JP2021110822A - Image forming apparatus - Google Patents

Abstract

To provide a technique that can appropriately detect the fullness of a toner recovery container even when there is a large difference in the amount of recovered waste toner (and waste developer) in respective colors.SOLUTION: An image forming apparatus comprises: a plurality of process units that use different types of toner to form toner images for the respective types of toner; transfer units that transfer the toner images to a sheet in an overlapped manner; a plurality of toner containers for replenishment that are attached while storing the toner supplied to the process units; a toner recovery container that stores a residual toner that is not transferred to the sheet and recovered on the transfer units and the process units to one container from the transfer units and the process units; and a control unit that refers to the history of use of the toner containers for replenishment to determine whether the toner recovery container is required to be replaced. When the number of the toner containers for replenishment used from when a new toner recovery container is attached exceeds a threshold predetermined for each type, the control unit determines that the toner recovery container is required to be replaced.SELECTED DRAWING: Figure 8A

Description

The present invention relates to an image forming apparatus including a plurality of process units for forming a toner image using a developer composed of a carrier and toner and collecting the residual toner, and a toner collecting container for accommodating the recovered toner.

In a full-color image forming apparatus that employs a two-component developing method, the toner remaining on the surface of the photoconductor and the intermediate transfer belt (hereinafter referred to as residual toner) is cleaned, and the residual toner is collected as waste toner in a toner collection container.
Further, in the normal two-component developer method, the toner in the developer is consumed with the formation of the toner image, and the amount of toner corresponding to the consumption is newly replenished, while the carrier is not consumed and the toner in the developer is not consumed. Remain in. When stirring is repeated to charge the developer using the carriers remaining in the developer, the charging performance of the developer gradually deteriorates. When the predetermined number of prints is reached, it is necessary to manually replace the developer in the developing device. The predetermined number of prints corresponds to the design life of the developer.

The trickle developing method is known as one means for extending the apparent life of the developer as compared with the usual two-component developing method. In contrast to the normal two-component development method in which only toner is replenished into the developer, the trickle development method replenishes carriers into the developer little by little together with toner, while replenishing excess carriers in the developer with toner. At the same time, it is discharged as a waste developer and discarded and collected. Since the carriers newly supplied together with the toner are replaced with the deteriorated carriers in the developing device, the charging performance is maintained and the deterioration of the image quality is suppressed as compared with the normal two-component developing method.
In the above-mentioned trickle developing method, a developer containing deteriorated unnecessary carriers discharged from the developer together with waste toner (hereinafter referred to as waste developing agent) is also configured to be collected in a toner recovery container.

Regardless of whether it is the normal two-component development method or the trickle development method, if the toner recovery container becomes full, the development operation is stopped, the user is notified, and the toner is replaced with a new toner recovery container. I need to get it. Therefore, a reliable full detection method is desired.
In order to facilitate the replacement by the user, the toner collection container is arranged at a position within reach of the user when the door provided on the front side of the image forming apparatus is opened, for example.
The following image forming apparatus is known for detecting the fullness of the toner recovery container and replacing it. An image forming apparatus designed to divert a used developer container (toner container) as a waste developer recovery container (waste toner container), in order to use an empty developer container as a recovery container. It notifies the user when it is necessary to keep it. That is, based on the relationship between the amount of developer consumed for a specific color and the amount of waste developer performed in the past, the waste developer collected between the time when a new developer container is installed and the time when it is emptied is used. Predict the amount. Then, if the expected amount of waste developer exceeds the free capacity of the currently installed waste developer recovery container, store the empty developer container to be replaced with a new developer container. Notify (see, for example, Patent Document 1).

Further, the following image forming apparatus is known for detecting the fullness of the collection container for collecting excess developer in the trickle developing method. The image forming apparatus includes a collection container for collecting excess developer discharged from the developer contained inside the developer, and a toner concentration detecting means for detecting the toner concentration of the developer contained inside the developer. To be equipped. Further, the fullness detecting means for detecting the fullness of the collection container based on the cumulative driving time of the toner replenishing means for replenishing the toner to the inside of the developing device, and the cumulative driving time for the fullness detection based on the detection result of the toner concentration detecting means. It is provided with a correction means for correction. The fullness detecting means detects fullness based on the corrected cumulative driving time of the toner replenishing means (see, for example, Patent Document 2).

JP-A-2019-03025 Japanese Unexamined Patent Publication No. 2008-0768559

In the case of a full-color image forming apparatus, waste toner (waste toner and waste development in the case of trickle development method) from four process units corresponding to each color of black (K), cyan (C), magenta (M), and yellow (Y) Agent) is collected. Even if there is a large difference in the amount of waste toner (and waste developing agent) collected for each color, it is necessary to be able to stably collect waste toner (and waste developing agent) and accurately detect the full state of the toner collection container. be.
When there is a large difference in the amount of waste toner (and waste developing agent) of each color, for example, a large amount of images with a high printing rate biased to any one of K, C, M, and Y are printed. The situation can be mentioned.
The present invention has been made in consideration of the above circumstances, and even if there is a large difference in the amount of waste toner (and waste developing agent) of each color, the toner collection container is full. It provides a method that can accurately detect.

The present invention accommodates a plurality of process units that form toner images for each type using different types of toner, a transfer unit that superimposes and transfers each toner image on paper, and toner to be supplied to each process unit. A plurality of replenishment toner containers to be mounted and residual toner collected by the transfer unit and each process unit without being transferred to the paper are received from the transfer unit and each process unit, and one container is used as waste toner. Whether or not the toner recovery container needs to be replaced by referring to the toner recovery container housed in the toner recovery container, the mounting detection unit that detects the mounting of the toner recovery container and each replenishment toner container, and the usage history of each replenishment toner container. The control unit includes a control unit for determining the toner, and the control unit collects toner when the number of replenishment toner containers used after the new toner collection container is installed exceeds a preset threshold for each type. Provided is an image forming apparatus that determines that the container needs to be replaced.

Further, from a different point of view, the present invention is a step in which the control unit of the image forming apparatus detects the attachment of a replenishing toner container corresponding to any of the process units for forming different types of toner images and accommodating the toner of each type. Then, in the image formation in which the toner image is formed by using the process unit and transferred to the paper, the step of detecting the attachment of the toner recovery container containing the toner to be recovered without being transferred and the new toner recovery container are mounted. Provided is a method for detecting a full state of a toner recovery container, which comprises a step of determining that the toner recovery container needs to be replaced when the number of replenishment toner containers used since then exceeds a predetermined threshold for each type. do.

