Image forming apparatus

Abstract

To provide an image forming apparatus that includes a plurality of dividable frame bodies.SOLUTION: An image forming apparatus comprises three structures which are: a supply block, an image forming block, and an ejection block, which are dividable. The supply block, the image forming block, and the ejection block have a supply frame body 100e, an image forming frame body 100f, and an ejection frame body 100g, respectively, and various units and components are assembled inside the frame bodies. An apparatus body of the image forming apparatus is assembled by laminating the supply block, image forming block, and ejection block, and the image forming block is supported on the supply block at three points with the image forming frame body 100f therebetween. The ejection block is supported on the image forming block at three points with the image ejection frame body 100g therebetween.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile machine, or a multifunction machine. [Background technology]

[0002] In conventional image forming devices, a single main body frame is formed by combining multiple metal plates and integrating them with screws or welding (Patent Document 1). Various units are then supported on the single main body frame. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-39153 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present application have discovered that conventional techniques for assembling various units into a single main body frame have problems. For example, it is difficult to expand the functionality of an image forming apparatus. It is sometimes desirable to replace some units of an image forming apparatus with units that have different functions. However, a single main body frame, as in the past, is designed to support a specific unit. As a result, it is often impossible to replace some units with other units. Another example is when multiple image forming apparatuses with different specifications are required to meet various user needs. In the case of an image forming apparatus with a single main body frame, the main body frame must be designed from scratch to suit each individual specification. This creates a burden in development, design, and manufacturing.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an image forming apparatus including a plurality of separable frames. [Means for solving the problem]

[0006] An image forming apparatus according to one embodiment of the present invention is an image forming apparatus that forms an image on a recording material, and is characterized in that it comprises a first block having a first frame, a transfer member for transferring a toner image to the recording material, and a first transport path along which the recording material is transported, a second frame arranged above the first frame so as to be separable from the first frame, a second transport path along which the recording material is transported from the first transport path, and a discharge section that discharges the recording material transported on the second transport path to the outside, and the first block is supported at three points, and the second block is supported at three points relative to the first block. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an image forming apparatus including a plurality of separable frames. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus. [Figure 2] 1A is a schematic diagram showing a discharge frame, FIG. 1B is a schematic diagram showing an imaging frame, and FIG. 1C is a schematic diagram showing a supply frame. [Figure 3] Schematic diagram showing support points for each block. [Figure 4] FIG. 4 is a schematic diagram showing the position of the third support point of the imaging frame and the connecting support pillar. [Figure 5] 1A is a schematic diagram showing the positional relationship of support points in a discharge block, FIG. 1B is a schematic diagram showing the positional relationship of support points in an image forming block, and FIG. 1C is a schematic diagram showing the positional relationship of support points in a supply block. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] <Image forming device> The present embodiment will be described below. First, the schematic configuration of the image forming apparatus of this embodiment will be described using FIG. 1. Note that the terms "front" and "rear" used in the following description refer to the front side of the image forming apparatus and the rear side of the apparatus, and "right" and "left" correspond to the apparatus as viewed from the front side. The front side of the apparatus is the side where the user operates the apparatus, such as the side where the operation panel is located or the side where the cassette containing the recording material is pulled out. The "vertical direction" refers to the vertical direction when the image forming apparatus is installed on an installation surface such as the floor. FIG. 1 shows the image forming apparatus 1 as viewed from the front side.

[0010] The image forming apparatus 1 shown in FIG. 1 is an intermediate transfer type full-color printer. Four color image forming stations PY, PM, PC, and PK that form toner images of yellow (Y), magenta (M), cyan (C), and black (K) are arranged facing an intermediate transfer belt 21. The image forming apparatus 1 includes an image forming unit 500. The image forming unit 500 forms a toner image on a recording material S based on an image signal received from a document reading unit 30 or an external terminal (not shown) such as a personal computer. The image forming unit 500 includes the image forming stations PY, PM, PC, and PK and an intermediate transfer unit 600.

[0011] The document reading unit 30 disposed on the device main body 1A has a document transport section and an image reading section, although not shown. The document transport section is provided so that its front side can be opened and closed relative to the image reading section. The user can load the document from which the image is to be read onto the document transport section. When the document transport section is closed, the document can be automatically transported one sheet at a time to the image reading section. The image reading section has a document tray and a reading sensor, and the reading sensor reads the image of the document placed one sheet at a time on the document tray. Note that the user can place the document on the document tray with the document transport section open, and can also close the document transport section with the document placed on the document tray and have the reading sensor read the image of the document.

[0012] The conveyance process of the recording material S in the image forming apparatus 1 will be described. The recording material S is stored in a stacked state in a cassette 31 serving as a storage body. Conveyance of the recording material S is initiated by a supply unit 300 serving as a supply section. The supply unit 300 has a supply roller 31a. The recording material S is supplied one sheet at a time from the cassette 31 to a conveyance path 60 by the supply roller 31a in accordance with the image formation timing. In the image forming apparatus 1 of this embodiment, the conveyance path 60 is arranged so that the recording material S can be conveyed from below upward (a so-called vertical conveyance method). Note that the recording material S may be any of a variety of sheet materials, such as plain paper, cardboard, rough paper, textured paper, coated paper, plastic film, cloth, etc.

