Image forming apparatus

Abstract

To provide an image forming apparatus that can prevent the occurrence of an image defect, while preventing an increase in weight of the apparatus and complication of an apparatus mechanism.SOLUTION: An image forming apparatus has: an intermediate transfer unit that transfers toner images carried on image carriers to a transfer target body; a secondary transfer unit that transfers the toner images transferred to the transfer target body to a recording medium; and a fixing unit that fixes the toner images transferred to the recording medium onto the recording medium. The secondary transfer unit and the fixing unit are fixed onto the same drawable frame, and the positions of the intermediate transfer unit and the frame are directly fixed to each other between the intermediate transfer unit and the frame.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] In an electrophotographic image forming apparatus, for example, an electrostatic latent image formed by exposing a charged photoreceptor is developed with toner to form a toner image on the surface of the photoreceptor. After transferring the toner image to an intermediate transfer member, it is transferred from the intermediate transfer member to paper. Thereafter, an image is formed on the paper by performing a fixing process of heating and pressing the toner image on the paper.

[0003] In recent years, image forming apparatuses are generally configured to be largely divided such that a service technician performs process system maintenance support and a user performs paper conveyance system maintenance support. However, especially in the maintenance of the paper conveyance system, a configuration that places more importance on user workability has been adopted, which has caused image defects.

[0004] The following prior art is disclosed in the following patent document. A unit support hook is rotatably provided on a hook support shaft in a transfer conveyance unit including a secondary transfer roller. The secondary transfer roller is opposed to a secondary transfer counter roller provided in an intermediate transfer belt unit via an intermediate transfer belt, and the unit support hook is engaged with both ends of the rotation shaft of the secondary transfer counter roller, respectively. Thereby, the transfer conveyance unit is held by the intermediate transfer belt unit such that the rotation axis of the secondary transfer roller, the rotation axis of the secondary transfer counter roller, and the hook support shaft are parallel and included in the same plane. With such a configuration, since a rotational moment due to the reaction force of the nip pressure of the secondary transfer roller does not occur, it is possible to prevent the occurrence of transfer failure due to deformation of the transfer conveyance unit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, although the above prior art enables highly accurate positioning between the intermediate transfer portion and the secondary transfer roller, the positional relationship with each unit such as a fixing unit disposed upstream and downstream in the paper conveyance direction from these may collapse, causing wrinkles or the like, and there is a possibility of causing image defects. Further, as a countermeasure, if the entire gantry on which each unit including the secondary transfer unit is disposed is fixed in position, it will lead to an increase in the weight of the apparatus, an increase in the work load when removing and pulling out the unit, and a complication of the mechanism for making the unit pull-out possible.

[0007] The present invention has been made to solve such problems. That is, an object of the present invention is to provide an image forming apparatus capable of preventing the occurrence of image defects while suppressing an increase in the weight of the apparatus and complication of the apparatus mechanism.

MEANS FOR SOLVING THE PROBLEMS

[0008] The above problems of the present invention are solved by the following means.

[0009] (1) An intermediate transfer portion that transfers a toner image carried on an image carrier to a transfer medium, a secondary transfer portion that transfers the toner image transferred to the transfer medium to a recording medium, and a fixing portion that fixes the toner image transferred to the recording medium on the recording medium, wherein the secondary transfer portion and the fixing portion are fixed on the same pull-out gantry, and the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry, an image forming apparatus.

[0010] (2) By pressing the secondary transfer roller of the secondary transfer unit and the intermediate transfer roller of the intermediate transfer unit into contact with each other, and directly fixing the rotation axes of the secondary transfer roller and the intermediate transfer roller to be rotatable with respect to each other, the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. The image forming apparatus according to (1) above.

[0011] (3) The image forming apparatus according to (1) or (2) above, further comprising a resist unit fixed to the gantry.

[0012] (4) At least between the fixing unit and the secondary transfer unit, predetermined parts of the intermediate transfer unit and predetermined parts of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. The image forming apparatus according to any one of (1) to (3) above.

[0013] (5) At least between the resist unit and the secondary transfer unit, predetermined parts of the intermediate transfer unit and predetermined parts of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. The image forming apparatus according to (3) above.

[0014] (6) At least at two locations, between the fixing unit and the secondary transfer unit and between the resist unit and the secondary transfer unit, predetermined parts of the intermediate transfer unit and predetermined parts of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. The image forming apparatus according to (3) above.

[0015] (7) At two locations, on the downstream side of the fixing unit and on the upstream side of the resist unit, predetermined parts of the intermediate transfer unit and predetermined parts of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. The image forming apparatus according to (3) above.

[0016] (8) On the side of the intermediate transfer unit with respect to the conveyance path of the recording medium, a predetermined component of the intermediate transfer unit and a predetermined component of the mount are directly fixed to each other, whereby the positions of the intermediate transfer unit and the mount are directly fixed to each other between the intermediate transfer unit and the mount, the image forming apparatus according to any one of (1) to (7) above.

