JP2005308853A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the degree of freedom large in terms of the design of a carrying unit, a transfer unit and a fixing unit in an image forming apparatus. <P>SOLUTION: The image forming apparatus is constituted by attaching the carrying unit for carrying paper fed from the bundle of paper stored in a paper storing part, the transfer unit for performing the transfer processing of a toner image to the paper P carried by the carrying unit in cooperation with a photoreceptor drum on which a toner image is formed, and the fixing unit for performing the fixing processing of the toner image to the paper P to which the transfer processing is performed by the transfer unit in a unit supporting frame 50 provided to be attached to/detached from an apparatus main body. The unit supporting frame 50 is equipped with a pair of side plates 51 in a width direction and a bottom board 52 laid between the side plates 51, and the bottom board 52 adopts a bottom board 53 for the carrying unit, a bottom board 54 for the transfer unit, and a bottom board 55 for the fixing unit corresponding to the respective units and independent of each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile apparatus, and a printer, and more particularly to a support frame that supports units of various devices that are detachably mounted in the apparatus main body.

  Usually, the image forming apparatus includes a sheet storage unit that stores sheets in a box-shaped apparatus body, a sheet transport unit that transports sheets from the sheet storage unit to the image forming unit, and the sheet storage unit. An image forming unit that performs a toner image transfer process on a sheet fed from the image forming apparatus, and a fixing unit that performs a toner image fixing process on a sheet that has undergone a transfer process in the image forming unit. It has a configuration.

  Conventionally, unit devices such as the conveyance roller of the paper conveyance unit and the transfer roller of the image forming unit are directly mounted on the frame of the main body of the apparatus. However, in this case, the paper jam removal operation and various maintenance operations are performed. Since the degree of freedom in securing a work space in the apparatus main body is small, in recent years, the unit devices in the respective units are generally unitized and each unit can be inserted into and removed from the apparatus main body. It has become. By doing so, it becomes possible to pull out the target unit from the apparatus main body, and the workability of the maintenance work is greatly improved. As the unit, a conveyance unit provided in the conveyance unit, a transfer unit provided in the image forming unit, and a fixing unit provided in the fixing unit are generally employed.

  Each unit is usually mounted on a support frame that is detachably mounted on the apparatus main body. Therefore, each unit is exposed to the outside by pulling out the support frame from the apparatus main body, so that maintenance work for each unit can be easily performed. The support frame is formed by fixing a bottom plate made of a single metal plate between a pair of side plates by screwing or riveting.

As a unit support structure including such a support frame, for example, the one described in Patent Document 1 is known.
JP-A-9-292817

  By the way, since the bottom plate is formed flush with the support frame as described above, each unit must be arranged on the flush bottom plate so that the sheet conveying surface is located on the same plane. Such a restriction has a problem that the degree of freedom in designing each unit is lowered.

  In addition, when the bottom plate is composed of one piece, the joining piece obtained by bending the end of the bottom plate is joined to the side plate constituting the supporting frame. However, when the supporting frame is enlarged, the straightness of the joining piece can be ensured. As a result, there are problems that it takes time to join the joining pieces to the side plates, and that the side plates do not become parallel to each other, thereby hindering attachment to the support frame of each unit or the like.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an image forming apparatus capable of improving the workability of assembling work while increasing the degree of freedom in designing each unit. .

  According to the first aspect of the present invention, a conveyance unit that conveys a sheet fed from a bundle of sheets stored in a sheet storage unit, and a photosensitive drum on which a toner image is formed on the sheet conveyed by the conveyance unit. The transfer unit for transferring the toner image in cooperation with the image forming apparatus and the fixing unit for fixing the toner image to the paper subjected to the transfer process by the transfer unit can be inserted into and removed from the apparatus main body. An image forming apparatus mounted on a support frame provided in the support frame, wherein the support frame includes a pair of side plates in the width direction and a bottom plate laid between the side plates. It is characterized in that at least three of a bottom plate for a transport unit, a bottom plate for a transfer unit, and a bottom plate for a fixing unit that correspond to each unit and are independent from each other are adopted. That.

  According to such a configuration, since the transport unit, the transfer unit, and the fixing unit are all supported by the dedicated transport unit bottom plate, the transfer unit bottom plate, and the fixing unit bottom plate, the transport unit, transfer unit, and transfer unit are formed on one bottom plate. Compared to the case where the unit and the fixing unit are mounted, it becomes possible to set the height position of the bottom plate according to the size and characteristics of each unit, and this allows freedom in designing the image forming apparatus. Will improve.

  According to a second aspect of the present invention, in the first aspect of the invention, each of the bottom plates includes a flat bottom plate main body and a pair of joining pieces formed by bending each edge in the width direction of the bottom plate main body. And the joining piece is fixed to the side plate.

  According to such a configuration, the joining of the bottom plate and the side plate is facilitated by the presence of the joining piece, and the joining piece is fixed to the side plate by surface contact, so that the joining state of both is stabilized.

  According to a third aspect of the present invention, in the second aspect of the present invention, the joining piece is fixed to the side plate by welding.

  According to such a configuration, for example, by adopting a spot welding method for the welding operation, the fixing operation for both is simplified as compared with the case where the joining piece is fixed to the side plate by screwing or riveting.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, each of the bottom plates is a staircase from a lower level to a higher level in order of a conveyance unit bottom plate, a transfer unit bottom plate and a fixing unit bottom plate. It is formed in the shape.

  According to such a configuration, by appropriately setting the height difference of each bottom plate, the transport unit, the transfer unit, and the fixing unit designed for general use are respectively converted into the transport unit bottom plate, the transfer unit bottom plate, and the fixing unit bottom plate. By mounting, the height level of the sheet conveyance becomes uniform without particularly changing the unit side.

  According to the first aspect of the present invention, since the transfer unit and the fixing unit are both supported by the dedicated transport unit bottom plate, the transfer unit bottom plate, and the fixing unit bottom plate, the transport unit, Compared to the case where a transfer unit and a fixing unit are installed, the height position of the bottom plate can be set according to the size and characteristics of each unit, which gives freedom in designing the image forming apparatus. The degree can be improved and the design cost can be reduced.

  Further, in the case of a single bottom plate, when the support frame is enlarged, it is possible to ensure the straightness of the joining piece for joining to the bottom plate formed by bending the end portion of the side plate constituting the support frame. Although this makes it difficult, it takes time to join the joining pieces to the side plates, and there is a problem that the side plates do not become parallel to each other, thereby hindering attachment to the support frame of each unit or the like. In the described invention, a dedicated bottom plate is adopted for each unit, which makes it possible to make each dedicated bottom plate sufficiently smaller than a single bottom plate, so that the straightness of the joining piece is easily ensured. It is possible to ensure good parallelism between the side plates, and this will interfere with the mounting of each unit to the support frame. It is possible to reliably eliminate the convenience, and by extension can contribute to the improvement of workability of the assembling operation of the image forming apparatus.

  According to the invention described in claim 2, each bottom plate includes a flat bottom plate body and a pair of joining pieces formed by bending each edge in the width direction of the bottom plate body. With the presence of the joining piece, the bottom plate and the side plate can be easily joined, and the joining piece is fixed to the side plate by surface contact, whereby the joining state of both can be made stable and strong.

  According to the invention described in claim 3, since the joining piece is fixed to the side plate by welding, the joining piece is fixed to the side plate by screwing or riveting, for example, by adopting a spot welding method for welding work. Compared to the case, the joining operation of both can be simplified, and this can contribute to the reduction of the operation cost of the assembly operation of the image forming apparatus.

  According to the fourth aspect of the present invention, each bottom plate is formed in a step shape from the bottom to the top in the order of the bottom plate for the transport unit, the bottom plate for the transfer unit, and the bottom plate for the fixing unit. If a proper setting is made, the transport unit, transfer unit, and fixing unit designed for general use are mounted on the transport unit bottom plate, transfer unit bottom plate, and fixing unit bottom plate, respectively. Therefore, the height level of the sheet conveyance can be made uniform, and the manufacturing cost of the image forming apparatus can be reduced as much as it is not necessary to modify each unit.

  First, the outline of the internal structure of the image forming apparatus 10 according to the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view in cross-section showing an embodiment of the internal structure of an image forming apparatus 10 according to the present invention. As shown in this figure, the image forming apparatus 10 is provided with a document reading section 12 for reading a document image on the upper part of a box-shaped apparatus main body 11 and below the document reading section 12 in the apparatus main body 11. An image forming unit 13 that forms an image based on image information of a document read by the document reading unit 12 at a position, and a fixing unit 14 that performs a fixing process on the image formed by the image forming unit 13 and transferred to a sheet. And a paper storage section 15 for storing the transfer paper.

  The document reading unit 12 includes a document presser 121 provided on the upper surface of the apparatus main body 11 so as to be openable and closable, and an optical system unit 122 disposed in the apparatus main body 11 so as to face the document presser 121 via a contact glass 123. Configured. The contact glass 123 includes a contact glass 123a for a placed document having a slightly smaller planar shape than the document presser 121 for reading the document surface of the placed document, and a width direction for reading the document surface of the automatically fed document. A long and narrow automatic feeding paper contact glass 123b is provided (in a direction orthogonal to the paper surface of FIG. 1).

  An operation panel 124 is provided on the upper surface of the apparatus main body 11 on the front side of the document reading unit 12 to input processing conditions relating to document reading and copying processing. The operation panel 124 is disposed on the upper surface of the front portion of the processing apparatus main body 11 and is provided with a display panel, a numeric keypad, a start button, a mode switching key, and the like (not shown). The display panel displays various types of input information and output information on a liquid crystal display, or inputs information selected through the displayed processing conditions by a touch-in operation. The numeric keypad is mainly for setting quantity information such as the number of copies. The mode switching key is for switching the mode of the image forming apparatus 10 so that the image forming apparatus 10 can be used as a facsimile machine or a printer by a push button operation of the mode switching key. It has become.

  The document presser 121 is attached to the apparatus main body 11 so as to be able to open and close by rotating around a predetermined axis provided on one side of the upper surface of the apparatus main body. The document presser 121 has a two-stage structure, and includes a document tray 125 for placing a document provided at the upper level, and a document discharge tray 126 for discharging a scanned image document provided at the lower level. And have. A document feeding portion 127 interposed between the document tray 125 and the document discharge tray 126 is formed on the left side of the document retainer 121, and an unillustrated document feeding mechanism provided in the document feeding portion 127 is used. One document at a time is picked up from a bundle of sheets placed on the document tray 125 and supplied to the automatic feeding contact glass 123b. The picked-up document is read by the optical system unit 122 through the automatic paper feeding contact glass 123b while being moved. The original after the original image is read is discharged to the original discharge tray 126.

  The optical system unit 122 includes a light source (not shown), a plurality of mirrors, a lens unit, and a CCD (Charge Coupled device). The light from the light source is reflected by the original surface, and the reflected light is input to the CCD as original information through the mirror and the lens unit. The document information as an analog amount input to the CCD is converted into a digital signal and stored in a predetermined storage device as digital document information.

  The image forming unit 13 forms a toner image on a sheet fed from the sheet storage unit 15, and includes a photosensitive drum 131 and a developing device 132. The photosensitive drum 131 is supplied with toner from the corresponding developing device 132 while rotating clockwise in FIG.

  A charger 133 is provided at the upper left position of the photosensitive drum 131 in FIG. 1, and an exposure device 134 is provided at the upper right position. The peripheral surface of the photosensitive drum 131 is uniformly charged by the charger 133, and laser light based on image data input from the document reading unit 12 is charged from the exposure device 134 to the photosensitive drum 131 after charging. By irradiating the peripheral surface, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 131. By supplying toner from the developing device 132 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 131.

  Further, a cleaning device 135 for removing residual toner on the peripheral surface of the photosensitive drum 131 and cleaning it is provided at the lower left position of the photosensitive drum 131 in FIG. The peripheral surface of the photosensitive drum 131 cleaned by the cleaning device 135 is directed to the charger 133 for a new charging process.

  A transport belt 37 is provided below the photoconductive drum 131 so that the transport surface faces the photoconductive drum 131. The conveyor belt 37 is wound around a driving roller 35 and a driven roller 36 and is rotated by driving rotation of the driving roller 35. The paper supplied from the paper storage unit 15 is guided by the circumference of the conveyor belt 37 and moves while contacting the peripheral surface of the photosensitive drum 131, so that a transfer process is performed.

  The fixing unit 14 performs a fixing process on the toner image on the sheet transferred by the image forming unit 13, and includes a heat roller 141 and a pressure roller 142 that are arranged to face each other in the vertical direction. 140 is provided. The transfer-processed paper derived from the image forming unit 13 by the rotation of the conveyance belt 37 is fixed between the heat roller 141 and the pressure roller 142 while being pressed and heat-fixed, and the toner image is fixed. A stable color image is formed on the top. After completion of the fixing process, the sheet with the image passes through the paper discharge conveyance path 102 and is discharged toward the paper discharge tray 101 protruding from the left side wall of the apparatus main body 11.

  The paper storage unit 15 includes a plurality of paper trays 151 that are detachably attached to the apparatus main body 11. Each sheet tray 151 stores a sheet bundle. Then, the sheet P is fed out from the sheet bundle of the selected sheet tray 151 one by one by driving the pickup roller 152, and introduced into the image forming unit 13 through the sheet feeding conveyance path 153 and the registration roller pair 24. It has become.

  In the image forming apparatus 10 of the present embodiment, a sheet reversing unit 16 for performing double-sided printing on the sheet P is provided in the apparatus main body 11. The sheet reversing unit 16 is interposed between the image forming unit 13 and the sheet storage unit 15 and temporarily stores the sheet P having the image after the fixing process on one side, and the fixing unit 14. And a switching guide 162 that distributes the paper P to one of the paper discharge conveyance path 102 and the return conveyance path 103 with respect to the paper P after the fixing process, and once discharged to the intermediate tray 161. A reverse roller pair 163 that discharges the paper P from the rear end side is provided.

  The paper P once discharged to the intermediate tray 161 through the return conveyance path 103 and the reverse roller pair 163 by the switching operation of the switching guide 162 is discharged from the rear end side by the reverse rotation of the reverse roller pair 163 and is reversely conveyed. The sheet is directed to the sheet feeding / conveying path 153 through the path 104. The paper P that has been turned upside down and supplied to the paper feed conveyance path 153 is supplied again to the image forming unit 13, whereby the back side is subjected to a transfer process.

  In the present invention, the conveyance unit 20 in which the part where the registration roller pair 24 is provided in the image forming unit 13 is unitized is adopted, and the part where the conveyance belt 37 is provided is unitized. A transfer unit 30 is employed. Further, the fixing unit 40 is employed as the fixing device 140. In the present invention, a unit support frame 50 is employed as a support for the transport unit 20, the transfer unit 30, and the fixing unit 40.

  2 is a perspective view showing an embodiment of the transport unit 20, FIG. 3 is a perspective view showing an embodiment of the transfer unit 30, and FIG. 4 is a perspective view showing an embodiment of the fixing unit 40. FIG. 5 and 6 are perspective views showing an embodiment of the unit support frame 50. FIG. 5 shows a state in which the transport unit 20, the transfer unit 30, and the fixing unit 40 are not mounted. FIG. A state where the transport unit 20, the transfer unit 30, and the fixing unit 40 are mounted is shown. 2 to 6, the XX direction is referred to as the width direction, and the YY direction is referred to as the front-rear direction. In particular, the -X direction is leftward, the + X direction is rightward, the -Y direction is forward, and the + Y direction is forward. It is called the back.

  First, as illustrated in FIG. 2, the transport unit 20 includes a transport unit frame 21 including a bottom plate having a rectangular shape in plan view and a pair of side plates 22 erected from both side edges in the width direction of the bottom plate. It is configured by attaching various devices. The side plate 22 is formed such that the upper edge portion is inclined downward from the front end toward the rear end, thereby forming a triangular shape in a side view.

  The fixing device main body 21 is provided with an upstream guide plate 23 that descends backward between a pair of side plates 22 at the rear end position, and a pair of registration rollers between the pair of side plates 22 at the upper front end position. 24 is provided. In addition, an intermediate roller pair 25 is installed at the center in the front-rear direction between the pair of side plates 22, and a downstream guide plate 26 is installed between the intermediate roller pair 25 and the registration roller pair 24. Yes. The registration roller pair 24 and the intermediate roller pair 25 are configured to rotate around the axis when a driving force of a driving motor (not shown) is transmitted through a predetermined gear mechanism.

  The paper P introduced from the paper storage unit 15 to the transport unit 20 via the paper feed transport path 153 is received by the lower surface of the upstream guide plate 23, and then the intermediate roller pair 25 and the downstream guide plate 26. Further, the toner is led out toward the transfer unit 30 through the registration roller pair 24.

  The transport unit 20 is provided with an operation knob 27 that is manually operated on the left side plate 22 immediately below the intermediate roller pair 25. For example, when the paper jam occurs in the transport unit 20, this operation knob is provided. The registration roller pair 24 and the intermediate roller pair 25 are rotated by rotating the shaft 27 about the axis, whereby the jammed paper P can be taken out.

  As shown in FIG. 3, the transfer unit 30 includes a pair of side plates 32 in the width direction, an upstream erection body 33 laid between the rear end edges of the pair of side plates 32, and a erection between the front end edges. The transfer unit frame 31 formed in a rectangular shape with the downstream installation body 34 is attached with a driving roller 35, a driven roller 36 and a conveyance belt 37.

  The drive roller 35 is installed at the front end position between the pair of side plates 32, and rotates around its axis when a driving force from a drive motor (not shown) is transmitted to the roller shaft 351. The driven roller 36 is installed at a rear position between the pair of side plates 32, and the conveying belt 37 is wound around the driven roller 36 and the driving roller 35. Therefore, the driving force from the driving motor is transmitted to the conveyor belt 37 via the roller shaft 351 and the driving roller 35, and the conveyor belt 37 circulates between the driving roller 35 and the driven roller 36. .

  The upstream side erection body 33 has a sheet receiving port 331 that is long in the width direction and is opened at the rear edge. The sheet receiving port 331 is disposed so as to face the registration roller pair 24 of the transport unit 20, whereby the sheet P led out from the registration roller pair 24 is introduced into the sheet receiving port 331 of the transfer unit 30, and continues to the transport belt. It is conveyed by the upper surface side of 37. A toner image on the peripheral surface of the photosensitive drum 131 (FIG. 1) rotating in synchronization with the conveyance belt 37 is transferred onto the sheet P being conveyed by the conveyance belt 37.

  As shown in FIG. 4, the fixing unit 40 includes the heat roller 141 and the pressure roller 142 (FIG. 1) inside a fixing device main body 41 having a rectangular parallelepiped shape in the width direction. Is formed. A sheet receiving guide 42 protruding rearward is provided at a lower portion of the rear wall 411 of the fixing device main body 41, and the rear wall 411 is cut at a position directly above the front end side of the sheet receiving guide 42. A sheet receiving port 412 formed to be missing is opened. The upper surface of the rear end portion of the sheet receiving guide 42 is set at the same height level as the upper surface of the downstream installation body 34 of the transfer unit 30. Therefore, the transfer-processed sheet P conveyed by the conveyance belt 37 is smoothly transferred to the sheet receiving guide 42 of the fixing unit 40 from the upper surface of the downstream installation body 34 of the transfer unit 30.

  A connector 43 is provided on the right side wall 412 of the fixing device main body 41 so as to supply power from the power source to the heater in the heat roller 141. In addition, a driving force from a driving motor (not shown) is transmitted to the heat roller 141 and the pressure roller 142 via a predetermined gear mechanism, and the heat roller 141 and the pressure roller 142 are thereby generated. The toner image of the paper P introduced into the fixing unit 40 by synchronous rotation with the transport belt 37 is subjected to fixing processing by heating.

  As shown in FIG. 5, the unit support frame 50 includes a pair of side plates 51 in the width direction and a bottom plate (bottom plate main body) 52 provided between the pair of side plates 51. The side plate 51 is set to have a length dimension (front / rear length) slightly longer than the front / rear length of the transport unit 20, the transfer unit 30 and the fixing unit 40, and protrudes upward from the other at the left end. It has a portion 511, and thereby has an overall L shape.

  In the present embodiment, the bottom plate 52 is provided on the most upstream side between the side plates 51 and is provided on the downstream side of the transport unit bottom plate 53 and the transport unit bottom plate 53 for supporting the transport unit 20. A transfer unit bottom plate 54 for supporting the transfer unit 30 and a fixing unit bottom plate 55 for supporting the fixing unit 40 provided immediately downstream of the transfer unit bottom plate 54 are employed. ing.

  Of these bottom plates 53, 54, and 55, the transport unit bottom plate 53 is provided at the lowest position, and the transfer unit bottom plate 54 is provided slightly above the transport unit bottom plate 53. Further, the fixing unit bottom plate 55 is provided at a higher level than the transfer unit bottom plate 54, whereby the bottom plates 53, 54, 55 are stepped.

  Such a unit support frame 50 has various mounting holes and mounting projections provided to fix the units 20, 30, 40 at appropriate positions of the side plates 51 and the bottom plates 53, 54, 55. Positioning is performed by fitting the protrusions and holes of the units 20, 30, and 40 corresponding to the mounting holes and mounting protrusions in a state where the units 20, 30, and 40 are placed on the corresponding bottom plates 53, 54, and 55. In this state, binding processing such as screwing and clamping is performed, so that the mounting state of the units 20, 30, and 40 on the unit support frame 50 is reliably maintained.

  Further, a pair of joining pieces 521 formed by bending upward are provided at both edges in the width direction of the bottom plates 53, 54, 55. In the present embodiment, these joining pieces 521 are provided as a pair. Each bottom plate 53, 54, 55 is fixed to the side plate 51 by being joined to the side plate 51 by spot welding. By fixing the joining piece 521 to the side plate 51 by such spot welding, the working efficiency is improved as compared with the case of screwing or riveting.

  An upstream angle member 56 is installed between the rear edges of the pair of side plates 51 in the unit support frame 50, and a downstream angle member 57 is installed between the upper positions of the front edges. . These angle members 56 and 57 are supported by a pair of front and rear rail members 105 (FIG. 6) disposed in the apparatus main body 11 and extending in the width direction. By being supported by the rail member 105, the unit support frame 50 can be pulled out from the apparatus main body 11 toward the operator.

