JP7369548B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus , and more particularly, to an image forming apparatus including a plurality of resin frames divided in a paper conveyance direction.

In recent years, due to demands for weight reduction and cost reduction for image forming apparatuses, resin frames are being used instead of the conventional metal frames to support the components of image forming apparatuses. be.

However, if the entire frame of an image forming apparatus is integrally made of resin, there is a problem in that the mold required for molding becomes larger, leading to an increase in mold construction time and mold manufacturing cost.

In order to solve such problems, the image forming apparatus of the background art disclosed in Patent Document 1 includes a resin frame divided in the paper conveyance direction.

Japanese Patent Application Publication No. 2011-237579

However, in a configuration in which the resin frame is divided in the paper conveyance direction like the image forming apparatus of the background art, there is a problem that it becomes difficult to obtain positional accuracy between each resin frame. There is room for improvement from the perspective of ensuring the positional accuracy of the component parts of the device.

Therefore, the main object of the present invention is to provide a novel image forming apparatus .

Another object of the present invention is to provide an image forming apparatus that can ensure positional accuracy between component parts of an image forming apparatus that includes a plurality of resin frames that are divided in the paper conveyance direction. The goal is to provide

A first aspect of the present invention provides an image forming apparatus that includes a frame that supports a paper transport section that includes a registration roller that adjusts the timing of paper transport, and an image forming section that forms an image on the paper that is transported by the paper transport section. The frame body includes a resin transport frame that supports a paper transport section, a resin process frame that is attached to the downstream side of the transport frame in the paper transport direction and supports an image forming section, and a transport frame and process frame. The image forming apparatus includes a first positioning section provided at a position to engage the frame and coaxial with a drive shaft of the registration roller.

A second invention is dependent on the first invention, and the first positioning part is provided in the transport frame and includes a first engagement part formed around the drive shaft of the registration roller, and a first positioning part provided in the process frame. and a second engaging portion that engages with the first engaging portion.

A third invention is dependent on the second invention, wherein the conveyance frame includes a bearing portion that supports the drive shaft of the registration roller, and the first engaging portion has an arcuate first portion formed coaxially with the bearing portion. The second engaging portion has a second engaging surface that engages with the first engaging surface.

A fourth invention is dependent on any one of the first to third inventions , and is a fixing device that is provided on the downstream side of the image forming section in the paper transport direction and heats and fixes the image formed on the paper. , a discharge section that is installed downstream of the fixing section in the paper transport direction and for discharging the paper out of the device , and a discharge section that is installed on the downstream side of the transport frame in the paper transport direction and supports the fixing section and the discharge section. The fixing frame made of resin is further provided with a second positioning section that positions the fixing frame with respect to the transport frame.

A fifth invention is dependent on the fourth invention, in which the transport frame, the process frame, and the fixing frame are each formed of different types of resin materials.

A sixth invention is dependent on the fourth or fifth invention, wherein the second positioning section is a metal connection fixed to each of the transport frame and the fixing frame, and for positioning the fixing frame with respect to the transport frame. It further includes a member.

A seventh invention is dependent on the sixth invention, and the second positioning section includes a second protrusion provided on the transport frame and a third protrusion provided on the fixing frame at a position a predetermined distance away from the second protrusion. a second fitting part provided on the connecting member and fitting into the second protruding part; and a third fitting part provided on the connecting member and fitting into the third protruding part.

An eighth invention is dependent on the sixth or seventh invention, and the image forming apparatus further includes a first drive mechanism that applies a rotational driving force to the paper conveying section and the image forming section, and the connecting member includes: The coupling members are arranged on both sides of the paper conveyance path along which the paper is conveyed, and one of the connecting members supports the first drive mechanism.

A ninth invention is dependent on the eighth invention, and further includes a second drive mechanism that transmits rotational driving force to the fixing section and the discharge section, and the second drive mechanism is supported by one of the connecting members. Ru.

A tenth invention is dependent on the eighth or ninth invention, and further includes a fastening part for fastening one of the connecting members and the transport frame using a predetermined fixture.

An eleventh invention is dependent on any one of the fourth to tenth inventions, wherein the process frame includes a guide portion that guides the fixing frame to a predetermined position before the fixing frame is fixed to the conveyance frame. include.

A twelfth invention is dependent on any one of the first to eleventh inventions, and a paper guide portion for guiding the paper is formed in the conveyance frame.

According to this invention, in an image forming apparatus including a plurality of resin frames divided in the paper conveyance direction, positional accuracy between the components of the image forming apparatus can be ensured.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is an illustrative view schematically showing the internal structure of an image forming apparatus according to a first embodiment of the present invention when viewed from the front side. FIG. 2 is an illustrative diagram schematically showing the structure of a casing included in the image forming apparatus of FIG. 1. As shown in FIG. FIG. 3 is an illustrative view schematically showing the structure when the casing of FIG. 2 is disassembled. FIG. 4 is a schematic perspective view showing a resin frame and a connecting member attached to the resin frame. FIG. 5 is a schematic perspective view showing the structure of the transport frame. FIG. 6 is a schematic perspective view showing the support structure of the registration rollers. FIG. 7 is a schematic perspective view showing a structure for attaching the process frame to the transport frame. FIG. 8 is a schematic perspective view showing the positioning structure of the process unit. FIG. 9 is a schematic perspective view showing the guide structure of the fixing frame to the process frame. FIG. 10 is a schematic perspective view showing a structure for attaching the fixing frame and drive unit to the transport frame. FIG. 11 is a schematic perspective view showing a structure for attaching the fixing unit to the fixing frame. FIG. 12 is a schematic perspective view showing the structure of the drive unit when viewed from one side. FIG. 13 is a schematic perspective view showing the structure of the drive unit when viewed from the other side. FIG. 14 is a schematic perspective view showing the structure of the drive unit when it is partially disassembled. FIG. 15 is a schematic perspective view showing a structure for attaching the positioning frame to the transport frame. FIG. 16 is a schematic perspective view showing a structure for attaching the positioning frame and the first support frame to the transport frame. FIG. 17 is an illustrative view showing the structure of a resin frame in a modified example. FIG. 18 is a schematic perspective view showing a positioning structure of a positioning frame on a transport frame in a modified example. FIG. 19 is a schematic perspective view showing the positioning structure of the process unit in the second embodiment. FIG. 20 is a schematic perspective view showing a structure for attaching a transport drive frame to a transport frame in a modified example. FIG. 21 is a schematic perspective view showing the attachment structure of the positioning frame to the transport frame and transport drive frame in the embodiment shown in FIG. FIG. 22 is an illustrative view showing the structure of a monochrome resin frame in the third embodiment. FIG. 23 is an illustrative view showing the structure of a resin frame for a collar in the third embodiment. FIG. 24 is a schematic perspective view showing a resin frame for a collar and a connecting member attached to the resin frame. FIG. 25 is a schematic perspective view showing the structure of the color drive unit when viewed from one side. FIG. 26 is a schematic perspective view showing the structure of the color drive unit when viewed from the other side. FIG. 27 is a schematic perspective view showing the structure of the collar drive unit when it is partially disassembled. FIG. 28 is a schematic perspective view showing a gear attachment structure according to specifications to the first support frame. FIG. 29 is a schematic cross-sectional view showing the positioning structure of the process unit in the third embodiment. FIG. 30 is a schematic perspective view showing the mounting structure of the intermediate transfer belt unit.

[First example]
FIG. 1 is an illustrative view schematically showing the internal structure of an image forming apparatus according to a first embodiment of the present invention when viewed from the front side. Referring to FIG. 1, an image forming apparatus 10 according to a first embodiment is a multifunction device having a copy function, a printer function, a scanner function, a facsimile function, etc. (monochrome image). Note that paper, a sheet for an overhead projector, or the like can be used as the recording medium, but below, a case where paper is used will be described.

However, in this specification, in the horizontal direction when the image forming apparatus 10 is viewed from the front, the left side is defined as the left direction, and the right side is defined as the right direction. Also, in the depth direction when the image forming apparatus 10 is viewed from the front, the front side (front side) of the image forming apparatus 10 is defined as the front direction (front direction), and the back side (rear side) of the image forming apparatus 10 is defined as the front side (front side). ) is specified in the rear direction (back direction).

First, the configuration of the image forming apparatus 10 will be schematically described. As shown in FIG. 1, the image forming apparatus 10 includes a housing 12 and an image reading device 14 disposed above the housing 12.

The image reading device 14 includes a document mounting table 16 made of a transparent material. A document holding cover 18 is attached above the document table 16 via a hinge or the like so as to be openable and closable. A document supply tray 20 is provided on the upper surface of the document holding cover 18, and an automatic document feeder (ADF) is provided inside the tray. The ADF automatically supplies originals placed on the original supply tray 20 one by one to the image reading position 22 and discharges them onto the original output tray 24.

Further, the image reading unit 26 built into the image reading device 14 includes a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the surface of the document to light using a light source, and guides the light reflected from the surface of the document to an imaging lens using a plurality of mirrors. Then, the reflected light is imaged by the imaging lens on the light receiving element of the line sensor. The line sensor detects the brightness and chromaticity of the reflected light focused on the light receiving element, and generates image data based on the image of the surface of the document. As the line sensor, a CCD (Charge Coupled Device) or a CIS (Contact Image Sensor) is used.

An operation panel (not shown) is provided on the front side of the image reading device 14 to receive input operations such as print instructions from the user. The operation panel includes a display with a touch panel, a plurality of operation buttons, and the like.

The housing 12 is provided with a control unit (not shown) including a CPU, memory, and the like. The control unit transmits control signals to various parts of the image forming apparatus 10 in response to input operations on the operation panel, etc., and causes the image forming apparatus 10 to perform various operations.

Further, the housing 12 houses (accommodates) various components included in the image forming apparatus 10, such as the image forming section 30, the fixing unit 46, and the drive unit 500 (see FIG. 4, etc.).

The image forming section 30 includes an exposure unit (optical scanning unit) 32, a developing unit 34, a photosensitive drum 36, a cleaner unit (cleaning unit) 38, a charging unit 40, a transfer roller 42, a toner replenishing device 44, etc. An image is formed on the paper conveyed from the tray 48 or the like, and the paper on which the image has been formed is discharged to the discharge tray 50. As image data for forming an image on paper, image data read by the image reading section 26 or image data transmitted from an external computer is used.

