JP3754049B2 - Image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, and the like. The present invention relates to a forming apparatus.

In recent years, image forming apparatuses having a composite function such as a copying machine, a printer, and a facsimile have become widespread. Until now, such an image forming apparatus is only based on a copying machine, and when used as a printer, a reversing mechanism is mounted on a peripheral device or the like in order to output in page order. However, with the recent rapid spread of personal computers, the construction of printer bases is becoming main.
This employs a substantially vertical path method, that is, a method in which an image forming unit is placed inside and a paper feeding unit is disposed below, a paper discharging unit is disposed above, and the paper is discharged with the image surface facing downward. Compared with other copiers, the transport path is very short, and most of the transport path can be opened simply by opening the side of the machine. Removability is very good.

JP-A-4-280774

However, there is a problem that it is difficult to mount post-processing devices such as a sorter, a stapler, and a finisher.
Specifically, since the upper part of the image forming apparatus serves as a sheet material discharge port, if the post-processing device is installed directly there, the height of the entire apparatus increases, and accordingly, the scanner as a document table The operation section becomes high and the operability becomes poor. Also, the height of the apparatus is naturally limited due to operability, and it is practically impossible to arrange many trays. Furthermore, since the image forming apparatus receives the weight of the post-processing equipment, it is required to improve the mechanical strength of the image forming apparatus, and an increase in cost due to this is inevitable.
As described above, when the post-processing device is used, there is a problem that the advantage of the substantially vertical path method cannot be fully utilized.

  Accordingly, an object of the present invention is to provide an image forming apparatus that can use post-processing equipment while fully utilizing the advantages of the substantially vertical path method.

The present invention is based on the idea that the post-processing device is installed at a position where no problems such as height and weight occur with respect to the image forming apparatus and the post-processing device communicates with the paper discharge unit of the image forming apparatus. .
Specifically, the invention described in claim 1 includes a scanner for reading a document, an image forming unit that forms a target image on a sheet material, and a paper discharge unit provided between the scanner and the image forming unit. In an image forming apparatus in which a sheet material on which a target image is formed by the image forming unit is stacked via the paper discharge unit, the sheet material is provided between the scanner and the image forming unit, and the paper discharge A sheet material conveying unit that is connected to the image forming unit and includes a conveying path for conveying a sheet material from the paper discharging unit to one side surface of the apparatus main body, and is provided between the scanner and the image forming unit. comprising a stacking unit for stacking the sheet material to be discharged, and a branching means for switching the path of the sheet material exiting the discharge unit to any one of the sheet material conveying unit and the stack unit from the sheet material conveying Knit adopts a configuration in which space the sheet material is discharged above the stack portion is formed in a state of being connected to the discharge unit.

In the invention according to claim 2, in the configuration according to claim 1, a cover for preventing contact with the sheet material stacked on the stack portion is provided on one side of the transport surface of the transport path. The composition is taken.
According to a third aspect of the present invention, in the configuration of the second aspect , the stack portion is disposed on the sheet material transport unit, and the upper surface of the cover also serves as a stacking surface of the stack portion. The

According to the first aspect of the present invention, the sheet material is not exposed when the sheet material is conveyed to one side surface of the apparatus main body, and the operator can be prevented from accidentally pulling out the sheet material.
According to the second aspect of the present invention, the sheet material is not exposed when the sheet material is conveyed to one side surface of the apparatus main body, and the operator can be prevented from accidentally pulling out the sheet material.

According to the invention of claim 3 wherein, without the sheet material is exposed in transporting the sheet to one side of the apparatus main body, Ru prevents pulling the sheet material by mistake the operator.