[0017] (8) The roller, which is a component of the mount, is regulated by the rail, which is a component of the intermediate transfer unit, whereby the positions of the intermediate transfer unit and the mount are directly fixed to each other between the intermediate transfer unit and the mount, the image forming apparatus according to any one of (1) to (8) above.

[0018] (10) The roller, which is a component of the intermediate transfer unit, is regulated by the rail, which is a component of the mount, whereby the positions of the intermediate transfer unit and the mount are directly fixed to each other between the intermediate transfer unit and the mount, the image forming apparatus according to any one of (1) to (8) above.

[0019] (11) At two locations in either one of the space between the fixing unit and the secondary transfer unit and the space between the resist unit and the secondary transfer unit, the roller, which is a component of the intermediate transfer unit, is regulated by the rail, which is a component of the mount, and at one location in the other, the roller, which is a component of the intermediate transfer unit, is regulated by the rail, which is a component of the mount, whereby the positions of the intermediate transfer unit and the mount are directly fixed to each other between the intermediate transfer unit and the mount, the image forming apparatus according to (6) above.

[0020] (12) The shaft, which is a component of the intermediate transfer unit, is regulated by the rail, which is a component of the mount, whereby the positions of the intermediate transfer unit and the mount are directly fixed to each other between the intermediate transfer unit and the mount, the image forming apparatus according to any one of (1) to (8) above.

[0021] (13) The position of the intermediate transfer unit and the pedestal is directly fixed to each other between the intermediate transfer unit and the pedestal by restricting the shaft, which is a component of the pedestal, by a rail, which is a component of the intermediate transfer unit. The image forming apparatus according to any one of (1) to (8) above.

[0022] (14) The component of the pedestal is located above the component of the intermediate transfer unit in the vertical direction, and the component of the intermediate transfer unit is located below the component of the pedestal in the vertical direction. The image forming apparatus according to any one of (9), (10), (12), and (13) above.

Advantages of the Invention

[0023] Fix the secondary transfer unit and the fixing unit on the same pull-out pedestal, and directly fix the positions of the intermediate transfer unit and the pedestal to each other between the intermediate transfer unit and the pedestal. Thereby, by ensuring the positional accuracy of the secondary transfer unit and the fixing unit of the paper conveyance system with respect to the intermediate transfer unit, it is possible to prevent the occurrence of image defects while suppressing an increase in the weight of the apparatus and the complication of the apparatus mechanism.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0025] Hereinafter, with reference to the drawings, an image forming apparatus according to an embodiment of the present invention will be described. In the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0026] (First Embodiment) FIG. 1 is a schematic diagram showing the configuration of the image forming apparatus 100. FIG. 2 is a block diagram showing the configuration of the image forming apparatus 100.

[0027] The image forming apparatus 100 includes a control unit 110, a storage unit 120, a communication unit 130, an operation display unit 140, an image reading unit 150, an image control unit 160, and an image forming unit 170. These components are connected to each other communicably by a bus. The image forming apparatus 100 may be configured by an MFP (MultiFunction Peripheral).

[0028] The control unit 110 includes a CPU (Central Processing Unit) and various memories, and controls each of the above units and performs various arithmetic processes according to a program.

[0029] The storage unit 120 is composed of an SDD (Solid State Drive) or an HDD (Hard Disc Drive), etc., and stores various programs and various data.

[0030] The communication unit 130 is an interface for communicating between the image forming apparatus 100 and an external device. As the communication unit 130, a network interface according to a standard such as Ethernet (registered trademark), SATA, IEEE1394, etc. is used. Also, as the communication unit 130, various local connection interfaces such as a wireless communication interface such as Bluetooth (registered trademark), IEEE802.11, etc. are used.

[0031] The operation display unit 140 includes a touch panel, a numeric keypad, a start button, a stop button, etc., and is used for displaying various information and inputting various instructions.

[0032] The image reading unit 150 has a light source such as a fluorescent lamp and an imaging device such as a CCD (Charge Coupled Device) image sensor. The image reading unit 150 irradiates light from a light source onto a document set at a predetermined reading position, photoelectrically converts the reflected light with the imaging device, and generates image data from the electrical signal.

[0033] The image control unit 160 performs layout processing and rasterization processing on print data included in a print job, etc. received by the communication unit 130, and generates image data in bitmap format.

[0034] A print job is a general term for print commands to the image forming apparatus 100 and includes print data and print settings. The print data is the data of the document to be printed, and the print data may include various types of data such as image data, vector data, and text data. Specifically, the print data may be PDL (Page Description Language) data, PDF (Portable Document Format) data, or TIFF (Tagged Image File Format) data. The print settings are settings related to image formation on the paper 900 and include various settings such as the number of pages, the number of printed copies, the paper type, the selection of color or monochrome, and page layout.

