Image forming apparatus

Abstract

To provide an image forming apparatus in which trouble caused by heat from a power supply unit hardly occurs.SOLUTION: An image forming apparatus has a housing that has a space for in-barrel paper ejection, and a power supply unit that is provided adjacent to the space in the housing.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] An embodiment of the present invention relates to an image forming apparatus, such as a copier or printer, installed in a workplace. [Background technology]

[0002] Image forming devices such as copiers and printers include a scanner that reads an image on an original document, an exposure device that forms an electrostatic latent image on the surface of a photosensitive drum, a developing device that supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum to develop it, a transport device that transports paper to the surface of the photosensitive drum, a transfer device that transfers the toner image formed on the surface of the photosensitive drum to the paper, and a fixing device that fixes the toner image transferred to the paper.

[0003] The image forming apparatus also has a power supply unit equipped with a power supply circuit that supplies power to each component. Since the power supply circuit includes electronic components such as a transformer that become hot, the power supply unit becomes a heat source in the image forming apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-87627 A Summary of the Invention [Problem to be solved by the invention]

[0005] The developing device is equipped with a toner cartridge that contains the toner to be supplied to the photosensitive drum. The toner can melt or stick due to heat. For this reason, if the power supply unit, which is a heat generating source, is located near the toner cartridge, problems such as the toner melting or sticking may occur.

[0006] An object of the present invention is to provide an image forming apparatus which is less susceptible to problems caused by heat from a power supply unit. [Means for solving the problem]

[0007] The image forming apparatus according to the embodiment has a housing having a space for internal paper discharge, and a power supply unit provided in the housing adjacent to the space. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an image forming apparatus according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an image forming section for yellow of the image forming apparatus in FIG. [Diagram 3] 3 is a perspective view of the main part of the image forming apparatus in FIG. 1, as viewed obliquely from the left rear. [Figure 4] FIG. 4 is a perspective view showing a frame of the housing of FIG. [Diagram 5] FIG. 5 is a perspective view showing a state in which a power supply unit is attached to the opening of the frame shown in FIG. [Figure 6] FIG. 6 is a perspective view of the power supply unit attached to the opening in FIG. 5, as viewed from the discharge tray side. [Figure 7] FIG. 7 is a perspective view showing the rear frame of FIG. [Figure 8] FIG. 8 is a partially enlarged perspective view showing a main part of FIG. [Figure 9] FIG. 9 is a diagram showing a power supply circuit board accommodated in the case of the power supply unit of FIG. [Figure 10] FIG. 10 is a perspective view for explaining a heat dissipation path of the power supply unit of FIG. [Figure 11] FIG. 11 is a front view of the ventilation hole in FIG. 10 as viewed from the discharge tray side. [Figure 12] FIG. 12 is a perspective view of the rear frame showing a state in which the board unit is attached to the power supply unit of FIG. [Figure 13] FIG. 13 is a perspective view showing two control boards of the board unit of FIG. [Figure 14]FIG. 14 is a cross-sectional perspective view of the rear frame of FIG. 12 taken along the line of arrows F14-F14. [Figure 15] FIG. 15 is a diagram for explaining the weight balance of the power supply unit in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an image forming apparatus 100 according to an embodiment (hereinafter, simply referred to as the apparatus 100) will be described with reference to the drawings. Note that the scale of each part in each drawing used in the following description of the embodiment may be changed as appropriate. Also, in order to make the description easier to understand, each drawing used in the following description of the embodiment may be shown with the configuration omitted.

[0010] The device 100 is, for example, an MFP (multifunction peripheral). The device 100 has a printing function, a scanning function, a copying function, an erasing function, a facsimile function, and the like. The printing function is a function for forming an image on paper P. The scanning function is a function for reading an image from an original document on which an image has been formed. The copying function is a function for printing an image read from an original document using the scanning function, for example, on paper P using the printing function. The erasing function is a function for erasing an image formed on paper P with erasable toner.