The photosensitive drum 36 is an image carrier having a photosensitive layer formed on the surface of a conductive cylindrical base. The charging unit 40 charges the surface of the photoreceptor drum 36 to a predetermined potential. The exposure unit 32 is configured as a laser scanning unit (LSU) equipped with a laser emitting section, a reflecting mirror, etc., and forms an electrostatic latent image according to image data by exposing the surface of the charged photoreceptor drum 36 to light. It is formed on the surface of the photoreceptor drum 36. The developing unit 34 includes a developing tank that stores toner and a developing roller that functions as a developer carrier, and supplies the toner to the surface of the photoreceptor drum 36 to remove the electrostatic latent image formed on the surface of the photoreceptor drum 36. is visualized using toner (forming a toner image). Note that a toner concentration detection sensor for detecting toner concentration is provided inside the developer tank. When the toner concentration detected by the toner concentration detection sensor becomes lower than a predetermined value, toner is replenished from the toner replenishment device 44 to the developer tank. The cleaner unit 38 includes a cleaning blade and a conveyance screw that come into contact with the surface of the photoreceptor drum 36, and removes toner remaining on the surface of the photoreceptor drum 36 after development and image transfer.

However, in the image forming apparatus 10 of the first embodiment, the developing unit 34, the photosensitive drum 36, the charging unit 40, and the cleaner unit 38 are further unitized, and can be attached to and detached from the housing 12 as a process unit 68 including these units. established in

The transfer roller 42 is a member for transferring the toner image formed on the surface of the photoreceptor drum 36 onto a sheet of paper. The transfer roller 42 is arranged to face the photoreceptor drum 36 and is provided to press the photoreceptor drum 36. During image formation, a predetermined voltage is applied to the transfer roller 42, thereby forming a transfer electric field between the photosensitive drum 36 and the transfer roller 42. Due to the action of this transfer electric field, the toner image formed on the outer peripheral surface of the photoreceptor drum 36 is Transferred to paper.

The fixing unit 46 includes a heat roller 62 and a pressure roller 64, and is arranged downstream of the transfer nip section (image forming section 30) in the paper conveyance direction. The heat roller 62 is set to a predetermined fixing temperature (for example, 160° C.), and when the paper passes through the nip area (fixing nip portion) between the heat roller 62 and the pressure roller 64, The toner image transferred to the paper is melted, mixed, and pressed, and the toner image is thermally fixed to the paper.

In addition, a first paper transport path L1 is formed in the housing 12 to send the paper placed on the paper feed tray 48 to the ejection tray 50 via the transfer nip section and the fixing nip section. Ru. In addition, in the housing 12, when double-sided printing is performed on a sheet of paper, a first holder is provided for storing the sheet of paper after single-sided printing has been completed and passed through the fixing nip section on the upstream side of the transfer nip section in the paper conveyance direction. A second paper transport path L2 for returning the paper to the paper transport path L1 is formed.

The first paper transport path L1 is provided with a paper feed roller 52, a pre-transfer transport roller 54, a registration roller 56, a post-fixing transport roller 58, and a discharge roller 60. A plurality of double-sided transport rollers 66 are appropriately provided on the path L2 to provide supplementary propulsion to the paper. However, in the first paper transport path L1 of this embodiment, the paper is transported from the bottom to the top. Hereinafter, the term "paper transport direction" simply means the paper transport direction (direction from the bottom to the top) in the first paper transport path L1.

The paper feed roller 52 includes a pickup roller and a separation roller, and guides the sheets placed on the paper feed tray 48 one by one to the first paper transport path L1.

The pre-transfer conveyance roller 54 and the post-fixation conveyance roller 58 provide a driving force to the paper. The pre-transfer conveyance roller 54 is disposed on the upstream side of the transfer nip portion and the registration roller 56 in the paper conveyance direction, and on the downstream side of the paper feed roller 52 in the paper conveyance direction. The post-fixing conveyance roller 58 is disposed on the downstream side of the fixing nip portion in the paper conveyance direction, and is disposed on the upstream side of the discharge roller 60 in the paper conveyance direction.

The registration rollers 56 are arranged upstream of the transfer nip in the paper conveyance direction, apply a driving force to the paper, and adjust the timing of conveyance of the paper to the transfer nip.

The ejection roller 60 is disposed downstream of the fixing nip portion and the post-fixing transport roller 58 in the paper transport direction, and ejects the paper onto the ejection tray 50 . That is, the discharge roller 60 functions as a discharge section for discharging the paper conveyed through the first paper conveyance path L1.

When performing single-sided printing in the housing 12, the sheets placed on the paper feed tray 48 are guided one by one to the first paper transport path L1 by the paper feed rollers 52, and are transported to the registration rollers 56. Then, the registration roller 56 transports the paper to the transfer nip portion at a timing when the leading edge of the paper and the leading edge of the image information (toner image) on the photoreceptor drum 36 are aligned, and the toner image is transferred onto the paper. Thereafter, the unfixed toner on the paper is thermally fixed as the paper passes through the fixing nip. After the thermal fixation, the paper is transported along the first paper transport path L1 by the post-fixing transport roller 58 and the ejection roller 60, and is ejected to the ejection tray 50.

On the other hand, when performing double-sided printing, when the trailing edge of the paper that has passed through the fixing nip reaches the ejection roller 60 after single-sided printing has been completed, the ejection roller 60 is rotated in the opposite direction so that the paper is reversely rotated. The paper is then guided to the second paper transport path L2. The paper guided to the second paper transport path L2 is transported through the second paper transport path L2 by the duplex transport roller 66, and then guided to the first paper transport path L1 on the upstream side of the registration roller 56 in the paper transport direction. . At this point, the front and back sides of the paper are reversed, so that printing is then performed on the back side of the paper by passing through the transfer nip section and the fixing nip section.

Further, although not shown, the image forming apparatus 10 is provided with a manual paper feed tray. The manual paper feed tray is arranged upstream of the pre-transfer transport roller 54 in the paper transport direction, and instead of the paper feed tray 48, paper is fed from the manual paper feed tray to the first paper transport path L1. There is.

Furthermore, an external paper feeding unit may be attached to the image forming apparatus 10 as described above. In such a case, instead of using the paper feed tray 48 or the manual paper feed tray, the paper may be fed from an external paper feed unit to the first paper transport path L1.

Next, a schematic configuration of the casing 12 of the present invention will be described with reference to FIGS. 2 to 4. Note that in FIGS. 2 to 4, illustration of the image reading device 14 is omitted.

As shown in FIGS. 2 to 4, the housing 12 is configured by a combination of a resin frame 90 and a metal frame 92. That is, a part of the casing 12 is made up of the resin frame 90, and another part of the casing 12 is made up of the metal frame 92.

As shown in FIGS. 2 and 3, in this embodiment, a portion of the housing 12 that constitutes the first paper transport path L1 and the second paper transport path L2, the image forming section 30, the fixing unit 46, and the drive The portion that supports the unit 500 is constructed of a resin frame 90, and the other portions are constructed of a metal frame 92. Note that detailed illustration of the second paper transport path L2 is omitted in FIGS. 2 and 3.

Therefore, the side of the housing 12 where the first paper transport path L1 and the second paper transport path L2 are provided (the right side in this example) is constituted by the resin frame 90, and the opposite side (the left side in this example) This is constructed by a metal frame 92.

The metal frame 92 is composed of a plurality of frames. Specifically, the metal frame includes a side plate frame 94, a first connection frame 96, and a second connection frame 98.

The side plate frame 94 is a frame made of a rectangular metal plate, and constitutes a side wall (left side wall) of the housing 12 on the opposite side of the first paper transport path L1 and the second paper transport path L2.

The first connection frame 96 connects the lower end of the resin frame 90 (specifically, the transport frame 100) and the lower end of the side plate frame 94.

The second connection frame 98 connects the upper surface of the resin frame 90 (specifically, the process frame 200) and the upper end of the side plate frame 94. However, the second connecting frame 98 is arranged below the paper outlet provided in the resin frame 90 (more specifically, the fixing frame 300), and the output tray 50 is provided on the upper surface of the second connecting frame 98. provided.

Note that the first connecting frame 96 and the second connecting frame 98 are not required to have as much strength as the side plate frame 94, nor do they require a high degree of dimensional accuracy. A shape with a small dimension in the direction (direction) may also be used.

As shown in FIGS. 2 to 4, the resin frame 90 is divided in the paper conveyance direction. Specifically, the resin frame 90 is divided into three frames: a transport frame 100, a process frame 200, and a fixing frame 300.

The transport frame 100 is disposed at the most upstream side of the resin frame 90 in the paper transport direction (upstream of the process frame 200 and the fixing frame 300 in the paper transport direction). Specifically, the transport frame 100 is disposed at the lower end (lower right end) of the side where the first paper transport path L1 and the second paper transport path L2 are provided, and below the process frame 200 and the fixing frame 300. .

This conveyance frame 100 includes parts upstream of the registration rollers 56 in the paper conveyance direction, that is, a paper feed roller 52, a pre-transfer conveyance roller 54, a registration roller 56, a paper feed roller for a manual paper feed tray, and some parts. It supports the double-sided conveyance roller 66 (hereinafter, these may be collectively referred to simply as a "paper conveyance section"). Note that the paper feed roller 52 itself may be supported by the paper feed tray 48, and the transport frame 100 may support only the drive section of the paper feed roller 52.

The process frame 200 is disposed in the resin frame 90 on the downstream side of the transport frame 100 in the paper transport direction and on the upstream side of the fixing frame 300 in the paper transport direction. That is, the process frame 200 is arranged between the fixing frame 300 and the transport frame 100.

This process frame 200 includes each component of the image forming section 30 (process unit 68) (exposure unit 32, developing unit 34, photosensitive drum 36, cleaner unit 38, charging unit 40, transfer roller 42, toner supply device 44). support.

The fixing frame 300 is disposed at the most downstream side of the resin frame 90 in the paper transport direction (downstream of the transport frame 100 and the process frame 200 in the paper transport direction). Specifically, the fixing frame 300 is arranged to be stacked on the transport frame 100 and the process frame 200.

