JP2004029289A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which enables a form to easily and speedily be removed without being torn when the form jams either in a return path or over the return path and an inversion re-conveyance path. <P>SOLUTION: A polarized light converting element is equipped with a paper feed cassette 200, an image forming conveyance path 20, a paper feed conveyance path 22, a reverse conveyance path 24, the return path 26, and the inversion re-conveyance path 28. A bottom wall 50 is arranged in a cassette storage space S, and the inversion re-conveyance path 28 is arranged in the paper feed cassette 200, which is loaded in the storage space S so that it can be drawn out in a paper feed direction. Once the paper feed cassette 200 is loaded, a horizontal area 26c of the return path 26 is formed between the reverse surface of a bottom wall 202 of the paper feed cassette 200 and the top surface of a bottom wall 50 of the storage space S and when the paper feed cassette 200 is drawn out, the horizontal area 26c of the return path 26 is opened. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a laser printer, a facsimile or an electrostatic copying machine, and more specifically, to an image forming apparatus capable of forming an image on both sides of a sheet, which aims at facilitating jam processing and the like. The present invention relates to an image forming apparatus.
[0002]
[Prior art]
One typical example of an image forming apparatus capable of forming an image on both sides of a sheet is an apparatus main body, a paper feed cassette that is detachably mounted on the apparatus main body, and a paper conveyance that is detachably mounted on the apparatus main body. A unit, an image forming transport path on which an image is formed on one side of the sheet to be transported, a sheet transport path for supplying sheets stored in a sheet cassette upstream of the image forming transport path, and an image forming transport A reverse transport path in which the direction of the front and back of the paper selectively introduced from the downstream of the path is reversed and the transport direction is reversed, and the paper reversely transported from the reverse transport path returns to the original state. A return path is provided for returning the sheet, and the sheet returned through the return path is turned upside down again to be re-conveyed upstream of the image forming transport path. The image forming transport path extends in a substantially horizontal direction at a vertically central portion of the apparatus main body. The paper feed cassette is disposed below the image forming transport path, and the paper transport unit is disposed below the paper feed cassette.
[0003]
The reverse transport path includes a region that is inclined and curved downward from the downstream of the image forming transport path and extends downward, a curved region that curves from the downstream end of the downward extending region to the upstream direction of the image forming transport path, and a downstream end of the curved region. And a horizontal retreat area extending substantially horizontally from the image forming conveyance path in the upstream direction. The horizontal retreat area of the reverse transport path is formed between the lower surface of the bottom wall of the sheet transport unit and the upper surface of the bottom wall of the apparatus main body facing the lower surface of the paper sheet with a gap below the lower surface. The return path includes a branch area that branches upward from the upstream end of the curved area of the reverse transport path and extends in a curved manner, and a branch area that extends substantially horizontally from the downstream end of the branch area and upstream of the image forming transport path. And an existing horizontal area. The horizontal area of the return path is disposed in the paper transport unit together with a plurality of pairs of transport rollers. The reverse re-transport path extends substantially vertically at the end of the sheet cassette in the sheet feeding direction. The upstream area in the downwardly extending area, the curved area, and the horizontal retreat area of the reverse transport path, and the upstream area in the branch area and the horizontal area of the reverse transport path are one end of the apparatus main body. Thus, the image forming apparatus is disposed in a housing provided in the apparatus main body so as to protrude outward from one end in the downstream direction of the image forming conveyance path. An opening / closing cover is pivotably disposed on the housing.
[0004]
[Problems to be solved by the invention]
The above-described image forming apparatus can form an image on both sides of a sheet, but has the following problems.
(1) If a paper jam occurs in the reverse transport path and / or the return path, it is necessary to open the cover of the housing and / or pull out the paper transport unit to remove the jammed paper. In particular, when paper is jammed in the horizontal area of the return path provided in the paper transport unit, after pulling out the paper transport unit from the main body of the apparatus, a plurality of pairs manually disposed in the horizontal area of the return path are manually pulled out. It is necessary to remove the sheet by rotating the transport roller and sending the sheet upstream or downstream of the horizontal area of the return path. As a result, a relatively large amount of labor and a relatively long time are required for the jam clearance.
(2) The paper is jammed across the downstream end of the horizontal area of the return path provided in the paper transport unit and the reverse re-transport path extending in the vertical direction provided in the paper feed cassette. In such a case, the paper may be broken when the paper transport unit is pulled out. If the sheet is torn, a part of the sheet may be left in the reversing re-conveying path, making it difficult to clear the jam.
(3) The paper transport unit is provided so as to be able to be pulled out independently of the paper feed cassette with respect to the apparatus main body, and the paper transport unit is provided with a horizontal area of the return path. As a result, the accumulation of component accuracy errors and assembly accuracy errors increases. As a result, when a sheet fed from the sheet cassette and having an image on one side is conveyed in the horizontal area of the return path to apply an image on the other side, the sheet is misaligned in the width direction. Therefore, it is difficult to adjust the positional deviation.
(4) The paper transport unit is provided so as to be able to be pulled out independently of the paper feed cassette with respect to the apparatus main body, and the paper transport unit is provided with a horizontal area of the return path. As a result, the size of the entire image forming apparatus is increased, the configuration is complicated, and the cost is increased.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide an easy-to-use sheet without breaking the sheet in both cases where the paper jam occurs in the return path or when the paper jam occurs across the return path and the reverse re-transport path. It is an object of the present invention to provide a novel image forming apparatus which can quickly remove a sheet.
[0006]
Another object of the present invention is to provide a sheet which is fed from a sheet cassette and has an image on one side conveyed along a return path for applying an image on the other side, and is displaced in the width direction of the sheet. To provide a novel image forming apparatus that can easily and surely prevent the image formation.
