JP2003091112A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which is provided with a by-pass paper feeding part capable of feeding special paper and whose installation area can do with the minimum size. SOLUTION: Paper including the special paper is stored at a stack by-pass 20 and supplied to an image forming part 16 thereby, and its length in a paper feeding direction is shorter than those of paper feeding cassettes 18 and 19. A by-pass carrying path 42 is arranged between a longitudinal carrying path 41 and the stack by-pass 20. The paper is carried upward from the stack by-pass 20 while it is smoothly bent so as to join the longitudinal carrying path 41. At least, an original platen 15, an optical system 21, the paper feeding cassettes 18, 19, an ejected paper tray 57 and the stack by-pass 20 are arranged in an up-and-down direction at a position where they are nearly superposed in plan view at the inside of a main body 10.

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 provided with a bypass paper feeding section for supplying so-called material paper such as thick paper, OHP sheet and surface coated paper to the image forming section. .

[0002]

2. Description of the Related Art Image forming apparatuses such as copying machines, printers, and facsimile machines are desired to be downsized in order to save space in an office. For example, in a copying machine, a plurality of paper feed cassettes storing paper are prepared according to the size of the paper used, and each paper feed cassette is detachable from the apparatus. Also, on the top of the copier,
A document table on which a document is placed is provided. The paper placed on the platen is irradiated with light, and the light reflected from the document is converted into an electrical signal by a CCD sensor or the like, and the CCD is used.
An electrostatic latent image is formed on the surface of the photosensitive drum based on a signal from the sensor, and the electrostatic latent image is visualized as a toner image by a developing device. After that, the paper on which the toner image is formed is conveyed to the fixing device, and the toner image is heated and fused and fixed.

Papers for forming images include B5 and B
Sizes such as 4, A4, and A3 are common, and the size of the document table is often adjusted to A3 so that the largest A3 size document can be placed. Further, in many cases, the paper feed cassette mounting portion in which the paper feed cassette is detachable can mount a paper feed cassette capable of storing A3 size paper.

The paper pulled out from the paper feed cassette mounting portion is conveyed to the image forming portion via the paper feed conveying path, and the paper on which the toner image is transferred on the surface of the image forming portion passes through the paper discharging conveying passage. And is conveyed to the fixing device and discharged to the paper discharge tray. Here, the document table and the paper feed cassette mounting portion are arranged vertically so as to overlap each other in a plan view, and the paper feed conveyance path, the image forming portion, and the paper discharge conveyance are arranged so that the paper conveyance direction is the vertical direction. By devising the arrangement of the path and the fixing device, it is possible to provide a copying machine having an installation area slightly larger than the A3 size.

In this case, the sheet pulled out from the sheet feeding cassette is abruptly changed in direction and conveyed in a sheet feeding conveying path extending in the vertical direction. For this reason, cardboard, OHP sheets,
It is difficult to store special paper such as surface-coated paper, so-called material paper, in such a paper feed cassette for use. Therefore, there is one in which a bypass tray that can store the material paper is provided and the bypass transport path is configured so that the paper transported from the bypass tray to the image forming unit does not suddenly change direction.

[0006]

In the image forming apparatus as described above, the bypass tray is usually provided so as to project to the side of the apparatus. When using this bypass tray, the paper is placed on the bypass tray protruding to the side of the apparatus, the paper feed position for paper feeding is designated from the operation panel to the bypass tray, and the start button is operated.

Therefore, in such an image forming apparatus, the bypass tray projects to the side of the apparatus body, and the actual installation area becomes larger than the area occupied by the apparatus body by the amount of the bypass tray. An object of the present invention is to provide an image forming apparatus that includes a bypass paper feed unit that can feed material paper (special paper) such as thick paper, OHP sheet, and surface coated paper, and that can minimize the installation area. To provide.

