JPH04256643A - 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]

0001

[Field of Industrial Application] The present invention relates to image forming apparatuses such as copying machines, printers, facsimile machines, etc., and more particularly, the present invention relates to image forming apparatuses such as copying machines, printers, and facsimile machines. The present invention relates to an image forming apparatus having a conveyance path leading to a forming section.

0002

2. Description of the Related Art In image forming apparatuses such as copying machines, printers, and facsimile machines, small-sized image forming apparatuses generally use
A configuration as shown in FIG. 7 is adopted. That is, a paper feed cassette 2 is arranged at the bottom of the apparatus main body 1, and a photosensitive drum 3, a primary charger 5, a developing device 6, a cleaning device 7, a transfer charger 9, a fixing device 10, etc. are arranged in the middle section above it. Further, an optical system 11 for forming an image of the original onto the photosensitive drum 3 is disposed in the upper part.

In such an image forming apparatus, due to the arrangement of the paper feed cassette 2 and the transfer device 9 which is the image forming section, the conveyance direction of the sheet material is approximately opposite between the paper feed section and the image forming section. Therefore, a conveyance path 13 is provided which changes the direction of the sheet material fed from the paper feed cassette 2 in a substantially U-shaped curved path 12 in a direction substantially opposite to the paper feeding direction and guides it to the image forming section.

However, since the curved path 12 of this conveyance path 13 has a relatively small curvature, when a thick sheet material such as a business card passes through this curved path 12, wrinkles, curls, etc. occur. This may cause image blur or jams.

Furthermore, since small-sized sheet materials pass through the curved path 12, there are many intermediate rollers (not shown) in the curved path 12.
This may complicate the structure, or the leading edge of the sheet material may get caught in the gap between each intermediate roller and the guide plate, causing a jam.

For this reason, in a small-sized image forming apparatus having the above-mentioned transport path 13, when feeding small-sized or thick sheet materials, conventionally, the paper feeding cassette 2 disposed at the bottom of the apparatus main body 1 is used. A method is adopted in which the sheet material is fed from a paper feed port 15 provided on the side surface of the apparatus main body 1 without passing through the curved path 12.

[0007]

[Problems to be Solved by the Invention] However, in the case of the above-mentioned conventional method of feeding sheet materials from the paper feed port 15 provided on the side of the apparatus main body 1, A space L is required to feed new paper (on the side opposite to the paper ejection side), which increases the area occupied by the device, and even though it is miniaturized, the installation space is also limited. there were.

[0008]Furthermore, in some conventional cases, the paper feed port 15 is provided with a tray 17 for holding and guiding the sheet material S, but this tray 17 has a small number of sheets to be loaded in order to simplify the device. However, there is also the problem that it is inconvenient to form images on a large number of sheets at once.

The present invention was developed in view of the above-mentioned circumstances, and it is possible to prevent small-sized or thick sheet materials from getting caught, wrinkled, etc. without increasing the area occupied by the main body of the device.
It is an object of the present invention to provide an image forming apparatus that allows smooth conveyance without curling or the like.

0010

[Means for Solving the Problems] The present invention, for example, as shown with reference to FIGS. 1 and 2, a fed sheet material (Sa)
The present invention relates to an image forming apparatus having a conveying path (13) that changes the sheet feeding direction in a curved path (12) in a direction substantially opposite to the sheet feeding direction and leads the sheet to an image forming section (9).

[0011] In order to achieve the above object, the present invention moves the fed sheet material (Sb) along the curved path (12).
an evacuation path (35) that can be guided to the image forming section (9) without passing through the evacuation path (35); and a sheet that detects that the fed sheet material (Sb) has been sent into the evacuation path (35). a detection means (41); and an external selection means (46) for conveying the fed sheet material (Sb) to the image forming section (9) via the evacuation path (35), By inputting the external selection means (46), the fed sheet material (S
b) is sent to the evacuation path (35), the evacuation path (35)
The sheet material (Sb) in 5) is connected to the sheet detecting means (41
) from the evacuation path (35) after detection by the image forming unit (
9).