[0007]
Still another object of the present invention is to provide a novel image forming apparatus capable of making the whole compact, simplifying the configuration and reducing the cost.
[0008]
[Means for Solving the Problems]
According to the present invention, a sheet feeding cassette which is detachably mounted in a cassette accommodating space provided in an apparatus main body and has a bottom wall, an image forming and conveying path on which an image is formed on one side of a sheet to be conveyed, A paper feed path for supplying the paper accommodated in the paper feed cassette upstream of the image forming transport path, and a reverse transport path in which the transport direction of the paper selectively introduced from the downstream of the image forming transport path is reversed. And a return path in which the sheet reversely transported from the reverse transport path is returned with the same front and back direction, and the sheet returned through the return path is turned upside down and reloaded into the upstream of the image forming transport path. In an image forming apparatus having a reverse re-conveying path,
A bottom wall is provided in the storage space, the reverse re-transport path is provided in an end of the sheet cassette in the sheet feeding direction, and the bottom wall of the sheet cassette is mounted when the sheet cassette is mounted. A part of the return path is formed between the lower surface of the feeder and the upper surface of the bottom wall of the storage space, and the sheet cassette can be pulled out in the downstream direction along the part of the return path. When the paper cassette is pulled out, the partial area of the return path is opened,
An image forming apparatus is provided.
The apparatus main body has a bottom wall, the bottom wall of the accommodation space is constituted by the bottom wall of the apparatus main body, and the image forming / conveying path extends substantially horizontally in a vertical central portion of the apparatus main body. The space is disposed below the image forming conveyance path, and when the sheet cassette is mounted in the storage space, a return path is provided between the lower surface of the bottom wall of the sheet cassette and the upper surface of the bottom wall of the apparatus main body. Is preferably formed.
The reverse transport path includes a curved area that curves upward from the downstream of the image forming transport path, and a vertical retreat area that extends substantially vertically upward from the downstream end of the curved area, and the return path includes the reverse transport path of the reverse transport path. A vertical region that is branched from the downstream end of the curved region and extends substantially vertically downward, a curved region that curves from the downstream end of the vertical region in the upstream direction of the image forming conveyance path, and substantially horizontally and from the downstream end of the curved region. A horizontal region extending in the upstream direction of the image forming conveyance path, wherein a lower surface of the bottom wall of the sheet cassette and an upper surface of the bottom wall of the apparatus main body are formed by mounting the sheet cassette in the accommodation space. It is preferable that the partial area of the return path formed therebetween includes at least the horizontal area of the return path.
The vertical retreat area of the reverse transport path, the vertical area of the return path, and the upstream area of the curved area extend in the vertical direction along the end of the apparatus main body in the downstream direction of the image forming transport path to form an image. In the downstream direction of the transport path, an opening / closing cover is provided at an edge of the apparatus main body, and when the open / close cover is opened, the vertical retreat area of the reverse transport path, the vertical area of the return path, and the upstream area of the curved area are returned. Preferably, it is open.
On the bottom wall of the paper feed cassette, the width direction position of the paper accommodated in the paper feed cassette and the width direction position of the paper conveyed in the partial area of the return path are the same width direction position and the same width. It is preferable that a sheet width direction position restricting means that can be restricted at the same time is provided.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of an image forming apparatus constituted according to the present invention will be described in more detail with reference to the accompanying drawings.
[0010]
Referring to FIG. 1, reference numeral 100 denotes a laser printer (hereinafter simply referred to as “printer”) as an image forming apparatus, and the printer 100 includes a printer main body 102 as a rectangular parallelepiped apparatus main body, and a printer main body 102. A cassette accommodating space S provided in the main body 102, a paper feed cassette 200 removably mounted in the cassette accommodating space S, and a paper transport path including transport paths to be described later are provided. Hereinafter, the configuration of the printer 100 in a state where the sheet cassette 200 is mounted (accommodated) in the cassette accommodation space S of the printer main body 102 will be described. In the following description, in the printer main body 102, the paper feed cassette 200, and the members attached thereto, the width direction indicates the front and back direction of the paper in FIG. 1, the horizontal direction in FIG. 2, and the longitudinal direction. FIG. 1 shows the left-right direction, and FIG. 2 shows the front-back direction of the paper.
[0011]
In the printer main body 102, an image forming means 10 having a well-known configuration is arranged. The image forming unit 10 includes a photoconductor drum 11, a main charger 12, a developing device 13, a transfer roller 14 as a transfer unit, a cleaning device 15, a static eliminator (not shown), and the like arranged around the photoconductor drum 11. An imaging element is provided. The image forming means 10 is also provided at an upper position in the printer main body 102, converts the inputted image information into laser light, and irradiates the surface of the photosensitive drum 11 via the mirror 16 with a laser scanning unit LSU. It has.
[0012]
A paper conveyance path is provided in the printer main body 102. The paper transport path includes an image forming transport path 20 on which an image is formed on one side of the transported paper, and a paper transport path for supplying the paper accommodated in the paper cassette 200 upstream of the image forming transport path 20. 22, a reverse transport path 24 in which the transport direction of a sheet selectively introduced from the downstream of the image forming transport path 20 is reversed, and a sheet reversely transported from the reverse transport path 24 has the front and back sides of the image forming direction. A return path 26 is returned in the transport path 20 in the same state as when an image is formed on one side, and a sheet returned through the return path 26 is turned upside down and reloaded into the upstream of the image formation transport path 20. The image forming apparatus includes a reverse re-conveying path 28 and a discharge path 30 for discharging a sheet selectively introduced from the downstream of the image forming conveying path 20. At the upper end of the printer main body 102, a paper discharge tray 32 for stacking the paper discharged from the discharge path 30 is provided.