This fixing frame 300 supports a fixing unit 46, a post-fixing conveyance roller 58, and a discharge roller 60 (hereinafter, these may be collectively referred to simply as a "fixing discharge section").

However, each of the transport frame 100, the process frame 200, and the fixing frame 300 is formed of a different type of resin material.

For example, the fixing frame 300 supports the fixing unit 46 which becomes hot, so it is required to be more heat resistant than the transport frame 100 and the process frame 200. Therefore, the fixing frame 300 is made of a resin material that has better heat resistance than the transport frame 100 and the process frame 200.

Further, since each component of the image forming section 30 affects the quality of the image printed by the image forming section 30, high positional accuracy is required regarding the mounting position. Therefore, the process frame 200 that supports each component of the image forming section 30 is required to have higher dimensional accuracy (higher dimensional stability) than the transport frame 100 and the fixing frame 300. Therefore, the process frame 200 is formed of a resin material with higher dimensional accuracy than the transport frame 100 and the fixing frame 300.

Note that the transport frame 100 has a transport path forming section for forming a part of the first paper transport path L1. The fixing frame 300 forms part of the first paper conveyance path L1 and the second paper conveyance path L2 by the fixing discharge section. The process frame 200 forms a part of the first paper conveyance path L1 by the image forming section 30 supported by the process frame 200.

That is, by combining (assembling) the transport frame 100, the process frame 200, and the fixing frame 300, the transport path forming portions of the respective frames are connected, and the first paper transport path L1 and the second paper transport path L2 are connected. It is formed.

Although a detailed explanation will be omitted, in the event that paper accumulates (paper jam, jam) in the first paper conveyance path L1, a part of the second paper conveyance path L2 is removed in order to remove the accumulated paper. , may be movably arranged in a common space formed by the transport frame 100, the process frame 200, and the fixing frame 300. Furthermore, the transport frame 100 may be provided with a guide section that guides the paper transported from the second paper transport path L2.

Further, as shown in FIG. 4, a connecting member 400 and a drive unit 500 are attached to the resin frame 90. The connecting member 400 and the drive unit 500 are arranged outside the area of the resin frame 90 where the first paper transport path L1 and the second paper transport path L2 are formed (outside in the front-rear direction). Specifically, the connecting member 400 is attached to the front end (front surface) of the resin frame 90, and the drive unit 500 is attached to the rear end (back surface) of the resin frame 90. Note that the specific configurations of the connecting member 400 and the drive unit 500 will be described later.

Next, the mutual attachment structure of the transport frame 100, process frame 200, and fixing frame 300 will be described with reference to FIGS. 4 to 11.

First, as shown in FIG. 5, in the transport frame 100, a part of the first paper transport path L1 is formed between the paper feed roller 52 and the registration roller 56. A paper guide portion 100a having ribs for guiding the paper is provided between the paper guide portion 100a and the transport roller 54.

Further, as shown in FIGS. 5 to 7, the transport frame 100 includes a front side frame positioning section 104, a back side frame positioning section 106, a drive unit positioning section 102, and a first fastening section 108.

The drive unit positioning section 102 is provided for positioning the drive unit 500 and includes two fitting protrusions 1020 and 1022 provided on the back surface of the transport frame 100 and protruding toward the rear. Each of the fitting protrusions 1020 and 1022 is formed in a substantially cylindrical shape and is arranged at a predetermined distance from each other in the front-rear direction. Moreover, the fitting protrusions 1020 and 1022 are arranged at substantially the same height in the vertical direction.

The front side frame positioning section 104 and the back side frame positioning section 106 are provided for positioning the process frame 200.

The front side frame positioning section 104 is provided at the upper end of the front side of the transport frame 100 and includes an engaging section 1040, a bearing support section 1042, and a fastening section 1044. Further, the back side frame positioning section 106 is provided at the upper end of the back side of the transport frame 100 and includes an engaging section 1060, a bearing support section 1062, and an engaging section 1064.

The bearing support portion 1042 and the bearing support portion 1062 are through holes with a substantially circular cross section that are formed coaxially with the drive shaft of the registration roller 56. The bearing support part 1042 supports the front end of the drive shaft of the registration roller 56 via a bearing 56a attached to one end (front end) of the drive shaft of the registration roller 56, and the bearing support part 1062 supports the drive shaft of the registration roller 56. The rear end of the drive shaft of the registration roller 56 is supported via a bearing 56b attached to the other end (rear end) of the drive shaft.

That is, the registration roller 56 is supported by a bearing support part 1042 and a bearing support part 1062 that are formed coaxially with each other. Further, a drive gear 56c of the registration roller 56 is attached to the rear end of the drive shaft of the registration roller 56 (on the back side of the bearing support portion 1062).

The engaging portion 1040 and the engaging portion 1060 are formed with the drive shaft (center axis) of the registration roller 56 as a reference. Specifically, the engaging portion 1040 and the engaging portion 1060 include an upper surface (first engaging surface) on a substantially circular arc formed with the drive shaft of the registration roller 56 as a reference. Further, the upper surfaces of the engaging portions 1040 and 1060 are formed coaxially with the bearing supporting portions 1042 and 1062, and are formed to protrude upward (downstream in the paper conveyance direction).

In this embodiment, the engaging part 1040 is formed in a substantially cylindrical shape extending in the front-rear direction so as to cover the outside of the bearing support part 1042, and the engaging part 1060 is formed in a substantially cylindrical shape extending in the front-rear direction so as to cover the upper side of the bearing support part 1062. It is formed in an arch shape with a substantially semicircular cross section extending to .

As shown in FIG. 7, the fastening section 1044 is provided on the front surface of the transport frame 100, and has a substantially circular shape in which a screw hole is formed into which a screw (fixing tool) for fixing the process frame 200 to the transport frame 100 is fixed. It is a columnar projection (boss). The fastening section 1044 is arranged near the engaging section 1040.

Returning to FIG. 5, the engaging portion 1064 is a hole provided on the back surface of the transport frame 100, through which a fixing screw (fixture, not shown) for fixing the process frame 200 to the transport frame 100 is inserted. A fastening portion 2062 to which this fixing screw is attached is formed in the process frame 200. The first fastening portion 108 is a screw hole provided on the back surface of the transport frame 100 to which a screw (fixing tool) for fixing the drive unit 500 to the transport frame 100 is fixed. The first fastening portion 108 is arranged between the fitting protrusions 1020 and 1022.

Next, as shown in FIGS. 7 and 8, the process frame 200 includes a front frame positioning section 204, a rear frame positioning section 206, a front process positioning section 210, a rear process positioning section 212, and a front guide section. 220 and a back side guide portion 222 .

The front side frame positioning section 204 and the back side frame positioning section 206 are provided for positioning the process frame 200.

The front frame positioning section 204 is provided at the lower end of the front end of the process frame 200 and includes an engaging section 2040 and a fastening section 2042. Further, the back side frame positioning section 206 includes an engaging section 2060 and a fastening section 2062 provided at the lower end of the rear end of the process frame 200.

The engaging portion 2040 on the front side is provided in a position and shape corresponding to the engaging portion 1040 of the transport frame 100. The engagement portion 2060 on the back side is provided in a position and shape corresponding to the engagement portion 1060 of the transport frame 100.

Specifically, the front-side engaging portion 2040 and the back-side engaging portion 2060 engage a lower surface (second engaging surface) on a substantially circular arc formed with reference to the rotation axis of the registration roller 56, specifically, the drive shaft. include. Further, the second engagement surface of the engagement portion 2040 and the second engagement surface of the back side frame positioning portion 206 have a shape corresponding to the upper surface (first engagement surface) of the engagement portion 1040 and the engagement portion 1060. It is formed.

More specifically, the engaging portion 2040 is a through hole having a substantially circular cross section, and the inner diameter of the engaging portion 2040 is set to be slightly larger than the outer diameter of the engaging portion 1040 of the transport frame 100.

Then, the engaging part 2040 (front side frame positioning part 204) of the process frame 200 and the engaging part 1040 (front side frame positioning part 104) of the transport frame 100 are engaged, and the engaging part 2060 ( By engaging the back side frame positioning section 206) with the engaging section 1060 (back side frame positioning section 106) of the transport frame 100, the process frame is aligned with respect to the transport frame 100 based on the drive shaft of the registration roller 56. 200 is positioned.

That is, the front side frame positioning section 104 and the back side frame positioning section 106 function as an engaging section (corresponding to a first engaging section) on the transport frame 100 side, and the front side frame positioning section 204 and the back side frame positioning section 206 functions as an engaging portion (corresponding to a second engaging portion) on the process frame 200 side.

The front side process positioning section 210 and the back side process positioning section 212 are provided for positioning the process unit 68 with respect to the process frame 200.

The front side process positioning section 210 is provided on the front side of the process frame 200 and includes two fitting protrusions 2100 and 2102 that protrude toward the front side. Each of the fitting protrusions 2100 and 2102 is formed in a substantially cylindrical shape and is arranged at a predetermined distance from each other in the front-rear direction.

Further, as shown in FIG. 8, a process side positioning section 680 is provided at the front end of the process unit 68 including the photoreceptor drum 36. Process side positioning section 680 includes two fitting holes 6800, 6802 corresponding to fitting protrusions 2100, 2102, respectively. The fitting protrusion 2100 and the fitting hole 6800 fit together, and the fitting protrusion 2102 and the fitting hole 6802 fit together, so that the front end of the process unit 68 (image forming section 30) with respect to the process frame 200 The position of is determined.

However, one of the fitting holes 6800 and 6802 (the right fitting hole 6800 in this embodiment) is a through hole (reference hole) with a substantially perfect circular cross section corresponding to the fitting protrusion 2100. The other of the fitting holes 6800 and 6802 (the left fitting hole 6802 in this embodiment) is a long hole (slot hole) extending in the left-right direction. Therefore, the fitting hole 6800 serves as a reference, and the fitting hole 6802 functions as a rotation stopper with the fitting hole 6800 as a reference. Note that the combination of the fitting hole 4020 and the fitting hole 4022, the combination of the fitting hole 4060 and the fitting hole 4062, the combination of the fitting hole 7020 and the fitting hole 7022, and the fitting with the fitting hole 5520 will be described later. Also in combination with the hole 5522, one functions as a reference hole and the other functions as a rotation stopper.

