JPH054769A - Sheet stacking member - Google Patents

Abstract

PURPOSE:To increase the sheet stacking capacity number of a sheet stacking member and improve its sheet arranging performance. CONSTITUTION:A paper discharging device M formed of a discharge roller 16, a curl removing roller 17, and the like is fitted to a paper discharge frame 22. A stack reference face 22f for positioning the rear edge of a sheet S falling slidingly after being discharged from the paper discharging device M is formed at the paper discharge frame 22. In the paper discharge frame 22, the stack reference face 22f and a member for supporting the paper discharging device M are formed of the same member, and the position accuracy of the stack reference face 22f in relation to the paper discharging device M can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking member for stacking sheets discharged from a sheet discharge device of an image forming apparatus such as a printer or a copying machine, and more particularly to a sheet stacking member for positioning discharged sheets. Concerning the structure of.

[0002]

2. Description of the Related Art A discharge tray 18 as a sheet stacking member
FIG. 7 shows an example in which the printer is attached to the printer. The printer of this example is a transfer type / heat roller fixing type laser printer using an electrophotographic process. Reference numeral 1 is a printer main body, and 2 is a rotating drum type electrophotographic photosensitive member, which is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). Primary charging processing, image information scanning exposure L by laser scanner 4
(4a is a laser reflection mirror) and a developing device 5 performs a developing process to form a toner image corresponding to the target image information on the peripheral surface of the photoconductor 2.

On the other hand, from the inside of the paper feed cassette 9 to the paper feed roller 1
0 and a separating member such as a separating claw (not shown) separates and feeds one sheet of recording paper (sheet) S, and the registration roller pair 1
1 is supplied to the pressure contact nip portion (transfer portion) n between the photosensitive member 2 and the transfer roller 6 in synchronism with the rotation of the photosensitive member 2, so that the toner image on the photosensitive member 2 side is sequentially transferred to the sheet S. Go

The sheet S passing through the transfer portion n is separated from the photoconductor 2 and is introduced into the fixing device 12, where the toner image is fixed. After the transfer of the toner image, the photoconductor 2 is cleaned by a cleaning device 7 to remove residual toner such as transfer residual toner, and is repeatedly used for image formation.

The fixing device 12 of this example is of a heat roller fixing type, and is composed of an aluminum fixing roller 12a having a halogen heater 12c as a heat source and a rubber pressing member which is pressed against the lower side of the fixing roller. It is composed of a roller 12b. The fixing roller 12a is temperature-controlled to a predetermined fixing temperature, and the toner image surface of the sheet S is introduced into the pressure contact nip portion N between the fixing roller 12a and the pressure roller 12b with the fixing roller 12a side introduced and passed therethrough. The image is fixed on the sheet S as a permanently fixed image by heat and pressure.

The sheet S having passed through the fixing device 12 has a pair of paper discharge rollers 13 and the flapper 1 in the first switching posture shown by the solid line.
4, upper surface side, U-turn sheet path 15, discharge roller 16
The sheet is discharged and stacked on the sheet stacking member (face-down discharge tray) 18 on the upper surface of the printer with the image facing downward (face-down).

Alternatively, the printer is provided on the rear side of the printer opposite to the side of the paper feed cassette 9 so as to be rotatable around a hinge shaft 20, and normally, as shown by the solid line, the paper is folded up and folded to be stored. When the tray (face-up sheet ejection tray) 19 is tilted substantially horizontally as shown by the two-dot chain line to open it, the flapper 14 interlocks with the opening and moves to the second position indicated by the broken line.
The sheet S that has been converted to the switching posture and has passed through the fixing device 12
Is linearly conveyed through a path on the lower surface side of the paper discharge roller pair 13 and the flapper 14, and is discharged and stacked on the paper discharge tray 19 with the image surface facing upward (face up).

By the way, the sheet S introduced into the fixing device 12 after the toner image is transferred at the transfer portion n is fixed to the fixing roller 1.
Since a temperature of 150 to 180 ° C. and a pressure of about 7 kg are applied by passing through the nip portion N between the 2a and the pressure roller 12b, when the sheet S is paper, the sheet S is pressed against the fixing roller 12a. Sheet S by roller 12b
Curl (image surface side is concave) in which the front end and the rear end are each warped upward is likely to occur.

The curl of the sheet S generated by passing through the fixing device 12 is such that the sheet S is the sheet stacking member 1.
When discharged to 8, the curl is further curled by passing through the U-turn sheet path 15 which is curved in the same direction as the curl direction. Therefore, the curl removing rollers 17 and 17 are arranged on the lower surface side of the discharge roller 16 by pressing to discharge the sheet S while applying a bending force in the direction opposite to the curl direction, thereby reducing the curl and onto the sheet stacking member 18. Ejected and loaded.

