Image forming apparatus

Abstract

To provide a filter through which both an airflow for exhausting air near a corona charger and an airflow for exhausting air near a developing unit pass, and allow individual control of the airflows.SOLUTION: A charging exhaust duct 112 through which air including ozone passes, and a development exhaust duct 122 through which air including toner passes are formed in a duct unit 300. The duct unit 300 is disposed with a toner filter 125, an ozone filter 115, a charging exhaust fan 111, and a development exhaust fan 121. The inside of the duct unit 300 is partitioned into a charging exhaust chamber 301 and a development exhaust chamber 302 by ribs 161, 162, 163, and the ozone filter 115 is arranged over the charging exhaust chamber 301 and the development exhaust chamber 302. Airflows do not interfere with each other in the charging exhaust chamber 301 and the development exhaust chamber 302. Consequently, the airflows in the charging exhaust chamber 301 and the development exhaust chamber 302 can be individually controlled.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] As an image forming apparatus, a corona charging type image forming apparatus has been conventionally proposed. In the case of the corona charging method, a corona charger generates corona discharge to charge the surface of the photoreceptor, and ozone is generated as a by-product of the corona discharge. However, ozone may corrode, for example, the grid of the corona charger. Therefore, a duct is disposed near the corona charger, an air flow is formed in the duct by a fan, and ozone discharged from the corona charger by air is sent to an ozone filter installed in the duct and recovered. As the ozone filter, for example, one that decomposes ozone into oxygen using a catalyst or one that adsorbs ozone to activated carbon is used.

[0003] An image forming apparatus is provided with a developing device that develops an electrostatic latent image formed on a photoreceptor with toner. Since toner is used in the developing device, the toner is likely to scatter. And since the developing device is provided relatively near the corona charger, toner may be mixed into the air flow for exhausting the air near the corona charger, and ozone may be mixed into the air flow for exhausting the air near the developing device. Therefore, conventionally, in order to miniaturize the image forming apparatus by sharing components, a device provided with an aggregated duct that aggregates the air flow for exhausting the air near the corona charger and the air flow for exhausting the air near the developing device has been proposed (Patent Document 1). In the aggregated duct, one fan for generating an air flow for exhausting the air near the corona charger and an air flow for exhausting the air near the developing device, a toner filter and an ozone filter are disposed.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Patent No. 6594058 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in order to recover ozone or toner more efficiently, it is preferable to have a configuration in which the airflow for exhausting the air near the corona charger and the airflow for exhausting the air near the developer can be controlled independently. In the case of the apparatus described in Patent Document 1 mentioned above, since one fan generates the airflow for exhausting the air near the corona charger and the airflow for exhausting the air near the developer, it was difficult to control each airflow independently.

[0006] The present invention aims to provide an image forming apparatus that allows for individual control of each airflow, even when the filters passing through the airflow for exhausting air near the corona charger and the airflow for exhausting air near the developer are shared. [Means for solving the problem]

[0007] An image forming apparatus according to one embodiment of the present invention is an image forming apparatus for forming an image on a recording material, comprising: an image forming unit having a rotationally driven photoreceptor; a corona charging device for charging the photoreceptor; an exposure device for forming an electrostatic latent image on the charged photoreceptor; and a developing device for developing the electrostatic latent image formed on the photoreceptor into a toner image using toner; and a first duct having a first air intake port for drawing in air containing ozone generated when the charging device charges the photoreceptor; and a second duct having a second air intake port for drawing in air containing toner scattered when the developing device develops the electrostatic latent image. The image forming apparatus is characterized by comprising: a duct unit that guides air drawn in from the first and second intake ports to the outside of the image forming apparatus; a first fan that generates a first airflow in the first duct so that air is drawn in from the first intake port; a second fan that generates a second airflow in the second duct so that air is drawn in from the second intake port; and an ozone filter that is detachably provided to both the first and second ducts, is arranged across the first and second ducts, and removes ozone contained in the first and second airflows. [Effects of the Invention]

[0008] According to the present invention, even when the filters that pass through the airflow for exhausting air near the corona charging device and the airflow for exhausting air near the developing device are shared, it is easy to individually control each airflow. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the image forming apparatus of this embodiment. [Figure 2] A schematic side view showing the airflow configuration for the image forming unit. [Figure 3] A schematic top view showing the airflow configuration and various filters related to ozone recovery. [Figure 4] A cross-sectional view showing a duct unit. [Figure 5]A perspective view showing the toner filter. [Figure 6] (a) Perspective view showing an ozone filter, (b) Perspective view showing an example of the cross-sectional shape of an ozone filter, (c) Cross-sectional view showing another example of the cross-sectional shape of an ozone filter. [Figure 7] A cross-sectional view showing the duct unit when the cross-sectional area ratio of the toner filter is changed. [Figure 8] (a) Diagram showing the arrangement when the fans are of different sizes, (b) Diagram showing the arrangement when the fans are of the same size. [Figure 9] A control block diagram illustrating the control unit. [Figure 10] A flowchart illustrating the filter replacement notification process. [Modes for carrying out the invention]

[0010] <Image forming apparatus> The following describes this embodiment. First, the image forming apparatus of this embodiment will be described with reference to Figure 1. The image forming apparatus 100 shown in Figure 1 is a full-color printer of the intermediate transfer tandem type, in which yellow, magenta, cyan, and black image forming units Pa, Pb, Pc, and Pd are arranged along an intermediate transfer belt 20. Examples of recording materials S that can be used with the image forming apparatus 100 include plain paper, cardboard, rough paper, textured paper, coated paper, etc.

