JP2004059278A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a positional deviation in a horizontal direction of sheet feeding devices additionally provided in a state superimposed on a device body. <P>SOLUTION: A plurality of sheet feeding devices 40, 50 detachably equipped with sheet storing means 41, 51 are additionally provided on a lower part of the device body. Horizontally positioning of the sheet feeding devices additionally provided in a vertical direction is carried out by a plurality of positioning means 30, 31 provided between the upper and lower sheet feeding devices 40, 50. Therefore, expanding or narrowing of a lower side of a supporting member 47 holding a sheet storing means 41 caused by bending of an upper plate 48 of the upper sheet feeding device 40 is prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of additionally providing a sheet feeding device having a sheet storage unit.
[0002]
[Prior art]
In conventional image forming devices such as laser printers, copiers, and facsimile machines, the number of sheets that can be fed is increased by enabling the addition of an optional feeder, which is a sheet feeding device with a sheet storage section at the bottom of the device. There are some that allow you to use differently sized sheets.
[0003]
Here, when such an optional feeder is added, if the positioning of the optional feeder in the left-right (horizontal) direction is not performed properly, the positioning of the sheet cassette as the sheet storage means is not performed properly. In this case, printing (image formation) accuracy is directly affected. For this reason, when a plurality of option feeders are provided one above the other, a positioning means is provided between the option feeders, and the positioning means is used to position the option feeder in the left-right direction.
[0004]
Note that this optional feeder has a frame having left and right supporting members for holding both side ends of the sheet feeding cassette and an upper plate for connecting the left and right supporting members, and the positioning means is a supporting member or It is composed of a locking projection formed on the upper plate, and a locking recess formed on the other of the support member or the upper plate and locking the locking projection.
[0005]
[Problems to be solved by the invention]
By the way, in an image forming apparatus in which such an optional feeder can be added, the upper plate of the optional feeder may be bent depending on the load of the apparatus main body or the installation state. When the upper plate bends in this way, the distance between the lower ends of the left and right support members becomes wider or narrower. Therefore, when the positioning means for positioning the optional feeder is provided at one place, the upper optional feeder and the lower In some cases, the position of the optional feeder in the left-right direction is shifted.
[0006]
FIG. 4 shows the image forming apparatus (laser beam printer) viewed from the front side, in which two optional feeders 140 and 150 are added to the image forming apparatus. The optional feeders 140 and 150 are provided with a paper feed cassette 146 and a paper feed cassette 156 for storing sheets detachably from the front side (perpendicular to the paper surface). Sheets are fed out of the paper feed cassette 146 and the paper feed cassette 156 to the near side in the vertical direction of the paper, conveyed upward, inverted, and sent to the image forming unit 201 to form an image. FIG. 4 shows a state in which the lower side between the left and right support members 142 of the first option feeder 140 is widened by bending the upper plate 141 of the upper first option feeder 140 downward.
[0007]
In this case, a projection 143 projecting from the bottom surface of the support member 142 of the first option feeder 140 for positioning the first option feeder 140 and the second option feeder 150 thereunder in the left-right direction, and a second option Since the positioning means 130 constituted by the locking recess 152 formed at one end of the upper plate 151 of the feeder 150 is located at one position, the lower spread between the support members of the first option feeder 140 cannot be corrected, The second option feeder 150 is located on the left side of the predetermined position.
[0008]
Therefore, the sheet fed from the paper feed cassette 156 of the second option feeder 150 is conveyed to the image forming apparatus main body 200 in a state shifted to the left. In this case, the reference point A in the width direction of the accommodated sheet is located on the left side of the reference point B in the width direction of the sheet when forming an image in the image forming unit 201 in the image forming apparatus main body. The shifted image is shifted to the right in the width direction of the sheet. Note that the position of the sheet feeding cassette 146 of the first option feeder 140 may be shifted, and in this case, the image formed on the sheet sent from the sheet feeding cassette 146 is shifted in the sheet width direction.
[0009]
FIG. 5 is a view as seen from the same direction as FIG. 4. The lower side between the support members of the first option feeder 140 is narrowed by the upper plate 141 of the first option feeder 140 bending upward. Is shown.
[0010]
In this case, since the positioning means 130 of the first and second optional feeders 140 and 150 is located at one location, the narrowing between the support members of the first optional feeder 140 cannot be corrected, and the second optional feeder 150 cannot be corrected. It will be located on the right side of the predetermined position.
[0011]
Therefore, the sheet fed from the paper feed cassette 156 of the second option feeder 150 is conveyed to the image forming apparatus main body 200 in a state where the sheet is shifted rightward. In this case, since the reference point A of the sheet is located on the right side of the reference point B of the image forming unit 201 in the image forming apparatus main body, the image formed on the sheet is shifted to the left.
