Developing device and image forming apparatus

Abstract

The invention discloses a developing device and an image forming apparatus, the developing device includes: a housing accommodating a developer; a developer holding unit that is disposed in an opening of the housing facing an image holding body, and that holds the developer and rotates; an exhaust passage for discharging air in the housing to the outside; and a suction passage that sucks the developer leaked to the outside from an opening of the frame, the exhaust passage and the suction passage being disposed at different positions along an axial direction of the developer holding unit.

Description

Technical Field

[0001] The present invention relates to a developing device and an image forming device. Background Art

[0002] Conventionally, as technologies related to the developing device, for example, technologies disclosed in the following three patent documents and the like have been proposed.

[0003] Japanese Patent Gazette No. 2018-049118 discloses a developing device, which is composed of: a developer accommodating container that accommodates the developer; a developer retaining body that is arranged at an opening of the developer accommodating container in a manner opposite to and rotating from the developer retaining body, and retains the developer; an exhaust passage that discharges the air in the developer accommodating container to the outside; a capturing member that captures the colorant in the exhaust gas passing through the exhaust passage; and a closing member, a base end of which is retained in the developer accommodating container, and a front end of which is clamped by the developer accommodating container and the developer retained in the developer retaining body on the downstream side of the opening along the rotation direction of the developer retaining body to close the gap.

[0004] Japanese Patent Application Laid-Open No. 08-220882 discloses a developing device having a suction unit having an air vent formed along a bottom wall of a developing tank accommodating a developer carrier, and sucking air from a duct formed in the air vent through a toner filter.

[0005] Japanese Patent Publication No. 2013-125148 discloses an image forming device, which is configured to include: a duct, which is arranged above a developing device and connected to an air outflow path; an exhaust unit, which generates an air flow in the duct; and a filter, which is arranged on the air flow discharge side of the duct and captures colorant that passes through the duct together with the air in the developing container. Summary of the invention

[0006] An object of the present invention is to achieve both exhaust of air and suction of scattered toner in the developing device while avoiding enlargement of the developing device compared to a case where the exhaust passage and the suction passage are all arranged at the same position along the axial direction of the developer holding unit.

[0007] According to a first aspect of the present invention, a developing device is provided, comprising: a frame that accommodates a developer; a developer holding unit that is arranged at an opening portion of the frame that is opposite to an image holding body, holds the developer and rotates; an exhaust channel that discharges air in the frame to the outside; and a suction channel that sucks the developer leaked from the opening portion of the frame to the outside, wherein the exhaust channel and the suction channel are arranged to have different positions along the axial direction of the developer holding unit.

[0008] According to a second aspect of the present invention, in the developing device according to the first aspect, the suction passage is arranged on a downstream side of an opening portion of the frame in a rotation direction of the developer holding unit.

[0009] According to a third aspect of the present invention, in the developing device according to the first aspect, the exhaust duct is arranged at an upper portion of the frame along a vertical direction.

[0010] According to a fourth aspect of the present invention, in the developing device based on the third aspect, the exhaust passage is arranged on the downstream side of the opening portion of the frame along the rotation direction of the developer holding unit and at the same position as the suction passage when viewed from the rotation axis direction of the developer holding unit.

[0011] According to a fifth aspect of the present invention, in the developing device according to the first aspect, the suction passage is arranged at least at both end portions along the axial direction of the developer holding unit.

[0012] According to a sixth aspect of the present invention, in the developing device according to the fifth aspect, the suction passage is further arranged between the suction passages arranged at both end portions along the axial direction of the developer holding unit.

[0013] According to a seventh aspect of the present invention, in the developing device according to the sixth aspect, the suction passages are respectively arranged at positions divided equally into N portions along the axial direction of the developer holding unit, where N is an integer greater than or equal to 2.

[0014] According to an eighth aspect of the present invention, in the developing device according to the fifth aspect, the exhaust passage is arranged at a position other than the suction passage along the axial direction of the developer holding unit.

[0015] According to a ninth aspect of the present invention, in the developing device according to the first aspect, the exhaust passage includes, at an outlet portion thereof, a catching unit for catching the developer leaking from the exhaust passage to the outside.

[0016] According to a tenth aspect of the present invention, in the developing device according to the ninth aspect, the capture unit is provided on all of the exhaust passages.

[0017] According to an eleventh aspect of the present invention, in the developing device according to the ninth aspect, the capture unit is provided outside the exhaust passage adjacent to the suction passage.

[0018] According to a twelfth aspect of the present invention, in the developing device according to the first aspect, a portion of the exhaust passage along the axial direction of the developer holding unit is blocked, and the blocked exhaust passage communicates with the suction passage.

[0019] According to the thirteenth aspect of the present invention, in the developing device based on the twelfth aspect, the suction channel is arranged at multiple locations including the two end portions and the central portion along the axial direction of the developer holding unit, and as for the exhaust channel, the exhaust channel adjacent to the suction channel arranged at a position other than the two end portions and the central portion along the axial direction of the developer holding unit is blocked.

[0020] According to the fourteenth aspect of the present invention, there is provided an image forming device, which comprises: an image holding unit which holds an electrostatic latent image; and a developing unit which develops the electrostatic latent image of the image holding unit, and a developing device according to any one of the first to thirteenth aspects is used as the developing unit.

[0021] (Effect)

[0022] According to the first aspect, compared with the case where the exhaust passage and the suction passage are arranged at the same position along the axial direction of the developer holding unit, it is possible to avoid increasing the size of the developing device while achieving both exhaust of air in the developing device and suction of scattered toner.

[0023] According to the second aspect, compared with a case where the suction passage is arranged on the upstream side of the opening of the frame in the rotation direction of the developer holding unit, the developer discharged with the rotation of the developer holding unit can be effectively sucked.

[0024] According to the third aspect, compared with a case where the exhaust duct is arranged at the lower portion of the housing along the vertical direction, the air in the housing can be exhausted to the outside without interfering with the developer in the housing.

[0025] According to the fourth aspect, compared with a case where the position of the exhaust passage in the rotation direction of the developer holding unit is different from that of the suction passage, it is possible to avoid an increase in the size of the developing device.

[0026] According to the fifth aspect, compared with a case where the suction passage is not arranged at both end portions along the axial direction of the developer holding unit, the developer leaked from the opening to the outside can be effectively sucked.

[0027] According to the sixth aspect, compared with a case where the suction passages are arranged only at both ends of the developer holding unit in the axial direction, it is easier to suck the developer leaked from the middle position in the axial direction of the developer holding unit.

[0028] According to the seventh aspect, compared with a case where the suction passages are unevenly arranged in the axial direction of the developer holding unit, the developer leaked from the opening to the outside can be uniformly sucked.

[0029] According to the eighth aspect, compared with a case where a part or all of the exhaust passage overlaps with the position of the suction passage along the axial direction of the developer holding unit, it is possible to avoid an increase in the size of the developing device.

[0030] According to the ninth aspect, compared with a case where the exhaust duct is not provided with a capture unit for capturing the developer leaking from the exhaust duct to the outside at the outlet portion thereof, leakage of the developer from the exhaust duct can be suppressed.

[0031] According to the tenth aspect, compared with a case where the capture unit is provided in a part of the exhaust passage, it is possible to reduce the developer leaking from the exhaust passage.

[0032] According to the eleventh aspect, compared with a case where the trap unit is provided in all the exhaust passages, it is possible to suppress a reduction in the exhaust effect due to clogging of the developer in the trap unit.

[0033] According to the twelfth aspect, compared with the case where only the exhaust passage is blocked, the exhaust effect of the exhaust passage can be maintained.

[0034] According to the thirteenth aspect, compared with the case where the exhaust passage is blocked regardless of the position with respect to the suction passage, it is possible to achieve a better balance between exhausting the air in the developing device and suctioning the scattered toner.

