JPH0243144A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is directed to a paper transport path that passes through an image transfer section formed between an image bearing member and a transfer device and then reaches a fixing device. The present invention relates to an image forming apparatus having a built-in paper conveying device (ADD) that can guide the paper that has passed through the fixing device to the image transfer section again.

(Prior Art) In recent years, various functions have become more versatile, and various image forming apparatuses capable of double-sided copying have been put into practical use.

Normally, in this type of image forming apparatus, a sheet of paper that has passed through the fixing device is placed below a paper conveyance path from a pair of registration rollers, through an image transfer section formed between an image bearing member and a transfer device, and then to a fixing device. The structure includes a built-in paper conveying device that can temporarily accumulate paper in a stacker and guide it to the image transfer section again.

Conventionally, the paper conveyance device has a structure in which the paper sent out from the fixing device is conveyed to a stacker via a conveyance path formed by a pair of guide plates and a pair of conveyance rollers.

(Problem to be Solved by the Invention) However, in a conventional device in which a pair of guide plates and a pair of conveyor rollers are arranged to configure a path for conveying paper to a stacker, the structure is complicated due to the large number of parts. This not only results in high costs, but also has the problem that there is little space above the stacker, making it difficult to remove sheets jammed in the stacker section.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide an image forming apparatus having a built-in paper transport device that can temporarily accumulate paper that has passed through a fixing device in a stacker and guide it to an image transfer section again. In the present invention, it is an object of the present invention to provide an image forming apparatus in which a path for transporting a paper conveying device to a stacker is simplified, cost is reduced, and jam handling is improved.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for transporting paper to a fixing device via an image transfer section formed between an image bearing member and a transfer device. An image forming apparatus having a built-in paper conveying device that can temporarily accumulate the sheets of paper that has passed through the fixing device in a stacker below the path and guide the sheets to the image transfer section again, the image forming device having a built-in paper conveyance device that can temporarily collect the sheets that have passed through the fixing device in a stacker and guide them to the image transfer section again. A suction-type conveyance means for conveying the paper by attracting it to the surface of the conveyor belt is disposed between the paper conveyance device and the paper conveyance device, and the suction-type conveyance means also serves as a part of the conveyance path of the paper conveyance device to the stacker. be.

Further, the suction type conveyance means is made movable.

(Function) That is, in the present invention, a suction type conveying means is arranged between the image transfer section and the fixing device to convey the paper by attracting it to the surface of the conveyor belt, and the suction type conveyance means is used to transfer the paper to the stacker of the paper conveyance device. Since it is configured so that a part of the carry-in path of the paper conveyance device is also used, part of the pair of guide plates and the pair of conveyance rollers are no longer required, which simplifies the path of carry-in to the stacker of the paper conveyance device, reducing costs and saving space. Due to this increase, it becomes possible to improve the jam handling performance, and it is also possible to cool down the paper that has been heated by the fixing device for sucking and conveying the paper, thereby making it possible to perform good image processing.

Furthermore, since the suction type conveyance means is configured to be movable, the top of the stacker can be opened by retracting the suction type conveyance means, making it possible to more easily remove sheets jammed in the stacker.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the external appearance of the image forming apparatus with the platen cover opened, and FIG. 3A shows the internal structure of the entire apparatus. 1 in the figure is charging, exposure, development, and transfer.

This is an apparatus main body that incorporates image forming process constituent means 2 such as cleaning and fixing, and a paper transport device (ADD) 3. On the top surface of this apparatus main body 1, a document tray is set on a platen glass 4 serving as a document placement table. A platen cover 5 is provided to hold down the original document. Further, on the front edge of the upper surface of the main body 1, as shown in FIG. 2, an operation panel 9 is arranged, on which a numeric keypad 6, a guide display section 7, a copy key 8, etc. are arranged.

On the right side of the apparatus main body 1, there are a paper feed cassette 15 containing paper P such as plain paper to be supplied to the image forming process configuration means 2, a large capacity paper feeder (LCF) 16, and a manual paper feed table 17. It is installed. Furthermore, a tray 18 is installed on the left side of the apparatus main body 1 to collect sheets P of the fixing flow.

The image forming process configuration means 2 has a configuration as shown in FIG. That is, a drum-shaped photoreceptor 20 serving as an image carrier is arranged approximately in the center of the apparatus main body 1, and a charging device 2 is arranged around the photoreceptor 20 along its rotation direction.
1. The exposure section 22a of the exposure device 22, the developing device 23. Transfer device 24. Peeling device 25. Cleaning devices 26 and the like are sequentially arranged.

