JP2011065069A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact image forming apparatus. <P>SOLUTION: The image forming apparatus (a laser printer 1) includes: an image forming part 4; a placing part (a paper feed tray 31) disposed below the image forming part 4 to place a recording medium; a feeding part (a feed roller 32A) for turning back the record medium placed on the placing part and carrying the same toward the image forming part 4; a first carrying path 32B inclined downward from the feeding part; and a second carrying path 23 formed successively from the first carrying path 32B and inclined upward from the connecting part 23A with the first carrying path 32B toward a fixing part (a fixing device 43). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium such as paper.

  2. Description of the Related Art Conventionally, as an image forming apparatus, an image forming apparatus is known in which a paper feed tray that accommodates paper is disposed so as to protrude forward from the front panel of the apparatus main body (see Patent Document 1).

JP 2001-103217 A

  However, the conventional technique has a problem in that the apparatus is enlarged in the front-rear direction because the paper feed tray projects toward the front side from the front panel. On the other hand, the structure in which the paper feed tray is arranged at the lower part of the apparatus main body can suppress the enlargement of the apparatus main body in the front-rear direction, but there is a problem that the apparatus main body is enlarged in the vertical direction.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can be downsized.

  In order to solve the above-described problems, an image forming apparatus according to the present invention is sensitive to a developer container that contains a developer, and the developer in the developer container is supplied to an electrostatic latent image on a photoreceptor. A developing unit that forms a developer image on the body, a transfer unit that transfers the developer image on the photoreceptor onto a recording medium, and a fixing unit that thermally fixes the recording medium onto which the developer image is transferred. An image forming unit, a placement unit disposed below the image forming unit, on which a recording medium is placed, and a feeding unit that folds the recording medium placed on the placement unit and conveys the recording medium toward the image forming unit An output part, a first conveyance path inclined obliquely downward from the supply part, and the first conveyance path are formed continuously from the continuous part to the first conveyance path toward the fixing part. And a second conveyance path inclined obliquely upward.

  According to the present invention, by placing the mounting unit below the image forming unit, it is not necessary to project the mounting unit from the side surface of the apparatus main body, and the apparatus main body can be downsized in the lateral direction. Further, since the first conveying path is inclined obliquely downward, each component such as the developer accommodating portion can be lowered, and the apparatus main body can be downsized in the vertical direction.

  According to the present invention, it is possible to reduce the size of the apparatus main body.

It is sectional drawing which shows the laser printer which concerns on one Embodiment of this invention. FIG. 4 is a cross-sectional view illustrating a state where a front cover is opened and a toner cartridge is taken out.

Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
In the following description, the direction will be described with reference to the user when using the laser printer. That is, in FIG. 1, the right side toward the paper surface is “front side (front side)”, the left side toward the paper surface is “rear side (back side)”, the back side toward the paper surface is “right side”, and the paper surface is facing. Let the near side be the “left side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the laser printer 1 includes an apparatus main body 2, a feeder unit 3, an image forming unit 4, and the like.

  The apparatus main body 2 is formed in a hollow case shape, and an opening 2A is formed on the front wall thereof, and a front cover 21 that opens and closes the opening 2A is provided so as to be swingable back and forth ( (See FIG. 2). The front cover 21 is formed with a manual feed opening 21A so as to face a first conveyance path 32B described later. Further, the upper surface of the apparatus main body 2 serves as a paper discharge tray 22 on which paper P as an example of a printed recording medium is placed.

  The feeder unit 3 includes a paper feed tray 31 as an example of a placement unit and a paper supply mechanism 32.

  The paper feed tray 31 is a tray for stacking and placing the sheets P, and is disposed below the image forming unit 4 (lower part of the apparatus main body 2). In the paper feed tray 31, a pressing plate 31A that presses the front end of the paper P toward a paper feed roller 32A described later is provided.

  The paper supply mechanism 32 is disposed on the upper front side of the paper feed tray 31, and mainly includes a paper feed roller 32A as an example of a feeding unit, a first transport path 32B, a transport roller 32C, and a registration roller 32D. I have.

  The paper feed roller 32A is a roller that folds the paper P placed in the paper feed tray 31 into a U-shape and conveys it toward the image forming unit 4, and has a relatively large diameter in order to fold back the paper P well. It is formed with.

  The first conveyance path 32B is configured by a plurality of guides G and the like, and is formed so as to be inclined obliquely downward and rearward from the upper part of the paper feed roller 32A. Further, the second transport path 23 is formed continuously at the rear end portion of the first transport path 32B.

