JPH047262A - Sheet conveyer for picture forming device - Google Patents

Abstract

PURPOSE:To provide even a transcription sheet of small size surely and further by stable timing to fixing operation by providing rotary kickers for a small size sheet, so as to be made possible to protrude/retract to/from a conveying path, in a suitable part between suction conveying belts. CONSTITUTION:Kickers 96 are retracted downward from a conveying path 100 by a porous belt 94 to give no influence at all to a conveyed transcription sheet 2 by holding a lever 97 normally in a downward-moving position by energizing force of a spring 99. In the case that the transcription sheet 2, fed by hand has the same size as a government post card, the kicker 96 is moved upward by turning on a solenoid 98 to turn the lever 97 in the clockwise direction. Consequently, when and after the kicker 96 advances to a conveying path 100 reaches the rear end of the transcription sheet 2 conveyed by the porous belt 94, the kicker 96 acts on the rear end and is forcedly fed to a fixer. Even in the case of weak suction conveyance by the porous belt caused by the small size, the transcription sheet 2 can be surely presented for fixing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sheet conveying device for an image forming apparatus such as a copying machine or a printer that forms an image using an electrophotographic method. The present invention relates to a sheet conveyance device that conveys a sheet using a belt.

BACKGROUND ART This type of sheet conveying device conveys a transfer sheet, on which a toner image has been transferred to the top surface, in an adsorbed state by suctioning it from the back side, reliably conveys the transferred image without damaging it, and then transfers it to the next fixing stage. can be provided. However, in recent years, images have been formed on smaller (and thicker) sheets such as government postcards.The suction area is small and the paper has to be curled. If this happens, a gap may be created between the suction conveyor belt and the suction action may be difficult or insufficient, causing problems when feeding to the next fixing device.Resolve this problem. 1. Unexamined Japanese Patent Publication No. 1983-
Publication No. 51454 and 2. A method disclosed in Japanese Utility Model Application Publication No. 62-92251 is known.

The device disclosed in the first publication has a cut-out piece in a part of the suction conveyance belt, which is normally at the same height as the conveyance surface and protrudes by a predetermined height toward the back side, and this cut-out piece is made small. The transfer sheet is pushed out onto the conveying surface of the suction conveying belt only when conveying the transfer sheet of the same size.

The device disclosed in the second publication has a plurality of protrusions arranged in the conveying direction on the conveying surface of the suction conveying belt.

Problems to be Solved by the Invention However, in all of these, small-sized sheets are pushed and conveyed using cutouts or protrusions formed on the suction conveyance belt itself. For this reason, the cutouts and protrusions do not initially face the rear end of the sheet conveyed by the conveyor belt, and even though the sheet has reached the fixing device, the suction conveyor belt is weak in conveying the sheet. If the sheet cannot be penetrated and progress stops, the cutout or protrusion that was located behind the rear edge of the sheet will reach the rear edge of the sheet and begin to push it, and from this point on, the sheet will not be fixed. It will be forced into the container. For this reason, the timing at which the sheet enters the fixing device varies each time, and it is necessary to increase the interval between sheet conveyances, which impairs high-speed performance.There are also inconveniences such as making it difficult to jump jams when controlling sheet conveyance. .

Furthermore, in the device disclosed in the first publication, the protrusions are always located on the conveyance surface of the suction conveyance belt, which actually hinders the suction when conveying the sheet, making it difficult to convey when conveying normal-sized sheets. I don't like to damage it. Furthermore, in the second publication, although the cutout pieces are designed to protrude onto the conveyance surface only when necessary, each time they pass through a roller section on which a suction conveyance belt is stretched, the cutout pieces move toward the conveyance surface. As the cutout pieces are pushed out and moved in and out repeatedly, fatigue due to deformation accumulates at the base, which tends to damage the base, shortening the life of the suction conveyance heald.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a sheet conveyance device for an image forming apparatus that can reliably convey small-sized sheets without the above-mentioned problems.