[0035] The image forming unit 170 includes an image forming section 40, a fixing section 50, a paper feeding section 60, and a paper conveyance section 70. As will be described later, the primary transfer roller 44, the intermediate transfer belt 43, and the intermediate transfer roller 46 of the image forming section 40 are mounted in the housing of the intermediate transfer section to constitute the intermediate transfer unit 810 (see FIG. 4 etc.). The secondary transfer roller 45 constitutes the secondary transfer unit 820 (also referred to as the secondary transfer section). The fixing section 50 constitutes the fixing unit 830 by mounting each of its components in the housing for the fixing section 50. The registration roller 71 of the paper conveyance section 70 constitutes the registration unit 840 by being mounted in the housing of the registration section.

[0036] The image forming section 40 includes image forming units 41Y, 41M, 41C, and 41K corresponding to toners of respective colors of Y (yellow), M (magenta), C (cyan), and K (black). By each of the image forming units 41Y, 41M, 41C, and 41K, a toner image is formed on the photoreceptor drum 42 through processes of charging, exposure, and development based on image data. The photoreceptor drum 42 constitutes an image carrier. The exposure is performed by scanning the photoreceptor drum 42 with laser light. The toner image formed on the photoreceptor drum 42 is sequentially superimposed and primarily transferred onto the intermediate transfer belt 43 by an electrostatic force due to a transfer voltage controlled at a constant voltage applied to the primary transfer roller 44. The intermediate transfer belt 43 constitutes a transfer body. Thereby, a color toner image is held on the intermediate transfer belt 43. The color toner image on the intermediate transfer belt 43 is secondarily transferred onto the paper 900 by the secondary transfer roller 45. The primary transfer roller 44, the intermediate transfer belt 43, and the intermediate transfer roller 46 constitute an intermediate transfer section. The primary transfer roller 44, the intermediate transfer belt 43, and the intermediate transfer roller 46, which are components of the intermediate transfer section, are mounted in the housing of the intermediate transfer section to constitute an intermediate transfer unit 810 (see FIG. 4 etc.). The secondary transfer roller 45 constitutes a secondary transfer section (also referred to as a secondary transfer unit 820 (see FIG. 4 etc.)).

[0037] The fixing section 50 includes a fixing roller 51a and a pressure roller 52. By pressing the fixing roller 51a and the pressure roller 52 against each other, a fixing nip is formed between the fixing roller 51a and the pressure roller 52. The fixing section 50 heats and presses the paper 900 conveyed to the fixing nip, and rotates the fixing roller 51a and the pressure roller 52 to melt and fix the toner image on the paper 900 onto the surface of the paper 900. Each component of the fixing section 50 is mounted in a housing for the fixing section 50 to constitute a fixing unit 830 (see FIG. 4 etc.).

[0038] The paper feeding section 60 has a plurality of paper feeding trays 61, 62, and feeds the papers 900 accommodated in the paper feeding trays 61, 62 one by one to the downstream paper conveyance path.

[0039] The sheet conveyance unit 70 has a plurality of conveyance rollers for conveying the sheet 900, and conveys the sheet 900 between the image forming unit 40, the fixing unit 50, and the sheet feeding unit 60. The plurality of conveyance rollers includes a registration roller 71 for correcting the inclination of the sheet 900 and a loop roller 72 for forming a predetermined amount of loop in the sheet 900. The registration roller 71 constitutes the registration unit. The registration roller 71 constitutes the registration unit 840 by being mounted in the housing of the registration unit.

[0040] The sheet conveyance unit 70 discharges the sheet 900 on which an image has been formed to the discharge tray 90.

[0041] Figs. 3 and 4 are front views showing the arrangement configuration of each unit of the image forming apparatus 100. Fig. 5 is a perspective view showing the arrangement configuration of each unit of the image forming apparatus 100. Fig. 6 is a perspective view of the base 800 of the image forming apparatus 100. Hereinafter, the vertical direction is the Z direction, the front and rear directions of the image forming apparatus 100 are the Y direction, and the direction orthogonal to these Y and Z directions is the X direction. In Fig. 4, the process door 850 is not shown and the intermediate transfer unit 810 etc. are visualized.

[0042] As shown in Figs. 3 to 5, the secondary transfer unit 820 (secondary transfer roller 45) and the fixing unit 830 are fixed on the same pull-out base 800. The registration unit 840 can be further fixed on the base 800.