  In the state where each unit 20, 30, 40 is mounted on the unit support frame 50, each unit 20, 30, 40 has a bottom plate 53, 54, 55 formed in a step shape according to the three-dimensional shape. Therefore, as shown in FIG. 6, the conveyance surface of the paper P is flush with the downstream side of the pair of registration rollers 24 in these units 20, 30, and 40, thereby conveying the paper P. Will be performed smoothly.

  As described above in detail, the image forming apparatus 10 of the present invention has been transported by the transport unit 20 that transports the paper P fed from the paper bundle stored in the paper storage unit 15 and the transport unit 20. The transfer unit 30 that performs transfer processing of the toner image in cooperation with the photosensitive drum 131 on which the toner image is formed on the paper P, and the toner image on the paper P that has been transferred by the transfer unit 30. A fixing unit 40 that performs a fixing process is mounted on a unit support frame 50 that is detachably attached to the apparatus main body 11. The unit support frame 50 includes a pair of side plates 51 in the width direction, The bottom plate 52 is provided between the side plates 51. The bottom plate 52 corresponds to each unit and is independent from each other, and includes a transport unit bottom plate 53 and a transfer unit. Preparative bottom plate 54 and the fixing unit for the bottom plate 55 is employed.

  Accordingly, since the transport unit 20, the transfer unit 30, and the fixing unit 40 are all supported by the dedicated transport unit bottom plate 53, the transfer unit bottom plate 54, and the fixing unit bottom plate 55, the transport unit is formed on a single bottom plate. 20, the height position of the bottom plate can be set according to the size and characteristics of each unit 20, 30, 40 as compared with the case where the transfer unit 30 and the fixing unit 40 are mounted. The degree of freedom in designing the forming apparatus can be improved, and the design cost can be reduced.

  Further, each of the bottom plates 53, 54, 55 is formed in a flat plate shape, and a pair of joining pieces 521 formed by bending each edge portion of the flat plate-like bottom plates 53, 54, 55 in the width direction is provided. Since each joining piece 521 is fixed to the side plate 51, the bottom plate 52 and the side plate 51 can be easily coupled to each other by the presence of the joining piece 521, and the joining piece 521 is fixed to the side plate 51 by surface contact. By doing so, the joining state of both can be made stable and strong.

  In addition, since the joining piece 521 is fixed to the side plate 51 by welding, for example, a spot welding method is adopted for welding work, so that the joining piece 521 is fixed to the side plate 51 with screws or rivets. The joining operation between the two can be simplified, thereby contributing to a reduction in the operation cost of the assembly operation of the image forming apparatus.

  Further, each of the bottom plates 53, 54, 55 is formed in a step shape from the lower level to the higher level in the order of the conveyance unit bottom plate 53, the transfer unit bottom plate 54 and the fixing unit bottom plate 55. , 55 are set appropriately, the transport unit 20, the transfer unit 30, and the fixing unit 40 designed for general use are mounted on the transport unit bottom plate 53, the transfer unit bottom plate 54, and the fixing unit bottom plate 55, respectively. By doing so, the height level of the conveyance of the paper P can be made uniform without adding any special hand to the unit side, and the image forming apparatus can be made to the extent that the units 20, 30, and 40 need not be changed. This can contribute to a reduction in manufacturing costs.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above-described embodiment, the bottom plate 52 employs three sheets, that is, the transport unit bottom plate 53, the transfer unit bottom plate 54, and the fixing unit bottom plate 55. It is not limited to being a sheet, and may be four or more. Further, if a bottom plate is further provided below the bottom plates 53, 54, and 55 to form a double structure, and the lower bottom plate is used as an intermediate tray of the sheet reversing unit 16, a dedicated intermediate tray 161 needs to be provided in the apparatus main body 11. This contributes to a reduction in equipment costs.

  (2) In the above embodiment, the joining piece 521 of each bottom plate 53, 54, 55 is fixed to the side plate 51 by welding stop. However, in the present invention, each bottom plate 53, 54, 55 is welded stop. It is not limited to being fixed to the side plate 51, and may be fixed by screwing or riveting.

