JPH0558527A - Sheet discharging device - Google Patents

Abstract

PURPOSE:To prevent jamming and defective stacking of sheets to be discharged. CONSTITUTION:Roller holders 17 arranged at each end of a positioning part with a roller fitting plate 18 are positioned by fitting circular bosses 17a to round holes 18a, and roller holders 17 arranged at two positions in the center part are positioned by inserting the circular bosses 17a into slightly larger square holes 18b leaving clearances. The roller holders 17 at two positions in the center part are held in a stable condition by pressing pressure-applying roller sets 16 against discharging rollers 15 by the force of pressing member 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet discharging device applied to recording devices such as laser beam printers and facsimiles.

[0002]

2. Description of the Related Art A sheet discharging device applied to a recording device such as a laser beam printer or a facsimile will be described with reference to the drawings. In FIG. 5, the recording sheet 50 after recording is conveyed to the discharge portion by the fixing roller 51 and the pressure roller 52. The sheet discharging unit is provided with a pair of rollers 54 that press against the discharging roller 53 in order to correct the curl of the recording sheet 50 due to the curvature of the conveying path. The roller pair 54 is rotatably supported by a roller holder 55, and the roller holder 55 is rotatably attached to a roller mounting plate 56 having a rotation center 56a.

Below the roller holder 55 is a roller pair 54.
A pressing member 57 for pressing the sheet against the discharge roller 53 is provided. Further, between the fixing roller 51 and the pressure roller 52 and the discharge roller 53 and the roller pair 54, guide members 58a and 58b for guiding the recording sheet 50 are vertically provided.

The roller mounting plate 56, the pressing member 57, and the lower guide member 58b are fastened to the discharge cover 60 by screws 59 (hereinafter referred to as "discharge cover unit"), and these are operated by operating the handle 60a. It can be opened and closed integrally around the fulcrum 60b. The discharge cover unit, the roller pair 54 is pressed by the pressing member 57,
The positioning is performed in the closed state. That is, when the discharge cover 60 is closed, the roller pair 54 presses the discharge roller 53, whereby the entire discharge cover unit is locked. The roller pair 54 and the roller holder 55 are provided in four sets in the width direction so as to correspond to the discharge roller 53 so as to correspond to the size of the recording sheet 50.

In the sheet discharging apparatus shown in FIG. 9, the pair of rollers 54 are rotatably supported by a lower guide member 58b, and the lower guide member 58b is screwed with a discharging cover 60. It is fixed to. A hook 60c is rotatably attached to the discharge cover 60, and is positioned by engaging with a hook 61 on the apparatus body side. Therefore, by operating the handle 60a of the discharge cover 60, the engagement between the hook 60c and the hook 61 is released, and the lower guide member 58b, the roller pair 54, and the discharge cover 60 are integrated into the fulcrum 60b. It is configured to rotate and open.

A fulcrum 60 which is the center of rotation of the discharge cover 60
Since b has a play between the discharge cover 60,
When the discharge cover 60 is opened, the roller pair 54 does not hit the discharge roller 53 and the roller pair 54 escapes.

[0007]

However, in the structure of the apparatus shown in FIG. 5, the roller mounting plate 56 is provided at four places due to the warp and the variation of the processing size and the variation of the size of the roller holder 55. The position of the roller pair 54 varies, and as shown in FIG.
Is a one-sided state. Further, in the configuration of the device shown in FIG. 9, if the position of the discharge cover 60 is slightly varied due to the engagement accuracy of the hooks 60c and the hooks 61, as shown in FIG. There is a possibility that the position may be displaced and a one-sided contact may occur.

In particular, a halogen heater in the fixing roller 51
Heat from 62 causes lower guide member 58b and roller mounting plate
Since 56 is warped and the position of the roller pair 54 is changed, for example, the two central parts of the four parts are in a one-sided contact state. For example, as shown in FIGS. 7 and 10, when the roller 54 on the upstream side in the sheet conveying direction (the left side in FIGS. 7 and 10) has a partial contact, the trailing edge of the roller 54 is discharged when the recording sheet 50 is discharged. Since it is not rotating, it cannot be pushed out, the trailing edge of the recording sheet 50 remains without being ejected, and when the next recording sheet 50 is ejected, the recording sheet 50 slips under the previously ejected recording sheet 50. , The page order might be out of order, or it might fall from the discharge tray 63.
On the contrary, as shown in FIGS. 8 and 11, when the roller 54 on the downstream side in the sheet conveying direction (the right side of FIGS. 8 and 11) is partially biased, the roller 54 rotates at the entrance of the discharge roller 53. Since this is not done, the leading edge of the recording sheet 50 may not be conveyed and may cause a jam (paper jam).

