JPH0736299A - Structure of recording paper ejecting part - Google Patents

Abstract

PURPOSE:To provide a structure of recording paper ejecting part satisfactorily realizing paper ejection always providing adequate stiffness without curling, irrespective of the difference of paper kind such as paper thickness and material. CONSTITUTION:In an image forming device provided with a pair of the upper and the lower paper ejecting roller 13 and 14 at the paper ejecting port, the device is constituted so as to adjust the gap of the both paper ejecting roller 13 and 14 by moving one of the paper ejecting rollers in the up and down directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a mechanism for ejecting recording paper on which an image has been recorded in an image forming section of an image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine, a printer, and a facsimile apparatus has a structure for discharging a recording sheet on which an image has been formed onto a discharge tray, and is normally placed adjacent to a discharge port. It is configured to discharge the recording paper onto the paper discharge tray while nipping the recording paper by the arranged discharge roller pair. The paper discharge roller is configured to support the recording paper at the time of nip in order to prevent the discharged recording paper from being curled. Here, "stiffening" means that, by making the diameter of one or both of the discharge rollers axially different, a habit of curving in the direction orthogonal to the conveying direction is intentionally formed during paper passage, resulting in curl. Means to prevent.

However, when ejecting thick paper (for example, 135 k paper) and nipping the same by the pair of paper ejection rollers, streaky lines or other abnormalities are formed on the image, This causes deterioration of image quality.
From this point of view, it has been desired to develop an apparatus capable of realizing curl-free sheet discharge by always providing an appropriate waist regardless of the difference in the paper type such as paper thickness and material. In addition,
A technique for adjusting the discharge roller pressure to change the discharge direction (Japanese Utility Model Laid-Open No. 64-59246) and a structure for releasing the nip between the discharge rollers by opening the cover (Japanese Patent Laid-Open No. 63-192072). However, none of these solves the above-mentioned problems corresponding to changes in paper thickness, and is intended only for changing the conveying direction and for jamming, and therefore these configurations are not provided. Even if the above is applied, the above-mentioned problem cannot be solved.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and it is possible to realize a good curl-free discharge by always providing a proper waist irrespective of the difference in paper type such as paper thickness and material. It is an object of the present invention to provide the structure of the recording paper discharging unit.

[0005]

In order to achieve the above object, the present invention is an image forming apparatus having a pair of upper and lower paper discharge rollers at a paper discharge port, and one paper discharge roller is moved in the vertical direction to discharge both paper discharge sheets. In the image forming apparatus having a configuration in which the distance between the rollers can be adjusted, a pair of upper and lower discharge rollers are provided at the discharge port, and a fixing device is provided on the upstream side of the pair of discharge rollers. The upper and lower paper ejection guide plates are provided with the paper ejection path between the paper ejection roller pair interposed therebetween, and means for adsorbing the recording paper to one of the upper and lower paper ejection guide plates and a conveyor belt are provided. The image forming apparatus is provided with a discharge roller trace elimination mode, which is provided with a means for adsorbing the recording paper and a control unit for operating the conveyance belt only when the conveyance force of the discharge roller pair is below a predetermined value. Ejection roller trace elimination mode on the operation panel When the switch is turned on, the control section shifts to the discharge roller trace elimination mode to widen the distance between the discharge rollers, and when a sorter is connected to the discharge port, the discharge roller pair is changed to Always open
In an image forming apparatus having a pair of upper and lower paper discharge rollers at a paper discharge port and a fixing device upstream of the paper discharge roller pair, a paper discharge path between the fixing device and the paper discharge roller pair is sandwiched. And the upper and lower paper ejection guide plates are provided so that each paper ejection roller is concealed by the paper ejection guide plate when the paper ejection roller pair is completely opened. In an image forming apparatus including a paper discharge roller and a fixing device on the upstream side of the paper discharge roller pair, upper and lower paper discharge guide plates sandwiching a paper discharge path between the fixing device and the paper discharge roller pair. And a guide rib that guides the recording paper to the gap between the pair of discharge rollers when the pair of discharge rollers is completely opened.