[0013] The recording material S supplied from the cassette 31 to the conveying path 60 is conveyed to a pre-registration roller pair 41 disposed midway along the conveying path 60. The pre-registration roller pair 41 and the registration roller pair 42 correct skew of the recording material S. Specifically, the leading edge of the recording material S conveyed by the pre-registration roller pair 41 strikes the nip portion of the stationary registration roller pair 42. As the leading edge of the recording material S is aligned with the nip portion of the registration roller pair 42, the recording material S loops or bends, thereby correcting skew. After skew correction, the registration roller pair 42 starts rotating in synchronization with the secondary transfer timing to convey the recording material S. The intermediate transfer belt 21 and the secondary transfer unit are disposed above the registration roller pair 42, which serves as a conveying rotating body. The registration roller pair 42 conveys the recording material S from below to above the secondary transfer unit in synchronization with the timing at which the toner image on the intermediate transfer belt 21 is transferred to the recording material S (secondary transfer timing). The registration roller pair 42 is disposed at a position closest to the secondary transfer portion on the upstream side of the secondary transfer portion in the conveying direction (vertical direction) of the recording material S conveyed along the conveying path 60. The secondary transfer portion is composed of a secondary transfer inner roller 22 and a secondary transfer outer roller 44. The secondary transfer inner roller 22 and the secondary transfer outer roller 44 (second transfer member, secondary transfer member) face each other with the intermediate transfer belt 21, which serves as a transfer member (first transfer member, intermediate transfer body), sandwiched between them. The secondary transfer portion (secondary transfer inner roller 22 and secondary transfer outer roller 44) forms a nip portion, and a toner image is transferred from the intermediate transfer belt 21 onto the recording material S by applying a predetermined pressure and secondary transfer voltage.

[0014] The process of forming an image sent to the secondary transfer unit at the same timing as the process of conveying the recording material S to the secondary transfer unit described above will now be described. First, the image forming units PY to PK will be described. However, since the image forming units PY to PK for each color are basically the same except for the color of the toner, the following description will be made using the yellow image forming unit PY as an example.

[0015] The image forming unit PY has a photosensitive drum 11Y as a photosensitive member, a charger 12Y as a charging unit, an exposure unit 13Y as an exposure unit, and a developing unit 14Y as a developing unit. The surface of the photosensitive drum 11Y, which is driven to rotate, is uniformly charged in advance by the charger 12Y, and then an electrostatic latent image is formed on the surface by laser light irradiated from the exposure unit 13Y, which is driven based on an image signal. The electrostatic latent image formed on the photosensitive drum 11Y is then developed into a toner image by the developing unit 14Y. The developing unit 14Y develops the electrostatic latent image into a toner image using a developer containing toner and carrier. Note that toner is consumed during development, and toner is replenished to the developing unit 14Y at appropriate times from a toner bottle (not shown) containing replenishment toner.

[0016] A primary transfer voltage is applied to the toner image formed on the photosensitive drum 11Y (photoconductor) by a primary transfer roller 25Y disposed opposite the photosensitive drum 11Y with the intermediate transfer belt 21 sandwiched therebetween, and the toner image is primarily transferred from the photosensitive drum 11Y to the intermediate transfer belt 21. Any residual toner remaining on the photosensitive drum 11Y after the primary transfer is removed by a photosensitive drum cleaner.

[0017] The intermediate transfer belt 21 is an endless belt stretched by a secondary transfer inner roller 22, a drive roller 23, a tension roller 24, and the like, and moves in the direction of arrow A in the figure. That is, the intermediate transfer belt 21 is configured in a circular shape. The tension roller 24 is a driven rotor that applies tension to the intermediate transfer belt 21 and rotates following the movement of the intermediate transfer belt 21 by the drive roller 23. The image formation processes for each color, which are processed in parallel by the image forming units PY to PK described above, are performed at a timing that sequentially superimposes the color toner images that were primarily transferred onto the intermediate transfer belt 21 upstream in the movement direction. As a result, a full-color toner image is finally formed on the intermediate transfer belt 21, and the toner image is transported to the secondary transfer unit as the intermediate transfer belt 21 moves. In this embodiment, the primary transfer rollers 25Y to 25K, the intermediate transfer belt 21, the secondary transfer inner roller 22, the drive roller 23, and the tension roller 24 are integrally configured as an intermediate transfer unit 600. However, the technology of the present disclosure is not limited to such a configuration.

[0018] Through the conveying process and image forming process described above, the timing of the recording material S and the full-color toner image are synchronized at the secondary transfer unit, and secondary transfer is performed, in which the toner image is transferred from the intermediate transfer belt 21 to the recording material S. Any residual toner remaining on the intermediate transfer belt 21 after passing through the secondary transfer unit is removed from the intermediate transfer belt 21 by a belt cleaner. The recording material S with the transferred toner image is conveyed along a conveying path 60 to the fixing device 50, where the toner image is fixed to the recording material S by applying heat and pressure. The fixing device 50 has a fixing roller heated by a heater (not shown) and a pressure roller that contacts the fixing roller and forms a fixing nip. The fixing device 50 applies heat and pressure to the recording material S passing through the fixing nip, thereby fixing the toner image to the recording material S. The recording material S with the toner image fixed by the fixing device 50 is conveyed further up the conveying path 60 and discharged to the outside by a discharge unit 700. The discharge unit 700 has a discharge roller 61 , and the recording material S is discharged by the discharge roller 61 and stacked on a discharge tray 81 .

[0019] An operation panel 40 having a display capable of displaying various information and keys for inputting various information in response to user operation is disposed facing the front of the device body 1A of the image forming device 1. A user can use the operation panel 40 to make various settings when operating the image forming device 1. For example, when making copies, the user can use the operation panel 40 to make settings such as the number of sheets of recording material S to be copied, the size of the recording material S to be copied, the cassette storing the recording material S to be copied, enlargement / reduction of the copy image, image density, double-sided / single-sided copying, color / black and white copying, etc.