A halogen heater 62 in the fixing roller 51
The heat from the upper guide member 58a may cause thermal deformation or warpage due to a difference in thermal expansion due to a temperature difference between the guide surface side and the back surface side. In this case, as shown in FIG. 12, the guide position is changed so that the recording sheet 50 is discharged from the discharge roller 53 and the roller member.
There was a risk that it could not be guided to the nip with 54 and could cause a jam.

Further, the curl straightening function, which is an original function of the roller pair 54, cannot curl the recording sheet 50 with a certain curvature, so that the curl removal is insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the prior art and to provide a sheet discharging device which prevents jamming of the discharged sheet material and defective stacking.

[0012]

A typical means for solving the above-mentioned problems of the prior art and applied to the embodiments described below is a discharging member for discharging a sheet material and a pressing member for pressing the discharging member. Auxiliary discharge member that interlocks with each other, a support member that supports the auxiliary discharge member so as to be able to press, an attachment member for positioning and attaching the support member to the discharge guide member, the support member, the discharge guide member, and the attachment A discharge cover in which a member is integrally attached and which is openable and closable, and the support member is rotatable with respect to the attachment member;
It is characterized by being attached by positioning with a gap formed.

[0013]

According to the above construction, the supporting member for supporting the auxiliary discharge member in a pressable manner is mounted by pivotally positioning with respect to the mounting member and by positioning with a gap therebetween. Even if warp deformation occurs due to dimensional variation, heat, etc., it is possible to support the auxiliary discharge member at an appropriate position without being affected by the change due to the gap formed with the support member. It will be possible.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet discharging device to which the present invention is applied will be described below with reference to the drawings. In this embodiment, a case where the sheet discharging device is applied to a laser beam printer will be described. 1 is a cross-sectional view showing a schematic configuration of a recording apparatus having a sheet discharging device, FIG. 2 is an explanatory view of the sheet discharging device when a mounting member is warped, and FIG. 3 is a perspective view including a discharging guide member of the sheet discharging device. FIG.

In FIG. 1, reference numeral 1 is a recording sheet, which is a sheet material, and is stored in a cassette 2 or stacked on a manual feed tray 3. The recording sheets 1 are separated and fed one by one from the uppermost one by a feeding roller 4 from a cassette 2. The recording sheets 1 stacked on the manual feed tray 3 are separated and fed one by one by a feeding roller 5 and a separation pad 6 provided opposite to the feeding roller 5. Reference numeral 3a is an extension tray that is used when the recording sheet 1 is long.

Reference numeral 7 denotes a photosensitive drum which is an image carrier,
It is exposed by being irradiated with the laser beam 8 to form an electrostatic latent image. 9 is a developing device with a built-in toner,
Toner is attached to the electrostatic latent image to form a visible image. Reference numeral 10 denotes a transfer roller for transferring the toner image formed on the photosensitive drum 7 to the recording sheet 1. Reference numeral 11 is a fixing roller for fixing the toner image on the recording sheet 1 after transfer by heat of the heater 11a, and 12 is a pressure roller for pressing the fixing roller 11 to apply pressure when fixing the toner.

Denoted at 13 and 14 are discharge guide members for guiding the recording sheet 1 after image fixing to the sheet discharge device. Reference numeral 15 is a discharge roller which is a discharge member for discharging the recording sheet 1. Reference numeral 16 is a pressure roller pair which is an auxiliary discharge member that is pressed and interlocked with the discharge roller 15. Above pressure roller pair
16 is a discharge roller between the fixing roller 11 and the pressure roller 12.
It also serves to correct the curl due to the curvature of the conveyance path of the recording sheet 1 to 15. The pressure roller pair 16 is rotatably supported by a roller holder 17 which is a supporting member. The roller holder 17 is attached to a roller attachment plate 18 which is an attachment member so as to be rotatable around a boss 19. A pressing member 20 for pressing the pressure roller pair 16 against the discharge roller 15 is provided below the roller holder 17.

The roller holder 17, the lower discharge guide member
14, the roller mounting plate 18, and the pressing member 20 are integrally attached to a discharge cover 22 that can be opened / closed around a boss 21 by a screw 23 (hereinafter, these will be referred to as "discharge cover unit 24"). ). In the discharge cover unit 24, when the discharge cover 22 is closed, the pressure roller pair 16 presses the discharge roller 15 to lock the discharge cover unit 24 as a whole. 25 is the recording sheet 1 after discharge
Is a discharge tray for stacking.

Here, the outline of the recording operation of the laser beam printer configured as described above will be described. When a recording start signal is transmitted, laser light is emitted from the photosensitive drum 7 in accordance with an image pattern output from a scanner unit (not shown). To form an electrostatic latent image, and then visualized as a toner image. The recording sheet 1 is fed from the cassette 2 by the feeding roller 4 in synchronism with this timing, and the toner image is transferred to the recording sheet 1 between the photosensitive drum 7 and the transfer roller 10. Then, when the recording sheet 1 passes between the fixing roller 11 and the pressure roller 12, the toner image is fixed by the heat of the halogen heater 11 a and the pressing force of the pressure roller 12. Further, the recording sheet 1 is guided and conveyed by the discharge guide members 13 and 14 and discharged onto the discharge tray 25 by the discharge roller 15 and the roller pair 16.

