JP3933730B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, printer, facsimile, and the like. The present invention relates to a forming apparatus.
[0002]
[Prior art]
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 in the middle, a paper feed unit is disposed below, a paper discharge unit is disposed above, and the paper is discharged with the image surface facing downward. Compared to conventional copying machines, the transport path is very short, and most of the transport path can be opened simply by opening the side of the device. Very good jam removal.
[0003]
[Problems to be solved by the invention]
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-treatment equipment, the improvement of the mechanical strength of the image forming apparatus is required, has such unavoidable cost increase due to this.
[0004]
Therefore, an object of the present invention is to provide an image forming apparatus that can use post-processing equipment while suppressing the influence on the height and mechanical strength of the apparatus main body .
[0005]
[Means for Solving the Problems]
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 apparatus main body, and the post-processing apparatus communicates with the paper discharge unit of the apparatus main body.
Specifically, according to the first aspect of the present invention, a scanner unit that reads an image of a document, an image forming unit that forms a target image on a sheet material, and a discharge provided between the scanner unit and the image forming unit. In the image forming apparatus in which the sheet material on which the target image is formed by the image forming unit is stacked via the paper discharge unit, the paper discharge unit is provided on one side of the apparatus main body. A sheet material transport unit that communicates between the post-processing device mounted on the other side facing the one side of the apparatus main body and the paper discharge unit is provided between the scanner unit and the image forming unit , The sheet material transport unit includes a stack unit provided on an upper surface of the sheet material transport unit for stacking image-formed sheet materials ejected from the sheet ejection unit, and the sheet material ejected from the stack unit. Transport to stack A stack transport path, a post-process transport path for transporting the sheet material to the post-processing device, and switching of the sheet material into the post-process transport path and the stack transport path. The stack transport path is shorter than the post-processing transport path.
[0006]
In the second aspect of the present invention, in the structure according to claim 1, wherein the stack face of the stack portion has an inclined portion rising toward the discharge direction downstream side, that has adopted the configuration that.
[0007]
【Example】
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. A sheet feeding unit 8 is disposed below the image forming unit 6. A paper discharge unit 12 is provided above one side . A scanner 18 serving as a scanner unit for reading a document is installed further above the apparatus main body 4 via scanner stands 14 and 16, and a stack unit 20a is provided on the other side of the apparatus main body 4 opposite to the one side surface. A post-processing device 20 such as a sorter, a stapler, or a finisher having the above is mounted.
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.
[0008]
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.
By the above-described serial arrangement in the vertical direction with the image forming unit 6 in the above, the sheet path extends in a substantially vertical direction, that is, from the paper supply unit 8 through the image forming unit 6 to the paper discharge unit 12. P is formed.
[0009]
The image forming unit 6 mainly includes a photoconductor 32 as an image carrier that is driven to rotate 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 image data from the scanner 18 into an optical signal and performs optical writing corresponding to the original 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.
[0010]
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.
[0011]
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.
[0012]
The main process equipment of the image forming unit 6, the paper feed 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 come to be. This facilitates jam processing.
[0013]
The sheet material transport unit 22 is provided on the upper surface of the sheet material transport unit 22, and stacks 68 for stacking image-formed sheet materials discharged from the paper discharge unit 12. A stack conveying unit 70 that conveys the sheet material from the paper unit 12, a post-processing conveyance unit 72 that conveys the sheet material to the post-processing device 20, and a branch unit 74 that switches the path of the sheet material that has exited from the paper discharge unit 12. And a control means 76 (FIG. 2) for controlling the branching means 74.
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 means 70 has a sheet path 75 as a stack conveying path that communicates between the paper discharge unit 12 and the stack unit 68, and is positioned downstream of the sheet path 75, and the sheet material is supplied to the stack unit 68. A paper discharge roller 77 for discharging paper is provided.
The post-processing transport means 72 is positioned downstream of the sheet path 79 as a post-processing transport path for communicating between the paper discharge unit 12 and the post-processing device 20, transport rollers 80 and 81, and the sheet path 79. The sheet discharge roller 82 discharges the sheet material to the post-processing device 20, and the sheet material detection sensor 83 located between the conveyance rollers 80 and 81. 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 sheet path 75 as the stack conveyance path is set shorter than the sheet path 79 as the post-processing conveyance path.
The branching means 74 includes a branching claw 74a and a solenoid 74b (FIG. 2) that drives the branching claw 74a.
[0014]
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.
[0015]
Next, the image forming operation and the operation of the sheet material transport unit 22 will be described.
Optical writing is performed by the optical writing device 34 according to information on the surface of the photoreceptor 32 whose surface is uniformly charged by the charger 36, 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 means 70 is opened, and the sheet material 28 or 30 is conveyed by the stack conveying means 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.
[0016]
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.
[0017]
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.
[0018]
As described above, the post-processing device 20 is mounted so as not to be bulky with respect to the apparatus main body 4 or in a state where no weight is added to the apparatus main body 4. By using a configuration in which the paper 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.
[0019]
【The invention's effect】
According to the present invention, when post processing is not necessary because it is discharged from a stack of the sheet material conveying unit, Ru can be shortened in the first copy time.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an image forming apparatus showing an embodiment of the present invention.
FIG. 2 is a control block diagram.
FIG. 3 is a side view of a main part showing a state in which the sheet material is conveyed to a stack part of a sheet material conveyance unit.
FIG. 4 is a side view of a main part showing a state of transport to a post-processing device.
FIG. 5 is a side view of a main part showing a state in which the sheet material conveying unit is stacked on the post-processing device when the stack portion is full.
FIG. 6 is a flowchart showing the operation of the sheet material transport unit.
[Explanation of symbols]
6 Image forming means section 8 Paper feed section 12 Paper discharge section 20 Post-processing device 22 Sheet material transport units 28 and 30 Sheet material 58 Paper discharge sensor 68 as sheet material detection sensor Stack section 70 Stack transport means 72 Post-process transport Means 74 Branch means 76 Control means 78 Sheet fullness detection sensor as sheet fullness detection means

Claims (2)

A scanner unit that reads an image of an original; an image forming unit that forms a target image on a sheet material; and a paper discharge unit that is provided between the scanner unit and the image forming unit. In the image forming apparatus in which the sheet material on which the image is formed is stacked through the paper discharge unit,
The sheet discharge unit is provided on one side of the apparatus main body, and a sheet material transport unit that communicates the sheet discharge unit with a post-processing device mounted on the other side facing the one side of the apparatus main body. The sheet material conveyance unit is provided between the scanner unit and the image forming unit , and the sheet material conveyance unit is provided on the upper surface of the sheet material conveyance unit for stacking the image-formed sheet material discharged from the paper discharge unit. A stack transport path for transporting the discharged sheet material to the stack section, a post-processing transport path for transporting the sheet material to the post-processing device, and the post-processing An image forming apparatus comprising: a branching unit configured to switch the sheet material into the stack transport path and the stack transport path, wherein the stack transport path is shorter than the post-processing transport path. 2. The image forming apparatus according to claim 1, wherein the stack surface of the stack portion has an inclined portion that rises toward the downstream side in the paper discharge direction .

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