[0012]
Therefore, the present invention has been made in view of such a current situation, and it is possible to prevent an optional feeder (sheet feeding device) added in a state of being superposed on the apparatus main body from being displaced in the left-right (horizontal) direction. It is an object of the present invention to provide an image forming apparatus capable of performing the above.
[0013]
[Means for Solving the Problems]
The present invention is an image forming apparatus capable of vertically adding a plurality of sheet feeding devices in which a sheet storage unit is detachably attached to a lower portion of the apparatus main body, wherein the sheet feeding device is provided with a vertically extending sheet feeding device. The positioning in the horizontal direction is performed by a plurality of positioning means provided between the upper and lower sheet feeding devices.
[0014]
Further, according to the present invention, the expandable sheet feeding device includes a support member arranged to face each side of the sheet storage means and a top plate connecting the support members, and The positioning means includes a locking protrusion formed on one of the support member or the upper plate, and a locking recess formed on the other of the support member or the upper plate and locking the locking protrusion. It is characterized by having.
[0015]
Further, the present invention is characterized in that the support members are arranged opposite to each other in a sheet feeding direction, and support both side ends of the sheet storage means mounted in the sheet feeding direction.
[0016]
Further, according to the present invention, there is provided an image in which a plurality of sheet feeding devices in which sheet storage means are detachably mounted are vertically arranged at a lower portion of the apparatus main body, and positioning means for positioning the vertically arranged sheet feeding devices is provided. In the forming apparatus, the positioning means regulates deformation of the sheet feeding apparatus in a horizontal direction orthogonal to a sheet feeding direction from the sheet storage means.
[0017]
Further, in the invention, it is preferable that the attaching / detaching direction of the sheet storage means and the sheet feeding direction from the sheet storage means are the same direction.
[0018]
Further, according to the present invention, the sheet feeding device includes a support member that is disposed to oppose each side to hold both side ends of the sheet storage unit, and an upper plate that couples the support member. The positioning means fits a locking projection formed on one of the support member or the upper plate and a locking recess formed on the other of the support member or the upper plate. By combining them, the deformation of the sheet feeding device is regulated.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0020]
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.
[0021]
In FIG. 1, reference numeral 100 denotes a laser beam printer, and 100A denotes a laser beam printer main body (hereinafter, referred to as a printer main body). The printer main body 100A, which is an apparatus main body, has an image provided with a photosensitive drum 1, a transfer unit 5, and the like. A forming unit 101, a fixing unit 20 for fixing an image formed by the image forming unit 101 on a sheet, and the like are provided.
[0022]
Here, the photoconductor drum 1 is driven to rotate counterclockwise by a driving unit (not shown), and the surface of the photoconductor drum 1 is uniformly charged around the photoconductor drum 1 in order according to the rotation direction. A charging roller 2, a scanner unit 3 for irradiating a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 1, and a toner image by attaching toner to the electrostatic latent image on the photosensitive drum 1 A developing unit 4 for developing the toner image, a transfer unit 5 for transferring the toner image on the photosensitive drum 1 to the sheet S, and a cleaning device 6 for removing the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer. ing.
[0023]
In the present embodiment, the photoconductor drum 1 is configured by applying an organic photoconductor layer (OPC photoconductor) to an outer peripheral surface of, for example, an aluminum cylinder having a diameter of 30 mm, and both ends of the photoconductor drum 100A. Is rotatably supported by a support member (not shown) provided at the other end, and is driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end. I have.
[0024]
The charging roller 2 constitutes a charging unit of a contact charging system. The charging roller 2 is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the charging roller 2 to charge the photosensitive member. The surface of the drum 1 is uniformly charged.
[0025]
The scanner unit 3 includes a polygon mirror 8 rotated at a high speed by a scanner motor (not shown) and an imaging lens 9, and rotates image light corresponding to an image signal emitted by a laser diode (not shown) at a high speed. After being reflected by the polygon mirror 8, the surface of the charged photosensitive drum 1 is selectively exposed through an imaging lens 9, thereby forming an electrostatic latent image on the photosensitive drum. ing.
[0026]
The developing device 4 includes a developing container 4 a containing toner, a developing roller 10, and a supply roller 11 for supplying toner to the developing roller 10. The photosensitive drum 1, the charging roller 2, the developing device 4, and the cleaning device 6 are integrally formed as a process cartridge 7. The process cartridge 7 is attached to and detached from the printer main body 100A in the sheet feeding direction. It is freely attached.
