacker 13 ... flapper 14 ... Solenoid 15… Loading detection solenoid 16… Actuator tip 21… Introduction roller pair 23 ... Transport path 24… Ejection roller pair 26… Alignment tray 26a ... Shaft 27… Alignment tray 27a ... Shaft 27b ... End face 28 ... Rear end pressing member 29… Matching plate 29a… Rack part 30… Stapler unit 30a ... Binding position 31… Regulation wall 32… Stepping motor 40… Loading detection solenoid 41 ... Actuator tip 50… Loading detection solenoid 51… Actuator tip 52… Load detection sensor flag 52a ... Arm 52b ... Flag section 53… Sensor 54… Link member 54a ... Link rotation axis 54b ... Flag rotation axis 54c… acting axis 55… Regulation Department 56… Stopper 57… Regulation Department 58… Elastic member 101 ... Image forming apparatus main body 102… Feed cassette 103… Feeding roller 104… Process cartridge 105… Laser scanner 106… Fixer 107… Discharge loading section 108… Ejection roller 109… Ejection roller 110… Load detection sensor flag 110a ... Arm 110b ... Flag part 111… Sensor 112 ... flapper 113… Solenoid 120 ... Staple stacker 121… Introduction roller pair 123 ... Transport path 124… Ejection roller pair 126… Alignment tray 126, 127… Alignment tray 126a ... Shaft 127… Alignment tray 127a ... Shaft 127b ... Abutting end face 128 ... Rear end pressing member 129… Matching plate 129a ... Rack section 130 ... Stapler unit 130a… Position 131… Stack tray 132… Stepping motor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/00 534 H04N 1/00 108Q 5C062 H04N 1/00 108 B41J 29/00 H (72) Izumi Izumi Makoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Nobuyuki Uchiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2C061 AQ06 BB08 BB35 CK04 2H072 AA09 AA17 AA28 FB01 GA08 3F048 AA02 AA05 AB01 BA04 BB10 DA09 DC10 DC13 EB40 3F054 AA01 AC02 AC05 BA04 BB12 BC11 BG02 BG11 CA11 CA22 DA01 3F108 GA02 GA01 GA04 GB01 HA02 HA39 HA44 5C0653 AC01 AB01 AB05 AB01

Claims (4)

[Claims] 1. A discharge stacking unit disposed on an upper part of the apparatus main body, a stacking detection sensor flag that abuts an upper surface of a sheet that is projected and discharged to the discharge stacking unit, and a detection sensor that can detect the stacking detection sensor flag. An image forming apparatus that performs predetermined post-processing on a sheet and discharges the sheet above the discharge stacking unit, wherein the sheet discharged from the post-processing device is discharged onto the discharge stacking unit of the apparatus main body. An image forming apparatus, which is capable of dropping, and is provided with a retracting unit that retracts the stacking detection sensor flag to a position outside a falling area of a falling sheet when the sheet is dropped on the discharge stacking unit. 2. The post-processing apparatus is removable from the main body of the image forming apparatus, and a post-processing apparatus that performs different post-processing is selectively mounted or not mounted. Image forming apparatus. 3. The evacuation unit is provided on the image forming apparatus main body side, and the stacking detection sensor flag is evacuated by operating the evacuation unit in accordance with the ejection control of the post-processing device. The image forming apparatus according to claim 1. 4. The evacuation means is provided on the side of the post-processing apparatus, and the evacuation means operates in accordance with ejection control of the post-processing apparatus to evacuate the stacking detection sensor flag. The image forming apparatus according to claim 1.