[0011] As shown in Fig. 1, device 100 has a housing 1 that forms the outer shell of the device. Device 100 includes a printer 10, a scanner 20, and an operation panel 30. Device 100 includes printer 10 and scanner 20 inside housing 1, and includes operation panel 30 on the front side of housing 1. In the following description, the front-rear, up-down, left-right directions are defined when device 100 is viewed from the direction shown in Fig. 1.

[0012] Printer 10 includes multiple paper feed cassettes 11, a manual feed tray 12, and multiple paper feed rollers 13. Paper feed cassette 11 stores paper P to be used for printing. Manual feed tray 12 is for manually feeding paper P. Paper feed roller 13 selectively picks up paper P from either paper feed cassette 11 or manual feed tray 12 by rotating.

[0013] The printer 10 includes four toner cartridges 141, 142, 143, and 144, four image forming units 151, 152, 153, and 154, an exposure device 16, a transfer belt 17, a secondary transfer roller 18, and a fixing device 19.

[0014] Toner cartridges 141-144 contain toner to be supplied to image forming units 151-154, respectively. Toner cartridge 141 contains yellow (Y) toner. Toner cartridge 142 contains magenta (M) toner. Toner cartridge 143 contains cyan (C) toner. Toner cartridge 144 contains black (K) toner. The toner color combination is not limited to YMCK, and other color combinations may be used. Furthermore, the toner may be a toner that is erased at a temperature higher than a predetermined temperature.

[0015] The image forming units 151 to 154 receive toner from the toner cartridges 141 to 144, respectively, and form toner images of different colors. The image forming unit 151 forms a yellow (Y) toner image. The image forming unit 152 forms a magenta (M) toner image. The image forming unit 153 forms a cyan (C) toner image. The image forming unit 154 forms a black (K) toner image.

[0016] The image forming units 151 to 154 have the same configuration except for the difference in toner. Therefore, here, the image forming unit 151 for yellow will be described as a representative with reference to FIG. 2, and descriptions of the image forming units 152 to 154 for the other colors will be omitted.

[0017] The yellow image forming section 151 includes a photoconductor drum 41, a charging device 42, a developing device 43, a primary transfer roller 44, a cleaner 45, and a discharging lamp 46.

[0018] The photoconductor drum 41 has a surface that receives the light beam BY irradiated from the exposure device 16. The charging device 42 negatively charges the surface of the photoconductor drum 41. The exposure device 16 forms an electrostatic latent image on the surface of the photoconductor drum 41. The developing device 43 develops the electrostatic latent image on the surface of the photoconductor drum 41 using yellow toner D supplied from the toner cartridge 141. That is, the developing device 43 forms a yellow toner image on the surface of the photoconductor drum 41.

[0019] Image forming unit 151 includes primary transfer roller 44 at a position facing the surface of photoconductor drum 41 with transfer belt 17 sandwiched therebetween. Primary transfer roller 44 generates a transfer voltage between photoconductor drum 41 and primary transfer roller 44. As a result, primary transfer roller 44 transfers (primary transfer) the toner image on the surface of photoconductor drum 41 onto the surface of transfer belt 17 in contact with photoconductor drum 41.

[0020] The cleaner 45 removes the toner remaining on the surface of the photoconductor drum 41. The charge removing lamp 46 removes the charge remaining on the surface of the photoconductor drum 41.

[0021] The exposure device 16 irradiates the surfaces of the photoconductor drums 41 of the image forming units 151, 152, 153, and 154 with light beams BY, BM, BC, and BK in accordance with the input image data. The light beams BY, BM, BC, and BK are based on image data of each color obtained by color-separating the image data into Y, M, C, and K colors, respectively.

[0022] The exposure device 16 emits a light beam BY in accordance with image data of the Y component to form an electrostatic latent image for yellow on the surface of the photoconductor drum 41 of the image forming unit 151. Similarly, the exposure device 16 emits light beams BM, BC, and BK in accordance with image data of the M, C, and K components to form electrostatic latent images for each color on the surfaces of the photoconductor drums 41 of the image forming units 152, 153, and 154.

[0023] The image data input to the exposure device 16 is, for example, image data read from an original document by the scanner 20. Alternatively, the image data input to the exposure device 16 is image data transmitted to the device 100 from a device other than the device 100.