When the recording paper is discharged to the paper discharge tray 19, the recording paper is discharged to the paper discharge tray 19 while being in contact with the lower surface of the flapper 14 in the second switching posture and being slightly bent in the direction opposite to the curl direction. As a result, the curl is removed, and the curl is discharged and loaded with almost no curl.

By the way, the number of sheets S that can be stacked on the sheet stacking member 18, the alignment, and the like greatly depend on the structure of the sheet stacking member 18 with respect to the positions of the discharge roller 16 and the curl removing roller 17.

FIG. 8 shows an inclined surface 18a as a sheet material stacking member and a stacking reference surface 18 substantially perpendicular to the inclined surface 18a.
The case where the paper discharge tray 18 having b is attached is illustrated. The sheet discharge tray 18 is attached to the apparatus main body with the inclined surface 18a having an appropriate inclination angle θ with respect to the horizontal plane H, and the sheet S discharged in the direction of arrow A by the sheet feeding roller 16 or the like is, for example, the rear edge thereof. On the inclined surface 18a
It drops to a point, slides down in the direction of arrow B, and abuts this trailing edge against the loading reference surface 18b to stop. At this time, when the drop point P at the trailing edge of the sheet S and the stacking reference surface 18b are close to each other as shown by the solid line, the sliding distance D of the sheet S is D.
Since the number of 1 is small, the stackability of the stacked sheets S is good. However, since the stacking reference surface 18b of the discharge tray 18 and the discharge roller 16 are also close to each other, the trailing edge of the sheet S easily rides on the stacking reference surface 18b, and the stackable number of sheets S is significantly reduced.

On the other hand, the drop point P of the sheet S and the discharge tray 1
8 is separated from the stacking reference surface 18b as indicated by a broken line, the trailing edge of the sheet S is hard to ride on the stacking reference surface 18b, so that the number of stackable sheets S is large,
Sliding distance D2 of the sheet material S after falling on the discharge tray 18
Becomes longer, the alignment of the sheets S becomes worse.

As described above, the sheet S conveyed in the printer main body by various rollers is ejected by the paper ejection roller 16
The curl removing roller 17 loosens the sheet S to the outside of the printer body and drops it on the paper discharge tray 18 for sliding. The structure of the sheet discharge tray 18 with respect to the curl removing roller 17 and the position accuracy of the stacking reference surface has a great influence.

[0015]

However, according to the prior art, the paper discharge device M, which generally includes the discharge roller 16 and the curl removing roller 17 as main constituent members, is attached to the frame member constituting the printer main body. The discharge tray 18 is positioned and mounted on the frame member. For this reason, the paper discharge device M and the paper discharge tray 18 are indirectly positioned via the frame member, and it is difficult to increase the positional accuracy of the paper discharge tray 18 with respect to the paper discharge device M. Due to this, there is a problem that it is difficult to increase the number of sheets S stacked on the discharge tray 18 and to improve the alignment.

Therefore, according to the present invention, the stacking reference surface for restricting the position of the sheet discharged from the discharging device is formed in the same discharging frame as that to which the discharging device is attached, and the positional accuracy of the stacking reference surface with respect to the discharging device is improved. It is an object of the present invention to provide a sheet stacking member that can increase the number of sheets that can be stacked and improve the alignment by increasing the height.

[0017]

The present invention has been made in view of the above circumstances. For example, referring to FIG. 1, a sheet discharging device (M) attached to a sheet discharging frame (22) is shown.
In the sheet stacking member that stacks the sheet (S) discharged from the sheet by falling slip, the stacking reference surface (22f) for positioning at least one side edge of the sheet material is provided in the discharge frame (22). ) Is formed.

[0018]

According to the above construction, a member for attaching the discharge roller (16) and the curl removing roller (17) for determining the discharge direction and discharge position of the sheet (S), and the sheet stacking standard for positioning the discharged sheet (S) Since the member forming the surface (22f) is the same paper discharge frame (22), the relative positional relationship between the discharge device (M) and the sheet stacking reference surface (22f) is determined by the precision of these parts. , Accurate and stable.

That is, since the relative positions of the two are determined without interposing other members, for example, even if the position of the discharge tray (27) varies with respect to the discharge frame (22), the discharge device (M) and the sheet stacking unit are stacked. The relative position to the reference plane (22f) is constant. Further, for example, in a printer or the like, heat is applied to the sheet (S) by the fixing process, so that the temperature of the discharged sheet (S) becomes 50 to 70 ° C., and the sheet discharge device (M) and the discharge frame are discharged. (22) causes thermal deformation.
Even in this case, since the sheet stacking reference surface (22f) is integrated with the paper discharge frame (22), the deformation amount is small, and the deformation directions are the same, so that the relative positional deviation can be minimized. ..