[0035] According to the fourteenth aspect, compared with a case where the developing device according to any one of the first to thirteenth aspects is not used as a developing unit, it is possible to achieve both exhaust of air in the developing device and suction of scattered toner. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a diagram showing the overall structure of an image forming apparatus to which a developing device according to Embodiment 1 of the present invention is applied;

[0037] Figure 2 is a structural diagram showing an image forming unit of an image forming apparatus to which a developing device according to Embodiment 1 of the present invention is applied;

[0038] Figure 3 is a longitudinal sectional structural diagram showing a developing device according to Embodiment 1 of the present invention;

[0039] Figure 4 is a rear structural diagram showing a developing device according to Embodiment 1 of the present invention;

[0040] Figure 5 is a longitudinal sectional structural diagram showing a developing device according to Embodiment 1 of the present invention;

[0041] Figure 6is a rear structural view showing a state where a channel forming member is removed from the developing device according to the first embodiment of the present invention;

[0042] Figure 7 is a perspective structural diagram showing a main part of a developing device according to Embodiment 1 of the present invention;

[0043] Figure 8 is a three-dimensional structural diagram showing the configuration of the developing device and the suction duct;

[0044] Fig. 9 is an explanatory diagram showing the operation of the developing device according to the first embodiment of the present invention;

[0045] Fig.10 is an explanatory diagram showing the operation of the developing device according to the first embodiment of the present invention;

[0046] Fig.11 is a perspective structural diagram showing a main part of a developing device according to a second embodiment of the present invention;

[0047] Fig.12 is a perspective structural diagram showing a main part of a developing device according to a third embodiment of the present invention;

[0048] Fig.13 It is a rear structural view showing a state where a passage forming member is removed from a developing device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0049] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described with reference to the drawings.

[0050] [Implementation method 1]

[0051] Figure 1 and Figure 2 An image forming apparatus to which the developing device according to Embodiment 1 is applied is shown. Figure 1 shows the overall outline of the image forming apparatus, Figure 2 The main parts of the image forming apparatus (such as the image generating device) are shown in an enlarged manner. Figure 1 In the figure, symbol X indicates the horizontal direction (width direction) of the image forming apparatus, symbol Y indicates the depth direction of the image forming apparatus, and symbol Z indicates the vertical direction of the image forming apparatus.

[0052] <Overall Structure of Image Forming Apparatus>

[0053] The image forming apparatus 1 according to the first embodiment is configured as, for example, a color printer. Figure 1As shown, the image forming apparatus 1 includes, inside the apparatus body 1a, a plurality of image forming apparatuses 10 that form toner images developed by toner constituting the developer 4; an intermediate transfer apparatus 20 that holds the toner images formed by the respective image forming apparatuses 10 and finally conveys them to a secondary transfer position for secondary transfer to a recording paper 5 as an example of a recording medium; a paper feeder 50 that holds and conveys the required recording paper 5 to be supplied to the secondary transfer position of the intermediate transfer apparatus 20; and a fixing apparatus 40 that fixes the toner images on the recording paper 5 that have been secondary transferred by the intermediate transfer apparatus 20. In addition, the apparatus body 1a of the image forming apparatus 1 is formed by a supporting structural member, an exterior cover, and the like.

[0054] The image generating device 10 is composed of four image generating devices 10Y, 10M, 10C, and 10K that are specialized in forming toner images of four colors, namely yellow (Y), magenta (M), cyan (C), and black (K). These four image generating devices 10 (Y, M, C, K) are arranged in a row in an inclined state in the internal space of the device body 1a. Of the four image generating devices 10 (Y, M, C, K), the image generating device 10Y for yellow (Y) is located at an upper position along the vertical direction Z and is relatively high, and the image generating device 10K for black (K) is located at a relatively low position.

[0055] like Figure 1 and Figure 2 As shown, each image generating device 10 (Y, M, C, K) of yellow (Y), magenta (M), cyan (C) and black (K) has a rotating photosensitive drum 11 as an example of an image holding unit for holding an electrostatic latent image, and each device as an example of the following colorant image forming unit is mainly arranged around the photosensitive drum 11. The main devices include: a charging device 12 for charging the image-forming peripheral surface (image holding surface) of the photosensitive drum 11 to a desired potential, an exposure device 13 for irradiating the charged peripheral surface of the photosensitive drum 11 with light based on image information (signal) to form an electrostatic latent image for each color with a potential difference, a developing device 14 as an example of a developing unit for developing the electrostatic latent image with a colorant of a developer 4 of a corresponding color (Y, M, C, K) to form a colorant image, a primary transfer device 15 for transferring each colorant image to an intermediate transfer device 20, and a drum cleaning device 16 for eliminating and cleaning attachments such as the colorant remaining on the image holding surface of the photosensitive drum 11 after the primary transfer.

[0056] The photosensitive drum 11 has an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material formed on the circumference of a grounded cylindrical or columnar substrate. The photosensitive drum 11 is supported to rotate in the direction indicated by arrow A by power transmitted from a driving device (not shown).

[0057] like Figure 2 As shown, the charging device 12 includes a contact type charging roller 121 arranged in contact with the photosensitive drum 11. On the back of the charging roller 121, a cleaning roller 122 is arranged to clean the surface of the charging roller 121. A charging voltage is supplied to the charging roller 121 of the charging device 12. As the charging voltage, a voltage or current having the same polarity as the charged polarity of the toner supplied from the developing device 14 is supplied when the developing device 14 performs reverse development. In addition, as the charging device 12, a non-contact type charging device such as a scorotron arranged on the surface of the photosensitive drum 11 in a non-contact state can also be used.

[0058] The exposure device 13 irradiates the peripheral surface of the charged photosensitive drum 11 with light according to the image information input to the image forming device 1 to form an electrostatic latent image. When forming the latent image, the image information (signal) input to the image forming device 1 by any method is sent to the exposure device 13.

[0059] The exposure device 13 is composed of an LED print head, which forms an electrostatic latent image by irradiating light corresponding to image information to the photosensitive drum 11 using a plurality of LEDs (Light Emitting Diodes) arranged along the axial direction of the photosensitive drum 11 as light emitting elements. Alternatively, as the exposure device 13, a device that deflects and scans laser light formed according to image information along the axial direction of the photosensitive drum 11 may be used.

[0060] The developing device 14 is composed of a developing roller 141 that holds the developer 4 and conveys it to the developing area facing the photosensitive drum 11, a stirring and supplying member 142 composed of a screw conveyor and the like that supplies the developer while stirring the developer 4 and passing it through the developing roller 141, a stirring and conveying member 143 composed of a screw conveyor and the like that conveys the developer 4 to the stirring and supplying member 142 while stirring the developer 4, and a layer thickness limiting member 144 that limits the amount (layer thickness) of the developer held by the developing roller 141. In the developing device 14, a voltage for development is supplied between the developing roller 141 and the photosensitive drum 11 from a power supply device (not shown). As the developer 4 of each color, for example, a two-component developer containing a non-magnetic toner and a carrier is used. In addition, the structure of the developing device 14 will be described in detail later.

[0061] The primary transfer device 15 is a contact type transfer device having a primary transfer roller, which rotates while in contact with the periphery of the photosensitive drum 11 via the intermediate transfer belt 21 and is supplied with a primary transfer voltage. As the primary transfer voltage, a DC voltage having a polarity opposite to the charged polarity of the toner is supplied from a power supply device (not shown).

[0062] like Figure 2 As shown in the figure, the drum cleaning device 16 is composed of a container-shaped main body 16a with a part of the container opened, a cleaning plate 16b configured to contact the peripheral surface of the photosensitive drum 11 after the primary transfer with a required pressure to remove and clean the residual toner and other attached materials, and a delivery member 16c such as an auger that recovers the toner and other attached materials removed by the cleaning plate 16b and delivers them to a recovery system not shown in the figure. As the cleaning plate 16b, a plate-shaped member (such as a scraper) made of a material such as rubber is used.