  (3) In the above embodiment, a copying machine is employed as the image forming apparatus 10, but the present invention is not limited to the image forming apparatus being a copying machine. It may be a printer connected to the printer.

  (4) In the above embodiment, the image forming apparatus 10 is for monotone printing, but the present invention is not limited to the image forming apparatus 10 for monotone printing. It may be for color printing.

1 is a schematic explanatory view in cross-sectional view showing an embodiment of an internal structure of an image forming apparatus according to the present invention. It is a perspective view which shows one Embodiment of a conveyance unit. It is a perspective view which shows one Embodiment of a transfer unit. FIG. 3 is a perspective view showing an embodiment of a fixing unit. It is a perspective view showing one embodiment of a unit support frame, and shows the state where a conveyance unit, a transfer unit, and a fixing unit are not attached. It is a perspective view showing one embodiment of a unit support frame, and shows a state where a conveyance unit, a transfer unit, and a fixing unit are attached.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 101 Image forming apparatus 102 Paper discharge conveyance path 103 Return conveyance path 104 Reverse conveyance path 105 Rail member 11 Main body 12 Document reading part 121 Document pressing 122 Optical system unit 123 Contact glass 123a Placed document contact glass 123b Automatic Contact glass 124 for feeding paper Operation panel 125 Document tray 126 Document discharge tray 127 Document feeding section 13 Image forming section 131 Photosensitive drum 132 Developing device 133 Charger 134 Exposure device 14 Fixing section 141 Heat roller 142 Pressure roller 15 Sheet storage Section 151 Paper tray 152 Pickup roller 153 Paper feed path 154 Registration roller 16 Paper reversing section 161 Intermediate tray 162 Switching guide 163 Reverse roller pair 20 Transport unit 21 Transport unit frame 2 Side plate 23 Upstream guide plate 24 Registration roller pair 25 Intermediate roller pair 26 Downstream guide plate 27 Operation knob 30 Transfer unit 31 Transfer unit frame 32 Side plate 33 Upstream installation body 331 Paper receiving entrance 34 Downstream installation body 35 Drive roller 351 Roller shaft 36 Followed roller 37 Conveying belt 40 Fixing unit 41 Fixing device main body 411 Rear wall 412 Side wall 42 Paper receiving guide 43 Connector 50 Unit support frame 51 Side plate 511 Standing portion 52 Bottom plate (bottom plate main body) 521 Joining piece 53 Bottom plate for conveyance unit 54 Transfer Unit Bottom Plate 55 Fixing Unit Bottom Plate 56 Upstream Angle 57 Downstream Angle Material P Paper

Claims (4)

The toner image is formed in cooperation with a conveyance unit that conveys a sheet fed from a bundle of sheets stored in the sheet storage unit, and a photosensitive drum on which a toner image is formed on the sheet conveyed by the conveyance unit. A transfer unit for performing the transfer process and a fixing unit for fixing the toner image to the paper subjected to the transfer process by the transfer unit are mounted on a support frame that is detachable from the apparatus main body. An image forming apparatus comprising:
The support frame includes a pair of side plates in the width direction and a bottom plate constructed between the side plates,
2. The image forming apparatus according to claim 1, wherein at least three of the bottom plate corresponding to each unit and independent from each other, a bottom plate for a transfer unit, a bottom plate for a transfer unit, and a bottom plate for a fixing unit are employed.   Each of the bottom plates includes a flat bottom plate body and a pair of joining pieces formed by bending each edge portion in the width direction of the bottom plate body, and the joining pieces are fixed to the side plates. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 2, wherein the joining piece is fixed to the side plate by welding.   4. The method according to claim 1, wherein each of the bottom plates is formed in a step shape from a low level to a high level in order of a conveyance unit bottom plate, a transfer unit bottom plate, and a fixing unit bottom plate. Image forming apparatus.

Images