  The second transport path 23 is configured by a guide G, a process cartridge 42, which will be described later, and the like, and obliquely rearward and upward from a continuous portion 23A with the first transport path 32B toward a fixing device 43 as an example of a fixing section described later. It is formed so as to be inclined.

  The transport rollers 32C are a pair of rollers that sandwich and transport the paper P, and are provided in the first transport path 32B. More specifically, the transport roller 32C is disposed away from the V-shaped continuous portion 23A on the upstream side in the transport direction by a distance shorter than the entire length of the paper P (length in the transport direction). Thereby, when the leading edge of the paper P reaches the continuous portion 23A, the transporting force can be applied to the paper P by the transport roller 32C, so that the leading edge of the paper P is prevented from being caught by the continuous portion 23A.

  Further, the conveyance roller 32 </ b> C is disposed away from the manual feed opening 21 </ b> A formed in the front cover 21 by a distance shorter than the total length of the paper P. This ensures that the user can insert the paper P into the apparatus main body 2 from the manual feed opening 21 </ b> A, that is, in a state where a part of the paper P protrudes out of the apparatus main body 2, so Therefore, the conveyance roller 32C can be used as a manual feed roller.

  The registration rollers 32 </ b> D are a pair of rollers for aligning the leading end position of the paper P, and are provided in the second conveyance path 23. Specifically, the registration roller 32D is disposed at a position slightly away from the continuous portion 23A on the downstream side in the transport direction.

  In the feeder unit 3 configured as described above, the paper P in the paper feed tray 31 is folded by the paper feed roller 32A and then conveyed to the registration roller 32D by the conveyance roller 32C. Thereafter, the paper P is transported to the image forming unit 4 with its leading end position aligned by the registration rollers 32D.

  The image forming unit 4 includes a scanner unit 41, a process cartridge 42, a fixing device 43, and the like.

  The scanner unit 41 has a known structure including a laser light emitting unit, a polygon mirror, and the like, and scans the laser beam on the surface of the photosensitive drum 51 of the process cartridge 42 at a high speed.

  The process cartridge 42 includes a drum cartridge 5, a developing device 6 as an example of a developing unit, and a toner cartridge 7 as an example of a developer storage unit.

  The drum cartridge 5 includes a photosensitive drum 51 as an example of a photosensitive member, a transfer roller 52 as an example of a transfer unit, a scorotron charger 53, and the like.

  The developing device 6 includes a developing roller 61, a layer thickness regulating blade 62, a supply roller 63, and the like, and is attachable to and detachable from the drum cartridge 5.

  The toner cartridge 7 is a container that contains toner as an example of a developer therein, and is detachable from the developing device 6.

  The toner cartridge 7 is disposed along the first conveyance path 32B. Thereby, there is no useless space between the toner cartridge 7 and the first transport path 32B, and the apparatus main body 2 is downsized. Further, the toner cartridge 7 is disposed so as to be adjacent to the continuous portion 23A, that is, disposed so as to approach the second transport path 23 rising from the first transport path 32B. Therefore, there is no useless space between the toner cartridge 7 and the second transport path 23, and the apparatus main body 2 is further downsized.

  Further, the developing device 6 is disposed above the toner cartridge 7 and at a position adjacent to the second transport path 23. As a result, as shown in FIG. 2, the connecting portion 7A of the toner cartridge 7 with the developing device 6 (the surface on which the supply port and the like are formed) can be directed upward, so that toner leakage from the connecting portion 7A is suppressed. It is possible. Further, by making the developing device 6 adjacent to the second transport path 23, there is no useless space between the developing device 6 and the second transport path 23, and the apparatus main body 2 is further reduced in size.

  The drum cartridge 5, the developing device 6 and the toner cartridge 7 described above can be attached to and detached from the apparatus main body 2 through an opening 2A which is opened by opening the front cover 21, as shown in FIG. ing.