[0013]
In this embodiment, the image forming transport path 20 extends substantially horizontally at a substantially central portion in the vertical direction in the printer main body 102. The right side in FIG. 1 of the image forming conveyance path 20 is upstream in the sheet conveyance direction, and the left side in FIG. 1 is downstream in the sheet conveyance direction. The reverse transport path 24 includes a curved area 24a that is curved substantially in an arc shape from the downstream of the image forming transport path 20 upward, and a vertical retreat area 24b that extends substantially vertically upward from the downstream end of the curved area 24a. . The downstream end area, which is the upper end of the vertical retreat area 24b, forms another curved area 24c that is curved substantially in an arc toward the upper side of the paper discharge tray 32, and the downstream end of the other curved area 24c has a discharge end. An opening toward the upper side of the paper tray 32 is formed. The discharge path 30 is curved upward from the downstream side of the image forming transport path 20, further extends substantially vertically inside the reverse transport path 24, and the downstream end area, which is the upper end portion, of the discharge tray 32 It is curved upward. At a downstream end of the discharge path 30, a discharge port for discharging a sheet above the discharge tray 32 is formed. The return path 26 has a vertical area 26a that branches off from the downstream end of the curved area 24a of the reverse rotation transport path 24 and extends substantially vertically downward, and a substantially arc shape in the upstream direction of the image forming transport path 20 from the downstream end of the vertical area 26a. The image forming apparatus includes a curved region 26b that bends, and a horizontal region 26c that extends substantially horizontally from the downstream end of the curved region 26b and upstream in the image forming conveyance path 20. The vertical retreat area 24b of the reverse transport path 24 and the vertical area 26a of the return path 26 are substantially linearly continuous from top to bottom. The reverse re-conveying path 28 includes a vertical region 28a extending substantially vertically, an upstream curved region 28b curved downward from the upstream end of the vertical region 28a toward the upstream, and a downstream region downstream from the downstream end of the vertical region 28a. And a downstream curved region 28c upwardly curved in a substantially arc shape. The upstream end of the upstream curved area 28b of the reverse re-conveying path 28 is continuous with the downstream end of the horizontal area 26c of the return path 26 (the downstream area of the horizontal area 26c is curved upward and downstream). . Further, the downstream end of the downstream curved area 28 c of the reverse re-conveyance path 28 is continuous with the upstream end of the image forming conveyance path 20.
[0014]
In the downstream curved area 28c of the reverse re-transport path 28, a transport roller pair 34 is provided. The transport roller pair 34 includes a large-diameter roller 34a and a small-diameter roller 34b. Part of the peripheral surface of the large-diameter roller 34a forms one surface of the downstream curved region 28c of the reverse re-conveyance path 28. The other surface of the downstream curved area 28c of the reverse re-conveying path 28 is formed by a guide wall provided in the printer main body 102 so as to face the one surface. A pair of registration rollers 36 is disposed downstream of the pair of transport rollers 34 and upstream of the photoconductor drum 11 in the image forming conveyance path 20, and a pair of fixing rollers 38 is disposed downstream of the photoconductor drum 11. Are arranged. The fixing roller pair 38 includes a heating roller 38a and a pressure roller 38b. A transport roller pair 40 is disposed downstream of the fixing roller pair 38 in the image forming transport path 20. At the downstream end of the image forming transport path 20, that is, at the downstream side of the transport roller pair 40, the reverse transport path 24 and the discharge path 30 are branched. A switching claw 42 for switching the transport direction of the sheet is provided at a branch portion between the reverse transport path 24 and the discharge path 30. When the switching claw 42 is switched to the position shown by the solid line in FIG. 1, the paper conveyed through the image forming conveyance path 20 is guided to the reverse rotation conveyance path 24. On the other hand, when the switching claw 42 is switched to the position indicated by the two-dot chain line in FIG. 1, the sheet conveyed through the image forming conveyance path 20 is guided toward the discharge path 30. A discharge roller pair 44 for discharging sheets from the discharge path 30 to the discharge tray 32 is disposed at a discharge port formed at the downstream end of the discharge path 30.
[0015]
At the downstream end of the curved area 24a of the reverse rotation transport path 24, a switching claw 46 for switching the transport direction of the sheet is provided. At the boundary between the downstream end of the curved area 24a of the reverse transport path 24 and the vertical retreat area 24b, a reverse transport roller pair 48 capable of normal and reverse rotation is provided. When the switching claw 46 is switched to the position indicated by the solid line in FIG. 1, the sheet introduced from the image forming conveyance path 20 into the curved area 24 a of the reverse rotation conveyance path 24 moves to the vertical retreat area 24 b of the reverse rotation conveyance path 24. Guided to head. On the other hand, in a state where the switching claw 46 is switched to the position shown by the two-dot chain line in FIG. 1, the sheet introduced into the vertical retreat area 24b of the reverse transport path 24 is returned by the reverse rotation of the reverse transport roller pair 48. Guided to 26.
