JPH0459557A - Sheet discharging device - Google Patents

Abstract

PURPOSE:To realize sheet loading by constituting in such a way that a sheet can be moved sideways while carrying it by means of a pair of carrier rollers and the sheet can be discharged after having offset without moving it slantingly or without leaving wrinkles on it. CONSTITUTION:A sheet P is carried by means of a pair of feed rollers 6, and when the tip of the sheet P is held between a pair of discharging rollers 7, a pair of discharging rollers 7 are moved in the direction crossing at right angles to the sheet carrying direction by sideway moving means 16 and 17 so that the sheet P can be discharged after having been offset. In this, case, when the sheet P is moved sideways in response to sideway movements of the pair of discharging rollers 7, a pair of carrier rollers 6 move the sheet P sideways while carrying the sheet P. Furthermore, when the sheet P moves sideways by means of a pair of discharging rollers 7, the rear edge of the sheet P is carried while being put in turning motion with the pair of carrier rollers 6 having strong holding power as its center.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a sheet discharging device that discharges sheets, and more specifically, the present invention relates to a sheet discharging device for discharging sheets. The present invention relates to a sheet discharging device.

(■) Conventional technology Conventionally, sheet ejection mechanisms in image forming apparatuses such as copying machines and laser beam printers typically have sheets stacked one after another on a paper ejection tray. This is very inconvenient when the user later needs to sort a plurality of copied sheets one by one.

Therefore, a device such as a sorter was developed to sort each sheet or parts at a time, eliminating this inconvenience. However, devices such as sorters are often separate from the image forming apparatus, and their functions and configurations are complex, resulting in problems such as high cost and large size of the device. Therefore, a device that has a simple mechanism and can easily classify sheets has been adopted, which classifies the sheets by type of copy by offsetting the sheets in a direction perpendicular to the conveying direction. According to such a method, it can be relatively easily integrated into the sheet ejection section of the image forming apparatus, and this has a great effect on the installation space and cost of the apparatus, increasing the added value of the image forming apparatus. , used in many devices.

(c) Problems to be Solved by the Invention However, the sheet on which an image has been formed in the image forming section is conveyed to the discharge section by a pair of conveyance rollers, and the leading edge of the sheet is held between the pair of discharge rollers, and the sheet is placed at an appropriate timing after a little advance. The discharge roller pair starts moving in a direction perpendicular to the sheet conveyance direction. At this time, since the rear end of the sheet is held between the pair of conveyance rollers to ensure reliable conveyance, the sheet ends up being twisted between the pair of discharge rollers and the pair of conveyance rollers. In this way, to be twisted and transported, the
This may cause the problem of wrinkles appearing on the skin.

Further, if the sheet is thick, a large moving force is required for the pair of ejection rollers in order to offset the sheet, which poses a problem of increasing the load on the image forming apparatus.

Furthermore, since the sheets are conveyed while twisting, the sheets are ejected in a skewed manner, resulting in problems such as poor alignment of the stacked sheets.

Therefore, the present invention provides a sheet discharging device that enables sheet offset by configuring a pair of conveying rollers so that when the pair of discharging rollers moves laterally, the pair of conveying rollers moves the sheet laterally instead of conveying the sheet. The purpose is to provide the following.

(:) Means for Solving the Problems The present invention has been made in view of the above circumstances, and includes:
For example, this is illustrated with reference to FIGS. 2, 3, and 4(a).

It has a pair of discharge rollers (7) that discharges the sheet (P) out of the apparatus, and a pair of conveyance rollers (6) located upstream of the pair of discharge rollers (7) in the sheet conveyance direction, and the pair of discharge rollers (7) includes a lateral movement means (16, 17) that is movable in a direction substantially perpendicular to the sheet conveyance direction; When the ejection roller pair (7) is laterally moved by the lateral moving means (16, 17) while being held and conveyed by the conveyance roller pair (6), the conveyance roller pair (6) It is characterized in that it is configured to move the sheet (P) laterally without conveying it.

Further, the conveying roller pair (6) is composed of a driving roller (6a) and a driven roller (6b) facing the driving roller (6a), and the pressing force of the driven roller (6b) against the driving roller (6a) is The seat (P) is set to be movable in the lateral direction.

Further, the conveying roller pair (6) or a plurality of drive rollers (6) may be used.
a) and driven spherical rollers (25
), and is characterized in that the pressure contact force of one driven spherical roller (25b) is set larger than the pressure contact force of the other driven spherical rollers (25a, 25c).

(N) Function Based on the above structure, the sheet (P) is conveyed by a pair of conveying rollers (6
), the tip of the sheet (P) is conveyed by the pair of ejection rollers (7).
), the pair of ejection rollers (7) are moved by the lateral movement means (16, 17) in a direction substantially perpendicular to the sheet conveyance direction to offset and eject the sheet (P). At this time, when the sheet (P) is moved laterally in response to the lateral movement of the pair of discharge rollers (7), the pair of transport rollers (6)
moves the sheet (P) laterally while conveying the sheet (P).