[0024] 1, the transfer belt 17 is endlessly stretched and rotates by rotating a drive roller 171 around which the transfer belt 17 is wound. As the transfer belt 17 rotates, it transports the toner images of each color formed by the image forming units 151 to 154 in layers on the surface of the transfer belt 17 to a transfer region opposed by a secondary transfer roller 18.

[0025] The secondary transfer roller 18 faces the drive roller 171 with the transfer belt 17 sandwiched therebetween. The secondary transfer roller 18 transfers (secondarily transfers) the toner image formed on the transfer belt 17 onto the paper P passing between the secondary transfer roller 18 and itself.

[0026] The fixing device 19 heats and pressurizes the paper P. The fixing device 19 includes a heating roller 191 and a pressure roller 192 that face each other with the transport path of the paper P sandwiched between them. The heating roller 191 includes a heat source such as a heater. The heating roller 191 heated by the heat source comes into contact with the paper P to heat the paper P. The pressure roller 192 pressurizes the paper P that passes between the pressure roller 192 and the heating roller 191. Thus, the fixing device 19 fixes the toner image transferred onto the paper P to the paper P.

[0027] The printer 10 also includes a duplex unit 50 and a paper output tray 60. The duplex unit 50 prepares the paper P so that printing can be performed on the back side. The duplex unit 50 switches the paper P back to turn it over, and sends it to the transfer area between the transfer belt 17 and the secondary transfer roller 18. The paper output tray 60 is for discharging the paper P after printing has been completed.

[0028] The scanner 20 reads an image from a document etc. The scanner 20 includes a reading module 70 and a document feeder 80.

[0029] The reading module 70 applies illumination light to the surface of the document having the image to be read (hereinafter referred to as the document surface), receives the reflected light with an image sensor (not shown) and converts it into a digital signal. In this way, the reading module 70 reads the image from the document surface.

[0030] The document feeder 80 is, for example, an ADF (auto document feeder). The document feeder 80 transports documents placed on a document tray 81 one after another through a document glass 82. The reading module 70 reads an image from the document transported to the document glass 82. The document feeder 80 may be provided with another reading module for reading an image from the back side of the document.

[0031] The operation panel 30 is a man-machine interface that performs input and output between the device 100 and an operator of the device 100. The operation panel 30 includes, for example, a touch panel 31, an input device 32, and the like.

[0032] The touch panel 31 is, for example, a laminate of a display such as a liquid crystal display or an organic EL display and a pointing device that accepts touch input. The display of the touch panel 31 displays a screen for notifying the operator of the device 100 of various information. The touch panel 31 also accepts touch operations by the operator.

[0033] The input device 32 accepts operations by an operator of the apparatus 100. The input device 32 is, for example, a keyboard, a keypad, or a touchpad.

[0034] Fig. 3 is a perspective view of the housing 1 of the device 100 as seen from the left rear, and Fig. 4 is a perspective view showing only the frame 90 with the exterior panel removed from the housing 1 in Fig. 3. Figs. 3 and 4 show the device 100 in Fig. 1 with a paper feed system option device having multiple paper feed cassettes 11 removed.

[0035] 3, the housing 1 has a rear panel 91 at the rear of a frame 90, and side panels 92 (only the left side is shown here) on the left and right sides of the frame 90. The paper output tray 60 is at the same height as the upper ends of the left and right side panels 92. Above the paper output tray 60, there is a space S for discharging paper P on which an image has been formed into the inside of the housing 1 (intra-body paper output).

[0036] As shown in Fig. 4, the frame 90 has a rear frame 93 extending in the up-down and left-right directions at the rear of the device 100. The rear frame 93 is made of sheet metal, and has a substantially rectangular opening 94 for mounting the power supply unit 110, as shown in Fig. 5. Fig. 5 shows the power supply unit 110 with the rear cover 111 (Fig. 8) removed. The opening 94 is located off to the upper left of the rear frame 93. The rear panel 91 (Fig. 3) is attached behind the power supply unit 110 so as to cover the rear side of the rear frame 93.