[0011] The recording material transport process of the image forming apparatus 100 will now be described. The recording material S is stored in a stacked form within the paper feed cassette 10 and is fed out from the paper feed cassette 10 by the paper feed roller 13 in accordance with the image formation timing. The recording material S fed out by the paper feed roller 13 is transported to the register roller 12 located in the middle of the transport path 414. After the register roller 12 corrects the skewness and timing of the recording material S, the recording material S is sent to the secondary transfer section T2. ​​The secondary transfer section T2 is a transfer nip section formed by the secondary transfer inner roller 21 and the secondary transfer outer roller 11, and a toner image is transferred onto the recording material in response to, for example, the application of a secondary transfer voltage to the secondary transfer outer roller 11.

[0012] Next, we will explain the image formation process, which takes place at the same timing as the transport process of the recording material S to the secondary transfer unit T2 described above. First, we will explain the image forming units. The image forming units Pa, Pb, Pc, and Pd for each color are configured almost identically, except that the toner colors used in the developing units 1a, 1b, 1c, and 1d are yellow, magenta, cyan, and black. Therefore, in the following, we will explain the yellow image forming unit Pa as a representative example, and omit explanations for the other image forming units Pb, Pc, and Pd.

[0013] The image forming unit Pa mainly consists of a developing device 1a, a charging device 2a, a photosensitive drum 3a, a photosensitive drum cleaner 4a, and an exposure device 5a. The photosensitive drum 3a, which acts as a photoreceptor and is rotated in the direction of arrow R1 in the figure, is uniformly charged on its surface by the charging device 2a, and then an electrostatic latent image is formed by the exposure device 5a, which is driven based on an image information signal. In this embodiment, the charging device 2a is a corona charging device. Next, the electrostatic latent image formed on the photosensitive drum 3a is developed into a toner image using a developer by the developing device 1a. Then, in response to the application of a primary transfer voltage to the primary transfer roller 6a, which is positioned between the image forming unit Pa and the intermediate transfer belt 20, the toner image formed on the photosensitive drum 3a is primary transferred onto the intermediate transfer belt 20. The remaining primary transfer toner that remains slightly on the photosensitive drum 3a is collected by the photosensitive drum cleaner 4a. In this embodiment, the image forming units Pa to Pd are examples of image forming units.

[0014] The intermediate transfer belt 20 is stretched by the secondary transfer inner roller 21, the tension roller 22, and the stretching roller 23, and is driven in the direction of arrow R2 in the figure. The image forming processes for each color that are processed in parallel by the image forming units Pa to Pd are performed at the timing of sequentially overlapping on the toner image of the upstream color that has been primarily transferred onto the intermediate transfer belt 20. As a result, finally, a full-color toner image is formed on the intermediate transfer belt 20 and is conveyed to the secondary transfer unit T2. Incidentally, the secondary transfer residual toner after passing through the secondary transfer unit T2 is recovered by the belt cleaner device 30.

[0015] As described above, with the conveyance process and the image forming process respectively described, at the secondary transfer unit T2, the timing of the recording material S and the full-color toner image coincides, and secondary transfer is performed. After that, the recording material S is conveyed to the fixing device 50, and a toner image is fixed on the recording material by applying a predetermined pressure and heat. The recording material S on which the toner image has been thus fixed is sandwiched and conveyed by the discharge rollers 14a and 14b and is discharged onto the paper discharge tray 420 as it is in the case of the single-sided printing mode. On the other hand, in the case of double-sided image formation, the conveyance path is switched from the path following the paper discharge tray 420 to the double-sided conveyance path 411 by the switching flapper 410, and the recording material S that is sandwiched and conveyed by the discharge rollers 14a and 14b is sent to the double-sided conveyance path 411. Then, the front and rear ends are reversed by the reversing roller 412 and are sent again to the conveyance path 414 via the double-sided conveyance path 413. The conveyance thereafter and the image forming process for the back side (second side) are the same as those described above, so the description is omitted.

[0016] <Airflow configuration> Next, the airflow configuration related to the recovery of ozone generated by the corona discharge of the photosensitive drums 3a to 3d in the charging devices 2a to 2d and various filters will be described using FIGS. 2 and 3. However, in FIGS. 2 and 3, the charging device 2a will be described as a representative example.

[0017] The charging device 2a ionizes the air around the charging wire 201 by corona discharge to generate ions and charges the photosensitive drum 3a. In order to generate ions by corona discharge, it is necessary to supply air to the charging device 2a. Therefore, a charging intake duct 102 for supplying air to the charging device 2a is disposed on the upstream side in the rotation direction of the photosensitive drum 3a in the vicinity of the charging device 2a. However, the charging device 2a generates not only ions but also ozone during corona discharge. Ozone may corrode, for example, a stainless steel grid (not shown) of the charging device 2a and reduce the charging function of the charging device 2a, so it is necessary to recover it promptly. Therefore, in order to send ozone to the ozone filter 115 (see FIG. 3) by air and recover it, as shown in FIG. 2, a charging exhaust duct 112 is disposed on the downstream side in the rotation direction of the photosensitive drum 3a in the vicinity of the charging device 2a.