The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. FIGS. 1 (a) and 1 (b) are a front view and a partial side view showing a configuration of an essential part of an embodiment of the present invention, and FIG. 2 is an operation explanatory view of FIG. The part shown in the figure is a structure of a fixing device of an image forming apparatus using an electrophotographic process and a paper discharge mechanism located on the downstream side of the fixing device, and an image forming unit centering on a photoconductor (not shown) is provided on the right side of the fixing device 1. The recording paper P on which the toner image has been transferred is positioned on the fixing roller 2
Then, the toner image is fixed by entering the nip portion of the pressure roller 3. The paper discharge mechanism 10 located on the downstream side of the fixing device includes an upper paper discharge guide plate 11 and a lower paper discharge guide plate 12 that guide the recording paper P discharged from the fixing device 1 to the downstream side.
And the driven-side upper discharge roller 13 and the drive-side lower discharge roller 14, and the like. The upper discharge guide plate 11 is supported rotatably in the vertical direction about a fulcrum 15 and The upper paper discharge roller 13 is rotatably supported at the tip of a holder 16 which is a leaf spring extending from the paper guide plate 11. As means for vertically moving the upper guide plate 11 and the like, FIG.
The solenoid 17 as shown in (b) is used, and the spring 18
Thus, the upper guide plate 11 is always urged downward, while the solenoid 17 is actuated to pull it up. By adjusting the protrusion length of the solenoid's plunger, it is possible to adjust the distance between the discharge rollers. The paper discharge roller pair has a structure for attaching the recording paper to the waist. Reference numeral 19 is a paper discharge tray, and 20 is a paper discharge cover. Reference numeral 21 shown in FIG. 2 is a separation claw.

FIG. 3 is a schematic view showing another means for vertically moving the upper sheet discharge guide plate. The cam 25 is arranged at a position facing the projection 11a provided at a proper lower portion of the upper guide plate 11. By rotating the cam automatically or manually, the cam 25 presses the protrusion 11a to raise it,
It is configured so that it can be released by pressing down. The upper sheet ejection guide plate in the embodiment of FIGS. 1 and 2 may be configured to be manually moved up and down. In this case, a part of the shaft member or the like protruding from the upper guide plate 11 may be external to the device. It may be configured so that it can be operated by protruding it.

According to the construction of the above-described embodiment, since the paper discharge roller which moves up and down integrally with the guide plate is provided, when the recording paper on which the image is formed is thick, it is previously discharged as shown in FIG. By adjusting the distance between the paper rollers to a large degree, it is possible to prevent the thick paper from being formed with streak lines by the paper discharge rollers and prevent deterioration of image quality. In the case of a normal type of recording paper, the upper and lower discharge rollers may be operated in a nipped state as shown in FIG.

FIG. 4 shows a modified embodiment in which the upper and lower guide plates 11 and 12 are fixed, while the holder 16 supporting the upper paper discharge roller 13 is pivotally movable by a portion other than the upper guide plate. It is characteristic that the holder is supported and the holder 17 is moved up and down by a solenoid 17. In this embodiment, the spacing adjustment according to the paper thickness can be realized by raising and lowering only the upper paper ejection guide plate alone, and the same effect as that of the above-described embodiment is obtained. By the way, in each of the above-described embodiments, a space is provided between the discharge roller pairs or the discharge rollers are completely opened. Therefore, the recording paper passing through the fixing nip portion loses the conveying force and is not conveyed to the discharge tray. It may be left in the machine body. For that purpose, it is one method to make the distance between the fixing device and the paper discharge tray as close as possible, but it may be difficult in terms of layout.

