JP7484692B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device, and is suitable for use in, for example, electrophotographic printers.

Conventionally, in image forming devices using electrophotographic processes such as printers, copiers, facsimile machines, and multifunction machines, there are known image forming devices that have a developer storage unit that is detachable from the image forming device, a transport path for transporting the developer from the developer storage unit to the image forming unit, and a vibration applying means that applies vibration to the transport path to prevent clogging of the developer in the transport path (see, for example, Patent Document 1).

JP 2017-58434 A

However, in such image forming devices, vibrations may be applied during printing operations, and the vibrations may be transmitted to the image forming unit, causing a loss of image quality. Therefore, there is a need to prevent developer clogging while maintaining image quality.

The present invention was made in consideration of the above points, and aims to propose an image forming device that can suppress developer clogging while maintaining image quality.

In order to solve this problem, the image forming device of the present invention includes an image forming unit having a developer storage section that stores developer, a developer storage section that stores developer and discharges it from an outlet, a developer supply connection section through which developer passes from the outlet toward the developer storage section, a vibration imparting mechanism that imparts vibration to at least a part of the developer supply connection section, developer consumption estimating means that estimates the estimated developer consumption required for the next print job, and a control section that controls the vibration imparting mechanism, and the control section is configured to activate the vibration imparting mechanism when the value of the estimated developer consumption becomes equal to or exceeds a threshold value.

When it is expected that the amount of developer supplied from the developer storage section to the image forming unit will be large, the present invention operates the vibration mechanism beforehand before the printing operation to vibrate the developer supply connection section, shaking off the developer adhering to the inner wall surface of the developer supply connection section and creating a situation in which the developer is less likely to become clogged, thereby reducing the number of times that an operation to clear developer clogs is required during the printing operation.

The present invention makes it possible to realize an image forming device that can suppress developer clogging while maintaining image quality.

FIG. 1 is a left side view showing a configuration of an image forming apparatus according to first, second and fourth embodiments. FIG. 2 is a left side view showing the configuration of the image forming unit. 1A and 1B show the configuration of a toner supply connection portion, and FIG. 1A is a cross-sectional view taken along the line A-A in FIG. FIG. 4 is a left side view showing the vertical movement mechanism and the vertical movement of the image forming unit. 2 is a block diagram showing a control configuration of the image forming apparatus according to the first embodiment; FIG. 6 is a flowchart showing a toner clogging removal process according to the first embodiment; FIG. 11 is a block diagram showing a control configuration of an image forming apparatus according to a second embodiment. FIG. 13 is a block diagram showing a resolution determination table. 10 is a flowchart showing a toner clogging removal process according to a second embodiment; FIG. 13 is a left side view showing a configuration of an image forming apparatus according to a third embodiment. FIG. 13 is a block diagram showing a control configuration of an image forming apparatus according to a third embodiment. 13 is a flowchart showing a toner clogging removal process according to a third embodiment. 13 is a flowchart showing a new product replacement detection flag processing procedure according to the third embodiment; FIG. 13 is a block diagram showing a control configuration of an image forming apparatus according to a fourth embodiment. 13 is a flowchart showing a toner clogging removal process according to a fourth embodiment. 13 is a flowchart showing a toner supplying process according to a fourth embodiment.

Below, the form for implementing the invention (hereinafter referred to as embodiment) will be explained with reference to the drawings.

1. First embodiment
[1-1. Configuration of Image Forming Apparatus]
1, the image forming apparatus 1 is, for example, a printer using an electrophotographic method, and performs an image forming operation using a developer such as toner to form a black-and-white image or a color image on a medium P such as paper or film. In the following, a position close to the medium storage tray 2 as viewed from an arbitrary position on the transport path along which the medium P is transported, or a direction toward the medium storage tray 2, is referred to as upstream. Also, a position close to the medium accumulation tray 18 onto which the medium P is discharged and loaded, or a direction toward the medium accumulation tray 18, as viewed from an arbitrary position on the transport path, is referred to as downstream. Furthermore, the direction from upstream to downstream is referred to as the transport direction.