[0016]
At the edge (left edge in FIG. 1) of the printer main body 102 in the downstream direction of the image forming conveyance path 20, an opening / closing cover 104 has a closed position (the position shown in FIG. 1) around the pivot 106, It is supported rotatably between an open position (not shown). The turning shaft 106 is provided at a lower end portion of the edge of the printer main body 102, and the opening / closing cover 104 has a lower end portion supported by the turning shaft 106 so as to be turnable. Inside the opening / closing cover 104, a driven roller of a reverse transport roller pair 48 composed of a driving roller and a driven roller is supported. The drive roller of the reverse rotation transport roller pair 48 is disposed on the printer main body 102 side. A plurality of ribs are also provided inside the opening / closing cover 104 at intervals in the width direction of the printer main body 102. With the opening / closing cover 104 positioned at the closed position, the driven roller of the reverse rotation transport roller pair 48 is pressed against the drive roller of the reverse rotation transport roller pair 48. Further, the tips of the plurality of ribs disposed inside the opening / closing cover 104 form one surface of the reverse transport path 24, one surface of the vertical area 26a of the return path 26, and one surface of the upstream area of the curved area 26b. With such a configuration, simply turning the opening / closing cover 104 around the turning shaft 106 in the counterclockwise direction in FIG. 1 to open the reverse conveying path 24 and the upstream area of the vertical area 26 a and the curved area 26 b of the return path 26. Are opened to the outside, so that if a paper jam occurs in these transport paths, the jam processing becomes extremely easy. Further, since the reverse transport path 24 and the upstream area of the vertical area 26a and the curved area 26b of the return path 26 extend substantially vertically along the edge of the printer main body 102, the length of the printer main body 102 The length in the direction can be reduced to a minimum. As a result, the entire printer 100 can be made compact, the configuration can be simplified, and the cost can be reduced.
[0017]
Referring to FIGS. 1 and 2, the printer main body 102 includes a bottom wall 50 and side walls 52 on both sides in the width direction of the bottom wall 50 and standing upright on both sides in FIG. (In FIG. 2, only one side wall 52 is shown). Note that, in FIG. 2, the symbol L indicates a vertical line passing through the center of the printer body 102 in the width direction. The center in the width direction of the bottom wall 50 exists on the vertical line L, and the center in the width direction of the sheet cassette 200 described later also substantially exists on the vertical line L. The bottom wall 50 includes a flat plate portion 50a and a plurality of ribs 50b extending upward from the upper surface of the flat plate portion 50a by the same height. Each of the ribs 50b extends over substantially the entire region except for the central region in the longitudinal direction at intervals in the width direction of the flat plate portion 50a. Guide grooves 50c that are open upward are formed on both sides in the width direction of the flat portion 50a of the bottom wall 50. Each of the guide grooves 50c is formed by a concave portion projecting downward so as to have a substantially U-shaped cross section, and extends parallel to each other in the longitudinal direction of the flat plate portion 50a. Each of the guide grooves 50c is provided as a guide means for accommodating a paper feed cassette 200 described later in the cassette accommodating space S of the printer main body 102 and pulling out the cassette from the cassette accommodating space S. It will be described later.
[0018]
On the bottom wall 50, a pair of drive rollers 54a are arranged at intervals in the longitudinal direction. Each pair of drive rollers 54a is disposed at an interval on a shaft 54A, and each of the shafts 54A is rotatably supported between a plurality of ribs 50b disposed near the center in the width direction of the bottom wall 50. , Which are drivingly connected to a driving source which may be an electric motor (not shown). In the flat portion 50a of the bottom wall 50, a concave portion protruding downward is formed in a region facing the drive roller 54a to avoid interference with the drive roller 54a. The cassette accommodating space S is located at the bottom wall 50, both side walls 52, and the end of the printer main body 102, which is located at the downstream end of the image forming / conveying path 20 (the left end in FIG. 1). It consists of a space surrounded by a wall 108 and is disposed below the image forming transport path 20. The bottom wall 50 of the printer main body 102 is also the bottom wall of the cassette housing space S. Therefore, it can be said that the bottom wall of the cassette housing space S is constituted by the bottom wall 50 of the printer main body 102.
[0019]
The paper feed cassette 200 is a box-shaped sheet having a bottom wall 202, side walls 204 provided on both sides in the width direction of the bottom wall 202, and end walls 206 provided on both longitudinal ends of the bottom wall 202. It has a housing. Note that only one of the side walls 204 is shown in FIG. In the paper feed cassette 200, a paper mounting table 208 is provided so as to be pivotable about one longitudinal end (left end in FIG. 1), and the other longitudinal end (right end in FIG. 1) is a compression coil spring. It is urged upward by 210. A pickup roller 212 is provided at an upper position in the printer main body 102 facing the other end of the sheet mounting table 208. Of the sheets P stacked on the sheet mounting table 208, the upper surface of the top end of the sheet P positioned at the highest position has a mutual positional relationship such that the upper surface of the sheet P is pressed against the pickup roller 212 by the spring force of the compression coil spring 210. Have been. The pickup roller 212 is provided on the printer main body 102.
[0020]
A frame 220 is integrally provided outside the end wall 206 on the paper feeding direction side (the right side in FIG. 1) of the paper feeding cassette 200. The frame 220 protrudes outward in the paper feeding direction of the box-shaped paper storage unit. The top end of the frame 220 is higher than the top end of the box-shaped paper storage unit. The lowermost end is formed lower than the lowermost end of the box-shaped paper storage unit. The lowermost end of the frame 220 and the lowermost end of the printer body 102 are positioned on substantially the same plane. The frame 220 includes a paper feed / conveyance wall 222 integrally formed with the end wall 206 so as to extend obliquely upward in the paper feed direction from the upper end of the end wall 206 on the paper feed direction side. The upper surface of the paper feed / conveyance wall 222 has a mutual positional relationship defined so as to face a part of the peripheral surface of the large-diameter roller 34 a in the conveyance roller pair 34 with an interval therebetween. 22 are formed. The paper feed path 22 is provided with a paper feed roller pair 224. The paper feed roller pair 224 is composed of paper feed rollers 224a and 224b that are driven to rotate in the same direction, and one paper feed roller 224a is disposed on the printer main body 102, and the other paper feed roller 224b is supplied with the paper. It is arranged on the frame 220 of the paper cassette 200. The paper feed roller pair 224 functions as a so-called separation roller pair or a separation roller pair.