An embodiment of the present invention will be described below with reference to FIGS.
As schematically shown in FIG. 1, an image forming unit 6 is provided in the apparatus body 4 of the image forming apparatus 2, and a sheet feeding unit 8 is disposed below the image forming unit 6. Is provided with a paper discharge unit 12. A scanner 18 for reading a document is installed above the apparatus main body 4 via scanner stands 14 and 16, and a post-processing such as a sorter, a stapler, and a finisher having a stack portion 20a is provided on one side of the apparatus main body 4. The device 20 is attached. The scanner tables 14 and 16 are provided between the paper discharge unit 12 and the scanner 18. A paper discharge unit 12 is provided between the scanner 18 and the image forming unit 6. The paper discharge unit 12 is provided on the other side surface of the apparatus main body 4 facing the one side surface.
On the upper surface of the apparatus main body 4, a sheet material conveyance unit 22 having a unique conveyance path and a conveyance function is provided along the upper surface. The sheet material transport unit 22 is provided between the scanner 18 and the image forming unit 6.

The paper feed unit 8 is provided with a plurality of paper feed cassettes 24 and 26, each of which accommodates sheet materials 28 and 30 having different sizes, for example.
With the above-described serial arrangement in the vertical direction with the image forming unit 6 in the middle, the sheet path P extends in a substantially vertical direction, that is, the sheet path P extends from the paper supply unit 8 through the image forming unit 6 to the paper discharge unit 12. Is formed.

The image forming unit 6 mainly includes a photoconductor 32 as an image carrier that is rotationally driven counterclockwise, and an optical writing device 34 that forms an electrostatic latent image on the photoconductor 32. More specifically, around the photoconductor 32, a charger 36 for uniformly charging the photoconductor 32, an eraser (not shown) for erasing the non-image portion charge, and an electrostatic latent image are visualized. A developing device 38 that transfers the visible image formed by the developing device 38 to a sheet material, and removes the toner remaining on the photoconductor 32 after the transfer, and the photoconductor. A cleaning unit 42 for cleaning 32 and a charge eliminator (not shown) for erasing charges remaining on the photoconductor 32 after transfer are provided. In addition, a fixing device 44 that melts and fixes the toner image transferred by the transfer device 40 is provided between the transfer device 40 and the paper discharge unit 12.
The optical writing device 34 is a unit that converts the image data from the scanner 18 into an optical signal and performs optical writing corresponding to a document image and optical writing according to image information from a personal computer. Is scanned through a polygon mirror, and scanning light is guided to the photoconductor 32 by an fθ lens through a reflecting mirror to form an electrostatic latent image.

  The sheet material 28 or 30 is fed by the sheet feed roller 46 and separated one by one by the separation roller pair 48, and is conveyed in a substantially vertical sheet path by the conveyance roller 50. A registration roller pair 52 for feeding the sheet material 28 or 30 between the transfer device 40 and the photosensitive member 32 at a predetermined timing is disposed in front of the transfer device 40. A material detection sensor 54 is provided.

The paper discharge unit 12 is provided with a paper discharge roller 56, and a paper discharge sensor 58 as a sheet material detection sensor located at the most downstream side of the substantially vertical sheet path is provided in front of the paper discharge roller 56. ing.
The scanner 18 is configured to return a contact glass 60 for placing a document, a white pressure plate 61 for pressing the document, an illumination lamp 62 for irradiating light on the document placed on the contact glass 60, and reflected light from the surface of the document. It comprises a scanning mirror 63 that reflects, a pair of optical path folding mirrors 64 a and 64 b that move at half the speed of the scanning mirror 63, an imaging lens 66, and a CCD 67.

The main process equipment of the image forming unit 6, the paper feeding unit 8, and the paper discharge unit 12 are built in the apparatus main body 4, and most of the substantially vertical sheet path is opened by opening the side plate 4a of the apparatus main body 4. It has become so. This facilitates jam processing.

