Image forming apparatus

Abstract

To provide an image forming device with which, in a structure having a plurality of collection containers for accommodating powder to be collected, it is possible to adjust the replacement timing of at least one collection container, as compared with the case where the amount of powder accommodated in each of the plurality of collection containers is not controlled.SOLUTION: An image forming device comprises: an image holding body; a developing device for developing a latent image formed on the image holding body into a visible image composed of powder; an intermediate transfer body; a transfer device for transferring the visible image to the intermediate transfer body; a first cleaning device for cleaning the powder remaining in the image holding body; a first collection container for accommodating the powder collected by the first cleaning device; a second cleaning device for collecting and cleaning the powder remaining in the intermediate transfer body; a second collection container for collecting the powder collected by the second cleaning device; a power feeding device for supplying a transfer bias to the transfer device; and change means for changing the transfer bias supplied from the power feeding device so that the amount accommodated in the first and the second collection containers, respectively, is adjusted when a powder image to be discarded is formed on the image holding body.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] This invention relates to an image forming apparatus.

Background Art

[0002] Patent Document 1 describes a toner supply and recovery mechanism for an electrophotographic image forming apparatus that uses a plurality of colors of toner, including waste toner buffer storage means for accumulating untransferred toner during the electrophotographic image forming process in one location, a plurality of recovered toner conveying means for conveying recovered toner from a drum cleaner section and an ITB cleaner section to the waste toner buffer storage means, and recovered toner distribution means for distributing the toner accumulated in the waste toner buffer storage means according to the new toner supply ratio, as well as an image forming apparatus using such a toner supply and recovery mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] This invention provides an image forming apparatus capable of adjusting the replacement timing of at least one recovery container in a configuration where there are a plurality of recovery containers for storing recovered powder, as compared with a case where the amounts of powder stored in the plurality of recovery containers are not controlled.

Means for Solving the Problems

[0005] This invention (1) an image carrier for holding an image, a developing device for developing a latent image formed on the image carrier into a visible image made of powder, an intermediate transfer member for temporarily conveying the visible image transferred from the image carrier, A transfer device that transfers the visible image of the image carrier to the intermediate transfer body; A first cleaning device that collects and cleans the powder remaining on the image carrier; A first recovery container that stores the powder recovered by the first cleaning device; A second cleaning device that collects and cleans the powder remaining on the intermediate transfer body; A second recovery container that stores the powder recovered by the second cleaning device; A power supply device that supplies a transfer bias to the transfer device; When a powder image to be discarded is formed on the image carrier, the transfer bias supplied from the power supply device The powder of the powder image to be discarded is Changing means for changing so that the amounts respectively stored in the first recovery container and the second recovery container are adjusted; Comprising A plurality of image forming apparatuses including the image holding member, the developing device, the transferring device, the first cleaning device, and the first recovery container are provided, and the plurality of image forming apparatuses are arranged side by side in the conveyance direction of the intermediate transfer member, and the volume of the first recovery container in one of the plurality of image forming apparatuses is configured to be larger than the volume of the first recovery container in the remaining image forming apparatuses other than the one image forming apparatus, and a conveyance path for conveying the powder recovered by the second cleaning device to the first recovery container in the one image forming apparatus, and a detection means for detecting the amount of powder stored in the first recovery container are provided, and The changing means when the detection means detects that the amount of powder stored in the first recovery container of the one image forming apparatus is less than a predetermined almost full amount close to full, Sets the transfer bias to a first transfer bias that adjusts the powder of the powder image to be discarded to be easily transferred to the intermediate transfer body; when the detection means detects that the amount of the powder is equal to or more than the predetermined almost full amount, To supply to the transfer device of the image forming apparatus provided with the first recovery container having the smallest amount of powder stored therein among the first recovery containers of the remaining image forming apparatuses excluding the one image forming apparatus, The transfer bias so that the powder of the powder image to be discarded is reversely transferred to the image holding member of the one image forming apparatus, Is an image forming device that changes to a second transfer bias to be adjusted.

[0006] This invention (2) An image carrier that holds an image; A developing device that develops a latent image formed on the image carrier into a visible image made of powder; A transfer carrier that conveys a sheet-like material for transferring the visible image of the image carrier; A transfer device that transfers the visible image to the sheet-like material conveyed by the transfer carrier; A first cleaning device that collects and cleans the powder remaining on the image carrier; A first recovery container that stores the powder recovered by the first cleaning device; a third cleaning device for recovering and cleaning the powder remaining on the transfer conveyance body, a third recovery container for storing the powder recovered by the third cleaning device, A power supply device that supplies a transfer bias to the transfer device, When a powder image to be discarded is formed on the image carrier, the transfer bias supplied from the power supply device, The powder of the powder image to be discarded is The first recovery container and the Third Changing means for changing so that the amounts respectively accommodated in the recovery containers are adjusted, Comprising, A plurality of image forming devices including the image carrier, the developing device, the transfer device, the first cleaning device, and the first recovery container are provided, and the plurality of image forming devices are arranged side by side in the conveyance direction of the intermediate transfer body, And the volume of the first recovery container in one of the plurality of image forming devices is configured to be larger than the volume of the first recovery container in the remaining image forming devices other than the one image forming device, And the Third A transport path for transporting the powder recovered by the cleaning device to the first recovery container in the one image forming device, and detection means for detecting the amount of powder accommodated in the first recovery container are provided, And the changing means, When the detection means detects that the amount of powder accommodated in the first recovery container of the one image forming device is less than a predetermined almost-full amount close to full, the transfer bias is adjusted to a first transfer bias such that the powder of the powder image to be discarded is easily transferred to the transfer carrier, When the detection means detects that the amount of the powder is equal to or more than the predetermined almost-full amount, the transfer bias supplied to the transfer device of the image forming device including the first recovery container having the smallest amount of powder accommodated among the first recovery containers of the remaining image forming devices excluding the one image forming device is adjusted to a second transfer bias such that the powder of the powder image to be discarded is reversely transferred to the image carrier of the one image forming device. It is an image forming apparatus that changes.

[0011] This invention ( 3 ) is in the image forming apparatus of the above invention (1) Or (2) In, A powder container having a supply storage section for storing the powder supplied to the developing device is provided. The first recovery container is an image forming apparatus configured as a recovery storage section provided integrally with the powder container.

Advantages of the Invention

[0018] According to the image forming apparatus of the above invention (1), in a configuration having a plurality of recovery containers for storing the recovered powder, While using the first recovery container having a relatively large volume among the plurality of first recovery containers and actually stored in the plurality of first recovery containers, corresponding to the amount of powder, Of the plurality of first recovery containers at least one replacement timing can be Efficiently adjusted.

[0019] The above invention (2) Of the image forming apparatus According to this, in a configuration having a plurality of recovery containers for storing the recovered powder, while using a first recovery container having a relatively large volume among the plurality of first recovery containers and corresponding to the amount of powder actually stored in the plurality of first recovery containers, at least one replacement timing of the plurality of first recovery containers can be efficiently adjusted.

[0020] According to the above invention (3), in a configuration having a plurality of recovery containers for storing the recovered powder, Do not control the amount of powder stored in each of the plurality of recovery containers thereof, compared to the case, Suppress the amount of powder remaining in the supply storage unit when replacing the powder container having the supply storage unit and the recovery storage unit, this can be done.

Brief Description of the Drawings

[0031]

FIG. 1

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

FIG. 11

FIG. 12

FIG. 13

FIG. 14

FIG. 15

FIG. 16

FIG. 17

FIG. 18

FIG. 19

Embodiment for Carrying out the Invention

[0032] Hereinafter, an embodiment for carrying out this invention (simply referred to as "embodiment" in this specification) will be described with reference to the drawings.

[0033] Embodiment 1. FIG. 1 and FIG. 2 are drawings showing an image forming apparatus 1 which is an example of an image forming apparatus according to Embodiment 1. FIG. 1 shows the external appearance state of the image forming apparatus 1, and FIG. 2 shows the internal configuration of the image forming apparatus 1. In the following description, the direction indicated by arrow X in the drawings is the width direction of the apparatus, the direction indicated by arrow Y is the height direction of the apparatus, and the direction indicated by arrow Z is the depth direction of the apparatus orthogonal to each of the width direction and the height direction.

[0034] <Configuration Regarding the Whole Image Forming Apparatus> The image forming apparatus 1 is an apparatus for forming a visible image composed of a developer which is an example of powder on a sheet-like object or a sheet of paper 9 which is an example of a recording medium. The image forming apparatus 1 according to Embodiment 1 is configured as a printer that forms an image as a visible image corresponding to image information input from an external connection device such as an information terminal or a personal computer, for example. As the developer, for example, a two-component developer containing non-magnetic toner and magnetic carrier is used. The image information is information related to an image such as characters, graphics, photographs, patterns, etc., for example.

[0035] As shown in FIG. 1, this image forming apparatus 1 has a housing 10 whose external appearance has a box shape. The housing 10 is composed of materials such as a support frame and an exterior panel. This housing 10 is provided with a front cover 11 that opens and closes on its front surface and a side cover 12 that opens and closes on its right side surface, and a discharge storage portion 13 for storing the sheet of paper 9 on which an image is formed and discharged is provided on its upper surface. Further, as shown in FIG. 1(B), the housing 10 is provided with a container mounting portion 14 at the portion where the side cover 12 is opened, and various replaceable containers are detachably mounted thereon.

[0036] Examples of the container include a replaceable (cartridge type) developer container 51 which is an example of a powder container that stores the supplied developer (mainly toner), a first recovery container 61 that stores the developer (mainly toner) recovered by a first cleaning device 26 described later, and a second recovery container 65 that stores the developer (mainly toner) recovered by a second cleaning device 36 described later. Among these, there are four developer containers 51Y, 51M, 51C, and 51K for the developer container 51 that respectively store four colors of toner described later. Also, for the first recovery container 61, there are four first recovery containers 61Y, 61M, 61C, and 61K that separately store the developer recovered by each of the first cleaning devices 26 in the four image forming devices 20 (Y, M, C, K) described later.

[0037] As shown in FIG. 2, the image forming apparatus 1 includes, in the internal space of the housing 10, an image forming device 20 that forms a visible image based on image information, an intermediate transfer device 30 that temporarily holds the visible image formed by the image forming device 20 and then secondarily transfers it to the paper 9, a paper feeding device 40 that stores and supplies the paper 9 to be supplied to the secondary transfer position of the intermediate transfer device 30, a fixing device 45 that fixes the visible image secondarily transferred by the intermediate transfer device 30 to the paper 9, a control device 16 that controls the operations of each device, and the like. This image forming apparatus 1 is an image forming apparatus to which a so-called intermediate transfer method is applied.

[0038] The control device 16 is a device including an arithmetic processing device, a storage element, a storage device, an input / output device, and the like. Further, the control device 16 operates based on a control program and control data stored in the storage element and the like triggered by various detection information, operation commands, etc., and controls the operations of the devices and equipment to be controlled.

[0039] The image forming device 20 is composed of four image forming devices 20Y, 20M, 20C, and 20K that respectively form four colors of visible images of yellow (Y), magenta (M), cyan (C), and black (K) dedicatedly by, for example, an electrophotographic method.