In the image forming apparatus according to the present invention, the control unit replaces the toner recovery container when the number of replenishment toner containers used after the new toner recovery container is attached exceeds a predetermined threshold for each type. Therefore, even when there is a large difference in the amount of waste toner (and waste developer) collected for each color, the full state of the toner collection container can be accurately detected.
The method for detecting the full state of the toner recovery container according to the present invention also has the same effect.

It is sectional drawing which shows the schematic structure of the multifunction device as one Embodiment of an image forming apparatus. It is external perspective view of the toner recovery container attached to the image forming apparatus shown in FIG. It is explanatory drawing which shows the structure of the stirring shaft and the waste toner detection unit provided in the toner recovery container shown in FIG. It is a perspective view which shows the structure of the waste toner detection unit in this embodiment. It is explanatory drawing which shows the drive path from the 1st gear shown in FIG. 2 to the stirring shaft shown in FIG. (No load state) It is explanatory drawing which shows the drive path from the 1st gear shown in FIG. 2 to the stirring shaft shown in FIG. (Full) It is an exploded perspective view which shows the structure of the drive path from a driven gear to a stirring shaft. It is a block diagram which shows the electrical structure of the image forming apparatus shown in FIG. It is a graph which plotted the ratio of the waste developing agent in the waste toner and the waste developing agent recovered for a specific color with respect to the printing rate. It is the first flowchart which shows an example of the process executed by the control unit shown in FIG. 6 regarding replacement of a toner recovery container. 2 is a second flowchart showing an example of a process executed by the control unit shown in FIG. 6 regarding replacement of the toner recovery container. It is a flowchart which shows an example of the process executed by the control unit of FIG. 6 regarding the replacement of a toner cartridge. FIG. 5 is an explanatory diagram showing an example of a mode in which the threshold value is changed according to the printing rate of a specific color and the number of monthly prints in the third embodiment.

Hereinafter, the present invention will be described in more detail with reference to the drawings. It should be noted that the following description is exemplary in all respects and should not be construed as limiting the invention.
(Embodiment 1)

<< Schematic configuration of image forming apparatus >>
First, the configuration of a multifunction device, which is one aspect of the image forming apparatus according to the present invention, will be described.
As shown in FIG. 1, the multifunction device 100 includes an image forming unit 10, an automatic document conveying unit 20, and a document reading unit 30, and performs multicolor and monochromatic image forming processing on paper according to image data. conduct.
The automatic document transport unit 20 transports documents one by one to the document reading unit 30. The document reading unit 30 reads an image of a document transported by the automatic document transport unit 20. Further, the image is read by scanning the document placed on the document table 31 in which the glass plate is arranged on the upper surface of the document scanning unit 30.
Although the outline is shown by the alternate long and short dash line in FIG. 1, the toner recovery container 300 is detachably attached to the front side of the image forming portion 10. The toner collection container can be taken out by the user by opening an opening / closing door (not shown in FIG. 1) on the front side of the multifunction device 100, enabling the collection and disposal of the waste developing agent and the waste toner.

The image forming unit 10 has four process units corresponding to each color of black (K), cyan (C), magenta (M), and yellow (Y). In each process unit, a charger 5, a developer 2, and a cleaner 4 are arranged around a photoconductor drum 3 according to an electrophotographic method to form a toner image corresponding to each color. Further, each process unit includes a user-replaceable toner cartridge 60 that houses the toner to be replenished to the developer 2. In FIG. 1, only the developer 2, the photoconductor drum 3, the cleaner 4, and the charger 5 constituting the black (K) process unit are designated by reference, and cyan (C), magenta (M), and yellow ( Reference numerals are omitted for each process unit of Y) to make the figure easier to see. Although each process unit may be integrally mounted on the main body of the multifunction device 100, such a configuration is not essential, and the developer 2, the photoconductor drum 3, the cleaner 4, the charger 5, and the toner cartridge are not essential. A part or all of 60 may be individually mounted on the main body.

The image forming unit 10 is further formed by an exposure unit 1 and each process unit that expose the surfaces of the K, C, M, and Y photoconductor drums 3 corresponding to the pixels of the image to be formed. It has an intermediate transfer belt unit 6 on which each color toner image is transferred and superimposed. Furthermore, it has a secondary transfer belt unit 7 that transfers the superimposed toner images of each color to the paper, and a fixing unit 8 that fixes the toner image transferred on the paper to the paper. It also has a paper feed cassette 11 for feeding paper, a manual paper feed cassette 12, a paper discharge tray 14 for ejecting printed paper, and the like.

The developer 2 is a developer using a known trickle developing method. The trickle type developer discharges a preset amount of the developer in units of the number of printed sheets as a waste developer from the inside of the developer 2 to the toner collection container 300 on the front side. Therefore, the developing device 2 is provided with a conduit 2A having a built-in transfer screw having a rotation axis in the depth direction of the drawing.
The amount of waste developing agent contained in the toner recovery container 300 is designed in association with the number of prints, and the capacity of the toner recovery container 300 is designed in consideration of the amount of waste developing agent discarded per printed sheet. ..

The cleaner 4 collects untransferred toner (residual toner) remaining on the photoconductor drum 3 without being transferred to the intermediate transfer belt 61 described later by a cleaning blade. The recovered residual toner is discharged to the toner recovery container 300 as waste toner. Therefore, the cleaner 4 is provided with a conduit 4A having a built-in transfer screw having a rotation axis in the depth direction of the drawing.
The amount of waste toner stored in the toner collection container 300 is designed in association with the number of printed sheets, and the toner is collected in consideration of the amount of waste toner collected per printed sheet in addition to the above-mentioned waste developing agent. The capacity of the container 300 is designed. As for the amount of waste toner, the amount of waste toner collected per printed sheet is set on the assumption that the paper is of a standard size and the printing rate is a predetermined%. For example, assuming that the standard size is A4 and the printing rate is 5%, the capacity is set to be full with the amount of waste developing agent and waste toner recovered when 100,000 sheets are printed.