Further, inside the main body 1 of the apparatus, paper P1 is automatically fed from the paper feed cassette 15 or the large capacity paper feed device 16.
Alternatively, the paper P manually fed via the manual paper feed table 17 is passed through the image transfer section 30 between the photoreceptor 20 and the transfer device 24, and then passed through the pair of paper ejection rollers 31 provided on the left side of the apparatus main body 1. A paper conveyance path 32 is formed that leads to.

A pair of registration rollers 33 is arranged on the upstream side of the image transfer section 30 of the paper transport path 32, and a fixing device 34 is arranged on the downstream side. Further, an image transfer section 30 and a fixing device 3
A suction-type conveying means 35, which will be described later, is arranged between the fixing device 34 and the paper ejection roller pair 31, and a conveying roller pair 36. and gate 3 as a means of distribution
7 are arranged.

Further, in the vicinity of the installed portion of the paper feed cassette 15, there is a take-out roller 40 that is attached to a swingable arm and takes out the sheets P one by one, and a take-out roller 40 that receives the sheets P taken out through the take-out roller 40. Separation and conveyance means 41 consisting of a conveyance roller and a separation roller that feeds the paper into the first branch conveyance path 32a forming the upstream side of the paper conveyance path 32 is provided. Also, in the vicinity of the large-capacity paper feeder 16, there is a take-out roller 42 that is attached to a swingable arm and takes out sheets of paper P one by one; Separation and conveyance means 43 consisting of a conveyance roller and a separation roller that feeds into the second branch conveyance path 32b forming the upstream side of the conveyance path 32 is provided. Further, in the vicinity of the manual paper feed tray 17, a third branch conveyance path 3 is provided which merges the manually fed paper P with the second branch conveyance path 32b.
A pair of manual feed rollers 44 for feeding the paper into the paper 2c is provided.

Further, as shown in FIG. 3A, the exposure device 22 has an exposure lamp 46 whose back is surrounded by a reflector 45 and a first mirror 47 mounted on a carriage (not shown), and is mounted along the lower surface of the document table 3. In the figure, the first optical means 48 moves from the left side to the right side at a speed V, and the second optical means 48 moves from the left side to the right side in the figure. Third
The second optical means 51 includes a mirror 49° 50 mounted on a carriage (not shown) and moves in the same direction at a speed of V/2 in synchronization with the first optical means 48.
a moving optical system that irradiates light onto an original set on a document tray and guides the reflected light to a lens 52; and a fourth. Fifth. and a fixed optical system consisting of a sixth mirror 53, 54, and 55.

Further, the developing device 23 includes an upper developing unit 23a for color development and a lower unit 23b for black development, and can selectively develop black or other colors such as red. Further, the fixing device 34 is configured to include a heating roller 34a containing a built-in heater lamp and a pressure roller 34b that rolls into contact with the heating roller 34a.

Note that the charging device 21. Exposure device 22. Developing device 23
．． Transfer device 24. Peeling device 25. Since the cleaning device 26 and the like have well-known configurations, detailed explanations thereof will be omitted.

Note that a cooling fan 56 is disposed above the paper ejection roller pair 31 in the apparatus main body 1.

Further, the image forming apparatus configured as described above is divided into an upper unit IA and a lower unit IB with the paper transport path 32 as the border, and as shown in FIG. 3B, the upper unit IA and the lower unit IB are divided into The unit IA can be opened clockwise in the figure around a pivot point (not shown) as the center of rotation. The upper surface side of the paper conveyance path 32 from the pair of registration rollers 33 to the pair of paper ejection rollers 31 can be opened.

Further, as shown in FIGS. 1 and 4, the suction type conveying means 35 includes a negative pressure chamber 35a having suction holes (not shown) on both upper and lower surfaces, and an inner circumferential surface of the suction type conveying means 35 is in sliding contact with the negative pressure chamber 35a. The conveyor belt 35d includes a perforated conveyor belt 35d stretched across a drive roller 35b and idle rollers 35c. Further, as shown in FIG. 4, a mounting base (not shown) is pivotally supported on the rear end side of the suction type conveyance means 33 via a pivot means 38. The front end side can be lifted upward as shown by the two-dot chain line in FIG. 4, if necessary. Note 3
9 is a fan attached to the negative pressure chamber 35a.

In addition, the drive roller 35b and the idle roller 35c.
Since the supporting means and driving means of .