[0037] The opening 94 of the rear frame 93 is located in a position facing the space S above the paper discharge tray 60. Therefore, as shown in Fig. 6, when the opening 94 of the rear frame 93 is viewed from the space S side above the paper discharge tray 60, the front surface 1101 of the power supply unit 110 appears exposed from the opening 94 toward the space S.

[0038] However, because there is an inner panel 95 (FIGS. 10 and 11) covering the opening 94 at the rear of the space S, i.e., in front of the rear frame 93, the power supply unit 110 cannot actually be seen from the space S side. In other words, the power supply unit 110 is located adjacent to the rear of the space S with the inner panel 95, which functions as a partition wall, in between. The inner panel 95 also has multiple slit-shaped ventilation holes 951 (FIGS. 10 and 11) for ventilation at a position facing the power supply unit 110. The ventilation holes 951 are for cooling the power supply unit 110.

[0039] 7 and 8, the power supply unit 110 includes a cooling duct 112. The cooling duct 112 has an exhaust port 1121 that communicates with the internal space of a case 113 of the power supply unit 110, and an intake port 1122 that opens toward the rear of the rear frame 93. A blower fan (not shown) is located inside the cooling duct 112. The intake port 1122 of the cooling duct 112 is located opposite a plurality of slit-shaped ventilation holes 911 (FIG. 3) in the rear panel 91. The case 113 of the power supply unit 110 has an exhaust port 1131 that is widely open on the left end face opposite the exhaust port 1121 of the cooling duct 112.

[0040] The power supply unit 110 accommodates and disposes a power supply circuit board 114 shown in FIG. 9 in a case 113. The power supply circuit board 114 is formed by mounting a plurality of electronic components, including two transformers 1151 and 1152, three choke coils 1153, 1154, and 1155, a capacitor 1156, and two heat sinks 1157 and 1158, on a board 1159. Of the plurality of electronic components mounted on the board 1159, the electronic components that become the hottest are the transformer 1151 and the heat sink 1157. That is, when the power supply unit 110 is attached to the opening 94 of the rear frame 93, the power supply circuit board 114 becomes hottest near the upper right.

[0041] When the blower fan of cooling duct 112 is rotated, outside air flows into case 113 of power supply unit 110 through vent hole 911 of rear panel 91 and intake port 1122 of cooling duct 112, and is exhausted through exhaust port 1131 of case 113. Hot air flows between multiple electronic components of power supply circuit board 114 and is exhausted from exhaust port 1131, and can be released to the outside of device 100 through multiple vent holes 951 leading to space S and gaps in housing 1, as shown by arrows in FIG.

[0042] 11, the multiple ventilation holes 951 provided in the inner panel 95 are positioned off to the upper left when viewed from the space S side. This position faces the power supply unit 110 (outlined by a dashed line in FIG. 11) located behind the inner panel 95. By providing the multiple ventilation holes 951 in this position, the ventilation holes 951 are less likely to overlap with the paper P discharged onto the paper output tray 60 (the portion where multiple sheets of paper P are stacked is shown by diagonal lines in FIG. 11), and hot air can be effectively exhausted into the space S through the ventilation holes 951.

[0043] According to this embodiment, the power supply unit 110, which serves as a heat generating source, is disposed adjacent to the space S for discharging the printed paper P into the body, and multiple ventilation holes 951 are provided in the inner panel 95 between the power supply unit 110 and the space S at a position facing the power supply unit 110, so that the heat of the power supply unit 110 can be effectively dissipated through the space S which is free of members such as the toner cartridges 141-144 that are easily adversely affected by heat. Therefore, according to this embodiment, the toner contained in the toner cartridges 141-144 is not heated, and problems such as the toner melting or sticking due to heat do not occur.

[0044] Other effects of this embodiment will be described below with reference to FIGS. 7, 8, and 12 to 15. The power supply unit 110 is placed in the opening 94 of the rear frame 93 as shown in Fig. 7, and is fastened to the rear frame 93 using three screws 116, 117, and 118 as shown in Fig. 8. The power supply unit 110 is attached to the rear frame 93 by fastening a part of the upper end of the case 113 to the rear frame 93 with the screw 116, fastening a part of the right end of the case 113 to the rear frame 93 with the screw 117, and fastening a part of the lower end of the case 113 to the rear frame 93 with the screw 118.