0012

[Operation] According to the above structure, the fed sheet material (Sa) is normally conveyed to the image forming section (9) via the curved path (12). Then, when the external selection means (46) is input, the fed sheet material (Sb) is conveyed to the image forming section (9) via the evacuation path (35) that avoids the curved path (12).

[0013] As a result, the sheet material (
No problem will arise if Sa) is transported via the evacuation path (35). Further, since the evacuation path (35) is provided in the conveyance path (13) using idle space within the apparatus main body (1), the area occupied by the apparatus main body (1) does not become large.

[0014] The above reference numerals in parentheses are used to refer to the drawings and do not limit the structure in any way.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

First Embodiment FIG. 1 shows the overall configuration of an image forming apparatus (copying machine) according to a first embodiment of the present invention.

In the present image forming apparatus, the same members as those in the image forming apparatus shown in the conventional example will be described with the same reference numerals.

In this image forming apparatus, the optical system 11 disposed below the document table 19 includes movable reflection mirrors 20, 2.
1, a lens 22, fixed reflection mirrors 23, 25, etc. The original image placed on the original platen 19 is captured by a movable reflection mirror 20 that moves together with the illumination lamp 26, and a movable reflection mirror that moves in the same direction at a moving speed of 1/2 of this movable reflection mirror 20. While the optical path length is kept equal by 21, the light is further formed into an image on the photosensitive drum 3 via a lens 22 and fixed reflection mirrors 23 and 25. The surface of the photosensitive drum 3 is made of a photosensitive member with a photosensitive layer covered with a transparent insulating layer, and when it is charged by the primary charger 5 and reaches the exposure section 26, it is charged by the above-mentioned optical system 11 onto the original platen 1.
The upper original image is formed.

The electrostatic latent image formed on the surface of the photosensitive drum 3 is visualized by the developing device 6, and the toner image is transferred to the transfer section (
In the image forming section), the transfer charger 9 transfers the image onto the sheet material S fed from the paper feeding section. After the transfer, the sheet material S is led to the fixing device 10 by the conveyor belt 27, where it is fixed by pressure, heat, etc., and is discharged to the paper discharge tray 16 outside the machine. Note that after the transfer to the sheet material S, residual toner adhering to the surface of the photosensitive drum 3 is removed by a cleaning device 7 in preparation for the next cycle.

Normally, the sheet materials S are loaded in the paper feed cassette 2, and are fed from the paper feed cassette 2 when the copy start switch is turned on. When the copy start switch is turned on, the paper feed roller 30 rotates counterclockwise to separate the sheet materials S in the paper feed cassette 2 one by one and feed them to the curved path 12 of the conveyance path 13. The sheet material S sent out to the curved path 12 is sent to a pair of registration rollers 32 by a pair of conveyance rollers 31. The sheet material S is synchronized with the movement of the optical system 11 by the registration roller pair 32, and is sent between the photosensitive drum 3 and the transfer charger 9, where the original image is transferred as described above. Ru.

In this image forming apparatus, in the case of small-sized sheets or thick sheets such as postcards and business cards, the sheet material S is transferred while avoiding the curved path 12, without using the above-mentioned paper feeding method. A paper feeding method is used that leads the paper to the section. This paper feeding method is
The sheet material S is fed from the paper feed tray 33 installed above the paper feed cassette 2, and the evacuation is provided in a gentle curve extending above the apparatus main body 1 near the downstream end of the curved path 12. This is achieved by guiding the paper to the retracting path 35 and further guiding it from the evacuation path 35 to the transfer section.

The sheet material S placed on the paper feed tray 33 is fed by a pair of paper feed rollers 36, and further by a pair of transport rollers 3.
7, 39 to the evacuation path 35. The sheet material S sent to the evacuation path 35 is guided to the registration roller pair 32 by a pair of conveying rollers 39 that rotate in the opposite direction. Note that the sheet material S is inserted through a paper feed port 49 having a tray 47 and placed on the paper feed tray 33.

At the base of the evacuation path 35, there is a pair of registration rollers 32 for guiding the sheet material S fed from the paper feed tray 33 to the evacuation path 35, and for guiding the sheet material S fed to the evacuation path 35 to the evacuation path 35.
A switching lever 40 is provided to switch the path depending on whether the path is guided to In addition, an optical or mechanical sheet detection sensor 41 for detecting the rear end of the sheet material S fed from the paper feed tray 33 is provided immediately before the pair of conveyance rollers 39 in the evacuation path 35 .