[0043] The positions of the intermediate transfer unit 810 and the base 800 are directly fixed to each other between the intermediate transfer unit 810 and the base 800. That is, the positions of the intermediate transfer unit 810 and the base 800 are fixed to each other between the intermediate transfer unit 810 and the base 800 without passing through the housing (skeleton) of the image forming apparatus 100. Specifically, a roller 802 rotatably provided on the wall surface of a wall 801 extending perpendicularly to the X direction of the base 800 is restricted by a rail 811 extending in the Y direction of the intermediate transfer unit 810. At this time, one of the rail 811 (intermediate transfer unit 810) and the roller 802 can be biased toward the other by gravity or an elastic force of an elastic member (not shown) or an elastic roller or the like. Thereby, the positions of the intermediate transfer unit 810 and the base 800 are directly fixed to each other between the intermediate transfer unit 810 and the base 800. The roller 802 constitutes a component of the base 800. The rail 811 constitutes a component of the intermediate transfer unit 810 (intermediate transfer section). Hereinafter, the position where the positions of the intermediate transfer unit 810 and the base 800 are directly fixed to each other between the intermediate transfer unit 810 and the base 800 is also simply referred to as the "fixed position".

[0044] In the example of FIG. 4 and the like, at the fixed position, the roller 802, which is a component of the base 800, is located above in the vertical direction (Z direction) with respect to the rail 811, which is a component of the intermediate transfer unit 810, and the rail 811 is located below in the vertical direction with respect to the roller 802. The weight of the base 800 and the secondary transfer unit 820, fixing unit 830, and resist unit 840 on the base 800 is applied to the roller 802. The weight of the intermediate transfer unit 810 is applied to the rail 811. Since the weight applied to the roller 802 is heavier than the weight applied to the rail 811, the height direction positions of the respective units can be stabilized by positioning one component with a relatively heavy weight above the other component in the vertical direction.

[0045] As described above, the roller 802 and the rail 811 are provided on the base 800 (specifically, the wall 801) and the intermediate transfer unit 810, respectively. However, instead of this, the rail 811 may be provided on the base 800 (specifically, the wall 801), and the roller 802 may be provided on the intermediate transfer unit 810.

[0046] The intermediate transfer unit 810 can be rotatably supported by a rear panel (not shown) and a process door 850 such that the rotation axes of at least two rollers including the intermediate transfer roller 46. Specifically, the intermediate transfer roller 46 and the like can be rotatably supported, for example, by inserting the rotation axis into a hole provided in the process door 850 (and a hole provided in the rear panel (see FIGS. 3 and 5)). Thereby, the intermediate transfer unit 810 can be positioned with respect to the housing 890 of the image forming apparatus 100. Similarly, the photosensitive drum 42 can also be rotatably supported by inserting the rotation axis into a hole provided in the process door 850 (and a hole provided in the rear panel (see FIGS. 3 and 5)). Thereby, the photosensitive drum 42 can be positioned with respect to the housing 890 of the image forming apparatus 100. Thus, the positional accuracy between the intermediate transfer unit 810 and the photosensitive drum 42 is ensured.

[0047] The fixed position can be between the fixing unit 830 and the secondary transfer unit 820 (in the paper conveyance direction, or the X direction (horizontal direction)). That is, at least between the fixing unit 830 and the secondary transfer unit 820, they can be directly fixed to each other between the roller 802 of the gantry 800 and the rail 811 of the intermediate transfer unit 810. Thereby, by making the fixed position close to the secondary transfer roller 45 and the intermediate transfer roller 46, the positional accuracy between these rollers can be improved, and the accuracy of the fixing position by the fixing unit 830 can be improved.

[0048] The fixed position can be on the intermediate transfer unit 810 side from the conveyance path of the paper 900. That is, as shown in FIG. 4 and the like, for example, the position where the roller 802 of the gantry 800 is regulated by the rail 811 of the intermediate transfer unit 810 can be on the intermediate transfer unit 810 side from the conveyance path of the paper 900. Thereby, it is possible to suppress the complication of the mechanism for making the gantry 800 pull-out possible leaving the intermediate transfer unit 810.

[0049] As shown in FIG. 6, a paper passage hole 805 for passing the paper 900 is provided in the wall 801 of the gantry 800.

[0050] FIG. 7 is a perspective view of the image forming apparatus 100 with the gantry 800 pulled out.

[0051] After releasing the lock mechanism, the gantry 800 can be pulled forward (in the Y direction) along the side wall of the housing of the image forming apparatus 100. At this time, the gantry 800 can be easily pulled out from the image forming apparatus 100 (the main body) by the rotation of the roller 802 along the rail 811. By pulling out the gantry 800, maintenance of the secondary transfer unit 820, the fixing unit 830, and the registration unit 840 on the gantry 800 can be easily performed.

[0052] FIG. 8 is a perspective view of the image forming apparatus 100 with the intermediate transfer unit 810 pulled out. FIG. 9 is a perspective view of the intermediate transfer unit 810.