Means for Solving the Problems In order to achieve the above-mentioned problems, the present invention provides a sheet conveyance device of an image forming apparatus in which a transfer sheet after transfer is conveyed by a plurality of suction conveyance belts. The present invention is characterized in that a rotating kicker for small-sized sheets is provided so as to be movable in and out of the conveyance path, and the cutter is moved forward to work on the transfer sheet only when a small-sized transfer sheet is being conveyed. It is something.

Function According to the above structure of the present invention, only when a small-sized transfer sheet is conveyed, the rotating kicker is advanced into the conveying path from between the plurality of suction conveying belts and is operated, so that the small-sized transfer sheet is conveyed. As soon as the transfer sheet is moved, the rear end is pushed, so even if the suction conveyance belt is weak, it is possible to forcibly convey the small size transfer sheet without any stagnation and ensure that it enters the fixing device. .

Further, when conveying a normal size transfer sheet, the rotary pusher is retracted from the conveyance path, so it does not affect the conveyance of the normal size transfer sheet.

Embodiment Hereinafter, a sheet conveying device as an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

FIG. 1 shows a copying machine having a sheet conveying device according to the present invention. This copying machine includes an exposure optical system 1, an image forming mechanism 3 that forms an image through exposure by the exposure optical system 1 and transfers it to a transfer sheet 2, and a paper feeder that feeds the transfer sheet 2 to the image forming mechanism 3. It has a mechanism 4. These exposure optical system 1, image forming mechanism 3, and paper feeding mechanism 4 are independent optical system box 6, image forming box 7, and paper feeding box 8.
are housed separately. The boxes 6 to 8 are stacked and connected to form a fuselage 9.

The exposure optical system 1 includes a lamp 13 that is supported by a first slider 12 that moves under a platen glass 11 to scan an original on the platen glass 11, a first mirror 14, a second slider 15, and a third slider 16. The second to fifth mirrors 17 to 20 move to keep the optical path length constant.
, a projection lens 21 provided between each of the third and fourth mirrors 18 and 19, and a sixth mirror 22 that performs optical path length correction during zooming by moving the projection lens 21 in the optical axis direction.

The image forming mechanism 3 includes a photosensitive drum 31, a charging charger 32 disposed around the photosensitive drum 31, a developing device 33, a transfer charger 34, a separation charger 135, and a cleaning device 136.
etc., and a photosensitive drum 31 using a known electrophotographic method.
A toner image corresponding to the original image to be exposed is formed thereon, and the toner image is transferred to the transferred transfer sheet 2. In front of the transfer section where the photosensitive drum 31 and the transfer charger 34 face each other, there is provided a paper feed conveyance path 35 for feeding the transfer sheet 2 received from the paper feed box 8 to the transfer section, and a timing roller is provided on the way. 36 are provided. The timing roller 36 is fed the transfer sheet 2 in a stopped state, and corrects the skew of the transfer sheet 2 by aligning its leading edge, and adjusts the timing of feeding the transfer sheet 2 to the transfer section depending on when to start conveyance. .

After the transfer unit, there is a conveying device 37 that conveys the transfer sheet 2 after transfer while adsorbing it to an aeration belt, and a fixing device that performs a fixing process on the transfer sheet 2 conveyed by the conveying device 137. Transfer sheet 2
A paper discharge roller 39 is provided to discharge the paper.

The paper feeding mechanism 4 includes three paper feeding sections 41 to 41 that accommodate transfer sheets 2 of different sizes and selectively feed the sheets according to the size specification on the operation panel 91 provided on the front of the machine body 9.
It has 43. Each of the paper feed units 41 to 43 includes pickup rollers 47 to 49 that feed out the transfer sheets 2 in the paper feed cassettes 44 to 46, and transfer sheets 2 that are fed out.
It has a sorting pad 51 for sorting the pieces one by one. Each of the paper feed sections 41 to 43 is divided into blocks, so that the blocks can be replaced by replacing two blocks with one block for a large number of sheets. The paper feeding power centers 44 to 46 of the paper feeding units 41 to 43 are respectively inserted and removed from the front side of the machine body 9, in FIG. 1, from the front side of the page.