Next, the paper feeding operation of the present image forming apparatus will be explained with reference to FIG.

In this image forming apparatus, the paper feed cassette 2
When performing normal paper feeding using the main body 1, the copy start switch 43 of the operation section (keyboard) 42 of the main body 1 of the apparatus is turned on. In this way, the microcomputer (
A copy start instruction is issued from the MPU (MPU) 45, whereby the paper feed roller 30, the pair of transport rollers 31, and the pair of registration rollers 32 are driven to rotate in the direction of the arrow, and the switching lever 40 is switched to the imaginary line position. Therefore, paper cassette 2
The inner sheet material Sa is guided to the transfer section via the curved path 12 as described above.

On the other hand, when feeding a small-sized, thick sheet material Sb using the paper feed tray 33, the operating section 42
Press the paper type designation key (external selection means) 46, and then turn on the copy start switch 43. In this way, the microcomputer 45 instructs to start copying, which causes the pair of paper feed rollers 36, the pair of transport rollers 37 and 39, and the pair of registration rollers 32 to rotate in the direction of the arrow, and the switching lever 40 to the solid line position. Can be switched. Therefore, the sheet material Sb on the paper feed tray 33 is sent to the evacuation path 35 through the upper surface of the switching lever 40. At this time,
When the sheet detection sensor 41 detects the rear end of the sheet material Sa, based on this, the rotation of the conveying roller pair 39 is stopped and the switching lever 40 is switched to the imaginary line position. After that, the conveyance roller pair 39 rotates in the opposite direction, and the sheet material Sb
registration roller pair 32 via the top surface of the switching lever 40.
lead to. Then, when the sheet material Sb passes the switching lever 40, the switching lever 40 is switched to the solid line position again.

Note that when the paper type specification key 46 is pressed,
The paper feed roller 30 and the transport roller pair 31 do not rotate.

Second Embodiment FIG. 3 shows the overall configuration of an image forming apparatus (copying machine) according to a second embodiment of the present invention.

This embodiment shows a case in which the escape path 51 is located above the switching lever 50 provided near the downstream end of the curved path 12.

The switching lever 50 can be switched between a solid line position and an imaginary line position, and a pair of conveying rollers 52 is provided approximately at the center thereof. This switching lever 50 is used to switch the sheet material S loaded in the paper feed cassette 2.
When feeding paper a, the position is switched to the imaginary line position, and the sheet material Sa sent out by the paper feed roller 30 downstream of the curved path 12 forms a conveyance path up to the registration roller pair 32. Further, when the switching lever 50 feeds the sheet material Sb of small size etc. stacked on the paper feed tray 33, it is first switched to the solid line position, and the sheet material Sb is moved to the evacuation path 51 on the switching lever 50. , the switching lever 50 is switched to the imaginary line position.

In the case of this image forming apparatus, when the copy start switch 43 is turned on, the paper feed roller 30, the pair of transport rollers 52, and the pair of registration rollers 32 are rotated, and the switching lever 50 is switched to the imaginary line position. by this,
The sheet material Sa in the paper feed cassette 2 is guided to the transfer section via the curved path 12.

Further, when the paper type designation key 46 is pressed and the copy start switch 43 is turned on, the transport roller pair 36
, 52, the registration roller pair 32 is rotationally driven, and the switching lever 50 is switched to the solid line position. As a result, the sheet material Sb on the paper feed tray 33 is sent to the evacuation path 51 on the switching lever 50. At this time, the sheet detection sensor 41
detects the rear end of the sheet material Sb, based on this, the conveying roller pair 52 stops rotating and the switching lever 50
is switched to the imaginary line position. Thereafter, the conveyance roller pair 52 reversely rotates to transfer the sheet material Sb to the registration roller pair 32.
lead to.

In the case of this embodiment, the evacuation path 51 is the curved path 12.
Since it is located inside the main body 1, the device main body 1 can be made smaller than in the first embodiment.

Third Embodiment FIG. 4 shows the overall configuration of an image forming apparatus (copying machine) according to a third embodiment of the present invention.

While the second embodiment uses the paper feed tray 33, this embodiment uses a paper feed cassette 55 that is fed by a paper feed roller 53 so that a large number of copies can be made continuously. This shows the case where it is used.

<Fourth Embodiment> FIG. 5 shows the overall configuration of an image forming apparatus (copying machine) according to a fourth embodiment of the present invention.

This embodiment shows an example of a structure in which the structure of the first embodiment is partially changed so that small-sized sheets and thick sheets can also be fed by the paper feed cassette 2. It is.

That is, a passage 56 is provided that connects the middle of the curved passage 12 and the forward side of the switching lever 40 of the evacuation passage 35.
A switching lever 57 is attached to the branch part on the curved path 12 side of 6.

In this image forming apparatus, the paper feed cassette 2
When feeding normal sheet material Sa from the switching lever 5
7 to the imaginary line position to close the passage 56. In this way, the sheet material Sa fed from the paper feed cassette 2 is sent to the transfer section via the curved path 12.

Furthermore, when feeding small size or thick sheet material Sb from the paper feed cassette 2, the switching lever 40,
57 to the solid line position to keep the passage 56 and the evacuation path 35 open. In this way, the sheet material Sb fed from the paper feed cassette 2 is sent to the evacuation path 35 via the path 56. Thereafter, the same operation as described in the first embodiment is performed, and the sheet material Sb is guided to the registration roller pair 32.

<Fifth Embodiment> FIG. 6 shows the overall configuration of an image forming apparatus (copying machine) according to a fifth embodiment of the present invention.

In this embodiment, a paper feed tray 33 is added to the configuration of the fourth embodiment, and a small size or thick sheet material Sb
This figure shows an example of a configuration in which paper can also be fed from this paper feed tray 33.

When feeding the sheet material Sb from the paper feeding tray 33, the same operation as when feeding the sheet material Sb from the paper feeding cassette 2 is performed.

[0044] In FIGS. 5 and 6, reference numerals 59, 60, 6
Reference numerals 1 and 62 denote a pair of conveying rollers.

[0045]

Effects of the Invention As described above, the image forming apparatus of the present invention has a retreat path that can guide the fed sheet material to the image forming section without passing through a curved part, and a a sheet detecting means for detecting that the sheet material has been sent into the evacuation path; and an external selection means for transporting the fed sheet material to the image forming section via the evacuation path; When the fed sheet material is sent to the evacuation path by the input of the selection means, the sheet material in the evacuation path is guided from the evacuation path to the image forming section after being detected by the sheet detection means. It is characterized by this.

[0046] Therefore, it is possible to smoothly convey small-sized or thick sheet materials without causing snags, wrinkles, curls, etc., without increasing the area occupied by the apparatus main body.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (copying machine) according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a paper feeding operation of the image forming apparatus.

FIG. 3 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (copying machine) according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (copying machine) according to a third embodiment of the present invention.

FIG. 5 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (copying machine) according to a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (copying machine) according to a fifth embodiment of the present invention.

FIG. 7 is a longitudinal sectional side view showing the overall configuration of a conventional image forming apparatus (copying machine).

[Explanation of symbols]

9 Transfer charger (image forming section) 12
Curved path 13 Conveyance path 35, 51 Retraction path 41 Sheet detection sensor 46 Paper type specification key (external selection means) Sa,
Sb sheet material

Claims (1)

[Claims] Claims: 1. In an image forming apparatus having a conveyance path that changes a fed sheet material in a direction substantially opposite to the paper feeding direction on a curved path and guides the fed sheet material to an image forming section, the fed sheet material is guided along the curved path. an evacuation path capable of guiding the fed sheet material to the image forming section without passing through the evacuation path; a sheet detection means for detecting that the fed sheet material is sent into the evacuation path; external selection means for transporting the sheet material to the image forming section via the evacuation path, and when the fed sheet material is sent to the evacuation path by input from the external selection means, The image forming apparatus is characterized in that the sheet material is guided from the evacuation path to the image forming section after being detected by the sheet detecting means.