[0020] <Device body> Next, the apparatus main body 1A of this embodiment will be described. In this embodiment, the apparatus main body 1A (structure) is divided into three separable structures: a supply block 110, an imaging block 120, and a discharge block 130. Note that the term "structure" as used herein refers to a state in which various units and components are assembled to a frame formed by pillars, stays (beams), etc. The state in which various units and components are assembled to a frame is, in other words, a state in which the various units and components are supported by the frame. The supply block 110, the imaging block 120, and the discharge block 130 each have a supply frame 100e, an imaging frame 100f, and a discharge frame 100g, as described below. To enable the three structures to be separated, the supply frame 100e, the imaging frame 100f, and the discharge frame 100g are configured to be separable from each other.

[0021] In this embodiment, the apparatus main body 1A, which realizes a series of functions for forming an image on the recording material S, is configured such that an imaging block 120 is stacked on top of a supply block 110, and a discharge block 130 is stacked on top of the imaging block 120. Although not shown in the figures, the stacked imaging block 120 and discharge block 130 are connected by, for example, a metal plate-like member (connecting member) that is hung between support columns located above and below and fastened with screws. The supply block 110 and the imaging block 120 are also connected by a connecting member in a similar manner.

[0022] <Supply block, imaging block, discharge block> The supply block 110, which serves as the third block, is a structure in which a supply unit 300 and a supply conveying path 610 are assembled to a supply frame 100e (described later). Rail members (not shown) that support the cassette 31 so that it can slide forward and backward are also assembled to the supply block 110. The imaging block 120, which serves as the first block, is a structure in which an image forming unit 500 having an intermediate transfer unit 600 and an image forming conveying path 620 are assembled to an imaging frame 100f (described later). The image forming unit 500 may be detachably attached to the imaging frame 100f. The discharge block 130, which serves as the second block, is a structure in which a discharge unit 700, a discharge conveying path 630, and a fixing device 50 are assembled to a discharge frame 100g (described later).

[0023] In this embodiment, a conveying path 60 that conveys the recording material S from below upward is divided and formed in each of the supply block 110, the imaging block 120, and the discharge block 130. That is, a supply conveying path 610 as a third conveying path forms a part of the conveying path 60 in the supply block 110, an imaging conveying path 620 as a first conveying path forms a part of the conveying path 60 in the imaging block 120, and a discharge conveying path 630 as a second conveying path forms a part of the conveying path 60 in the discharge block 130. The supply conveying path 610 conveys the recording material S from the cassette 31 toward the imaging conveying path 620, and the discharge conveying path 630 conveys the recording material S from the imaging conveying path 620.

[0024] <Discharge frame, imaging frame, supply frame> The discharge frame 100g, imaging frame 100f, and supply frame 100e will now be described with reference to FIGS. 2(a) to 2(c). As shown in FIG. 2(a), the discharge frame 100g, serving as the second frame, includes a right front support column 114ga, a rear plate 115g, an upper right stay 113ga, a lower right stay 113gb, a left stay 113gc, and a front stay 113gd. The right front support column 114ga extends vertically. The upper right stay 113ga and the lower right stay 113gb are aligned vertically with respect to the right front support column 114ga and arranged substantially parallel to each other, connecting the right front support column 114ga and the rear plate 115g. The left stay 113gc is arranged substantially perpendicular to the rear plate 115g so as to face the lower right stay 113gb and be substantially parallel to it. The front stay 113gd is disposed in a direction parallel to the rear side plate 115g (in the left-right direction) so as to connect the left stay 113gc and the right front support pillar 114g.

[0025] The discharge frame body 100g also includes a front support 114gb, an upper stay 113ge, and an upper right stay 113gf. The front support 114gb is disposed between the left stay 113gc and the lower right stay 113gb, to the right of the center of the front stay 113gd in the left-right direction, and is disposed substantially parallel to the right front support 114ga. The front support 114gb is connected to the front stay 113gd. The upper stay 113ge is disposed substantially parallel to the upper right stay 113ga so as to connect the front support 114gb to the rear side plate 115g. The upper right stay 113gf is disposed substantially parallel to the front stay 113gd so as to connect the right front support 114ga to the front support 114gb. The discharge unit 700 described above is installed in the space secured by these 114ga, 114gb, 113ga, 113gb, 113ge, 113gf and rear side plate 115g.

[0026] As shown in FIG. 2(b), the imaging frame 100f, which serves as the first frame, includes a right front support column 114fa, a left front support column 114fb, a rear side plate 115f, an upper right stay 113fa, a lower right stay 113fb, an upper left stay 113ff, a lower left stay 113fc, an upper front stay 113fe, and a lower front stay 113fd. The right front support column 114fa extends vertically. The upper right stay 113fa and the lower right stay 113fb are aligned vertically with respect to the right front support column 114fa and arranged substantially parallel to each other, connecting the right front support column 114fa and the rear side plate 115f. The left front support column 114fb extends vertically so as to face the right front support column 114fa and be substantially parallel to each other. The upper-left stay 113ff and the lower-left stay 113fc are arranged vertically and generally parallel to each other relative to the left front support column 114fb, connecting the left front support column 114fb to the rear side plate 115f. The upper-front stay 113fe is arranged in a direction parallel to the rear side plate 115f (left-right direction) so as to connect the right front support column 114fa to the left front support column 114fb at their upper ends. The lower-front stay 113fd is arranged in a direction parallel to the rear side plate 115f (left-right direction) so as to connect the right front support column 114fa to the left front support column 114fb at their lower ends. To ensure the strength of the imaging frame 100f as a frame body, reinforcing members 1151 corresponding to the supports provided on the right front support column 114fa, the left front support column 114fb, and the rear side plate 115f are arranged at the four corners of the frame body. The reinforcing members 1151 are provided on both left and right ends of the rear plate 115f.