The back side process positioning section 212 is a through hole with a substantially circular cross section formed coaxially with the drive shaft 36a of the photoreceptor drum 36, and supports the bearing 36b of the photoreceptor drum 36. The inner diameter of the back side process positioning section 212 is set to be slightly larger than the outer diameter of the bearing 36b of the photoreceptor drum 36. By fitting the bearing 36b of the photosensitive drum 36 into the back side process positioning section 212, the position of the rear end of the process unit 68 (image forming section 30) with respect to the process frame 200 is determined.

As described above, the process unit 68 is positioned by the front side process positioning section 210 and the back side process positioning section 212 of the process frame 200, the process side positioning section 680 of the process unit 68, and the bearing 36b of the photoreceptor drum 36. .

Returning to FIG. 7, the front side guide section 220 and the back side guide section 222 are used to guide the fixing frame 300 to a predetermined position on the process frame 200 before the fixing frame 300 is positioned and fixed to the transport frame 100. established in

The front guide portion 220 is an inclined surface provided on the upper surface of the front end portion of the process frame 200, and is inclined downward as it goes to the right. The back side guide portion 222 is a groove provided on the upper surface of the rear end portion of the process frame 200 and has a substantially U-shaped cross section.

Next, as shown in FIGS. 9 to 11, the fixing frame 300 includes a front guide section 302 and a back guide section 304.

FIG. 9 is a schematic perspective view showing a guide structure for the fixing frame 300 to the process frame 200, and the fixing frame 300 and the process frame 200 are shown separated for explanation. As shown in FIG. 9, the front guide portion 302 is the left edge (left edge) of the front end portion of the fixing frame 300. As shown in FIG. The front guide section 302 is formed at a position corresponding to the front guide section 220 of the process frame 200.

The back side guide portion 304 is a protrusion that is provided on the lower surface of the rear end portion of the fixing frame 300 and projects downward. This back side guide portion 304 is formed in a position and shape corresponding to the back side guide portion 222 of the process frame 200.

In this way, when the fixing frame 300 is placed on the process frame 200, the front guide section 302 on the front side of the fixing frame 300 comes into contact with the front guide section 220, which is an inclined surface. , the fixing frame 300 moves downward while being restricted from moving to the left. Further, the front side guide portion 302 and the lower end portion of the front side guide portion 220 come into contact with each other, and movement of the fixing frame 300 to the left is restricted.

Further, when the fixing frame 300 is placed on the process frame 200, on the back side of the fixing frame 300, the back side guide part 304 moves downward along the back side guide part 222, and the back side guide part 304 moves downward along the back side guide part 222. By fitting the portion 304 and the back guide portion 222, movement of the fixing frame 300 in the left-right direction is restricted. Therefore, the fixing frame 300 is stably supported by the process frame 200 at a predetermined position.

As shown in FIG. 10, the process frame 200 (not shown) is attached to the transport frame 100, and the fixing frame 300 is placed on the process frame 200. It is attached to the transport frame 100 via 500. Note that in FIG. 10, illustration of the process frame 200 is omitted in order to clearly display the detailed structure in which the fixing frame 300 is attached to the transport frame 100.

Specifically, the fixing frame 300 is attached to the transport frame 100 via the connecting member 400 on the front side, and is attached to the transport frame 100 via the drive unit 500 on the back side.

The connecting member 400 is a metal plate having a substantially L-shaped cross section and extending in the vertical direction. This connecting member 400 is provided so as to cover the right front corners of the transport frame 100, the process frame 200, and the fixing frame 300.

Furthermore, the transport frame 100 includes a connecting member positioning section 120 and a fastening section 122, and the fixing frame 300 includes a connecting member positioning section 306 and a fastening section 308. The connecting member positioning section 120, the fastening section 122, the connecting member positioning section 306, and the fastening section 308 are provided for positioning the fixing frame 300.

The connecting member positioning section 120 is provided on the front surface of the transport frame 100 and includes two fitting protrusions 1200 and 1202 that protrude toward the front. Each of the fitting protrusions 1200 and 1202 is formed into a substantially cylindrical shape, and is arranged at a predetermined distance from each other in the vertical direction.

The fastening portion 122 is a screw hole into which a connecting member fixing screw (connecting member fixture) 400b for fixing the connecting member 400 to the transport frame 100 is fixed. The fastening portion 122 is arranged between the fitting protrusions 1200 and 1202 in the vertical direction.

The connecting member positioning section 306 is provided on the front surface of the fixing frame 300 and includes two fitting protrusions 3060 and 3062 that protrude toward the front. Each of the fitting protrusions 3060 and 3062 is formed into a substantially cylindrical shape and is arranged at a predetermined distance from each other in the vertical direction.

The fastening portion 308 is a screw hole into which a connecting member fixing screw 400a for fixing the connecting member 400 to the fixing frame 300 is fixed. Fastening portion 308 is arranged between fitting protrusions 3060 and 3062.

Further, the connecting member 400 is provided with a transport frame positioning section 402, a transport frame fastening hole 404, a fixing frame positioning section 406, and a fixing frame fastening hole 408.

The transport frame positioning section 402 is provided at a position corresponding to the connecting member positioning section 120 of the transport frame 100, and includes two fitting holes 4020, 4022 corresponding to the fitting protrusions 1200, 1202, respectively. The position of the connecting member 400 with respect to the transport frame 100 is determined by fitting the fitting protrusion 1200 and the fitting hole 4020 and fitting the fitting protrusion 1202 and the fitting hole 4022.

Fixing frame positioning section 406 is provided at a position corresponding to connecting member positioning section 306 of fixing frame 300, and includes two fitting holes 4060, 4062 corresponding to fitting protrusions 3060, 3062, respectively. The position of the connecting member 400 with respect to the fixing frame 300 is determined by fitting the fitting protrusion 3060 and the fitting hole 4060 and fitting the fitting protrusion 3062 and the fitting hole 4062.

The transport frame fastening hole 404 is a through hole formed at a position corresponding to the fastening portion 122 of the transport frame 100. The fixing frame fastening hole 408 is a through hole formed at a position corresponding to the fastening portion 308 of the fixing frame 300. In the connecting member 400, a connecting member fixing screw 400b is fixed to the fastening part 122 through the transport frame fastening hole 404, and a connecting member fixing screw 400a is fixed to the fastening part 308 through the fixing frame fastening hole 408. It is attached to the transport frame 100 by.

Further, the drive unit 500 includes a drive frame 600, and the drive frame 600 is provided with a fixing frame positioning hole 612, a fixing frame fastening hole 620, a transport frame engaging portion 702, and a transport frame fastening hole 720.

The fixing frame 300 is provided with a fitting protrusion 312 and a fastening part 314 on the back side. The fixing frame positioning hole 612 provided in the drive frame 600 is a through hole formed at a position corresponding to the fitting protrusion 312 of the fixing frame 300. By fitting the fitting protrusion 312 into the fixing frame positioning hole 612, the fixing frame 300 is positioned with respect to the drive frame 600.

The transport frame engaging portion 702 of the drive frame 600 is provided at a position corresponding to the drive unit positioning portion 102 provided on the back surface of the transport frame 100. The transport frame engaging portion 702 includes two fitting holes 7020 and 7022 corresponding to the fitting protrusions 1020 and 1022 of the transport frame 100, respectively. The position of the drive frame 600 with respect to the transport frame 100 is determined by fitting the fitting protrusions 1020 and 1022 of the transport frame 100 into the fitting holes 7020 and 7022 of the drive frame 600, respectively. That is, the position of the fixing frame 300 with respect to the transport frame 100 is determined by the drive frame 600.

The fixing frame fastening hole 620 of the drive frame 600 is a through hole formed at a position corresponding to the fastening part 314 provided on the back surface of the fixing frame 300. The transport frame fastening hole 720 of the drive frame 600 is a through hole formed at a position corresponding to the first fastening part 108 (see FIG. 5) of the transport frame 100.

The drive frame 600 is fastened to the fixing frame 300 by fixing the drive frame fixing screw 600a to the fastening portion 314 on the back side of the fixing frame 300 through the fixing frame fastening hole 620. Then, the driving frame fixing screw 600a is fixed to the first fastening portion 108 through the transport frame fastening hole 720, thereby attaching it to the transport frame 100.

As described above, the fixing frame 300 is positioned and fixed to the transport frame 100 via the connecting member 400 and the drive frame 600.

Further, as shown in FIG. 11, the fixing frame 300 is provided with a discharge guide section 300a between the fixing nip section and the discharge roller 60 for guiding the paper that has passed through the fixing nip section. Further, the fixing frame 300 is provided with a fixing unit guide section 310 for guiding the fixing unit 46.

Furthermore, a drive gear 62a of the fixing unit 46 is provided at the rear end of the fixing unit 46. This drive gear 62a engages with a drive gear 62b (see FIG. 10) provided in the drive unit 500.

Next, the configuration of the drive unit 500 of the present invention and its mounting structure will be described with reference to FIGS. 10 to 16.

As shown in FIGS. 10 to 14, the drive unit 500 includes a first drive source 502, a transport drive mechanism 510, a first process drive mechanism 512, a fixing drive mechanism 514, and a drive frame 600.

The first drive source 502 is a drive motor for applying rotational driving force to a plurality of rotating bodies included in the image forming apparatus 10 . However, the plurality of rotating bodies refers to various rollers included in the paper transport section (for example, the paper feed roller 52, the pre-transfer transport roller 54, the registration roller 56, the paper feed roller for the manual paper feed tray, and some of the double-sided transport rollers). roller 66), various rotating bodies included in the image forming section 30 (for example, photosensitive drum 36, developing roller, and conveyance screw), and various rollers included in the fixing and discharging section (for example, heat roller 62, post-fixing conveyance roller 58, and discharging roller). 60) etc.

The transport drive mechanism 510 is a mechanism for transmitting the rotational driving force from the first drive source 502 to various rollers included in the paper transport section. The first process drive mechanism 512 is a mechanism for transmitting the rotational drive force from the first drive source 502 to various rotating bodies included in the image forming section 30. The fixing drive mechanism 514 is a mechanism for transmitting the rotational driving force from the first drive source 502 to various rollers included in the fixing discharge section.