A manual paper feed path 61 is provided in a portion of the paper feed conveyance path 35 in front of the timing roller 36 to connect a manual paper feed table 60 provided in an example of the machine body 9 . A paper feed roller 62 is provided in the manual paper feed path 61 . The paper feed roller 62 is driven when a sensor (not shown) detects the transfer sheet 2 that is manually fed from the manual paper feed tray 60, and feeds the transfer sheet 2 through the manual paper feed path 61 to the paper feed conveyance path 35 for transfer. 63 in the figure indicates a manual paper feed slot.

As shown in FIGS. 2 to 5, the manual paper feed tray 60 includes a paper feed tray main body 66 that is pivotably supported to an example of the body 9 by a shaft 64 so as to be openable and closable, and a rear portion inside the paper feed tray main body 66. and an auxiliary paper feed tray 67 that is retractably stored.

A pair of left and right side guides 68 and 69 for guiding the manually fed transfer sheet 2 from the sides are provided on the paper feed table main body 66 so as to be movable toward and away from the side guides 68 and 69. This side guide 68.6
9 are moved toward and away from each other in conjunction with each other by racks 71, 72, and pinion 73, so that the transfer sheets 2 are positioned on a common paper passing center for each size.

The paper feed table main body 66 also includes the one side guide 68.
Three photosensors 81 to 83 are provided to detect the size of the sheets to be loaded depending on the moving position of the sheet, and are adapted to detect a protrusion 71a provided on the rack 71 linked to the side guide 68. Also, the auxiliary paper feed tray 67 is the second one.
As shown in FIGS. 5 and 5, the transfer sheet 2 of large size is
However, a photo sensor 84 is provided to detect the rear end of the large-sized transfer sheet 2 to be received in this state. The photosensor 84 has an actuator 85 protruding from the window 67a on the top surface of the auxiliary paper feed table 67, and detects whether or not this actuator is pushed by the rear end of the transfer sheet 2, and determines whether the size of the transfer sheet 2, I'm trying to distinguish between small and small.

The lead wire 86 of the photosensor 84 has a flexible portion 86a between the auxiliary sheet feed tray 67 and the sheet feed tray main body 66, and is connected to the machine body 9, which is the sheet receiving device, through the shaft 64. It is drawn in and connected to the control device 87. This prevents the wiring from interfering with the opening and closing of the paper feed tray main body 66 and from being damaged by the opening and closing.

An example of sheet size detection by each of these sensors 81 to 84 is shown in the table below. This example shows the case of determining the A column, B column, and postcard size according to the JIS standard.

The manual paper feed tray 60 can guide and manually feed large and small transfer sheets 2 even when the auxiliary paper feed tray 67 is stored as shown in FIGS. 1, 3, and 4. In this case, the actuator 85 is pushed down by the upper wall of the paper feed table main body 66 as shown in FIG. 3, and the photosensor 84 performs the same detection as the detection state of the large-sized transfer sheet 2 described above. This allows the large size transfer sheet 2
It is possible to avoid a situation in which a copying machine is stopped due to a long paper feeding time even though the paper is manually fed. Even if a small size is treated as a large size, there will be no problem in determining a jam.

As shown in FIGS. 1 and 6 to 8, the conveyance device 37
It is composed of a plurality of perforated belts 94 stretched by a driving roller 92 and a driven roller 93, and a suction box 95 provided inside the perforated belts. It is adsorbed to the conveying surface of the paper and conveyed. However, if the transfer sheet 2 is small and thick, such as a government postcard, the suction area is small, and if it is curled, a gap will be created between it and the porous heald 94, which will hinder suction. However, there is a disadvantage that it is not possible to ensure that the liquid enters the fixing device 38.