[0008]

An image forming apparatus according to a first aspect of the present invention is a document table, a document reading section, an image forming section, a fixing device, a paper discharge tray, a paper feed cassette, a paper feed cassette mounting section,
It is provided with a paper feed unit, a bypass paper feed unit, and a casing that internally houses each unit. The original is placed on the upper surface of the original table.
The document reading unit irradiates a document placed on a document table with light and detects the reflected light to read a document image. The image forming unit develops a document image read by the document reading unit into a toner image and transfers the toner image onto a sheet. The fixing device heats and melts and fixes the toner image formed on the paper in the image forming unit. The paper discharge tray is provided above the fixing device and discharges the paper. The paper feed cassette accommodates paper in order to supply the paper to the image forming unit. The paper feed cassette mounting portion can mount a paper feed cassette. The paper feeding unit supplies the paper to the image forming unit. The bypass paper feed unit accommodates paper including special paper, can feed the paper to the image forming unit, and has a shorter length in the paper feed direction than the paper feed cassette. Further, the paper feeding unit is arranged between the vertical feeding path for feeding the paper upward from the paper feeding cassette to the image forming unit and between the vertical feeding path and the bypass feeding unit, so that the paper can be smoothly fed from the bypass feeding unit. And a bypass transport path for transporting upward while bending and joining the vertical transport path. Further, at least the document table, the document reading unit, the paper feed cassette mounting unit, the paper discharge tray, and the bypass paper feed unit are vertically arranged in the casing at positions where they are substantially overlapped with each other.

In such an image forming apparatus, its installation area can be made to correspond to the size of the original placed on the original table and the size of the paper stored in the paper feed cassette, which is slightly larger than, for example, A3 size. It can be installed in the occupied area. An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, in which the image forming unit and the fixing device are vertically arranged between the vertical transport path and the paper discharge tray.

An image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the first or second aspect, in which the casing has an opening on the side. The bypass paper feeding unit can be pulled out from the opening in parallel with the paper feeding direction. An image forming apparatus according to a fourth aspect is the image forming apparatus according to the third aspect, further including a lid member that rotatably supports the bypass sheet feeding unit, and a sheet having a size not larger than a prescribed size. The opening can be closed when the is mounted.

[0011]

1 is a vertical sectional view of a copying machine to which an embodiment of the present invention is applied. The copying machine 1 has a main body 10 and a document holder 11 mounted on the top of the main body 10 so as to be openable and closable. A document table 15 on which a document is placed is arranged at the upper part of the main body 10. Inside the main body 10, an image forming unit 16 is provided at an end portion on the left side when viewed from the front and substantially at the center in the vertical direction.
Further, a paper feed unit 17 for feeding a document to the image forming unit 16 is provided in the lower portion.

The paper feed section 17 is detachably attached to the main body 10 and holds paper feed cassettes 18 and 19 for storing paper.
And a stack bypass 20 provided above it. An optical system 21 for reading image information of a document placed on the document table 15 is provided below the document table 15. The optical system 21 includes a light source 22 for irradiating the surface of a document placed on the document table 15 with light, and mirrors 23, 24, 2 for deflecting the light reflected from the surface of the document.
5 and a lens 2 for converging the light from the mirror 25
6 and an image sensor 27 such as a CCD sensor that receives the light converged by the lens 26 and generates an image data signal corresponding to the original image.

The image forming section 16 has a photosensitive drum 30 on the surface of which an electrostatic latent image is formed, and further the photosensitive drum 3
0, the main charging device 31, the developing device 32,
It has a transfer roller 33 and a cleaning device 34. The main charging device 31 is a device for charging the surface of the photoconductor drum 30, and is arranged diagonally above and to the right of the photoconductor drum 30. A photoconductor drum 3 is provided diagonally below the photoconductor drum 30 with a predetermined gap from the main charging device 31.
A developing device 32 for forming a toner image on the image forming apparatus 0 is arranged. The developing device 32 accommodates toner inside and visualizes the electrostatic latent image formed on the photosensitive drum 30 with the toner. The transfer roller 33 is a device for transferring the toner image on the photosensitive drum 30 onto a sheet, and is arranged on the left side of the photosensitive drum 30. The cleaning device 34 is a device for removing the residual toner and the like on the surface of the photoconductor drum 30.
It is located above 0.

A laser unit 35 for forming an electrostatic latent image on the peripheral surface of the photosensitive drum 30 is provided on the right side of the photosensitive drum 30. The laser unit 35 forms an electrostatic latent image on the peripheral surface of the photosensitive drum 30 based on the image data signal obtained from the image sensor 27. The paper feed unit 17 includes a vertical transport path 41 for transporting paper from the paper feed cassettes 18 and 19 toward the image forming unit 16 and a bypass transport path for transporting paper from the stack bypass 20 toward the image forming unit 16. And 42 are provided. Each paper cassette 1
8, 19 and the stack bypass 20 have pickup rollers 43, 4 for taking out the stored sheets.
4, 45 and a pair of paper feed rollers 46, 47, 48 for feeding the sheets one by one to the conveying path. The vertical transport path 41 is provided with the transport roller pairs 49 and 50, and the bypass transport path 42 is provided with the transport roller pair 51. The vertical transport path 41 and the bypass transport path 42 meet below the transfer position where the photosensitive drum 30 and the transfer roller 33 face each other. A registration roller 52 is provided at the merged portion to hold the conveyed sheet at a predetermined position.