Next, the structure of the sheet discharging device will be described with reference to FIG. The discharge roller 15, the pair of rollers 16, and the roller holder 17 are provided in four sets in the width direction so as to correspond to the size of the recording sheet 1. Each roller holder above
17 is a circular boss 17a and a round hole 18a for those positioned at two positions at both ends in the positioning portion with the roller mounting plate 18.
Positioning is carried out by fitting with, and those positioned at two central portions are positioned by inserting the circular boss 17a into the slightly larger square hole 18b.

According to the above construction, the ejection cover unit 24 is fitted by fitting the circular bosses 17a of the roller holders 17 arranged at the two ends of the roller mounting plate 18 into the round holes 18a.
Then, the circular bosses 17a of the roller holders 17 arranged at the two central portions can be inserted and mounted in the square holes 18b with a gap. In this case, the positioning of the roller holders 17 arranged at the two central portions is performed by pressing the pair of pressure rollers 16 by the pressing force of the pressing member 20 to the discharge roller 15
It is performed by pressing. As a result, even if the roller mounting plate 18 is warped or deformed, the roller holder 17 at the center portion
The pressure roller pair 16 can be pressed against the discharge roller 15 at an appropriate position by the pressing force of the pressing member 20 without being affected by the gap provided between the roller and the roller mounting plate 18. Therefore, it is possible to prevent the pressure roller pair 16 from hitting the discharge roller 15 one-sidedly, and prevent stack defects and jams.

Further, as shown in FIG. 1, the pressure roller pair 16 is rotatably supported by a roller holder 17, and the roller holder 17 is integrated with the pressure roller pair 16 and is a roller mounting plate 18. It can be rotated around the boss 19. Further, the roller mounting plate 18 is fastened to the discharge cover 22 by a screw 23 in a form in which the lower discharge guide member 14 is overlapped from above, and the pressing member 20 for pressing the roller holder 17 is also screw 23.
It is fastened to the discharge cover 22 by. Further, the discharge cover 22 can be opened and closed centering around the boss 21.
Further, in the discharge cover unit 24, when the discharge cover 22 is closed, the pressure roller pair 16 presses the discharge roller 15 to lock the entire discharge cover unit 24, and the grip 22a is pulled to discharge the discharge cover unit 24. By opening the cover 22, the discharge cover unit 24 is integrally opened.

With the above construction, the positioning of the discharge cover 22 is performed at two points, that is, the boss 21 which is the center of rotation and the contact point between the discharge roller 15 and the pressure roller pair 16. Therefore, since the discharge roller 15 and the pressure roller pair 16 are always in contact with each other and positioned, it is possible to prevent uneven contact of the pressure roller when the recording sheet 1 is discharged.

As shown in FIG. 3, the upper discharge guide member 13 is positioned on the frame 26 of the fixing device by bosses 27 and 28 and fixed by screws 29. The tip 13a of the upper discharge guide member 13 has a rotating shaft 15 of the discharge roller 15.
It is in contact with a.

In this case, the heat of the halogen heater 11a is accumulated, so that the sheet passing surface side of the upper discharge guide member 13 expands and warps in the arrow direction (downward in the drawing). However, as described above, since the tip portion 13a of the upper discharge guide member 13 is in contact with the rotating shaft 15a of the discharge roller 15, the warp is corrected, and the upper discharge guide member 13 and the discharge roller 15 are corrected.
It is possible to prevent the occurrence of a jam when the recording sheet 1 is ejected, since the positional relationship between and does not change.

In the above embodiment, the leaf spring is used as the pressing means of the roller holder 17, but a coil spring or the like can be used, and the mounting location is not limited to the discharge cover 22, and the roller mounting is not limited. Plate 18 and lower discharge guide member 14
And so on. Further, the number of rotations of the roller holder 17 with respect to the roller mounting plate 18 is not limited to two places arranged at both ends, but may be arranged at the center or at two places. However, the number of pressure rollers may be one or three or more, as long as the pressure roller pair 16 can be properly positioned according to the degree of warp deformation. When the roller holder 17 is mounted on the roller mounting plate 18, the circular boss 17a and the square hole 18b are attached.
Although a gap is formed between them, it is desirable to form a gap between the circular boss 17a and the round hole 18a when the warp amount of the roller mounting plate 18 is large.