Also, when the sheet (P) is laterally moved by the pair of discharge rollers (7), the rear end of the sheet (P) is It is transported while rotating.

Note that the symbols in parentheses are illustrative and do not limit equivalent configurations.

(f) Example The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an image forming apparatus main body 1. As shown in FIG. In the figure, a sheet P is fed from a cassette 2 installed on the right side of the main body 1, and an image formed by an image forming section 3 is transferred to a transfer section 4.
The image is transferred to the sheet P by the fixing unit 5, and then the image is fixed on the sheet P by the fixing unit 5. The sheet is further conveyed upward by the pair of conveying rollers 6, and the image is formed on the sheet stacking unit 8 by the pair of discharge rollers 7. P is discharged. Note that 9 is an optical system that emits a light beam that forms an electrostatic power source on the photosensitive tram 3a of the image forming section 3.

Next, the sheet discharge device 10 including the conveying roller pair 6 and the discharge roller pair 7 will be explained in detail with reference to FIG.

A guide plate 11 from the fixing unit 5 to the pair of transport rollers 6, and guide plates 12 and 13 curved inwardly between the pair of transport rollers 6 and the pair of paper discharge rollers 7 are provided.
A guide plate 14 facing the is provided.

Further, in FIG. 2, a horizontal rail 15 is provided facing in the front-rear direction, and a plurality of rollers 16 are provided that roll in a direction parallel to this rail 15, and a stay 17 that rotatably supports the rollers 16 is provided. A pair of ejection rollers 7 and upper and lower guides 18a and 18b on the upstream side of the pair of rollers 7 are attached to this stay 17, and a detection lever 19 for detecting passage of the sheet P is attached via a pin 19a. It is pivotally supported by this stay 17. In addition, 20
is a sensor, and the lower end of the detection lever 19 turns on this sensor 20 when the sheet P passes.

Further, a drive conveyance roller 6a of the conveyance roller pair 6 is rotatably supported by the main body 1 and connected to a driving means (not shown). A driven conveyance roller 6b fixed to the shaft 21
are opposed to the drive roller 6a and are supported by brackets 22a, 22b via a shaft 21 so as to be able to move toward and away from the drive roller 6a, and this driven roller 6b is supported by springs 23a, 23b.
It is urged to come into pressure contact with the drive roller 6a. Note that the brackets 22a and 22b are attached to the exterior cover 2.
4 is fixed with a small screw or the like (not shown).

Further, when the stay 17 receives a signal to offset the sheet P and the sensor 20 detects the sheet P and turns on, the stay 17 is moved in a predetermined direction by a driving means (not shown) and locked. , sensor 2
When 0 is turned off, the lock is released, and a spring (not shown) returns it to its original position (reference position).

Next, the operation of this sheet discharging device 10 will be explained.

When the image forming apparatus is instructed to form an image, sheets P are fed one by one from the cassette 2, an image is formed on the sheet P by the image forming section 3 and the transfer section 4, and an image is formed on the sheet P by the fixing section 5. The image above is fixed.

Thereafter, the sheet P is guided by the guide plate 11, held between the pair of conveying rollers 6, and then guided by the guide plates 12 and 13 to be conveyed.

Then, when an instruction to offset the seat P is given, the seat P rotates the detection lever 19 clockwise and turns on the sensor 20. Upon receiving the signal, a driving means (not shown) moves the stay 17 to the position shown in FIG. In Figure 2, move the required amount to the back side. At this time, the roller 16 smoothly rolls on the rail 15, and the discharge roller pair 7, guide plates 18a, 18
b. The detection lever 19 also moves together with the stay 17, and the discharge roller pair 7 moves a predetermined amount to the back side, and the stay 17,
Therefore, the discharge roller pair 7 is locked in that position.

The sheet P is held between the pair of discharge rollers 7, and when the leading edge of the sheet P starts to move toward the back, the trailing edge also begins to shift toward the back after a short delay. As a result, the sheet P completes the offset without being twisted much, and when the sheet P is discharged from the pair of discharge rollers 7, the detection lever 19 rotates counterclockwise to turn off the sensor 20. In response to this signal, the stay 17 is unlocked and pulled back by a spring (not shown), and the discharge roller pair 7 returns to the reference position, waiting for the next sheet P to be conveyed by the conveyance roller pair 6.

Thereafter, by repeating the same operation, the sheets P are stacked at the offset position.

In the above, the spring 23a of the conveyance roller pair 6.

Since the clamping force by 23b is set small, 60
It has been confirmed through experiments that even relatively thin paper of approximately 1.5 g/m2 can be offset without causing wrinkles.