[0040] Each of the four image forming devices 20 (Y, M, C, K) has a drum-shaped photoreceptor 21 which is an example of an image holding member that is rotationally driven in the direction indicated by arrow A. Around the photoreceptor 21, devices such as a charging device 22, an exposure device 23, developing devices 24 (Y, M, C, K), a primary transfer device 25, and a first cleaning device 26 are arranged and configured. In FIG. 2, the reference numerals 21 to 26 are all shown only for the yellow (Y) image forming device 20Y, and only a part of them is shown for the image forming devices 20 (M, C, K) of other colors. Further, these image forming devices 20 (Y, M, C, K) are arranged in series along the conveyance direction (rotation direction) of the intermediate transfer device 30 (the intermediate transfer belt 31 to be described later).

[0041] Among these, the charging device 22 is a device that charges the outer peripheral surface (image forming surface) of the photoreceptor 21 to a required surface potential. The exposure device 23 is a device that forms an electrostatic latent image by performing exposure corresponding to the image signals of the color components (Y, M, C, K) generated based on the image information on the outer peripheral surface of the photoreceptor 21. The image signals are obtained through an image processing device 17 connected to the control device 16.

[0042] The developing devices 24 (Y, M, C, K) are devices that develop the electrostatic latent image formed on the outer peripheral surface of the photoreceptor 21 with a developer (toner) of a required color (Y, M, C, K) corresponding thereto to form a toner image which is a visible image.

[0043] The developing devices 24 (Y, M, C, K) differ only in that the colors of the developers they handle are different from each other, and they have the same configuration otherwise. That is, as the developing device 24K is typically shown in FIG. 3, the developing devices 24 (Y, M, C, K) include a developing roll 24b that holds the developer and supplies it to the developing area of the photoreceptor 21 facing the developing opening in a container-shaped housing 24a having a developer storage chamber and a developing opening, stirring and conveying members 24c, 24d such as a screw auger that conveys the developer accommodated in the developer storage chamber of the housing 24a while stirring it, and an adjusting member 24e that adjusts the amount (layer thickness) of the developer held on the developing roll 24b, etc.

[0044] Taking the developing device 24K as a representative example, the developing device 24 (Y, M, C, K) develops the electrostatic latent image on the photosensitive member 21 into a visible black toner image by electrostatically attaching the black toner triboelectrically charged by the agitation of the agitation and conveyance members 24c and 24d to the electrostatic latent image on the developing roll 24b.

[0045] The primary transfer device 25 is a device that transfers each color toner image to the intermediate transfer device 30 (intermediate transfer belt 31) mainly by electrostatic action. As shown in FIGS. 3 and 5, the primary transfer device 25 in the first embodiment is a contact type transfer device that uses a primary transfer roll, which is an example of a contact transfer member to which a primary transfer bias is supplied. As shown in FIG. 5, a required primary transfer bias is supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25.

[0046] The first cleaning device 26 is a device that cleans the outer peripheral surface of the photosensitive member 21 by scraping off unnecessary toner, paper powder, and other unnecessary substances adhering to the outer peripheral surface of the photosensitive member 21. The first cleaning device 26 is configured by disposing, inside the container main body 26a, a contact cleaning member 26b that scrapes off the unnecessary substances (mainly toner), and a conveying member 26c such as a screw auger that collects the unnecessary substances scraped off by the contact cleaning member 26b and conveys them to the first collection container 61 (Y, M, C, K).

[0047] In these image forming devices 20 (Y, M, C, K), the portions where the photosensitive member 21 and the primary transfer roll of the primary transfer device 25 face each other (via the intermediate transfer belt 31) become the primary transfer positions TP1 for performing the primary transfer of the toner image. Then, in the image forming devices 20 (Y, M, C, K), when an image formation is instructed from an external connection device connected to the image forming apparatus 1 and a command for an image forming operation is received by the control device 16, a toner image of any one of the four colors (Y, M, C, K) is exclusively formed on each photosensitive member 21, and the formed toner image is primarily transferred to the intermediate transfer device 30 (intermediate transfer belt 31) at each primary transfer position TP1.

[0048] The intermediate transfer device 30 is a device that transports the toner images of each color formed by the image forming device 20 (Y, M, C, K) to the position where they are secondarily transferred onto the paper 9 after holding them by primary transfer, and then secondarily transfers them onto the paper 9.

[0049] In Embodiment 1, the intermediate transfer device 30 is disposed above the image forming device 20 (Y, M, C, K) inside the housing 10. Further, as shown in FIGS. 2 and 3, this intermediate transfer device 30 includes an intermediate transfer belt 31 which is an example of an intermediate transfer member that holds the toner image transferred primarily from each photoreceptor 21 of the image forming device 20 (Y, M, C, K). The following devices are arranged around the intermediate transfer belt 31 to form the device.

[0050] The intermediate transfer belt 31 is an endless belt that can hold the toner image mainly by electrostatic action. It is supported by a plurality of support rolls 32 (for example, two support rolls 32a and 32b) arranged inside it so as to sequentially pass through each primary transfer position TP1 of the image forming device 20 (Y, M, C, K) and rotate (circumferentially move) in the direction indicated by arrow B. One of the plurality of support rolls 32a and 32b is configured as a drive roll. Also, one of the plurality of support rolls 32a and 32b is configured as a tension roll that applies tension to the intermediate transfer belt 31.

[0051] Inside the intermediate transfer belt 31, the primary transfer rolls of the primary transfer devices 25 in each image forming device 20 (Y, M, C, K) are arranged. The primary transfer device 25 is configured to rotate with the primary transfer roll pressing the intermediate transfer belt 31 against the photoreceptor 21. Also, the primary transfer device 25 is also a part of the intermediate transfer device 30.

[0052] Further, on the outer peripheral surface portion supported by the support roll 32a of the intermediate transfer belt 31, a secondary transfer device 35 is disposed which allows the sheet 9 to pass therethrough and secondarily transfers the toner image on the intermediate transfer belt 31 onto the sheet 9. The secondary transfer device 35 in the first embodiment is a contact type transfer device using a secondary transfer roll which is an example of a contact transfer member to which a secondary transfer bias is supplied. Further, the secondary transfer device 35 is configured such that the secondary transfer roll contacts and passes the sheet 9 by pressing it against the outer peripheral surface portion supported by the support roll 32a of the outer peripheral surface of the intermediate transfer belt 31. As shown in FIG. 5, a required secondary transfer bias is supplied from the power supply device 18 to the secondary transfer roll of the secondary transfer device 35.

[0053] Furthermore, around the outside of the intermediate transfer belt 31, a second cleaning device 36 is disposed which removes unnecessary substances such as unnecessary toner remaining on the outer peripheral surface of the intermediate transfer belt 31 after secondary transfer and cleans the outer peripheral surface of the intermediate transfer belt 31. As shown in FIG. 2, the second cleaning device 36 is configured by disposing, inside the container body 36a, a contact cleaning member 36b which scrapes off the unnecessary substances (mainly toner), and a conveying member 36c such as a screw auger which collects the unnecessary substances scraped off by the contact cleaning member 36b and conveys them to the second recovery container 65.

[0054] In this intermediate transfer device 30, the portion where the secondary transfer device 35 (the secondary transfer roll thereof) contacts the outer peripheral surface of the intermediate transfer belt 31 becomes the secondary transfer position TP2 where the secondary transfer of the toner image is performed. In the intermediate transfer device 30, during the image forming operation, when the toner image is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 31, the toner image is conveyed to the secondary transfer position TP2 by the rotation of the intermediate transfer belt 31 and secondarily transferred onto the sheet 9.

[0055] The paper feeding device 40 is a device configured to accommodate and supply the sheet 9 to be supplied to the secondary transfer position TP2 of the intermediate transfer device 30. The paper feeding device 40 is disposed at a position below the image forming device 20 (Y, M, C, K) inside the housing 10. This paper feeding device 40 is configured by arranging a pull-out type container 41 for loading and accommodating the paper 9, and devices such as a feeding device 42 for feeding out the paper 9 accommodated in the container 41 one by one. The feeding device 42 is composed of a pair of conveying rolls arranged on one end side of the container 41, a discharging member (not shown), and the like.

[0056] Between this paper feeding device 40 and the secondary transfer position TP2 of the intermediate transfer device 30, as shown in the figure 2 a supply conveyance path Tr1 is provided for conveying the paper 9 so as to supply it to the secondary transfer position TP2. The supply conveyance path Tr1 is configured by arranging a pair of conveying rolls 43 for sandwiching and conveying the paper 9, a guiding member 44 for securing the conveyance space of the paper 9 and guiding the conveyance of the paper 9, and the like. The paper 9 used in the image forming apparatus 1 only needs to be a recording medium such as plain paper, coated paper, or thick paper that can be conveyed inside the housing 10 and on which toner images can be transferred and fixed, and there are no particular restrictions on its material, form, etc.

[0057] The fixing device 45 is a device configured to fix the toner image secondarily transferred by the intermediate transfer device 30 onto the paper 9. The fixing device 45 is arranged at a position above the secondary transfer position TP2 of the intermediate transfer device 30 inside the housing 10. This fixing device 45 is configured by arranging devices such as a heating rotary body 46 in the form of a roll having a heating means (not shown) and a pressing rotary body 47 in the form of a roll in the internal space of a housing (not shown) provided with an inlet and an outlet for the paper 9. Further, in the fixing device 45, the portion where the heating rotary body 46 and the pressing rotary body 47 come into contact is configured as a nip portion (fixing processing portion) for performing processing such as heating and pressing to fix the toner image of the unfixed image onto the paper 9.

[0058] In the fixing device 45, during the image forming operation, the paper 9 on which the toner image has been secondarily transferred at the secondary transfer position TP2 is conveyed and passed through so as to be introduced into the nip portion. Thereby, the toner image on the paper 9 is heated and melted at the nip portion and fixed onto the paper 9.

[0059] Between this fixing device 45 and the discharge port 15 provided in the housing 10, as shown in FIG. 2 There is provided a discharge conveyance path Tr3 that conveys and discharges the sheet 9 after the fixing is completed to the discharge and storage unit 13. The discharge conveyance path Tr3 is configured by arranging a pair of discharge rolls 48 in front of the discharge port 15 and a guiding member (not shown) that secures a conveyance space for the sheet 9 and guides the conveyance of the sheet 9. During the image forming operation, the sheet 9 after the fixing by the fixing device 45 is discharged through the discharge conveyance path Tr3 to the discharge and storage unit 13 and stored therein.

[0060] The image forming apparatus 1 can form, for example, a multicolor image (full-color image) configured by combining toner images of four colors (Y, M, C, K) by operating all four image forming devices 20 (Y, M, C, K), or a monochromatic image (e.g., black-and-white image) composed of a monochromatic toner image by operating one of the four image forming devices 20 (Y, M, C, K).