[0053] After releasing the lock mechanism, the intermediate transfer unit 810 can be pulled forward (in the Y direction) along the side wall of the housing of the image forming apparatus 100. At this time, the intermediate transfer unit 810 can be easily pulled out from the image forming apparatus 100 by the rotation of the roller 802 along the rail 811. Tapers for facilitating the insertion and removal of the intermediate transfer unit 810 into and from the image forming apparatus may be provided at both ends of the rail 811. Further, when inserting and removing the intermediate transfer unit 810 into and from the image forming apparatus, a mechanism for lifting the gantry 800 may be provided by rotating a lever (not shown) of the lock mechanism provided on the process door 850. After inserting the intermediate transfer unit 810 into the image forming apparatus, the gantry 800 is biased and fixed to the intermediate transfer unit 810 side by rotating the lever of the lock mechanism. By pulling out the intermediate transfer unit 810, maintenance of the intermediate transfer unit 810 can be easily performed.

[0054] (Second Embodiment) The second embodiment will be described. The difference between this embodiment and the first embodiment is as follows. In the first embodiment, the fixed position is between the fixing unit 830 and the secondary transfer unit 820. On the other hand, in this embodiment, the fixed position is between the resist unit 840 and the secondary transfer unit 820. Since other points are the same as those in the first embodiment, duplicate explanations will be omitted.

[0055] FIG. 10 is a front view showing the arrangement configuration of each unit of the image forming apparatus 100. FIG. 11 is a perspective view of the base 800 of the image forming apparatus 100.

[0056] As shown in FIG. 10, a roller 802 rotatably provided on the wall surface of a wall 801 extending vertically in the X direction of the base 800 is restricted by a rail 811 extending in the Y direction of the intermediate transfer unit 810. Thereby, the positions of the intermediate transfer unit 810 and the base 800 are directly fixed to each other between the intermediate transfer unit 810 and the base 800.

[0057] The fixed position can be between the resist unit 840 and the secondary transfer unit 820 (in the paper conveyance direction or the X direction (horizontal direction)). That is, at least between the resist unit 840 and the secondary transfer unit 820, they can be directly fixed to each other between the roller 802 of the base 800 and the rail 811 of the intermediate transfer unit 810. Thereby, by setting the position for fixing the base 800 and the intermediate transfer unit 810 near the secondary transfer roller 45 and the intermediate transfer roller 46, the positional accuracy between these rollers can be improved, and the accuracy of the resist position by the resist unit 840 can be improved.

[0058] The fixed position can be on the intermediate transfer unit 810 side from the conveyance path of the sheet 900. That is, as shown in FIG. 10 and the like, for example, the position where the roller 802 of the base 800 is restricted by the rail 811 of the intermediate transfer unit 810 can be on the intermediate transfer unit 810 side from the conveyance path of the sheet 900. Thereby, it is possible to suppress the complication of the mechanism for making the base 800 pullable leaving the intermediate transfer unit 810.

[0059] FIG. 12 is a perspective view of the image forming apparatus 100 with the mount 800 pulled out.

[0060] The mount 800 can be pulled out along the side wall of the housing of the image forming apparatus 100. At this time, the mount 800 can be easily pulled out from the image forming apparatus 100 by the roller 802 rotating along the rail 811. By pulling out the mount 800, maintenance of the secondary transfer unit 820, the fixing unit 830, and the registration unit 840 on the mount 800 can be easily performed.

[0061] FIG. 13 is a perspective view of the image forming apparatus 100 with the intermediate transfer unit 810 pulled out. FIG. 14 is a perspective view of the intermediate transfer unit 810.

[0062] The intermediate transfer unit 810 can be easily pulled out from the image forming apparatus 100 by the roller 802 rotating along the rail 811. Tapers for facilitating insertion and extraction of the intermediate transfer unit 810 into and from the image forming apparatus may be provided at both ends of the rail 811. By pulling out the intermediate transfer unit 810, maintenance of the intermediate transfer unit 810 can be facilitated.

[0063] (Third Embodiment) The third embodiment will be described. The difference between this embodiment and the first embodiment is as follows. In the first embodiment, the roller 802 of the mount 800 is regulated by the rail 811 of the intermediate transfer unit 810. Thereby, the positions of the intermediate transfer unit 810 and the mount 800 are directly fixed to each other between the intermediate transfer unit 810 and the mount 800. On the other hand, in this embodiment, the rotary shafts of the secondary transfer roller 45 rotatably fixed to the mount 800 and the intermediate transfer roller 46 of the intermediate transfer unit 810 are directly fixed to each other rotatably. Thereby, the positions of the intermediate transfer unit 810 and the mount 800 are directly fixed to each other between the intermediate transfer unit 810 and the mount 800. Since other points are the same as those of the first embodiment, redundant descriptions are omitted.

[0064] FIG. 15 is a schematic diagram showing the arrangement configuration of each unit of the image forming apparatus 100.

