JP2004224507A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus provided with a low-priced sheet loading unit. <P>SOLUTION: An end of the sheet loading unit 50 set on the downstream side in the sheet carrying direction is formed of a first sheet loading member 9, and an end of the sheet loading unit 50 set on the upstream side in the carrying direction is formed of a second sheet loading member 4. A holder member 8 for slidably (movably) holding side regulating means 5R and 5L is arranged between the first and the second sheet loading members 4 and 9. A projection part 11A formed in a member 11 forming an image forming apparatus main body 104 is arranged between the holder member 8 and the first sheet loading member 9 so that the projection part 11A forms a part of the sheet loading unit 50. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to a configuration of a sheet stacking unit that stacks sheets.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, image forming apparatuses such as printers, facsimile machines, copiers, and composite devices thereof have a sheet stacking section for stacking sheets, and supply sheets stacked on the sheet stacking section during image formation. There is a type in which the paper is fed to an image forming unit by a paper device.
[0003]
Here, such a sheet stacking unit is provided so as to be slidable (movable) at both ends in the width direction orthogonal to the sheet conveying direction of the sheet stacking unit, and is provided at both ends of the sheets stacked on the sheet stacking unit. Some include side regulating means for regulating the position.
[0004]
FIG. 6 shows a schematic configuration of a laser beam printer which is an example of such a conventional image forming apparatus. The laser beam printer 100 includes an image forming unit 101, and a recording paper or the like provided on the image forming unit 101. And a transfer unit 103 for transferring a toner image to the sheet P, a fixing unit 16 for fixing the toner image transferred by the transfer unit 103 to the sheet P, and the like. .
[0005]
Here, the sheet feeding unit 102 forms a sheet feeding tray 4 that forms an upstream end of the sheet stacking unit 110 on which sheets P are stacked in the sheet conveyance direction, and forms a downstream end of the sheet stacking unit 110 in the sheet conveyance direction. The lift plate 9 includes a lift plate 9 on which the front end of the sheet P is placed, a feed roller 12 disposed above the lift plate 9, and a separation pad 13 that is a separation member that presses against the feed roller 12.
[0006]
The lift plate 9 is pushed upward about the shaft 9a by the action of a cam (not shown) and a lift spring 10 during image formation. When the lift plate 9 is pushed up, the sheet P Is pressed against the paper feed roller 12 at a predetermined paper feed pressure.
[0007]
When the sheet P comes into pressure contact with the sheet feeding roller 12 at a predetermined sheet feeding pressure, the sheet feeding roller 12 rotates, and the uppermost sheet P is sent out by the sheet feeding roller 12. The uppermost sheet P is separated and conveyed one by one from the other sheets P by the separation pad 13 and the sheet feeding roller 12, and is conveyed to the transfer unit 103 by the conveying roller 14 and the conveying roller 15. The friction coefficient, contact angle, shape, and the like of the surface of the separation pad 13 are set so that when the separation pad 13 is pressed against the paper feed roller 12, only one top sheet P is conveyed for each paper feed. I have.
[0008]
The image forming unit 101 includes a process cartridge 1 including a photosensitive drum 1a, a developing sleeve 1c, a charging roller 1b, a toner container 1d, and the like, and an electrostatic latent image on the photosensitive drum 1a by exposing the surface of the photosensitive drum 1a. And a laser scanner 2 for forming an image. The laser scanner 2 includes a laser light emitting unit (not shown), a rotating polygon mirror 2a, a return mirror 2b, and the like.
[0009]
Further, the transfer unit 103 forms a transfer nip by pressing the photosensitive drum 1a and the photosensitive drum 1a, and transfers the toner image on the photosensitive drum 1a to the sheet P when the sheet P passes through the transfer nip. And a transfer roller 3 serving as a transfer unit for transferring the image to the printer. The fixing unit 16 includes a heating roller 16a and a pressure roller 16b that is in pressure contact with the heating roller 16a.
[0010]
In FIG. 1, reference numeral 17 denotes a discharge roller, and reference numeral 18 denotes a discharge roller that contacts the discharge roller 17. The sheet P on which the toner image is fixed by the fixing unit 16 is formed by a pair of discharge rollers 17 and 18. The paper is discharged onto a paper discharge tray 19 integrally formed with the paper tray 20.