[0018] The charging intake duct 102 forms a ventilation path for guiding air to the charging device 2a, and a charging intake fan 101 is disposed on the intake port side of the charging intake duct 102. The charging intake fan 101 takes in air through a dust filter 105 (see FIG. 3) and sends the taken-in air into the charging intake duct 102. The dust filter 105 is a fibrous filter that removes foreign substances such as dust and dirt from the air inhaled by the charging intake fan 101. The charging intake duct 102 is connected to the charging device 2a via an intake duct connection portion 103 on the outlet side in order to guide the air (denoted as air Q1) after removing foreign substances to the charging device 2a. A plurality of open outlets (not shown) for blowing air are formed side by side in the longitudinal direction in the intake duct connection portion 103 in order to uniformly blow air in the longitudinal direction of the charging device 2a.

[0019] As shown in Figure 3, the air Q1 blown in from the intake duct connection 103 passes through the charging device 2a (third airflow). At this time, ozone generated due to corona discharge is included in the air Q1 and discharged together from the charging device 2a (referred to as air Q2). The first duct, the electrostatic exhaust duct 112, forms an air passage for guiding the air Q2 containing ozone discharged from the charging device 2a to the ozone filter 115 via the first communication section 301a (first intake port). An electrostatic exhaust fan 111 for exhausting air is located on the exhaust side of the first communication section 301a. The electrostatic exhaust duct 112 is connected to the charging device 2a via the exhaust duct connection 113 on the intake port 112a side opposite to the first communication section 301a in order to guide the air Q2 containing ozone to the ozone filter 115. The exhaust duct connection section 113 has an opening (not shown) that extends along the longitudinal direction in order to uniformly draw in air Q2 along the longitudinal direction of the charging device 2a.

[0020] As will be explained in more detail later, the electrostatic exhaust fan 111, which acts as the first fan, is installed in a duct unit 300 that collects exhaust from the electrostatic exhaust duct 112 and the developing exhaust duct 122. The electrostatic exhaust fan 111 generates airflow within the electrostatic exhaust duct 112 (the first duct). The ozone filter 115 is installed in the duct unit 300 together with the toner filter 125 (see Figure 4, which will be explained later).

[0021] The ozone-containing air Q2 is sent from the electrostatic exhaust duct 112 into the duct unit 300, where the ozone is recovered by the ozone filter 115 installed in the duct unit 300 and then exhausted. The airflow of the electrostatic intake fan 101 and the electrostatic exhaust fan 111 are set so that the airflow of air Q1 and air Q2 is "Q2 > Q1". This allows more ozone to be contained in air Q2 and discharged from the electrostatic device 2a compared to when the airflow is "Q2 ≤ Q1", and less ozone remains in the electrostatic device 2a. In other words, the ozone generated in the electrostatic device 2a can be properly discharged from the electrostatic device 2a by the air.

[0022] Next, the airflow configuration for collecting toner scattered during toner image development in developing units 1a to 1d will be explained using Figures 2 and 3. Figures 2 and 3 will use developing unit 1a as a representative example. Note that in Figure 3, the main body of developing unit 1a is omitted for illustrative purposes.

[0023] In the image forming apparatus 100, toner is supplied from the developing unit 1a to the photosensitive drum 3a to develop the toner image. However, conventionally, some toner (referred to as "scattered toner") would scatter outside the developing unit 1a without being supplied to the photosensitive drum 3a. This scattered toner could contaminate the image forming apparatus 100 and cause image defects. Therefore, to collect the scattered toner by sending it to the toner filter 125 (see Figure 3) using air, a developing exhaust duct 122 is provided near the developing unit 1a, as shown in Figure 2.

[0024] The developing exhaust duct 122, which serves as the second duct, forms a ventilation passage for guiding air to the outside of the image forming apparatus 100, and the intake side of the developing exhaust duct 122 is connected to the toner recovery duct connection section 123. The toner recovery duct connection section 123 is located below the developing apparatus 1a, and an opening (not shown) is formed therein to uniformly take in air Q3 (described later) from below the developing apparatus 1a in the longitudinal direction. A developing exhaust fan 121, which serves as the second fan, is located on the exhaust side of the developing exhaust duct 122. The developing exhaust fan 121 generates airflow inside the developing exhaust duct 122 (inside the second duct). Due to the airflow generated by the developing exhaust fan 121, scattered toner is included in the air (referred to as air Q3) and discharged from the developing apparatus 1a. Air Q3 containing scattered toner is sent from the developing exhaust duct 122 into the duct unit 300, where the scattered toner is collected by the toner recovery filter 125 installed in the duct unit 300 and then exhausted. The developing exhaust fan 121 is installed in the duct unit 300 together with the electrostatic exhaust fan 111. In other words, the electrostatic exhaust fan 111 and the developing exhaust fan 121 are installed separately in the duct unit 300.

[0025] Even if the airflow rate of air Q3 is smaller than that of air Q1 and air Q2, scattered toner can still be sent to the toner filter 125 for collection. Conversely, if the airflow rate of air Q3 is increased to match that of air Q2, the scattered toner may pass through the toner filter 125, preventing the toner filter 125 from collecting it. In addition, an increase in the airflow rate of air Q3 may affect the image formed on the photosensitive drum 3a. Therefore, in this embodiment, the airflow rate of air Q3 is set to be smaller than that of air Q2. Specifically, the airflow rate of the developer exhaust fan 121 is controlled to be smaller than that of the electrostatic exhaust fan 111. Furthermore, the developer exhaust duct 122 may be formed to have a smaller cross-sectional area than the electrostatic intake duct 102 and the electrostatic exhaust duct 112. Furthermore, the cross-sectional area of ​​the air Q2 intake port 301b in the first communication section 301a of the developing exhaust duct 122 may be smaller than the cross-sectional area of ​​the air Q2 intake port 112a in the electrostatic exhaust duct 112 (see Figure 3).

[0026] <Duct Unit> Next, the duct unit 300 will be described using Figure 4. The duct unit 300 is formed in a roughly box shape from a resin such as PC-ABS. As shown in Figure 4, the duct unit 300 is equipped with an electrostatic exhaust fan 111 and a developing exhaust fan 121, and an electrostatic exhaust duct 112 and a developing exhaust duct 122 are connected to it.

[0027] The interior of the duct unit 300 is divided into an electrostatic exhaust chamber 301 and a developing exhaust chamber 302 by ribs 161, 162, and 163 acting as partition members. The electrostatic exhaust chamber 301 forms a duct leading from a connected electrostatic exhaust duct 112 to an electrostatic exhaust fan 111, and the developing exhaust chamber 302 forms a duct leading from a connected developing exhaust duct 122 to an developing exhaust fan 121. In this embodiment, the first connecting section 301a, which allows air to pass through the electrostatic exhaust chamber 301 and the electrostatic exhaust duct 112, is an example of a first air intake port, and the second connecting section 302a, which allows air to pass through the developing exhaust chamber 302 and the developing exhaust duct 122, is an example of a second air intake port. The interior of the duct unit 300 is partitioned by ribs 161, 162, and 163, so that the airflow generated by the electrostatic exhaust fan 111 and the de-emission exhaust fan 121 within the duct unit 300 (inside the duct unit) does not interfere with each other.

[0028] Inside the duct unit 300, a toner filter 125 is installed upstream of the direction of airflow (airflow direction: arrow Y direction) generated by the electrostatic exhaust fan 111 and the developer exhaust fan 121, and an ozone filter 115 is installed downstream of the toner filter 125. Each toner filter 125 is individually removable and installed in the electrostatic exhaust chamber 301 and the developer exhaust chamber 302. Each toner filter 125 is fitted into a fitting portion 164 provided on the duct unit 300 and the rib 161, so that they are positioned in the width direction intersecting the first airflow and second airflow (arrow Y direction) flowing through the electrostatic exhaust chamber 301 and the developer exhaust chamber 302. In other words, the toner filter 125 provided in the electrostatic exhaust chamber 301 is a filter that removes toner contained in the first airflow (flow of air Q2) generated by the electrostatic exhaust fan 111, and the toner filter 125 provided in the developing exhaust chamber 302 is a filter that removes toner contained in the second airflow (flow of air Q3) generated by the developing exhaust fan 121.

[0029] Furthermore, the amount of scattered toner contained in the air flowing from the electrostatic exhaust duct 112 into the electrostatic exhaust chamber 301 is often negligible compared to the amount of scattered toner contained in the air flowing from the developer exhaust duct 122 into the developer exhaust chamber 302. Therefore, a toner filter 125 does not need to be installed in the electrostatic exhaust chamber 301.

[0030] In this embodiment, a single ozone filter 115 is detachably installed spanning the electrostatic exhaust chamber 301 and the developing exhaust chamber 302. The single ozone filter 115 is fitted into a fitting portion 165 provided on the duct unit 300. As a result, the ozone filter 115 is positioned across the electrostatic exhaust chamber 301 and the developing exhaust chamber 302, in a width direction that intersects the first airflow and the second airflow (arrow Y direction) flowing through the electrostatic exhaust chamber 301 and the developing exhaust chamber 302. Therefore, the ozone filter 115 is capable of removing ozone contained in the first airflow flowing through the electrostatic exhaust chamber 301 and the second airflow flowing through the developing exhaust chamber 302. Furthermore, since only one ozone filter 115 is needed, it is easy to replace, and the number of ozone filters to be kept in stock as consumables can be reduced, thus easing the burden of filter inventory management.

[0031] <Toner filter> An example of a toner filter 125 is shown in Figure 5. As shown in Figure 5, the toner filter 125 is an electrostatic filter made of a pleated fiber material, for example, a nonwoven fabric 125d folded in a mountain-and-valley pattern inside an outer frame 125c that surrounds all four sides. It is not limited to this as long as it can recover toner. In this embodiment, the toner filters 125 installed in the electrostatic exhaust chamber 301 and the developing exhaust chamber 302 are filters of the same shape, made of the same material, and formed with the same size air passage area. If the toner filters 125 are the same, the number of toner filters to be kept in stock as spare consumables can be reduced compared to when they are different, thus reducing the burden of filter inventory management.

[0032] <Ozone filter> An example of an ozone filter 115 is shown in Figures 6(a) to 6(c). As shown in Figure 6(a), the ozone filter 115 has a structure that allows air to pass in the airflow direction (arrow Y direction), but prevents air from passing in the direction perpendicular to the airflow direction (arrow X direction). Examples of such structures include those with a honeycomb structure in the cross-section, as shown in Figure 6(b), and those with a cross-sectional structure similar to that of corrugated cardboard, as shown in Figure 6(c). In this shape, even if a single ozone filter 115 is installed spanning the electrostatic exhaust chamber 301 and the developing exhaust chamber 302 (see Figure 4), the airflows generated by the electrostatic exhaust fan 111 and the developing exhaust fan 121 within the duct unit 300 do not interfere with each other.

[0033] Returning to the explanation of Figure 4, the air passing through the charged exhaust chamber 301 contains more ozone than the air passing through the developing exhaust chamber 302. Therefore, ribs 162 and 163 divide the single ozone filter 115 into a first filter section 115a on the charged exhaust chamber 301 side (first duct side) and a second filter section 115b on the developing exhaust chamber 302 side (second duct side). In this embodiment, the ozone filter 115 is effectively utilized by dividing it so that the air passage area of ​​the first filter section 115a (first passage area) is larger than the air passage area of ​​the second filter section 115b (second passage area).

[0034] The area ratio between the air passage area of ​​the first filter section 115a and the air passage area of ​​the second filter section 115b is set in advance to match the different ratios of ozone generated and flow rates for each charging device. As mentioned above, the airflow rate of air Q3 is smaller than that of air Q2. For example, if the airflow ratio of air Q2 to air Q3 is "4:1", the area ratio between the first filter section 115a and the second filter section 115b is also set to "4:1". If the airflow ratio of air Q2 to air Q3 is "3:1", the area ratio between the first filter section 115a and the second filter section 115b is also set to "3:1". Ribs 162 and 163 are formed to achieve this. The area ratio between the first passage area and the second passage area is set to the first area ratio when the airflow ratio of the charging exhaust fan 111 and the developing exhaust fan 121 is the first airflow ratio, and to the second area ratio which is larger than the first area ratio when the airflow ratio is larger than the first airflow ratio.

[0035] In this way, the ribs 162 and 163 substantially divide the ozone filter 115 such that the air passage area of ​​the first filter section 115a is larger than that of the second filter section 115b. By increasing the area through which the airflow exhausted from the ozone-rich charged exhaust duct 112 passes, the ozone recovery rate can be increased. Furthermore, the amount of ozone recovered by the first filter section 115a and the amount of ozone recovered by the second filter section 115b can be made approximately the same. In other words, the ozone filter 115 can recover ozone evenly across its width. Therefore, the ozone filter 115 can be used efficiently without waste.

[0036] Furthermore, the air passage area of ​​the toner filter 125 may also be changed according to the amount of scattered toner. An example of such a case is shown in Figure 7. As shown in Figure 7, both the toner filter 125a on the electrostatic exhaust chamber 301 side and the toner filter 125b on the developer exhaust chamber 302 side are electrostatic filters as described above, and have different widths, resulting in different air passage areas. Between the air Q2 passing through the electrostatic exhaust chamber 301 and the air Q3 passing through the developer exhaust chamber 302, the air Q3 passing through the developer exhaust chamber 302 contains a larger amount of scattered toner. Therefore, the ribs 161 and ribs 162 are arranged such that the air passage area of ​​the toner filter 125b in the developer exhaust chamber 302 is larger than the air passage area of ​​the toner filter 125a in the electrostatic exhaust chamber 301.

[0037] In this case, since two types of toner filters 125a and 125b, which are consumables, will be prepared with different air passage areas, the burden of filter inventory management will increase. However, the replacement timing for the toner filter 125a on the electrostatic exhaust chamber 301 side and the toner filter 125b on the developer exhaust chamber 302 side will be approximately the same. Therefore, the toner filters 125a and 125b will be replaced at the same time, which will reduce the downtime required to stop the device for filter replacement compared to when they are replaced at different times.

[0038] Furthermore, if the electrostatic exhaust fan 111 and the developing exhaust fan 121 are shared by a single fan, it becomes difficult to independently control the airflow for ozone recovery and the airflow for toner recovery. Also, if a configuration is adopted in which one fan exhausts two airflows, and the airflow volumes of air Q2 and air Q3 are different, it is necessary to adjust the cross-sectional area of ​​the duct by changing the positions of ribs 161, 162, and 163 during product design in order to set the balance of each airflow. In this case, it is not easy to set the airflow volumes of air Q2 and air Q3 to the desired levels, and trial and error may occur during the design phase, potentially leading to a time-consuming process for positioning ribs 161, 162, and 163. In addition, the toner filter 125 experiences increased air pressure loss as it recovers toner. In a configuration where one fan exhausts two airflows, if the air pressure loss becomes large, the exhaust will be biased towards the electrostatic exhaust chamber 301, which has a lower pressure loss than the developing exhaust chamber 302. This may result in insufficient airflow for toner recovery, potentially preventing proper toner recovery by the toner filter 125. Furthermore, if one fan is shared, a large fan with high airflow capacity is required to obtain the necessary airflow for toner recovery in case of high pressure loss, but such fans are expensive. Using one large fan is more expensive than using two smaller fans. Therefore, as described above, in this embodiment, two fans, the electrostatic exhaust fan 111 and the developing exhaust fan 121, which are the same fan, are provided in the duct unit 300.

[0039] Furthermore, reducing power consumption is increasingly desirable. For example, when executing the black monochrome mode, which uses only the black image forming unit Pd to form a black toner image, the developing unit is stopped for the non-black image forming units Pa, Pb, and Pc, but the photosensitive drum rotates and charging is performed by the charging device. In other words, even when executing the black monochrome mode, the charging intake fan 101 and the charging exhaust fan 111 rotate for the non-black image forming units Pa, Pb, and Pc. If a single fan is shared, the fan with high power consumption will rotate even though no toner is scattered for non-black units, resulting in wasted power. In contrast, this embodiment provides a charging exhaust fan 111 and a developing exhaust fan 121, each with relatively low power consumption and individually controllable. By rotating only the charging exhaust fan 111 for non-black units, power consumption can be reduced.

[0040] As described above, in this embodiment, in order to miniaturize the image forming apparatus 100, the electrostatic exhaust duct 112 through which air containing ozone generated in the electrostatic device passes, and the developing exhaust duct 122 through which air containing scattered toner generated in the developing device passes, are combined into a duct unit 300. The duct unit 300 is also equipped with a toner filter 125 for recovering toner, an ozone filter 115 for recovering ozone, and two fans, an electrostatic exhaust fan 111 and a developing exhaust fan 121. The inside of the duct unit 300 is divided into an electrostatic exhaust chamber 301 and a developing exhaust chamber 302 by ribs 161, 162, and 163. Only one ozone filter 115 is installed across the duct unit 300, spanning both the electrostatic exhaust chamber 301 and the developing exhaust chamber 302. It is divided by ribs 161, 162, and 163 into a first filter section 115a on the electrostatic exhaust chamber 301 side and a second filter section 115b on the developing exhaust chamber 302 side. In this way, the ribs 161, 162, and 163 (partition members) divide the duct unit 300 into the electrostatic exhaust chamber 301 and the developing exhaust chamber 302, preventing interference between the airflows generated by the electrostatic exhaust fan 111 and the developing exhaust fan 121. Furthermore, the ribs 161, 162, and 163 (partition members) divide the single ozone filter 115. This makes it easy to adjust the airflow rate through the electrostatic exhaust chamber 301 using the electrostatic exhaust fan 111 and the airflow rate through the developing exhaust chamber 302 using the developing exhaust fan 121.

[0041] Note that the same fan can be used for both the electrostatic exhaust fan 111 and the developing exhaust fan 121. As mentioned above, since the developing exhaust duct 122 is formed with a smaller cross-sectional area than the electrostatic exhaust duct 112, if the same fan is used, the airflow will be smaller than that of the electrostatic exhaust duct 112 due to air pressure loss. Alternatively, the same variable-volume fan can be used for both the electrostatic exhaust fan 111 and the developing exhaust fan 121. Since the airflows generated by the electrostatic exhaust fan 111 and the developing exhaust fan 121 within the duct unit 300 do not interfere with each other, the rotation speeds of the electrostatic exhaust fan 111 and the developing exhaust fan 121 can be controlled independently depending on the situation to achieve the appropriate airflow for ozone and toner recovery.

[0042] Furthermore, it is preferable to use fans of the same size for the electrostatic exhaust fan 111 and the developing exhaust fan 121. If fans of different sizes are used, as shown in Figure 8(a), a complex mold shape is required to form the duct unit 300 so as to surround all four sides, which increases costs, and sealing the gaps becomes difficult, potentially leading to air leaks. In contrast, if fans of the same size are used, as shown in Figure 8(b), the duct unit 300 can be formed with a relatively simple shape, thus eliminating the need for a complex mold shape, reducing costs, and making it easier to seal the gaps, thus minimizing air leaks.

[0043] <Department Head> As shown in Figure 1, the image forming apparatus 100 of this embodiment includes a control unit 900. The control unit 900 will be described with reference to Figure 4 and Figure 9. However, although various devices such as motors and power supplies for operating the image forming apparatus 100 are connected to the control unit 900 in addition to those shown, their illustration and description are omitted here as they are not the essence of the invention.

[0044] The control unit 900 performs various controls on the image forming apparatus 100, such as image forming operations, and includes, for example, a CPU 901 (Central Processing Unit) and a memory 902. The memory 902 is composed of ROM (Read Only Memory) and RAM (Random Access Memory). The memory 902 stores various programs and data for controlling the image forming apparatus 100. The CPU 901 can execute the various programs stored in the memory 902 and can operate the image forming apparatus 100 by executing these programs. In this embodiment, the CPU 901 can execute "image forming job processing (program)" (not shown) and "filter replacement notification processing (program)" (see Figure 10, described later) stored in the memory 902. The memory 902 can also temporarily store calculation results and other data associated with the execution of various programs.

[0045] The control unit 900 is connected to the operation unit 400 via an input / output interface. The operation unit 400, although not shown in the diagram, is a touch panel equipped with a display unit capable of displaying various programs such as image forming jobs, various data input screens, and screens for notifying the replacement of ozone filters and toner filters.

[0046] The control unit 900 is further connected to the electrostatic intake fan 101, the electrostatic exhaust fan 111, and the developing exhaust fan 121 via an input / output interface. The control unit 900 drives a motor (not shown) to rotate the electrostatic intake fan 101, the electrostatic exhaust fan 111, and the developing exhaust fan 121. The control unit 900 can change the airflow by controlling the rotation speed of the electrostatic intake fan 101, the electrostatic exhaust fan 111, and the developing exhaust fan 121 according to the usage conditions. In addition, the control unit 900 can independently control the ON / OFF switching of the electrostatic intake fan 101, the electrostatic exhaust fan 111, and the developing exhaust fan 121. In other words, the control unit 900 can independently control the electrostatic intake fan 101, the electrostatic exhaust fan 111, and the developing exhaust fan 121, and can individually control the rotation start timing and rotation stop timing.