[0065] As shown in FIG. 15, a shaft fixing member 860 is provided on a pedestal 800 so as to be rotatable about a fulcrum 862 in the direction of the arrow. The shaft fixing member 860 is provided with grooves 861 capable of rotatably accommodating the rotating shafts of the secondary transfer roller 45 and the intermediate transfer roller 46, respectively. By rotating the shaft fixing member 860 until the rotating shafts of the secondary transfer roller 45 and the intermediate transfer roller 46 abut against the bottom of the groove 861, respectively, the rotating shafts of the secondary transfer roller 45 and the intermediate transfer roller 46 are accommodated in the groove 861. Thereby, the rotating shafts of the secondary transfer roller 45 and the intermediate transfer roller 46 of the intermediate transfer unit 810 are directly and rotatably fixed to each other. By doing so, the positions of the intermediate transfer unit 810 and the pedestal 800 can be directly fixed to each other between the intermediate transfer unit 810 and the pedestal 800.

[0066] (Modification 1) In the first embodiment, the fixed position is between the fixing unit 830 and the secondary transfer unit 820, and in the second embodiment, the fixed position is between the resist unit 840 and the secondary transfer unit 820. However, the fixed position can be at two locations, between the fixing unit 830 and the secondary transfer unit 820 and between the resist unit 840 and the secondary transfer unit 820. The positional accuracy in the height direction (Z direction), including the positional accuracy between the secondary transfer roller 45 and the intermediate transfer roller 46, may become unstable due to the inclination of the pedestal 800 or the like if there is only one fixed position. In this case, by setting the fixed positions at two locations, between the fixing unit 830 and the secondary transfer unit 820 and between the resist unit 840 and the secondary transfer unit 820, the positional accuracy in the height direction of each unit can be more reliably ensured.

[0067] Also, at one of the two fixed positions, the two rollers 802 are regulated by the rail 811, and at the other, one roller 802 is regulated by the rail 811, so that the positions of the intermediate transfer unit 810 and the gantry 800 can be directly fixed to each other between the intermediate transfer unit 810 and the gantry 800. That is, the rollers 802 can be regulated by the rail 811 at two locations at either one of the space between the fixing unit 830 and the secondary transfer unit 820 and the space between the resist unit 840 and the secondary transfer unit 820, and at one location at the other. Thereby, by three-point support, the positions of the intermediate transfer unit 810 and the gantry 800 are directly fixed to each other between the intermediate transfer unit 810 and the gantry 800, and the positional accuracy between the units can be stably improved.

[0068] (Modification 2) In the first embodiment, the fixed position is between the fixing unit 830 and the secondary transfer unit 820, and in the second embodiment, the fixed position is between the resist unit 840 and the secondary transfer unit 820. In this modification, the fixed positions are two locations on the downstream side in the paper conveyance direction from the fixing unit 830 and on the upstream side in the paper conveyance direction from the resist unit 840. When the width of the gantry 800 is wide, by setting the fixed position at the central part of the gantry 800, the entire gantry 800 is relatively likely to be affected by vibration. By setting the fixed positions as in this modification, at two locations on the downstream side in the paper conveyance direction from the fixing unit 830 and on the upstream side from the resist unit 840, such an influence of vibration can be suppressed.

[0069] (Modification 3) FIGS. 16 and 17 are schematic views showing the arrangement configuration of each unit of the image forming apparatus 100 according to Modification 3.

[0070] In the example of FIG. 16, instead of the roller 802 being restricted by the rail 811 at a fixed position as in the first embodiment, a shaft 812 extending in the Y direction may be provided in the intermediate transfer unit 810, and the shaft 812 may be restricted by a shaft receiving member 803 provided on the gantry 800. The shaft receiving member 803 may be provided with a depression corresponding to the shape of the shaft 812. Thereby, the positions of the intermediate transfer unit 810 and the gantry 800 are directly fixed to each other between the intermediate transfer unit 810 and the gantry 800.

[0071] As shown in the example of FIG. 17, at a fixed position, a shaft 804 extending in the Y direction may be provided on the gantry 800 (specifically, the wall 801), and the shaft 804 may be restricted by a shaft receiving member 813 provided on the intermediate transfer unit 810. The shaft receiving member 813 may be provided with a depression corresponding to the shape of the shaft 804. Thereby, the positions of the intermediate transfer unit 810 and the gantry 800 can be directly fixed to each other between the intermediate transfer unit 810 and the gantry 800.

[0072] The embodiments and modifications of the present invention have the following effects.

[0073] Fix the secondary transfer unit and the fixing unit that can be pulled out on the same gantry, and directly fix the positions of the intermediate transfer unit and the gantry to each other between the intermediate transfer unit and the gantry. Thereby, by ensuring the positional accuracy of the secondary transfer unit and the fixing unit of the paper conveyance system with respect to the intermediate transfer unit, it is possible to prevent the occurrence of image defects while suppressing an increase in the weight of the apparatus and the complication of the apparatus mechanism.

[0074] Furthermore, by pressing the secondary transfer roller of the secondary transfer unit against the intermediate transfer roller of the intermediate transfer unit and directly fixing the rotation axes of the secondary transfer roller and the intermediate transfer roller to be rotatable with respect to each other, the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry. Thereby, it is possible to ensure the positional accuracy of the transfer unit and the fixing unit with respect to the intermediate transfer unit with a simpler configuration.

[0075] Furthermore, fix the resist portion to the gantry. Thereby, the positional accuracy of the transfer portion, the fixing portion, and the resist portion with respect to the intermediate transfer portion can be ensured.

[0076] Furthermore, directly fix the predetermined components of the intermediate transfer portion and the predetermined components of the gantry to each other between at least the fixing portion and the secondary transfer portion, between the predetermined components of the intermediate transfer portion and the predetermined components of the gantry, so as to directly fix the positions of the intermediate transfer portion and the gantry to each other between the intermediate transfer portion and the gantry. Thereby, by making the fixing position close to the intermediate transfer roller and the secondary transfer roller, the positional accuracy between the intermediate transfer roller and the secondary transfer roller can be maintained, and the positional accuracy of the fixing portion can be improved.

[0077] Furthermore, directly fix the predetermined components of the intermediate transfer portion and the predetermined components of the gantry to each other between at least the resist portion and the secondary transfer portion, between the predetermined components of the intermediate transfer portion and the predetermined components of the gantry, so as to directly fix the positions of the intermediate transfer portion and the gantry to each other between the intermediate transfer portion and the gantry. Thereby, by making the fixing position close to the intermediate transfer roller and the secondary transfer roller, the positional accuracy between the intermediate transfer roller and the secondary transfer roller can be maintained, and the positional accuracy of the resist portion can be improved.

[0078] Furthermore, directly fix the predetermined components of the intermediate transfer portion and the predetermined components of the gantry to each other at least at two locations between the fixing portion and the secondary transfer portion and between the resist portion and the secondary transfer portion, between the predetermined components of the intermediate transfer portion and the predetermined components of the gantry, so as to directly fix the positions of the intermediate transfer portion and the gantry to each other between the intermediate transfer portion and the gantry. Thereby, the positional accuracy in the height direction of each part, which is the direction orthogonal to the gantry, can be stably ensured.

[0079] Furthermore, at two locations, one on the downstream side of the fixing unit and the other on the upstream side of the resist unit, the predetermined components of the intermediate transfer unit and the predetermined components of the gantry are directly fixed to each other between the predetermined components of the intermediate transfer unit and the predetermined components of the gantry, thereby directly fixing the positions of the intermediate transfer unit and the gantry to each other between the intermediate transfer unit and the gantry. Thereby, particularly when the width of the gantry is wide, by setting the fixing position at the central portion of the gantry, the influence of vibrations that are relatively easily received can be suppressed.

[0080] Furthermore, on the side of the intermediate transfer unit from the conveyance path of the recording medium, the predetermined components of the intermediate transfer unit and the predetermined components of the gantry are directly fixed to each other between the predetermined components of the intermediate transfer unit and the predetermined components of the gantry, thereby directly fixing the positions of the intermediate transfer unit and the gantry to each other between the intermediate transfer unit and the gantry. Thereby, it is possible to prevent complication of the mechanism when the gantry is made pull-outable while leaving the process unit including the intermediate transfer unit.

[0081] Furthermore, the position of the intermediate transfer unit and the gantry is directly fixed to each other between the intermediate transfer unit and the gantry by restricting the rollers, which are components of the gantry, by the rails, which are components of the intermediate transfer unit. Alternatively, the position of the intermediate transfer unit and the gantry is directly fixed to each other between the intermediate transfer unit and the gantry by restricting the rollers, which are components of the intermediate transfer unit, by the rails, which are components of the gantry. Thereby, the burden on the user in pulling out each unit of relatively large weight can be reduced.

[0082] Furthermore, at two locations in either one of the space between the fixing unit and the secondary transfer unit and the space between the resist unit and the secondary transfer unit, the rollers, which are components of the intermediate transfer unit, are restricted by the rails, which are components of the gantry, and at one location in the other, the rollers, which are components of the intermediate transfer unit, are restricted by the rails, which are components of the gantry, thereby directly fixing the positions of the intermediate transfer unit and the gantry to each other between the intermediate transfer unit and the gantry. Thereby, by three-point support, the burden on the user in pulling out each unit of relatively large weight can be further reduced, and the positional accuracy between the units can be further stably improved.

[0083] Furthermore, the position of the intermediate transfer unit and the mount is directly fixed to each other between the intermediate transfer unit and the mount by regulating a shaft, which is a component of the intermediate transfer unit, by a rail, which is a component of the mount. Alternatively, the position of the intermediate transfer unit and the mount is directly fixed to each other between the intermediate transfer unit and the mount by regulating a shaft, which is a component of the mount, by a rail, which is a component of the intermediate transfer unit. This can reduce the burden on the user when pulling out each unit with a relatively large weight.

