JPH11255390A - Paper emerging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper emerging device in which sheet misalignment on an emergence tray is achieved by means of deceleration of an emerging roller using a simple configuration without prolonging the conveyance distance or giving a damage to the sheet. SOLUTION: This device is composed of a paper emerging roller 15 to emerge sheets onto an emergence tray 30, a guide member to guide sheets to the emerging roller 15, a driving means 20 to give a driving force to the emerging roller, a drive transmitting means 21 to transmit the drive force of the driving means to the emerging roller, and a detecting/means 17 which is located upstream of the emerging roller 15 about the sheet conveyance direction and detects whether any sheet exists on the guide member. A certain period after the sheet trailing edge has passed the sheet detecting means 17, the drive transmitting means exhausts the fed sheet from the exhaust roller at a speed lower than the normal emerging speed, and it is possible to eliminate out of alignment of the sheets emerged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper discharge device for preventing a sheet from becoming irregular when an image-formed sheet is stacked on a paper discharge tray in an electrophotographic copying machine or a printer.

[0002]

2. Description of the Related Art Recent copying machines are also required to provide a more comfortable use state by increasing the copying speed in order to improve copying performance. Therefore, there is a problem that the sheet conveying speed is further increased, and accordingly, the irregularity of the discharge sheets on the discharge tray is acceleratedly deteriorated.

To solve this problem, Japanese Patent Application Laid-Open No.
The technology disclosed in Japanese Patent No. 3070 is known. According to the technology disclosed in this publication, a corrugated roller, which includes a pair of rollers for gripping a sheet and rotates at a lower speed than the discharge roller, is provided immediately after the discharge roller located at the rearmost downstream portion of the sheet conveyance path. Things.

[0004]

A conventional sheet discharging apparatus is composed of a pair of discharging rollers for transmitting a drive from a driving source and discharging a sheet onto a discharging tray. Therefore, when the copying speed is increased, the sheet discharge speed nipped and conveyed by the discharge roller pair is also proportionally increased, and the sheets discharged to the discharge tray are only increasing in irregularity.
In order to solve this problem, the technique disclosed in the above-described conventional example is provided with a corrugated roller that rotates at a lower speed than the discharge roller immediately after the final discharge roller. After the sheet has passed through, the sheet is discharged at the speed of the corrugating roller rotating at a lower speed, so that the sheet irregularity is improved as compared with the case where the sheet on the sheet discharge tray is discharged at the normal discharge speed. However, the low-speed discharge force of the corrugated roller acts on the sheet as a load, compared to the discharge force of the discharge roller rotating at a normal speed, so that the sheet is distorted between the discharge roller and the corrugated roller. . This distortion appears on the sheet as damage in the form of waving at the pitch between the discharge roller and the corrugated roller. For this reason, the discharged sheets are not only undesirably aesthetically pleasing, but also result in an increased stacking height and a reduction in the stacked sheet discharge capacity. In order to solve this problem, it is conceivable to reduce the pressing force of the corrugated roller pair. However, in such a case, the sheet discharging force is also reduced, which results in uneven paper discharge. Providing such a corrugated roller immediately after the paper discharge roller results in a longer sheet conveyance distance and a longer first copy time which is positioned as a time necessary for copying the first sheet. Will be. The provision of another pair of rollers has a problem that the number of paper jams in the copying machine increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and provides a sheet discharging apparatus which realizes a sheet irregularity on a sheet discharging tray by a method of decelerating a sheet discharging roller with a simple structure without increasing a conveying distance. It is intended to realize without damaging the.