  In the process cartridge 42 configured as described above, as shown in FIG. 1, the toner fed into the developing device 6 from the toner cartridge 7 is supplied to the developing roller 61 by the supply roller 63. At this time, the supply roller The frictional charge is positive between 63 and the developing roller 61. The toner supplied onto the developing roller 61 enters between the layer thickness regulating blade 62 and the developing roller 61 as the developing roller 61 rotates, and is carried on the developing roller 61 as a thin layer having a constant thickness. The

  On the other hand, in the drum cartridge 5, the surface of the photosensitive drum 51 is uniformly positively charged by the scorotron charger 53 and then exposed by high-speed scanning of the laser beam from the scanner unit 41. Thereby, the potential of the exposed part is lowered, and an electrostatic latent image based on the image data is formed. Next, when the developing roller 61 rotates, the toner carried on the developing roller 61 is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 51 when it contacts the photosensitive drum 51. The

  Thus, the toner is selectively carried on the surface of the photosensitive drum 51 to be visualized, and a toner image is formed by reversal development. Thereafter, when the paper P is conveyed between the photosensitive drum 51 and the transfer roller 52, the toner image carried on the surface of the photosensitive drum 51 is transferred onto the paper P.

  The fixing device 43 includes a heating roller 43A and a pressure roller 43B. In the fixing device 43, the toner image transferred onto the paper P is thermally fixed while the paper P passes between the heating roller 43A and the pressure roller 43B. The paper P thermally fixed by the fixing device 43 is discharged onto the paper discharge tray 22 by a paper discharge roller 44 disposed on the downstream side of the fixing device 43 in the transport direction.

  A third conveyance path 24 for double-sided printing is provided on the rear side of the fixing device 43 and the process cartridge 42. The third transport path 24 extends rearward and downward from the downstream side in the transport direction of the fixing device 43 (specifically, between the fixing device 43 and the paper discharge roller 44), and the second transport path 24 is upstream of the registration roller 32D in the transport direction. It is formed so as to join the path 23. Accordingly, it is possible to form a conveyance path for double-sided printing without increasing the size of the apparatus main body 2 up and down, compared to a mode in which the third conveyance path is merged with the first conveyance path 32B.

  The third transport path 24 is provided with a plurality of pairs of return rollers 24A that transport the paper P while pinching it. Specifically, among the plurality of pairs of return rollers 24A, the upstream three pairs of return rollers 24A are more than the full length of the sheet P from the obtuse angle bending portion 24B that bends at an obtuse angle of 90 ° or more in the third transport path 24. A short distance is arranged away from the upstream side in the transport direction. Thereby, when the leading edge of the paper P reaches the obtuse angle bent portion 24B, a conveying force can be applied to the paper P by the return roller 24A. Yes.

  Further, the pair of return rollers 24A located on the most downstream side is disposed in the vicinity of the apex of the acute angle bent portion 24C that bends at an acute angle of less than 90 ° in the third transport path 24. As a result, even if the leading edge of the paper P is likely to be jammed by abutting against the acute angle bent portion 24C, the leading edge of the paper P is forcibly conveyed by being sandwiched between the pair of return rollers 24A at the apex of the acute angle bent portion 24C. Further, it is possible to suppress the jamming of the paper P.

According to the above, the following effects can be obtained in the present embodiment.
By setting the paper feed tray 31 below the image forming unit 4, it is not necessary to project the paper feed tray 31 from the side surface of the apparatus main body 2, and the apparatus main body 2 can be downsized in the lateral direction. Further, since the first conveyance path 32B is inclined obliquely downward, each component such as the toner cartridge 7 can be lowered, and the apparatus main body 2 can be downsized in the vertical direction.

  Since the registration roller 32D is provided in the second conveyance path 23, the continuous portion 23A between the first conveyance path 32B and the second conveyance path 23 is aligned after aligning the tip position as compared with the structure in which the registration roller is provided in the first conveyance path. Since there is no need to pass the paper P through the (bent portion), the paper P with the leading end position aligned can be reliably sent to the image forming unit 4. Further, by providing the registration roller 32D in the second conveyance path 23, a portion of the second conveyance path 23 between the registration roller 32D and the continuous portion 23A can be exposed to the side opposite to the first conveyance path 32B. Therefore, the third conveyance path 24 for double-sided printing can be easily joined to the second conveyance path 23.

  Since the transport roller 32C is provided in the first transport path 32B, it is possible to prevent the leading edge of the paper P from being caught by the continuous portion 23A (bent portion) between the first transport path 32B and the second transport path 23. The transport roller 32C can also be used as a paper feed roller that feeds the paper P inserted from the manual feed opening 21A.

  Since the toner cartridge 7 is arranged along the first conveyance path 32B, there is no useless space between the toner cartridge 7 and the first conveyance path 32B, and the apparatus main body 2 can be downsized.