The media storage tray 2 is removably attached to the bottom of the housing of the image forming device 1 and stores media P in a stacked state. The pickup roller 4 separates and removes the media P stored in the media storage tray 2 one by one from the top, and pays it out along the media transport path 3 toward the transport roller pair 5a located downstream. The transport roller pairs 5a and 5b clamp and transport the media P paid out from the pickup roller 4, and transport it along the transport direction toward the transfer unit 6.

The transfer unit 6 as a transfer member has a transfer belt 7, a belt support roller 8, a belt drive roller 9, and a transfer roller 10. The transfer belt 7 is an endless belt, and is stretched by the belt drive roller 9 and the belt support roller 8. The belt drive roller 9 is rotated by a motor (not shown), and rotates the transfer belt 7 counterclockwise in FIG. 1. The belt support roller 8 is a driven roller, and rotates together with the transfer belt 7. As a result, while the toner image is transferred to the medium P by the image forming units 12 (12K, 12C, 12M, and 12Y), the transfer unit 6 rotates the transfer belt 7, and transports the medium P, which has been transported along the medium transport path 3, along the medium transport path 3 to the fuser unit 17.

Image forming units 12K, 12C, 12M, and 12Y are arranged in order along the transport direction from the upstream side to the downstream side, and form developer images (toner images) on medium P using toners (developers) of different colors. Specifically, image forming units 12K, 12C, 12M, and 12Y form black, cyan, magenta, and yellow toner images using black, cyan, magenta, and yellow toners, respectively. Image forming units 12K, 12C, 12M, and 12Y have the same configuration except that they form toner images using toners of different colors, black, cyan, magenta, and yellow, respectively. Hereinafter, image forming units 12K, 12C, 12M, and 12Y are collectively referred to as image forming units 12.

Toner cartridges 13K, 13C, 13M, and 13Y are provided above the image forming units 12K, 12C, 12M, and 12Y, respectively. The toner cartridges 13K, 13C, 13M, and 13Y as developer cartridges have the same configuration except that they contain toner of different colors, black, yellow, magenta, and cyan, respectively. Hereinafter, the toner cartridges 13K, 13C, 13M, and 13Y are also collectively referred to as toner cartridges 13. The toner cartridges 13 (13K, 13C, 13M, and 13Y) contain toner of each color, discharge the toner from an outlet, and supply the toner to the image forming unit 12 via a toner supply duct 14 (14K, 14C, 14M, and 14Y).

Toner supply ducts 14K, 14C, 14M, and 14Y are connected to the toner cartridges 13K, 13C, 13M, and 13Y, respectively. The toner supply ducts 14K, 14C, 14M, and 14Y have the same configuration, except that they transport toner of different colors, black, cyan, magenta, and yellow, respectively. Hereinafter, the toner supply ducts 14K, 14C, 14M, and 14Y are collectively referred to as the toner supply duct 14. The toner supply duct 14 transports the toner discharged from the toner cartridge 13 to the image forming unit 12.

As shown in FIG. 3, a toner transport spiral 15 is installed in each toner supply duct 14. This toner transport spiral 15 is driven to rotate by a toner supply motor 43 (FIG. 5) to transport toner from the toner cartridge 13 to the toner supply connection 26.

Transfer rollers 10 (Fig. 1) are provided for each of the image forming units 12K, 12C, 12M, and 12Y, and are arranged in a manner to face the photosensitive drums 21 (Fig. 2) of the image forming units 12K, 12C, 12M, and 12Y across the transfer belt 7. The transfer rollers 10 have substantially the same configuration. The transfer rollers 10 electrostatically transfer the toner images of each color formed in the image forming units 12K, 12C, 12M, and 12Y onto the medium P. In addition, the image forming units 12C, 12M, and 12Y, including their respective photosensitive drums 21, other than the image forming unit 12K, are spaced a certain distance above the respective transfer rollers 10 by moving upward from the respective transfer rollers 10, i.e., from the transfer section 6, during monochrome printing.