Above the photosensitive drum 30 and the transfer roller 33, a fixing device 53 for melting and fixing the toner transferred onto the sheet is provided. The fixing device 53 is
A heating roller 54 having a built-in heater and a pressure roller 55 that comes into pressure contact with the heating roller 54 are provided. The paper is sandwiched between both rollers to be conveyed, and the toner image formed on the surface of the paper is heated and fixed. It is a thing.

Further above the fixing device 53, the branch portion 5 is provided.
6 is provided. On the right side of the branch portion 56, a discharge tray 57 for discharging the paper through a discharge roller pair 60.
Is disposed above the discharge tray 57, and the discharge roller pair 6
1 and a sub-discharge tray 58 from which paper is discharged. A switchback unit 59 for reversing the paper at the time of duplex copying is provided on the lower left side of the branch unit 56.
Are arranged. The branch part 56 is provided with a branch claw 62 for switching the paper transport direction between the discharge tray 57 direction and the switchback part 59 direction. Branch claw 62
Two branch claws 63 and 64 are provided on the left side of the. Below the two branching claws 63 and 64, a switchback conveying path 65 for guiding the sheet to the switchback section 59 is provided.
Is provided, and a sub-tray transport path 66 that guides the sheet to the sub-tray 58 is provided above the finisher. A transport path 67 is provided. The branching claws 63 and 64 are switchable so as to guide the conveyed sheet to either the switchback conveyance path 65, the sub-tray conveyance path 66, or the finisher conveyance path 67. [Stack Bypass] Details of the stack bypass 20 will be described with reference to FIGS. 2 and 3.

The stack bypass 20 has a base 81 and a lid member 82 rotatably supported by the base 81. The base 81 has a mounting plate 86 on which a sheet is mounted.
A pick-up roller 45 that is located above the left end of the placing plate 86 and has a sheet shape for pulling out a sheet.
And a paper feed roller pair 48 for feeding the paper one by one to the transport path. On the left side of the pair of paper feed rollers 48, there is a guide surface 87 for guiding the paper to the bypass conveyance path 42 side.
Is provided. In addition, both sides of the base body 81 (main body 10
In the front-back direction), the guided rail 84 and the guide roller 85
It has guided parts 83 and 83 provided with. Correspondingly, a guide rail 72 having a guide roller 73 for guiding the lower surface of the guided rail 84 is provided inside the main body 10.
Is provided. The base 81 is guided by the guide rail 72 and can be pulled out from the opening 71 provided on the right side of the main body 10.

A guide groove 88 is provided on the placing plate 86, and partition plates 89, 89 which engage with the guide groove 88 and align the sheets in the left-right direction are attached.
Further, the mounting plate 86 is rotatable with respect to the base body 81 via the support shaft 90, and is biased in a direction of pushing up the leading end position of the stored sheets. In this example, a spring 91 is provided on the lower surface of the left end portion of the mounting plate 86, and urges the left end portion of the mounting plate 86 upward.

A cam member 92 is provided on the upper surface of the mounting plate 86.
Are in contact. The cam members 92 are attached to both ends of the rotary shaft of the pickup roller 45, and are in contact with the upper surface of the placing plate 86 at the ends on the downstream side in the paper transport direction. The cam member 92 separates the upper surface of the mounting plate 86 from the pickup roller 45 against the urging force of the spring 91 when not driven. Also, the cam member 9
In No. 2, the cam surface rises with rotation. Along with this, the mounting plate 86 is configured to move to a position where the upper surface of the mounting plate 86 approaches or comes into pressure contact with the pickup roller 45 by the biasing force of the spring 91.

The lid member 82 is rotatably supported at the right end portion of the base body 81, and can close the opening 71 when the base body 81 is stored at a predetermined position in the main body 10. The sheets stored in the stack bypass 20 are
The paper is conveyed to the image forming unit 16 via the bypass conveyance path 42 without suddenly changing its direction. Therefore, the stack bypass 20 is suitable for feeding so-called material paper such as thick paper, OHP sheet, and surface coated paper to the image forming unit 16.