[0021]
The bottom wall 202 of the sheet cassette 200 includes a plurality of ribs 202a extending downward from the lower surface of the bottom wall 202 by the same height. The ribs 202a are spaced from each other in the width direction of the bottom wall 202 and extend over almost the entire region except the central region in the longitudinal direction. Each of the ribs 202a is positioned so as to oppose each of the ribs 50b disposed on the bottom wall 50 of the printer main body 102 with a gap therebetween, and each of the ribs 202a is provided between each of the ribs 50b. The horizontal area 26c of the return path 26 is configured. The upstream end of the horizontal area 26c curves upward toward the upstream and defines a part of the curved area 26b of the return path 26, and the downstream end of the horizontal area 26c curves upward toward the downstream. are doing. A pair of driven rollers 54b are arranged on the bottom wall 202 at intervals in the longitudinal direction. Each pair of driven rollers 54b is disposed on a shaft 54B, and each of the shafts 54B is rotatably supported between a plurality of ribs 202a disposed near the center in the width direction of the bottom wall 202. Each pair of the driven rollers 54b is pressed against each pair of the driving rollers 54a provided on the bottom wall 50 of the printer main body 102, respectively, and forms a transport roller pair 54 with each pair of the driving rollers 54a. ing.
[0022]
The frame 220 of the sheet cassette 200 is provided with a vertical area 28 a and an upstream curved area 28 b of the reversing re-conveying path 28. The downstream end of the vertical area 28a of the reverse re-conveyance path 28 is continuous with the upstream end of the downstream curved area 28c of the reverse re-conveyance path 28. The downstream end of the paper feed conveyance path 22 joins the continuous portion. are doing.
[0023]
The frame 220 is provided with a horizontal frame 226 including a channel-shaped portion extending in the width direction of the sheet cassette 200 and having a cross section opened downward. The channel-shaped portion of the horizontal frame 226 is A handle 226a for accommodating the paper cassette 200 by being pulled out or pushed in from the cassette accommodating space S is constituted. An operation of pulling out or pushing the paper cassette 200 out of the cassette accommodating space S on both sides in the width direction of the bottom wall 202 of the paper cassette 200 and near the upstream end (the left end in FIG. 1) in the paper feeding direction. A guided plate portion 228 is formed as guided means for guiding the guide plate. Each of the guided plate portions 228 projecting vertically downward from the bottom wall 202 has a substantially triangular shape when the sheet feeding cassette 200 is viewed from the width direction, but has a circular arc shape at its lower end. Each of the guided plate portions 228 thus configured can smoothly and easily slide in the extending direction of the horizontal area 26c of the return path 26 along the guide groove 50c formed in the printer main body 102. Are fitted.
[0024]
At both sides in the width direction at the center portion in the longitudinal direction of the sheet feeding cassette 200, width direction position regulating members 230 constituting width direction position regulating means of the sheet are disposed (in FIGS. 1 and 2, one of the width direction position regulating members). Only the width direction position regulating member 230 is shown). Each of the width-direction position regulating members 230, which can be formed from an appropriate synthetic resin, controls the width direction of the sheet P stored in the sheet cassette 200 and the width of the sheet P conveyed in the horizontal area 26c of the return path 26. The width direction position can be regulated at the same width direction position and the same width at the same time. Although the configuration of each of the width-direction position regulating members 230 and the sheet cassette 200 associated with each of the width-direction restriction members are mutually different in the width direction, they have substantially the same configuration. The configuration of the position regulating member 230 and the configuration of the sheet cassette 200 related thereto will be described.
[0025]
The width direction position regulating member 230 includes a width direction position regulating plate 231 extending in the vertical direction. The width direction position regulating plate 231 has a substantially rectangular shape when the sheet cassette 200 is viewed in the width direction. A rectangular through hole 232 that is elongated in the longitudinal direction is formed at a position near the lower end in the vertical direction of the width direction position regulating plate 231 and in an intermediate region in the longitudinal direction of the sheet cassette 200. The support plate 233, the upper transport guide plate 234, and the lower transport guide plate 235 are integrally formed on the width direction position regulating plate 231. The support plate 233 extends horizontally from the upper edge of the through hole 232 in the width direction position regulating plate 231 to the inside in the width direction of the sheet cassette 200. The upper conveyance guide plate 234 horizontally extends from the lower edge of the through hole 232 in the width direction position regulating plate 231 to the inside in the width direction of the sheet cassette 200. The lower transport guide plate 235 extends horizontally from the width-direction position regulating plate 231 to the inner side in the width direction of the paper feed cassette 200 at a distance below the upper transport guide plate 234, and extends parallel to the upper transport guide plate 234. I have.
[0026]
On the other hand, a pair of guide slots 202A are formed at both sides in the width direction of the bottom wall 202 of the sheet cassette 200 at intervals in the longitudinal direction of the bottom wall 202 and extend in the width direction parallel to each other. I have. The pair of guide elongated holes 202 </ b> A extend from both ends in the width direction of the bottom wall 202 toward the inside in the width direction by a predetermined width and a predetermined length.
[0027]
The width direction position regulating member 230 is formed on one side of the bottom wall 202 of the sheet cassette 200 with the both ends connecting portion 236 sandwiching the through hole 232 in the width direction of the sheet cassette 200 in the width direction position regulating plate 231. By being movably fitted into the pair of guide elongated holes 202 </ b> A, the sheet cassette 200 is supported on one side of the bottom wall 202 so as to be reciprocally movable in the width direction of the sheet cassette 200. The through-hole 232 of the width-direction position regulating plate 231 is fitted into an area 202B existing between a pair of guide elongated holes 202A on one side of the bottom wall 202 of the sheet cassette 200. A predetermined gap is formed between the lower surface of the area 202B of the bottom wall 202 and the lower edge of the through hole 232. The support plate 233 of the width direction position regulating plate 231 is slidably positioned on the upper surface of the bottom wall 202 of the sheet cassette 200. The upper transport guide plate 234 and the lower transport guide plate 235 are positioned below the bottom wall 202. The lower surface of the upper transport guide plate 234 is located slightly above the lower end of the rib 202 a formed on the bottom wall 202 of the paper feed cassette 200, and the upper surface of the lower transport guide plate 235 is located on the bottom wall of the printer main body 102. The rib 50b is formed at the same height as the upper end of the rib 50b.