[0045] In this manner, by fixing and integrating the power supply unit 110 to the rear frame 93 so that the opening 94 provided in the rear frame 93 is blocked by the power supply unit 110, the case 113 of the power supply unit 110 can be made part of the rear frame 93, thereby increasing the mechanical strength of the rear frame 93. Also, by fixing the periphery of the case 113 of the power supply unit 110 in contact with the rear frame 93 made of sheet metal, the heat dissipation effect of the power supply unit 110 can be improved.

[0046] As shown in FIG. 12, the rear frame 93 includes a drive mechanism such as a motor and a clutch, and a board unit 96 in addition to the power supply unit 110. As shown in FIG. 13, the board unit 96 is configured by arranging two control boards 961 and 962 side by side and mounting them on a board case 963. The control boards 961 and 962 are, for example, a logic board and a system board. The logic board mainly performs control based on an application program using firmware and logic circuits. The system board mainly performs communication and print jobs. The two control boards 961 and 962 receive power from the power supply circuit board 114.

[0047] After the power supply unit 110 is attached to the opening 94 of the rear frame 93, the board unit 96 is attached to the rear frame 93 so as to cover the rear side of the power supply unit 110. The board unit 96 is attached by fixing a board case 963 to the rear frame 93. For this reason, in FIG. 12, the power supply unit 110 is hidden by the board unit 96 and cannot be seen. As shown in FIG. 14, the power supply unit 110 and the board unit 96 are arranged one above the other and fixed to the rear frame 93, thereby further increasing the mechanical strength of the rear frame 93.

[0048] Furthermore, by mounting the power supply unit 110 in the opening 94 of the rear frame 93 and arranging the board unit 96 on the rear side of the power supply unit 110, the relatively heavy power supply unit 110 can be mounted closer to the front of the device 100. Therefore, as shown in Fig. 15, the power supply unit 110 can be arranged slightly closer to the front than the rear side of the housing 1 of the device 100, and the degree to which the center of gravity of the device 100 is biased toward the rear side can be suppressed. This reduces the difference in weight between both hands when an operator lifts the device 100 by holding the two handles provided on the side panels 92 of the housing 1, and improves the left and right weight balance somewhat.

[0049] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the invention. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The detailed embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0050] Other embodiments will be described below. 1. Of the heat-generating electronic components, the one that becomes the hottest is located adjacent to an open space. 2. The electronic component that gets the hottest is the transformer. 3. The power supply unit is equipped with a cooling duct. 4. The cooling duct intake is connected to the intake hole on the back of the housing. 5. The exhaust port of the cooling duct is connected to the inside of the power supply unit case. [Explanation of symbols]

[0051] 1...housing, 141, 142, 143, 144...toner cartridge, 60...output tray, 90...frame, 91...rear panel, 911...ventilation hole, 93...rear frame, 94...opening, 95...inner panel, 951...ventilation hole, 100...image forming apparatus, 110...power supply unit, 112...cooling duct, 113...case, 114...power supply circuit board, 1151...transformer, 1157...heat sink, P...paper, S...space.

Claims

1. A housing having a space for internal paper discharge; a power supply unit provided in the housing adjacent to the space; An image forming apparatus comprising:

2. the power supply unit includes a heat-generating electronic component, the heat-generating electronic component being located adjacent to the space; The image forming apparatus according to claim 1 .

3. the housing has a partition wall on the power supply unit side of the space, The partition has an air hole at a position facing the power supply unit, the air hole penetrating from the space to the power supply unit side. The image forming apparatus according to claim 2 .

4. a paper output tray for stacking the paper sheets outputted to the space; the partition has the vent hole at a position that does not face the sheets stacked on the paper discharge tray; The image forming apparatus according to claim 3 .

5. a board unit provided in the housing on the opposite side of the power supply unit from the space; The image forming apparatus according to claim 1 .

Images