[0084] Furthermore, a component of the mount is positioned above in the vertical direction with respect to a component of the intermediate transfer unit, and a component of the intermediate transfer unit is positioned below in the vertical direction with respect to a component of the mount. By fixing the positions of both components with the component of the mount having a relatively large weight above the component of the intermediate part, the relative positional accuracy of both can be further stabilized.

[0085] The present invention is not limited to the above-described embodiments.

[0086] For example, the units fixed to the mount may be only the secondary transfer unit and the fixing unit, or may include units other than the secondary transfer unit, the fixing unit, and the resist unit.

Explanation of Reference Numerals

[0087] 40 Image forming unit, 42 Photoconductor drum, 43 Intermediate transfer belt, 44 Primary transfer roller, 45 Secondary transfer roller, 46 Intermediate transfer roller, 50 Fixing unit, 71 Resist roller, 72 Loop roller, 100 Image forming apparatus, 110 Control unit, 120 Storage unit, 130 Communication unit, 140 Operation display unit, 150 Image reading unit, 160 Image control unit, 170 Image forming unit, 800 Stand, 801 Wall, 802 Roller, 803 Shaft receiving member, 804 Shaft, 810 Intermediate transfer unit, 811 Rail, 812 Shaft, 813 Shaft receiving member, 820 Secondary transfer unit, 830 Fixing unit, 840 Resist unit, 850 Process door, 860 Shaft fixing member, 861 Groove 890 Housing.

Claims

1. An intermediate transfer unit that transfers a toner image carried on an image carrier to a transfer medium, A secondary transfer unit that transfers the toner image transferred to the transfer medium to a recording medium, A fixing unit that fixes the toner image transferred to the recording medium onto the recording medium, and has, The secondary transfer unit and the fixing unit are fixed on the same pull-outable gantry, and the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, an image forming apparatus.

2. By pressing the secondary transfer roller of the secondary transfer unit and the intermediate transfer roller of the intermediate transfer unit into pressure contact, and directly fixing the rotation axes of the secondary transfer roller and the intermediate transfer roller to be rotatable with respect to each other, the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, the image forming apparatus according to claim 1.

3. The image forming apparatus according to claim 1 or 2, further comprising a resist unit fixed on the gantry.

4. At least between the fixing unit and the secondary transfer unit, predetermined components of the intermediate transfer unit and predetermined components of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, the image forming apparatus according to any one of claims 1 to 3.

5. At least between the resist unit and the secondary transfer unit, predetermined components of the intermediate transfer unit and predetermined components of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, the image forming apparatus according to claim 3.

6. At least at two locations, between the fixing unit and the secondary transfer unit and between the resist unit and the secondary transfer unit, predetermined components of the intermediate transfer unit and predetermined components of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, the image forming apparatus according to claim 3.

7. At two locations, downstream of the fixing unit and upstream of the resist unit, predetermined components of the intermediate transfer unit and predetermined components of the gantry are directly fixed to each other, so that the positions of the intermediate transfer unit and the gantry are directly fixed to each other between the intermediate transfer unit and the gantry, the image forming apparatus according to claim 3.

8. In the side closer to the intermediate transfer portion than the conveyance path of the recording medium, a predetermined component of the intermediate transfer portion and a predetermined component of the gantry are directly fixed to each other, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to any one of claims 1 to 7.

9. The roller, which is a component of the gantry, is restricted by the rail, which is a component of the intermediate transfer portion, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to any one of claims 1 to 8.

10. The roller, which is a component of the intermediate transfer portion, is restricted by the rail, which is a component of the gantry, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to any one of claims 1 to 8.

11. At two positions, either between the fixing portion and the secondary transfer portion or between the resist portion and the secondary transfer portion, the roller, which is a component of the intermediate transfer portion, is restricted by the rail, which is a component of the gantry, and at one position on the other side, the roller, which is a component of the intermediate transfer portion, is restricted by the rail, which is a component of the gantry, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to claim 6.

12. The shaft, which is a component of the intermediate transfer portion, is restricted by the rail, which is a component of the gantry, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to any one of claims 1 to 8.

13. The shaft, which is a component of the gantry, is restricted by the rail, which is a component of the intermediate transfer portion, so that the positions of the intermediate transfer portion and the gantry are directly fixed to each other between the intermediate transfer portion and the gantry. The image forming apparatus according to any one of claims 1 to 8.

14. The component of the gantry is located above in the vertical direction with respect to the component of the intermediate transfer portion, and the component of the intermediate transfer portion is located below in the vertical direction with respect to the component of the gantry. The image forming apparatus according to any one of claims 9, 10, 12, and 13.

Images