FIGS. 5 to 7 show an embodiment for solving such a problem, in which one of the upper and lower paper discharge guide plates is provided with a conveyor belt and a recording paper suction fan.
The recording paper is conveyed to the paper discharge tray. That is, as shown in FIG. 5, the paper discharge mechanism 10 is configured such that the upper paper discharge guide plate 11 and the upper paper discharge roller 13 can move up and down, while the lower paper discharge guide plate 12 has a conveyor belt 30 and a suction belt. The configuration in which the fan 31 is arranged is characteristic. The specific configurations of the conveyor belt and the suction fan are as shown in the enlarged views of FIGS. 6 and 7, and the upper surface of the lower paper ejection guide plate is partially open, so that the conveyor belt 30 housed therein is ejected downward. It is arranged so as to be vertically movable relative to the paper guide plate 12. In addition, the ventilation pipes 33 are arranged so as to penetrate the transportation belt (a plurality of narrow belts are arranged in parallel at a predetermined interval), and the lower end of each ventilation pipe 33 has a tubular body 34.
It is connected to the fan main body 35 arranged outside via. The upper end of the ventilation pipe opens at a position avoiding the belt 30 and faces the conveyance path of the recording paper. As the fan main body 35 is driven to rotate, a negative pressure is generated in the ventilation pipe 33, and the recording paper that is about to pass above the lower paper ejection guide plate 12 can be adsorbed.

FIG. 7 shows an example of a structure for vertically moving the conveyor belt 30 relative to the paper discharge guide plate. In this example, the conveyor belt side is fixed, and the lower paper discharge guide plate 12 is solenoid 40. By raising and lowering, the conveying surface of the conveying belt can be exposed or retracted. That is, when the pair of discharge rollers maintains the conveying force, the conveying belt 30 is retracted into the lower discharge guide plate 12 as shown in FIG. 6, but the conveying force is increased by opening the pair of conveying rollers. Solenoid 40 if lost
Is operated to lower the lower paper ejection guide plate 12 to expose the conveyor belt 30, and the recording paper is ejected to the paper ejection tray side in cooperation with the suction means. Although the guide plate side is moved in the above embodiment, the conveying belt side may be moved up and down. Moreover, the suction fan is shown in FIG.
It may be provided inside the guide plate as shown in FIG. 6 or may be provided outside as shown in FIG. Further, a mechanism including a suction fan and a conveyor belt may be provided on the upper guide plate side. In FIG. 7, the ventilation pipe and the like are omitted.

In this embodiment, when the suction fan and the conveyor belt are operated, for example, when the distance between the pair of conveyor rollers is such that the conveying force can be sufficiently maintained (for example, 10 gf or more), it does not operate. , When the distance between the pair of discharge rollers is widened and the carrying force is lost (for example, 10 gf
It should be controlled so that it operates only in the following). Next, in the above-described embodiment, since the work of manually adjusting the interval between the pair of discharge rollers and putting it in the open state is complicated, the adjustment and opening means using the solenoid or the like is operated by a key on an operation panel (not shown). It is convenient if it is configured so that the operation is started and released by an operation. In this case, a "paper ejection roller post-elimination mode" key is provided on the operation panel, and the program of the control unit is set so that the above operation can be realized by operating the key.

FIGS. 8 (a) and 8 (b) are flow charts of a main flow showing a control procedure having the above-mentioned sheet discharge roller trace elimination mode and a subroutine flowchart showing the control procedure of the sheet discharge roller trace elimination mode. When the copy start button is turned on when the trace elimination mode is selected, the discharge roller interval adjusting solenoid 17, the guide plate lowering solenoid 40, the fans 31 and 35, and the conveyor belt 30 are turned on sequentially or simultaneously to discharge the sheet. Is executed (steps S1 to S
4). When the paper discharge sensor is turned on in step 5, it means that the recording paper is properly discharged onto the paper discharge tray.

Next, FIG. 9 shows an example in which the sorter 46 is arranged at the paper discharge port of the image forming apparatus main body 45, and the introduction rollers 47 and 48 are arranged inside the introduction port of the sorter 46.
In this case, the pair of discharge rollers 13 and 1 on the image forming apparatus main body side
4 and the sorter-side introduction roller pair 47, 48 are arranged in close proximity to each other, and therefore, even when the paper discharge roller pair loses the conveying force, the leading edge of the recording paper 4 has the introduction roller pair 4
When the recording paper reaches the nip portions 7 and 48, the recording paper is given a carrying force and is carried into the sorter. However, in this case, it is necessary that the distance between the nip portion of the rollers 2 and 3 and the nip portion of the introduction roller pair 47 and 48 that constitute the fixing device 1 be shorter than the length of the recording paper in the conveyance direction. For example, when transporting A4 size recording paper in the lateral direction, the distance needs to be 200 mm or less.
With this structure, it is possible to prevent the discharge roller pair from being always opened and the discharge roller trace being formed.