[0027] As shown in FIG. 2(c), the supply frame 100e, which serves as the third frame, includes a right front support column 114ea, a left front support column 114eb, a rear side plate 115e, an upper right stay 113ea, a lower right stay 113eb, an upper left stay 113ef, a lower left stay 113ec, an upper front stay 113ee, and a lower front stay 113ed. The right front support column 114ea extends vertically. The upper right stay 113ea and the lower right stay 113eb are aligned vertically with respect to the right front support column 114ea and arranged substantially parallel to each other, connecting the right front support column 114ea to the rear side plate 115e. The left front support column 114eb extends vertically so as to face the right front support column 114ea and be substantially parallel to it. The upper-left stay 113ef and the lower-left stay 113ec are arranged vertically and generally parallel to each other relative to the left front support column 114eb, and connect the left front support column 114eb to the rear side plate 115e. The upper-front stay 113ee is arranged in a direction parallel to the rear side plate 115g (left-right direction) so as to connect the right front support column 114ea to the left front support column 114eb at their upper ends. The lower-front stay 113ed is arranged in a direction parallel to the rear side plate 115e (left-right direction) so as to connect the right front support column 114ea to the left front support column 114eb at their lower ends. In the vertical direction, the connection position of the upper-right stay 113ea to the right front support column 114ea and the connection position of the upper-left stay 113ef to the left front support column 114eb are lower than the connection positions of the upper-front stay 113ee to the right front support column 114ea and the left front support column 114eb. To ensure the strength of the supply frame 100e, reinforcing members 1152 corresponding to the supports provided on the right front support 114ea, the left front support 114eb, and the rear side plate 115e are disposed at the four corners of the frame. The reinforcing members 1152 are provided at both left and right ends of the rear side plate 115e.

[0028] In this way, the apparatus main body 1A can be assembled by dividing it into the supply block 110, the imaging block 120, and the discharge block 130. The supply frame 100e of the supply block 110 is attached below the imaging frame 100f of the imaging block 120 so as to be separable from it. The discharge frame 100g of the discharge block 130 is attached above the imaging frame 100f of the imaging block 120 so as to be separable from it. In this way, it is only necessary to assemble units and parts for each of the supply block 110, the imaging block 120, and the discharge block 130, which allows for a significant reduction in the number of steps required to assemble the apparatus main body 1A and also improves the product quality of the apparatus main body 1A. Furthermore, since it is easy to divide the device main body 1A into a supply block 110, an imaging block 120, and a discharge block 130, and to add and assemble units that realize new functions (such as a second fixing unit) to the supply frame body 100e, the imaging frame body 100f, and the discharge frame body 100g, it is easy to expand the functions of the image forming device 1.

[0029] <Block support structure> Next, the support configuration of the supply block 110, the imaging block 120, and the discharge block 130 in this embodiment will be described using FIGS. 3 to 5(c) with reference to FIGS. 1, 2(a), 2(b), and 2(c). In this embodiment, as shown in FIG. 3, the imaging block 120 is supported at three points (101f, 102f, 103f) relative to the supply frame 100e via the imaging frame 100f. The discharge block 130 is supported at three points (101g, 102g, 103g) relative to the imaging frame 100f via the discharge frame 100g. Furthermore, the supply block 110 is supported at three points (101e, 102e, 103e) relative to the installation surface, such as a floor or a desk, via the supply frame 100e. Although not shown in the figure, the discharge frame 100g, the imaging frame 100f, and the supply frame 100e each have support portions that protrude downward at three locations, and these support portions provide support at three points (101, 102, 103).

[0030] However, if the device main body 1A can be divided into the supply block 110, the imaging block 120, and the discharge block 130, and the support structure for the supply block 110, the imaging block 120, and the discharge block 130 is not three-point support, problems will arise regarding the positional accuracy of the units and parts attached to the device main body 1A. Two specific examples of these problems will be given below.

[0031] The first challenge is ensuring the flatness of the intermediate transfer belt 21. Because the intermediate transfer belt 21 moves while stretched across multiple rollers (22, 23, 24), if the flatness of the intermediate transfer belt 21 cannot be maintained at a certain level, the difference in frictional resistance between the intermediate transfer belt 21 and the rollers (22, 23, 24) will cause distortion of the intermediate transfer belt 21, resulting in poor transfer. Furthermore, the difference in frictional resistance will cause a force to move the intermediate transfer belt 21 in the direction of its axis of rotation, for example, at the drive roller 23. Therefore, a regulating member or a centering mechanism (also called a steering mechanism) is provided to regulate the so-called "belt deviation," which causes the intermediate transfer belt 21 to deviate toward one end of the drive roller 23. However, if the force to move the intermediate transfer belt 21 is too great, it is difficult to return the intermediate transfer belt 21 to its predetermined position in the direction of its axis of rotation, which could lead to breakdowns such as tearing of the intermediate transfer belt 21.

[0032] One of the reasons why the flatness of the intermediate transfer belt 21 cannot be maintained is distortion of the device body caused by the unevenness of the installation surface on which the image forming device 1 is installed. In the case of four-point support, the unevenness of the installation surface may cause one of the four points to not contact the installation surface. In this case, the load on the one point that is not in contact may cause the frame to deform. The deformation of the frame ultimately leads to a decrease in the positional accuracy of the units and parts attached to the frame.

[0033] Therefore, in the image forming apparatus of this embodiment, the apparatus main body 1A is supported at three points to reduce the effect of unevenness on the installation surface, and the rigidity of the main body frame above the support points ensures the relative positions of the units assembled to the main body frame. More specifically, by supporting the supply frame 100e on the installation surface at three points (101e, 102e, 103e), the effect of unevenness on the installation surface on the supply frame 100e is reduced.

[0034] Furthermore, in this embodiment, a configuration is adopted in which the imaging frame 100f (and the discharge frame 100g) can be separated from the supply frame 100e. Therefore, distortion of the imaging frame 100f must also be taken into consideration. One solution to the distortion of the imaging frame 100f is, for example, a four-point support configuration in which the supply frame 100e and the imaging frame 100f are fastened together near the four corners. By fastening the frames together near the four corners, the rigidity of the supply frame 100e and the imaging frame 100f can ensure the relative positions of the units assembled to the frames.

[0035] However, when the supply frame 100e and the imaging frame 100f are supported at four points, the support surface of the supply frame 100e and the supporting portion of the imaging frame 100f are easily affected by the component tolerances. The required precision for the flatness of the intermediate transfer belt 21 is high, and the effect of such component tolerances cannot be ignored, so there is room for further improvement in the above-described four-point support configuration.

[0036] Therefore, in this embodiment, as shown in FIG. 3, a three-point support configuration is adopted in which the imaging frame 100f is supported on the supply frame 100e at three points (101f, 102f, 103f). The imaging frame 100f is supported on the supply frame 100e at three points: the first support point 101f, the second support point 102f, and the third support point 103f. Supporting the imaging frame 100f at three points (101f, 102f, 103f) can reduce the influence of the unevenness of the installation surface, the influence of distortion of the imaging frame 100f, and the influence of component tolerances. The supply frame 100e is supported on the installation surface at three points: the fourth support point 101e, the fifth support point 102e, and the sixth support point 103e. The discharge frame 100g is supported at three points, ie, a seventh supporting point 101g, an eighth supporting point 102g, and a ninth supporting point 103g, relative to the imaging frame 100f.

[0037] The second issue is ensuring the alignment of pairs of rollers that sandwich and transport the recording material S along the divided supply transport path 610, image creation transport path 620, and discharge transport path 630 (see FIG. 1). Ensuring alignment here means ensuring that there is no misalignment between the pair of rollers in the direction of their rotational axes. If there is misalignment between the pair of rollers in the direction of their rotational axes, the transport distance and sliding resistance of the recording material S will differ, which could cause the recording material S to skew, leading to a decrease in image position quality on the finished product, such as geometric characteristics like a left margin. Misalignment between the pair of rollers in the direction of their rotational axes can occur due to misalignment between the frames in the left-right and up-down directions.

[0038] In this embodiment, a three-point support configuration is adopted to solve the first problem. While the support points can regulate the vertical, horizontal, and lateral positions, freedom of positioning is required at the other support points to ensure the desired flatness of the intermediate transfer belt 21. Therefore, as shown in FIG. 3, two of the three support points (101 and 102) are arranged in the vertical and horizontal directions on the conveyance path 60 side (conveyance path side) of each block. Specifically, the first support point 101f and the second support point 102f of the imaging frame 100f are located closer to the image conveyance path 620 than the center of the imaging block 120 when viewed from above (see FIG. 1). The fourth support point 101e and the fifth support point 102e of the supply frame 100e are located closer to the supply conveyance path 610 than the center of the supply block 110 when viewed from above. Furthermore, the seventh support point 101g and the eighth support point 102g of the discharge frame 100g are located closer to the discharge transport path 630 than the center of the discharge block 130 when the discharge block 130 is viewed from above.

[0039] In this way, by supporting two of the three support points (101, 102) in a line in the front-to-rear direction on the conveying path 60 side of each block, it is possible to ensure the vertical positional relationship. As a result, in a vertical conveying method in which the recording material S is conveyed from the bottom to the top, even if the device main body 1A is configured as a division of multiple blocks (110, 120, 130), distortion is unlikely to occur in the series of conveying paths 60 (vertical path conveying paths) in the device main body 1A. Therefore, it is possible to suppress misalignment (alignment error) in the rotation axis direction between a pair of rollers that convey the recording material S.

[0040] The supply frame 100e, the imaging frame 100f, and the discharge frame 100g each have high-strength support columns (114ea, 114eb, 114fa, 114fb, 114ga) and reinforcing members (1152, 1151, 1150) (see FIGS. 2(a) to 2(c)). The first support point 101f of the imaging frame 100f is located on the right front support column 114fa, and the second support point 102f of the imaging frame 100f is located on the reinforcing member 1151 on the right side of the rear plate 115f. The fourth support point 101e of the supply frame 100e is located on the right front support column 114ea, and the fifth support point 102e of the supply frame 100e is located on the reinforcing member 1152 on the right side of the rear plate 115e. Furthermore, the seventh support point 101g of the discharge frame body 100g is disposed on the right front support pillar 114ga, and the eighth support point 102g of the discharge frame body 100g is disposed on a reinforcing member 1150 on the right side of the rear side plate 115g. When the image forming apparatus 1 is viewed from above, it is preferable that the two support points (101, 102) are disposed so that the seventh support point 101g, the first support point 101f, and the fourth support point 101e overlap, and the eighth support point 102g, the second support point 102f, and the fifth support point 102e overlap. In this way, the two support points (101, 102) on the conveyance path 60 side of each block are disposed on high-strength support pillars and reinforcing members, and these support pillars and reinforcing members ensure the strength of the supported surfaces (seating surfaces) that support the two support points (101, 102).