To solve this problem, a rotary kicker 96 is provided between each perforated belt 94 to reliably convey the small-sized transfer sheet 2. The kicker 96 is rotatably held by a pair of levers 97 whose ends are pivotally supported by a driven roller 93, and is driven from the driven roller 93 via a timing belt 90. A passive piece 97a is protruded from one lever 97, and a solenoid 98 is connected to this.

The lever 97 is normally held in the downward position shown in FIG. 7 by the bias of a spring 99, causing the kicker 96 to retreat downward from the conveyance path 100 formed by the perforated belt 94. As a result, the kicker 96 does not affect the transfer sheet 2 conveyed by the conveyance device 37 at all.

When the size of the transfer sheet 2 specified on the operation panel 91 or manually fed from the manual paper feed stand 60 corresponds to a government postcard, the solenoid 98 is turned on. As a result, the lever 97 is rotated clockwise,
The kicker 96 is moved upward as shown in FIGS. 6 and 8. For this reason, the kicker 96 advances into the conveyance path 100, and after reaching the rear end of the transfer sheet 2 conveyed by the perforated belt 94, it acts on the rear edge to forcibly feed it to the fixing device 38 and securely feed it to the fixing device 38. Let it rush in. Therefore, even if suction and conveyance by the porous belt is weak due to the small size, the transfer sheet 2 can be reliably fixed without being delayed in the slightest.

FIG. 6a shows a modification of the present invention, in which a protrusion 96b that engages with the hole 94a of the perforated belt 94 is formed on the rotating shaft 96a of the kicker 96, so that when the kicker 96 is moved upward, , the protrusion 96b and the hole 94a are engaged, and the kicker 9
6 is configured to forcibly convey the transfer sheet 2 by following the perforated belt. In this case, the structure is further simplified,
In the lower movement position, the stopped state can be achieved without independent drive control.

Effects of the Invention According to the present invention, only when conveying a small-sized transfer sheet, the rotary kicker is advanced into the conveying path from between the plurality of suction conveying belts and is operated, and the small-sized transfer sheet is conveyed. Even if the conveyance of the suction conveyance belt is weak, the small-sized transfer sheet will be forcibly conveyed without any stagnation and will surely enter the fixing device by pushing the rear end. Even transfer sheets can be used for fixing reliably and at a stable timing, and there is no need to set conveyance intervals that take transfer sheet conveyance delays into consideration, ensuring high speed, and it is easy to judge jams. .

In addition, when transporting a normal size transfer sheet, the rotary kicker is retracted from the transport path, so it does not affect the transport of the normal size transfer sheet, and there is no problem with durability, and it has a long life. becomes.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a longitudinal sectional front view of a copying machine having a sheet III feeding device as an embodiment of the present invention, and FIGS. 4 and 5 are perspective views showing the expanded/contracted state of the paper feed tray, FIG. 6 is a schematic perspective view of the conveying device, and FIG. 6a is a perspective view of a part of the carrier showing a modified example of the present invention. 7 and 8 are side views showing the operating state of the kicker in the conveying device. 81~84 85・----・Transfer sheet machine paper feed stand Photo sensor actuator・・Timing belt operation panel・・−Porous belt・・・−Hole・・−・−Kitsuka・・−Protrusion solenoid

Claims (1)

[Claims] (1) In a sheet conveyance device of an image forming apparatus in which a transfer sheet after transfer is conveyed by a plurality of suction conveyance belts,
A rotary kicker for small-sized sheets is installed at an appropriate location between the suction and conveyance belts so that it can move in and out of the conveyance path, and the kicker advances and works on the transfer sheet only when a small-size transfer sheet is being conveyed. A sheet conveying device for an image forming apparatus, characterized in that: