JPH1048898A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a device small in size and minimum in installation space and to facilitate jamming treatment by arranging plural image forming units in a vertical direction in space located at the upper part of a paper supply cassette. SOLUTION: An image forming part 8 is provided in the space located at the upper part of a paper supply cassette attaching part 4. In the image forming part 8, the image forming units 9a to 9d for forming the image of respective color components such as black, yellow, magenta and cyan are arranged in the vertical direction in order from the upside. A paper carrying means 26 carrying paper housed in the paper supply cassette 3 to the respective photoreceptor drums 13a to 13d of the image forming part 8 is provided on the left side of the image forming part 8. The paper carrying means 26 is provided with rotatable carrying rollers 27 and 28 arranged in the vertical direction and a carrying belt 29 stretched over the rollers, carrying the paper to the drum 13a to 13d and being in press-contact with the drums 13a to 13d through the paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus for transferring an image of each color component onto a sheet in a superposed manner.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer for performing full-color printing and a copying machine for performing full-color copying, a so-called tandem system is provided with a plurality of image forming units corresponding to respective color components. For example, in a laser printer that performs full-color printing, four color components of yellow, cyan, magenta, and black are used.
One image forming unit is provided.

Each image forming unit includes a photosensitive drum on which an electrostatic latent image is formed on the surface, a developing device for visualizing the electrostatic latent image formed on the surface of the photosensitive drum as a toner image of each color component, A laser light source that irradiates a laser beam according to image information, a polygon mirror that deflects the laser beam from the laser light source in the scanning direction, a lens unit that forms a laser beam deflected by the polygon mirror on a photosensitive drum, and the like are provided. ing.

[0004] Around the photosensitive drum, a main charger for charging the photosensitive drum in advance, a transfer unit for transferring the toner image on the photosensitive drum onto paper and separating the paper from the photosensitive drum.
A separation device and the like are arranged. Such image forming units are generally arranged in a horizontal direction in a casing of the image forming apparatus. Paper is sequentially supplied from a paper supply unit such as a paper supply cassette to an image forming unit in which each image forming unit is arranged, and toner images of respective color components are transferred in an overlapping manner. The sheet on which the toner image has been transferred is heated and fixed by a fixing unit provided on the side of the image forming unit, and is discharged to a discharge tray.

[0005]

In such an image forming apparatus, a paper transport path from a paper feed unit such as a paper feed cassette to a paper output tray is horizontally disposed inside the casing, and is thus planar. The size is large and a large installation space is required. Further, when a paper jam occurs in the paper transport path, it is difficult to open the paper transport path, and there is a problem that the jam processing is structurally difficult.

[0006] Further, since the polygon mirror is usually installed so that the rotation axis is in the vertical direction, in order to form the laser beam deflected by the polygon mirror on the surface of the photosensitive drum, the beam must be vertically oriented. A mirror for deflecting light is required. Therefore, such an image forming apparatus has a problem that the structure of each image forming unit is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus which is small in size, can minimize the installation space, and can easily perform jam processing.

[0008]

An image forming apparatus according to the present invention comprises a casing, a sheet cassette, an image forming section,
Paper transport means. The sheet cassette accommodates sheets in a stacked state, and is mounted on the lower end inside the casing. In the image forming unit, a plurality of image forming units corresponding to each color component are vertically arranged in a space located above a sheet cassette inside the casing. The paper transporting means is provided in the vertical direction for sequentially transporting the paper stored in the paper feed cassette to each image forming portion of the plurality of image forming units. Thus, the plurality of image forming units are compactly arranged on the upper portion of the paper feed cassette, the size can be reduced, and the installation space can be reduced.

Further, since the paper conveying means is provided in the vertical direction, the jam clearance when a paper jam occurs is simplified. In particular, when the sheet conveying means is provided close to one side surface of the casing and an opening means for opening the sheet conveying means to the side is further provided, the jam clearance is further simplified. Further, a fixing device for heating and fixing the image transferred on the sheet may be configured to extend above the sheet conveying means. Further, it is possible to further provide a paper discharge unit that is disposed in a space above the image forming unit and located on a side of the fixing device and discharges paper from the fixing device. In this case, without increasing the size of the image forming apparatus,
A fixing device and a paper discharge unit can be arranged.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus to which an embodiment of the present invention is applied will be described with reference to the drawings. FIG.
FIG. 2 is a schematic cross-sectional configuration diagram of a printer that performs full-color printing. The printer body 1 has a casing 2. At the lower end of the casing 2, a paper feed cassette mounting section 4 for mounting the paper feed cassette 3 is provided. The paper feed cassette 3 stores paper therein, and has one end supported on the inner bottom surface and the other end movable vertically.
have. The upper mounting plate 5 is urged upward by a spring 6.

A paper feed roller 7 is arranged above the paper feed cassette mounting section 4 and at a position where it comes into contact with one end of the paper stored in the paper feed cassette 3. The paper stored in the paper feed cassette 3 is placed on the upper mounting plate 5 in a stacked state. One end of the paper is pushed upward by a spring 6 and the uppermost paper is pressed against the paper feed roller 7. Have been.

An image forming section 8 is provided in a space located above the sheet cassette mounting section 4. In the image forming section 8, for example, image forming units 9a, 9b, 9c, 9d for forming images of respective color components of black, yellow, magenta, and cyan from the top are vertically arranged. The image forming units 9a to 9b are each shown in FIG.
As shown in FIG. 1, a photosensitive drum 13 on which an electrostatic latent image is formed, a developing unit 14 for forming a toner image of each color component on the photosensitive drum 13, and a laser beam on the photosensitive drum 13 And a laser scan unit 15 for condensing light to form an electrostatic latent image. Around the photosensitive drum 13, a main charger 16 for charging the peripheral surface of the photosensitive drum 13 in advance, and a transfer roller 1 for transferring a toner image on the photosensitive drum 13 onto a conveyed sheet.
7 and a cleaning device 18 for removing the toner remaining on the peripheral surface of the photosensitive drum 13.

The developing unit 14 is provided with a toner cartridge 19 containing color toners corresponding to the respective color components. The toner cartridge 19 is in contact with a feed roller 20 for feeding the toner and a peripheral surface of the photosensitive drum 13. Developing roller 21 and developing roller 2 for forming a toner image on photosensitive drum 13
A developer replenishing roller 22 for supplying toner to the peripheral surface of the developing roller 1 is provided.

The laser scan unit 15 includes a laser light source (not shown) for irradiating a laser beam corresponding to image information, a polygon mirror 24 which is driven to rotate by a motor 23 and deflects the laser beam from the laser light source, and a polygon mirror 24. A lens unit 2 for forming an image of the deflected laser beam on the peripheral surface of the photosensitive drum 13
5 are provided.

In the image forming section 8, image forming units 9a to 9d as shown in FIG. 2 are vertically arranged, and the photosensitive drums 13a and 13a are located on the left side of the image forming section 8 in FIG.
3b, 13c, and 13d are located in order from the top. The left side of the image forming unit 8 in FIG.
Paper transport means 26 for transporting to 3a, 13b, 13c, 13d is provided. The sheet conveying means 26 includes conveying rollers 27 and 28 which are arranged vertically and rotatable, and
The photosensitive drum 1 is stretched over the two transport rollers 27 and 28.
The transport belt 29 transports the paper to 3a to 13d and presses the photosensitive drums 13a to 13d through the paper.
And

Each photosensitive drum 1 is transported via a transport belt 29.
Transfer rollers 17a, 17b, 17c, 17d are provided at positions facing 3a, 13b, 13c, 13d, respectively. The sheet conveying means 26 is provided near one side surface (left side in FIG. 1) of the casing 2. 1 is provided on the left side surface of the casing 2 in FIG. The lower end of the open panel 30 is rotatably supported on a concentric axis with the rotation axis of the transport roller 28. The above-described paper transport means 26 is fixed to the open panel 30 and can be opened sideways integrally with the open panel 30.

Below the open panel 30, there is provided a manual tray 10 which can be opened and closed laterally. Open panel 3
When the manual feed tray 10 is opened to the side in a state in which the manual feed tray
From 0, paper can be supplied to the paper transport means 26. A fixing device 31 for heating and fixing the toner image formed on the sheet is provided above the sheet conveying means 26. The fixing device 31 includes a heating roller 32 having a heater therein, a pair of pressure rollers 33 and 34, and a fixing belt 35 formed of an endless metal belt stretched between the heating roller 32 and one of the pressure rollers 33. And

On the right side of FIG. 1 of the fixing device 31, there is provided a discharge port 36 for discharging a sheet. Further, in a space located above the image forming unit 8, a paper discharge tray 37 for receiving paper discharged from the discharge port 36 is provided. Driving means (not shown) is provided for each of the paper feed roller 7, the paper transport means 26, the photosensitive drum 13, and the fixing device 31, and is provided from the paper feed cassette 3 or the manual tray 10 via the image forming unit 8 and the fixing device 31. The paper is conveyed to the paper discharge tray 37 through the tray.

This image forming apparatus includes a control unit 41 as shown in FIG. The control unit 41 is a CPU, RO
It is constituted by a so-called microcomputer system including M, RAM, various IOs and the like. An image information input unit 42 for receiving image information from a data processing device such as a computer, a word processor, an image scanner, and an OCR is connected to the control unit 41. Further, the control unit 41 includes:
An image processing unit 43 that separates the input image information into color components and converts the image information into image information for each color component is connected. Further, the image forming unit 8 is connected to the control unit 41. The control unit 41 drives each laser light source of the image forming unit 8 based on the image information converted for each color component by the image processing unit 43, and places a static image based on the color component on each of the photosensitive drums 13a to 13d. An electrostatic latent image is formed, and a toner image based on each color component is formed. Further, the control unit 41 is connected to a paper transport system 44 including the paper feed roller 7, the paper transport unit 26, and the like, and the fixing device 31.

In the image forming apparatus according to this embodiment, the sheet cassette 3 containing the sheets is mounted on the sheet cassette mounting section 4. At this time, the uppermost sheet in the sheet cassette 3 is in contact with the sheet feed roller 7 by the action of the spring 6. When there is a print processing instruction, the paper feed roller 7 is driven to feed the topmost sheet to the sheet conveying means 26, or the sheet placed on the manual feed tray 10 is sent to the sheet conveying means 26. Then, the sheet conveying means 26 is driven to convey the sheet to the photosensitive drum 13 of the image forming section 8. At the same time, the laser light sources of the image forming units 9a to 9d are driven based on the image information of each color component,
a to 13d to form electrostatic latent images. Each photosensitive drum 1
The electrostatic latent images on 3a to 13d are visualized as toner images by the respective color toners by the developing roller 21.

The paper transported by the transport belt 29 is in contact with each of the photosensitive drums 13a to 13d, and is charged from the back surface by the transfer rollers 17a to 17d via the transport belt 29, whereby each color component is The toner images are sequentially transferred in the order of cyan, magenta, yellow, and black. The sheet conveyed by the sheet conveying means 26 is further conveyed to the fixing device 31. In the fixing device 31, the fixing belt 35 heated by the heating roller 32 is used.
Are rotated between the pressure roller pairs 33 and 34 in a pressure-contact state. A toner image transferred by the image forming unit 8 is formed on the paper conveyed between the pair of pressure rollers 33 and 34, and the toner image is heated and melted by the heat of the fixing belt 35 and fixed. . After this, the paper is output to the paper output tray 37.
Is discharged.

In this embodiment, the image forming units 9a to 9d for each color component are vertically arranged in a space located above the paper feed cassette 3, and the installation space is substantially the same as the planar shape of the paper feed cassette 3. It can be of the order of magnitude. In addition, the sheet transporting means 26 can be opened integrally with the opening panel 30 provided on the side of the casing 2, so that the jam clearance when a paper jam occurs can be easily performed.

Further, in each of the image forming units 9a to 9d, the laser beam deflected by the polygon mirror 24 can be condensed in the horizontal direction as it is to form an image on the photosensitive drum 13, so that the laser beam is folded back. Mirrors and the like can be omitted, the apparatus can be simplified, and downsizing and cost reduction can be achieved. Further, the paper discharged onto the paper discharge tray 37 is in a so-called face-down state in which the surface on which the image is formed faces downward, and handling after execution when printing a plurality of pages becomes easy.

[Other Embodiments] It is also possible to apply the present invention to a copying machine having an image reading unit such as a scanner on the upper surface.

[0025]

In the image forming apparatus according to the present invention, an image forming section in which a plurality of image forming units corresponding to respective color components are arranged in a vertical direction is arranged in a space located above a sheet feeding cassette. In addition, the installation space of the apparatus can be configured to be approximately the same size as the planar shape of the paper feed cassette, so that downsizing and space saving can be achieved.

Further, since the paper transport means for transporting the paper from the paper feed cassette to the image forming section is provided in the vertical direction, the jam clearance when a paper jam occurs becomes easy.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional configuration diagram of an image forming apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of an image forming unit.

FIG. 3 is a control block diagram schematically illustrating an image forming apparatus to which an embodiment of the present invention is applied.

[Explanation of symbols]

 Reference Signs List 2 Casing 3 Paper feed cassette 4 Paper feed cassette mounting section 7 Paper feed roller 8 Image forming section 9a to 9d Image forming unit 13a to 13d Photoconductor drum 14 Developing section 15 Laser scan unit 16 Main charger 17 Transfer roller 18 Cleaning device 21 Developing roller 24 Polygon mirror 25 Lens unit 26 Paper transport means 29 Transport belt 30 Open panel 31 Fixing device 37 Paper ejection tray

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Uehira, 1-2-28 Tamazo, Chuo-ku, Osaka-shi Inside Mita Kogyo Co., Ltd. (72) Kuniaki Nakano 1-2-28, Tamazo, Chuo-ku, Osaka-shi No. Mita Kogyo Co., Ltd. (72) Inventor Kiyotaka Arai 1-2-2 Tamazo, Chuo-ku, Osaka City Mita Kogyo Co., Ltd.

Claims (4)

[Claims] 1. An image forming apparatus for superimposing and transferring images of respective color components on a sheet, comprising: a casing; a sheet cassette in which the sheets are stored in a stacked state, and which is mounted on a lower end portion inside the casing; An image forming unit in which a plurality of image forming units corresponding to respective color components are vertically arranged in a space located above the paper feed cassette inside the casing; and sheets stored in the paper feed cassette And a sheet conveying means provided in a vertical direction for sequentially conveying the image to each image forming portion of the plurality of image forming units. 2. The apparatus according to claim 1, wherein said sheet conveying means is provided near one side of said casing, and opening means for opening said sheet conveying means to the side is provided on one side of said casing. 2. The image forming apparatus according to 1. 3. The image forming apparatus according to claim 1, wherein a fixing device that heats and fixes the image transferred onto the sheet extends above the sheet conveying means. 4. The image forming apparatus according to claim 3, further comprising a sheet discharge unit disposed in a space above the image forming unit and beside the fixing device and configured to discharge a sheet from the fixing device. Image forming apparatus.