However, each of the transport drive mechanism 510, the first process drive mechanism 512, and the fixing drive mechanism 514 is configured to include power transmission elements such as pulleys, belts, gear trains, and couplings as necessary. be done. This also applies to a second process drive mechanism 516 and a third process drive mechanism 518, which will be described later.

Further, each of the transport drive mechanism 510, the first process drive mechanism 512, and the fixing drive mechanism 514 includes a clutch for selectively transmitting rotational driving force to each of the plurality of rotating bodies included in the image forming apparatus 10. Therefore, each of the plurality of rotating bodies is individually driven to rotate or stopped.

Next, the configuration of drive frame 600 will be explained. The drive frame 600 is made of metal, for example, and includes a first support frame 602 arranged on the back side, and a positioning frame 700 detachably attached to the front side of the first support frame 602.

The first support frame 602 supports the first drive source 502 , the transport drive mechanism 510 , the first process drive mechanism 512 , and the fixing drive mechanism 514 . However, the first drive source 502 is attached to the back surface of the first support frame 602, and the transport drive mechanism 510, the first process drive mechanism 512, and the fixing drive mechanism 514 are attached to the front surface of the first support frame 602.

Further, as shown in FIG. 14, the first support frame 602 includes a first positioning fixing part 604, a second positioning fixing part 606, the above-described fixing frame fastening hole 620, and fixing frame positioning hole 612.

The first positioning fixing section 604 and the second positioning fixing section 606 are provided for positioning the first support frame 602 with respect to the positioning frame 700, and are arranged in the left and right direction by the transport drive mechanism 510, the first process drive mechanism 512, and the fixing drive mechanism. 514. Specifically, the first positioning and fixing part 604 is provided at the right end of the first support frame 602 , and the second positioning and fixing part 606 is provided at the left end of the first support frame 602 .

The first positioning fixing part 604 includes a fitting protrusion 6040 that protrudes forward (toward the positioning frame 700 side), and a frame fixing screw (frame fixing screw) for fixing the positioning frame 700 and the first support frame 602 to each other. and two screw holes 6042 and 6044 to which the fixture 700a is fixed. The fitting protrusion 6040 is arranged between the two screw holes 6042, 6044.

The second positioning fixing part 606 includes a fitting protrusion 6060 that projects forward, and a screw hole 6062 provided near the fitting protrusion 6060 and into which a frame fixing screw 700a is fixed.

As shown in FIGS. 13 and 14, the positioning frame 700 is provided to cover the front side of the first process drive mechanism 512. That is, the first process drive mechanism 512 is housed between the first support frame 602 and the positioning frame 700.

Further, as shown in FIGS. 14 to 16, the positioning frame 700 includes a transport frame engaging part 702, a first positioning fixing part 704, and a second positioning fixing part 706.

The transport frame engaging part 702 is provided at a position corresponding to the drive unit positioning part 102 of the transport frame 100, and includes two fitting holes 7020, 7022 corresponding to the fitting protrusions 1020, 1022, respectively. As shown in FIG. 15, the positioning frame 700 is positioned relative to the transport frame 100 by fitting the fitting protrusion 1020 and the fitting hole 7020 and by fitting the fitting protrusion 1022 and the fitting hole 7022. is decided. As described above, the transport frame engaging part 702 is attached to the transport frame 100 by fixing the drive frame fixing screw 600a to the first fastening part 108 through the transport frame fastening hole 720. Note that the fitting hole 7020 has a long hole shape.

Returning to FIG. 14, the first positioning fixing part 704 is provided at a position corresponding to the first positioning fixing part 604 of the first support frame 602, and has a fitting hole 7040 corresponding to the fitting protrusion 6040 and two It includes fastening holes 7042 and 7044 formed at positions corresponding to the screw holes 6042 and 6044.

The second positioning fixing part 706 is provided at a position corresponding to the second positioning fixing part 606 of the first support frame 602, and is provided at a position corresponding to a fitting hole 7060 corresponding to the fitting protrusion 6060 and a screw hole 6062. A fastening hole 7062 is formed.

Then, the fitting protrusion 6040 and the fitting hole 7040 fit together, and the fitting protrusion 6060 and the fitting hole 7060 fit together, thereby determining the position of the first support frame 602 with respect to the positioning frame 700. That is, the first support frame 602 (drive unit 500) is positioned with respect to the transport frame 100 via the positioning frame 700.

Further, the positioning frame 700 and the first support frame 602 are fixed and integrated by frame fixing screws 700a fixed to the screw holes 6042, 6044, 6062 via the fastening holes 7042, 7044, 7062.

Although not shown, when the positioning frame 700 is attached to the first support frame 602 and attached to the resin frame 90 (transport frame 100, process frame 200, and fixing frame 300), the drive mechanisms 510, 512 , 514 and each of the plurality of rotating bodies included in the image forming apparatus 10 are connected, and the rotational driving force of the first drive source 502 can be transmitted to the plurality of rotating bodies. In other words, the series of drive mechanisms supported by the first support frame 602 are positioned and fixed to the conveyance frame 100 with high accuracy, so that the first support frame 602 is positioned and fixed along the paper conveyance path.

As described above, according to the first embodiment, the process frame 200 is positioned based on the drive shaft of the registration roller 56 attached to the transport frame 100. Therefore, the process unit 68 (transfer nip portion) attached to the process frame 200 can be attached with high accuracy to the position of the registration roller 56 attached to the transport frame 100.

That is, in the image forming apparatus 10 provided with a resin frame body (frame) divided in the paper conveyance direction, positional accuracy between the constituent parts of the image forming apparatus 10 can be ensured.

Further, according to the first embodiment, the front side frame positioning section 104, which is provided on the transport frame 100 and includes the first engagement surface on a substantially circular arc formed coaxially with the center axis of the registration roller 56, and the back side frame It includes a positioning section 106, a front frame positioning section 204 and a rear frame positioning section 206, which are provided on the process frame 200 and include a second engagement surface that engages with the first engagement surface. Therefore, the process frame 200 can be appropriately positioned with respect to the transport frame 100, and the positional accuracy between the components of the image forming apparatus 10 can be ensured.

Furthermore, since the fixing frame 300 is positioned and fixed to the transport frame 100 via the connecting member 400 and the drive frame 600, positional accuracy between the components of the image forming apparatus 10 can be ensured. In other words, positional accuracy between the components of the image forming apparatus 10 attached to the fixing frame 300 and the transport frame 100 can be ensured.

To summarize the above, according to the first embodiment, the process frame 200, the fixing frame 300, the connecting member 400, and the drive unit 500 are all positioned with respect to the transport frame 100, so that the various The positional accuracy of the component parts can be ensured. In other words, various components included in the image forming apparatus 10 can be arranged with high precision so as to form a paper transport path with the transport frame 100 as a reference. In other words, even with a configuration in which the resin frame is divided in the paper transport direction, various components included in the image forming apparatus 10 can be accurately arranged along the paper transport path.

According to the first embodiment, the transport frame 100, the process frame 200, and the fixing frame 300 are each made of different types of resin materials, so the optimal material is selected according to the characteristics of each frame. be able to. Therefore, there is no need to use expensive materials for parts other than those that require positional accuracy or heat resistance, and as a result, manufacturing costs can be reduced. Furthermore, by dividing the resin frame, each mold is made smaller, so it goes without saying that the manufacturing cost and period of the mold can be shortened.

Note that, as a structure different from the above-described embodiment, the transport frame 100 and the fixing frame 300 may be in direct contact with each other. The structure of the resin frame 90 in a modified example (the embodiment in FIG. 17) will be described below with reference to FIG. 17.

As shown in FIG. 17, in the embodiment shown in FIG. 17, the right end 200b of the process frame 200 is positioned to the left of the right end of the housing 12 (resin frame 90). In this way, a space extending in the vertical direction is secured on the right side of the process frame 200. Utilizing this space, a protrusion 100b that protrudes upward from the upper end of the transport frame 100 is formed on the transport frame 100, and a protrusion 100b that protrudes downward from the lower end of the fixing frame 300 is formed on the fixing frame 300. 300b is formed.

If the upper surface of the protrusion 100b of the transport frame 100 and the lower surface of the protrusion 300b of the fixing frame 300 are brought into contact with each other, the vertical positions of the transport frame 100 and the fixing frame 300 can be determined. Therefore, in the embodiment shown in FIG. 17, since the connecting member 400 can be omitted, the number of parts can be reduced, and thus the manufacturing cost can be reduced.
[Second example]
The image forming apparatus 10 of the second embodiment is the same as the image forming apparatus 10 of the first embodiment except for the positioning structure of the image forming section 30 (process unit 68), so the content differs from the first embodiment. will be explained, and redundant explanations will be omitted.

In the second embodiment, the rear end (drive unit 500 side) of the process unit 68 is positioned by a positioning frame 700 to which the drive unit 500 is attached. Therefore, the process frame 200 does not include the back side process positioning part 212, and instead of the back side process positioning part 212, a through hole is provided in the process frame 200 to avoid the bearing guide part 7100 of the bearing guide member 710, which will be described later. formed on the back. (not shown)
The structure of the positioning frame 700 and the positioning structure of the process unit 68 by the positioning frame 700 will be described below with reference to FIGS. 18 and 19.

As shown in FIGS. 18 and 19, a bearing guide member 710 is attached to the front surface of the positioning frame 700 to define the mounting position of the process unit 68 on the rear side. The bearing guide member 710 is attached to the front side of an opening 712 provided in the positioning frame 700. The bearing guide member 710 includes a bearing guide part 7100 having a cylindrical guide part on the inside that protrudes forward and engages with the bearing 36b of the process unit 68, and a mounting guide part 7102 that engages with the opening 712 of the positioning frame 700. and has.

In the bearing guide section 7100, the inner diameter of the cylindrical guide section is set to be slightly larger than the outer diameter of the bearing 36b of the photoreceptor drum 36. The mounting guide portion 7102 is a wall-shaped guide that extends from the main body of the bearing guide member 710 toward the positioning frame 700 along the edge of the opening 712 of the positioning frame 700. The mounting position of the bearing guide member 710 relative to the positioning frame 700 is determined by the engagement between the mounting guide portion 7102 and the opening 712, and the bearing guide member 710 is fixed to the positioning frame 700 by a fastening member such as a screw.