Next, another embodiment will be described with reference to FIG.

In this embodiment, the driven rollers 6b of the pair of transport rollers 6a, 6b are replaced with driven spherical rollers 25, one of which is arranged opposite to the drive roller 6a.

The driven spherical roller 25 is rotatably supported in any direction by a roller holder 26 having a plurality of protrusions 26b provided in a spherical hole 26a. The roller holder 26 is set by an elastic ear piece 26c within the section defined by the protrusion 27a of the driven roller base 27 with a slight play. And this driven roller stand 2
A sheet guide 27b for the spherical roller 25 is provided integrally with the roller 7.

For example, as shown in FIG. 4(a), conveyance driven spherical rollers *25a, 25b, and 25c are arranged, one each facing each of the three conveyance drive rollers 6a. The central roller 25b has a large clamping force, and the other rollers 25
The clamping forces of a and 25c are set small.

In this way, the central transport driven spherical roller 25b has a large clamping force, and the rollers 25a and 25c on both sides have a small clamping force, so that when the discharge roller pair 7 is offset, the sheet P is
The rear end of the sheet P rotates slightly diagonally in the conveying direction around the rollers 25b and is conveyed. In this case as well, the gripping force of the pair of ejection rollers 7 on the sheet P is strong, and the sheet P is conveyed obliquely. There's nothing to do.

Since the rear end of the sheet P rotates a little, the strain caused by twisting the sheet P becomes small, and the sheet P is ejected without wrinkles or skewed as described above. It is stacked on the stacking section 8 with an offset.

In addition, as in the conventional example shown in FIG. 4 (bl), when both the ejection roller a and the conveyance roller have cylindrical rollers and their clamping force is not reduced, as shown in FIG. 4 (c),
When the discharge roller pair a is offset, paper folding occurs, depending on the extent to which the wrinkle C remains in the middle of the sheet +P.

Note that the offset amount of the discharge roller pair 7 in this embodiment may be changed for each loft of the sheet P.
Further, one sheet P, which is a delimiter for each lot of sheets P, may be offset for each delimiter.

Further, in the other embodiments, the clamping force of the central spherical roller 25b is increased, but the clamping force of any one of the other spherical rollers may be increased.

Furthermore, upon receiving a signal that the detection lever 19 or the sensor 2o is cut off, the pair of ejection rollers 7 may be offset by a driving means (not shown) after a short delay. By actuating the lever 19 early, it is possible to reliably prevent the pair of discharge rollers 7 from starting to offset before the sheet P is sandwiched between the pair of discharge rollers 7 based on the signal from the sensor 20.

(g) As described in detail, according to the present invention, when a sheet is being held and conveyed by the pair of discharge rollers and the pair of conveyance rollers, the pair of discharge rollers causes the lateral movement means to move the pair of conveyance rollers laterally. By doing so, the pair of conveying rollers can move the trailing edge of the sheet laterally while conveying it, so the sheet can be offset and ejected without causing the sheet to skew or leaving wrinkles on the sheet. Can be loaded.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of an image forming apparatus embodying the present invention;
FIG. 2 is an enlarged sectional side view of the sheet discharging device, FIG. 3 is a sectional front view of a conveying roller pair of another embodiment, and FIG.
) is a plan view showing the sheet conveyance state, FIG. 4(b)
, (c) is a plan view showing a conventional sheet conveyance state. 6... Conveyance roller pair 6a... Conveyance drive roller,
6b...Conveyance driven roller 7...Ejection roller pair,
10... Sheet discharge device 16.17... Lateral movement means (roller, stay) 25... Driven spherical roller 25a... Left driven spherical roller 25b...
Center spherical roller 25c...Right driven spherical roller P...Seat

Claims (1)

[Claims] 1. A pair of discharge rollers for discharging the sheet out of the apparatus, and a pair of conveyance rollers located upstream of the pair of discharge rollers in the sheet conveyance direction, and the pair of discharge rollers is located upstream of the pair of discharge rollers in the sheet conveyance direction. In a sheet discharging device having a lateral moving means that can move in a direction substantially perpendicular to A sheet discharging device characterized in that, when a pair of rollers is moved laterally, the pair of conveying rollers causes the pair of conveying rollers to move the sheet laterally while conveying the sheet. 2. The conveying roller pair includes a driving roller and a driven roller facing the driving roller, and the pressure contact force of the driven roller with respect to the driving roller is set so that the sheet can be moved in the lateral direction. 1. The sheet discharging device according to 1. 3. The conveyance roller pair is composed of a plurality of drive rollers and driven spherical rollers facing each of the drive rollers, and the pressure contact force of one driven spherical roller is set to be larger than the pressure contact force of the other driven spherical rollers. The sheet discharging device according to claim 1.