[0011]
Next, an image forming operation in the laser beam printer 100 thus configured will be described.
[0012]
When the image forming operation is started, first, the photosensitive drum 1a rotates in the direction of the arrow, and is uniformly charged to a predetermined polarity and a predetermined potential by a charging roller 1b supplied from a high-voltage power supply (not shown). Then, laser light emitted based on image information from a laser emitting unit (not shown) of the laser scanner 2 passes through the polygon mirror 2a and the folding mirror 2b to the photosensitive drum 1a whose surface is charged in this way. Irradiation, thereby forming an electrostatic latent image on the photosensitive drum 1a.
[0013]
Next, the toner in the toner container 1d, which has been appropriately charged with the rotation of the developing sleeve 1c, is supplied onto the photosensitive drum 1a and adheres to the electrostatic latent image. And visualized as a toner image.
[0014]
On the other hand, the sheet P stacked and stored in the sheet stacking unit 110 in parallel with the toner image forming operation is sent out by the sheet feeding roller 12, and then separated and conveyed by the separation pad 13 and the sheet feeding roller 12, and Thereafter, the sheet is further conveyed to the transfer unit 103 by the conveying roller pairs 14 and 15.
[0015]
At this time, the leading end of the sheet P is detected by a registration sensor (not shown) provided upstream of the transfer unit 103. Based on a detection signal from the registration sensor, control means (not shown) determines the position of the leading end of the sheet P and the laser scanner. The light emission timing of No. 2 is synchronized. Thus, the toner image formed on the photosensitive drum can be transferred to a predetermined position on the sheet P.
[0016]
Next, the sheet P on which the toner image has been transferred as described above is conveyed to a fixing nip constituted by a heating roller 16a and a pressure roller 16b provided in the fixing unit 16, where the unfixed toner image is heated. -It is pressurized and fixed on the sheet surface.
[0017]
The sheet P on which the toner image has been fixed in this way is discharged onto a discharge tray 19 by a pair of discharge rollers 17 and 18. The untransferred toner remaining on the photosensitive drum 1a without being transferred is stored in a waste toner container 1f by a cleaning blade 1e. Then, the photosensitive drum 1a whose surface has been cleaned repeatedly enters the next image forming process.
[0018]
In the drawing, reference numeral 105 denotes a sheet guide which regulates the position of both side ends in the width direction which is a direction orthogonal to the sheet P sending direction (conveying direction) and guides the sheet P to be sent out. 7, and are slidable in the width direction of the sheet P.
[0019]
As shown in FIG. 8, each of the opposed sheet guides 105 is provided with a rack 106 having a rack 106 a that meshes with a pinion 107. Slide (move) in conjunction with each other.
[0020]
In FIG. 6, reference numeral 108 denotes a guide rail for holding the sheet guide 105 so as to be movable in the width direction, and the guide rail 108 is a molded product. Reference numeral 11 denotes a bottom plate that forms the bottom of the laser beam printer main body 104.
[0021]
Here, in the conventional laser beam printer 100 having such a configuration, the sheet stacking unit 110 for stacking the sheets P includes the sheet feed tray 4, the guide rail 108 having the sheet guide 105, and the lift plate 9. .
[0022]
[Problems to be solved by the invention]
Incidentally, in such a conventional laser beam printer (image forming apparatus), a rack 106 and a pinion 107 are arranged inside a guide rail 108 as shown in FIG. That is, the role of the guide rail 108 is to hold the sheet guide 105 so as to be slidable, stack the sheets P on the surface, and further house the rack 106 and the pinion 107 inside.
[0023]
Here, in general, there is an advantage that the smaller the mechanical component, the lower the cost from the viewpoint of material cost, and the smaller the molded product, the lower the rank of the molding machine can be used, and the lower the cost of the mold.
[0024]
However, the conventional guide rail 108 has a storage section 108a for storing the rack 106 and the pinion 107, as shown in FIG. 8, and a loading section 108b for loading only the sheets shown in FIG. In addition, the guide rail 108 is increased in size due to the provision of the loading portion 108b, and the cost of the guide rail 108 is accordingly increased. As a result, the cost of the sheet stacking unit 110 also increases.