Next, a structure for positioning the positioning frame 700 to the transport frame 100 will be described.

As shown in FIG. 18, in the second embodiment, the drive unit positioning part 102 (corresponding to the positioning part of the positioning frame 700 to which the drive unit 500 is attached) included in the transport frame 100 is replaced with the fitting protrusion 1022. , a bearing 1024 attached to the rotation shaft of the registration roller 56, specifically the drive shaft.

Furthermore, in the second embodiment, the transport frame engaging portion 702 of the positioning frame 700 is provided coaxially with the bearing 1024 (the drive shaft of the registration roller 56) instead of the fitting hole 7022 corresponding to the fitting protrusion 1022. A fitting hole 7024 is formed. Therefore, the position of the positioning frame 700 with respect to the transport frame 100 is determined by fitting the fitting protrusion 1020 and the fitting hole 7020 and fitting the fitting hole 7024 and the bearing 1024. In this case, since the fitting hole 7020 is a long hole, the combination of the fitting hole 7024 and the bearing 1024 serves as a reference, and the combination of the fitting protrusion 1020 and the fitting hole 7020 serves as a rotation stopper. That is, the positioning frame 700 is positioned around the rotation axis of the registration roller 56, more specifically, the drive shaft.

Next, with reference to FIG. 19, a positioning structure for the process unit 68 in the second embodiment will be described. As shown in FIG. 19, in the second embodiment, the bearing 36b of the photosensitive drum 36 is fitted into the bearing guide part 7100 of the bearing guide member 710 attached to the positioning frame 700, so that the process unit relative to the process frame 200 is The position of the rear end of 68 is determined. That is, the bearing guide member 710 functions as a member (attachment positioning member) for positioning the process unit 68 (image forming section 30), and the bearing guide section 7100 functions as an attachment positioning section for the process unit 68.

Note that the structure for positioning the front end of the process unit 68 with respect to the process frame 200 is the same as in the first embodiment, so a description thereof will be omitted.

As described above, since the bearing guide member 710 is positioned with high accuracy with respect to the rotation axis (more specifically, the drive shaft) of the registration roller 56 by the positioning frame 700, the photosensitive drum 36 is positioned at a predetermined position with respect to the registration roller 56. It can be placed with high precision in the positional relationship. In other words, even if the resin frame 90 is divided into the transport frame 100 and the process frame 200 in the paper transport direction, the position of the photoreceptor drum 36 with respect to the registration roller 56 can be controlled with high precision, so that the position of the photoreceptor drum 36 can be controlled accurately. Paper can be transported accurately and stably to the transfer position. Note that in FIG. 19, the process frame 200 is not shown in order to make the mounting structure of the process unit 68 easier to understand.

Note that the positioning frame 700 may be made of metal to stably manage the position of the photoreceptor drum 36 with respect to the registration roller 56 by reducing the influence of changes over time and the like.

Further, in the second embodiment, the bearing guide member 710 is made of resin, but it may be formed integrally with the positioning frame 700 made of metal, or the positioning frame 700 is made of resin and integrated with the bearing guide member 710. It may be formed as follows.

Further, since the process unit 68 is positioned on the positioning frame 700, the rear side frame positioning section 206 of the process frame 200 described in the first embodiment may be omitted.

As described above, in the second embodiment, the process unit 68 uses the bearing guide member 710 of the positioning frame 700 positioned on the transport frame 100 instead of the back side process positioning part 212 of the process frame 200. Positioned. The positioning frame 700 is positioned with respect to the transport frame 100 based on the rotation axis, more specifically, the drive shaft, of the registration roller 56 included in the transport frame 100. In other words, the member provided with the positioning section for positioning the process unit 68 is not the large process frame 200 but the smaller positioning frame 700. The smaller the member, the easier it is to achieve dimensional accuracy, so the process unit 68 can be placed with respect to the registration roller 56 with higher accuracy. Further, by making the positioning frame 700 made of metal, the positions of the process unit 68 and the registration rollers 56 can be managed more stably and accurately. (It becomes less susceptible to deformation and strain caused by thermal expansion and changes over time.)
In other words, according to the second embodiment, in an image forming apparatus including a plurality of resin frames divided in the paper conveyance direction, the positional accuracy between the components of the image forming apparatus 10 is improved, especially the process unit with respect to the registration roller 56. The positional accuracy of 68 (transfer nip portion) can be further improved.

In addition, instead of the configuration described in the second embodiment, the transport frame 100 is provided with a transport drive frame 550 equipped with a drive unit such as the transport roller 54, and the positioning frame 700 is connected to the transport frame 550 via the transport drive frame 550. It may be positioned and fixed at 100.

The configuration of the transport drive frame 550 and the mounting structure of the positioning frame 700 to the transport frame 100 in a modified example (the embodiment in FIG. 20) will be described below with reference to FIGS. 20 and 21.

As shown in FIGS. 20 and 21, the conveyance frame 100 includes a metal conveyance drive frame 550 that supports the rotation shafts of the registration rollers 56, the conveyance rollers 54, etc., and driving parts such as gears together with the conveyance frame 100. Further, the conveyance drive frame 550 includes a mechanism for transmitting the rotational driving force from the first drive source 502 to the registration roller 56, the conveyance roller 54, and the like. In other words, a part of the transport drive mechanism 510 is included.

The transport drive frame 550 includes a transport drive positioning part 552, a first fastening hole 554, a second fastening hole 556, and a plurality of third fastening holes 558.

The transport drive positioning section 552 is provided at a position corresponding to the drive unit positioning section 102 of the transport frame 100, and includes two fitting holes 5520, 5522 corresponding to the fitting protrusions 1020, 1022, respectively. The position of the transport drive frame 550 with respect to the transport frame 100 is determined by the fitting protrusion 1020 and the fitting hole 5520 fitting, and the fitting protrusion 1022 and the fitting hole 5522 fitting together.

The first fastening hole 554 is formed at a position corresponding to the first fastening part 108 of the transport frame 100. In the embodiment shown in FIG. 20, a second fastening section 110 that is different from the first fastening section 108 is provided on the back surface of the transport frame 100. The second fastening hole 556 is formed at a position corresponding to the second fastening portion 110.

Furthermore, in the embodiment shown in FIG. 20, the transport frame 100 is provided with a transport drive frame fastening section 130 for fixing the transport drive frame 550 to the transport frame 100. The transport drive frame fastening section 130 is provided on the back surface of the transport frame 100, and includes a plurality of screw holes 130a into which transport drive frame screws (transport drive frame fixtures) 550a are fixed. Each of the plurality of third fastening holes 558 is formed at a position corresponding to each of the plurality of screw holes 130a.

The transport drive frame 550 is attached to the transport frame 100 by a plurality of transport drive frame screws 550a fixed to the plurality of screw holes 130a through a plurality of third fastening holes 558. The strength (rigidity) of the resin transport frame 100 is increased by integrally fastening the metal transport drive frame 550, and the resistance against bending and deformation is improved.

Further, as shown in FIG. 21, in the embodiment shown in FIG. 20, a transport frame fastening hole 722 is formed in the positioning frame 700 in addition to the transport frame fastening hole 720. The transport frame fastening hole 722 is formed at a position corresponding to the second fastening part 110 of the transport frame 100 and the second fastening hole 556 of the transport drive frame 550.

In the drive frame 600 (positioning frame 700), drive frame fixing screws 600a are fixed to the first fastening part 108 through the transport frame fastening hole 720 and the first fastening hole 554, and the drive frame fixing screw 600a is fixed to the first fastening part 108 through the transport frame fastening hole 722 and the second fastening hole. By fixing the drive frame fixing screw 600a to the second fastening portion 110 via the screw 556, the drive frame is attached (more firmly) to the transport frame 100. That is, in the embodiment shown in FIG. 20, the drive frame 600 (positioning frame 700) is attached to the transport frame 100 via the transport drive frame 550.

In addition, in FIG. 21, although the case where the positioning frame 700 and the conveyance drive frame 550 are fastened together to the conveyance frame 100 was given as an example, it does not need to be limited to this. For example, the positioning frame 700 and the transport drive frame 550 may be fixed with screws or the like, and separately, the transport drive frame 550 and the transport frame 100 may be fixed with screws or the like. Even in this case, the positioning frame 700 is attached to the transport frame 100 via the transport drive frame 550. Further, since the positioning frame 700 can be stably attached to the transport frame 100 with high precision by the transport drive frame 550, the fitting hole 7024 that fits into the bearing 1024 of the registration roller 56 may be omitted.

As described above, according to the embodiment in FIG. 20, since the transport drive frame 550 is attached to the transport frame 100, the strength of the transport frame 100 can be increased, and the transport frame 100 can be prevented from bending due to external pressure, changes over time, etc. , it is resistant to warpage, etc., and the posture of the transport frame 100 can be stabilized. Therefore, the positional accuracy of each component supported by the transport frame 100 can be ensured.

In other words, according to the embodiment shown in FIG. 20, the positional accuracy between the components of the image forming apparatus 10 can be further improved in an image forming apparatus including a plurality of resin frames divided in the paper conveyance direction.
[Third example]
The image forming apparatus 10 of the third embodiment is the same as the image forming apparatus 10 of the first embodiment except that it is selectively provided with a resin frame having different specifications and a drive unit having different specifications. Contents that are different from the embodiments will be explained, and duplicate explanations will be omitted.

As shown in FIGS. 22 and 23, the image forming apparatus 10 of the third embodiment selectively includes either a monochrome resin frame 90A or a color resin frame 90B. The monochrome resin frame 90A includes a monochrome process frame 200A that supports the monochrome image forming section 30A, and the color resin frame 90B includes a color process frame that supports the color image forming section 30B. Contains 200B.

However, the configuration of the monochrome resin frame 90A is the same as the configuration of the resin frame 90 described in the first embodiment, and the configuration of the monochrome image forming section 30A is the same as that of the image forming section described in the first embodiment. Since the configuration is the same as that of No. 30, a description thereof will be omitted.