The intermediate transfer belt unit 6 is an intermediate transfer belt 61 spanned over four intermediate transfer rollers 64, an intermediate transfer belt drive roller 62, and an intermediate transfer belt driven roller 63 corresponding to process units of each color of K, C, M, and Y. It also has an intermediate transfer belt cleaning unit 65. The intermediate transfer roller 64 transfers the K, C, M, and Y color toner images formed on the photoconductor drum 3 by the electrophotographic process to the intermediate transfer belt 61. The K, C, M, and Y color toner images are sequentially superimposed and transferred on the intermediate transfer belt 61, guided to the secondary transfer belt unit 7, and transferred to the paper passing through the secondary transfer belt unit 7.
The intermediate transfer belt cleaning unit 65 collects the toner (residual toner) remaining on the intermediate transfer belt 61 without being transferred to the paper by the cleaning blade. The recovered residual toner is discharged to the toner recovery container 300 as waste toner. Therefore, the intermediate transfer belt cleaning unit 65 is provided with a conduit 65A having a transfer screw having a rotation axis in the depth direction of the drawing.

The secondary transfer belt unit 7 transfers the paper that is sent out from the paper feed cassette 11 or the manual paper feed cassette 12 and is conveyed along the paper transfer path shown by the alternate long and short dash line in FIG. 1 with the intermediate transfer belt 61. The toner image on the intermediate transfer belt 61 is transferred to paper by sandwiching it between the two.
The paper cassette 11 accommodates the paper to be fed one by one to the above-mentioned paper transport path. The manual paper feed cassette 12 places the paper to be fed to the paper transport path.
The fixing unit 8 is arranged on the downstream side of the secondary transfer belt unit 7 on the paper transport path shown by the alternate long and short dash line in FIG. 1, and passes the paper on which the toner image is transferred by the secondary transfer belt unit 7. .. Upon passing, the toner image is fixed to the paper by heating and pressurizing the paper with a heat roller and a pressure roller.

≪Construction of toner recovery container≫
Subsequently, the toner recovery container 300 will be described. As shown by the alternate long and short dash line in FIG. 1, the toner recovery container 300 is arranged across the process units of each color of K, C, M, and Y in the left-right direction, and the upper end thereof is the intermediate transfer belt cleaning in FIG. 1 in the height direction. It is located at the position of the conduit 65A of the unit 65, and the lower end is at the position where it overlaps with the exposure unit 1. Further, it has a predetermined thickness in the depth direction of FIG. 1, and a space for accommodating the waste developing agent and waste toner is formed inside.

FIG. 2 is an external perspective view of the toner recovery container 300 mounted on the image forming apparatus shown in FIG. 1 as viewed from the side facing each of the K, C, M, and Y color process units. As shown in FIG. 2, the toner recovery container 300 has individual waste developing agent receiving ports 94 that receive the waste developing agent discharged from the conduit 2A of the developing device 2 corresponding to the colors K, C, M, and Y. Have in. The conduit 2A of the developing device 2 of each color of K, C, M, and Y is shown by a thin two-dot chain line in FIG.
Further, the toner recovery container 300 has a waste toner receiving port 93 for receiving the waste toner discharged from the conduit 4A of the cleaner 4 individually corresponding to each color of K, C, M, and Y. The waste toner receiving port 93 of each color is arranged obliquely upward with respect to the waste developing agent receiving port 94 of each color. The conduit 4A of the cleaner 4 of each color K, C, M, and Y is shown by a thin alternate-dashed line in FIG.

Further, the toner recovery container 300 has a waste toner receiving port 95 at the upper end portion that receives the waste toner discharged from the conduit 65A of the intermediate transfer belt cleaning unit 65. The conduit 65A of the intermediate transfer belt cleaning unit 65 is shown by a thin alternate long and short dash line in FIG.
Inside the toner recovery container 300, partition plates that partially divide the internal space are formed in the substantially vertical direction, and waste developing agents and waste toner recovery chambers are formed for each color.

For example, the waste toner guided from the K-color conduit 2A to the toner recovery container 300 via the waste toner receiving port 93 falls downward and is deposited as waste toner on the bottom of the toner recovery container 300. Similarly, the waste developer led from the K-color conduit 4A to the toner recovery container 300 via the waste developer receiving port 94 falls downward and is deposited as a waste developer on the bottom of the toner recovery container 300. Similarly, the waste toner of the C color adjacent to the K color and separated by the partition plate also falls downward and is deposited as waste toner on the bottom of the toner collection container 300. The waste developing agent guided from the C-color conduit 4A to the toner recovery container 300 via the waste developing agent receiving port 94 also falls downward and is deposited as a waste developing agent on the bottom of the toner recovery container 300. The same applies to the M color and the Y color.

However, those collection chambers communicate at the bottom. That is, no partition plate is formed on the bottom of the toner recovery container 300, and a stirring shaft 210 (shown by a two-dot chain line in FIG. 2) penetrating the bottom in the left-right direction is arranged. The stirring shaft 210 is driven by a first gear 201 driven by a motor (not shown) that drives the mechanism of the multifunction device 100, and rotates around the shaft. Further, a waste toner detection unit 200 is provided in the drive path from the first gear 201 to the stirring shaft 210, and detects that the waste toner in the toner recovery container 300 is full.

<< Configuration of stirring shaft and waste toner detection unit >>
FIG. 3 is an explanatory diagram showing a configuration of a stirring shaft and a waste toner detection unit 200 provided in the toner recovery container shown in FIG. FIG. 4A is a perspective view showing the configuration of the waste toner detection unit in this embodiment. As shown in FIG. 3, the stirring shaft 210 includes a plurality of stirring blades 211 protruding from the peripheral surface, and the waste toner and waste developing agent stored in the toner recovery container 300 due to the rotation of the stirring shaft 210. The stirring blade 211 comes into contact with the surface of the waste toner and the waste developer to level the surface. This prevents the waste toner and the waste developing agent in the toner recovery container 300 from being unevenly stored in the axial direction of the stirring shaft 210.
Further, as shown in FIG. 3, the waste toner detection unit 200 includes a drive cam gear 220, a driven cam 230, a drive cam 240, a photo interrupter 260, a cam spring 270, and a light-shielding member 280.
When the waste toner and the waste developing agent in the toner recovery container 300 approach the full state, the amount and density of the waste toner and the waste developing agent in contact with the stirring blade 211 increase. Therefore, the rotational load of the stirring shaft 210 increases. The waste toner detection unit 200 detects that the waste toner and the waste developer in the toner recovery container 300 are full by utilizing this characteristic.