[0025]
Therefore, the present invention has been made in view of such a situation, and has as its object to provide an image forming apparatus having an inexpensive sheet stacking unit.
[0026]
[Means for Solving the Problems]
The present invention is provided such that the sheet stacking section and the sheet stacking section are movably provided at both side ends in the width direction orthogonal to the sheet conveying direction, and regulate the positions of both side ends of the sheets stacked on the sheet stacking section. A first sheet stacking member that forms a downstream end of the sheet stacking section in the sheet conveying direction; and a second sheet forming section that forms an upstream end of the sheet stacking section in the sheet conveying direction. A two-sheet stacking member, and a holding member disposed between the first sheet stacking member and the second sheet stacking member and movably holding the side regulating means, wherein the holding member and the first A convex portion formed on a member constituting the image forming apparatus main body is disposed between the sheet stacking member or between the holding member and the second sheet stacking member, and the convex portion forms one of the sheet stacking portions. Compose It is characterized in that it has to be.
[0027]
Further, according to the present invention, there is provided a moving means for moving the side regulating means provided on both side ends of the sheet stacking section in conjunction therewith, and the moving means is arranged inside the holding member. It is.
[0028]
Further, the invention is characterized in that a member constituting the image forming apparatus main body is a bottom plate arranged below the sheet stacking section.
[0029]
Further, the present invention is characterized in that the bottom plate is made of sheet metal, and the projections are formed by bending the bottom plate at at least three places.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0031]
FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an example of an image forming apparatus according to an embodiment of the present invention. 6, the same reference numerals as those in FIG. 6 indicate the same or corresponding parts.
[0032]
In the drawing, reference numeral 50 denotes a sheet stacking portion for stacking sheets, and 5R and 5L, sheet guides which are slidably provided on both side edges of the sheet stacking portion 50 in the width direction orthogonal to the sheet conveying direction. The sheet guides 5 </ b> R and 5 </ b> L are for preventing the sheet P placed on the sheet stacking section 50 from being skewed at the time of conveyance by regulating the position in the width direction.
[0033]
Reference numeral 8 denotes a guide rail that is a holding member that holds the sheet guides 5R and 5L so as to be slidable in the width direction. As shown in FIG. 2, the guide rail 8 is used to slide the sheet guides 5R and 5L in the width direction. It has extended guide grooves 8R and 8L.
[0034]
Further, as shown in FIG. 3, the sheet guides 5R and 5L include rack portions 6R and 6L each having a rack 6a formed at an opposite side end, and each rack 6a of the rack portions 6R and 6L is It meshes with the pinion 7 (the gear teeth are simplified).
[0035]
The rack portion 6L of the sheet guide 5L follows the guide groove 8L of the guide rail 8, and the rack portion 6R of the opposite sheet guide 5R follows the guide groove 8R of the guide rail 8, so that the rack portions 6R, By engaging each of the racks 6a of the 6L with the pinion 7, the sheet guides 5R and 5L can move in conjunction with the width direction of the sheet P and can regulate the width direction of the sheet P.
[0036]
In FIG. 3, reference numerals 6La and 6Lb denote elastic portions provided at the end of the rack portion 6L of the sheet guide 5L on the side opposite to the rack forming side. Is always in pressure contact with
[0037]
The rack 6a of the rack 6L is engaged with the pinion 7, and the elastic bodies 6La and 6Lb provided at the end of the rack 6L opposite to the rack forming side are attached to the inner wall surface 8a of the guide rail 8. By constantly pressing, the sheet guide 5L can be fixed at a predetermined position. Thereby, the sheet guide 5L can obtain a regulating force for regulating the position of the sheet P.
[0038]
A similar elastic portion (not shown) is also provided on the rack portion 6R of the facing sheet guide 5R. The elastic portion is always pressed against the inner wall of the guide rail, and the rack 6a of the rack portion 6R is fixed to the pinion 7. By engaging with each other, the sheet guide 5R can also obtain a regulating force for regulating the position of the sheet P.