[0063] like Figure 1 As shown in FIG. 1 , the intermediate transfer device 20 is arranged to be located above each image generating device 10 (Y, M, C, K) along the vertical direction Z. Figure 2 As shown, the intermediate transfer device 20 is mainly composed of the following devices: an intermediate transfer belt 21 that rotates in the direction indicated by the arrow B while passing through the primary transfer position between the photosensitive drum 11 and the primary transfer device 15, a plurality of belt support rollers 22 to 25 that maintain the intermediate transfer belt 21 in a desired state from its inner surface and support it in a rotatable manner, a secondary transfer device 30 that is arranged on the outer peripheral surface (image holding surface) side of the intermediate transfer belt 21 supported by the belt support roller 25 and transfers the colorant image on the intermediate transfer belt 21 to the recording paper 5 for the second time, and a belt cleaning device 26 that eliminates and cleans the colorant, paper powder and other attachments that remain attached to the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30.

[0064] In the first embodiment, as described above, the intermediate transfer device 20 is arranged to be located above each image generating device 10 (Y, M, C, K) along the vertical direction Z. Figure 2 As shown, since the developing device 14 arranged on the periphery of the photosensitive drum 11 transfers the colorant image developed on the photosensitive drum to the intermediate transfer belt 21 of the intermediate transfer device 20 located at an upper position along the vertical direction Z, it is difficult to form a gap between the upper part of the developing device 14 and the intermediate transfer belt 21, and the upper end of the developing device 14 must be arranged at a position close to the intermediate transfer belt 21.

[0065] As the intermediate transfer belt 21, for example, an endless belt made of a material in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as a polyimide resin or a polyamide resin is used. In addition, the belt support roller 22 is configured as a driving roller that is rotationally driven by a driving device (not shown) and a support roller of the belt cleaning device 26, the belt support roller 23 is configured as a surface exposure roller that maintains the stroke position of the intermediate transfer belt 21, the belt support roller 24 is configured as a tension applying roller that applies tension to the intermediate transfer belt 21, and the belt support roller 25 is configured as a backup roller for secondary transfer.

[0066] like Figure 1 As shown in FIG. 1 , the secondary transfer device 30 is a contact type transfer device including a secondary transfer roller 31, which rotates in contact with the circumference of the intermediate transfer belt 21 at a secondary transfer position which is an outer circumference of the intermediate transfer belt 21 supported by the belt support roller 25 in the intermediate transfer device 20, and is supplied with a secondary transfer voltage. In addition, a direct current voltage having a polarity opposite to or the same polarity as the charged polarity of the toner is supplied to the secondary transfer roller 31 or the belt support roller 25 of the intermediate transfer device 20 as the secondary transfer voltage.

[0067] The belt cleaning device 26 is composed of a main body 260, a cleaning plate 261, a delivery member 262, etc. The main body 260 is a container-like shape with a part opened, the cleaning plate 261 is configured to contact the peripheral surface of the intermediate transfer belt 21 after the secondary transfer with a required pressure to eliminate and clean the residual toner and other attached materials, and the delivery member 262 is a screw conveyor or the like that recovers the toner and other attached materials eliminated by the cleaning plate 261 and delivers it to a recovery system not shown. As the cleaning plate 261, a plate-like member (such as a scraper) made of a material such as rubber is used.

[0068] like Figure 1 As shown in FIG. 1 , the fixing device 40 is configured by arranging a heating rotating body 41 in the form of a roller or a belt which is heated by a heating unit so that the surface temperature is maintained at a desired temperature, and a pressing rotating body 42 in the form of a roller or a belt which is contacted and rotated under a predetermined pressure in a state substantially along the axial direction of the heating rotating body 41. In the fixing device 40, the contact portion where the heating rotating body 41 and the pressing rotating body 42 are in contact becomes a fixing processing portion which performs the desired fixing process (heating and pressing). In addition, an exit roller 43 which conveys the recording paper 50 which has been subjected to the fixing process by the fixing device 40 is arranged at the exit portion of the fixing device 40.

[0069] The paper feed device 50 is disposed at a position below the image generating devices 10 (Y, M, C, K) of yellow (Y), magenta (M), cyan (C), and black (K). The paper feed device 50 is mainly composed of a single (or a plurality of) paper containers 51 that contain recording paper 5 of a desired size, type, etc., and feeding devices 52 and 53 that feed the recording paper 5 one by one from the paper container 51. The paper container 51 is installed to be drawn out, for example, to the front side (the side facing the user during operation) of the device body 1a, or to the right side along the width direction X in the example shown in the figure.

[0070] Examples of the recording paper 5 include ordinary paper, thin paper, and OHP sheets used in electrophotographic copiers and printers. In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper 5 is preferably as smooth as possible. For example, coated paper obtained by coating the surface of ordinary paper with a resin or the like, and so-called thick paper with a relatively large basis weight such as coated paper for printing may be used.

[0071] like Figure 1 As shown, a paper feed conveying path 55 is provided between the paper feed device 50 and the secondary transfer device 30, and the paper feed conveying path 55 is composed of a single (or multiple) paper conveying roller pair 54 or a conveying guide member (not shown) for conveying the recording paper 5 fed from the paper feed device 50 to the secondary transfer position. The paper conveying roller pair 54 arranged in front of the secondary transfer device 30 is configured as, for example, a registration roller for adjusting the conveying timing of the recording paper 5. In addition, a paper discharge conveying path 58 is provided at the upper part of the fixing device 40 along the vertical direction Z, and the paper discharge conveying path 58 includes a paper discharge roller pair 57 for discharging the fixed recording paper 5 fed from the outlet roller 36 of the fixing device 40 to a discharge tray 56 provided at the upper part of the device body 1a.

[0072] In addition, a double-sided transport path 60 having a plurality of double-sided transport roller pairs 59 is provided inside the device body 1a. While the rear end of the recording paper 5 having an image formed on one side is held by the paper discharge roller pair 57, the double-sided transport roller pair 59 switches the rotation direction of the paper discharge roller pair 57 from the forward direction (discharge direction) to the reverse direction, thereby flipping the front and back sides of the recording paper 5 and transporting it again to the paper transport roller pair 54.

[0073] Figure 1 In the figure, symbol 61 indicates a manual tray which is openably and closably arranged on the side (the left side in the figure) of the device body 1a of the image forming device 1, and a manual paper feed conveying path 64 is arranged between the manual tray 61 and the paper conveying roller pair 54. The manual paper feed conveying path 64 is composed of a feeding device 62 for feeding out the recording paper 5 accommodated in the manual tray 61 one by one, a paper conveying roller pair 63, and a conveying guide member not shown in the figure.

[0074] in addition, Figure 1 The symbols 145 (Y, M, C, K) in the drawing respectively denote a plurality of toner boxes arranged in a direction perpendicular to the paper surface and containing developers containing at least toner to be supplied to the corresponding developing devices 14 (Y, M, C, K).

[0075] in addition, Figure 1 Reference numeral 100 in the figure denotes a control device that generally controls the operation of the image forming apparatus 1. The control device 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), or a bus or a communication interface that connects the CPU and ROM, etc. (not shown).

[0076] <Operation of Image Forming Apparatus>

[0077] Next, a basic image forming operation by the image forming apparatus 1 will be described.

[0078] Here, an operation of forming a full-color image composed of a combination of toner images of four colors (Y, M, C, K) using the above-mentioned four image generating devices 10 (Y, M, C, K) will be described.

[0079] Regarding the image forming apparatus 1, when the control device 100 receives instruction information requesting an image forming action (printing), the four image generating devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, etc. are started.

[0080] In each image forming device 10 (Y, M, C, K), first, each photosensitive drum 11 rotates in the direction indicated by arrow A, and each charging device 12 charges the surface of each photosensitive drum 11 to a desired polarity (negative polarity in Embodiment 1) and potential. Next, the exposure device 13 irradiates the surface of the charged photosensitive drum 11 with light based on a signal of an image obtained by converting the information of the image input to the image forming device 1 into each color component (Y, M, C, K), and forms an electrostatic latent image of each color component with a desired potential difference on the surface.

[0081] Next, each image generating device 10 (Y, M, C, K) supplies the toner of the corresponding color (Y, M, C, K) charged to the required polarity (negative polarity) from the developing roller 141 to the electrostatic latent image of each color component formed on the photosensitive drum 11 and electrostatically adheres it to perform development. Through this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a toner image of four colors (Y, M, C, K) developed by the toner of the corresponding color.