Further, below the paper conveyance path 32, the fixing chamber 3
The paper transport device (ADD) 3 is provided which can guide the paper P1 that has passed through the image transfer unit 30, that is, the paper P that has undergone single-sided copying, to the image transfer section 30 again for double-sided copying or single-sided multiple copying. This paper conveyance device (ADD) 3 has a configuration as shown in FIG. That is, as shown in FIGS. 3A and 3B, a stacker 61 forming a temporary stacking section 60 for temporarily stacking sheets P, and a stacker 61
A carry-in path 62 that guides the paper P to the paper P in the stacker 61
and a discharge path 63 for feeding the paper to the first branch conveyance path 32a of the paper conveyance path 32.

The carry-in path 62 includes arc-shaped guide plates 64 and 65 disposed below the gate 37, guide plates 66 and 67 provided between the stacker 61 and the fixing device 34, and the suction type conveyance means 33. A guide plate 68 .disposed between the lower surface of the peeling device 25 and the transfer device 24 and the stacker 61 .
69. Further, as shown in FIGS. 1 and 3A, a pair of conveying rollers 72 and 73 are provided at the base end and the terminal end of the carry-in path 62.

Further, the carry-out path 63 is formed on mutually opposing surfaces of the guide plates 77 and 78, and is provided with a pair of conveying rollers 79. Then, the paper P taken out from the stacker 61 is carried out by the paper feed roller 81.

Further, the stacker 61 is provided with a movable stopper 82 (see FIG. 3A) that can automatically move to a predetermined position depending on the paper size, so that sheets can be stacked in the stacker 61 in an orderly manner. There is.

Further, the gate 37 can be switched in a predetermined direction by a gate operating mechanism 85 using a solenoid as a driving source.

Next, a double-sided copying operation on paper P taken out from the large capacity paper feeder 16 will be described with reference to FIGS. 2, 3A, and 5. First, a document tray is set on the platen glass 4 shown in FIGS. 2 and 3A, and then various images such as paper size, number of copies, 1 double-sided copy, color specification, etc. After inputting the forming conditions, the copy key 8 is pressed. As a result, the drum-shaped photoreceptor 2
0 (see FIG. 3A) rotates in the direction of the arrow (clockwise), and the photoreceptor 20 is uniformly charged by the charging device 21. On the other hand, an original set on the platen glass 4 is scanned by the exposure device 22, and the photoreceptor 20 is exposed to slit light. Then, an electrostatic latent image corresponding to the original is formed on the photoreceptor 20.

The electrostatic latent image on the photoreceptor 20 is transferred to the upper developing unit 23a of the developing device 23 based on the color designation from the operation panel 9.
Alternatively, it is developed and visualized by the lower developing unit 23b.

On the other hand, in synchronization with this developer image forming operation, FIG. 5(a)
The paper P is automatically taken out from the large-capacity paper feeder 16 as shown in FIG. At this time, the movable stopper 82 of the stacker 61 has been moved to a predetermined position in response to the paper size designation signal. The paper P automatically taken out from the large-capacity paper feeder 16 is sent to the image transfer section 30 via a pair of registration rollers 33 as shown in FIG. The developer image is transferred to the paper P by the action of the transfer device 24, and then the paper P is peeled off from the photoreceptor 20 by the peeling device 25 and transferred to the suction conveyance means 3.
5 and is adsorbed and conveyed to the fixing device 34 side.

Next, as shown in FIG. 5(c), the developer image is sent to the fixing device 34, where the developer image is melted and fixed on the paper P, and then
The paper is guided to the paper transport device 3 side by the gate 37 .

After the developer image is transferred onto the paper P, the photoreceptor 20 faces the cleaning device 26 to clean the remaining developer (residual toner) and return to a normal state in which the next copying operation can be performed. .

On the other hand, the paper P guided to the paper transport device 3 side is
As shown sequentially in FIG. 5(d) and FIG. 5(e), the materials are conveyed through the carry-in path 62, are carried into the temporary stacking section 60 of the stacker 61, and are stacked as shown by the two-dot chain line in FIG. 5(e). Then, as shown in FIG. 5(f), when a predetermined number of sheets P on which one-sided copying has been completed is accumulated in the temporary accumulation section 60, a message to replace the original is displayed on the guide display section 7. Next, when you replace the original and press the copy key 8, the photoconductor 20
As the image forming operation is performed for the image shown in FIG. 5(g)
As shown in FIG.
The paper P is taken out and sent to the image transfer section 30 via a pair of transport rollers 79 and a pair of registration rollers 33.