The schematic configuration of the color image forming section 30B will be described below with reference to FIG. 23. As shown in FIG. 23, the color image forming section 30B includes an exposure unit 32, a developing unit 34, a photosensitive drum 36, a cleaner unit 38, a charging unit 40, a toner replenishing device 44, an intermediate transfer belt unit 70, and a transfer roller. (Secondary transfer roller) 80 etc. are provided. Note that in FIG. 23, illustration of the cleaner unit 38, charging unit 40, and toner replenishing device 44 is omitted.

For example, the image data handled by the color image forming section 30B corresponds to a color image of four colors: black (K), cyan (C), magenta (M), and yellow (Y). Therefore, four developing units 34, four photosensitive drums 36, four cleaning units 38, and four charging units 40 are provided so as to form four types of latent images corresponding to each color, thereby forming four image stations. configured. The four image stations are arranged horizontally in a line along the running direction (left-right direction) of the surface of the intermediate transfer belt 72.

The intermediate transfer belt unit 70 includes an intermediate transfer belt 72, a drive roller 74, a driven roller 76, four intermediate transfer rollers 78, and the like. The intermediate transfer belt 72 is disposed above the photoreceptor drums 36 of the four image stations and is provided so as to be in contact with each photoreceptor drum 36. Then, by sequentially overlapping and transferring the toner images of each color formed on each photoreceptor drum 36 onto the intermediate transfer belt 72 using the intermediate transfer roller 78, a multicolor toner image is formed on the intermediate transfer belt 72. be done. Further, a secondary transfer roller 80 is disposed at a position facing the drive roller 74 via the intermediate transfer belt 72, and a nip area (secondary transfer roller 80) between the intermediate transfer belt 72 and the secondary transfer roller 80 As the paper passes through the nip portion), the toner image formed on the intermediate transfer belt 72 is transferred to the paper.

Each component of the color image forming section 30B is supported by a color process frame 200B.

Next, a schematic configuration of the collar resin frame 90B will be described with reference to FIGS. 23 and 24. As shown in FIGS. 23 and 24, the color resin frame 90B includes a transport frame 100, a color process frame 200B, and a fixing frame 300.

Note that the only difference between the monochrome resin frame 90A and the color resin frame 90B is the shape of the process frame 200. Therefore, the color resin frame 90B can use (share) the same transport frame 100 and fixing frame 300 included in the monochrome resin frame 90A.

Further, the monochrome process frame 200A and the color process frame 200B have the same configurations of the front side frame positioning section 204, the back side frame positioning section 206, the front side guide section 220, and the back side guide section 222. .

Therefore, also in the color resin frame 90B, the positioning and mounting structure between the transport frame 100 and the color process frame 200B, the positioning and mounting structure between the process frame 200B and the fixing frame 300, and the positioning and mounting structure between the transport frame 100 and the fixing frame 300 The positioning and mounting structure are the same as in the first embodiment, so their explanation will be omitted. Furthermore, in the color resin frame 90B, the same connecting member 400 for positioning the transport frame 100 and the fixing frame 300 as in the monochrome resin frame 90A can be used.

However, when the color resin frame 90B (color image forming section 30B) is applied, the drive unit 500 is replaced with the monochrome drive unit 500A (same as the drive unit 500 of the first embodiment). Instead, a color drive unit 500B is used. Note that FIG. 24 shows the form of the second embodiment applied to color, so each component of the image forming section 30B is not a process frame 200B for color, but a positioning frame 700B for color. Supported by Further, the collar drive unit 500B is positioned and fixed by a collar positioning frame 700B. The structure for positioning and attaching the collar positioning frame B to the transport frame 100 is the same as that in the second embodiment, so the description thereof will be omitted. Further, the color positioning frame 700B includes a plurality of bearing guide members 752K, 752C, 752M, 752Y in order to support the plurality of process units 68 and the intermediate transfer belt unit 70 (specifically, the driving roller 74 of the intermediate transfer belt). , 750, which is different from the monochrome positioning frame 700A, but the effect obtained only by the difference in the number of bearing guide members is the same as that explained in the second embodiment.

The detailed configuration of the color drive unit 500B will be described below with reference to FIGS. 25 to 28.

As shown in FIGS. 25 to 27, the color drive unit 500B includes a first drive source 502, a second drive source 504, a third drive source 506, a transport drive mechanism 510, a fixing drive mechanism 514, a second process drive It includes a mechanism 516, a third process drive mechanism 518, and a drive frame 600B for the collar. This collar drive unit 500B is attached to the rear end (back surface) of the resin frame 90.

The second process drive mechanism 516 applies the rotational driving force from the second drive source 504 to cyan (C), magenta (M), and yellow (Y) among various rotating bodies included in the color image forming section 30B. This is a mechanism for transmitting information to a rotating body included in the image station.

The third process drive mechanism 518 applies the rotational driving force from the third drive source 506 to the rotating body included in the black (K) image station among the various rotating bodies included in the color image forming section 30B, and to the intermediate rotating body included in the black (K) image station. This is a mechanism for transmitting the image to the transfer belt unit 70 (drive roller 74).

That is, the rotational driving force of the second driving source 504 is transmitted to the rotating bodies included in the cyan (C), magenta (M), and yellow (Y) image stations, and the rotational driving force of the third driving source 506 is The signal is transmitted to the rotating body and drive roller 74 included in the black (K) image station. Further, in the third embodiment, the rotational driving force of the first driving source 502 is transmitted only to the conveyance driving mechanism 510 and the fixing driving mechanism 514.

Next, the configuration of the color drive frame 600B will be described. The collar drive frame 600B includes a first support frame 602, a collar positioning frame 700B, and a second support frame 800. Note that the color drive frame 600B can use the same first support frame 602 included in the monochrome drive frame 600A (same as the drive frame 600 of the first embodiment).

However, in the third embodiment, the first support frame 602 supports the first drive source 502, the third drive source 506, the transport drive mechanism 510, the third process drive mechanism 518, and the fixing drive mechanism 514.

Further, although the description was omitted in the first embodiment, as shown in FIG. 27, the first support frame 602 includes a third positioning and fixing part 608 and a fourth positioning and fixing part 610. However, the third positioning fixing section 608 and the fourth positioning fixing section 610 are located outside the third process drive mechanism 518 and the fixing drive mechanism 514 in the left-right direction, and on the opposite side (left end) of the first positioning fixing section 604. established in

The third positioning fixing part 608 includes a fitting protrusion 6080 that protrudes toward the rear, and a screw hole 6082 into which the second support frame fixing screw 800a is fixed. Further, the fourth positioning fixing part 610 includes a fitting protrusion 6100 that protrudes toward the rear, and a screw hole 6102 into which the second support frame fixing screw 800a is fixed.

As shown in FIGS. 26 and 27, the collar positioning frame 700B is formed to extend in the left-right direction, and includes the transport frame engaging portion 702 and the first positioning fixing portion 704 described in the first embodiment. , further including a third positioning fixing part 708. Note that the collar positioning frame 700B does not include the second positioning fixing section 706 described in the first embodiment. Further, the collar positioning frame 700B is attached to the back surface of the resin frame 90 (transport frame 100).

The third positioning fixing section 708 is provided on the opposite side (left end portion) of the first positioning fixing section 704 in the left-right direction. The third positioning fixing part 708 includes a fitting hole 7080 corresponding to a fitting protrusion 8060 described later, and fastening holes 7082 and 7084 formed at positions corresponding to two screw holes 8062 and 8064.

As shown in FIGS. 26 and 27, the second support frame 800 is detachably attached to the back side of the first support frame 602. That is, the collar positioning frame 700B and the second support frame 800 are provided so as to sandwich the first support frame 602 from the front and rear. The second support frame 800 also supports the second drive source 504 and the second process drive mechanism 516.

Furthermore, the second support frame 800 includes a first positioning and fixing part 802 , a second positioning and fixing part 804 , and a third positioning and fixing part 806 .

However, the first positioning fixing part 802 and the second positioning fixing part 804 are attached to one end (the right end in this example) of the second support frame 800 in the longitudinal direction (left and right direction) of the collar positioning frame 700B. provided. Further, the third positioning and fixing part 806 is provided at the other end (the left end in this embodiment) of the second support frame 800 in the left-right direction. Furthermore, the first positioning fixing part 802 is provided at one end (the upper end in this example) of the second support frame 800 in the vertical direction, and the second positioning fixing part 804 is provided in the second support frame 800 in the vertical direction. 800 (lower end in this embodiment).

The first positioning fixing part 802 is provided at a position corresponding to the third positioning fixing part 608 of the first support frame 602, and has a fitting hole 8020 corresponding to the fitting protrusion 6080 of the third positioning fixing part 608, and a fitting hole 8020 corresponding to the fitting protrusion 6080 of the third positioning fixing part 608. 3. A fastening hole 8022 formed at a position corresponding to the screw hole 6082 of the third positioning fixing part 608 is included.

The second positioning fixing part 804 is provided at a position corresponding to the fourth positioning fixing part 610 of the first support frame 602, and has a fitting hole 8040 corresponding to the fitting protrusion 6100 of the fourth positioning fixing part 610, and a fitting hole 8040 corresponding to the fitting protrusion 6100 of the fourth positioning fixing part 610. 4, and a fastening hole 8042 formed at a position corresponding to the screw hole 6102 of the positioning fixing part 610.

Then, the fitting protrusion 6080 and the fitting hole 8020 are fitted, and the fitting protrusion 6100 and the fitting hole 8040 are fitted, so that the position of the second support frame 800 with respect to the first support frame 602 is changed. It's decided. Further, the second support frame 800 is attached to the first support frame 602 by fixing the second support frame fixing screws 800a to the screw holes 6082, 6102 through the fastening holes 8022, 8042.

The third positioning fixing part 806 is provided at a position corresponding to the third positioning fixing part 708 of the collar positioning frame 700B, and corresponds to the fitting hole 7080 of the third positioning fixing part 708, and has a fitting hole that protrudes forward. It includes a protrusion 8060 and screw holes 8062 and 8064 formed at positions corresponding to the fastening holes 7082 and 7084 of the third positioning fixing part 708 .

The fitting protrusion 8060 and the fitting hole 7080 fit together, thereby determining the position of the second support frame 800 with respect to the collar positioning frame 700B. Further, the second support frame 800 is attached to the collar positioning frame 700B by fixing the second support frame fixing screws 700a to the screw holes 8062, 8064 through the fastening holes 7082, 7084.