Further, the stack bypass 20 accommodates A4 lateral size paper on a mounting plate 86, and a lid member 82.
Can be closed. Since it is considered that A4 size is often used as the paper size that is normally used, if such a paper is placed on the placing plate 86 and the lid member 82 is closed,
With the paper set in the so-called bypass tray, there is no part that protrudes to the side of the main body 10. Further, since the stack bypass 20 is arranged at a position where it overlaps with the paper feed cassettes 18 and 19, the paper discharge tray 57, the sub tray 58, and the document table 15, the installation area can be minimized.

Further, since the stack bypass 20 can be pulled out from the opening 71 provided on the right side of the main body 10, the work of setting the paper on the placing plate 86 becomes easy, and postcards and the like can be easily set. Even small size paper can be set easily. Stack bypass 2
When 0 is pulled out to the side of the main body 10, the pickup roller 45, the feed roller pair 48, the mechanism for moving the placing plate 86 up and down, etc. are pulled out integrally, so that the positioning accuracy of each mechanism related to paper feeding Will not hurt.

[0023]

According to the image forming apparatus of the present invention, the bypass paper feeding unit can store the paper including the special paper and can supply the paper to the image forming unit. Shorter than the paper cassette, the bypass transport path conveys the paper upward from the bypass paper feed section while smoothly conveying it to join the vertical transport path, and at least the document table, the document reading section, the paper feed cassette mounting section, Since the bypass paper feed unit is arranged in the vertical direction at a position where the bypass paper feed unit almost overlaps in the plan view, the installation area can be reduced and space can be saved.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a copying machine adopting an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part thereof.

FIG. 3 is an exploded perspective view thereof.

[Explanation of symbols]

1 Copier 10 body 15 Platen 16 Image forming section 17 Paper feeder 20 Stack Bypass 21 Optical system 30 photoconductor drum 32 Developing device 33 Transfer roller 42 Bypass transport path 45 Pickup roller 48 paper feed roller pair 71 opening 72 Guide rail 82 Lid member 84 Guided rail 86 mounting plate 91 spring

Continued front page    F term (reference) 2H072 AA32 AB07 BA03 BA12 BA13                       BA17 BA19 CA01 CA02 CB09                 2H171 FA15 FA21 FA22 FA28 GA03                       GA06 HA19 JA13 JA17 JA18                       JA22 QA02 QA08 QC03 SA08                       SA14 SA18 SA19 SA20 SA22                       SA26 SA31 WA02 WA21                 3F343 FA02 FB02 FB03 GA03 GB01                       GC01 GD01 HC04 HC24 HC25                       HC30 HD09 HD15 HD17 JA01                       KB03 KB17 LA04 LA13                 5C062 AA02 AA05 AB08 AB22 AB30                       AB32 AD06 BA01

Claims (4)

[Claims] 1. A document table on which a document is placed, and a document reading section which reads a document image by illuminating a document placed on the document table and detecting reflected light. An image forming unit that develops a document image read by the document reading unit into a toner image and transfers the toner image onto a sheet; and a fixing device that heats and fixes the toner image formed on the sheet by the image forming unit. A paper discharge tray provided above the fixing device to discharge the paper; a paper feed cassette for storing the paper inside to supply the paper to the image forming unit; A paper feed cassette mounting portion, a paper feed portion that feeds paper to the image forming portion, and paper that contains special paper can be stored and can feed paper to the image forming portion. Is shorter than the above paper feed cassette, A casing that accommodates each unit therein is provided, and at least the document table, the document reading unit, the paper feed cassette mounting unit, the paper discharge tray, and the bypass paper feed unit are substantially overlapped in plan view within the casing. And a vertical transport path for transporting a sheet upward from the paper feed cassette to the image forming section, and a vertical transport path between the vertical transport path and the bypass feeding section. An image forming apparatus, comprising: a bypass conveyance path that is arranged and conveys a sheet upward from the bypass sheet feeding unit and joins the vertical conveyance path. 2. The image forming unit and the fixing device are arranged vertically between the vertical transport path and the paper discharge tray.
The image forming apparatus according to claim 1. 3. The image forming apparatus according to claim 1, wherein the casing has an opening on a side thereof, and the bypass sheet feeding section can be pulled out from the opening in parallel with a sheet feeding direction. . 4. The bypass paper feeding unit further has a lid member that is rotatably supported, and is capable of closing the opening when a paper of a prescribed size or smaller is placed.
The image forming apparatus according to item 1.