[0061] <Configuration Regarding Toner Supply> In the image forming apparatus 1, since the developer (toner) is consumed and reduced in the developing process during image formation in the developing devices 24 (Y, M, C, K), the developing devices 24 (Y, M, C, K) are configured to be supplied with the toner stored in the developer containers 51 (Y, M, C, K).

[0062] Therefore, the developing devices 24 (Y, M, C, K) are provided with a receiving portion having a receiving port (not shown) for receiving the toner supplied to a portion where one end of the agitation and conveyance member 24c extends toward the container mounting portion 14 side and an opening / closing lid. In addition, as shown in FIG. 4, the container mounting portion 14 of the housing 10 is provided with a supply conveyance portion 27 (Y, M, C, K) that connects the receiving portions of the respective developing devices 24 (Y, M, C, K) and the developer containers 51 (Y, M, C, K) and conveys the supplied toner, and a drive transmission portion 28 that transmits rotational power to a discharge member (described later) disposed inside the developer containers 51 (Y, M, C, K). The supply and conveyance unit 27 (Y, M, C, K) and the drive transmission unit 28 are provided in a state of protruding from the container mounting unit 14 as shown in FIG. 4.

[0063] The supply and conveyance unit 27 (Y, M, C, K) is composed of a conveyance pipe that forms a conveyance space connecting the above receiving unit and the developer container 51 (Y, M, C, K), and a conveyance member that rotates inside the conveyance pipe at a desired time to convey toner. On the upper surface of the end portion of the supply and conveyance unit 27 (Y, M, C, K) protruding from the container mounting unit 14, a receiving port and an opening / closing lid (not shown) are provided. On the end portion of the drive transmission unit 28 protruding from the container mounting unit 14, a connecting gear (not shown) is exposed.

[0064] The developer container 51 (Y, M, C, K) is a container having a required shape, and is provided with a connecting portion having a discharge port into which the supply and conveyance unit 27 (Y, M, C, K) is inserted and connected at its lower portion. Also, a discharge member such as a screw auger is provided that rotationally drives the toner accommodated inside the container at the discharge portion to discharge a predetermined amount of toner to the supply and conveyance unit 27 (Y, M, C, K). When the developer container 51 (Y, M, C, K) is mounted on the container mounting unit 14, the supply and conveyance unit 27 (Y, M, C, K) is inserted and connected to the connecting portion, and the discharge member is connected to the drive transmission unit 28.

[0065] Further, in the developer container 51 (Y, M, C, K), the control device 16 performs control to operate the drive transmission unit 28 for a predetermined time corresponding to the detection information, so that the discharge member rotates by a predetermined amount and discharges the accommodated toner to the supply and conveyance unit 27 (Y, M, C, K) respectively. Thereby, toner is conveyed from the corresponding developer container 51 (Y, M, C, K) to the developing device 24 (Y, M, C, K) through the supply and conveyance unit 27 (Y, M, C, K) respectively and replenished in an appropriate amount. The detection information at this time is, for example, the detection information of a sensor that detects the toner amount inside the developing device 24, the detection information of a density detection toner image for control, etc.

[0066] <Configuration regarding the accommodation of recovered toner and the like> In the image forming apparatus 1, unnecessary substances (mainly toner) recovered by each first cleaning device 26 in the image forming devices 20 (Y, M, C, K) are configured to be respectively accommodated in the first recovery containers 61 (Y, M, C, K).

[0067] Therefore, the first cleaning device 26 is disposed in a first recovery conveyance unit 29 (FIG. 4) provided so that the conveyance member 26c extends so as to protrude from the first cleaning device 26 toward the container mounting portion 14 side of the housing 10. The first recovery conveyance unit 29 is provided with a discharge port and an opening / closing lid (not shown) on the lower surface portion of the end protruding from the container mounting portion 14.

[0068] The first recovery container 61 (Y, M, C, K) is a container having a required shape, and a connection portion having a recovery port into which the first recovery conveyance unit 29 is inserted and connected is provided at the upper part thereof. When the first recovery container 61 (Y, M, C, K) is mounted on the container mounting portion 14, the first recovery conveyance unit 29 is inserted and connected to the connection portion.

[0069] When the image forming device 20 is operating, unnecessary substances, mainly toner, respectively recovered by the first cleaning devices 26 are conveyed through the first recovery conveyance unit 29 and respectively accommodated in the respective containers. Furthermore, in the image forming apparatus 1, unnecessary substances (mainly toner) recovered by the second cleaning device 36 in the intermediate transfer device 30 are configured to be recovered in the second recovery container 65. Therefore, the second cleaning device 36 is disposed in a second recovery conveyance unit 37 (FIG. 4) provided so that the conveyance member 36c extends so as to protrude from the second cleaning device 36 toward the container mounting portion 14 side of the housing 10. The second recovery conveyance unit 37 is provided with a discharge port and an opening / closing lid (not shown) on the lower surface portion of the end protruding from the container mounting portion 14.

[0070] The second recovery container 65 is a container having a required shape, and a connection portion having a recovery port into which the second recovery conveyance unit 37 is inserted and connected is provided at the upper part thereof. When the second collection container 65 is attached to the container attachment portion 14, the second collection conveyance portion 37 is inserted into and connected to the connection portion thereof.

[0071] When the image forming apparatus 20 and the intermediate transfer apparatus 30 are operating, the second collection container 65 receives the unnecessary substances mainly toner collected by the second cleaning device 36 through the second collection conveyance portion 37 and stores them in the container.

[0072] Incidentally, as shown in FIG. 5, the image forming apparatus 1 includes detection means 19 for detecting the amounts of toner and the like stored in the first collection containers 61 (Y, M, C, K) and the second collection container 65, respectively.

[0073] The detection means 19 may be a sensor that actually measures the amount of toner and the like stored in the container. However, from the viewpoints of reducing the number of components and cost, it is preferably means for predicting and determining from the information on the elements related to the storage capacity. Examples of the information on the elements related to the storage capacity include information on the number of pixels and density of the toner image formed on the photoreceptor 21, and information on the number of sheets of the paper 9 for image formation. When the detection means 19 is means for predicting and determining, it can be configured as a part of the function of the control device 16. Further, in this case, the detection means 19 is adapted to predict in advance the storage capacities of the toner and the like stored in the first collection containers 61 (Y, M, C, K) and the second collection container 65 from the information on the elements related to the storage capacity.

[0074] In the image forming apparatus 1, the control device 16 determines whether or not the first collection containers 61 (Y, M, C, K) and the second collection container 65 have reached a storage capacity close to fullness at which they should be replaced based on the storage capacity which is the detection information of the detection means 19, and is configured to give a warning such as a display prompting replacement when a predetermined storage capacity to be replaced is reached.

[0075] <Configuration regarding the toner image to be discarded> In the image forming apparatus 1, it is configured to form a toner image, which is an example of a powder image to be discarded (recovered) without being transferred onto the paper 9.

[0076] The toner image to be discarded is, for example, a band-shaped toner image formed in a strip shape extending long along the rotation axis direction by development on the photoreceptor 21 to prevent curling and abnormal noise in the contact cleaning member 26b of the first cleaning device 26 of the photoreceptor 21, or a discharged toner image formed by electrostatically discharging deteriorated toner stored in the developing device 24 (Y, M, C, K) from the developing roll 24b to the photoreceptor 21. This toner image to be discarded is formed, for example, when a low-density toner image continuously formed by development with the developing device 24 (Y, M, C, K) on the photoreceptor 21. The low density means that the pixel density of the image grasped by the image processing device 17 is, for example, 1% or less. The case of being continuously formed means, for example, when the number of sheets of image formation on the paper 9 is 100 sheets or more. Note that the toner image to be discarded may include an image such as a control patch image formed on the photoreceptor 21 to obtain information for controlling the image forming operation and further transferred to the intermediate transfer belt 31.

[0077] The toner image to be discarded is formed at a time other than the time when a normal toner image to be transferred onto the paper 9 is formed. The time other than the time of forming the normal toner image includes, for example, the time between the image formed on one side of one sheet of the paper 9 and the image formed on one side of the next sheet of the paper 9. Also, the toner image to be discarded is not limited to being formed simultaneously by all of the four image forming devices 20 (Y, M, C, K), and may be formed by some of the image forming devices 20 of the image forming devices 20. In the image forming apparatus 1, as shown in FIG. 5, it is provided with determination means 5 for determining the time to form this toner image to be discarded. The determination means 5 collects information such as image density and the number of image formations from the image processing device 17 or the like, and determines the arrival of the time to form the toner image to be discarded. Further, the determination means 5 also has a counting function for counting the number of times of the time to form the toner image to be discarded.

[0078] Further, the toner image to be discarded is collected at a required ratio by the first cleaning device 26 of the photoreceptor 21 and the second cleaning device 36 of the intermediate transfer belt 31, and then collected in the first collection container 61 (Y, M, C, K) and the second collection container 65 at required ratios respectively. When forming a toner image to be discarded, no secondary transfer current is supplied to the secondary transfer roll of the secondary transfer device 35, so that the toner on the intermediate transfer belt 31 is not transferred to the secondary transfer device 35 side. The collection ratio by the first cleaning device 26 and the second cleaning device 36, and thus the ratio accommodated in the first collection container 61 (Y, M, C, K) and the second collection container 65, is adjusted by, for example, the setting content of the primary transfer current supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25. In particular, for the toner image to be discarded, the amount of toner constituting it is much larger than that of the toner image constituting a normal image, and almost 100% of the toner will be discarded. Therefore, it is necessary to also consider the amount of the toner to be collected and accommodated.

[0079] Therefore, in this image forming apparatus 1, as shown in FIG. 5, when a toner image to be discarded is formed on each photoreceptor 21 in the four image forming devices 20 (Y, M, C, K), the primary transfer currents I(Y), I(M), I(C), I(K), which are examples of the transfer bias respectively supplied from the power supply device 18 to the primary transfer rolls of the respective primary transfer devices 25, are provided with a changing means 6 that changes them so that the amounts accommodated in the first collection container 61 (Y, M, C, K) and the second collection container 65 are adjusted.

[0080] The changing means 6 changes the primary transfer current I(Y, M, C, K) supplied from the power supply device 18 when forming a toner image to be discarded one or more times based on required detection information at a stage on the way to the time of replacement when the first collection container 61 (Y, M, C, K) and the second collection container 65 reach the full capacity (including the stage before being almost full). This changing means 6 may be configured as an independent dedicated control device provided with an arithmetic processing device, a memory element, a storage device, an input / output device, etc., but as shown in FIG. 5, it is configured as a part of the control function section in the control device 16 that controls the entire image forming apparatus 1.

[0081] In Embodiment 1, since the changing means 6 includes a dedicated second collection container 65 for storing toner and the like collected by the image forming apparatus 1 using the second cleaning device 36, as shown in FIG. 6(A), at least with respect to the primary transfer current I(Y, M, C, K) when forming a toner image to be discarded, it is configured to change to a second transfer current as an example of a second transfer bias for adjusting so that the toner constituting the toner image is less likely to be transferred to the intermediate transfer belt 31 from a first transfer current as an example of a first transfer bias for adjusting so that the toner is more likely to be transferred to the intermediate transfer belt 31.

[0082] As the first transfer current at this time, when the toner is charged to a negative polarity and used, a positive primary transfer current (plus α) is set in the same manner as the primary transfer current supplied when primarily transferring a normal toner image. The value of α, which is the current value, may be approximately the same as the value of the primary transfer current in the case of a normal toner image. When this first transfer current is supplied, the toner of the toner image to be discarded formed on the photoreceptor 21 is more likely to be transferred to the intermediate transfer belt 31. In this case, the toner of the toner image to be discarded is relatively more collected by the second cleaning device 36 than by the first cleaning device 26. As a result, the collected toner and the like are relatively more stored in the second collection container 65 than in the first collection container 61(Y, M, C, K).

[0083] On the other hand, as the second transfer current, when the toner is also charged to a negative polarity and used, for example, it is set to a current (0: zero) with the supply (output) of the current turned off. As the second transfer current, it is also possible to set a negative polarity current value. When setting the second transfer current to a negative polarity, it is preferable to arrange a discharging device for discharging the outer peripheral surface of the photoreceptor 21 after primary transfer to enter the next charging step as the image forming device 20 because it becomes easier to ensure uniform charging of the photoreceptor 21. When changed to this second transfer current, the toner of the toner image to be discarded formed on the photoreceptor 21 is less likely to be transferred to the intermediate transfer belt 31 and is likely to remain on the photoreceptor 21 side. In this case, the toner of the toner image to be discarded is relatively more collected by the first cleaning device 26 than by the second cleaning device 36. As a result, the collected toner and the like are relatively more accommodated in the first collection container 61 (Y, M, C, K) than in the second collection container 65.

[0084] Further, this changing means 6 changes the primary transfer current based on the amount of toner used when forming the toner image to be discarded. Specifically, at a time or stage when the amount of toner used is small, a primary transfer current that makes it easier for the toner of the toner image to be discarded to be transferred to the intermediate transfer belt 31 is supplied. Conversely, at a time or stage when the amount of toner used increases, a primary transfer current that makes it more difficult for the toner of the toner image to be discarded to be transferred to the intermediate transfer belt 31 is supplied.

[0085] The changing means 6 in the first embodiment is configured to change the primary transfer current when the number of times of forming the toner image to be discarded reaches a predetermined value. The change of the primary transfer current is at least to change from the first transfer current to the second transfer current. The predetermined value can be set based on, for example, the ratio of the accommodation volumes of the first collection container 61 (Y, M, C, K) and the second collection container 65. Specifically, if the ratio of the accommodation volumes of the first collection container 61 (Y, M, C, K) and the second collection container 65 is a ratio of 1:N (>1), the predetermined value may be set to (N + 1) times. When the actual ratio N is a decimal value, the predetermined value is set to a value that only adopts the integer part value (a value obtained by rounding down the decimal part value). In this case, the changing means 6 obtains information on the number of times of forming the toner image to be discarded from the determination means 5.

[0086] Next, the operation when the toner image to be discarded is formed will be described.

[0087] In this image forming apparatus 1, as shown in FIGS. 5 and 7, it is determined in the determination means 5 whether it is the time to form the toner image to be discarded (step 110: S110). When it is determined in the determination means 5 that it is the time to form the toner image to be discarded, the number of times k of forming the toner image to be discarded in the determination means 5 is counted (+1) (S111).

[0088] Subsequently, it is determined in the changing means 6 whether the number of times k of forming the toner image to be discarded is less than a predetermined value (N + 1) (S112).

[0089] At this time, when it is determined that the number of times k is less than the predetermined value (N + 1), the changing means 6 selects the first transfer current for the primary transfer current I(Y,M,C,K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 when forming the toner image to be discarded (S113).

[0090] In this case, the toner image to be discarded formed on the photoreceptor 21 in the image forming device 20 (Y,M,C,K) to be created is mainly transferred to the intermediate transfer belt 31 at the primary transfer position TP1 where the first transfer current is supplied, and hardly remains on the photoreceptor 21. As a result, most of the toner of the toner image to be discarded is collected by the second cleaning device 36 of the intermediate transfer belt 31 and then conveyed to and stored in the second collection container 65, while the toner that is not primarily transferred and remains on the photoreceptor 21 is collected by the first cleaning device 26 and then conveyed to and stored in the first collection container 61(Y,M,C,K).

[0091] Also in this case, it is determined whether the forming operation of the toner image to be discarded has ended (S114). When it is determined that the forming operation has ended, the control at the time of forming the toner image to be discarded is repeated again.

[0092] On the other hand, when it is determined in step S112 that the number of times k has reached a predetermined value (N + 1) or more, for the primary transfer current I(Y,M,C,K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 when the changing means 6 forms the toner image to be discarded, a second transfer current is selected (S115). Also in this case, the count number of the number of times k of forming the toner image to be discarded in the determination means 5 is reset (S116).

[0093] In this case, for the toner image to be discarded formed on the photoreceptor 21 in the image forming device 20(Y,M,C,K) to be created, the amount of toner primarily transferred to the intermediate transfer belt 31 at the primary transfer position TP1 where the second transfer current is supplied becomes less than that in the case of the first transfer current, and the amount of toner remaining without being primarily transferred to the photoreceptor 21 increases. As a result, the toner of the toner image to be discarded is mostly stored in the first collection container 61(Y,M,C,K) after being collected by the first cleaning device 26 of the photoreceptor 21, and the amount transported and stored in the second collection container 65 after being collected by the second cleaning device 36 of the intermediate transfer belt 31 decreases.

[0094] Also in this case, it is determined whether or not the forming operation of the toner image to be discarded has ended (S114). When it is determined that the forming operation has ended, the control at the time of forming the toner image to be discarded again is repeated.

[0095] Here, for example, it is assumed that the ratio of the storage volume between the black first collection container 61K among the first collection containers 61(Y,M,C,K) and the second collection container 65 is 1:3 (=N). Also in this case, it is assumed that the black first collection container 61K among the first collection containers 61(Y,M,C,K) is configured to have a relatively larger storage volume than the other first collection containers 61(Y,M,C).

[0096] On this premise, the first transfer current (plus α) in the changing means 6 can be set to a current value such that, as shown in FIG. 6(B), the proportion of toner in the toner image to be discarded formed in the image forming apparatus 20 (Y, M, C) that is stored in the first collection container 61 (Y, M, C) is about 10%, and the proportion stored in the second collection container 65 is about 90%. Also, at this time, the first transfer current (plus α) can be set to a current value such that, as shown in FIG. 6(B), the proportion of toner in the toner image to be discarded formed in the image forming apparatus 20K that is stored in the first collection container 61K is about 20%, and the proportion stored in the second collection container 65 is about 80%. Also, in the case of the above premise, the zero (output OFF) of the second transfer current in the changing means 6 can be set to a current value condition such that, as shown in FIG. 6(B), the proportion of toner in the toner image to be discarded formed in the image forming apparatus 20 (Y, M, C, K) that is stored in the first collection container 61 (Y, M, C, K) is about 30%, and the proportion stored in the second collection container 65 is about 70%. Incidentally, in the case of this premise, the change from the first transfer current to the second transfer current by the changing means 6 is to be performed when the number of times k of forming the toner image to be discarded becomes 4 times (= N + 1).

[0097] Therefore, in this image forming apparatus 1, since the primary transfer current when forming the toner image to be discarded by the changing means 6 is controlled to be changed, the proportion of the toner in the toner image to be discarded that is stored will be changed between the first collection container 61 (Y, M, C, K) and the second collection container 65. As a result, the replacement timing of at least one of the first collection container 61 (Y, M, C, K) and the second collection container 65 is adjusted.

[0098] When changing the primary transfer current from the first transfer current to the second transfer current as in the configuration example of the above-described changing means 6, since the ratio of the toner of the toner image to be discarded accommodated in the second recovery container 65 is reduced halfway, compared with the case where the change of the primary transfer current is not performed, the replacement timing of the second recovery container 65 can be delayed. In other words, in this case, the replacement timing of the first recovery container 61 (Y, M, C, K) will be slightly advanced compared with the case where the change of the primary transfer current is not performed.

[0099] For reference, when configured to adopt only the first transfer current adopted by the above-described changing means 6 and not to change to the second transfer current, since the ratio of the toner of the toner image to be discarded accommodated does not change between the first recovery container 61 (Y, M, C, K) and the second recovery container 65, the replacement timing of the first recovery container 61 (Y, M, C, K) and the second recovery container 65 is not adjusted. As a result, in this case, since the accommodation ratio of the second recovery container 65 remains high, compared with the case where the above change (change from the first transfer current to the second transfer current) is performed, the replacement timing of the second recovery container 65 will be encountered earlier.

[0100] <Modification Example of Embodiment 1> In the image forming apparatus 1 according to Embodiment 1, as the change content of the changing means 6, the change content as shown in FIGS. 8 and 9 may be applied.

[0101] The change content of the changing means 6 in this modification example is that when the detection means 19 for detecting the amounts of toner and the like accommodated in the first recovery container 61 (Y, M, C, K) and the second recovery container 65 detects a predetermined amount slightly less than full, the transfer current is changed. The amount slightly less than full can be arbitrarily set, but for example, it is set to 80% of the full amount.

[0102] The changing means 6 of the modification example shown in FIGS. 8 and 9 is Judging as shown in FIG. 9, change the transfer bias .

[0103] Further, the changing means 6 of this modification changes the primary transfer current I(Y,M,C,K) from the first transfer current to the second transfer current when the detecting means 19 detects a predetermined amount before fullness that is close to fullness, and applies a transfer current of zero (output OFF) that is not supplied to the primary transfer device 25 as the second transfer current (FIG. 8(A)).

[0104] Next, the operation when a toner image to be discarded is formed in the image forming apparatus 1 employing the changing means 6 of this modification will be described.

[0105] In this image forming apparatus 1, as shown in FIG. 9, it is determined in the determination means 5 whether it is the timing to form a toner image to be discarded (S120). When it is determined in the determination means 5 that it is the timing to form a toner image to be discarded, the changing means 6 reads the detection information of the storage capacity S 2 of the second collection container 65 from the detection means 19 (S121).

[0106] Subsequently, in the changing means 6, it is determined whether the storage capacity S 2 of the second collection container 65 is less than the amount before fullness (S122).

[0107] At this time, if it is determined that the storage capacity S 2 of the second collection container 65 is less than the amount before fullness, the changing means 6 selects the first transfer current as the primary transfer current I(Y,M,C,K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 when forming the toner image to be discarded (S123).

[0108] In this case, the toner image to be discarded formed on the photoreceptor 21 in the image forming apparatus 20 (Y, M, C, K) to be created is mostly primary-transferred to the intermediate transfer belt 31 at the primary transfer position TP1 where the first transfer current is supplied, and hardly remains on the photoreceptor 21. As a result, most of the toner of the toner image to be discarded is conveyed to and stored in the second collection container 65 after being collected by the second cleaning device 36 of the intermediate transfer belt 31. Note that the toner remaining on the photoreceptor 21 without being primary-transferred to the intermediate transfer belt 31 is conveyed to and stored in the first collection container 61 (Y, M, C, K) after being collected by the first cleaning device 26.

[0109] Also in this case, it is determined whether or not the forming operation of the toner image to be discarded has ended (S124). When it is determined that the forming operation has ended, the control at the time of forming the toner image to be discarded again is repeated.

[0110] On the other hand, when it is determined in step 122 (S122) that the storage capacity S 2 of the second collection container 65 has reached a level equal to or more than a level just before being full, the changing means 6 selects to switch the primary transfer current I (Y, M, C, K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 to the second transfer current when forming the toner image to be discarded (S125). In this case, as the second transfer current of the primary transfer current I (Y, M, C, K), a zero transfer current that is not output as shown in FIG. 8(A) is applied to all of them.

[0111] In this case, the toner image to be discarded formed on the photoconductor 21 of the imaging device 20 (Y, M, C, K) to be created is primarily transferred to the intermediate transfer belt 31 at the primary transfer position TP1 where the second transfer current is supplied, and the amount of toner is generally less than that in the case of the first transfer current. As a result, the amount of toner of the toner image to be discarded that is primarily transferred to the intermediate transfer belt 31 and collected by the second cleaning device 36 is reduced and stored in the second collection container 65. On the other hand, the amount of toner of the toner image to be discarded in the imaging device 20 (Y, M, C, K) that is collected by each first cleaning device 26 is increased compared to the case where the first transfer current is supplied, and each of the collected toners is stored in a larger amount in the corresponding first collection container 61 (Y, M, C, K).

[0112] Also in this case, it is determined whether the operation of forming the toner image to be discarded is completed (S124), and if it is determined that the operation of forming the toner image to be discarded is completed, the control for forming the toner image to be discarded is repeated again. Incidentally, after this, in step 122, the capacity S of the second collection container 65 is 2 is always determined to be equal to or greater than the pre-full amount, the change unit 6 continues to select the second transfer current. As a result, the control operation at this time continues until any of the first collection containers 61 (Y, M, C, K) becomes full or reaches the pre-full amount.

[0113] Here, for example, it is assumed that the ratio of the storage volume of the black first collection container 61K among the first collection containers 61 (Y, M, C, K) to the second collection container 65 is configured to be 1:3 (=N), etc., and that the storage volume of the black first collection container 61K among the first collection containers 61 (Y, M, C, K) is configured to be larger (for example, 1.5 times) than the other first collection containers 61 (Y, M, C).

[0114] On the premise of this configuration content, the first transfer current (plus α) in the changing means 6 of the modification example can be set to a current value such that, as shown in FIG. 8(B), the proportion of the toner of the toner image to be discarded formed on the image forming device 20 (Y, M, C) that is stored in the first collection container 61 (Y, M, C) is about 10%, and the proportion of the toner stored in the second collection container 65 is about 90%. Also, at this time, the first transfer current (plus α) supplied to the primary transfer device 25 in one image forming device 20K can be set to a current value such that, as shown in FIG. 8(B), the proportion of the toner of the toner image to be discarded formed on the image forming device 20K that is stored in the first collection container 61K is about 20%, and the proportion of the toner stored in the second collection container 65 is about 80%. As a result, the toner of the toner image to be discarded is mostly stored in the second collection container 65. Also, on the premise of the above configuration content, the second transfer current (output OFF) in the changing means 6 of the modification example is a transfer current that decreases so that the proportion of the toner stored in the second collection container 65 when it is almost full becomes about 70%, as shown in FIG. 8(B), and the proportion of the toner of the toner image to be discarded formed on the image forming device 20 (Y, M, C, K) that is stored in the first collection container 61 (Y, M, C, K) can be set to a condition where the proportion is about 30% for all.

[0115] Therefore, also in the image forming apparatus 1 adopting the changing means 6 of this modification example, since the primary transfer current when forming the toner image to be discarded is controlled to be changed by the changing means 6, the proportion of the toner of the toner image to be discarded that is stored is changed between the first collection container 61 (Y, M, C, K) and the second collection container 65. As a result, at least one replacement timing of the first collection container 61 (Y, M, C, K) and the second collection container 65 is adjusted. Particularly in this case, using the second collection container 65 with the largest storage volume and the first collection container 61K among the plurality of first collection containers 61 (Y, M, C, K) with a relatively large storage volume, at least one (actually the first collection container 61 (Y, M, C, K)) replacement timing of the second collection container 65 and the plurality of first collection containers 61 (Y, M, C, K) is efficiently adjusted.

[0116] In Embodiment 1, instead of changing the primary transfer current when the number of times of forming the toner image to be discarded by the changing means 6 reaches a predetermined value, for example, the primary transfer current may be changed based on information predicting the amount of toner used when forming the toner image to be discarded.

[0117] Regarding the second transfer current in the changing means 6 of the above modification, it may be a transfer current that causes reverse transfer of toner to the photoreceptor 21 in one image forming apparatus 20K. As the second transfer current at this time, for example, when the toner is charged and used with a negative polarity, a negative polarity current value may be applied. When such a second transfer current is adopted, for example, in addition to being able to collect most of the toner to be discarded formed on the photoreceptor 21 in one image forming apparatus 20K by the first cleaning device 26, among the toner to be discarded formed on each photoreceptor 21 in the remaining image forming apparatuses 20 (Y, M, C), the portion of the toner that has been primarily transferred to the intermediate transfer belt 31 can be reversely transferred to the photoreceptor 21 in the image forming apparatus 20K arranged downstream of the conveyance direction (rotation direction B) of the intermediate transfer belt 31 compared to the remaining image forming apparatuses 20 (Y, M, C), and can also be collected by the first cleaning device 26 on that photoreceptor 21.

[0118] Furthermore, the changing means 6 of the above modification is the storage capacity S of the second collection container 65 2 After reaching a value just before being full, only the primary transfer current supplied to one or more of the primary transfer devices 25 of the image forming apparatuses 20 (Y, M, C, K) having the first collection containers 61 (Y, M, C, K) whose storage capacities have not reached the value just before being full among the first collection containers 61 (Y, M, C, K) may be changed to a second transfer current consisting of a zero current value or a negative current value. When this configuration is adopted, the first collection container 61 with a large remaining capacity of the storage capacity is effectively utilized, and the replacement timing of at least one of the second collection container 65 and the plurality of first collection containers 61 (Y, M, C, K) (actually the first collection containers 61 (Y, M, C, K)) is efficiently adjusted.

[0119] Embodiment 2. Figures 10 and 11 show an image forming apparatus 1B, which is another example of the image forming apparatus according to Embodiment 2. The image forming apparatus 1B according to Embodiment 2 is different from the image forming apparatus 1 according to Embodiment 1 only in that it does not include a second recovery container 65 for recovering unnecessary substances such as toner recovered by the second cleaning device 36 of the intermediate transfer belt 31, and it includes a modification means 6B whose modification content is different from that of the modification means 6 in Embodiment 1, and has the same configuration as the image forming apparatus 1 according to Embodiment 1.

[0120] As shown in FIGS. 10 and 11, this image forming apparatus 1B does not include a second recovery container 65 (FIGS. 4 and 5) for accommodating unnecessary substances such as toner recovered by the second cleaning device 36. Instead, in the image forming apparatus 1B, as shown in FIGS. 11 and 12, among the first recovery containers 61 (Y, M, C, K) in the plurality of image forming devices 20 (Y, M, C, K), the accommodation volume of the black first recovery container 61K in one of the image forming devices 20K is configured to be larger than that of the other first recovery containers 61 (Y, M, C) in the remaining image forming devices 20 (Y, M, C), and unnecessary substances such as toner recovered by the second cleaning device 36 are accommodated in the black first recovery container 61K. Also, due to this configuration, in the image forming apparatus 1B, as a recovery conveyance unit 37 for conveying unnecessary substances such as toner recovered by the second cleaning device 36, a second recovery conveyance unit 37B configured in terms of position, shape, etc. that can be connected to the connection part of the black first recovery container 61K is adopted as shown in FIG. 12.

[0121] In addition, since the changing means 6B in the second embodiment does not include a dedicated second recovery container 65 for storing the toner and the like recovered by the image forming apparatus 1B using the second cleaning device 36, and is configured to use a single first recovery container 61K as the second recovery container, as shown in FIG. 13(A), at least with respect to the transfer current, a first transfer current is adjusted so that the toner of the toner image to be discarded is less likely to be transferred to the intermediate transfer belt 31, and is changed to a second transfer current that is adjusted to be reversely transferred to at least one of the photoreceptors 21 in the remaining image forming devices 20 (Y, M, C). The at least one device is, for example, an image forming device 20 provided with a first recovery container 61 having a sufficient remaining capacity selected.

[0122] As the first transfer current at this time, as shown in FIG. 13(A), when the toner is charged to a negative polarity and used, a positive primary transfer current (plus β) is set in the same manner as the primary transfer current supplied when a normal toner image is primarily transferred. The current value β is smaller than the value of the primary transfer current in the case of a normal toner image. That is, the current value β is set to be smaller than the current value α of the first transfer current in the first embodiment (β < α), making it difficult for the toner on the photoreceptor 21 to be primarily transferred to the intermediate transfer belt 31. Note that this plus β may be set to the same value as the current value α. On the other hand, the minus β is set to a value different from the current value α.

[0123] When this first transfer current is supplied, the toner of the toner image to be discarded formed on the photoreceptor 21 becomes less likely to be transferred to the intermediate transfer belt 31. In this case, the toner of the toner image to be discarded is relatively more recovered by the first cleaning device 26 than by the second cleaning device 36. As a result, the recovered toner and the like are respectively stored in the first recovery containers 61 (Y, M, C, K). At this time, the black first recovery container 61K also stores the toner and the like recovered by the second cleaning device 36.

[0124] As for the second transfer current on one side, when the toner is also used with a negative charge, as shown in Fig. 13(A), the storage capacity S of the toner stored in the first collection container 61 (Y, M, C) in the remaining image forming devices 20 (Y, M, C). 1 The transfer current is set such that the toner is reversely transferred only to the photoreceptor 21 in the image forming device 20 equipped with the first collection container 61 having the smallest storage capacity among the first collection containers 61 (Y, M, C). In the second embodiment, for example, it is assumed that the first collection container 61 with the smallest storage capacity is the yellow first collection container 61Y. When setting this negative second transfer current, it is preferable to arrange a charge elimination device for eliminating the charge on the outer peripheral surface of the photoreceptor 21 after the primary transfer before entering the next charging step as the image forming device 20, because it becomes easier to ensure uniform charging of the photoreceptor 21 and other reasons.

[0125] When changed to this second transfer current, the toner of the toner image to be discarded formed on the photoreceptor 21 is less likely to be transferred from the photoreceptor 21 to the intermediate transfer belt 31 in the image forming devices 20 (M, C, K) and is likely to remain on the photoreceptor 21 side. On the other hand, in the yellow image forming device 20Y, the toner is reversely transferred from the intermediate transfer belt 31 to the photoreceptor 21. In this case, although the toner that has been primarily transferred exists on the intermediate transfer belt 31 in the image forming devices 20 (M, C, K), that toner is also reversely transferred from the intermediate transfer belt 31 to the photoreceptor 21 in the yellow image forming device 20Y. As a result, the toner of the toner image to be discarded is collected more by the first cleaning device 26 in the yellow image forming device 20Y, and the toner that has been primarily transferred from the photoreceptor 21 to the intermediate transfer belt 31 in the image forming devices 20 (M, C, K) of other colors is also reversely transferred to the photoreceptor 21 in the yellow image forming device 20Y and collected by the first cleaning device 26. As a result of the above, the collected toner and the like are relatively more accommodated in the first collection container 61Y in the yellow image forming device 20Y.

[0126] Next, the operation when a toner image to be discarded is formed in the image forming apparatus 1 adopting the changing means 6B in the second embodiment will be described.

[0127] In this image forming apparatus 1, as shown in FIG. 14, it is determined whether or not it is the time to form the toner image to be discarded in the determination means 5 (S130). When it is determined in the determination means 5 that it is the time to form the toner image to be discarded, the changing means 6B reads the detection information of each storage capacity S of the first collection containers 61 (Y, M, C, K) from the detection means 19 1 (S131).

[0128] Subsequently, in the changing means 6B, it is determined whether or not the storage capacity S of the black first collection container 61K having a relatively large storage volume is less than the amount before being full (S132). 1k At this time, when it is determined that the storage capacity S1k of the black first collection container 61K is less than the amount before being full, the changing means 6B selects the first transfer current as the primary transfer current I (Y, M, C, K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 when forming the toner image to be discarded (S133).

[0129] In this case, most of the toner image to be discarded formed on the photoreceptor 21 in the image forming device 20 (Y, M, C, K) to be created remains on the photoreceptor 21 and is transferred to the intermediate transfer belt 31 to such an extent. As a result, most of the toner of the toner image to be discarded Of the toner is collected by the first cleaning device 26 of each photoreceptor 21 and then stored in each first collection container 61 (Y, M, C, K). On the other hand, the toner primarily transferred to the intermediate transfer belt 31 is collected by the second cleaning device 36 and then transferred through the second collection conveyance unit 37B to the black first collection container 61K and stored. A little of that toner intermediate transfer belt 31 To one is transferred to the next level. As a result, most of the toner of the toner image to be discarded Of the toner is collected by the first cleaning device 26 of each photoreceptor 21 and then stored in each first collection container 61 (Y, M, C, K). On the other hand, the toner primarily transferred to the intermediate transfer belt 31 is collected by the second cleaning device 36 and then transferred through the second collection conveyance unit 37B to the black first collection container 61K and stored.

[0130] Also in this case, it is determined whether or not the forming operation of the toner image to be discarded has ended (S134). When it is determined that the forming operation has ended, the control at the time of forming the toner image to be discarded is repeated again.

[0131] On the other hand, when it is determined in step 132 (S132) that the storage capacity S of the black first collection container 61K has reached a level just before being full, the changing means 6B selects to switch the primary transfer current I(Y, M, C, K) supplied from the power supply device 18 to the primary transfer roll of the primary transfer device 25 to the second transfer current when forming the toner image to be discarded (S135). 1k At this time, only the primary transfer current IY supplied to the primary transfer device 25 in the yellow image forming device 20Y is switched to the second transfer current of minus β. Also, for the primary transfer currents supplied to the primary transfer device 25 in the remaining image forming devices 20 (M, C, K), the same plus β as the first transfer current continues to be applied as the second transfer current.

[0132] In this case, the toner image to be discarded formed by the image forming device 20 (Y, M, C, K) to be created is less likely to be primarily transferred to the intermediate transfer belt 31 while remaining on the photoreceptor 21 in the image forming devices 20 (M, C, K). On the other hand, in the yellow image forming device 20Y, reverse transfer of toner from the intermediate transfer belt 31 to the photoreceptor 21 also occurs, so the toner on the intermediate transfer belt 31 adheres to the photoreceptor 21 due to reverse transfer and the amount relatively increases. As a result, the amount of toner of the toner image to be discarded collected by the first cleaning device 26 in the yellow image forming device 20Y and stored in the first collection container 61Y increases. On the other hand, in the black first collection container 61K determined to be at a level just before being full, the amount of toner remaining on the intermediate transfer belt 31 and collected by the second cleaning device 36 relatively decreases, so the amount stored also decreases compared to the case of the first transfer current.

[0133] Also in this case, it is determined whether or not the formation operation of the toner image to be discarded has ended (S134). When it is determined that the formation operation has ended, the control at the time of forming the toner image to be discarded is repeated again. Incidentally, after this, in step 132, the storage capacity S of the black first collection container 61K 1kSince it is always determined that the amount is equal to or greater than the amount just before being full, the changing means 6B will continue to select the second transfer current. As a result, the control operation at this time is temporarily the storage capacity S of the first collection container 61Y of yellow color 1Y This is continued until it reaches the amount just before being full. After that, the changing means 6B changes the primary transfer current in the image forming apparatuses 20M and 20C having the first collection containers 61M and 61C of magenta or cyan colors, which have the smallest storage capacity, to the second transfer current (minus β) at which reverse transfer occurs.

[0134] In the second embodiment, as shown in FIG. 13(B), the first transfer current in the changing means 6B is such that the proportion of the toner of the waste toner image formed on the image forming apparatuses 20(Y,M,C,K) stored in the first collection container 61(Y,M,C,K) becomes about 10%, and the proportion of the toner stored in the black first collection container 61K also includes the toner recovered by the second cleaning device 36 and finally becomes about 30%. By setting the first transfer current in this way, the toner of the waste toner image is most stored in the black first collection container 61K. Also in the second embodiment, as shown in FIG. 13(B), the second transfer current in the changing means 6B is such that the proportion of the storage capacity S detected by the detecting means 19 stored in the yellow first collection container 61Y having the smallest amount increases to about 70%, while the proportion of the storage capacity of the black first collection container 61K that has reached the amount just before being full decreases to about 10%. It can be set to the condition of the current value of the transfer current. 2 Therefore, also in the image forming apparatus 1B adopting this changing means 6B, since the primary transfer current when forming the waste toner image is controlled to be changed by the changing means 6B, the proportion of the toner of the waste toner image stored is changed among the first collection containers 61(Y,M,C,K). As a result, at least one of the plurality of first collection containers 61(Y,M,C,K) is efficiently adjusted in terms of the replacement timing by using the yellow first collection container 61Y having the smallest amount of stored toner.

[0135] ​Particularly in this case, the replacement timing of the black first collection container 61K with the largest accommodation volume can be delayed slightly compared to the case where the primary transfer current is not changed by the changing means 6B.

[0136] Embodiment 3. FIG. 15 shows an image forming apparatus 1C which is another example of the image forming apparatus according to Embodiment 3. The image forming apparatus 1C according to Embodiment 3 is different from the image forming apparatus 1 according to Embodiment 1 only in that it adopts a direct transfer method of directly transferring a toner image onto a sheet of paper 9 which is an example of a so-called sheet-like material, instead of the intermediate transfer method of the image forming apparatus 1 according to Embodiment 1, and has the same configuration as the image forming apparatus 1 according to Embodiment 1.

[0137] As shown in FIG. 15, the image forming apparatus 1C includes, in the internal space of the housing 10, an image forming device 20 for forming a visible image based on image information, a transfer conveyance device 70 for conveying the sheet of paper 9 so as to transfer a toner image which is an example of the visible image formed by the image forming device 20, a paper feeding device 40 for accommodating and supplying the sheet of paper 9 to be supplied to the transfer conveyance device 70, a fixing device 45 for fixing the visible image conveyed and transferred by the transfer conveyance device 70 onto the sheet of paper 9, a control device 16 for controlling the operations of each device, and the like. The image forming device 20, the paper feeding device 40, the fixing device 45, and the control device 16 in this image forming apparatus 1C have substantially the same configuration as the image forming device 20, the paper feeding device 40, the fixing device 45, and the control device 16 in Embodiment 1. The same reference numerals are given to the corresponding common parts, and the description thereof will be omitted except when necessary.

[0138] As shown in FIG. 15, the transfer conveyance device 70 in this image forming apparatus 1C includes a transfer conveyance belt 71 which is an example of a transfer conveyance body for conveying the sheet of paper 9 so as to transfer the toner image formed by the image forming device 20, and devices such as the following paper pressing member 73, paper peeling member 74, transfer device 75, and third cleaning device 76 are arranged around the transfer conveyance belt 71.

[0139] The transfer conveyance belt 71 is an endless belt that can hold the sheet 9 by electrostatic force or the like. Also, similar to the case of the intermediate transfer belt 31, the transfer conveyance belt 71 is supported by a plurality of support rolls 72 (for example, two support rolls 72a and 72b) arranged inside it so as to sequentially pass through each transfer position TP (to be described later) of the image forming apparatus 20 (Y, M, C, K) and rotate (circumferentially move) in the direction indicated by arrow B. One of the plurality of support rolls 72a and 72b is configured as a drive roll. Further, the transfer conveyance belt 71 can also transfer toner.

[0140] The sheet pressing member 73 is a member that presses the sheet 9 conveyed and supplied from the sheet feeding device 40 against the outer peripheral surface of the transfer conveyance belt 71, and is arranged in contact with a portion of the outer peripheral surface supported by the support roll 72b of the transfer conveyance belt 71. As the sheet pressing member 73, a roll-shaped member that can be driven to rotate in contact with the outer peripheral surface of the transfer conveyance belt 71 is used. In the supply conveyance path Tr1, for example, a pair of two conveyance rolls 43a and 43b are arranged. The sheet peeling member 74 is a member that assists the movement when the sheet 9 peels off from the outer peripheral surface of the transfer conveyance belt 71, and is arranged in the vicinity of the outer peripheral surface supported by the support roll 72a of the transfer conveyance belt 71.

[0141] The transfer device 75 is a device that transfers the toner images of each color formed on each photoreceptor 21 in the image forming apparatus 20 (Y, M, C, K) mainly by an electrostatic action to the sheet 9 conveyed by the transfer conveyance belt 71. The transfer device 75 is configured substantially the same as the primary transfer device 25 in the first embodiment or the like, and a transfer roll, which is an example of a contact transfer member, is arranged inside the transfer conveyance belt 71 so as to be driven to rotate while pressing the transfer conveyance belt 71 against each photoreceptor 21 in the image forming apparatus 20 (Y, M, C, K). Also, the transfer device 75 is also a part of the image forming apparatus 20 (Y, M, C, K).

[0142] Further, the third cleaning device 76 is a device that removes unnecessary substances such as unnecessary toner remaining on the outer peripheral surface of the transfer conveyance belt 71 after transfer and cleans the outer peripheral surface of the transfer conveyance belt 71, and is disposed below the outer peripheral surface of the portion supported by the support roll 72a of the transfer conveyance belt 71. As shown in FIG. 15, the third cleaning device 76 is configured by disposing, inside a container body 76a, a contact cleaning member 76b that scrapes off the unnecessary substances (mainly toner), and a conveyance member 76c such as a screw auger that collects the unnecessary substances scraped off by the contact cleaning member 76b and conveys them to a third collection container 67 described later.

[0143] In this transfer conveyance device 70, each part where each photoreceptor 21 in the image forming device 20 (Y, M, C, K) and the transfer roll of the transfer device 75 face each other (via the transfer conveyance belt 71) becomes a transfer position TP where the toner image is transferred.

[0144] Then, when the image forming apparatus 1C is instructed to form an image from an external connection device connected to the image forming apparatus 1 and receives a command for an image forming operation by the control device 16, in the image forming device 20 (Y, M, C, K), a toner image of any one of the four colors (Y, M, C, K) is specifically formed on each photoreceptor 21. On the other hand, the sheet 9 supplied from the sheet feeding device 40 through the supply conveyance path Tr1 is held while being assisted by the pressing force of the sheet pressing member 73 on the transfer conveyance belt 71 in the transfer conveyance device 70 and is conveyed so as to pass through the transfer position TP. Thereby, the toner images formed on the respective photoreceptors 21 in the image forming device 20 (Y, M, C, K) are directly transferred to the sheet 9 held by the transfer conveyance belt 71 at each transfer position TP, respectively.

[0145] Further, in the image forming apparatus 1C, during the image forming operation, the sheet 9 on which the toner image has been transferred at the transfer position TP is peeled off from the transfer conveyance belt 71 while receiving the peeling assistance of the sheet peeling member 74 and then introduced into and passed through the nip portion in the fixing device 45, whereby the toner image is fixed on the sheet 9. Finally, the fixed sheet 9 is discharged through the discharge conveyance path Tr3 and stored in the discharge storage portion 13.

[0146] Furthermore, the housing 10 of the image forming apparatus 1C is provided with a container mounting portion 14 to which a replaceable container is detachably mounted at a portion where the side cover 12 is opened, similar to the image forming apparatus 1 according to the first embodiment (see FIGS. 1(B) and 4). As shown in FIG. 16, the replaceable container is a third recovery container 67 that houses developer containers 51Y, 51M, 51C, 51K, first recovery containers 61Y, 61M, 61C, 61K, and developer (mainly toner) recovered by the third cleaning device 76. In the image forming apparatus 1C, a third recovery conveyance path 77 is provided for conveying toner and the like recovered by the third cleaning device 76 to the third recovery container 67. One end of the third recovery conveyance path 77 is also provided in a state of protruding into the container mounting portion 14, and the protruding end portion (connection portion) is connected to the third recovery container 67.

[0147] Also, in the image forming apparatus 1C, similar to the case of the image forming apparatus 1 according to the first embodiment, it is configured to form a toner image, which is an example of a powder image to be discarded (recovered) without being transferred onto the paper 9. Further, in the image forming apparatus 1C, as shown in FIG. 16, when a toner image to be discarded is formed on each photosensitive member 21 in the four image forming devices 20 (Y, M, C, K), transfer currents I(Y), I(M), I(C), I(K) supplied from the power supply device 18 to the primary transfer rolls of the respective transfer devices 75 are changed by a changing means 6 so that the amounts stored in the first recovery containers 61 (Y, M, C, K) and the third recovery container 67 are adjusted.

[0148] This changing means 6 has substantially the same configuration as the changing means 6 in the first embodiment. In the modification means 6 in the third embodiment, since the image forming apparatus 1C includes a dedicated third collection container 67 for storing the toner and the like collected by the third cleaning device 76, at least with respect to the primary transfer current I(Y,M,C,K) when forming the toner image to be discarded, a first transfer current is adjusted so that the toner constituting the toner image is easily transferred to the transfer conveyance belt 71, and it is configured to change to a second transfer current that adjusts so that the toner of the toner image is less likely to be transferred to the transfer conveyance belt 71 (see Fig. 6(A)). Incidentally, the primary transfer current in Fig. 6(A) may be read as the transfer current. Also, plus α is a configuration example when the toner is charged to a negative polarity for use. Further, the value of plus α may be changed to a value suitable for direct transfer.

[0149] Also, the image forming apparatus 1C adopting the modification means 6 in the third embodiment is configured such that the operation when forming the toner image to be discarded is also substantially the same as the operation of the image forming apparatus 1 according to the first embodiment (Figs. 6(A) and 7).

[0150] Therefore, also in this image forming apparatus 1C, since the transfer current when forming the toner image to be discarded is controlled to be changed by the modification means 6, the ratio of storing the toner of the toner image to be discarded is changed between the first collection container 61(Y,M,C,K) and the third collection container 67. As a result, the replacement timing of at least one of the first collection container 61(Y,M,C,K) and the third collection container 67 is adjusted.

[0151] That is, also in this image forming apparatus 1C, when changing the transfer current supplied to the transfer device 75 from the first transfer current to the second transfer current by the modification means 6, the ratio of storing the toner of the toner image to be discarded in the third collection container 67 is reduced halfway (see Fig. 6(B)). Therefore, compared with the case where the change of the transfer current is not performed, the replacement timing of the third collection container 67 can be delayed. In other words, in this case, the replacement timing of the first collection container 61(Y,M,C,K) is slightly advanced compared with the case where the change of the transfer current is not performed.

[0152] <Modification Example of Embodiment 3> In the image forming apparatus 1C according to Embodiment 3, as the modification content of the changing means 6, the modification content as shown in FIGS. 8 and 9 may be applied.

[0153] The modification content in the changing means 6 of this modification example is substantially the same as the configuration of the changing means 6 of the modification example in the image forming apparatus 1 according to Embodiment 1. That is, the modification content is such that when the detecting means 19 for detecting the amount of toner or the like stored in the first collection container 61 (Y, M, C, K) and the third collection container 67 detects a predetermined almost-full amount close to full, the transfer current is changed.

[0154] The changing means 6 of this modification example is the same as that in Embodiment 1 Of the modification example of in the same manner as the case Judging as shown in FIG. 9, change the transfer bias 。

[0155] Also, in the changing means 6 of this modification example, for example, when the detecting means 19 detects a predetermined almost-full amount close to full, the transfer current I (Y, M, C, K) is changed from the first transfer current to the second transfer current, and a zero transfer current that is not supplied to the transfer device 75 is applied as the second transfer current (see FIG. 8(A)). Further, in the changing means 6 of this modification example, from the viewpoint of making the accommodation ratio of the third collection container 67 larger than that of any of the first collection containers 61 (Y, M, C, K) as the first transfer current, a current value of positive polarity (plus α) is applied, and the second transfer current of the remaining image forming devices 20 (Y, M, C) among the second transfer currents is 0V (output OFF) set as such (see FIG. 8(A)).

[0156] Furthermore, the image forming apparatus 1C adopting the changing means 6 of this modification example is also configured to be substantially the same as the operation in the modification example of the image forming apparatus 1 according to Embodiment 1 (FIGS. 8(A) and 9) regarding the operation when forming a toner image to be discarded.

[0157] Therefore, also in the image forming apparatus 1C adopting the changing means 6 of this modification example, since the transfer current when forming the toner image to be discarded is controlled to be changed by the changing means 6, the ratio of accommodating the toner of the toner image to be discarded is changed between the first collection container 61 (Y, M, C, K) and the third collection container 67. As a result, the replacement timing of at least one of the first collection container 61 (Y, M, C, K) and the third collection container 67 is adjusted.

[0158] Also, when changing the transfer current from the first transfer current to the second transfer current as in the configuration example of the changing means 6 of the above-described modification example, first, a large amount of the toner of the toner image to be discarded is accommodated in the third collection container 67, and after the storage capacity of the third collection container 67 reaches a value just before being full, the storage capacity to the black first collection container 61K having a relatively large storage volume is increased. For this reason, in this case, compared with the case where no such change in the primary transfer current is made, the replacement timing of the first collection container 61 (Y, M, C, K) can be delayed. In other words, in this case, the replacement timing of the third collection container 67 is slightly advanced compared with the case where no such change in the primary transfer current is made.

[0159] Embodiment 4. FIG. 17 shows an image forming apparatus 1D which is another example of the image forming apparatus according to Embodiment 4. The image forming apparatus 1D according to Embodiment 4 is different from the image forming apparatus 1C according to Embodiment 3 only in that it does not include a third collection container 67 for collecting unnecessary substances such as toner collected by the third cleaning device 76 of the transfer conveyance belt 71, and that it includes a changing means 6B whose changing content is different from the changing means 6 in Embodiment 3, and has the same configuration as the image forming apparatus 1C according to Embodiment 3.

[0160] As shown in FIG. 17, this image forming apparatus 1D does not include a third recovery container 67 (FIG. 16) for accommodating unnecessary substances such as toner recovered by the third cleaning device 76. Instead, in the image forming apparatus 1D, as shown in FIG. 17, among the first recovery containers 61 (Y, M, C, K) in the plurality of image forming devices 20 (Y, M, C, K), the black first recovery container 61K in one image forming device 20K is configured to have a larger accommodation volume than the other first recovery containers 61 (Y, M, C) in the remaining image forming devices 20 (Y, M, C), and unnecessary substances such as toner recovered by the third cleaning device 76 are accommodated in the black first recovery container 61K. Also, due to this configuration, in the image forming apparatus 1D, as a third recovery conveyance unit 77B for conveying unnecessary substances such as toner recovered by the third cleaning device 76, as shown in FIG. 17, a third recovery conveyance unit 77B is adopted that is configured in terms of position, shape, etc. so as to be connectable to the connection portion of the black first recovery container 61K.

[0161] Also, the changing means 6B in the fourth embodiment has substantially the same configuration as the changing means 6B in the second embodiment. That is, since the changing means 6B in the fourth embodiment does not include a dedicated third recovery container 67 for accommodating toner and the like recovered by the image forming apparatus 1D with the third cleaning device 76, and is configured such that one first recovery container 61K is also used as the third recovery container for the toner and the like, at least for the transfer current, a first transfer current for adjusting so that the toner of the toner image to be discarded is less likely to be transferred to the transfer conveyance belt 71 is changed to a second transfer current for adjusting so as to be reversely transferred to at least one photoreceptor 21 in the remaining image forming devices 20 (Y, M, C) (see FIG. 13(A)).

[0162] Also, the image forming apparatus 1D adopting the changing means 6B in the fourth embodiment is configured such that the operation when forming a toner image to be discarded is also substantially the same as the operation of the image forming apparatus 1B according to the second embodiment (FIGS. 13(A) and 14).

[0163] Therefore, even in the image forming apparatus 1D adopting this changing means 6B, since the transfer current when forming the toner image to be discarded is controlled to be changed by the changing means 6B, the ratio of accommodating the toner of the toner image to be discarded is changed in the first collection containers 61 (Y, M, C, K). As a result, at least one of the plurality of first collection containers 61 (Y, M, C, K) is efficiently adjusted in the replacement timing by using the yellow first collection container 61Y with the least amount of accommodated toner. Particularly in this case, the replacement timing of the black first collection container 61K with the largest accommodation volume can be delayed slightly compared to the case where the transfer current is not changed by the changing means 6B.