4B and 4C are explanatory views showing the details of the drive path from the first gear 201 shown in FIG. 2 to the stirring shaft 210 shown in FIG. 3 and the waste toner detection unit 200. FIG. 5 is an exploded perspective view showing the configuration of the drive path from the drive cam gear 220 to the stirring shaft 210.
FIG. 4B shows a no-load state in which there is no waste toner and waste developing agent in the toner recovery container 300, and FIG. 4C shows a state in which the waste toner and waste developing agent in the toner recovery container 300 are full.

As shown in FIG. 4B, the rotation of the first gear 201 rotates integrally with it and is transmitted from the coaxial worm gear to the second gear 202, rotates integrally with the second gear 202, and drives from the coaxial third gear 203. It is transmitted to 220. The drive cam gear 220 is coaxial with the stirring shaft 210 and rotatably attached to the stirring shaft 210, and is axially attached between the outer periphery on which the teeth are formed and the central portion inserted into the stirring shaft 210. It has a spoke portion in which a plurality of holes are formed.
As shown in FIG. 5, the drive cam 240 has a flange portion 250 formed on the outer periphery thereof, and a plurality of columnar claws extending in the axial direction from the collar portion 250 are formed at the end portion on the side facing the drive cam gear 220. Has been done. These claws are inserted into holes formed in the spokes of the drive cam gear 220, both of which rotate integrally around the axis, and the drive cam 240 is slidable in the axial direction with respect to the drive cam gear 220. A cam spring 270 is arranged between the two, and one end in the axial direction pushes the side surface of the drive cam gear 220, and the other end pushes the side surface of the flange portion 250. The elasticity of the cam spring urges the drive cam 240 away from the drive cam gear 220.

The side surface of the drive cam 240 opposite to the cam spring 270 faces the driven cam 230, and a cam surface having peaks and valleys is formed. A cam surface having valleys and peaks corresponding to the side surfaces of the driven cam 230 facing the drive cam 240 is formed. The cam spring 270 pushes the cam surface of the drive cam 240 toward the cam surface of the driven cam 230. In a no-load state where there is no waste toner and waste developing agent in the toner recovery container 300, the peak portion of the drive cam 240 faces the valley portion of the driven cam 230 due to the pressing force of the cam spring 270, and the valley portion of the drive cam 240 is formed. It faces the mountain part of the driven cam 230. Then, the rotational force around the axis is transmitted from the drive cam 240 to the driven cam 230 via both cam surfaces.

The driven cam 230 is attached to the stirring shaft 210, and the driven cam 230, the stirring shaft 210, and the stirring blade 211 rotate integrally by the driving force transmitted from the driving cam 240 via the cam surface.
When the waste toner and the waste developing agent stored in the toner recovery container 300 are stored, the rotational load of the stirring shaft 210 increases. When the rotational load increases, the peaks of the driven cam 230 and the valleys of the drive cam 240, which are opposed to each other on the inclined cam surface when no load is applied, are out of phase with each other. Further, the phase of the valley portion of the driven cam 230 and the peak portion of the drive cam 240 are out of phase.

Due to the rotational load, the cam spring 270 is in a more compressed state than in the no-load state. Along with this, the flange portion 250 of the drive cam 240 slides in the direction of the arrow L shown in FIG. 4C, that is, in the direction approaching the drive cam gear 220. As the collar portion 250 approaches the drive cam gear 220, the light-shielding member 280 moves in the direction of the arrow D shown in the figure and is inserted into the slit portion of the photo interrupter 260.
When the rotational load of the stirring shaft 210 is further increased, the peak portion of the drive cam 240 reaches the peak portion of the driven cam 230, and the two are disengaged from each other. The collar 250 does not come closer to the drive cam gear 220. Therefore, the light-shielding member 280 does not move further to the back side of the slit portion of the photo interrupter 260.

≪Electrical configuration of multifunction device≫
Subsequently, the electrical configuration of the multifunction device 100 will be described.
FIG. 6 is a block diagram showing an electrical configuration of the image forming apparatus shown in FIG.
As shown in FIG. 6, the multifunction device 100 includes a control unit 110, a mounting detection unit 120, a waste toner detection unit 200, an operation unit 140, and a storage unit 150.
The control unit 110 controls the operation of each unit of the multifunction device 100. That is, the operations of the image forming unit 10, the automatic document conveying unit 20, and the document reading unit 30 are controlled.
The control for the image forming unit 10 includes, for example, a process of controlling the exposure unit 1 so as to expose each photoconductor drum 3 corresponding to the pixels of the image to be formed. It also includes a counting process for the number of exposed pixels (pixel count). Further, it includes control of charging of each photoconductor drum 3 by the charger 5 and control of transfer voltage applied to each intermediate transfer roller 64 and secondary transfer belt unit 7, respectively. Furthermore, it includes drive control of each photoconductor drum 3, intermediate transfer belt unit 6, and secondary transfer belt unit.
The control unit 110 uses a sensor (not shown) provided in each developer 2 to replenish the toner from each toner cartridge 60 to each developer 2 in order to keep the toner concentration of the contained developer at a predetermined value. Control. Further, the amount of toner replenished from each toner cartridge 60 is monitored to estimate the remaining amount of each toner cartridge 60. Then, it is determined that each toner cartridge 60 is empty.
Further, the control unit 110 controls the operations of the fixing unit 8, the paper feed cassette 11, and the manual paper feed cassette 12. Further, the mounting detection unit 120 recognizes the mounted / non-mounted state of each toner cartridge 60 and the mounted / non-mounted state of the toner recovery container 300. In addition, the waste toner detection unit 200 recognizes the full state of the toner collection container 300. Then, the operation unit 140 displays the status and message of the multifunction device 100, and receives the user's instruction. In addition, data is stored in the storage unit 150, and the stored data is referred to. The data includes a usage history of each toner cartridge 60.

The mounting detection unit 120 detects the mounting / non-mounting state of the K, C, M, and Y color toner cartridges 60 and the toner collection container 300. The control unit 110 recognizes the detection by the mounting detection unit 120.
The photo interrupter 260 of the waste toner detection unit 200 detects the full state of the toner recovery container 300 as described above.
The storage unit 150 is configured to include a non-volatile memory, and stores a used toner cartridge counter related to the usage history of each color toner cartridge 60 of K, C, M, and Y. In this embodiment, the control unit 110 stores in the used toner cartridge counter the number of toner cartridges of each color used as the usage history of each toner cartridge 60.
The operation unit 140 includes a display device that displays the status of the multifunction device 100 and an input device that accepts user input.