The reference numerals in the parentheses are for the purpose of comparing the drawings and do not limit the structure of the present invention.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, and is a cross-sectional view showing a structure near a paper discharge device M and a paper discharge frame 22 of a printer. In the figure, 16 is a discharge roller for face-down discharge of the printer of FIG.
Reference numeral a is a roller shaft, 16b is a plurality of rubber rollers 17, 17 provided on the roller shaft 16a, which are curl removing rollers.

Reference numeral 21 is a roller holder, and 21b and 21b are U grooves, and the curl removing rollers 17 are rotatably held in the U grooves 21b. Reference numeral 21a is a pin provided under the roller holder. Reference numeral 22 is a paper ejection frame, 22a is a stacking portion of the paper ejection frame 22, and 22b is a frame portion.
In the frame portion 22b, 22c is a paper guide rib, 22c
d is a spring seat, and 22e in the stacking portion 22a is a vertical tray rib, and a stacking reference surface 22f for the sheet S is formed on the front surface of the vertical tray rib 22e. Reference numeral 23 denotes a roller spring, one of which is held by a pin 21a of a roller holder 21 and the other of which is held by a spring seat 22d of a paper discharge frame 22.
Is pressed in the direction of the discharge roller shaft 16a. A plurality of curl removing rollers 17, roller holders 21, roller springs 23, and spring seats 22d are provided at positions corresponding to the rubber roller 16b. The roller holder 21 is held by a holder support portion (not shown) of the paper discharge frame 22 so as to be slidable in the direction of arrow C, that is, in the direction of the discharge roller 16, and the curl removing roller 17 is always applied to the discharge roller 16 by the spring force of the roller spring 23. Being pressed. The discharge roller shaft 16a is held by the paper discharge frame 22 via a bearing (not shown). Reference numeral 24 is a paper discharge upper guide for guiding the front end of the sheet S to the paper discharge roller 16, and the paper discharge frame 2 is provided at both ends thereof.
It is fixed at 2. Reference numeral 25 is a top cover of the printer main body, 26 is a back cover, 26a is a paper guide rib, and 27 is a paper discharge tray.

The sheet S on which image formation has been completed in the printer body is conveyed upward along the paper guide ribs 26a of the back cover 26, and then to the curved portion formed by the paper discharge upper guide 24 and the paper guide ribs 22c. The tip is guided to the nip portion between the discharge roller 16 and the curl removing roller 17. Next, the sheet is discharged through the curl removing path formed by the curl removing roller 17, and is stacked on the stacking portion 22 a of the discharge tray 27 and the discharge frame 22.

In this embodiment, the paper discharge frame 22 is
Discharge device M, that is, discharge roller 16 and curl removing roller 1
Since the frame portion 22b that supports 7 and the like and the stacking portion 22a on which the rear end of the sheet S is stacked are integrally configured,
The accuracy of the relative positional relationship of the stacking reference surface 22f with respect to the sheet discharging device M can be easily ensured. Even if the relative positions of the paper discharge frame 22 and the paper discharge tray 27 deviate from each other to some extent, the number of stacked sheets S to be discharged and the alignment thereof are not affected.

Further, since the conveyed sheet S is at a high temperature, the paper discharge frame 22 is thermally expanded or thermally deformed, but since the deviation directions are the same, the paper discharge device M and the stacking reference surface 22.
The relative positional deviation from f can be suppressed to a minimum.

Further, because of the integral structure, it is possible to increase the rigidity of the paper discharge frame 22, and it is easy to provide sufficient strength against external force and thermal deformation.

Further, as shown in FIG. 2, if a stacking tray 30a in which the stacking section 22a of the discharge frame 22 and the discharge tray 27 in FIG. Therefore, it is possible to prevent foreign matter, dust, and sparks due to static electricity from entering the inside of the printer through the gap and causing a malfunction of the printer.

The second embodiment shown in FIGS. 3 and 4 differs from the first embodiment described above in that the paper discharge tray 22 has the discharge roller 1
It is configured such that it can be rotated with respect to the printer main body around the center 6.

FIG. 3 is a schematic view showing the arrangement in the axial direction, and FIG. 4 is a sectional view showing the discharge port portion.

25 is a top cover, 25 is an upper conveyance guide,
32 is a discharge roller, 32a is a discharge roller shaft, 32b is a rubber roller, and 33a and 33b are printer body constituent members.
34a and 34b are discharge roller bearings, and the discharge frame 22.
In addition to supporting the discharge roller 16, it also supports the printer body constituent members 33a and 33b so as to be rotatable. Therefore, the discharge frame 22 can be rotated around the discharge roller 16 with respect to the printer body, and its posture is maintained by a discharge frame holding member (not shown). In FIG. 4, the solid line indicates the usage state P1 and the dotted line indicates the usage state P2.

The usage state P1 is the same as that in the first embodiment. In the usage state P2, the user of the printer discharges the discharge frame 2
The inclination angle θ of 2 with respect to the horizontal plane H is arbitrarily changed. Even if the inclination angle θ is changed, the paper discharge frame 22 and the discharge device M rotate integrally around the discharge roller 16, so that the relative positions of the paper discharge frame 22 and the stacking reference surface 22f with respect to the paper discharge device M are constant. Retained.

When the printer is used in the used state P2, the sheet S conveyed after the image formation is guided to the discharge roller 16 through the curved path, but the curved curvature becomes larger than that in the used state P1. Sheet S curl, especially OH
Curling of thick paper such as P film, postcards, and envelopes can be greatly reduced.

When the printer main body is installed on a side desk or tray lower than the desk rather than on the desk and used, if the printer is set in the usage state P2, the leading end of the sheet S is located above in the stacked state. Therefore, operability is also good.
In FIG. 5, 40 is a printer, 41 is a desk, 42 is a computer, and 43 is a side desk on which a printer is installed.

FIGS. 6A and 6B show the third embodiment. In this embodiment, the face-up paper discharge tray is provided with discharge rollers,
Rolls and the like are integrally provided.

FIG. 6A is a sectional view showing the structure of the fixing device and the face-up sheet discharging portion of the printer.

50 is a fixing device, 50a is a fixing roller, and 5 is a fixing roller.
0b is a pressure roller, and 50c is the fixing roller 5 with the leading edge of the sheet.
0a and a fixing entrance guide introduced into the nip portion of the pressure roller 50b, and 50d is a separation guide for separating the leading end of the sheet from the fixing roller 50a. Reference numeral 51 is a face-up type discharge frame, 51a is a stacking section, and 51b is a frame section. Reference numeral 52 is a face-up discharge roller, 53 is a face-up roller, 54 is a face-up roller spring, which presses the face-up roller 53 against the face-up discharge roller 52 with a predetermined pressure, and 54a serves as a guide for the sheet S. .. Numeral 55 is a flapper which, when in the position indicated by the solid line, ejects the sheet front end face down along a curved path, and when in the position indicated by the dotted line, the sheet tip is guided to the face up ejection roller 52. 56 is a face-up discharge tray, and 57 is a flexible hinge that can be folded when face-up discharge is not performed or when the printer is transported. Member 52 for discharging these
57 is attached to the face-up paper ejection frame 51.

The face-up paper ejection frame 51 is screw 5
It can be easily attached and detached by loosening 8, which may be a user option. If face-up paper ejection is not used, attach a face-up cover 59 that covers the ejection port as shown in FIG. 6 (b). If face-up paper ejection is required, attach the face-up paper ejection frame 51. Just attach it. Since the face-up discharge roller 52 that discharges the sheet S, the face-up discharge roller 53, and the like that are easy to mount are supported by the face-up discharge tray 51 having the stacking reference surface 22f, the positional accuracy is guaranteed, and Even when worn by the user, a predetermined paper discharge capability can be obtained.

[0039]

As described above, according to the present invention, the discharging device for discharging the sheet is supported by the discharging frame having the stacking reference surface for positioning the discharged sheet. Such an effect can be obtained.

(1) Since the relative positional accuracy between the discharging device and the stacking reference plane can be increased, the number of sheets stacked can be increased and the alignment can be improved at the same time.

(2) Further, even if the discharge frame is warped and deformed for manufacturing reasons, or is expanded or deformed by the heat transmitted from the discharged sheet, the positional deviation direction is the same, so that the relative deviation is caused. There is no or minimal hold, and always stable loading capacity and alignment.

(3) When the paper discharge frame and the paper discharge tray are integrally formed, the rigidity can be increased so that sufficient strength can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing another embodiment of the paper discharge frame.

FIG. 3 is a front view showing a second embodiment.

FIG. 4 is a vertical sectional side view of the paper ejection frame.

FIG. 5 is a layout diagram of a printer and the like.

FIG. 6 (a) is a vertical sectional side view showing a third embodiment, and FIG. 6 (b) is a vertical sectional side view showing a state where a cover is also mounted.

FIG. 7 is a vertical side view of a conventional printer.

FIG. 8 is a vertical sectional side view of the paper ejection frame.

[Explanation of symbols]

 22 Paper ejection frame 22f Stacking reference surface M Ejector S sheet

Claims (1)

Claim: What is claimed is: 1. A sheet stacking member for stacking a sheet discharged from a sheet discharge device attached to a sheet discharge frame, wherein at least one side edge of the sheet is positioned. A sheet stacking member, wherein a stacking reference surface is formed on the paper discharge frame.