[0028]
As described above, each of the width-direction position regulating members 230 is slidably mounted in the width direction of the bottom wall 202 at both ends in the width direction of the bottom wall 202 of the paper feed cassette 200. Each of the ribs 202a formed on the bottom wall 202 of the paper feed cassette 200 and the bottom of the printer main body 102 are mounted in a state where each of the width direction position regulating members 230 is mounted on both sides of the bottom wall 202 of the paper feed cassette 200. The horizontal direction of the return path 26 is provided between each of the ribs 50 b formed on the wall 50 and between the lower surface of the upper transport guide plate 234 and the upper surface of the lower transport guide plate 235 in each of the width direction position regulating members 230. A region 26c is formed. The upper region 231a of the width-direction position regulating plate 231 extends upward from the upper surface of the bottom wall 202 in a state where each of the width-direction position regulating members 230 is mounted on both sides of the bottom wall 202 of the sheet cassette 200. By sliding each of the width-direction position regulating members 230 in a direction approaching or separating from each other in the width direction of the bottom wall 202 of the sheet cassette 200, the sheet is placed on the sheet table 208 of the sheet cassette 200. The width direction position of the stacked sheets P is regulated to a predetermined width. Further, the lower region 231b of the width direction position regulating plate 231 extends downward from the lower surface of the bottom wall 202, and allows each of the width direction position regulating members 230 to mutually move in the width direction of the bottom wall 202 of the sheet cassette 200. The sheet P conveyed in the horizontal area 26c of the return path 26 is moved in the width direction of the sheet P stacked on the sheet table 208 of the sheet cassette 200 by sliding the sheet P in the approaching or separating direction. At the same width direction position as the position, the paper P is regulated to the same predetermined width.
[0029]
That is, according to the present invention, the horizontal position 26c which is a partial area of the return path 26 and the position in the width direction of the paper P accommodated in the paper cassette 200 is conveyed to the bottom wall 202 of the paper cassette 200. Since the width direction position regulating means of the paper P, that is, the width direction position regulating member 230, which can simultaneously regulate the width direction position of the paper P at the same width direction position and the same width, is provided, the sheet feeding cassette 200 is provided. When a sheet P fed from the printer and having an image on one side is conveyed through the return path 26 to apply an image on the other side, the sheet P is less likely to be displaced in the width direction. That is, according to the present invention, when the paper P fed from the paper feed cassette 200 and having an image on one side is conveyed along the horizontal area 26c of the return path 26 to apply the image on the other side, the paper P Can be easily and reliably prevented from being displaced in the width direction. Further, the configuration is simple, and it can be put to practical use at low cost.
[0030]
Although not shown, each of the side walls 204 of the sheet cassette 200 is attached to the bottom wall 202 of the sheet cassette 200 so that each of the width-direction position regulating members 230 is attached to the longitudinal direction of the sheet cassette 200. It is formed so as not to exist in the central region. Further, each of the ribs 202a formed on the bottom wall 202 of the paper feed cassette 200 and each of the ribs 50b formed on the bottom wall 50 of the printer main body 102 are connected to each of the width In order to avoid interference with the sliding movement of the cassette 200 in the width direction, the paper feeding cassette 200 is formed so as not to exist in the longitudinal central area on the bottom wall 202 of the paper feed cassette 200 and the longitudinal central area on the bottom wall 50 of the printer main body 102. ing. In FIG. 2, reference numeral 110 denotes a cover that can be opened and closed.
[0031]
Next, a printing operation of the printer 100 configured as described above will be described. Referring to FIG. 1, when a normal single-sided print mode is set, switching claw 42 is positioned at a position indicated by a two-dot chain line. In response to the input of the print start signal, at least the uppermost sheet P among the sheets P stacked on the sheet table 208 of the sheet cassette 200 is sent out by the pickup roller 212 toward the sheet feeding roller pair 224. Only one sheet of the sheet P is sent out toward the sheet feeding conveyance path 22 by the sheet feeding roller pair 224. After the paper P sent out toward the paper feed conveyance path 22 is introduced into the downstream curved area 28 c of the reversing re-conveyance path 28, the conveyance roller pair 34 starts the image formation conveyance path from the upstream end of the image formation conveyance path 20. The sheet is conveyed to the pair of registration rollers 36 through 20 and is stopped once. After a lapse of a predetermined time, the sheet P is passed through the transfer area of the photosensitive drum 11 by the pair of registration rollers 36 and further conveyed toward the pair of fixing rollers 38. While the paper P is conveyed so as to pass through the transfer area of the photosensitive drum 11 and the fixing roller pair 38, an image is formed on one surface thereof in a known manner. The sheet P on which an image is formed on one side is introduced into the discharge path 30 from the downstream end of the image forming and conveying path 20 by the pair of conveying rollers 40, and is discharged onto the discharge tray 32 by the pair of discharge rollers 44.