[0164] Embodiment 5. FIG. 18 and FIG. 19 show an image forming apparatus 1E which is another example of the image forming apparatus according to Embodiment 5.

[0165] The image forming apparatus 1E according to Embodiment 5 has the same configuration as the image forming apparatus 1 according to Embodiment 1, except that it applies a developer container 51 (Y, M, C, K) having supply storage parts 510Y, 510M, 510C, 510K for respectively storing powders supplied to developing devices 24 (Y, M, C, K) and recovery storage parts 610Y, 610M, 610C, 610K for respectively storing toners and the like recovered by first cleaning devices 26 (Y, M, C, K) instead of the developer containers 51 (Y, M, C, K) and the first collection containers 61 (Y, M, C, K) which are independent containers. In Embodiment 5, the first collection containers 61 (Y, M, C, K) which were independent containers are configured as recovery storage parts 610Y, 610M, 610C, 610K provided integrally with the developer container 51 (Y, M, C, K).

[0166] Also in the image forming apparatus 1E, similar to the case of the image forming apparatus 1 according to Embodiment 1, it is configured to form a toner image which is an example of a powder image to be discarded (recovered) without transferring it to the paper 9. In the image forming apparatus 1E, when toner images to be discarded are formed on the photoreceptors 21 in the four image forming devices 20 (Y, M, C, K), the primary transfer currents I(Y), I(M), I(C), I(K) respectively supplied from the power supply device 18 to the primary transfer rolls of the respective primary transfer devices 25 are changed by changing means 6 so that the amounts respectively stored in the recovery storage portions 610Y, 610M, 610C, 610K integrally provided in the developer containers 51 (Y, M, C, K) and the second recovery container 65 are adjusted (see FIG. 19).

[0167] This changing means 6 has substantially the same configuration as the changing means 6 in the first embodiment. In addition, the image forming apparatus 1E employing the changing means 6 in the fifth embodiment is configured such that the operation when forming the toner image to be discarded is also substantially the same as the operation of the image forming apparatus 1 according to the first embodiment (FIGS. 6(A) and 7).

[0168] Therefore, in this image forming apparatus 1E, since the primary transfer current when forming the toner image to be discarded is controlled to be changed by the changing means 6, the ratio of accommodating the toner of the toner image to be discarded is changed between the recovery storage portions 610 (Y, M, C, K) in the developer containers 51 (Y, M, C, K) and the second recovery container 65. As a result, at least one replacement timing of the developer container 51 (Y, M, C, K) having the recovery storage portion 610 (Y, M, C, K) and the second recovery container 65 is adjusted.

[0169] When changing the primary transfer current from the first transfer current to the second transfer current as in the configuration example of the changing means 6 in the first embodiment, since the ratio of accommodating the toner of the toner image to be discarded in the second recovery container 65 is reduced halfway, the replacement timing of the second recovery container 65 can be delayed compared to the case where the change of the primary transfer current is not performed.

[0170] In addition, in this image forming apparatus 1E, when compared with the case where the amounts of toner and the like respectively stored in the recovery storage section 610 (Y, M, C, K) and the second recovery container 65 in the developer container 51 (Y, M, C, K) are not controlled, when replacing the developer container 51 (Y, M, C, K), the amount (remaining amount) of unused and new toner remaining in the supply storage sections 510Y, 510M, 510C, 510K is suppressed. In other words, when replacing the developer container 51 (Y, M, C, K) having the supply storage sections 510Y, 510M, 510C, 510K and the recovery storage sections 610Y, 610M, 610C, 610K, the amount of toner remaining in the supply storage sections 510Y, 510M, 510C, 510K is suppressed, and it can be effectively used up almost completely.

[0171] The developer container 51 (Y, M, C, K) having the supply storage sections 510Y, 510M, 510C, 510K and the recovery storage sections 610Y, 610M, 610C, 610K may be applied to the image forming apparatuses 1B, 1C, 1D according to Embodiments 2, 3, and 4. When this is applied, the above-described operational effects by the changing means 6, 6B can be obtained in substantially the same manner.

[0172] Other modification examples. The present invention is not limited to the configuration examples illustrated in Embodiments 1 to 5, and can be changed without departing from the gist of the invention. For example, modification examples as described below are also included.

[0173] In Embodiments 1 to 4, as the first recovery container 61 that respectively stores the toner and the like recovered by the plurality of first cleaning devices 26, a configuration in which a plurality of dedicated first recovery containers 61 (Y, M, C, K) having the same number as the first cleaning devices 26 is applied was illustrated. However, as the first recovery container 61, one first recovery container 61 or a number of first recovery containers 61 less than the number of the plurality of first cleaning devices 26 may be applied.

[0174] In Embodiments 1 to 5, the image forming apparatuses 1, 1B, 1C, 1D, and 1E including four image forming devices 20 (Y, M, C, K) have been exemplified. However, as the image forming apparatus, an apparatus including an image forming device 20 having a number other than four may be used. The image forming device 20 may be one device.

[0175] In Embodiments 1 to 5, the case where a transfer current is applied as the transfer bias to be changed by the changing means 6, 6B has been exemplified. However, as the transfer bias to be changed, a transfer voltage supplied from the power supply device 18 can be similarly applied and changed. Even when this transfer voltage is applied, the changing means 6, 6B may change the transfer voltage so that the amounts of the powder accommodated in the first recovery container and the second recovery container or the third recovery container are adjusted.

[0176] In Embodiments 1 to 5, the image forming apparatuses 1, 1B, 1C, 1D, and 1E that use powder as a developer as the image forming apparatus have been exemplified. However, the image forming apparatus of the present invention is not particularly limited as long as it is an apparatus that electrostatically attaches powder to a sheet-like material by a transfer device. Examples of other image forming apparatuses include a powder coating apparatus that electrostatically attaches powder paint to a sheet-like material by a transfer device and paints it.

Explanation of Reference Numerals

[0177] 1, 1B, 1C, 1D, 1E... Image forming apparatuses (an example of an image forming apparatus) 6, 6B... Changing means 9... Paper (an example of a sheet-like material) 18... Power supply device 19... Detection means 20Y, 20M, 20C, 20K... Image forming devices (an example of a plurality of image forming devices) 21... Photoconductor (an example of an image holding body) 24Y, 24M, 24C, 24K... Developing devices 25... Primary transfer device (an example of a transfer device) 26... First cleaning device 31... Intermediate transfer belt (an example of an intermediate transfer body) 36... Second cleaning device 37B... Second recovery conveyance unit (an example of a conveyance path) 51Y, 51M, 51C, 51K… Developer container (an example of a powder container) 61Y, 61M, 61C, 61K… First recovery container 65… Second recovery container 67… Third recovery container 71… Transfer conveyance belt (an example of a transfer conveyance member) 76… Third cleaning device 510Y, 510M, 510C, 510K… Supply storage section 610Y, 610M, 610C, 610K… Recovery storage section B … Rotation direction (an example of the conveyance direction of an intermediate transfer member or a transfer conveyance member)

Claims

1. An image holding member for holding an image, A developing device for developing a latent image formed on the image holding member into a visible image composed of powder, An intermediate transfer member for temporarily transporting the visible image transferred from the image holding member, A transfer device for transferring the visible image of the image holding member to the intermediate transfer member, A first cleaning device for collecting and cleaning the powder remaining on the image holding member, A first recovery container for accommodating the powder recovered by the first cleaning device, A second cleaning device for collecting and cleaning the powder remaining on the intermediate transfer member, A second recovery container for accommodating the powder recovered by the second cleaning device, A power supply device for supplying a transfer bias to the transfer device, Changing means for changing the transfer bias supplied from the power supply device when a powder image to be discarded is formed on the image holding member so that the amounts of the powder of the discarded powder image accommodated in the first recovery container and the second recovery container are adjusted respectively, Comprising, A plurality of image forming devices including the image holding member, the developing device, the transfer device, the first cleaning device and the first recovery container are provided, and the plurality of image forming devices are arranged side by side in the transport direction of the intermediate transfer member, And the volume of the first recovery container in one of the plurality of image forming devices is configured to be larger than the volume of the first recovery container in the remaining image forming devices other than the one image forming device, And a transport path for transporting the powder recovered by the second cleaning device to the first recovery container in the one image forming device, and detection means for detecting the amount of the powder accommodated in the first recovery container are provided, And the changing means, When the detection means detects that the amount of the powder accommodated in the first recovery container of the one image forming device is less than a predetermined almost full amount close to full, the transfer bias is adjusted to a first transfer bias such that the powder of the discarded powder image is easily transferred to the intermediate transfer member, When the detection means detects that the amount of the powder is equal to or more than the predetermined almost full amount, the transfer bias supplied to the transfer device of the image forming device having the first recovery container with the least amount of the powder accommodated among the first recovery containers of the remaining image forming devices excluding the one image forming device is changed to a second transfer bias such that the powder of the discarded powder image is reversely transferred to the image holding member of the one image forming device. An image forming device.

2. An image holding member for holding an image, A developing device for developing a latent image formed on the image holding member into a visible image composed of powder, A transfer conveyance unit that conveys a sheet-like material for transferring the visible image of the image holding member; A transfer device that transfers the visible image onto the sheet-like material conveyed by the transfer conveyance unit; A first cleaning device that collects and cleans the powder remaining on the image holding member; A first recovery container that stores the powder recovered by the first cleaning device; A third cleaning device that collects and cleans the powder remaining on the transfer conveyance unit; A third recovery container that stores the powder recovered by the third cleaning device; A power supply device that supplies a transfer bias to the transfer device; Changing means for changing the transfer bias supplied from the power supply device when a powder image to be discarded is formed on the image holding member so that the amounts of the powder of the discarded powder image stored in the first recovery container and the third recovery container are adjusted respectively; Comprising; A plurality of image forming devices including the image holding member, the developing device, the transfer device, the first cleaning device, and the first recovery container are provided, and the plurality of image forming devices are arranged side by side in the conveyance direction of the intermediate transfer member, And the volume of the first recovery container in one of the plurality of image forming devices is configured to be larger than the volume of the first recovery container in the remaining image forming devices other than the one image forming device, And a conveyance path for conveying the powder recovered by the third cleaning device to the first recovery container in the one image forming device, and detection means for detecting the amount of the powder stored in the first recovery container are provided, And the changing means is When the detection means detects that the amount of the powder stored in the first recovery container of the one image forming device is less than a predetermined almost-full amount, the transfer bias is adjusted to a first transfer bias such that the powder of the discarded powder image is easily transferred onto the transfer conveyance unit, When the detection means detects that the amount of the powder is equal to or more than the predetermined almost-full amount, the transfer bias supplied to the transfer device of the image forming device including the first recovery container having the least amount of the stored powder among the first recovery containers of the remaining image forming devices excluding the one image forming device is changed to a second transfer bias such that the powder of the discarded powder image is reversely transferred onto the image holding member of the one image forming device. An image forming apparatus.

3. The image forming apparatus according to claim 1 or 2, further comprising a powder container having a replenishment storage portion for storing the powder replenished to the developing device, The first recovery container is configured as a recovery storage portion provided integrally with the powder container.

Images