[0006]

In order to solve this problem, a paper discharge device according to the present invention comprises a paper discharge tray for stacking sheets discharged along a conveyance path, and discharging the sheets onto the paper discharge tray. Sheet discharging means, a guide member for guiding the sheet to the sheet discharging means, a driving means for applying a driving force to the sheet discharging means, and a sheet on the guide member upstream of the sheet discharging means. Detecting means for detecting the presence / absence of the sheet, and after a predetermined time elapses after the trailing edge of the sheet has passed the detecting means for detecting the presence / absence of the sheet, the drive means controls the discharge at a lower speed than the discharge speed of the normal sheet. The configuration is such that: A discharge tray for stacking sheets to be discharged along the transport path; a discharge roller for discharging the sheets onto the discharge tray; Driven roller, a guide member for guiding the sheet to the discharge roller, driving means for applying a driving force to the discharge roller, and drive transmission means for transmitting the driving force of the driving means to the discharge roller. Detecting means for detecting the presence or absence of a sheet on the guide member upstream of the discharge roller in the sheet conveying direction, wherein the drive transmission means includes means for detecting the presence or absence of the sheet at the rear end of the sheet. After a lapse of a predetermined time after the passage, the sheet discharged from the discharge roller is discharged at a lower speed than the normal discharge speed. Further, the deceleration means of the drive transmission means includes a first drive train including an electromagnetic clutch means for enabling on / off of drive transmission from a drive source, and a separate drive system for the discharge roller from the electromagnetic drive means. And a second drive train for transmitting drive, wherein the second drive train is provided with a one-way rotation transmission clutch.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a paper discharge tray for stacking sheets discharged along a conveyance path, and a sheet discharge means for discharging the sheets onto the paper discharge tray. A guide member for guiding the sheet to the sheet discharging unit, a driving unit for applying a driving force to the sheet discharging unit, and detecting the presence or absence of a sheet on the guide member upstream of the sheet discharging unit. Detecting means for controlling the drive means to discharge the sheet at a lower speed than a normal sheet discharging speed after a predetermined time has passed after the rear end of the sheet has passed the detecting means for detecting the presence or absence of the sheet. This has the effect of reducing the irregularity of the sheets discharged on the discharge tray.

According to a second aspect of the present invention, there is provided a sheet discharge tray for stacking sheets discharged along a conveyance path,
A discharge roller that enables the sheet to be discharged onto a discharge tray, a driven roller that abuts against the discharge roller to pinch and convey the sheet, and a guide member that guides the sheet to the discharge roller. A driving means for applying a driving force to the discharge roller, a drive transmitting means for transmitting the driving force of the driving means to the discharge roller, and Detection means for detecting the presence or absence of a sheet, the drive transmission means, after a predetermined time has passed after the rear end of the sheet has passed the means for detecting the presence or absence of the sheet, the sheet discharged from the paper discharge roller, The sheet is discharged at a lower speed than the normal discharge speed, and has the effect of reducing the irregularity of the sheets discharged onto the sheet discharge tray in the same manner as described above.

According to a third aspect of the present invention, there is provided the first drive train, wherein the speed reduction means of the drive transmission means includes an electromagnetic clutch means capable of turning on / off a drive transmission from a drive source; A second drive train for transmitting drive to the discharge rollers by a different system from the electromagnetic clutch means, wherein a one-way rotation transmission clutch is disposed in the second drive train. In addition, there is a general-purpose effect that the degree of deceleration of the sheet from the normal discharge speed can be freely determined by the drive transmission configuration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block sectional view of a copying machine provided with a sheet discharging device according to the present invention. The image forming mechanism 3 forms an image by exposure by an exposure optical system 1 and transfers the image to a sheet 2, and A sheet feeding mechanism 4 for feeding the sheet 2 to the image mechanism 3; The image forming mechanism 3 includes a photoconductor drum 5 and a charger 6, a developing device 7, a transfer charger 8, a separation charger 9, a cleaning unit 10, and the like provided around the photoconductor drum 5, and is formed by a known electrophotographic method. A toner image corresponding to a document image to be exposed is formed on the photosensitive drum 5 and the toner image is transferred to the fed sheet 2. In front of the transfer section where the photosensitive drum 5 and the transfer charger 8 face each other, a paper feed path 11 for feeding the sheet 2 received from the paper feed mechanism 4 to the transfer section is provided. Is provided.