Next, as shown in FIG. 5(h), the developer image is transferred to the paper P in the same manner as described above, and the paper P, on which double-sided copying has been made, is peeled off from the photoreceptor 20, and then transferred through the paper transport path 32. After the developer image is fed into the fixing device 34 and melted and fixed on the paper P as shown in FIG. 5(i), it is guided to the paper ejection roller pair 31 side by the gate 37 and is then deposited as shown in FIG. 5(j). It is guided to tray 18 as shown. This operation is performed by the stacker 61
This continues until the paper P inside is used up.

FIG. 6 shows the state of transporting the paper P after one-sided copying, and FIG. 6(a) shows the state in which the paper P is sucked on the upper surface side of the suction type transport means 35 and sent to the fixing device 34 side. Further, FIG. 6(b) shows a state in which the fixed paper is sent into the carry-in path 62 through the gate 37. Further, FIGS. 6(c) and 6(d) sequentially show the state in which the paper P is sucked on the lower surface side of the suction type conveyance means 35 and sent to the stacker 61 side. Note that the paper P is
By adsorbing and conveying the paper P, the paper P heated by the fixing device 34 can be forcibly cooled, and good double-sided copying is possible without adversely affecting the photoreceptor 20 and the like, which dislike heat.

Note that image formation is performed in the same manner when the paper P is fed from the paper feed cassette 15 or the paper P is fed from the manual paper feed tray 17. In addition, in the case of single-sided copying, the paper can be directly transferred to the tray without being guided to the paper conveying device 3.
It will be discharged on 8th.

Further, as shown in FIG. 3B, the upper unit IA is
If necessary, by opening clockwise in the figure, the upper surface side of the paper transport path 32 from the pair of registration rollers 33 to the pair of paper ejection rollers 31 is opened, and the paper P jammed in this area can be removed or maintained. Inspections, etc. will be carried out. Also,
Figure 3B.

As shown in FIGS. 7 and 8, the suction type conveying means 35
By lifting and rotating the front end of the paper P that is jammed between the guide plates 66 and 67 (see Fig. 3B)
Or the paper P jammed between the guide plates 68 and 69 (
7) or the paper P jammed on the stacker 61 (see FIG. 8) is removed from the top side.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist.

[Effects of the Invention] As described above, according to the present invention, a suction type conveying means for conveying the paper by attracting it to the conveyor belt surface is disposed between the image transfer section and the fixing device, and this suction type conveyance means Since the means is configured so that a part of the path of the paper transport device to the stacker is also used, part of the pair of guide plates and the pair of transport rollers are unnecessary, and the path of the transport device of the paper transport device to the stacker can be simplified. As a result, it is possible to reduce costs and improve jam handling efficiency due to an increase in space.Furthermore, it is possible to cool down the paper that has been heated by the fixing device for sucking and conveying the paper, making it possible to perform good image processing.

Furthermore, since the suction type conveyance means is configured to be movable, the upper part of the stacker can be opened by retracting the suction type conveyance means, and the paper jammed in the stacker can be more easily removed.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic perspective view showing the main components of a paper conveying device, which is the main part;
FIG. 2 is an external perspective view of the image forming apparatus with the platen cover open, FIG. 3 A is a schematic vertical cross-sectional front view of the entire image forming apparatus, and FIG. 3 B is a schematic vertical cross-sectional view of the image forming apparatus with the upper unit open. A front view, FIG. 4 is a schematic perspective view showing the configuration of the suction type conveyance means, FIG. 5 is an explanatory diagram showing the operating state during double-sided copying, and FIG. 6 is an illustration showing the paper conveying state during double-sided copying. 7 and 8 are explanatory diagrams each showing a state in which the suction type conveyance means is displaced to perform jam removal. 3...Paper transport device (ADD), 20...Image carrier (photoreceptor), 24...Transfer device, 30...Image transfer section, 32...Paper transport path, 33... Registration roller pair, 34...Fixing device, 35...Adsorption type conveyance means,
35d...Transport belt, P...Paper.

Claims (2)

[Claims] (1) The paper that has passed through the fixing device is temporarily stacked in a stacker below the paper conveyance path that passes through the image transfer section formed between the image carrier and the transfer device and reaches the fixing device, and is transferred to the image transfer section again. An image forming apparatus having a built-in paper conveying device that can be guided, wherein an adsorption type conveying means for conveying the paper by attracting it to a conveying belt surface is disposed between an image transfer section and a fixing device in a paper conveying path, An image forming apparatus characterized in that the suction type conveyance means also serves as a part of the conveyance path of the paper conveyance device to the stacker. (2) The image forming apparatus according to claim 1, wherein the suction type conveying means is movable.