By the way, when the roller interval is opened in order to eliminate the traces of the discharge rollers, if the discharge rollers that have lost the conveying force are projected on the sheet passing surface of the guide plate, the conveyance is disturbed and a jam occurs. Since the fear is increased, it is necessary to cover the roller pair with the guide plate. FIGS. 10 (a) and 10 (b) show an embodiment for realizing such an object, and a holder 16 supported separately from the upper paper ejection guide plate 11 so as to be vertically movable.
The upper solenoid 1 (which supports the upper discharge roller 13)
7a retracts the upper guide plate 11 to a position higher than the lower surface thereof, and the lower discharge guide plate 12 is moved to the lower solenoid 17b.
Thus, the lower paper discharge roller 14 is retracted from the paper-passing surface by rotating upward.

Next, the driven paper discharge roller 13 is supported by a holder 16 made of a leaf spring, and is pressed against the outer peripheral surface of the drive paper discharge roller 14. By this, the pressing force is secured and the carrying force is obtained. However, when the driven-side paper discharge roller 13 is separated from the drive-side paper discharge roller 14, the driven-side paper discharge roller 13 uses the restoring force of the leaf spring. Easily protrudes to the paper surface side (see Fig. 11 (b)). As a result,
Jam is likely to occur. In order to solve this problem, in the embodiment shown in FIG. 11 (a), the upper and lower guide plates 11, 1
A guide rib is provided so as to be rotatable with respect to 2, and the conveyance path of the recording paper is limited by this guide rib so that the recording paper is not interfered with by the ejecting roller that is in a protruding state.

That is, reference numerals 50 and 51 in FIG.
Is a guide rib having a substantially triangular front shape, and is supported rotatably in the vertical direction by the appropriate positions of the guide plates 11 and 12. Angles θ1 and θ are provided by a solenoid (not shown).
It is configured to rotate within the range of 2. Further, it goes without saying that the guide ribs have a predetermined width (width enough to guide the recording paper) in the direction orthogonal to the paper surface. The position of the ribs shown by the solid line is the proper position when the paper discharge rollers have lost the conveying force, and the tip of both ribs is oriented toward the paper passing gap formed between the paper discharge roller pairs that are open. Therefore, the recording paper can be discharged onto the paper discharge tray while being smoothly guided by the ribs without being interfered by the paper discharge roller.

[0018]

As described above, according to one embodiment of the present invention, the distance between the rollers forming the discharge roller pair can be adjusted manually or automatically. It is possible to prevent the formation of a streak-like defective image due to the giving of the waist by the pair of discharge rollers by increasing the roller interval. Further, according to another embodiment, when the conveying force is lost by opening the sheet discharging rollers, the recording sheet is discharged by the cooperation of the suction belt and the conveying belt located in front of the pair of discharging rollers. Since the paper can be delivered to the tray, it is not necessary for the user to put his / her hand in the machine to perform jam processing. Further, since the discharge roller can be easily opened at the time of discharging thick paper by a key operation from the operation panel, operability can be improved. When the sorter is connected immediately after the paper discharge roller pair, the paper discharge roller pair can always be opened, so that an image without the paper discharge roller can be obtained. Further, since the paper discharge roller can be hidden behind the guide plate, it is possible to prevent the occurrence of a jam or the like due to the paper discharge roller protruding on the paper passing surface. Further, instead of concealing the paper discharge roller, if the paper passing range is regulated by the guide ribs so that the paper can directly enter the gap between the transport rollers, jamming can be prevented.