[0027]
The transfer unit 5 includes a transfer roller 12 disposed at a position facing the photoconductor drum 1, applies a positive charge from the transfer roller 12 to the sheet S, and generates an electric field generated by the charge. The negative toner image on the photosensitive drum 1 is transferred to the sheet S in contact with the drum 1.
[0028]
The fixing unit 20 includes a heating roller 21a and a pressure roller 21b that is in pressure contact with the heating roller 21a, and applies heat and pressure to the sheet S on which the toner image has been transferred by the heating roller 21a and the pressure roller 21b. Thereby, the toner image transferred to the sheet S is fixed.
[0029]
Reference numerals 40 and 50 denote two upper and lower optional feeders, which are sheet feeding devices added to the bottom of the printer main body 100A. The upper and lower two optional feeders (hereinafter, referred to as an upper optional feeder and a lower optional feeder) 40 and 50 are respectively provided with sheet cassettes 41 and 51 serving as sheet storage means and sheets stored in the sheet cassettes 41 and 51. And sheet feeding units 42 and 52 for feeding S to the image forming unit 101.
[0030]
Here, the sheet feeding units 42 and 52 face sheet feeding rollers 43 and 53 (half-moon rollers) as sheet feeding means disposed above the sheet feeding cassettes 41 and 51, and face the sheet feeding rollers 43 and 53. And separation pads 44 and 54 attached in a state of having a biasing force in the direction of the paper feed roller.
[0031]
When an image is formed on a sheet S in the laser beam printer 100 having such a configuration, first, the process cartridge 7 is driven in synchronization with printing (image formation) timing, and the photosensitive drum 1 is driven in accordance with the drive. Are driven to rotate counterclockwise, and the scanner unit 3 is sequentially driven. By this driving, the charging roller 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1, and the scanner unit 3 performs exposure on the peripheral surface of the photosensitive drum 1 in accordance with an image signal, and An electrostatic latent image is formed on the surface.
[0032]
Next, the developing roller 10 in the developing device 4 transfers the toner to the low-potential portion of the electrostatic latent image formed on the peripheral surface of the photoconductor drum, thereby causing the toner on the peripheral surface of the photoconductor drum 1 to move. An image is formed (developed).
[0033]
In parallel with the toner image forming operation, for example, the sheets S stored in the sheet cassette 41 of the upper optional feeder 40 are separated one by one by the sheet feeding roller 43 and the separation pad 44, and the uppermost sheet S Only the registration roller pair 17 is fed. Thereafter, the leading end is abutted against the stopped registration roller pair 17 to form a loop, thereby correcting skew.
[0034]
Next, after correcting the skew of the sheet S in this manner, when the leading end of the toner image on the peripheral surface of the photosensitive drum is rotated and conveyed to the point facing the transfer roller 12, the sheet S is moved to the point facing the transfer roller 12. The registration roller pair 17 starts rotating so that the printing start position of the register S coincides with the image writing position, and feeds the sheet S to the transfer unit 5. The toner image on the photosensitive drum 1 is transferred to the sheet S fed to the transfer unit 5 by the electric field formed between the photosensitive drum 1 and the transfer roller 12 in this manner.
[0035]
Next, the sheet S to which the toner image has been transferred is separated into curvatures by the curvature of the photosensitive drum 1 and is carried into the fixing unit 20, where the toner image is heat-fixed by the fixing unit 20, and then the sheet discharge roller pair 22. As a result, the paper is discharged from the paper discharge unit 23 to the outside of the main body with the image face down.
[0036]
When the sheets S are fed from the lower optional feeder 50 to the image forming unit 101, the sheets S stored in the sheet cassette 51, which can be stacked large, are fed one by one by the sheet feeding roller 53 and the separation pad 54. The sheet is separated, and only the uppermost sheet is fed to the pair of conveying rollers 45 mounted in the upper optional feeder 40. Thereafter, the sheet S is transported by the transport roller 45 to the registration roller pair 17. Subsequent operations are the same as described above.
[0037]
FIG. 2 is a front view of the printer main body 100A (viewed from the right side in FIG. 1). In FIG. 2, reference numerals 46 and 56 denote frames of upper and lower option feeders 40 and 50, respectively. Here, the frames 46, 56 of the upper and lower optional feeders 40, 50 have the left and right support members 47, 57 for detachably holding the sheet cassettes 41, 51, respectively, and the left and right support members 47, 57 on the upper side. And upper plates 48 and 58 for coupling.