[0032]
On the other hand, when the normal double-sided print mode is set, the switching claw 42 is switched to the position indicated by the solid line, and the switching claw 46 is positioned at the position indicated by the solid line. The sheet P on which an image is formed on one side as described above is introduced into the curved area 24 a of the reverse rotation conveyance path 24 from the downstream end of the image formation conveyance path 20 by the conveyance roller pair 40. The sheet P introduced into the curved area 24a of the reverse transport path 24 is introduced into the vertical retreat area 24b of the reverse transport path 24 by the reverse transport roller pair 48, and is stopped once after being transported by a predetermined length. At this time, the rear end of the paper P in the transport direction is nipped by the reverse transport roller pair 48, and the front end of the paper P in the transport direction is the downstream end of the vertical retreat area 24b of the reverse transport path 24. From the opening on the paper discharge tray 32. After the switching claw 46 has been switched to the position indicated by the two-dot chain line, the reverse transport roller pair 48 is rotated in the reverse direction. The sheet P is switched back vertically downward toward the return path 26 by the pair of reverse transport rollers 48. The sheet P that has been switched back is introduced into the horizontal area 26c through the vertical area 26a and the curved area 26b of the return path 26. The paper P introduced into the horizontal area 26 c of the return path 26 is turned by each pair of the conveying roller pairs 54 in the same direction as when an image is formed on one side while being conveyed through the image forming conveying path 20. The sheet is conveyed in a state, and is introduced into the reverse re-conveying path 28. The sheet P introduced into the reverse re-conveyance path 28 is turned upside down while being re-conveyed from the reverse re-conveyance path 28 to the upstream end area of the image forming conveyance path 20. The sheet P that has been turned over and re-transported to the image forming transport path 20 is discharged onto the discharge tray 32 after an image is formed on the other side of the sheet as described above. The switching claw 42 is returned to the position indicated by the two-dot chain line before the leading end of the sheet P on which images are formed on both sides is nipped by at least the transport roller pair 40.
[0033]
When a jam of the paper P (that is, a paper jam) occurs in the reverse transport path 24 and the upstream area of the vertical area 26a and the curved area 26b of the return path 26, the opening / closing cover 104 is moved around the pivot 106 in FIG. By simply turning and opening in the counterclockwise direction, these transport paths are all opened to the outside of the printer main body 102, so that the jam clearance can be performed extremely easily and quickly. Further, when the paper P is jammed in the vertical area 26a, the curved area 26b, and the horizontal area 26c in the return path 26, the open / close cover 104 is opened and the sheet cassette 200 is moved to the cassette housing space S of the printer main body 102. 1 to the right in FIG. 1 (see FIG. 3). By such an operation, the entire area of the return path 26 is opened, so that the sheet P can be removed very easily and quickly without breaking the sheet P. The driven roller 54b in each of the transport roller pairs 54 is separated from each of the drive rollers 54a and moves together with the sheet cassette 200, and the sheet roller 224b is separated from the sheet roller 224a and moves together with the sheet cassette 200. It goes without saying that they move. Further, even when the paper P is jammed across the horizontal area 26c of the return path 26 and the vertical area 28a of the reverse re-conveyance path 28, the paper supply cassette 200 is removed from the cassette accommodation space S of the printer main body 102. By pulling out to the right in FIG. 1, the horizontal area 26c of the return path 26 is opened, and the upstream end of the upstream curved area 28b and the downstream end of the vertical area 28a of the reversing re-conveying path 28 are opened. In addition, the paper P can be quickly removed. In this case, the sheet cassette 200 is pulled out in the transport direction of the sheet P along the horizontal area 26c of the return path 26, and the upper surface of the horizontal area 26c of the return path 26 and the reverse re-transport path 28 Due to being provided integrally with the paper feed cassette 200, there is no possibility that the paper P will be broken when the paper feed cassette 200 is pulled out. The fact that the upper surface of the horizontal area 26c of the return path 26 and the reverse re-transport path 28 are integrally provided in the paper feed cassette 200 also contributes to downsizing of the entire printer main body 102, simplification of the configuration, and cost reduction. Things. When the paper feed cassette 200 is pulled out, the paper feed path 22 is also opened.
[0034]
When pulling out the sheet cassette 200 from the cassette accommodating space S of the printer main body 102 to the right in FIG. Accordingly, each of the guided plate portions 228 provided in the paper feed cassette 200 moves along the guide grooves 50c formed in the printer main body 102 in the extending direction of the horizontal area 26c of the return path 26. Because it is slid, it can be pulled out easily and smoothly. When the sheet cassette 200 is pulled out, the lower conveyance guide plate 235 existing at the lower end of each of the width direction position regulating members 230 contacts the upper end of the rib 50b formed on the bottom wall 50 of the printer main body 102. Although it is lifted upward, since a predetermined gap is formed between the lower edge of the through hole 232 of the width direction position regulating member 230 and the lower surface of the area 202B of the bottom wall 202 of the paper feed cassette 200, the width is increased. Each of the direction position regulating members 230 is smoothly lifted upward, and does not hinder the operation of pulling out the sheet cassette 200. In addition, each upstream end of the rib 202a formed on the bottom wall 202 of the sheet cassette 200, which is located on the downstream side of each of the width direction position regulating members 230, is inclined downward toward the downstream, The upstream end of each of the ribs 50b formed on the bottom wall 50 of the printer main body 102 is inclined upward toward the downstream. These inclinations contribute to the smooth conveyance of the paper P. The inclination of each of the ribs 50b allows the upward movement of each of the width direction position regulating members 230 to be smoothly performed when the sheet cassette 200 is pulled out.