The registration roller 12 stops the sheet 2
Is fed, and the skew of the sheet 2 is corrected by the alignment of the leading end, and the timing of feeding the sheet 2 to the transfer unit is adjusted according to the timing of starting the conveyance. Behind the transfer section, a conveying means 13 for conveying the sheet 2 after the transfer of the toner image, the sheet 2 conveyed by the conveying means 13
And a paper discharge roller 15 for discharging the sheet 2 sent from the fixing device 14 are provided. A sheet guide member 16 from the fixing device 14 to the paper discharge roller 15 and a paper discharge sensor lever 17 for detecting the presence or absence of a sheet on the sheet guide member 16 are provided between the fixing device 14 and the paper discharge roller 15. When the sheet 2 passes so as to push up the lever, the photo sensor 18 provided at one end of the sheet discharge sensor lever 17 is turned on / off to detect the passage of the sheet 2.

As shown in FIG. 2, a discharge gear 19 for receiving a driving force is fixed on the shaft of the discharge roller 15, and a gear train 21 for transmitting a drive from a motor 20 serving as a drive source. And a gear train 22 in parallel with the gear train 21
The driving force is given via Gear train 21 for drive transmission
Is constituted by gears 23, 24, 25 and an electromagnetic clutch 26 as shown in FIG. 3, and the electromagnetic clutch 26 can turn on / off the drive transmission to the paper discharge gear 19. The gear train 22 also includes gears 27, 28, and 29, as shown in FIG.
Driving force is applied from the motor 20 via 3.24. One of the gears 28 is provided with a one-way rotation transmission clutch gear that transmits drive in only one direction. When the electromagnetic clutch 26 is off, a gear train via the one-way rotation transmission clutch gear 28 is provided. 2
2, the driving force is transmitted to the paper discharge gear 19.

When the electromagnetic clutch 26 is on,
The driving force is transmitted from both the drive transmission gear train 21 and the gear train 22 to the sheet discharge gear 19, but the one-way rotation transmission clutch gear 28 arranged in the gear train 22 idles on the shaft. Accordingly, the sheet discharge speed of the discharge roller 15 is determined according to the rotation speed determined by the drive transmission gear train 21.

Therefore, by setting the rotation transmission ratio of the gear train 22 to be lower than the rotation transmission ratio of the drive transmission gear train 21, when the electromagnetic clutch 26 is off, the discharge tray of the discharge roller 15 The sheet discharge speed to the sheet 30 can be reduced to an arbitrary discharge speed from the normal sheet conveyance speed. The on / off timing of the electromagnetic clutch 26 can be determined at an arbitrary timing without decreasing the overall sheet conveying speed by taking the timing of the photo sensor 18 from the above-described photo sensor 18. This makes it possible to eliminate irregularities in paper discharge on the paper 30. Means for decelerating only the final discharge roller and only the rear end of the sheet by this method does not increase the length of the sheet conveyance path as in the technique disclosed in the conventional example, and does not cause damage to the sheet.

In the above description, the driving force of the motor is changed via the gear train. However, the present invention can also be realized by controlling the rotation speed of the motor.

No matter how fast the normal sheet conveyance speed is, according to the electromagnetic clutch and the one-way rotation transmission clutch gear structure, there is no need for a circuit-like speed changing means by a drive source motor, so that the cost is low and the control is simple. Can be realized.

[0017]