[0038]
In this embodiment, the paper feed cassettes 41 and 51 are detachably mounted on the upper and lower optional feeders 40 and 50 along the sheet feeding direction, and the left and right support members 47 and 57 are thus attached to the sheet. The sheet cassettes 41 and 51 mounted along the sheet feeding direction are opposed to each other along the sheet feeding direction so as to hold both side ends. The sheet cassettes 41 and 51 can be detached from the front side of the printer main body 100A.
[0039]
Reference numerals 30 and 31 denote first and second positioning means for positioning the upper and lower optional feeders 40 and 50 in the left-right direction. In the present embodiment, the first and second positioning means 30 and 31 are formed by a projection 49 provided on the bottom surface of the support member 47 of the upper option feeder 40 and an upper plate 58 of the lower option feeder 50. It is constituted by locking recesses 59 formed at both ends.
[0040]
In the present embodiment, the upper and lower option feeders 40 and 50 are positioned in the left-right direction (horizontal direction) by the two left and right positioning units 30 and 31.
[0041]
Here, the upper and lower option feeders 40 and 50 are positioned by the two left and right positioning means 30 and 31 as described above, so that the upper plate 48 of the upper option feeder 40 is bent and thus the upper option feeder 40 is bent. Of the lower side between the left and right support members can be prevented.
[0042]
Then, by preventing the lower side spread and narrowing between the support members of the upper option feeder 40 in this manner, the upper and lower option feeders 40 and 50 are prevented from being displaced in the left-right direction (see FIGS. 4 and 5). be able to. The upper option feeder 40 does not bend because the bottom surface 100B of the printer main body 100A is strong, so that the upper option feeder 40 does not shift in the left-right direction.
[0043]
As a result, not only the sheets fed from the sheet cassette 41 of the upper option feeder 40 but also the sheets fed from the sheet cassette 51 of the lower option feeder 50 are not displaced in the left-right direction without the printer main body 100A being displaced. As a result, as shown in FIG. 2, the reference point A in the width direction of the stored sheet and the width of the sheet when the image is formed in the image forming unit 101 in the printer main body. The reference point B matches, and the accuracy of the printing position in the sheet width direction is improved. Since the position of the sheet sent out from the sheet cassette 41 provided in the upper optional feeder 40 does not shift, the accuracy of the printing position in the sheet width direction is improved.
[0044]
As described above, even when the upper and lower option feeders 40 and 50 are added, the horizontal positioning of the upper and lower option feeders 40 and 50 is performed by two positioning means provided between the upper and lower option feeders 40 and 50. By performing the steps 30 and 31, it is possible to prevent the displacement of the additional upper and lower optional feeders 40 and 50 in the horizontal direction with a simple configuration.
[0045]
In the above description, the case where two positioning means are provided symmetrically has been described. However, the present invention is not limited to this, and three or more positioning means may be provided if necessary.
[0046]
By the way, the case where two optional feeders are added below the printer main body 100A has been described, but the present invention is not limited to this, and three or more optional feeders may be added.
[0047]
Next, a second embodiment of the present invention in which three or more optional feeders are added below the printer main body 100A will be described.
[0048]
FIG. 3 is a side view of a laser beam printer according to the present embodiment, which is an example of an image forming apparatus in which three optional feeders are added below the printer main body. 2, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts.
[0049]
In the drawing, reference numeral 60 denotes a third option feeder which is added below the lower option feeder 50. The third option feeder 60 is, like the upper and lower option feeders 40 and 50, a sheet feed cassette 61 and a sheet feeder. A sheet feeding unit (not shown) that feeds the sheets stored in the cassette 61 to the image forming unit 101 is provided. Further, it has a frame including left and right support members 62 for detachably holding the sheet cassette 61 and an upper plate 68 for connecting the left and right support members 62 on the upper side.
[0050]
When a sheet is fed from the third option feeder 60 to the image forming unit 101, the sheets stored in the sheet feeding cassette 61 are separated one by one by a sheet feeding roller and a separation pad, and only the top sheet is separated. The sheet is conveyed to the pair of registration rollers 17 by the pair of conveyance rollers 55 mounted in the lower option feeder 50 and the pair of conveyance rollers 45 mounted in the upper option feeder 40 shown in FIG. Transport to Subsequent operations are the same as described above.
[0051]
In FIG. 3, reference numerals 32 and 33 denote third and fourth positioning means for positioning the lower and third optional feeders 50 and 60 in the left-right direction. In the present embodiment, these two third and fourth positioning means 32 and 33 are provided with a convex portion 59 a protruding from the bottom surface of the support member 57 of the lower option feeder 50 and a third upper and lower positioner. It is constituted by locking recesses 69 formed at both ends of the plate 68.