[0082] Next, when the colorant images of each color formed on the photosensitive drum 11 of each image generating device 10 (Y, M, C, K) are transmitted to the primary transfer position, the primary transfer device 15 (Y, M, C, K) transfers the colorant images of each color once in a sequentially overlapping state relative to the intermediate transfer belt 21 of the intermediate transfer device 20 that rotates in the direction indicated by the arrow B.

[0083] In each image generating device 10 (Y, M, C, K) that has completed primary transfer, the drum cleaning device 16 removes the attached matter by scraping to clean the surface of the photosensitive drum 11. Thus, each image generating device 10 (Y, M, C, K) is ready to perform the next image generating operation.

[0084] Next, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and transported to the secondary transfer position. On the other hand, in the paper feeding device 50, the required recording paper 5 is fed to the paper feeding and transporting path 56 in accordance with the image generation operation. In the paper feeding and transporting path 55, the paper feeding roller pair 54 as a registration roller feeds the recording paper 5 in accordance with the transfer timing and supplies it to the secondary transfer position.

[0085] At the secondary transfer position, the secondary transfer roller 31 of the secondary transfer device 30 secondary transfers the toner image on the intermediate transfer belt 21 to the recording paper 5. In addition, in the intermediate transfer device 20 after the secondary transfer is completed, the belt cleaning device 26 removes and cleans the toner and other attached materials remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

[0086] Next, the recording paper 5 to which the toner image is secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roller 31 and then conveyed to the fixing device 40. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced into the contact portion between the rotating heating rotating body 41 and the pressing rotating body 42 and passed through, thereby performing necessary fixing processing (heating and pressing) to fix the unfixed toner image on the recording paper 5. Finally, the recording paper 5 after the fixing is completed is discharged to the discharge tray 56 provided on the upper part of the device body 1a by the paper discharge roller pair 57 when the image forming operation of forming the image only on one side is performed.

[0087] When an image is formed on both sides of the recording paper 5, the recording paper 5 with an image formed on one side is not discharged to the discharge tray 56 by the paper discharge roller pair 57, but the rotation direction of the paper discharge roller pair 57 is switched to the reverse direction while the paper discharge roller pair 57 holds the rear end of the recording paper 5. The recording paper 5 transported in the reverse direction by the paper discharge roller pair 57 is transported to the double-sided transport path 60 including the double-sided transport roller pair 59 and the like, and is transported again to the paper transport roller pair 54 in a reversed state. The paper transport roller pair 54 feeds the recording paper 5 to the secondary transfer position in accordance with the transfer timing, forms an image on the back side of the recording paper 5, and discharges the recording paper 5 with the image fixed on the back side to the discharge tray 56 provided at the upper part of the apparatus main body 1a by the paper discharge roller pair 57.

[0088] Through the above-described operation, a recording paper 5 having a full-color image formed by combining four-color toner images on one or both sides thereof is output.

[0089] <Structure of the developing device>

[0090] Figure 3 and Figure 4 This is a diagram showing a developing device according to Embodiment 1 that is applied to the image forming apparatus configured as described above. Figure 3 This is a longitudinal sectional structural diagram showing the developing device together with the photosensitive drum, etc. Figure 4 This is a rear structural view showing the shape of the developing device as viewed from the side opposite to the photosensitive drum.

[0091] like Figure 3 As shown, the developing device 14 includes a device housing 140 as an example of a frame. The device housing 140 generally includes a lower housing 140a disposed at the lower portion of the developing device 14 along the vertical direction Z, and an upper housing 140b disposed at the upper portion of the developing device 14 along the vertical direction Z. The lower housing 140a and the upper housing 140b are airtightly joined, and a developer accommodating chamber 150 for accommodating the two-component developer 4 is formed inside the device housing 140.

[0092] In the developing device 14 involved in this embodiment 1, the upper housing 140b is not integrally formed, but is divided into an upper housing body 140b' that covers the entire upper part of the developing device 14 and a channel forming member 140b" that covers the upper end surface of the upper housing body 140b' and forms exhaust channels 163, 163... and suction channels 167, 167... in the interior of the upper housing body 140b' as described later.

[0093] An opening 151 is provided in the region of the device housing 140 that faces the photosensitive drum 11. Inside the device housing 140, a developing roller 141 as an example of a developer holding unit that holds the developer 4 and rotates is rotatably arranged in the arrow direction C in a manner that a portion of it is exposed in the opening 151. The developing roller 141 has a magnet roller 141a as an example of a magnetic field generating unit and a cylindrical developing sleeve 141b as an example of a developer conveying unit. The magnet roller 141a is fixedly arranged inside and has a plurality of magnetic poles of required polarity arranged at required positions along the circumferential direction. The developing sleeve 141b is arranged on the outer periphery of the magnet roller 141a so as to be rotatable at a required rotation speed along the arrow direction C. The developing sleeve 141b is formed into a cylindrical shape by a non-magnetic material such as aluminum or non-magnetic stainless steel. The developing sleeve 141b is rotationally driven by transmitting a driving force from the device body 1a.

[0094] In the developing device 14 according to the first embodiment, the rotation direction C of the developing sleeve 141b is set to be opposite to the rotation direction A of the photosensitive drum 11. Figure 3 As shown, the rotation direction A of the photosensitive drum 11 is set to the counterclockwise direction, and the rotation direction C of the developing sleeve 141b is set to the clockwise direction. As a result, the outer peripheral surface of the developing sleeve 141b moves in the same direction as the movement direction of the photosensitive drum 11 surface in the developing area facing the photosensitive drum 11.

[0095] The rotation speed of the developing sleeve 141b is determined based on the productivity of the image forming apparatus 1 determined by the rotation speed (process speed) of the photosensitive drum 11. The productivity of the image forming apparatus 1 is expressed, for example, by the number of A4-size (LEF) recording paper 5 that can form an image per unit time. The rotation speed (peripheral speed) of the developing sleeve 141b becomes higher as the productivity of the image forming apparatus 1 increases.

[0096] Inside the device housing 140, a stirring and supplying member 142 is arranged obliquely below the developing roller 141 in the vertical direction. The stirring and supplying member 142 is composed of an auger (supply auger) or the like that draws up the developer 4 contained in the developer containing chamber 150 and supplies it to the developing roller 141. The stirring and supplying member 142 is driven to rotate in a desired direction by the rotational driving force transmitted from the developing roller 141. In addition, inside the device housing 140, a stirring and conveying member 143 is arranged obliquely below the stirring and supplying member 142. The stirring and conveying member 143 is composed of an auger (mixing auger) or the like that conveys the developer 4 supplied to the inside of the device housing 140 while stirring it. The stirring and conveying member 143 is driven to rotate in a desired direction by the driving force transmitted from the stirring and supplying member 142 or the like.

[0097] The lower housing 140a is provided with a first accommodating portion 147 and a second accommodating portion 148 having a substantially semi-cylindrical cross section in order to accommodate the stirring and supplying member 142 and the stirring and conveying member 143. The first accommodating portion 147 and the second accommodating portion 148 are separated by a partition wall 152 provided on the lower housing 140a. The space above the first accommodating portion 147 becomes a developer accommodating chamber 150. In addition, the upper housing body 140b' is provided with a third accommodating portion 153, which is formed as a part of a substantially cylindrical cross section that forms a conveying passage for the developer 4 together with the second accommodating portion 148 of the lower housing 140a.

[0098] In addition, at both ends of the partition wall 152 along the longitudinal direction, first and second passages (not shown) are provided for transferring the developer 4 between the stirring and supplying member 142 and the stirring and conveying member 143. Figure 4 As shown, the end of the inner side of the stirring and conveying member 143 along the axial direction is extended so as to protrude from the back side of the device housing 140. A substantially cylindrical supply portion 154 with a closed end is provided at the extended portion of the stirring and conveying member 143. A supply port 155 for supplying the developer 4 of the corresponding color from the toner box 145 (Y, M, C, K) is opened in the substantially cylindrical supply portion 154. In addition, the supply port 155 is covered by a switch member (not shown) in an openable and closable manner.

[0099] Figure 4 In the figure, reference numeral 156 denotes a coupling portion for transmitting a rotational driving force from the apparatus body 1 a side to the developing roller 141 .

[0100] The developing device 14 configured as described above is in a trend of increasing the rotation speed of the developing roller 141 in order to meet the improvement in productivity required by the image forming apparatus 1. When the rotation speed of the developing roller 141 is increased in the developing device 14, as shown in FIG. Figure 3 As shown, as the developing roller 141 rotates, the amount of air taken into the inside of the device housing 140 from the opening 151 increases, and the internal pressure of the device housing 140 rises. In addition, at the end of the opening 151 of the developing device 14, the end portion on the upstream side along the rotation direction of the developing roller 141 is blocked by the layer thickness limiting member 144 that limits the layer thickness of the magnetic brush of the developer 4 held on the outer periphery of the developing sleeve 141b and the magnetic brush of the developer 4.

[0101] When the internal pressure of the device housing 140 rises, if no countermeasures are taken, so-called toner cloud is generated in which the colorant flies outward from the area of ​​the developing roller 141 facing the opening 151, and the interior of the device body 1a may be contaminated by the scattered colorant.

[0102] Therefore, the applicant has proposed a device with the following structure, as disclosed in Patent Document 1, comprising: an exhaust channel that discharges the air in the developer accommodating container to the outside; a capturing component that captures the colorant in the exhaust gas passing through the exhaust channel; and a closing component, whose base end is retained in the developer accommodating container and whose front end is clamped by the developer accommodating container and the developer retained on the developer retaining body on the downstream side of the opening along the rotation direction of the developer retaining body to close the gap.

[0103] However, it has been found that in the case of the technology disclosed in Patent Document 1, the following new technical problem arises: as time goes by, the filter, as an example of a capturing component, becomes clogged due to capturing colorant, and the air in the developing device cannot be discharged to the outside through the exhaust passage, the internal pressure of the developer holding container gradually increases, and the colorant becomes scattered colorant and flows out from the area facing the opening of the developer retaining body.

[0104] In order to solve this new technical problem, it is conceivable to dispose a suction duct for sucking scattered toner leaked from the developing device on the back side of the developing device along the longitudinal direction.

[0105] However, it was found that when a suction duct is arranged on the back side of the developing device, since the suction duct is far away from the opening of the developing device, although the scattered colorant can be attracted to a certain extent near the suction channel along the long side of the developing device, the scattered colorant leaked from the front side of the developing device away from the suction duct along the long side cannot be effectively attracted, and the device housing of the developing device is contaminated by the scattered colorant.

[0106] In addition, in response to this new technical problem, in addition to the exhaust channel, in order to capture the scattered colorant flowing out from the opening of the developing device, it is considered to set a suction channel for sucking the scattered colorant leaking from the opening of the developing device to the outside in the entire area along the axial direction of the developer retaining unit of the opening of the developing device.

[0107] The suction passage is functionally arranged at an end portion of the opening of the developing device on the downstream side in the rotation direction of the developer holding unit, that is, at an upper end portion of the developing device in the vertical direction.

[0108] However, as described above, there is an intermediate transfer belt 21 of the intermediate transfer device 20 at the upper part of the developing device 14. Therefore, when a suction channel is configured in addition to the exhaust channel at the upper end part of the developing device 14 along the vertical direction Z, another technical problem arises that the developing device 14 is enlarged, which leads to an increase in the size of the image forming device 1.

[0109] Therefore, in order to avoid the enlargement of the developing device and to take into account the exhaust of air in the developing device and the suction of scattered colorant, the developing device involved in this embodiment 1 has an exhaust channel for exhausting the air in the frame to the outside and a suction channel for sucking the developer leaked from the opening of the frame to the outside, and the exhaust channel and the suction channel are arranged to have different positions along the axial direction of the developer retaining unit.

[0110] That is, Figure 5 As shown, the developing device 14 involved in this embodiment 1 has a double structure in which the area of ​​the device housing 140 located above the developing roller 141 and the stirring and supplying member 142 along the vertical direction Z is separated by the upper housing body 140b' and the channel forming member 140b", and a space 157 that is relatively low in height along the vertical direction Z and long in the horizontal direction X toward the inside of the device housing 140 is formed between the upper housing body 140b' and the channel forming member 140b". The side of the space 157 opposite to the photosensitive drum 11 is opened over substantially the entire length along the axial direction of the developing roller 141.

[0111] In order to form the space 157, the upper housing body 140b' of the developing device 14 has, at the end of the opening 151 on the downstream side along the rotation direction C of the developing roller 141, a covering cylindrical portion 158 that covers a portion of the outer peripheral surface of the developing roller 141 exposed to the outside and forms a cylindrical shape; a curved portion 159 that curves obliquely downward from the back side of the covering cylindrical portion 158 toward the upper part of the stirring and supplying member 142; and a curved portion 160 that curves in a substantially V-shape from the back side of the curved portion 159 toward further downward. A recessed portion 161 that is engaged with the partition wall 152 of the lower housing 140a is provided at the lower end of the curved portion 160. In addition, a side wall 162 on the back side of the curved portion 160 extends to the upper end of the device housing 140. The side wall 162 on the back side forms the space 157 by being engaged with the channel forming member 140b".

[0112] like Figure 3 and Figure 6 As shown, between the upper housing body 140b' and the channel forming member 140b", exhaust channels 163, 163, ... for discharging the air inside the device housing 140 to the outside are formed by dividing a part of the space 157.

[0113] In order to suppress the increase in the internal pressure of the developing device 14, it is desirable that the exhaust passages 163, 163, ... exhaust the internal air to the outside over substantially the entire region of the developing device 14 along the axial direction of the developing roller 141. In addition, since it is necessary to exhaust the air existing in the upper portion of the developer storage chamber 150 along the vertical direction Z inside the device housing 140 of the developing device 14 to the outside, the exhaust passages 163, 163, ... are arranged at the upper portion of the developing device 14 along the vertical direction Z, i.e., at the end portion of the downstream side of the opening 151 of the device housing 140 along the rotation direction of the developing roller 141, and at the same position as the suction passages 167, 167, ... described later, i.e., on the intermediate transfer belt 21 side.

[0114] In this way, the exhaust passages 163, 163... are arranged at the upper part of the device housing 140 along the vertical direction Z, thereby discharging the air in the device housing 140 to the outside without interfering with the developer 4 in the device housing 140, compared with the case where they are arranged at the lower part of the device housing 140 along the vertical direction Z.

[0115] In addition, the position of the exhaust channels 163, 163... along the rotation direction of the developing roller 141 is arranged at the same position as the suction channels 167, 167..., thereby avoiding the enlargement of the developing device 14 compared to the case where the position along the rotation direction C of the developing roller 141 is different from the suction channels 167, 167...

[0116] A plurality of exhaust passages 163, 163, ... are arranged along the axial direction of the developing roller 141. As for each exhaust passage 163, 163, ..., Figure 3 As shown, the end 163a on the outlet side opens at the end on the downstream side of the opening 151 of the device housing 140 along the rotation direction C of the developing roller 141. In addition, for each exhaust passage 163, 163, ..., the end 163b on the inlet side opens at the bent portion 159 of the upper housing body 140b'.

[0117] The end 163b on the inlet side of each exhaust channel 163, 163... is surrounded by a partition wall 164 that is erected on the curved portion 159 of the upper shell body 140b' in a manner that intersects the long side direction of the exhaust channel 163, 163... The partition wall 164 is opened at a position close to the inner surface of the channel forming component 140b", forming the end 163b on the inlet side of each exhaust channel 163, 163... The partition wall 164 prevents the colorant in the developer accommodating chamber 150 from flowing out.

[0118] In addition, the side wall 165 on the back side of the partition wall 164 is extended to the upper end of the device housing 140. The side wall 165 of the partition wall 164 is connected to the channel forming member 140b" to divide the exhaust channels 163, 163... In addition, as shown in FIG. Figure 6 As shown, adjacent exhaust passages 163 , 163 . . . are separated from each other by partition walls 166 .

[0119] In addition, between the upper housing body 140b' and the channel forming member 140b", as shown in FIG. Figure 3 and Figure 6 As shown, suction passages 167, 167 ... are formed by dividing a part of the space 157 to suck toner as an example of developer leaking to the outside from the opening 151 of the device housing 140. A plurality of suction passages 167, 167 ... are arranged in a manner that the positions along the axial direction of the developing roller 141 are all different from the exhaust passages 163, 163 ...

[0120] In this way, the exhaust passages 163 , 163 . . . and the suction passages 167 , 167 . . . are located at different positions along the axial direction of the developing roller 141 , thereby preventing the developing device 14 from being enlarged.

[0121] The suction passages 167, 167 ... are passages for sucking the scattered toner flowing out from the opening 151 of the developing device 14 to the outside, and preferably, the scattered toner flowing out to the outside is sucked over substantially the entire region of the developing device 14 along the axial direction of the developing roller 141. In order to suck the scattered toner flowing out from the opening 151 of the developing device 14 to the outside, the suction passages 167, 167 ... are arranged at the end portion of the opening 151 of the developing device 14 on the downstream side along the rotation direction of the developing roller 141, that is, at the upper portion of the developing device 14 along the vertical direction Z, that is, at the intermediate transfer belt 21 side.

[0122] Each suction channel 167, 167 ... such as Figure 5 As shown, the end portion 167a on the inlet side opens at the end portion of the opening portion 151 of the device housing 140 on the downstream side along the rotation direction of the developing roller 141. That is, each suction passage 167, 167... opens at the end portion of the opening portion 151 of the device housing 140 on the downstream side along the rotation direction of the developing roller 141, that is, at the same position as the exhaust passage 163, 163... In addition, each suction passage 167, 167... is as shown in FIG. Figure 6 As shown, the end portion 167 a on the outlet side is arranged inside the device housing 140 .

[0123] Thus, compared with the case where the opening 151 of the device housing 140 opens on the upstream side along the rotation direction of the developing roller 141 , the suction passages 167 , 167 . . . can effectively suck the toner discharged from the opening 151 as the developing roller 141 rotates.

[0124] The suction passages 167, 167, . . . are connected to each other at an end 167b on the inner side of the device casing 140 and are connected to a communication passage 168 arranged along the axial direction of the developing roller 141.

[0125] Each suction channel 167, 167 ... such as Figure 6 and Figure 7 As shown, by forming exhaust passages 163, 163... in the upper part of the upper housing body 140b', the remaining passage of the space 157 is divided from the exhaust passages 163, 163... That is, the remaining passage area in the space 157 not divided by the exhaust passages 163, 163... becomes the suction passages 167, 167...

[0126] like Figure 3 As shown in FIG. 1 , the communication path 168 is formed as a channel-shaped space located at the end of the back side of the curved portion 159 of the upper housing body 140b' and the upper part of the curved portion 160 in the space 157. The communication path 168 extends to the end of the back side of the developing device 14, as shown in FIG. Figure 8 As shown, the suction fan (not shown) is connected to an example of suction means via a suction duct 169. A filter for removing toner is provided at the exhaust port of the suction fan.

[0127] In the developing device 14 according to the first embodiment, as described above, the exhaust passages 163, 163 ... and the suction passages 167, 167 ... are arranged at different positions along the axial direction of the developing roller 141. That is, the exhaust passages 163, 163 ... and the suction passages 167, 167 ... are not arranged at the same position along the axial direction of the developing roller 141.

[0128] like Figure 6 and Figure 7 As shown in FIG. 1 , the suction passages 167, 167 ... are respectively arranged at both ends along the axial direction of the developing roller 141 and at positions that divide the distance between the both ends into N equal parts (here, N is 4). In addition, among the suction passages 167, 167 ..., the interval between the suction passage 167 located at the end near the front side along the axial direction of the developing roller 141 and the adjacent suction passage 167 is set to be slightly smaller than the intervals between the other suction passages 167.

[0129] In this way, the suction passages 167 , 167 . . . are arranged at both ends along the axial direction of the developing roller 141 , thereby being able to effectively suck the toner leaked from both ends of the opening 151 , compared with a case where the suction passages 167 , 167 . . . are not arranged at both ends along the axial direction of the developing roller 141 .

[0130] In addition, the suction channels 167, 167... are respectively arranged at positions that divide the area between the two end portions along the axial direction of the developing roller 141 into N equal parts, thereby making it easier to suck the colorant leaked from the middle position along the axial direction of the developing roller 141 compared to the case where they are only arranged at the two end portions.

[0131] Furthermore, the suction channels 167, 167... are evenly arranged along the axial direction of the developing roller 141, thereby limiting the number of suction channels 167, 167... and evenly sucking the colorant leaked to the outside from the opening 151, compared with the case where they are unevenly arranged between the two end portions along the axial direction of the developing roller 141.

[0132] In the example shown in the figure, the opening width W1 of the suction passages 167, 167 located at both ends along the axial direction of the developing roller 141 is set larger than the opening width W2 of the other suction passages 167, 167 ..., but the opening width W1 of the suction passages 167, 167 located at both ends may be set equal to or smaller than the opening width W2 of the other suction passages 167, 167 .... In the case where the opening width W1 of the suction passages 167, 167 located at both ends is set smaller than the opening width W2 of the other suction passages 167, 167 ..., the suction wind speed of the suction passages 167, 167 located at both ends can be increased, which is ideal.

[0133] On the other hand, in the developing device 14 according to the first embodiment, as shown in FIG. Figure 6 As shown, the exhaust channels 163, 163... are arranged at a position other than the suction channels 167, 167... along the axial direction of the developing roller 141, that is, adjacent to the suction channels 167, 167... located at the two end portions along the axial direction of the developing roller 141 and the suction channels 167, 167... located in the middle thereof.

[0134] In addition, Figure 6 In the embodiment, the adjacent exhaust passages 163, 163 ... are divided from each other by the partition wall 166, but the adjacent exhaust passages 163, 163 ... may be formed as a series of exhaust passages 163 without being separated from each other by the partition wall 166. However, when the adjacent exhaust passages 163, 163 ... are separated from each other by the partition wall 166, the exhaust direction of the exhaust passages 163, 163 ... can be directed to a direction intersecting with the axial direction of the developing roller 141.

[0135] <Function of the developing device>

[0136] In the above structure, in the developing device involved in this embodiment 1, as described below, compared with the case where the exhaust channel and the suction channel are all arranged at the same position along the axial direction of the developer retaining unit, it is possible to avoid enlarging the developing device and take into account both the exhaust of air in the developing device and the suction of scattered colorant.

[0137] That is, in the image forming apparatus 1 to which the developing device 14 according to the first embodiment is applied, as shown in FIG. Figure 1 and Figure 2 As shown, in each image generating device 10 (Y, M, C, K), an electrostatic latent image is formed on the surface of the photosensitive drum 11, and the electrostatic latent image formed on the surface of the photosensitive drum 11 is developed by the corresponding developing device 14.

[0138] In the developing device 14, as Figure 3 As shown, the developing roller 141, the stirring and supplying component 142 and the stirring and conveying component 143 are driven to rotate in the required rotation direction, and the electrostatic latent image on the surface of the photosensitive drum 11 is visualized and developed through the colorant by utilizing the magnetic brush of the developer 4 held on the surface of the developing sleeve 141b of the developing roller 141.

[0139] like Figure 3 As shown, the developing device 14 drives the developing roller 141 to rotate at a required speed along the arrow direction C. Therefore, as the developing roller 141 rotates, external air is introduced into the interior of the device housing 140 from the opening 151, and the internal pressure tends to rise.

[0140] However, if Fig. 9 As shown, the developing device 14 according to the first embodiment is provided with a plurality of exhaust passages 163, 163, ... along the axial direction of the developing roller 141, so that the air in the device housing 140 is discharged to the outside through the exhaust passages 163, 163, .... Therefore, in the developing device 14 in which the rotation speed of the developing roller 141 is increased to improve productivity, it is possible to suppress the internal pressure of the device housing 140 from rising and the toner from scattering from the opening 151 to the outside of the developing device 14.

[0141] In addition, if Fig.10As shown, the developing device 14 according to the first embodiment is provided with a plurality of suction passages 167, 167, ... along the axial direction of the developing roller 141. Therefore, in the developing device 14, even if there is a possibility that toner may leak out from the opening 151 of the device housing 140 or the exhaust passages 163, 163, ..., the toner leaking out from the opening 151, the exhaust passages 163, 163, ... can be sucked out by the plurality of suction passages 167, 167, .... Therefore, in the developing device 14 in which the rotation speed of the developing roller 141 is increased to improve productivity, even if toner leaks out from the opening 151, it can be suppressed from floating inside the image forming device.

[0142] Furthermore, in the developing device 14 according to the first embodiment, as shown in FIG. Figure 6 and Figure 7 As shown, a plurality of exhaust passages 163, 163, ... and a plurality of suction passages 167, 167, ... are arranged along the axial direction of the developing roller 141, and all have different positions.

[0143] As a result, when the developing device 14 is provided with a plurality of exhaust passages 163, 163... and a plurality of suction passages 167, 167... at the end portion on the downstream side of the opening portion 151 of the device housing 140 along the rotation direction of the developing roller, i.e., at the upper portion of the device housing 140 along the vertical direction Z, there is no need to arrange the exhaust passages 163, 163... and the suction passages 167, 167... in a so-called double-layer structure at the same position along the axial direction of the developing roller 141, i.e., at the upper portion of the device housing 140 along the vertical direction Z. This can avoid the enlargement of the developing device 14 and thus the enlargement of the image forming device 1, and can take into account both the exhaust of air in the developing device 14 and the attraction of scattered colorant.

[0144] [Implementation method 2]

[0145] Fig.11 It is a diagram showing the structure of a developing device according to Embodiment 2 of the present invention.

[0146] like Fig.11 As shown, the developing device 14 according to the second embodiment is configured such that the end 163a of the exhaust passages 163, 163 ... at the outlet side is completely blocked by a filter member 170 as an example of a capture unit. The filter member 170 is provided at the end 163a of the exhaust passages 163, 163 ... at the outlet side by bonding or other means.

[0147] Thus, in the case of the developing device 14 according to the second embodiment, the filter member 170 can capture the toner exhausted to the outside together with the air from the exhaust ducts 163, 163, ..., and prevent the toner from leaking to the outside from the exhaust ducts 163, 163, ...

[0148] In addition, in the developing device 14 involved in the above-mentioned embodiment 2, when the filter component 170 arranged at the outlet portion of the exhaust channel 163, 163... is clogged with colorant over time, since the suction channels 167, 167... are arranged along the axial direction of the developing roller 141 of the device housing 140, the colorant leaked to the outside from the opening portion 151 of the device housing 140 can also be sucked from the suction channels 167, 167..., and the colorant can be prevented or suppressed from leaking to the outside from the opening portion 151 over time.

[0149] The other structures and functions are the same as those in the above-mentioned embodiment 1, so their description is omitted.

[0150] [Implementation method 3]

[0151] Fig.12 It is a diagram showing the structure of a developing device according to Embodiment 3 of the present invention.

[0152] The developing device 14 involved in this embodiment 3 is not configured to completely block the end portions 163a on the outlet side of the exhaust passages 163, 163... using the filter component 170 as an example of a capturing unit, but is configured to block a portion of the end portions 163a on the outlet side of the exhaust passages 163, 163... using the filter component 170 as an example of a capturing unit.

[0153] That is, in the developing device 14 according to the third embodiment, Fig.12 As shown, the end 163a on the outlet side of one or more exhaust channels 163, 163... adjacent to the suction channel 167, 167... is directly opened, and the end 163a on the outlet side of the exhaust channels 163, 163... not adjacent to the suction channel 167, 167... is blocked by the filter component 170.

[0154] In the developing device 14 according to the third embodiment, by blocking the end 163 a on the outlet side of the exhaust passages 163 , 163 . . . by the filter member 170 , the toner leaking from the exhaust passages 163 , 163 . . . to the outside can be captured by the filter member 170 .

[0155] Furthermore, in the developing device 14 , even when the filter member 170 is clogged with toner over time, the air inside the device housing 140 can be reliably discharged to the outside through the other exhaust passages 163 , 163 . . . . .

[0156] Furthermore, when toner leaks from the exhaust passages 163 , 163 . . . where the filter member 170 is not provided, the toner leaked to the outside can also be sucked from the adjacent suction passages 167 , 167 . . .

[0157] The other structures and functions are the same as those in the above-mentioned embodiment 1, so their description is omitted.

[0158] [Implementation method 4]

[0159] Fig.13 It is a diagram showing the structure of a developing device according to a fourth embodiment of the present invention.

[0160] In the developing device involved in this embodiment 4, the suction channel is arranged at multiple locations including the two end portions and the central portion along the axial direction of the developer retaining unit, and the exhaust channel is constructed so that the exhaust channel adjacent to the suction channel arranged at positions other than the two end portions and the central portion along the axial direction of the developer retaining unit is blocked.

[0161] In addition, the developing device according to the fourth embodiment is configured such that a portion of the exhaust passage along the axial direction of the developer holding unit is blocked, and the blocked exhaust passage communicates with the suction passage.

[0162] That is, Fig.13 As shown, in the developing device 14 involved in this embodiment 4, the suction passages 167, 167 ... are opened at both ends and the center portion along the axial direction of the developing roller 141. In addition, the suction passages 167, 167 located at positions other than the both ends and the center portion along the axial direction of the developing roller 141 are blocked by the shielding plate 171.

[0163] In addition, the exhaust channels 163, 163... are constructed as multiple exhaust channels 163, 163... adjacent to the suction channels 167, 167 blocked by the shielding plate 171 on both sides, which are blocked by the same shielding plate 171, and these multiple blocked exhaust channels 163, 163... are connected to the blocked suction channels 167, 167 via gaps at the ends on their outlet sides.

[0164] In addition, Fig.13 In the figure, for the sake of convenience of explanation, the shielding plate 171 is separated from the exhaust channels 163, 163... and the suction channels 167, 167, but the shielding plate 171 is fixed to the device housing 140 by means of bonding or the like, thereby blocking these exhaust channels 163, 163... and the suction channels 167, 167.

[0165] In the developing device involved in this embodiment 4, the end of the outlet side of the exhaust passage 163, 163... is blocked by using a shielding plate 171 to prevent colorant from leaking to the outside from the exhaust passage 163, 163..., and the exhaust passage 163, 163... is connected to the suction passage 167, 167 to discharge the air inside the device housing 140 from the exhaust passage 163, 163... through the suction passage 167, 167, thereby ensuring the function of preventing or suppressing the internal pressure from rising.

[0166] Furthermore, at both end portions and the center portion along the axial direction of the developing roller 141 , the toner leaking to the outside can be reliably sucked through the suction passages 167 , 167 . ...

[0167] The other structures and functions are the same as those in the above-mentioned embodiment 1, so their description is omitted.

[0168] Furthermore, in the above-mentioned embodiment, the case where the invention is applied to a full-color image forming apparatus has been described, but it is needless to say that the invention can also be applied to a monochrome image forming apparatus in the same manner.

[0169] In the above embodiment, the case where five suction channels are arranged along the axial direction of the developer holding member is described, but the number and arrangement of the suction channels are arbitrary, and may be more or less than five.