[0039]
By the way, in the present embodiment, the sheet stacking unit 50 includes the sheet feeding tray 4, the guide rail 8 including the sheet guides 5R and 5L, the lift plate 9, and a part of the bottom plate 11, as shown in FIG. It is constituted by the formed convex shape 11A.
[0040]
That is, in the present embodiment, the lift plate 9 that is the first sheet stacking member that forms the downstream end of the sheet stacking section 50 in the sheet conveyance direction and the upstream end of the sheet stacking section 50 that forms the sheet conveyance direction are formed. The portion between the paper feed tray 4 as the second sheet stacking member to be formed is formed by the guide rail 8 and the convex shape 11A of the bottom plate 11.
[0041]
With such a configuration, it is not necessary to cover the entire portion between the sheet feed tray 4 and the lift plate 9 with only the guide rail 8, and the guide rail 8 can be reduced in size.
[0042]
By the way, in the present embodiment, the guide rail 8 can hold the sheet guides 5R and 5L so as to be slidable, and a rack unit that is a moving unit that slides (moves) the sheet guides 5R and 5L in conjunction with each other. The minimum size is such that 6R, 6L and the pinion 7 can be stored.
[0043]
When the guide rail 8 has such a size, for example, in FIG. 8 described above, there is no stacking portion 108b for only loading a sheet which is a dead space indicated by X, and the cost of the guide rail 108 can be reduced. It becomes.
[0044]
On the other hand, when the guide rail 8 is set to the minimum necessary size, a gap is formed between the lift plate 9 and the guide rail 8, but in the present embodiment, the gap of the bottom plate 11 is formed in the gap. A convex shape 11A having a flat upper surface is formed at a corresponding position, and the convex shape 11A of the bottom plate 11 is arranged between the lift plate 9 and the guide rail 8, so that the sheet P can be added for bridging. The sheet stacking section 50 without gaps can be formed without providing any components.
[0045]
In this way, the convex shape 11A formed on the sheet metal bottom plate 11, which is the original component of the laser beam printer main body 104, is formed in the gap between the sheet stacking portions 50 generated by minimizing the size of the guide rail 8. By arranging, a part of the sheet stacking unit 50 can be formed by the convex shape 11A having a flat upper surface.
[0046]
By forming a part of the sheet stacking portion 50 with the convex shape 11A, the size of the guide rail 8 can be reduced, and the cost of the guide rail 8 can be reduced. In addition, by reducing the size of the guide rail 8 and configuring a part of the sheet stacking section 50 to be covered by the existing bottom plate 11, the cost of the sheet stacking section 50 can be reduced, and as a result, the inexpensive sheet stacking section 50 can be reduced. Can be provided.
[0047]
By the way, the bottom plate 11 is fastened to both side plates (not shown) of the laser beam printer main body 104 and functions to support the rigidity of the laser beam printer main body 104. In the present embodiment, as shown in FIG. As described above, the convex shape 11A of the bottom plate 11 is formed by bending the entire region of the bottom plate 11 in the width direction at four locations.
[0048]
Since the bottom plate 11 has the bent portions 11a to 11d covering the entire width direction of the four (plural) bottom plates 11, the rigidity of the laser beam printer main body 104 can be increased. Then, by increasing the rigidity of the laser beam printer main body 104 in this manner, stable image formation can be performed.
[0049]
The bottom surface of the bottom plate 11 formed by bending the entire region in the width direction at four places in this manner has a concave shape as shown in FIG. 4 which is a lower perspective view of FIG. Since it cannot be seen from the outside, the shape of the back surface of the bottom plate 11 does not affect the design.
[0050]
Further, in the present embodiment, the sheet guides 5R and 5L extend to a flat upper surface forming a part of the sheet stacking portion 50 having the convex shape 11A of the bottom plate 11, as shown in FIG. When the sheet guides 5R and 5L are extended to the flat upper surface of the convex shape 11A as described above, when the sheet guides 5R and 5L are moved, the sheet guides 5R and 5L slide on the convex shape made of sheet metal. Operation feeling is improved, and usability can be improved.