The sheet material conveyance unit 22 includes a stack unit 68 for stacking image-formed sheet materials discharged from the paper discharge unit 12, and a stack conveyance unit that conveys the sheet material from the paper discharge unit 12 to the stack unit 68. Means 70, post-processing transport means 72 for transporting the sheet material to the post-processing device 20, branch means 74 for switching the path of the sheet material that has exited from the paper discharge unit 12, and control means 76 for controlling the branch means 74 ( 2). The stack unit 68 is provided between the scanner 18 and the image forming unit 6.
The stack unit 68 is provided with a sheet full detection sensor 78 as a sheet full detection unit that detects that the sheet material is full.
The stack conveying unit 70 includes a sheet path 75 that communicates between the sheet discharge unit 12 and the stack unit 68, and a sheet discharge roller that is positioned downstream of the sheet path 75 and discharges the sheet material to the stack unit 68. 77 that have been provided.
The post-processing transport unit 72 is positioned downstream of the sheet path 79 as a transport path for communicating between the paper discharge unit 12 and the post-processing device 20, the transport rollers 80 and 81, and the rear path. A sheet discharge roller 82 that discharges the sheet material to the processing device 20 and a sheet material detection sensor 83 positioned between the conveyance rollers 80 and 81 are configured. One side (upper side) of the conveyance surface of the sheet path 79 is a cover that prevents contact between the sheet material stacked in the stack unit 68 and the sheet path 79, and the upper surface of this cover covers the stacking surface of the stack unit 68. Also serves as. The stack unit 20a of the post-processing device 20 is also provided with a sheet full detection sensor 83 as a sheet full detection unit.
The branching means 74 includes a branching claw 74a and a solenoid 74b (FIG. 2) that drives the branching claw 74a.

  As shown in FIG. 2, the control means 76 as a microcomputer receives detection signals from the paper discharge sensor 58, the sheet full detection sensor 78, the sheet full detection sensor 83, etc., and the control means 76 is based on these information. Thus, the solenoid 74b of the branching means 74 is turned on / off. When processing is performed by the post-processing device 20, settings are made via the operation panel 84.

Next, the image forming operation and the operation of the sheet material transport unit 22 will be described.
The optical writing device 34 performs optical writing on the surface of the photosensitive member 32 whose surface is uniformly charged by the charger 36 in accordance with information on the image of the original read by the scanner 18 or the image from the personal computer. An electrostatic latent image is formed. The electrostatic latent image on the photoconductor 32 is formed with a visible image by attaching the toner charged by the developing device 38 after the charge of the non-image portion is erased by the eraser.
On the other hand, for example, the sheet material 28 is fed from the sheet feeding cassette 24 of the sheet feeding unit 8 by the sheet feeding roller 46, separated one by one by the separation roller 48, and sent into the sheet path. The registration roller pair 52 sends the sheet material 28 to the transfer device 40 at a timing at which the visible image on the photoconductor 32 and the sheet material 28 coincide at the nip portion between the photoconductor 32 and the transfer belt.

The sheet material 28 to which the toner image has been transferred is sent to a fixing device 44 where the toner image is heated and fixed to the sheet material 28.
The sheet material on which the image has been formed is discharged from the paper discharge unit 12, but when a mode that does not require processing in the post-processing device 20 is selected, as shown in FIG. Is turned on, and the branch claw 74a rotates downward. As a result, only the sheet path 75 of the stack conveying unit 70 is opened, and the sheet material 28 or 30 is conveyed by the stack conveying unit 70 and stacked on the stack unit 68. This is a so-called normal paper discharge operation.
When a mode to be processed by the post-processing device 20, for example, a staple mode is selected, as shown in FIG. 4, only the sheet path 79 of the post-processing transport means 72 is opened while the solenoid 74b remains off. . The sheet material 28 or 30 discharged from the paper discharge unit 12 is transported by the post-processing transport means 72 and sent to the post-processing device 20. Although not shown, the sheet material 28 or 30 is stacked on the stack unit 20a after a predetermined job such as stapling is completed in the post-processing device 20.