  Since the toner cartridge 7 is disposed so as to be adjacent to the continuous portion 23A, there is no useless space between the toner cartridge 7 and the second transport path 23, and the apparatus main body 2 can be further reduced in size.

  By disposing the developing device 6 above the toner cartridge 7, the connecting portion 7A of the toner cartridge 7 with the developing device 6 (the surface on which the supply port and the like are formed) can be directed upward. Toner leakage can be suppressed. Further, by making the developing device 6 adjacent to the second transport path 23, there is no useless space between the developing device 6 and the second transport path 23, so that the apparatus main body 2 can be further reduced in size. .

  The third conveyance path 24 for duplex printing is formed so as to extend from the downstream side in the conveyance direction of the fixing device 43 and join the second conveyance path 23 on the upstream side in the conveyance direction of the registration roller 32D. The apparatus main body 2 can be reduced in size up and down as compared with a mode in which the conveyance path passes below the continuous portion 23A and merges with the first conveyance path 32B.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, each of the developing unit and the developer accommodating unit is configured with two parts (the developing device 6 and the toner cartridge 7). However, the present invention is not limited to this, and the developing unit and the developer accommodating unit are configured as one component. You may comprise integrally.

In the embodiment, the paper P such as a thick paper, a postcard, and a thin paper is adopted as an example of the recording medium. However, the present invention is not limited to this, and may be an OHP sheet, for example.
In the above-described embodiment, the photosensitive drum 51 is employed as the photosensitive member. However, the present invention is not limited to this, and for example, a belt-shaped photosensitive member may be employed.

In the above-described embodiment, the transfer roller 52 is used as the transfer unit. However, the present invention is not limited to this, and a transfer roller that does not have a roller shape may be used.
In the above-described embodiment, the fixing unit having the heating roller 43A is used. However, the present invention is not limited to this. For example, a fixing unit that uses a cylindrical fixing film that is slidably supported by a guide is used. May be.

  In the above-described embodiment, the paper feed tray 31 that can be pulled out of the apparatus main body 2 is used as the placement section. However, the present invention is not limited to this, and for example, a recess formed integrally with the apparatus main body 2 is used as the placement section. It may be adopted.

  In the above-described embodiment, the paper feed roller 32A is used as the feeding unit. However, the present invention is not limited to this. For example, a guide that is curved to fold back a sheet and a plurality of rollers provided along the guide. May be configured.

  In the above embodiment, the present invention is applied to the laser printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Apparatus main body 4 Image formation part 6 Developing apparatus 7 Toner cartridge 23 2nd conveyance path 23A Continuous part 24 3rd conveyance path 31 Paper feed tray 32A Paper feed roller 32B 1st conveyance path 32C Conveyance roller 32D Registration roller 43 Fixing Device 51 Photosensitive drum 52 Transfer roller P Paper

Claims (7)

A developer accommodating portion that accommodates the developer, a developing portion that forms a developer image on the photoreceptor by supplying the developer in the developer accommodating portion to the electrostatic latent image on the photoreceptor, and the photoreceptor. An image forming unit having a transfer unit that transfers the developer image on the recording medium and a fixing unit that thermally fixes the recording medium to which the developer image is transferred;
A placement unit disposed below the image forming unit for placing a recording medium;
A feeding unit that folds the recording medium placed on the placing unit and conveys the recording medium toward the image forming unit;
A first conveyance path inclined obliquely downward from the feeding section;
An image forming apparatus comprising: a second conveyance path formed continuously with the first conveyance path and inclined obliquely upward from the continuous portion with the first conveyance path toward the fixing unit. .   The image forming apparatus according to claim 1, wherein a registration roller for aligning a leading end position of the recording medium is provided in the second conveyance path.   The image forming apparatus according to claim 1, wherein a transport roller for transporting the recording medium is provided in the first transport path.   The image forming apparatus according to claim 1, wherein the developer accommodating portion is disposed along the first conveyance path.   The image forming apparatus according to claim 4, wherein the developer accommodating portion is disposed adjacent to the continuous portion.   The image forming apparatus according to claim 5, wherein the developing unit is disposed above the developer containing unit and adjacent to the second transport path. A third conveyance path for double-sided printing;
The third conveyance path is formed so as to extend from the downstream side in the conveyance direction of the fixing unit and to join the second conveyance path on the upstream side in the conveyance direction of the registration roller. The image forming apparatus according to claim 6.

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