≪Correspondence to bias that cannot be evened out with stirring blades≫
In the multifunction device 100 of this embodiment, the toner recovery container 300 is arranged on one end side of the cleaner, the intermediate transfer belt cleaning unit, and the developer without providing a complicated transport path for the waste toner and the waste developer, and the waste toner and the waste developer are arranged. The waste developer is collected in the toner collection container 300.
That is, the waste toner is discharged from each of the K, C, M, and Y cleaners 4 and the intermediate transfer belt cleaning unit 65, respectively, and the toner recovery container 300 is arranged on one end side thereof and corresponds to a plurality of them. It has waste toner receiving ports 93 and 95. Further, since the multifunction device 100 employs a trickle developing method, the waste developing agent is discharged from each of the K, C, M, and Y developing machines 2 to the toner recovery container 300 on one end side thereof. The toner recovery container 300 has a plurality of waste developing agent receiving ports 94 corresponding to them.

In particular, in the trickle developing method, the waste developing agent is recovered in addition to the waste toner, so it is important to have a configuration that realizes the recovery of the waste toner and the waste developing agent by a simple mechanism and route.
In this embodiment, the toner recovery container 300 rotates the stirring blades arranged inside around the axis to level the stored waste toner and waste developing agent, and has a large load torque when rotating the stirring blades. The bulk of the stored waste toner and waste developer is detected to determine the full state. According to this configuration, it is not necessary to detect the recovered amount individually for each color, and the full state of the toner recovery container 300 can be detected with a simple configuration.
When each color is used at the same printing rate, waste toner and waste developer are present in almost the entire area of the stirring shaft 210 and the stirring shaft 210, so that they are accommodated in the toner recovery container 300 by the load torque of the stirring shaft 210. The bulk of waste toner and waste developer can be detected.

However, waste toner and waste developing agent may be present only in a part of the stirring shaft 210 and the stirring blade 211, and it may not be possible to accurately detect the local full state due to the load torque of the stirring shaft 210. ..
That is, when the amount of waste toner of any color is very large compared to the amount of waste developer of another color, for example, when the printing rate of a specific color is extremely high as compared with other colors. Can rarely occur. In that case, waste toner of a specific color may be locally accumulated and reach the waste toner receiving port 93. In that case, the accumulated waste toner blocks the waste toner receiving port 93.

In such a situation, a large amount of waste toner and waste developing agent are deposited around the stirring shaft 210 and the stirring blade 211 in some places corresponding to the above-mentioned colors, but waste toner of other colors and waste toner of other colors are deposited. The amount of waste developer deposited is smaller than that. Therefore, the load torque of the stirring shaft, which is the total of each color, does not reach the threshold value for full detection, and the waste toner detection unit 200 cannot detect the local full state of the toner recovery container 300.
Even if the waste toner receiving port 93 is blocked, the collected waste toner is conveyed toward the waste toner receiving port 93 inside the cleaner 4. Therefore, the waste toner stays in the vicinity of the waste toner receiving port 93 inside the cleaner 4, and is compressed and solidified. Then, the cleaner 4 is locked by the waste toner solidified inside.

In the multifunction device 100 that employs the trickle developing method, the toner cartridge 60 houses a developer composed of a carrier and toner, and the carrier is supplied to the developer 2 at the same time as the toner. The developer 2 discharges the excess amount as a waste developer from the developer so that the bulk of the developer in the developer becomes a constant amount. The discharged waste developing agent is discharged to the toner recovery container 300 via the waste developing agent receiving port 94.
When printing a large amount of an image having a high printing rate only for a specific color, a large amount of toner for that color is used for printing. To compensate for this, the control unit 110 replenishes a large amount of developer from the toner cartridge 60. As the toner is replenished, the carriers inside the developer 2 also increase, and the toner and carriers in the developer 2 collect the toner through the waste developer receiving port 94 by the amount corresponding to the increase in bulk due to the increase in carriers. It is discharged to the container 300. Therefore, the amount of waste carriers of a specific color recovered is higher than that of other colors.

When only a specific color is printed and no other color is printed (for example, when monochrome printing using only K is continuous), the specific color collected in the toner collection container 300 as the printing rate of the specific color increases. The ratio of the waste developer to the waste toner is high. That is, as the printing rate increases, the ratio of waste carriers to waste toner and waste carriers increases.
Here, for example, assuming that the transfer efficiency of K is 90% only in monochrome printing, first consider other colors C, M, and Y other than K. For other colors, a small amount of fog (toner remaining on the transfer) that is not used for printing (not transferred) is generated. The generated fog (toner) is collected from the cleaner 4 or the intermediate transfer belt cleaning unit 65 as waste toner in the toner collection container 300 via the waste toner receiving port 93 or 95. That is, the other C, M, and Y developing units 2 are replenished with a small amount of toner corresponding to the waste toner. This means that almost all of the fog remaining on the transfer is collected as waste toner in the toner collection container 300. From this, for C, M, and Y, the amount of toner replenished is small, and the amount of carriers replenished is also small, so that the amount of waste developer of other colors is very small. .. That is, for C, M, and Y, the ratio of waste carriers to waste toner and waste carriers is small.
On the other hand, with respect to K, toner having a printing rate of 10% is not transferred to the paper but is stored in the toner collection container 300 from the cleaner 4 or the intermediate transfer belt cleaning unit 65 via the waste toner receiving port 93 or 95. ..
On the other hand, a developer corresponding to the amount of toner used for printing is replenished from the toner cartridge 60 to the developer 2, and the carriers inside the developer 2 also increase. Then, the developer corresponding to the bulk increase is stored in the toner recovery container 300 as a waste developer via the waste developer receiving port 94. Therefore, for K, the proportion of waste carriers and waste carriers stored in the toner recovery container 300 is higher than that of other colors.

FIG. 7 is a graph in which the ratio of waste carriers to waste toner and waste carriers recovered for a specific color is plotted against the printing rate. In FIG. 7, the proportion of waste carriers is shown by weight ratio and volume ratio.
As shown in FIG. 7, as the printing rate of a specific color increases, the ratio of waste toner and waste carriers to the waste carriers that are recovered increases in both weight ratio and volume ratio.
The amount of waste toner and waste developer of a specific color discharged per unit time increases as the printing rate of the image increases. In addition, the higher the frequency of printing, the higher the amount of emissions per unit time. When the amount of discharge per unit time is large, the effect of leveling due to the rotation of the stirring blade 211 is not sufficiently exhibited, and waste toner and waste developing agent are locally deposited.

Further, the waste toner and the waste developing agent deposited on the toner recovery container 300 have a property of decreasing in volume (tightening) due to their own weight with the passage of time. However, if a large amount of waste toner and waste developing agent are deposited in a short period of time, they are deposited in the toner recovery container 300 in a bulky state. Then, the waste toner or the waste developing agent is deposited one after another before the bulk is reduced, and the top of the accumulated waste toner or the waste developing agent reaches the waste toner receiving port 93 or the waste developing agent receiving port 94. Then, as described above, the waste toner receiving port 93 or the waste developing agent receiving port 94 may be blocked.
In this embodiment, since the waste developer receiving port 94 is located at a position lower than the waste toner receiving port 93, it is fully conceivable that the waste developing agent receiving port 94 is blocked before the waste toner receiving port 93. ..
In any case, if the amount of waste discharged per unit time is large, the bulk density of the waste toner and the waste developer is low, so that the fullness detection due to the load torque of the stirring shaft cannot be performed accurately.

Therefore, in this embodiment, the fullness of the toner recovery container 300 is detected by the conventional waste toner detection unit 200 to detect the load torque of the stirring shaft 210, and the toner recovery container 300 is replaced based on the usage history of the toner cartridge 60. The control unit 110 determines the necessity.
More specifically, whether or not the control unit 110 needs to replace the toner recovery container 300 based on the cumulative value for each color of the number of toner cartridges 60 of each color used after the new toner recovery container 300 is mounted. Is determined. In other words, either it is detected that the waste toner and the waste developing agent in the toner recovery container 300 have reached a predetermined bulk, or the cumulative usage amount in which the toner cartridge 60 has been used since the toner recovery container 300 is mounted is either. It is determined whether or not the toner recovery container 300 needs to be replaced, whichever comes first, whichever exceeds the threshold value for the color of.
According to this configuration, sensors are placed in multiple locations and a complicated transfer mechanism for waste toner and waste developer is added as a response to the case where a large number of images with a high print rate biased to one color are printed. It is possible to detect a local full condition without adding a mechanism for increasing the leveling ability.

8A and 8B are flowcharts showing an example of the process executed by the control unit shown in FIG. 6 regarding the replacement of the toner recovery container. FIG. 9 is a flowchart showing an example of a process executed by the control unit of FIG. 6 regarding replacement of the toner cartridge. Hereinafter, the processing of the control unit related to the replacement of the toner recovery container 300 will be described with reference to the flowchart.
In the flowcharts of FIGS. 8A, 8B, and 9, each process is described as a series of flows, but in reality, the control unit 110 executes those processes by multitasking in parallel with the other processes. do.

As shown in FIG. 8A, the control unit 110 sequentially monitors whether or not the waste toner detection unit 200 has detected the full state (step S11).
When the full state is detected (Yes in step S11), the process proceeds to step S19 described later, and a message indicating that a replacement toner collection container should be prepared is displayed on the operation unit 140. For example, a message such as "It's about time to replace the toner recovery container. Please prepare a new toner recovery container." Then, counting of the pixel count value of each color related to the determination of the replacement time of the toner recovery container 300 is started (step S21).

On the other hand, when the waste toner detection unit 200 has not detected the full state in step S11 (No in step S11), the control unit 110 refers to the storage unit 150 and uses toner cartridge counters 150K, 150C for each color. 150M and 150Y are compared with a predetermined threshold value (step S13).
When the used toner cartridge counter of any color exceeds the threshold value (Yes in step S15), the control unit 110 further determines the residual toner in the toner cartridge 60 for the color for which the used toner cartridge counter exceeds the threshold value. It is determined whether or not the amount is close to empty (step S17). In the flowchart of FIG. 8A, as an example of a state close to the sky, it is determined whether or not the remaining amount is less than 10%.

If the toner cartridge is almost empty (Yes in step S17), the control unit 110 proceeds to step S19 in the same manner as when the waste toner detection unit 200 detects the full state in step S11 described above.
After that, the control unit 110 checks whether or not the operation unit 140 has received the instruction to delete the message displayed on the operation unit 140 in step S19 (step S23). When the instruction to clear the message is received (Yes in step S23), the message is deleted (step S25). If the instruction to clear the message is not accepted (No in step S23), the process in step S25 is skipped and the message is maintained.

Further, the control unit 110 checks whether or not the pixel count value related to the replacement determination of the toner collection container 300, which started counting in step S21, has reached a predetermined value (step S27).
If the pixel count value has not reached a predetermined value (No in step S27), the processing flow returns to step S23 described above and waits for an instruction to clear the message.
On the other hand, when the pixel count value reaches a predetermined value (Yes in step S27), the control unit 110 stops the image forming operation to prevent the waste toner and the waste developing agent from being discharged any more. Then, a message indicating that the toner collection container should be replaced is displayed on the operation unit 140 (step S29 in FIG. 8B). For example, the message "Please replace the toner collection container."

Then, the control unit 110 waits for the mounting detection unit 120 to detect the replacement (removed state) of the toner collection container 300 (step S31), resets the used toner cartridge counter to zero, and sets the operation unit 140. Clear the message related to the toner collection container displayed in (step S33).
Then, the process returns to step S11, and the fullness detection of the toner collection container and the monitoring of the used toner cartridge counter are continued.
The toner cartridge counter used for each color is reset by the process of step S33 in FIG. 8B, but the count-up process is not in FIGS. 8A and 8B, and the count-up process is performed in the flowchart of FIG. 9 described below. Processing is done.

FIG. 9 is a process in which the control unit 110 sequentially monitors the detection by the mounting detection unit 120. As shown in FIG. 9, the control unit monitors whether or not the toner cartridge 60 of any color is installed (step S41), and determines the value of the toner cartridge counter of the color corresponding to the case where the toner cartridge 60 is installed. Add 1
In FIG. 9, the used toner cartridge counter is counted up when the toner cartridge is installed, but instead, the used toner cartridge counter may be counted up when the toner cartridge is removed. ..

(Embodiment 2)
In the first embodiment, a used toner cartridge counter that counts the number of used toner cartridges 60 is used to detect a locally full state of the toner recovery container 300 that occurs when high-density printing that is biased to one color is continuous. ..
In this embodiment, the local full state of the toner recovery container 300 is detected by using the cumulative rotation speed or the cumulative rotation time of the toner replenishment motor instead of the number of used toner cartridges 60.
Here, the toner replenishment motor is a motor provided corresponding to the toner cartridge 60 of each color and driving a toner replenishment mechanism (not shown). The toner replenishment mechanism replenishes the toner contained in each toner cartridge 60 to the corresponding developer 2, and is provided for each color.

The cumulative rotation speed or cumulative rotation time of the toner replenishment motor is used to estimate the remaining amount of toner in the toner cartridge 60. That is, a predetermined amount of toner is contained in the new toner cartridge 60. Assuming that the cumulative rotation speed of the toner replenishment motor after the new toner cartridge 60 is installed is substantially proportional to the amount of replenished toner, the toner replenished from the amount of toner contained in the new toner cartridge 60 The remaining amount of toner can be estimated by subtracting the amount of toner.
When the toner replenishment motor rotates at a constant speed, the cumulative rotation time of the toner replenishment motor is proportional to the cumulative rotation speed and substantially proportional to the amount of replenished toner. Therefore, the remaining amount of toner can be estimated by using the cumulative rotation time instead of the cumulative rotation speed of the toner replenishment motor.

In the trickle development method, a predetermined amount of carriers is also contained in the new toner cartridge together with a predetermined amount of toner. The variation in the filling amount of toner and carrier is small. Therefore, by counting the number of toner cartridges 60 used for each color, the amount of toner and carriers supplied to the developer 2 for each color can be grasped substantially accurately. However, the minimum unit is the amount of toner and carriers per toner cartridge 60. The amount of waste toner collected in the toner collection container 300 is obtained by multiplying the amount of toner supplied to the developing device 2 by the ratio of waste toner collected as waste toner. The ratio correlates with the transfer efficiency of the toner.

When estimating the toner replenishment amount based on the cumulative rotation speed or the cumulative rotation time of the toner replenishment motor, the toner replenishment amount to the developer 2 per unit rotation speed or unit rotation time depends on the toner state and varies. .. That is, there is a possibility that the actual toner replenishment amount and the cumulative rotation speed are not proportional to each other and a deviation occurs.
If the deviation is large, the toner replenishment amount can be estimated more accurately by detecting with the cumulative number of toner cartridges used, so the toner replenishment amount can be estimated more accurately based on the cumulative rotation speed or cumulative rotation time of the toner replenishment motor. Not always possible.

(Embodiment 3)
As described in the first embodiment, under the usage conditions in which the amount of waste toner and waste developer of a specific color discharged is much larger than that of other colors, local waste toner is locally based on the number of toner cartridges 60 used. It is possible to detect when the box is full.
In this embodiment, in order to further improve the detection accuracy, the threshold value for determining the toner cartridge counter used is changed according to the usage conditions of the specific color, more specifically, the printing rate and the printing frequency of the specific color.

FIG. 10 is an explanatory diagram showing an example of a mode in which the threshold value is changed according to the printing rate of a specific color and the number of monthly prints in this embodiment. In the example shown in FIG. 10, the average printing rate of a specific color is divided into three stages of less than 10%, 10% or more and less than 30%, and 30% or more, and threshold values are set according to each stage. In the case of a high printing rate, the bulk of the waste toner and the waste developing agent is not tightened as compared with the low printing rate, and the waste toner and the waste developing agent are deposited at a high bulk density. Therefore, a low threshold value is set so that the toner recovery container 300 is replaced as soon as possible.
Regarding the printing frequency, the monthly printing number is divided into four stages of less than 30,000, 30,000 or more and less than 100,000, 100,000 or more and less than 300,000, and 300,000 or more. Thresholds are set according to each stage. In the case of high printing frequency (large number of monthly prints), the bulk of waste toner and waste developer is not tight compared to low printing frequency (small number of monthly prints), and the waste toner and the waste developer are deposited at a high bulk density. Set a low threshold to exchange.
This makes it possible to further improve the detection accuracy of the local full state of the toner recovery container 300.

(Embodiment 4)
In the first embodiment, the necessity of replacing the toner recovery container 300 is determined by combining the full detection of the toner recovery container 300 by the waste toner detection unit 200 and the detection of the local full state based on the number of used toner cartridges. ing.
However, it is also possible to determine whether or not the toner recovery container 300 needs to be replaced only by detecting the full state based on the number of used toner cartridges without providing the waste toner detection unit 200.

As mentioned above
(I) The image forming apparatus according to the present invention includes a plurality of process units for forming each type of toner image using different types of toner, a transfer unit for transferring each toner image on paper, and each process unit. A plurality of replenishing toner containers, each of which houses and mounts toner to be supplied to, and residual toner collected by the transfer unit and each process unit without being transferred to the paper are transferred from the transfer unit and each process unit. Refer to the toner recovery container that receives and stores the waste toner in one container, the mounting detection unit that detects the mounting of the toner recovery container and each replenishment toner container, and the history of use of each replenishment toner container. The control unit is provided with a control unit that determines whether or not the toner recovery container needs to be replaced, and the control unit has a predetermined threshold value for each type of the number of replenishment toner containers that have been used since the new toner recovery container was installed. It is characterized in that it is determined that the toner recovery container needs to be replaced when the above value is exceeded.

In the present invention, the process unit forms a toner image for each type using different types of toner by an electrophotographic process. In a specific embodiment thereof, for example, a full-color toner image is formed by four process units corresponding to each color of black (K), cyan (C), magenta (M), and yellow (Y). However, the type of toner is not limited to this, and for example, other colors may be included, and for example, a toner image is formed by using toners for a high density part and a low density part for the same color. May be good. In the above-described embodiment, the charger, developer, cleaner, and toner cartridge corresponding to each color constitute a process unit related to that color.

The toner cartridges of each color correspond to the replenishment toner container in the present invention.
Further, the transfer unit superimposes the toner images formed by each process unit and transfers them onto paper. The intermediate transfer belt unit and the secondary transfer belt unit in the above-described embodiment correspond to the transfer unit of the present invention.
Furthermore, the history of use of the replenishment toner container is a history indicating when the replenishment toner container for each type became empty and when it was replaced with a new replenishment toner container, which can be referred to by the control unit. Stored in memory.