As described above, the first support frame 602, the collar positioning frame 700B, and the second support frame 800 are attached to each other to configure the collar drive frame 600B.

As described above, the same first support frame 602 can be used for the monochrome drive frame 600A and the color drive frame 600B. Then, by selectively attaching the monochrome positioning frame 700A, the color positioning frame 700B, and the second support frame 800 to the first support frame 602, the specifications of the drive unit 500 can be changed. This is because the first support frame 602 is provided with mounting holes according to each specification.

As shown in FIGS. 28(A) and 28(B), the first support frame 602 is provided with a first mounting hole 6020, a second mounting hole 6022, and a third mounting hole 6024. For example, in the monochrome drive unit 500A, the first drive source 502 is attached to the third attachment hole 6024, and the first attachment hole 6020 and the second attachment hole 6022 are not used. On the other hand, in the color drive unit 500B, the first drive source 502 is attached to the first attachment hole 6020, the third drive source 506 is attached to the second attachment hole 6022, and the third attachment hole 6024 is not used.

In this way, the first support frame 602 is provided with a motor mounting hole in advance according to the expected specifications. Although a detailed explanation will be omitted, it is assumed that the first support frame 602 has not only a mounting hole for the motor, but also mounting holes and work holes for mounting shafts (rotation shafts) such as pulleys and gears. It is provided in advance according to the specifications of the image forming apparatus 10.

Next, the positioning structure of each photosensitive drum 36 and the positioning structure of the intermediate transfer belt unit 70 in the color image forming section 30B will be described with reference to FIGS. 26, 29, and 30.

As shown in FIG. 26, a bearing guide member 750 for the transfer unit and a bearing guide member 752 for the photoreceptor drum, each made of a resin material, are attached to the front surface of the color positioning frame 700B. The transfer unit bearing guide member 750 is provided in front of the transfer unit drive gear (transfer unit drive gear) included in the third process drive mechanism 518. The bearing guide member 752 for the photoreceptor drum includes four bearing guide members 752Y, 752M, 752C, and 752K to correspond to the image stations of each color. Each of the bearing guide members 752Y, 752M, 752C, and 752K is provided in front of a gear for driving a photoreceptor drum of each color (a drive gear for the photoreceptor drum).

Further, the bearing guide member 750 for the transfer unit has a substantially cylindrical bearing guide portion 7500 that is formed coaxially with the central axis of the drive gear for the transfer unit and protrudes forward. The photoreceptor drum bearing guide member 752 has a substantially cylindrical bearing guide portion 7520 that is formed coaxially with the central axis of the photoreceptor drum drive gear and protrudes forward.

As shown in FIG. 30, the bearing 74a on the back side of the drive roller 74 of the intermediate transfer belt unit 70 is fitted into the bearing guide part 7500 of the bearing guide member 750 for the transfer unit, so that the drive roller 74 The position of the rear end of the intermediate transfer belt unit 70 is determined around the drive shaft. Arrow A in the figure indicates the mounting direction of the intermediate transfer belt unit 70.

Furthermore, a positioning portion 82 for a color positioning frame 700B is provided at the front end of the intermediate transfer belt unit 70. The positioning portions 82 are provided at both ends of the intermediate transfer belt unit 70 in the left-right direction. The positioning portion 82 is, for example, a combination of a fitting protrusion and a fitting hole, and one of the fitting protrusion and the fitting hole is provided at the front end of the intermediate transfer belt unit 70, and the other is provided on the color positioning frame 700B. It will be done. This positioning portion 82 determines the position of the front end of the intermediate transfer belt unit 70.

As shown in FIG. 29, the bearings 36b of the photoconductor drums 36 included in the image stations of each color are fitted into the bearing guide portion 7520 of the photoconductor drum bearing guide member 752, thereby driving the photoconductor drums 36. The position of the rear end of each photoreceptor drum 36 is determined around the axis.

Further, as shown in FIGS. 29 and 30, a front side positioning member 754 is provided in front of each photoreceptor drum 36. As shown in FIGS. The front side positioning member 754 includes a plurality of positioning parts 756 corresponding to each of the photoreceptor drums 36 included in the color image station, and a rotation shaft part 758.

The rotation shaft portion 758 rotatably supports both left and right ends of the front side positioning member 754 about a rotation shaft extending in the left-right direction. Note that both of the rotating shaft portions 758 may be attached to the color process frame 200B, or one of the rotating shaft portions 758 may be attached to the color process frame 200B, and the other may be attached to the conveyance frame 100. It's okay.

The plurality of positioning portions 756 are through holes provided at positions corresponding to the shaft covers 36d provided at the front end portions of the drive shafts 36a of each photoreceptor drum 36. By fitting the shaft cover 36d of each photoreceptor drum 36 into each positioning portion 756, the position of the front end of each color photoreceptor drum 36 (image station) is determined. That is, the distance between the photosensitive drums 36 included in the image stations of each color is determined (managed).

According to the third embodiment configured as described above, both the monochrome drive unit 500A and the color drive unit 500B each having a drive mechanism are connected to one surface of the resin frame 90 (resin frame body). Since the positioning frame 700 is attached to the rear surface of the resin frame, it is possible to improve workability when attaching the drive unit to the resin frame.

In other words, it is possible to improve the workability of attaching the sheet metal members that support the drive mechanisms constituting each drive unit to the resin frame 90.

Since the positioning frame 700 has positioning parts 710, 750, and 752 in which the process unit 68 is positioned, it supports the rotating body with high precision with respect to the resin frame 90, and reliably transmits the driving force to the rotating body. It is possible to improve the workability of attaching the sheet metal member that supports the drive mechanism.

Further, according to the third embodiment, the process frame 200 with different specifications and the drive unit 500 with different specifications are selectively provided in accordance with the specifications of the image forming apparatus 10, so that the specifications of the apparatus can be easily changed. can do. Specifically, the transport frame 100 and the fixing frame 300 can be used regardless of their specifications, and the specifications of the resin frame 90 can be changed simply by changing the process frame 200. Further, the first support frame 602 included in the drive unit 500 can be used regardless of the specifications, and the specifications of the drive frame 600, that is, the drive unit 500 can be changed by simply changing the positioning frame 700 attached to the first support frame 602. be able to. In other words, it is possible to improve the workability of attaching the sheet metal member that supports the drive mechanism according to the specifications of the resin frame to the resin frame. In particular, even if the specifications of the resin frame (frame) change, the sheet metal parts that support the drive mechanism that can accurately support the rotating body and reliably transmit the driving force to the rotating body can be easily assembled into the resin frame (frame). Can be installed to.

In each of the embodiments described above, the image forming apparatus is configured as a multifunction device, but the image forming apparatus of the present invention may also be configured as a printer, a copying machine, or a facsimile machine.

Further, the specific shapes and the like mentioned in the above-mentioned embodiments are merely examples, and can be changed as appropriate depending on the actual product.

10... Image forming apparatus 12... Housing 30... Image forming section 56... Registration roller 100... Conveyance frame 104... Front side frame positioning section 106... Back side frame positioning section 200... Process frame 204... Front side frame positioning section 206... Back side Side frame positioning section 300...Fixing frame

Claims (12)

An image forming apparatus comprising a frame supporting a paper transport section including a registration roller that adjusts the transport timing of the paper, and an image forming section that forms an image on the paper transported by the paper transport section, the image forming apparatus comprising:
The frame body is
a resin transport frame that supports the paper transport section;
a process frame made of resin that is attached to the downstream side of the conveyance frame in the paper conveyance direction and supports the image forming section; and a process frame that is provided at a position where the conveyance frame and the process frame are engaged and that drives the registration rollers. An image forming apparatus including a first positioning section provided coaxially with the shaft. The first positioning part is provided on the transport frame and engages with a first engaging part formed around the drive shaft of the registration roller, and the first engaging part that is provided on the process frame. The image forming apparatus according to claim 1, further comprising a second engaging portion. The conveyance frame includes a bearing portion that supports a drive shaft of the registration roller,
The first engagement part has an arcuate first engagement surface formed coaxially with the bearing part,
The image forming apparatus according to claim 2, wherein the second engaging portion has a second engaging surface that engages with the first engaging surface. a fixing unit that is provided downstream of the image forming unit in the paper conveyance direction and heats and fixes the image formed on the paper;
a discharge section provided downstream of the fixing section in the paper conveyance direction and configured to discharge the paper out of the apparatus;
The apparatus further includes: a fixing frame made of resin that is attached to the downstream side of the conveyance frame in the paper conveyance direction and supports the fixing section and the discharge section; and a second positioning section that positions the fixing frame with respect to the conveyance frame. An image forming apparatus according to any one of claims 1 to 3. The image forming apparatus according to claim 4, wherein each of the transport frame, the process frame, and the fixing frame is formed of different types of resin materials. The second positioning unit further includes a metal connecting member fixed to each of the transport frame and the fixing frame and for positioning the fixing frame with respect to the transport frame. image forming device. The second positioning portion is provided on a second protrusion provided on the transport frame, a third protrusion provided on the fixing frame at a position a predetermined distance from the second protrusion, and the connection member, The image forming apparatus according to claim 6, comprising: a second fitting part that fits into the second protrusion; and a third fitting part provided on the connecting member and fits into the third protrusion. . further comprising a first drive mechanism that applies rotational driving force to the paper transport section and the image forming section,
The connecting member is disposed on both sides of a paper conveyance path through which the paper is conveyed,
The image forming apparatus according to claim 6 , wherein one of the connecting members supports the first drive mechanism. further comprising a second drive mechanism that transmits rotational driving force to the fixing section and the discharge section,
The image forming apparatus according to claim 8, wherein the second drive mechanism is supported by the one connecting member. The image forming apparatus according to claim 8 or 9, further comprising a fastening section for fastening the one connecting member and the transport frame using a predetermined fixture. 11. The image forming apparatus according to claim 4, wherein the process frame includes a guide section that guides the fixing frame to a predetermined position before the fixing frame is fixed to the transport frame. The image forming apparatus according to any one of claims 1 to 11, wherein the transport frame includes a paper guide section that guides the paper.

Images