The upper discharge guide member 13 is a discharge roller.
The tip portion 13a was merely brought into contact with the rotating shaft 15a of the shaft 15. However, for example, when a warp occurs in the opposite direction or when the warp direction is constant in a city, as shown in FIG. It is also possible to form a U-shaped cut groove 13b in the tip portion 13a of 13 and fit the rotary shaft 15a for positioning. In this case, the relative accuracy between the discharge guide member 13 and the discharge roller 15 can be maintained regardless of the warp direction of the upper discharge guide member 13.

The tip portion 13 of the upper discharge guide member 13
Although a and the rotating shaft 15a are in contact with each other, a slight gap may be provided between them. In this case, rubbing noise between the discharge roller 15 and the guide member 13 can be reduced or eliminated. The size of the above gap is the diameter φ of the discharge roller 15.
3 mm or less is desirable for about 16 mm. Alternatively, a highly slidable member such as acetal resin (POM) may be interposed between the upper discharge guide member 13 and the discharge roller 15.

Further, in FIG. 3, the tip portion 13a of the upper discharge guide member 13 is in contact with the discharge roller 15 at five points.
The present invention is not limited to this, and at least 3 points or more are desirable to evenly correct the whole. Further, although the present embodiment has been described with respect to the case where a laser beam printer is applied as a recording device, the present invention is not limited to this, and may be, for example, a copying machine or the like.

[0029]

As described above, according to the present invention, the supporting member for supporting the auxiliary discharging member in a pressable manner is mounted by pivoting the mounting member and positioning with a gap. Even if the mounting member is warped and deformed due to dimensional variation, heat, etc., the gap formed between the mounting member and the supporting member does not absorb the change and is not affected, and the auxiliary discharge member is placed at a proper position. It becomes possible to support. Therefore, it is possible to prevent the stacking failure of the sheet material and the occurrence of the jam and to perform the stable discharging operation. The positioning of the discharge cover is performed by the pressing force of the auxiliary discharge member that presses the discharge member, so that the roller pair forming the auxiliary discharge member is prevented from being unevenly contacted with the discharge member to prevent a jam at the time of discharging the sheet material. It can be prevented. Further, since the mounting position of the discharge guide member is determined by using the rotation shaft of the discharge member, it is possible to prevent the discharge guide member from being warped or deformed due to heat, and to prevent jam when discharging the sheet material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a recording apparatus having a sheet discharge device.

FIG. 2 is an explanatory diagram of a sheet discharging device when a mounting member is warped.

FIG. 3 is a perspective explanatory view including a discharge guide member of the sheet discharging device.

FIG. 4 is an explanatory diagram showing another configuration of the sheet ejection device.

FIG. 5 is a cross-sectional view of a conventional sheet ejection device.

FIG. 6 is an explanatory diagram of a case where a mounting member is warped.

FIG. 7 is an explanatory diagram when a stack defect of sheet materials occurs.

FIG. 8 is an explanatory diagram when a jam occurs in the sheet material.

FIG. 9 is a cross-sectional view of a conventional sheet ejection device.

FIG. 10 is an explanatory diagram when a stacking defect of sheet materials occurs.

FIG. 11 is an explanatory diagram when a jam occurs in a sheet material.

FIG. 12 is an explanatory diagram when a jam occurs due to deformation of the discharge guide member.

[Explanation of symbols]

1 is a recording sheet, 2 is a cassette, 3 is a manual feed tray, 3
a is an extension tray, 4 and 5 are feed rollers, 6 is a separation pad, 7 is a photosensitive drum, 8 is a laser beam, 9 is a developing device, and 10
Is a transfer roller, 11 is a fixing roller, 11a is a heater, 12 is a pressure roller, 13 and 14 are discharge guide members, 13a is a tip portion,
13b is a cut groove, 15 is a discharge roller, 15a is a rotating shaft, 16 is a pressure roller pair, 17 is a roller holder, 17a is a circular boss, 18 is a roller mounting plate, 18a is a round hole, 18b is a square hole, 19, 21, 27 and 28 are bosses, 20 is a pressing member, 22 is a discharge cover, 22a is a handle, 23,
29 is a screw, 24 is a discharge cover unit, 25 is a discharge tray,
26 is a frame.

Claims (3)

[Claims] 1. A discharge member for discharging a sheet material, an auxiliary discharge member that presses the discharge member to interlock, a support member that pressably supports the auxiliary discharge member, and a discharge guide for the support member. And a support member, a discharge guide member, and an openable / closable discharge cover integrally mounted with the mounting member, wherein the support member rotates with respect to the mounting member. A sheet discharging device characterized by being mounted by movable positioning and positioning with a gap. 2. The sheet ejection apparatus according to claim 1, wherein the ejection cover is positioned by a pressing force with which the auxiliary ejection member presses the ejection member. 3. A discharge member for discharging a sheet material, and a discharge guide member for guiding the sheet material to the discharge member, wherein a mounting position of the discharge guide member is a rotation shaft of the discharge member. A sheet ejection device characterized by the above.