The toner image formed on the photosensitive drum 21 is transferred to the medium P transported by the transfer belt 7 on the medium transport path 3. The fixing unit 17 applies heat and pressure to the toner image on the medium P transported from the transfer belt 7, fixing the toner image to the medium P, and sends it along the medium transport path 3 toward the transport roller pair 5c. The transport roller pairs 5c, 5d, and 5e clamp and transport the medium P, and discharge and collect it on the medium collection tray 18 formed on the top surface of the housing.

[1-2. Configuration of Image Forming Unit]
As shown in FIG. 2, each image forming unit 12 mainly includes a toner container 20, a charging roller (not shown), a developing roller 19, a photosensitive drum 21, an LED (Light Emitting Diode) head 22, a cleaning blade 23, and the like.

The toner storage section 20 is a container that stores the toner of each color described above. That is, black toner, cyan toner, magenta toner, and yellow toner are stored in the toner storage section 20 of each of the image forming units 12K, 12C, 12M, and 12Y. This toner storage section 20 stores the toner supplied from the toner cartridge 13 via the toner supply duct 14 (Figure 3).

The photosensitive drum 21, which serves as an image carrier, is a member that carries an electrostatic latent image on its surface (surface layer), and is constructed using a photosensitive body. The LED head 22 irradiates and exposes the surface of the photosensitive drum 21 with light, thereby forming an electrostatic latent image on the surface of the photosensitive drum 21. One end of the cleaning blade 23 contacts the surface of the photosensitive drum 21, and scrapes off toner that remains on the surface of the photosensitive drum 21 without being transferred to the medium P.

In addition, cylindrical support shafts 24 protrude outward from both the left and right ends of the image forming unit 12. A vertical movement mechanism 28 (FIG. 4), which will be described later, slides on the support shaft 24 of each image forming unit 12. Furthermore, each image forming unit 12 is provided with a toner sensor 25 that detects the amount of toner remaining in the image forming unit 12.

[1-3. Configuration of toner supply connection part]
3, a toner supply connection 26 is provided at the connection between the image forming unit 12 and the toner supply duct 14. This toner supply connection 26 connects the image forming unit 12 and the toner supply duct 14, and functions as a transport path for transporting toner from the toner cartridge 13 to the image forming unit 12, causing the toner to pass through an internal space and fall by gravity into the image forming unit 12. In addition, the end of the toner supply duct 14 opposite to the toner supply connection 26 is connected to the outlet of the toner cartridge 13 of the corresponding color.

The toner supply connection part 26 is composed of a duct side connection part 26a and a unit side connection part 26b, and is formed, for example, from a hard resin molding. The duct side connection part 26a as a first member is located at the upper part of the toner supply connection part 26, has a hollow cylindrical shape with an open top and bottom surface and a central axis along the vertical direction, and its upper end is fixed to an opening drilled in the bottom surface of the toner supply duct 14. The unit side connection part 26b as a second member is located at the lower part of the toner supply connection part 26, has a hollow cylindrical shape with an open top and bottom surface and a central axis along the vertical direction, and its lower end is fixed to an opening drilled in the upper surface of the housing of the image forming unit 12. The unit side connection part 26b is formed so that its inner diameter is almost the same as the outer diameter of the duct side connection part 26a, and the lower end of the duct side connection part 26a is inserted into the internal space from the upper end to the lower side. The toner transported from the toner cartridge 13 to the toner supply connection part 26 by the toner transport spiral 15 passes through the duct side connection part 26a and the unit side connection part 26b of the toner supply connection part 26 in sequence, and falls into the image forming unit 12, where it is supplied to the toner storage part 20 of the image forming unit 12.

The unit side connection part 26b is configured to be movable in the vertical direction while sliding relative to the duct side connection part 26a on the outer periphery side of the duct side connection part 26a. Therefore, when the image forming unit vertical movement operation described below is performed and the image forming unit 12 moves in the vertical direction, the unit side connection part 26b moves back and forth in the vertical direction relative to the duct side connection part 26a.