[0051]
By the way, in the description so far, the case where the convex shape 11A of the bottom plate 11 is provided on the downstream side of the guide rail 8 in the sheet conveying direction has been described. However, the present invention is not limited to this, and as shown in FIG. The convex shape 11 </ b> A of the bottom plate 11 may be provided on the upstream side of the guide rail 8 in the sheet conveyance direction, that is, between the guide rail 8 and the paper feed tray 4.
[0052]
By providing the protruding shape 11A of the bottom plate 11 on the upstream side of the guide rail 8 in the sheet conveying direction in this way, even if the guide rail 8 is reduced in size for cost reduction, an additional part for bridging the sheet P is provided. , And the flat sheet stacking section 50 without any gap can be formed.
[0053]
Here, when the convex shape 11A of the bottom plate 11 is provided at such a position, the convex shape 11A is formed by bending the entire width of the bottom plate 11 at three locations. Since the bottom plate 11 has the bent portions 11a to 11c over the entire width direction of the three (plural) bottom plates 11, the rigidity of the laser beam printer main body 104 can be increased. Image formation becomes possible.
[0054]
In the above description, the case where the convex shape 11A of the bottom plate 11 is provided on the upstream side or the downstream side of the guide rail 8 in the sheet conveying direction has been described, but the present invention is not limited to this, and the present invention is not limited thereto. May be arranged on both the upstream side and the downstream side of the guide rail 8 in the sheet conveying direction.
[0055]
In the above description, the sheet guides 5R and 5L have been described as being configured to be slid and moved to a position where both sides of the sheet are regulated. However, the present invention is not limited to this. It is needless to say that the same effect can be obtained even when using a structure in which both sides of the sheet are moved to positions for regulating.
[0056]
【The invention's effect】
As described above, according to the present invention, the first sheet stacking member and the holding member disposed between the first and second sheet stacking members that constitute the sheet stacking unit and movably holding the side regulating unit are arranged. By providing a convex portion formed on a member constituting the image forming apparatus main body between the second or the second sheet stacking member and forming a part of the sheet stacking portion by the convex portion, the holding member Can be reduced in size, whereby an image forming apparatus having an inexpensive sheet stacking section can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a laser beam printer as an example of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating an internal configuration of the laser beam printer.
FIG. 3 is a perspective view of a guide rail of the laser beam printer as viewed from below.
FIG. 4 is a lower perspective view of FIG. 2;
FIG. 5 is a diagram showing another configuration of the laser beam printer.
FIG. 6 is a diagram showing a schematic configuration of a conventional laser beam printer.
FIG. 7 is a perspective view of a conventional guide rail viewed from above.
FIG. 8 is a perspective view of a conventional guide rail viewed from below.
[Explanation of symbols]
4 Paper Feed Tray 5R, 5L Sheet Guide 6R, 6L Rack 6La, 6Lb Elasticity 7 Pinion 8 Guide Rail 9 Lift Plate 11 Bottom Plate 11A Convex Shape 50 Sheet Loading Unit 100 Laser Beam Printer 101 Image Forming Unit P Sheet

Claims (4)

A sheet stacking unit, side regulating means provided movably at both end portions in the width direction orthogonal to the sheet conveying direction of the sheet stacking unit, and regulating the positions of both end portions of the sheets stacked on the sheet stacking unit; In the image forming apparatus provided with
A first sheet stacking member that forms a downstream end of the sheet stacking section in the sheet conveyance direction;
A second sheet stacking member that forms an upstream end of the sheet stacking section in the sheet conveyance direction;
A holding member disposed between the first sheet stacking member and the second sheet stacking member and movably holding the side regulating unit;
With
A convex portion formed on a member forming an image forming apparatus main body is arranged between the holding member and the first sheet stacking member or between the holding member and the second sheet stacking member; And a part of the sheet stacking section. Moving means for moving side regulating means provided on both side ends of the sheet stacking section in conjunction with each other,
The image forming apparatus according to claim 1, wherein the moving unit is disposed inside the holding member. 3. The image forming apparatus according to claim 1, wherein the member forming the image forming apparatus main body is a bottom plate disposed below the sheet stacking unit. 4. The image forming apparatus according to claim 3, wherein the bottom plate is made of sheet metal, and the projection is formed by bending the bottom plate at at least three places.

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