[0170] (Note) (((1)))

[0172] A developing device, characterized by comprising:

[0173] a frame that accommodates a developer;

[0174] A developer holding unit, which is arranged at an opening of the frame body opposite to the image holding body, and holds the developer and rotates;

[0175] An exhaust passage, which discharges the air in the frame to the outside;

[0176] a suction passage for sucking the developer leaking from the opening of the frame to the outside,

[0177] The exhaust passage and the suction passage are arranged at different positions along the axial direction of the developer holding unit. (((2)))

[0179] The developing device according to (((1))), wherein:

[0180] The suction passage is disposed on a downstream side of an opening portion of the frame body in a rotation direction of the developer holding unit. (((3)))

[0182] The developing device according to (((1))), wherein:

[0183] The exhaust duct is disposed at an upper portion of the frame along a vertical direction. (((4)))

[0185] The developing device according to (((3))), wherein:

[0186] The exhaust passage is disposed on a downstream side of the opening of the frame in the rotation direction of the developer holding unit and at the same position as the suction passage when viewed from the rotation axis direction of the developer holding unit. (((5)))

[0188] The developing device according to (((1))), wherein:

[0189] The suction passage is disposed at least at both end portions along the axial direction of the developer holding unit. (((6)))

[0191] The developing device according to (((5))), wherein:

[0192] The suction passage is further arranged between the suction passages arranged at both end portions along the axial direction of the developer holding unit. (((7)))

[0194] The developing device according to (((6))), wherein:

[0195] The suction passages are respectively arranged at positions divided into N equal parts along the axial direction of the developer holding unit, where N is an integer greater than or equal to 2. (((8)))

[0197] The developing device according to (((5))), wherein:

[0198] The exhaust passage is arranged at a position other than the suction passage along the axial direction of the developer holding unit. (((9)))

[0200] The developing device according to (((1))), wherein:

[0201] The exhaust passage includes, at an outlet portion thereof, a catching unit for catching the developer leaking from the exhaust passage to the outside. (((10)))

[0203] The developing device according to (((9))), wherein:

[0204] The capture unit is arranged on all the exhaust passages. (((11)))

[0206] The developing device according to (((9))), wherein:

[0207] The capture unit is provided outside the exhaust passage adjacent to the suction passage. (((12)))

[0209] The developing device according to (((1))), wherein:

[0210] A portion of the exhaust passage along the axial direction of the developer holding unit is blocked, and the blocked exhaust passage communicates with the suction passage. (((13)))

[0212] The developing device according to (((12))), wherein:

[0213] The suction passage is provided at a plurality of locations including both end portions and a central portion along the axial direction of the developer holding unit.

[0214] The exhaust passage is blocked at a position adjacent to the suction passage arranged at a position other than both end portions and a center portion of the suction passage in the axial direction of the developer holding unit. (((14)))

[0216] An image forming device, characterized in that it comprises:

[0217] an image holding unit that holds an electrostatic latent image; and

[0218] a developing unit that develops the electrostatic latent image of the image holding unit,

[0219] As the developing unit, the developing device described in any one of (((1))) to (((13))) is used.

[0220] According to the developing device involved in (((1))), compared with the case where the exhaust passage and the suction passage are arranged at the same position along the axial direction of the developer retaining unit, it is possible to avoid enlarging the developing device and take into account both the exhaust of air in the developing device and the suction of scattered colorant.

[0221] According to the developing device of (((2))), the developer discharged as the developer holding unit rotates can be effectively sucked compared to a case where the suction passage is arranged on the upstream side of the opening of the frame in the rotation direction of the developer holding unit.

[0222] According to the developing device according to (((3))), compared with a case where the exhaust duct is arranged at the lower portion of the frame in the vertical direction, the air in the frame can be exhausted to the outside without interfering with the developer in the frame.

[0223] According to the developing device of (((4))), compared with a case where the position of the exhaust passage along the rotation direction of the developer holding unit is different from that of the suction passage, the size of the developing device can be avoided.

[0224] According to the developing device of (((5))), the developer leaked to the outside from the opening can be effectively sucked compared to a case where the suction passage is not arranged at both end portions along the axial direction of the developer holding unit.

[0225] According to the developing device of (((6))), compared with a case where the suction passages are arranged only at both ends of the developer holding unit in the axial direction, it is easier to suck the developer leaked from the middle position in the axial direction of the developer holding unit.

[0226] According to the developing device of (((7))), compared with a case where the suction passage is unevenly arranged in the axial direction of the developer holding unit, the developer leaked to the outside from the opening can be uniformly sucked.

[0227] According to the developing device of (((8))), compared with a case where a part or all of the exhaust passage overlaps with the suction passage in the axial direction of the developer holding unit, an increase in size of the developing device can be avoided.

[0228] According to the developing device according to (((9))), leakage of developer from the exhaust duct can be suppressed compared with a case where the exhaust duct does not include a catching unit at its outlet for catching developer leaking from the exhaust duct to the outside.

[0229] According to the developing device according to (((10))), compared with a case where the capture unit is provided in a part of the exhaust passage, it is possible to reduce the developer leaking from the exhaust passage.

[0230] According to the developing device according to (((11))), compared with a case where the trap unit is provided in all exhaust passages, it is possible to suppress a reduction in exhaust effect due to clogging of the developer in the trap unit.

[0231] According to the developing device according to (((12))), compared with the case where only the exhaust passage is blocked, the exhaust effect of the exhaust passage can be maintained.

[0232] According to the developing device of (((13))), compared with the case where the exhaust passage is blocked regardless of the positional relationship with the suction passage, it is possible to achieve a better balance between exhausting the air in the developing device and suctioning the scattered toner.

[0233] According to the developing device involved in (((14))), compared with the case where the developing device described in any one of (((1))) to (((13))) is not used as the developing unit, it is possible to achieve both the exhaust of air in the developing device and the suction of scattered colorant.

Claims

1. A developing device, characterized in that: have: a frame that accommodates a developer; A developer holding unit, which is arranged at an opening of the frame body opposite to the image holding body, and holds the developer and rotates; an exhaust passage for exhausting the air in the frame to the outside; as well as a suction passage for sucking the developer leaking from the opening of the frame to the outside, The exhaust passage and the suction passage are arranged at different positions along the axial direction of the developer holding unit.

2. The developing device according to claim 1, wherein: The suction passage is arranged on the downstream side of the opening portion of the frame body in the rotation direction of the developer holding unit.

3. The developing device according to claim 1, wherein: The exhaust duct is arranged at an upper portion of the frame along a vertical direction.

4. The developing device according to claim 3, wherein: The exhaust passage is arranged at a downstream side of the opening of the frame along the rotation direction of the developer holding unit and at the same position as the suction passage when viewed from the rotation axis direction of the developer holding unit.

5. The developing device according to claim 1, wherein: The suction passage is disposed at least at both end portions along the axial direction of the developer holding unit.

6. The developing device according to claim 5, wherein: The suction passage is further arranged between the suction passages arranged at both end portions along the axial direction of the developer holding unit.

7. The developing device according to claim 6, wherein: The suction passages are respectively arranged at N equally divided positions along the axial direction of the developer holding unit, where N is an integer greater than or equal to 2.

8. The developing device according to claim 5, wherein: The exhaust passage is arranged at a position other than the suction passage along the axial direction of the developer holding unit.

9. The developing device according to claim 1, wherein: The exhaust passage includes, at its outlet, a catching unit for catching the developer leaking from the exhaust passage to the outside.

10. The developing device according to claim 9, wherein: The capture unit is arranged on all the exhaust passages.

11. The developing device according to claim 9, wherein: The capture unit is provided outside the exhaust passage adjacent to the suction passage.

12. The developing device according to claim 1, wherein: A portion of the exhaust passage along the axial direction of the developer holding unit is blocked, and the blocked exhaust passage communicates with the suction passage.

13. The developing device according to claim 12, wherein: The suction passage is provided at a plurality of locations including both end portions and a central portion along the axial direction of the developer holding unit. The exhaust passage is blocked at a position adjacent to the suction passage arranged at a position other than both end portions and a center portion of the suction passage in the axial direction of the developer holding unit.

14. An image forming device, characterized in that: have: an image holding unit that holds an electrostatic latent image; and a developing unit that develops the electrostatic latent image of the image holding unit, As the developing unit, the developing device according to any one of claims 1 to 13 is used.

Images