[1-4. Configuration of the vertical movement mechanism]
As shown in Fig. 4, each image forming unit 12 is provided with a vertical movement mechanism 28 that is driven independently of the other. The vertical movement mechanism 28, which serves as a moving mechanism or a contact mechanism, is composed of an elliptical cam 28a and a lift-up motor 28m that drives the elliptical cam 28a. The elliptical cam 28a can be rotated by the driving force of the lift-up motor 28m about a rotation axis that extends in the left-right direction directly below the support shaft 24, and is disposed so that its outer circumferential surface slides against the support shaft 24 at a position that sandwiches the image forming unit 12 from the left-right direction.

When the lift-up motor 28m is driven under the control of the motor control unit 42 (FIG. 5), the elliptical cam 28a rotates. As shown in FIG. 4A, when the upper end of the elliptical cam 28a in the long axis direction abuts against the underside of the support shaft 24, the elliptical cam 28a pushes up the support shaft 24. This causes the elliptical cam 28a to move the image forming unit 12 along a guide rail (not shown) so as to lift it up to a raised position. When the elliptical cam 28a further rotates and the long axis direction of the elliptical cam 28a is aligned horizontally (i.e., the upper end of the short axis direction abuts against the support shaft 24) as shown in FIG. 4B, the elliptical cam 28a pushes down the support shaft 24. This causes the elliptical cam 28a to move the image forming unit 12 along a guide rail (not shown) so as to lift it down to a lowered position.

In this way, the image forming device 1 controls the vertical movement mechanism 28 provided for each image forming unit 12 to move each image forming unit 12 up and down between the upper position and the lower position while keeping the image forming unit 12 horizontal. Hereinafter, this operation is also referred to as the image forming unit vertical movement operation. While the image forming unit 12 is in the upper position, the photosensitive drum 21 of the image forming unit 12 is separated from the transfer belt 7. On the other hand, while the image forming unit 12 is in the lower position, the photosensitive drum 21 of the image forming unit 12 is in contact with the transfer belt 7. When the image forming unit 12 moves between the upper position and the lower position, the relative distance between the image forming unit 12 and the toner supply duct 14 changes. This change in relative distance is absorbed by the unit side connection part 26b moving up and down relative to the duct side connection part 26a and the toner supply connection part 26 deforming. In this way, the vertical movement mechanism 28 as a contact and separation mechanism contacts and separates the image forming unit 12 with respect to the transfer roller 10 in the transfer part 6 as a transfer member. In other words, the vertical movement mechanism 28, which serves as a movement mechanism, moves the image forming unit 12 relative to the transfer roller 10 in the transfer section 6, which serves as a transfer member.

In addition, during printing operations, the image forming device 1 moves the image forming units 12 corresponding to the colors not used in printing to a raised position as a non-image forming position, thereby separating them from the transfer belt 7, and avoids unnecessary wear and deterioration in image quality due to the transfer of unnecessary toner remaining on the photosensitive drum 21. That is, for example, during monochrome printing, the image forming device 1 moves only the image forming unit 12K to a lowered position as an image forming position, and moves the image forming units 12C, 12M, and 12Y not used for monochrome printing to the raised position and separated them from the transfer belt 7.

[1-5. Control configuration of image forming apparatus]
5, the image forming apparatus 1 has a device control section 30. The device control section 30 is configured with a CPU (Central Processing Unit), and reads out a predetermined program from a storage section 36 to centrally control the image forming apparatus 1. The device control section 30 has a motor drive section 31, an image forming unit vertical position detection section 32, a print information receiving section 33, a data analysis section 34, a storage section 36, and a toner remaining amount detection section 40.

The motor driving means 31 drives the toner supply motor 43 and the lift-up motor 28m by controlling the motor control section 42. The image forming unit vertical position detection means 32 obtains the vertical position of the image forming unit 12 from the vertical movement mechanism 28 by controlling the image forming unit vertical position detection section 44.

The printing information receiving unit 33 receives printing information from a higher-level device. The data analyzing unit 34 analyzes the printing information received by the printing information receiving unit 33 and estimates the estimated toner consumption. Specifically, each time a page is printed, the data analyzing unit 34 calculates the estimated toner consumption, which is the amount of toner that is thought to be actually consumed during printing, from the number of pixels (number of dots) per page.

The storage means 36 stores the estimated toner supply amount counter 37 of the toner cartridge 13. The estimated toner supply amount counter 37 is a cumulative value of the estimated toner consumption amount for each toner cartridge 13 from when the toner cartridge 13 is replaced with a new one to the present. This estimated toner supply amount counter is set to 0 when the toner cartridge 13 is replaced with a new one. The toner remaining amount detection means 40 detects the remaining amount of toner in the image forming unit 12 from the output of the toner sensor 25 by controlling the toner remaining amount detection section 45.

[1-6. Toner clogging elimination process]
A specific procedure for the toner clogging elimination process by the image forming apparatus 1 will be described with reference to the flow chart of FIG. 6. The device control unit 30 starts the toner clogging elimination process procedure RT1 by reading and executing the toner clogging elimination process program from the storage means 36, and proceeds to step SP1. In step SP1, the device control unit 30 judges whether or not the toner sensor 25 detects toner low before or during the printing operation. Here, during the printing operation is the period from the paper feed operation of feeding the medium P from the medium storage tray 2 to the medium transport path 3 to the time when all the print data included in the print information is printed on the medium P and discharged to the medium accumulation tray 18, and before the printing operation is the period before that. If a negative result is obtained here, this indicates that the toner is not low, and therefore the amount of toner in the toner storage unit 20 is equal to or greater than the lower limit, and at this time the device control unit 30 proceeds to step SP14, ends the toner clogging elimination process procedure RT1, and if during the printing operation, proceeds to resume the printing operation.

On the other hand, if a positive result is obtained in step SP1, this indicates that the amount of toner in the toner storage unit 20 has fallen below the lower limit and that it is necessary to perform a toner supply operation to supply toner from the toner cartridge 13 to the toner storage unit 20, and the device control unit 30 then proceeds to step SP2. In step SP2, if a printing operation is in progress, the device control unit 30 stops the new paper feed operation and waits for printing of the pages that have already been fed to finish, thereby interrupting the printing operation, and then proceeds to step SP3. The following describes the case where toner low is detected by the toner sensor 25 of image forming unit 12Y, but the same operation occurs when toner low is detected in image forming units 12 of other colors.

In step SP3, after printing of the pages that have already been fed is completed, the device control unit 30 starts the toner supply operation and proceeds to step SP4. At this time, the device control unit 30 drives the toner supply motor 43 and rotates the toner transport spiral 15 to transport toner from the toner cartridge 13Y to the image forming unit 12Y in the toner supply duct 14, and supplies toner to the image forming unit 12Y.

After continuing the toner supply operation for a certain period of time, in step SP4, the device control unit 30 determines whether or not the toner sensor 25 has detected toner low again. If a negative result is obtained here, this indicates that the toner is no longer low, and the device control unit 30 ends the toner supply operation and proceeds to step SP14, ending the toner clogging removal processing procedure RT1, and proceeds to resuming the printing operation if a printing operation is in progress. On the other hand, if a positive result is obtained in step SP4, this indicates that the toner supply operation was performed but the toner remained low, and therefore a toner clogging may have already occurred, and the device control unit 30 then proceeds to step SP5.

In step SP5, the device control unit 30 determines whether the toner near-end condition is met. In this embodiment, the toner near-end condition is determined based on whether the estimated toner supply amount counter 37 from the time when the toner cartridge 13Y was replaced with a new one until the timing of step SP1 exceeds the toner capacity of the new toner cartridge 13. If a positive result is obtained here, this indicates that the toner low detected in step SP4 is due to the toner cartridge 13Y being empty, since the estimated toner consumption counter exceeds the toner cartridge capacity, and the device control unit 30 then proceeds to step SP6. In step SP6, the device control unit 30 generates a toner near-end status to indicate to the operator that the toner cartridge 13Y should be replaced with a new one when the current printing operation is completed, and proceeds to step SP15, where the toner clogging elimination processing procedure RT1 is terminated and the printing operation is resumed.

On the other hand, if a negative result is obtained in step SP5, this means that the estimated toner supply amount counter 37 is equal to or less than the toner cartridge capacity, and therefore even though there is still toner stored in the toner cartridge 13Y, toner low is detected when the toner supply operation is performed, indicating that a toner blockage may have occurred, and the process proceeds to step SP7.

In step SP7, the device control unit 30 starts driving the lift-up motor 28m to start the operation of moving the image forming unit 12Y up and down, and proceeds to step SP8 while continuing to drive the lift-up motor 28m. In step SP8, the device control unit 30 determines whether the operation of moving the image forming unit up and down has been performed a preset number of times. If a negative result is obtained here, the device control unit 30 repeats step SP8, and when the operation of moving the image forming unit up and down has been performed a preset number of times, a positive result is obtained in step SP8 and the device control unit proceeds to step SP9.

When this image forming unit up and down movement operation is performed repeatedly, the relative position between the toner supply duct 14 connected to the image forming unit 12Y and the image forming unit 12Y changes, and the unit side connection part 26b moves up and down relative to the duct side connection part 26a corresponding to the image forming unit 12Y. This causes the toner supply connection part 26 corresponding to the image forming unit 12Y to repeatedly expand and contract. This causes a deformation force to act on the toner stuck inside the toner supply connection part 26 connected to the image forming unit 12Y, and it is expected that the toner stuck inside the toner supply connection part 26 will peel off and fall off, eliminating the toner clogging.

In step SP9, the device control unit 30 executes the toner supply operation again, and proceeds to step SP10. In step SP10, the device control unit 30 determines whether or not the toner sensor 25 has detected toner low again. If a negative result is obtained here, this indicates that the toner clogging has been cleared, so toner can be supplied from the toner cartridge 13Y to the toner storage section 20 of the image forming unit 12Y, and toner is no longer low. In this case, the device control unit 30 ends the toner supply operation, proceeds to step SP16, ends the toner clogging clearing process procedure RT1, and returns to the printing operation.

On the other hand, if a positive result is obtained in step SP10, this indicates that a toner clog has occurred that cannot be cleared by moving the image forming unit up and down, such as inside the toner supply duct 14Y, and therefore requires action by the operator, and in this case the device control unit 30 proceeds to step SP11. In step SP11, the device control unit 30 generates a toner supply error, proceeds to step SP12, and stops the printing operation, waiting for the operator to correct the malfunction, proceeds to step SP13, and ends the toner clog clearing processing procedure RT1.

[1-7. Effects, etc.]
In the above configuration, the image forming device 1 continuously moves the image forming unit up and down when it detects a toner supply error due to toner low and not satisfying the toner near-end condition before or during the printing operation. This allows the image forming device 1 to clear toner clogging inside the toner supply connection portion 26. This allows the image forming device 1 to clear toner clogging without forcing the operator to perform complicated procedures to clear the toner clogging.

In addition, in the printing operation, the image forming device 1 is configured to perform an image forming unit up and down movement operation using the up and down movement mechanism 28 that has been incorporated since before in order to move the image forming unit 12 corresponding to the color not used for printing to the raised position. Therefore, the image forming device 1 can clear toner clogging by utilizing the up and down movement mechanism 28 that has been incorporated since before, without having to add a separate dedicated part for clearing toner clogging.

2. Second embodiment
[2-1. Control configuration of image forming apparatus]
As shown in FIG. 7 in which the same reference numerals are used for components corresponding to those in FIG. 5, the image forming apparatus 101 according to the second embodiment differs from the image forming apparatus 1 according to the first embodiment in that it has a device control unit 130 instead of the device control unit 30 and that a temperature and humidity sensor 47 has been added, but is otherwise configured in a similar manner.

The device control unit 130 according to the second embodiment has a storage means 136 instead of the storage means 36, and is different in that a temperature and humidity detection means 48 has been added, but is otherwise configured in the same way. The storage means 136 according to the second embodiment stores a clogging removal determination table 49 shown in FIG. 8.

The temperature and humidity detection means 48, which serves as an environmental information detection unit, controls the temperature and humidity sensor 47 to detect the temperature and humidity of the environment in which the image forming device 101 is installed as temperature information and humidity information.