Further, preferred embodiments of the present invention will be described.
(Ii) Each process unit includes a trickle type developer, each replenishing toner container accommodates a developer composed of a carrier and toner and supplies the developer to the corresponding developer, and the toner recovery container is used for each developing. It may further have a waste developer inlet corresponding to each process unit for receiving the developer discharged from the vessel, and the waste toner and the waste developer may be contained in one container.
In this way, even if there is a large difference in the amount of waste toner and waste developer of each color recovered in the trickle development method for recovering waste developer in addition to waste toner, the toner recovery container is filled. It can be detected accurately.

(Iii) A waste toner detection unit for detecting the full state of the stored waste toner is further provided, and the control unit is equipped with a new toner recovery container after the waste toner detection unit detects the full state. When the number of replenishment toner containers used from the above exceeds the threshold value for each type, it may be determined that the toner recovery container needs to be replaced.
In this way, if there is no large difference in the amount of waste toner (and waste developing agent) collected for each color, it can be determined that the toner collection container needs to be replaced based on the detection that the toner collection container is full by the waste toner detection unit. .. On the other hand, if there is a large difference in the amount of waste toner (and waste developing agent) collected for each color, it can be determined that the toner collection container needs to be replaced based on the number of replenishment toner containers used.

(Iv) An operation unit for displaying a message may be further provided, and when the control unit determines that the toner recovery container needs to be replaced, the operation unit may display a message relating to the replacement of the toner recovery container.
In this way, when the control unit determines that the toner collection container needs to be replaced, a message can be displayed on the operation unit to prompt the user to take action.

(V) The control unit may change the threshold value according to the execution frequency and printing rate of image formation performed after mounting the toner recovery container.
In this way, for example, when the amount of waste toner collected per unit print number of a specific type of waste toner (and waste developing agent) is large, the threshold value is set smaller than usual and the toner collection container is opened earlier. Can be exchanged by the user.

(Vi) Further, in a preferred embodiment of the present invention, the control unit of the image forming apparatus is equipped with a replenishing toner container corresponding to any of the process units for forming different types of toner images and accommodating each type of toner. A step of detecting, a step of detecting the attachment of a toner recovery container containing toner to be recovered without being transferred in image formation in which a toner image is formed using the process unit and transferred to paper, and a new toner recovery container. Detects the full state of the toner recovery container, which comprises a step of determining that the toner recovery container needs to be replaced when the number of replenishment toner containers used after the is installed exceeds a predetermined threshold for each type. Including method.

Preferred embodiments of the present invention include a combination of any of the plurality of embodiments described above.
In addition to the embodiments described above, there may be various variations of the present invention. These variations should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the claims and all modifications within the said scope.

1: Exposure unit, 2: Developer, 2A, 4A, 65A: Conduit, 3: Photoreceptor drum, 4: Cleaner, 5: Charger, 6: Intermediate transfer belt unit, 7: Secondary transfer belt unit, 8: Fixing unit, 10: Image forming unit, 11: Paper cassette, 12: Manual paper feed cassette, 14: Paper output tray, 20: Automatic document transfer unit, 30: Document reading unit, 31: Document stand, 60: Toner cartridge , 61: Intermediate transfer belt, 62: Intermediate transfer belt drive roller, 63: Intermediate transfer belt driven roller, 64: Intermediate transfer roller, 65: Intermediate transfer belt cleaning unit, 93, 95: Waste toner inlet, 94: Waste development Agent inlet, 100: Multi-function machine, 110: Control unit, 120: Mounting detection unit, 140: Operation unit, 150: Storage unit, 150K, 150C, 150M, 150Y: Toner cartridge counter used, 200: Waste toner detection unit , 201: 1st gear, 202: 2nd gear, 203: 3rd gear, 210: stirring shaft, 211: stirring blade, 220: drive cam gear, 230: driven cam, 240: drive cam, 250: flange, 260 : Photo interrupter, 270: Cam spring, 280: Shading member, 300: Toner recovery container

Claims (6)

Multiple process units that form each type of toner image using different types of toner,
A transfer unit that superimposes each toner image on paper and transfers it,
A plurality of replenishment toner containers that accommodate and install toner to be supplied to each process unit,
A toner recovery container that receives residual toner collected by the transfer unit and each process unit without being transferred to the paper from the transfer unit and each process unit and stores it as waste toner in one container.
A mounting detection unit that detects the mounting of the toner recovery container and each replenishment toner container, and
It is equipped with a control unit that determines whether or not the toner recovery container needs to be replaced by referring to the usage history of each replenishment toner container.
The control unit forms an image that determines that the toner recovery container needs to be replaced when the number of replenishment toner containers used after the new toner recovery container is attached exceeds a predetermined threshold value for each type. Device. Each process unit includes a trickle-type developer
Each replenishment toner container contains a developer consisting of a carrier and toner and supplies it to the corresponding developer.
The toner recovery container further has a waste developer receiving port corresponding to each process unit for receiving the developer discharged from each developer, and stores the waste toner and the waste developer in one container. The image forming apparatus according to claim 1. Further equipped with a waste toner detection unit that detects the full state of the stored waste toner,
When the number of replenishment toner containers used after the waste toner detection unit detects a full state or a new toner recovery container is installed exceeds the threshold value for each type, the control unit performs toner. The image forming apparatus according to claim 1 or 2, wherein it is determined that the collection container needs to be replaced. Equipped with an operation unit that displays messages
The image forming apparatus according to claim 3, wherein the control unit displays a message relating to replacement of the toner recovery container on the operation unit when it is determined that the toner recovery container needs to be replaced. The image forming apparatus according to claim 1 or 2, wherein the control unit changes the threshold value according to the execution frequency and printing rate of image forming performed after mounting the toner collection container. The control unit of the image forming device
A step of detecting the attachment of a replenishment toner container that accommodates each type of toner corresponding to any of the process units that form different types of toner images, and
A step of detecting the attachment of a toner recovery container containing toner that is recovered without being transferred in image formation in which a toner image is formed using the process unit and transferred to paper, and
When the number of replenishment toner containers used after the new toner recovery container is installed exceeds the threshold value set in advance for each type, the step of determining that the toner recovery container needs to be replaced and the step
A method for detecting a full state of a toner recovery container provided with.

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