[0041] On the other hand, the remaining one of the three support points (103) is located on the opposite side of the conveying path 60 in the left-right direction, as shown in FIG. 3. Specifically, the third support point 103f of the imaging frame 100f is located on a lower left stay 113fc (see FIG. 2(b)) on the opposite side of the image conveying path 620 (see FIG. 1) from the center of the imaging block 120 when viewed from above. The sixth support point 103e of the supply frame 100e is located on a lower left stay 113ec (see FIG. 2(c)) on the opposite side of the supply conveying path 610 (see FIG. 1) from the center of the supply block 110 when viewed from above. Furthermore, the ninth support point 103g of the discharge frame 100g is located on a left stay 113gc (see FIG. 2(a)) on the opposite side of the discharge conveying path 630 from the center of the discharge block 130.

[0042] As described above, the third support point 103f of the imaging frame 100f is supported by the upper left stay 113ef of the supply frame 100e, and the ninth support point 103g of the discharge frame 100g is supported by the upper left stay 113ff of the imaging frame 100f. Therefore, the supported surface (seat surface) is more likely to bend than the two support points (101, 102) located on a support pillar or reinforcing material. In particular, the lowermost supply frame 100e is subject to the weights of both the imaging block 120 and the discharge block 130, which increases the risk of the upper left stay 113ef bending. If the upper left stay 113ef bends, it becomes difficult to resolve the above-mentioned issues.

[0043] 4, a connecting strut 104 is provided to connect an upper-left stay 113ef (as a second stay) and a lower-left stay 113ec (as a first stay) that are provided on the supply frame 100e and extend from the rear side plate 115e in a direction intersecting the vertical direction. When viewed from above, the third support point 103f of the imaging frame 100f is positioned so as to overlap with the connecting strut 104. When viewed from above, the support point 103e of the supply frame 100e is also positioned so as to overlap with the connecting strut 104. In this way, the connecting strut 104 is disposed so as to overlap with the support point 103e of the supply frame 100e and the third support point 103f of the imaging frame 100f. In this way, strength and rigidity are ensured by the connecting support 104, and by positioning the third support point 103f of the imaging frame body 100f on the connecting support 104, the upper left stay 113ef does not bend even when the load of both the imaging block 120 and the discharge block 130 is applied.

[0044] As shown in FIG. 4, the third support point 103f of the imaging frame 100f and the sixth support point 103e of the supply frame 100e may have two or more contact points (1031f and 1032f, 1031e and 1032e) in addition to a single contact point that contacts the supported surface (such as a protrusion on the support point). For example, a single support point can be achieved by narrowly arranging two contact points. However, if a configuration with three support points has two contact points on any one support point, and the contact points are widely spaced, the configuration will ultimately be equivalent to a four-point support. For this reason, in this case, the distance between the two contact points should be "20% or less" of the length of the lower-left stay (113fc, 113ec) on which the support point is provided. For example, if the length of one side of the lower left stay (113fc, 113ec) is "600 mm," the distance between the two abutting portions is "120 mm or less." In this case, the two abutting portions (1031f and 1032f, 1031e and 1032e) are each disposed at a position where they overlap with the connecting support column 104. It is preferable that the two abutting portions are disposed side by side in the front-to-rear direction. There is no particular lower limit to the distance between the two abutting portions, but it is preferable that the distance be "5% or more" of the length of the lower left stay (113fc, 113ec) on which the support portion is provided.

[0045] Furthermore, the mutual positional relationship of the above-mentioned three support points (101, 102, 103) will be explained using Figures 5(a) to 5(c). Figure 5(a) is a schematic diagram showing the positional relationship of support points (101g, 102g, 103g) in the discharge block 130 when viewed from above. Figure 5(b) is a schematic diagram showing the positional relationship of support points (101f, 102f, 103f) in the image creation block 120 when viewed from above. Figure 5(c) is a schematic diagram showing the positional relationship of support points (101e, 102e, 103e) in the supply block 110 when viewed from above.

[0046] To improve usability during maintenance and replacement, the image forming apparatus 1 is configured so that a user can insert and remove components, such as photosensitive drums 11Y-11K and developing units 14Y-14K, from the front of the apparatus main body 1A. A power supply unit for supplying power and drive units such as motors are disposed on the rear side (back side) of the apparatus main body 1A. Furthermore, a document reading unit 30 is disposed on top of the apparatus main body 1A (see FIG. 1), and as described above, the document transport section of the document reading unit 30 can be opened and closed to the front side (front side). In such a vertical transport type image forming apparatus 1, if the apparatus main body 1A is configured as a division into the above-mentioned blocks (110, 120, 130), the centers of gravity of the discharge block 130 and the imaging block 120, which are disposed on the upper side, are located toward the rear.