[0035]
When the paper cassette 200 is accommodated in the cassette accommodating space S of the printer main body 102 after the above-described jam processing is completed, each of the guided plate portions 228 provided in the paper cassette 200 is replaced with the printer main body 102. By fitting the sheet cassette 200 leftward in FIG. 2 by fitting it into the guide groove 50c formed in FIG. As described above, when the sheet cassette 200 is mounted in the cassette accommodation space S of the printer main body 102, the lower surface of the bottom wall 202 of the sheet cassette 200 (more specifically, the lower end of each of the ribs 202a) and the cassette accommodation space S A horizontal area 26c which is a partial area of the return path 26 is formed between the bottom wall 50 of the space S, and thus the upper surface of the bottom wall 50 of the printer main body 102 (more specifically, the upper end of each of the ribs 50b). In addition, the entire area of the return path 26, the reverse re-transport path 28, and the upstream of the image forming transport path 20 are mutually connected. Further, a paper feed path 22 is formed between the printer body 102 and the paper feed roller 224b is pressed against the paper feed roller 224a to form a paper feed roller pair 224. Furthermore, each of the driven rollers 54b is pressed against each of the drive rollers 54b, and a pair of transport rollers 54 is formed.
[0036]
In the above embodiment of the laser printer 100 according to the present invention, the frame 220 of the paper feed cassette 200 is provided with the vertical area 28a and the upstream curved area 28b of the reverse re-conveying path 28. Another embodiment in which substantially the entire area of the reversing re-conveying path 28 is disposed on the frame 220 is also possible. As described above, it is preferable that at least a partial area of the reverse re-conveying path 28 is provided in the end portion of the sheet feeding cassette 200 in the sheet feeding direction.
[0037]
【The invention's effect】
According to the image forming apparatus of the present invention, the sheet is broken both when the paper jam occurs in the return path or when the paper jam occurs across the return path and the reverse re-conveyance path. Allows easy and quick removal of paper without the need. In addition, when a sheet fed from a sheet cassette and having an image on one side is conveyed along a return path to apply an image on the other side, the position of the sheet in the width direction is easily and reliably prevented. To be able to Furthermore, it is possible to make the whole compact, simple in construction and cost-effective.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an overall configuration of an embodiment of a laser printer configured according to the present invention.
FIG. 2 is a schematic cross-sectional view taken along the line AA of FIG. 1, and is a schematic cross-sectional view showing substantially only one side in the width direction of the printer main body.
FIG. 3 is a schematic sectional view showing a state in which a paper feed cassette is pulled out from a main body of the laser printer shown in FIG. 1;
[Explanation of symbols]
20 Image forming transport path
22 Paper feed path
24 Reverse transport path
24a curved area
24b Vertical evacuation area
26 Return route
26a Vertical area
26b Curved area
26c horizontal area
28 Reverse re-transport path
28a Vertical area
28b Upstream curve area
28c Downstream curved area
30 discharge path
50 Bottom wall of printer body
100 laser printer
102 Printer
200 paper cassette
230 width direction position regulating means
231 Position control plate in width direction
P paper
S Cassette storage space

Claims (5)

A sheet cassette, which is detachably mounted in a cassette accommodation space provided in the apparatus main body and has a bottom wall, an image forming conveyance path on which an image is formed on one side of a sheet to be conveyed, and a sheet cassette accommodated in the sheet cassette. Paper feed path for supplying the fed paper upstream of the image forming transport path, a reverse transport path in which the transport direction of the paper selectively introduced from the downstream of the image forming transport path is reversed, and a reverse transport path. A return path in which the reversely conveyed sheet is returned in the same front and back direction, and a reverse re-conveyance path in which the sheet returned through the return path is reversed and re-conveyed upstream of the image forming conveyance path. In the provided image forming apparatus,
A bottom wall is provided in the storage space, the reverse re-transport path is provided in an end of the sheet cassette in the sheet feeding direction, and the bottom wall of the sheet cassette is mounted when the sheet cassette is mounted. A part of the return path is formed between the lower surface of the feeder and the upper surface of the bottom wall of the storage space, and the sheet cassette can be pulled out in the downstream direction along the part of the return path. When the paper cassette is pulled out, the partial area of the return path is opened,
An image forming apparatus comprising: The apparatus main body has a bottom wall, the bottom wall of the accommodation space is constituted by the bottom wall of the apparatus main body, and the image forming / conveying path extends substantially horizontally in a vertical central portion of the apparatus main body. The space is disposed below the image forming conveyance path, and when the sheet cassette is mounted in the storage space, a return path is provided between the lower surface of the bottom wall of the sheet cassette and the upper surface of the bottom wall of the apparatus main body. The image forming apparatus according to claim 1, wherein the partial area is formed. The reverse transport path includes a curved area that curves upward from the downstream of the image forming transport path, and a vertical retreat area that extends substantially vertically upward from the downstream end of the curved area, and the return path includes the reverse transport path of the reverse transport path. A vertical region that is branched from the downstream end of the curved region and extends substantially vertically downward, a curved region that curves from the downstream end of the vertical region in the upstream direction of the image forming conveyance path, and substantially horizontally and from the downstream end of the curved region. A horizontal region extending in the upstream direction of the image forming conveyance path, wherein a lower surface of the bottom wall of the sheet cassette and an upper surface of the bottom wall of the apparatus main body are formed by mounting the sheet cassette in the accommodation space. The image forming apparatus according to claim 2, wherein the partial area of the return path formed therebetween includes at least the horizontal area of the return path. The vertical retreat area of the reverse transport path, the vertical area of the return path, and the upstream area of the curved area extend in the vertical direction along the end of the apparatus main body in the downstream direction of the image forming transport path to form an image. In the downstream direction of the transport path, an opening / closing cover is provided at an edge of the apparatus main body, and when the open / close cover is opened, the vertical retreat area of the reverse transport path, the vertical area of the return path, and the upstream area of the curved area are returned. The image forming apparatus according to claim 3, wherein the image forming apparatus is opened. On the bottom wall of the paper feed cassette, the width direction position of the paper accommodated in the paper feed cassette and the width direction position of the paper conveyed in the partial area of the return path are the same width direction position and the same width. The image forming apparatus according to any one of claims 1 to 4, further comprising a sheet width direction position regulating unit that can regulate the sheet width at the same time.

Images