As described in detail above, the present invention relates to a sheet discharge tray for stacking sheets discharged along a transport path, sheet discharge means for discharging the sheets onto the sheet discharge tray, A guide member for guiding the sheet to the discharging unit, a driving unit for applying a driving force to the sheet discharging unit, and a detecting unit upstream of the sheet discharging unit for detecting the presence or absence of a sheet on the guide member. A predetermined time after the trailing edge of the sheet has passed the detecting means for detecting the presence or absence of the sheet, after the elapse of a predetermined time, the driving means to control the discharge at a lower speed than the discharge speed of the normal sheet, Since the discharge speed of the sheets discharged onto the discharge tray is slowly reduced, the sheets are not rushed and the unevenness can be eliminated. That. A discharge tray for stacking sheets to be discharged along the transport path; a discharge roller for discharging the sheet onto the discharge tray; and Driven roller, a guide member for guiding the sheet to the discharge roller, driving means for applying a driving force to the discharge roller, and drive transmission means for transmitting the driving force of the driving means to the discharge roller. Detecting means for detecting the presence or absence of a sheet on the guide member upstream of the discharge roller in the sheet conveying direction, wherein the drive transmission means includes means for detecting the presence or absence of the sheet at the rear end of the sheet. After a lapse of a predetermined time after passing, the sheet discharged from the discharge roller is discharged at a lower speed than the normal discharge speed. Advantage of being able to eliminate is set is obtained. Further, the speed reduction means of the drive transmission means includes an electromagnetic clutch means for enabling on / off of drive transmission from a drive source.
And a second drive train for transmitting drive to the discharge rollers by a different system from the electromagnetic clutch means, and a one-way rotation transmission clutch is provided in the second drive train. The degree to which the sheet is decelerated from the normal discharge speed can be freely determined by the drive transmission configuration, and it is possible to eliminate irregularities in the discharged sheet by simple control at low cost. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block cross-sectional view of a copying machine having a sheet discharge device of the present invention.

FIG. 2 is a configuration perspective view of a sheet discharge device of the present invention.

FIG. 3 is a perspective view of the configuration of a first drive train of the sheet discharge device of the present invention.

FIG. 4 is a perspective view of a configuration of a second drive train of the sheet discharge device of the present invention.

FIG. 5 is a diagram illustrating a conventional paper ejection device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Exposure optical system 2 Sheet 3 Image forming mechanism 4 Paper feed mechanism 5 Photoconductor drum 6 Charger 7 Developing device 8 Transfer charger 9 Separation charger 10 Cleaning means 11 Paper feed path 12 Registration roller 13 Transport means 14 Fixing device 15 Discharge roller 16 Guide member 17 Discharge sensor lever 18 Photosensor 20 Motor 21 Drive transmission gear train 22 Drive transmission gear train 26 Electromagnetic clutch 28 One-way rotation transmission gear 30 Discharge tray

Claims (3)

[Claims] A sheet discharge tray for stacking sheets discharged along a conveyance path; sheet discharge means for discharging the sheets onto the discharge tray; and a guide member for guiding the sheets to the sheet discharge means. A driving unit for applying a driving force to the sheet discharging unit, and a detecting unit upstream of the sheet discharging unit for detecting the presence or absence of a sheet on the guide member. A sheet discharging device, wherein after a predetermined period of time has passed after passing through the detecting means for detecting the absence, the discharge control of the driving means is performed at a lower speed than the discharging speed of the normal sheet. 2. A discharge tray for stacking sheets to be discharged along a transport path, a discharge roller for discharging the sheets onto the discharge tray, and a discharge roller facing and abutting the discharge roller. A driven roller that pinches and conveys the sheet; a guide member that guides the sheet to the discharge roller; a driving unit that applies a driving force to the discharge roller; and a driving force of the driving unit that is transmitted to the discharge roller. A drive transmitting means, and a detecting means for detecting the presence or absence of a sheet on the guide member upstream of the discharge roller in the sheet conveying direction, wherein the drive transmitting means detects the presence or absence of the sheet at the rear end of the sheet. A sheet discharge device that discharges a sheet discharged from a paper discharge roller at a speed lower than a normal discharge speed after a lapse of a predetermined time after passing through the sheet discharging device. 3. A deceleration means of said drive transmission means includes a first drive train including an electromagnetic clutch means capable of turning on / off a drive transmission from a drive source, and a paper discharge by a different system from said electromagnetic clutch means. 3. The sheet discharging device according to claim 2, further comprising a second drive train for transmitting drive to the rollers, wherein the second drive train is provided with a one-way rotation transmission clutch.