[0047] When the above three-point support is adopted, if the center of gravity (110g, 110f, 110e; see Figures 5(a), (b), and (c)) of each block (110, 120, and 130) is outside the triangular area formed by the three support points (101, 102, and 103), the three-point support by the three support points (101, 102, and 103) will not be maintained for the block whose center of gravity is outside the triangular area. If this happens, the device main body 1A, which is made up of stacked blocks, will be installed in a deformed state, making it difficult to ensure the flatness of the intermediate transfer belt 21 and the alignment of the pair of rollers. Therefore, in each block (110, 120, 130), the position of the remaining support point (103) must be determined based on the two support points (101, 102) located on the conveying path 60 side so that the center of gravity (110g, 110f, 110e) does not fall outside the triangular area.

[0048] 5(a), in the discharge block 130, the support point 103g is disposed on the left stay 113gc so that the center of gravity 110g including the document reading unit 30 is located on the center line of the triangular area indicated by the dotted line. As described above, the seventh support point 101g of the discharge frame body 100g is disposed on the right front support pillar 114ga, and the eighth support point 102g of the discharge frame body 100g is disposed on the reinforcing member 1150 on the right side of the rear side plate 115g.

[0049] 5B, in the imaging block 120, the support point 103f is disposed on the lower-left stay 113fc so that the center of gravity 110g of the discharge block 130 including the document reading unit 30, the center of gravity 110f of the imaging block 120 alone, and the first combined center of gravity 111 formed by combining the centers of gravity 110g and 110f are located inside a triangular region. The first combined center of gravity 111 is located on a line connecting the center of gravity 110g of the discharge block 130 and the center of gravity 110f of the imaging block 120 alone. As described above, the first support point 101f of the imaging frame 100f is disposed on the right front support pillar 114fa, and the second support point 102f of the imaging frame 100f is disposed on the right reinforcing member 1151 of the rear side panel 115f.

[0050] As shown in FIG. 5(c), in the supply frame 100e, the support point 103e is disposed on the left lower stay 113ec so that the center of gravity 110e of the supply block 110 alone, the first combined center of gravity 111, and the second combined center of gravity 112 formed by combining the center of gravity 110e and the combined center of gravity 111 are located inside a triangular region. The second combined center of gravity 112 is located on a line connecting the center of gravity 110e of the supply block 110 alone and the combined center of gravity 111, and is the center of gravity of the entire apparatus main body 1A. As described above, the fourth support point 101e of the supply frame 100e is disposed on the right front support column 114ea, and the fifth support point 102e of the supply frame 100e is disposed on the right reinforcement member 1152 of the rear side panel 115e.

[0051] In this embodiment, the document reading unit 30, whose center of gravity is biased toward the rear, is disposed on the discharge block 130. Therefore, in the discharge frame 100g on which the weight of the document reading unit 30 is applied, the support point 103g is disposed rearward of the support point 103f of the imaging frame 100f and the support point 103e of the supply frame 100e. In contrast, the support point 103f of the imaging frame 100f is disposed forward of the support point 103g of the discharge frame 100g in the front-to-rear direction. Furthermore, the support point 103e of the supply frame 100e is disposed forward of the support point 103f of the imaging frame 100f in the front-to-rear direction. This is because the center of gravity of the discharge block 130 on which the document reading unit 30 is disposed is shifted rearward, and by positioning the center of gravity of the supply frame 100e forward, the apparatus main body 1A, which is composed of the discharge block 130, the imaging block 120, and the supply block 110, is stabilized.

[0052] As described above, the image forming apparatus 1 of this embodiment includes three separable structures: the supply block 110, the imaging block 120, and the discharge block 130. The supply block 110, the imaging block 120, and the discharge block 130 each include a supply frame 100e, an imaging frame 100f, and a discharge frame 100g, respectively, with various units and components assembled within each frame. The device main body 1A of the image forming apparatus 1 is assembled by stacking the supply block 110, the imaging block 120, and the discharge block 130. The imaging block 120 is supported by the supply block 110 at three points. The discharge block 130 is also supported by the imaging block 120 at three points. Supporting each block at three points in this way reduces the impact of unevenness on the device main body 1A due to the unevenness of the installation surface. This ensures the flatness of the intermediate transfer belt 21 within the device main body 1A and reduces alignment errors between a pair of rollers that transport the recording material S.

[0053] In order to expand the functionality of the image forming apparatus 1, a unit (such as a second fuser) that realizes a new function may be added and assembled to the supply frame 100e, the imaging frame 100f, and the discharge frame 100g. In such a case, the locations of the three support points (101, 102, 103) described above are changed to match the centers of gravity of the supply block 110, the imaging block 120, and the discharge block 130. For example, three support parts that form the three support points may be detachably provided at multiple positions on a support pillar or stay, and the position of each support part in each block may be changed to match the position of the center of gravity of the block to which the new unit has been added.

[0054] <Other embodiments> In the above-described embodiment, the image forming apparatus 1 is described as an intermediate transfer type in which the toner image of each color is primarily transferred from the photosensitive drums 11Y to 11K of each color to the intermediate transfer belt 21, and then the toner image of each color is secondarily transferred to the recording material S. However, the present invention is not limited to this. For example, the image forming apparatus may be a direct transfer type in which the toner image on the photosensitive drum is directly transferred to the sheet by applying a voltage to a transfer roller disposed opposite the photosensitive drum and the conveying belt, with a nip formed between the photosensitive drum and the recording material S conveyed by the conveying belt. [Explanation of symbols]