Although normal discharge can be performed to the stack unit 20a of the post-processing device 20, in order to shorten the so-called first copy time, the normal discharge is performed by stacking the sheet material transport unit 22 unless post-processing is necessary. To part 68.
The reason why opening of the post-processing transport means 72 is made to correspond to the off position of the solenoid 74b is that the post-processing device 20 has a larger number of stacks, so that the continuous sheet passing time may be longer. This is to reduce the size and cost of the solenoid 74b by reducing the duty of 74b.
Although not shown, the post-processing device 20 has a stapling function inside.

Next, the relationship between the stack function and the sheet full detection sensor 78 will be described.
When a mode that does not require processing in the post-processing device 20 is selected and a job that exceeds the number of stacks in the stack unit 68 of the sheet material transport unit 22 is executed, as shown in FIG. Based on the detection signal from the full detection sensor 78, the control means 76 turns off the solenoid 74 b and switches the conveyance path to the post-processing conveyance means 72. Accordingly, image formation can be continuously performed at a time for the total number of sheets of the sheet material transport unit 22 and the number of stacks of the post-processing device 20.
Based on the information of the sheet fullness detection sensor 83, the above switching may not be performed when the stack unit 20a of the post-processing device 20 is full.
FIG. 6 is a flowchart of the above operation. As can be seen, the solenoid 74b is turned on based on the detection signal of the paper discharge sensor 58 located on the most downstream side of the sheet path of the apparatus body 4.
The sheet full detection sensor 78 has a configuration in which, for example, a swingable arm is moved by a sheet material discharging operation, and its return position is detected to determine fullness. Since this is a well-known technique disclosed in, for example, Japanese Patent Laid-Open No. 4-280774, details are omitted.

  As described above, the post-processing device 20 is mounted so that the height thereof is not bulky with respect to the apparatus main body 4 and no weight is added to the apparatus main body 4, and the post-processing device 20 and the apparatus main body 4 are discharged. By using a configuration in which the unit 12 is connected to the sheet material conveyance unit 22 provided along the upper surface of the apparatus main body 4, the post-processing device 20 can be used without diminishing the advantages of the substantially vertical path method. I can do it.

1 is a schematic side view of an image forming apparatus showing an embodiment of the present invention. It is a control block diagram. It is a principal part side view which shows the state conveyed to the stack part of a sheet material conveyance unit. It is a principal part side view which shows the state conveyed to a post-processing apparatus. It is a principal part side view which shows the state which stacks to a post-processing apparatus, when the stack part of a sheet material conveyance unit becomes full. It is a flowchart which shows operation | movement of a sheet material conveyance unit.

Explanation of symbols

6 Image forming unit 8 Paper feeding unit 12 Paper discharge unit 20 Post-processing device 22 Sheet material conveyance unit 28, 30 Sheet material 58 Paper discharge sensor as sheet material detection sensor 68 Stack unit 70 Stack conveyance unit 72 Post-processing conveyance unit 74 Branch means 76 Control means 78 Sheet full detection sensor as sheet full detection means

Claims (3)

A scanner that reads a document; an image forming unit that forms a target image on a sheet material; and a paper discharge unit that is provided between the scanner and the image forming unit. The target image is formed by the image forming unit. In an image forming apparatus in which stacked sheet materials are stacked via the paper discharge unit,
A sheet material conveyance unit provided between the scanner and the image forming unit and connected to the paper discharge unit and including a conveyance path for conveying the sheet material from the paper discharge unit to one side surface of the apparatus main body; A stack unit that is provided between the scanner and the image forming unit and stacks the sheet material discharged from the paper discharge unit; and a path of the sheet material output from the paper discharge unit and the sheet material conveyance unit. Branching means for switching to one of the stack parts, and a space for discharging the sheet material is formed above the stack part in a state where the sheet material transport unit is connected to the paper discharge part. An image forming apparatus.   The image forming apparatus according to claim 1, wherein a cover for preventing contact with the sheet material stacked on the stack portion is provided on one side of the conveyance surface of the conveyance path.   The image forming apparatus according to claim 2, wherein the stack unit is disposed on the sheet material transport unit, and an upper surface of the cover also serves as a stacking surface of the stack unit.

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