[0052]
In the present embodiment, the positioning of the lower and third option feeders 50, 60 in the left-right direction is performed by these two positioning means 32, 33.
[0053]
Here, according to the configuration of the present embodiment, the upper plate 48 of the upper option feeder 40 is flexed by positioning the upper and lower option feeders 40 and 50 by the two left and right positioning means 30 and 31. Therefore, it is possible to prevent the lower side spread and narrowing between the left and right support members of the upper option feeder 40 due to this.
[0054]
Also, by positioning the lower and third option feeders 50 and 60 by the two left and right positioning means 32 and 33, the upper and lower plates 58 of the lower option feeder 50 are bent by bending the upper plate 58 of the lower option feeder 50. Spreading and narrowing of the lower side between the supporting members can be prevented.
[0055]
As a result, the sheets fed from the paper feed cassettes 51 and 61 of the lower and third optional feeders 50 and 60 are conveyed to the printer main body 100A without shifting the position in the left-right direction. As shown in FIG. 3, the reference point A of the sheet coincides with the reference point B of the image forming unit 101 in the printer main body, and the accuracy of the printing position in the sheet width direction is improved.
[0056]
【The invention's effect】
As described above, according to the present invention, the horizontal positioning of a plurality of sheet feeding devices extended vertically in the lower portion of the apparatus main body is performed by a plurality of positioning means provided between the upper and lower sheet feeding devices. By doing so, it is possible to prevent the sheet feeder added in a state of being stacked on the apparatus main body from being displaced in the horizontal direction. Thereby, the accuracy of the printing position of the sheet can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a laser beam printer as an example of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a view for explaining a configuration of a positioning means for positioning two optional feeders added to the laser beam printer.
FIG. 3 is a diagram illustrating a configuration of a positioning unit that positions three optional feeders added to a laser beam printer as an example of an image forming apparatus according to a second embodiment of the present invention.
FIG. 4 is a diagram illustrating a problem of positioning means when two optional feeders are added to a conventional image forming apparatus.
FIG. 5 is a diagram illustrating another problem of the positioning unit when two optional feeders are added to the conventional image forming apparatus.
[Explanation of symbols]
30 First positioning means 31 Second positioning means 32 Third positioning means 33 Fourth positioning means 40 Upper option feeder 41 Paper feed cassette 42 Sheet feeder 46 Frame 47 Support member 48 Upper plate 49 Convex part 50 Lower part Optional feeder 51 Paper feed cassette 52 Sheet feeder 56 Frame 57 Support member 58 Upper plate 59 Locking recess 59a Convex portion 60 Third option feeder 61 Paper cassette 62 Support member 68 Upper plate 69 Locking recess 100 Laser beam printer 100A Printer body 101 Image forming unit S sheet

Claims (6)

An image forming apparatus capable of vertically adding a plurality of sheet feeding apparatuses to which a sheet storage unit is detachably attached in a lower part of the apparatus main body,
The image forming apparatus according to claim 1, wherein a plurality of sheet feeding devices provided in the vertical direction are positioned in a horizontal direction by a plurality of positioning means provided between the upper and lower sheet feeding devices. The extendable sheet feeding device includes a support member that is arranged to face each side of the sheet storage unit and an upper plate that couples the support member. A locking projection formed on one of the support member or the upper plate, and a locking recess formed on the other of the support member or the upper plate and locking the locking projection. The image forming apparatus according to claim 1. The image forming apparatus according to claim 2, wherein the support members are arranged to face each other in a sheet feeding direction, and support both side ends of the sheet storage unit mounted in the sheet feeding direction. An image forming apparatus, comprising: a plurality of sheet feeding devices in which sheet storage means are detachably mounted; and a positioning unit for positioning the vertically arranged sheet feeding devices is provided at a lower portion of the apparatus main body. ,
The image forming apparatus according to claim 1, wherein the positioning unit regulates deformation of the sheet feeding device in a horizontal direction orthogonal to a sheet feeding direction from the sheet storage unit. 5. The image forming apparatus according to claim 4, wherein the direction in which the sheet storage unit is attached and detached is the same as the direction in which sheets are fed from the sheet storage unit. The sheet feeding device has a structure in which a support member disposed to oppose each side to hold both side ends of the sheet storage unit and an upper plate that couples the support member, and a lower portion of the sheet storage unit is opened. The positioning means may be configured such that the locking protrusion formed on one of the support member or the upper plate and the locking recess formed on the other of the support member or the upper plate are fitted to each other. The image forming apparatus according to claim 4, wherein the deformation of the sheet feeding device is restricted.

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