[2-2. Configuration of the clogging elimination determination table]
8, in the jam removal determination table 49, an estimated toner supply amount counter, a supply amount threshold, a humidity threshold, and an execution count coefficient are stored in association with each other for each image forming unit 12. Here, the image forming apparatus 101 in the present embodiment determines, for each image forming unit 12 that performs the image forming unit up-down movement operation, a value obtained by multiplying a specified number of times, which is a reference for the image forming unit up-down movement operation, by the execution count coefficient in the jam removal determination table 49, as the weighted specified number of times, which is the number of times the image forming unit up-down movement operation is actually performed.

The estimated toner supply amount counter is the cumulative value of the estimated toner consumption amount from when the toner cartridge 13 was replaced with a new one to the present. In addition, when the toner cartridge 13 is replaced with a new one, this estimated toner supply amount counter is set to 0, and the estimated toner supply amount counter of the image forming unit 12 in which the image forming unit up/down movement operation has been performed is cleared to 0.

The supply amount threshold is a preset threshold value that is a condition for executing a toner clogging clearing operation for each image forming unit 12. That is, the image forming device 101 executes a toner clogging clearing operation for an image forming unit 12 whose estimated toner supply amount counter is equal to or greater than the supply amount threshold. This supply amount threshold is set to a value with a sufficient margin so that even if the estimated toner supply amount counter reaches the supply amount threshold, the possibility of a toner clogging occurring is still low.

The humidity threshold is a threshold for determining whether or not to multiply the specified number of times serving as the reference for the up-down movement of the image forming unit by the execution count coefficient in the jam removal determination table 49 when calculating the weighted specified number of times. That is, when the humidity information acquired from the temperature and humidity sensor 47 is equal to or greater than the humidity threshold, the image forming device 101 acquires from the removal determination table 49 the execution count coefficient by which to multiply the specified number of times serving as the reference for the up-down movement of the image forming unit. On the other hand, when the humidity information acquired from the temperature and humidity sensor 47 is less than the humidity threshold, the image forming device 101 does not acquire from the removal determination table 49 the execution count coefficient by which to multiply the specified number of times serving as the reference for the up-down movement of the image forming unit, and sets the execution count coefficient to 1.

The execution count coefficient is a preset coefficient that is multiplied by the specified number of times when the humidity information is equal to or greater than the humidity threshold value to calculate a weighted specified number of times that is greater than the specified number.

In this way, for image forming units 12 whose humidity information is equal to or greater than the humidity threshold, the image forming device 101 performs the image forming unit up-down movement operation a number of times greater than the specified number of times that is the standard for the image forming unit up-down movement operation.

[2-3. Conditions for clearing toner jams]
When an image forming unit 12 that satisfies the toner clogging removal operation execution condition is present, image forming apparatus 101 executes a toner clogging removal operation for that image forming unit 12. This toner clogging removal operation execution condition is determined based on whether or not an estimated toner supply amount counter stored in clogging removal determination table 49 is equal to or greater than a supply amount threshold stored in clogging removal determination table 49. If the estimated toner supply amount counter is equal to or greater than the supply amount threshold, the toner clogging removal operation execution condition is satisfied.

For example, when printing that consumes a lot of toner, such as high-duty printing (printing with high print image density) or high-speed printing, is continued, the amount of toner supplied increases, resulting in a higher probability of toner clogging. For this reason, the image forming device 101 sets the condition for performing a toner clogging removal operation as being when the estimated toner supply amount counter is equal to or greater than the supply amount threshold. Here, print image density is a value that represents the proportion of pixels to which toner is transferred to the medium P out of the total number of pixels when an image is broken down into pixel units.

Before starting a printing operation, the image forming device 101 compares the estimated toner supply amount counter with the supply amount threshold in all image forming units 12 to determine whether there is an image forming unit 12 that satisfies the conditions for executing a toner clogging removal operation. Hereinafter, an image forming unit 12 that satisfies the conditions for executing a toner clogging removal operation and is the target for performing an image forming unit up/down movement operation is also referred to as a target image forming unit. The image forming device 101 performs an image forming unit up/down movement operation for all target image forming units.