[Brief description of drawings]

FIG. 1A and FIG. 1B are a front view and a side view showing a main part configuration of an embodiment of the present invention.

FIG. 2 is a front view showing the operation of FIG.

FIG. 3 is a schematic diagram showing a modification of the embodiment of FIG.

FIG. 4 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 5 is a schematic configuration explanatory view of another embodiment of the present invention.

FIG. 6 is a specific configuration explanatory diagram of the embodiment of FIG.

FIG. 7 is a specific configuration explanatory view of the embodiment of FIG.

8A and 8B are flowcharts showing an example of control for operating the paper discharge mechanism by an operation from the operation panel.

FIG. 9 is a diagram showing another embodiment of the present invention, showing a configuration example in which a sorter is arranged at the sheet discharge port of the copying machine main body.

10 (a) and (b) are other embodiments of the present invention,
FIG. 3 is a diagram showing a configuration example in which a sorter is arranged at a sheet discharge port of a copying machine main body.

11 (a) and 11 (b) are a structural explanatory view and a partial structural explanatory view of another embodiment of the present invention.

[Explanation of symbols]

1 fixing device, 2 fixing roller, 3 pressure roller, 10
Paper ejection mechanism, 11 Upper paper ejection guide plate, 12 Lower paper ejection guide plate, 13 Upper paper ejection roller, 14 Lower paper ejection roller, 15
Branch, 16 holder, 17 solenoid, 18 spring, 19 paper ejection tray, 20 paper ejection cover, 21 separation claw, 25 cam, 30 conveyor belt, 31 suction fan,
33 ventilation pipe, 34 tube body, 35 fan body, 4
0 solenoid, 45 image forming apparatus main body, 46 sorter, 47, 48 introducing roller, 50, 51 guide rib,

Claims (7)

[Claims] 1. An image forming apparatus having a pair of upper and lower discharge rollers at a discharge port, wherein one discharge roller is moved in the vertical direction so that the distance between the discharge rollers can be adjusted. The structure of the recording paper ejecting section characterized by. 2. An image forming apparatus comprising a pair of upper and lower paper discharge rollers at a paper discharge port, and a fixing device upstream of the paper discharge roller pair, wherein the fixing device and the paper discharge roller pair are provided. Recording means characterized in that upper and lower paper ejection guide plates are arranged with the paper ejection path sandwiched therebetween, and means for adsorbing the recording paper to one of the upper and lower paper ejection guide plates and a conveyor belt are provided. Structure of the paper ejection unit. 3. A means for adsorbing the recording paper and a controller for activating the conveying belt only when the conveying force of the pair of discharge rollers is below a predetermined value.
Alternatively, the structure of the recording paper discharge unit described in 2. 4. The image forming apparatus has a discharge roller trace elimination mode, and when the discharge roller trace elimination mode key on the operation panel is turned on, the control unit shifts to the discharge roller trace elimination mode. 4. The structure of the recording paper discharge section according to claim 1, 2 or 3, wherein the distance between the discharge rollers is widened. 5. The structure of the recording paper discharging section according to claim 1, wherein when a sorter is connected to the paper discharging port, the paper discharging roller pair is always opened. 6. An image forming apparatus including a pair of upper and lower paper discharge rollers at a paper discharge port and a fixing device upstream of the paper discharge roller pair, wherein an image forming apparatus is provided between the fixing device and the paper discharge roller pair. Place the upper and lower paper ejection guide plates with the paper ejection path in between,
A structure of a recording paper discharge section, characterized in that each discharge roller is concealed by the discharge guide plate when the discharge roller pair is completely opened. 7. An image forming apparatus having a pair of upper and lower paper discharge rollers at a paper discharge port and a fixing device upstream of the paper discharge roller pair, wherein the image forming apparatus is provided between the fixing device and the paper discharge roller pair. Place the upper and lower paper ejection guide plates with the paper ejection path in between,
A structure of a recording paper discharge section, comprising guide ribs for guiding the recording paper to a gap between the discharge roller pair when the discharge roller pair is completely opened.