[0047] As a result, as described above, the amount of airflow Q2 generated by the electrostatic exhaust fan 111 can be made greater than the amount of airflow Q3 generated by the developing exhaust fan 121. Furthermore, it is possible to accommodate cases where independent control of the electrostatic exhaust fan 111 and the developing exhaust fan 121 is required depending on the environment in which the image forming apparatus 100 is installed. For example, if the image forming apparatus 100 is installed in a high-temperature and high-humidity environment, the grid of the electrostatic device 2a is more susceptible to corrosion due to ozone, so it is necessary to increase the airflow of the electrostatic intake fan 101 to improve the efficiency of removing ozone attached to the grid. In order to increase the airflow of the electrostatic intake fan 101, it is necessary to increase the airflow of the electrostatic exhaust fan 111 to ensure that ozone is reliably guided to the electrostatic exhaust duct 112. In contrast, the developing exhaust fan 121 does not need to have its airflow increased even if the image forming apparatus 100 is installed in a high-temperature and high-humidity environment.

[0048] Thus, even if the required airflow for ozone recovery and the airflow for collecting scattered toner differ, in this embodiment, the electrostatic exhaust fan 111 and the developer exhaust fan 121 can be controlled independently, allowing for appropriate control of the airflow volume of each airflow. Furthermore, if the maximum airflow volume generated by the electrostatic exhaust fan 111 during image forming can be made greater than the maximum airflow volume generated by the developer exhaust fan 121, the rotation start timing of the developer exhaust fan 121 may be set earlier than the rotation start timing of the electrostatic exhaust fan 111.

[0049] When an instruction to start an image forming job is given from the operation unit 400, the control unit 900 (specifically the CPU 901) executes the "image forming job processing" stored in the memory 902. Based on the execution of the "image forming job processing," the control unit 900 controls the image forming apparatus 100 and also counts the cumulative number of image-formed recording materials S (counting unit 903). In this embodiment, the control unit 900 then notifies the user of the timing to replace the ozone filter and toner filter based on the cumulative number of recording materials S that it has counted. When the cumulative number of recording materials S reaches a predetermined threshold, the control unit 900 notifies the user of the timing to replace the ozone filter and toner filter by displaying it on the operation unit 400, which acts as a notification unit. The threshold used for notifying the replacement timing is set separately for each ozone filter and toner filter and is stored in the memory 902 in advance.

[0050] <Exchange notification processing> Figure 10 shows an example of the "filter replacement notification process" performed by the control unit 900. The filter replacement notification process is started by the control unit 900 when the image forming apparatus 100 is powered on and ends when the image forming apparatus 100 is powered off.

[0051] As shown in Figure 10, the control unit 900 determines whether the cumulative number of counted recording materials S has reached a predetermined threshold (S101). If the cumulative number of counted recording materials S has reached the predetermined threshold (Yes in S101), the process proceeds to step S102. In step S102, the control unit 900 displays on the operation unit 400 that it is time to replace the ozone filter or toner filter. If the ozone filter or toner filter is replaced by a service technician or user, the control unit 900 resets the threshold used to notify the replacement timing of the replaced ozone filter or toner filter (S103). The control unit 900 also stops displaying that it is time to replace the ozone filter or toner filter (S104).

[0052] As described above, this embodiment notifies the user of the timing to replace the ozone filter and toner filter. The user or service technician can replace the ozone filter and toner filter according to the notified replacement timing. However, the lifespan of the toner filter differs between the electrostatic exhaust chamber 301 and the developing exhaust chamber 302 because the amount of toner in the developing exhaust chamber 302 is greater. Therefore, it is preferable to change the threshold for notifying the replacement timing for each filter (the cumulative number of recording materials S described above) so that the appropriate replacement timing is notified for each filter. This prevents the ozone filter and toner filter from being replaced unnecessarily.

[0053] [Other embodiments] In the embodiment described above, the toner filter 125 is shown to be located within the duct unit 300 (see Figure 3), but this is not the only possible configuration. For example, the toner filter 125 may be located within the developing exhaust duct 122.

[0054] In the embodiment described above, the electrostatic exhaust fan 111 and the developing exhaust fan 121 are arranged side by side when viewed from above, but this is not the only arrangement. For example, in a color electrophotographic apparatus, at least four image forming units Pa to Pd are arranged side by side, so the spacing between each image forming unit Pa to Pd may be small and it may not be possible to secure enough space for airflow. In that case, the electrostatic exhaust fan 111, the developing exhaust fan 121 and each duct (112, 122) can be arranged vertically to secure space for airflow.

[0055] In the above-described embodiment, an intermediate transfer type image forming apparatus 100 was explained as an example in which toner images are first transferred from each color photosensitive drum 3a to 3d to an intermediate transfer belt 20, and then secondarily transferred from the intermediate transfer belt 20 to the recording material S. However, the embodiment is not limited to this. The above-described embodiment is also applicable to a direct transfer type image forming apparatus in which toner images are directly transferred from each color photosensitive drum 3a to 3d, which carry and rotate the toner images, to the recording material S.