[0055] 1...image forming apparatus, 11Y, 11M, 11C, 11K...photosensitive member (photosensitive drum), 12Y, 12M, 12C, 12K...charging unit (charger), 13Y, 13M, 13C, 13K...exposure unit (exposure unit), 14Y, 14M, 14C, 14K...developing unit (developer), 21...transfer member (first transfer member, intermediate transfer member, intermediate transfer belt), 31, 32...accommodating body (cassette), 42...conveying rotating body (pair of registration rollers), 44...second transfer member (secondary transfer member, outer secondary transfer roller), 100e...third frame (supply frame), 100f...first frame (imaging frame), 100g...second frame (discharge frame), 101e...fourth support point, 101f...first support point, 101g...seventh support point, 10 2e...fifth support point, 102f...second support point, 102g...eighth support point, 103e...sixth support point, 103f...third support point, 103g...ninth support point, 104...connecting support pillar, 110...third block (supply block), 113ef...second stay (upper left stay), 113ec...first stay (lower left stay), 114eb...support pillar (front left support pillar), 115e...side plate (rear side plate), 120...first block (imaging block), 130...second block (discharge block), 300...supply section (supply unit), 610...third conveying path (supply conveying path), 620...first conveying path (imaging conveying path), 630...second conveying path (discharge conveying path), 700...discharge section (discharge unit), S...recording material

Claims

1. An image forming apparatus for forming an image on a recording material, a first block including a first frame, a transfer member for transferring a toner image onto a recording material, and a first transport path along which the recording material is transported; a second block including a second frame disposed above the first frame so as to be separable from the first frame, a second transport path along which the recording material is transported from the first transport path, and a discharge section that discharges the recording material transported on the second transport path to the outside, The first block is supported at three points, The second block is supported at three points relative to the first block. An image forming apparatus characterized by:

2. a third block including a third frame disposed below the first frame so as to be separable from the first frame, a container for accommodating a recording material, a supply unit for supplying the recording material from the container toward the inside of the first frame, and a third transport path along which the recording material is transported from the container toward the first transport path, The first block is supported at three points relative to the third block.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the first block is supported at three points including a first support point, a second support point, and a third support point; Among the first support point, the second support point, and the third support point, the first support point and the second support point are located closer to the first transport path than a center of the first block when the first block is viewed from above.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. the third support point is located on the opposite side of the first transport path from the center of the first block when the first block is viewed from above; 4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

5. the third block is supported on the installation surface at three points, i.e., a fourth support point, a fifth support point, and a sixth support point; Among the fourth support point, the fifth support point, and the sixth support point, the fourth support point and the fifth support point are located closer to the third transport path than a center of the third block when the third block is viewed from above.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

6. the sixth support point is located on the opposite side of the third transport path from the center of the third block when the third block is viewed from above; 6. The image forming apparatus according to claim 5,

7. the first block is supported at three points including a first support point, a second support point, and a third support point; among the first support point, the second support point, and the third support point, the first support point and the second support point are located closer to the first transport path than a center of the first block when the first block is viewed from above, the third block is supported on the installation surface at three points, i.e., a fourth support point, a fifth support point, and a sixth support point; among the fourth support point, the fifth support point, and the sixth support point, the fourth support point and the fifth support point are located closer to the third transport path than a center of the third block when the third block is viewed from above, the third frame body includes a side plate, a support pillar extending in the vertical direction, a first stay extending from the side plate in a direction intersecting the vertical direction and connecting the side plate and the support pillar, a second stay provided in line above the first stay and connecting the side plate and the support pillar, and a connecting support pillar extending from the first stay toward the second stay and connecting the first stay and the second stay, When the image forming apparatus is viewed from above, the third support point and the sixth support point overlap with the connecting support pillar.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

8. the second block is supported on the first frame body at three points, i.e., a seventh support point, an eighth support point, and a ninth support point; Among the seventh support point, the eighth support point, and the ninth support point, the seventh support point and the eighth support point are located closer to the second transport path than the center of the second block when the second block is viewed from above.

4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

9. the ninth support point is located on the opposite side of the second transport path from the center of the second block when the second block is viewed from above; 9. The image forming apparatus according to claim 8,

10. When the image forming apparatus is viewed from above, the first support point and the seventh support point overlap each other, the second support point and the eighth support point overlap each other when the image forming apparatus is viewed from above; 9. The image forming apparatus according to claim 8,

11. the first support point, the second support point, and the third support point are arranged on the first block so that, when the image forming apparatus is viewed from above, a center of gravity of the first block, a center of gravity of the second block, and a first combined center of gravity obtained by combining the centers of gravity of the first block and the second block are located inside an area connecting the first support point, the second support point, and the third support point; 9. The image forming apparatus according to claim 8,

12. the fourth support point, the fifth support point, and the sixth support point are arranged on the third block so that, when the image forming apparatus is viewed from above, a center of gravity of the third block, a first composite center of gravity obtained by combining the center of gravity of the first block and the center of gravity of the second block, and a second composite center of gravity obtained by combining the center of gravity of the third block and the first composite center of gravity are located inside an area connecting the fourth support point, the fifth support point, and the sixth support point; 8. The image forming apparatus according to claim 7,

13. the transfer member is a first transfer member; A photoreceptor; a charging unit that charges the photosensitive member; an exposure unit that exposes the charged photoreceptor to light to form an electrostatic latent image; a developing unit that develops the electrostatic latent image on the photosensitive member into a toner image; a second transfer member that forms a transfer portion between the first transfer member and the second transfer member, and that transfers a toner image from the first transfer member to a recording material; the first transfer member is an intermediate transfer member onto which a toner image formed on the photosensitive member is primarily transferred; the second transfer member is a secondary transfer member that secondarily transfers a toner image from the intermediate transfer body to a recording material; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images