[0056] Furthermore, this technology can also be configured as follows. (1) An image forming apparatus for forming an image on a recording material, An image forming unit comprising: a photoreceptor that is driven to rotate; a corona charging device that charges the photoreceptor; an exposure device that forms an electrostatic latent image on the charged photoreceptor; and a developing device that develops the electrostatic latent image formed on the photoreceptor into a toner image using toner. The duct unit includes a first duct with a first air intake port formed for drawing in air containing ozone generated when the charging device charges the photoreceptor, and a second duct with a second air intake port formed for drawing in air containing toner scattered when the developing device develops the electrostatic latent image, and guides the air drawn in from the first and second air intake ports to the outside of the image forming apparatus. A first fan generates a first airflow within the first duct so that air is drawn in from the first intake port, A second fan generates a second airflow within the second duct so that air is drawn in from the second intake port, The system includes an ozone filter that is detachably provided to both the first duct and the second duct, and is positioned across the first duct and the second duct to remove ozone contained in the first airflow and the second airflow, An image forming apparatus characterized by the following features. (2) The duct unit is provided with a partition member that divides the inside of the duct unit such that the first area through which air passes to the ozone filter in the first duct is different from the second area through which air passes to the ozone filter in the second duct. The image forming apparatus according to (1) above, characterized in that (3) The airflow rate of the first fan is greater than that of the second fan. The first area through which passage is greater than the second area through which passage is greater. The image forming apparatus according to (2) above, characterized in that (4) The airflow rate of the first fan is greater than the airflow rate of the second fan. The image forming apparatus according to (1) above, characterized in that (5) It is equipped with a third fan for generating a third airflow that draws air towards the corona charging device, The airflow rate of the first fan is greater than the airflow rate of the third fan. The image forming apparatus according to any one of (1) to (4) above, characterized in that (6) A toner filter is provided that is detachably attached to the first duct and removes toner contained in the first airflow, The toner filter is located upstream of the ozone filter in the first airflow. The image forming apparatus according to any one of (1) to (5) above, characterized in that (7) A toner filter is provided that is detachably attached to the second duct and removes toner contained in the second airflow, The toner filter is located upstream of the ozone filter in the second airflow. The image forming apparatus according to any one of (1) to (6) above, characterized in that (8) The aforementioned toner filter is an electrostatic filter made of nonwoven fabric. The image forming apparatus according to (6) or (7) above, characterized in that (9) The ozone filter does not allow air to pass through in the width direction perpendicular to the first airflow, nor in the direction perpendicular to the second airflow. The image forming apparatus according to any one of (1) to (8) above, characterized in that (10) The ozone filter has ventilation holes with a honeycomb structure in cross-section. The image forming apparatus according to any one of (1) to (9) above, characterized in that (11) A counting unit that counts the cumulative number of image-formed recording materials, The system includes a notification unit that notifies the timing for replacing the ozone filter based on the cumulative number of recording materials counted by the counting unit. The image forming apparatus according to any one of (1) to (10) above, characterized in that [Explanation of symbols]

[0057] 1a(1b, 1c, 1d)...Developing device, 2a(2b, 2c, 2d)...Corona charging device (charging device), 3a(3b, 3c, 3d)...Photoreceptor (photosensitive drum), 5a(5b, 5c, 5d)...Exposure device, 100...Image forming device, 101...Third fan (charging intake fan), 111...First fan (charging exhaust fan), 112...First duct (charging exhaust duct), 115...Ozone filter, 115a...First filter section, 115b...Second filter Ruta section, 121...Second fan (developing exhaust fan), 122...Second duct (developing exhaust duct), 125...Toner filter, 161, 162, 163...Partition members (ribs), 300...Duct unit, 301a...First intake port (first communication section), 302a...Second intake port (second communication section), 400...Notification section (operation section), 900...Control section, 903...Counting section, Pa (Pb, Pc, Pd)...Image forming unit (image forming section), S...Recording material

Claims

1. An image forming apparatus for forming an image on a recording material, an image forming unit including a photosensitive member that is driven to rotate, a corona charging device that charges the photosensitive member, an exposure device that forms an electrostatic latent image on the charged photosensitive member, and a developing device that develops the electrostatic latent image formed on the photosensitive member into a toner image using toner; a duct unit including a first duct formed with a first intake port for taking in air containing ozone generated when the charging device charges the photosensitive member, and a second duct formed with a second intake port for taking in air containing toner scattered when the developing device develops an electrostatic latent image, the duct unit directing the air taken in from the first intake port and the second intake port to the outside of the image forming apparatus; a first fan that generates a first airflow in the first duct so that air is drawn in through the first air intake port; a second fan that generates a second airflow in the second duct so that air is drawn in through the second air intake; an ozone filter that is detachably provided to both the first duct and the second duct, and that is disposed across the first duct and the second duct to remove ozone contained in the first air flow and the second air flow, An image forming apparatus characterized by:

2. a partition member that partitions the inside of the duct unit so that a first air passage area with respect to the ozone filter in the first duct and a second air passage area with respect to the ozone filter in the second duct are different from each other.

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

3. The airflow rate of the first fan is greater than the airflow rate of the second fan, The first passage area is larger than the second passage area.

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

4. The airflow rate of the first fan is greater than the airflow rate of the second fan.

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

5. a third fan for generating a third airflow that draws air toward the corona charging device; The airflow rate of the first fan is greater than the airflow rate of the third fan.

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

6. a toner filter that is detachably provided in the first duct and removes toner contained in the first air flow; the toner filter is provided upstream of the ozone filter in the first air flow.

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

7. a toner filter that is detachably provided in the second duct and removes toner contained in the second air flow; the toner filter is provided upstream of the ozone filter in the second air flow.

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

8. The toner filter is an electrostatic filter made of nonwoven fabric.

7. The image forming apparatus according to claim 6, wherein the image forming apparatus is a recording medium.

9. the ozone filter does not allow air to pass in a width direction perpendicular to the first air flow and does not allow air to pass in a direction perpendicular to the direction of the second air flow; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

10. The ozone filter has ventilation holes with a honeycomb cross section.

10. The image forming apparatus according to claim 9,

11. a counting unit that counts the cumulative number of recording materials on which images have been formed; a notification unit that notifies the user when it is time to replace the ozone filter based on the cumulative number of sheets of recording material counted by the count unit, 11. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images