As shown in the resolution determination table 49 (Figure 8), the supply amount threshold is preset for each image forming unit 12. This is because there may be bias in the likelihood of toner clogging depending on the characteristics of the toner material, the length and shape of the toner supply duct 14, etc.

In this embodiment, the image forming device 101 uses the estimated toner supply amount counter from the previous toner clogging clearing operation as the condition for determining whether to perform the toner clogging clearing operation. However, until the first toner clogging clearing operation is performed after the toner cartridge 13 is replaced with a new one, the image forming device 101 uses the estimated toner supply amount counter from when the toner cartridge 13 is replaced with a new one as the condition for determining whether to perform the toner clogging clearing operation.

[2-4. Toner clogging elimination process]
A specific procedure for the toner clogging removal process by the image forming apparatus 101 will be described with reference to the flowchart in Fig. 9. The apparatus control unit 130 starts the toner clogging removal process procedure RT101 by reading and executing a toner clogging removal process program from the storage means 136, and proceeds to step SP101. In step SP101, the apparatus control unit 130 judges whether or not there is an image forming unit 12 that satisfies the toner clogging removal operation execution conditions before the start of the printing operation. If a negative result is obtained here, this indicates that there is no image forming unit 12 that satisfies the toner clogging removal operation execution conditions, and therefore it is not necessary to perform the toner clogging removal operation in all image forming units 12, and in this case the apparatus control unit 130 proceeds to step SP107, ends the toner clogging removal process procedure RT101, and starts the printing operation.

On the other hand, if a positive result is obtained in step SP101, this indicates that an image forming unit 12 exists that satisfies the conditions for performing the toner clogging removal operation, and therefore it is necessary to perform the toner clogging removal operation in at least one of the target image forming units 12, and in this case the device control unit 130 proceeds to step SP102.

In step SP102, the device control unit 130 acquires humidity information from the temperature and humidity sensor 47, and proceeds to step SP103. In step SP103, the device control unit 130 compares the acquired humidity information with the humidity threshold value of the target image forming unit in the jam removal determination table 49, and acquires the execution count coefficient.

For example, assume that the target image forming units are image forming units 12Y and 12M, and the humidity information is a humidity of 52%. In this case, the humidity of 52% in the humidity information is equal to or greater than the humidity threshold value of 50% for image forming unit 12Y in the jam removal determination table 49. Therefore, the device control unit 130 obtains 1.5 from the execution count coefficient of image forming unit 12Y in the jam removal determination table 49, and determines the execution count coefficient to be 1.5. On the other hand, the humidity of 52% in the humidity information is smaller than the humidity threshold value of 55% for image forming unit 12M in the jam removal determination table 49. Therefore, the device control unit 130 does not obtain a numerical value from the execution count coefficient of image forming unit 12M in the jam removal determination table 49, and determines the execution count coefficient to be 1, assuming that there is no execution count coefficient.

For this reason, if the standard number of times for the image forming unit up-down movement operation is, for example, 10 times, the device control unit 130 determines for image forming unit 12Y, 10 times multiplied by the execution count coefficient of 1.5, to be 15 times, which is the weighted specified number of times that the image forming unit up-down movement operation will actually be performed. On the other hand, for image forming unit 12M, the device control unit 130 determines, for image forming unit 12M, 10 times multiplied by the execution count coefficient of 1, to be 10 times, which is the weighted specified number of times that the image forming unit up-down movement operation will actually be performed.

In step SP104, the device control unit 130 starts the operation of moving the image forming unit up and down of the target image forming unit by starting the driving of the lift-up motor 28m, and proceeds to step SP105 while continuing the driving of the lift-up motor 28m. In step SP105, the device control unit 130 judges for each target image forming unit whether the image forming unit up and down movement operation has been performed the specified number of times after weighting calculated for each target image forming unit in step SP103. If a negative result is obtained here, this indicates that there is a target image forming unit that has not yet performed the image forming unit up and down movement operation the specified number of times after weighting, and in this case, the device control unit 130 repeats step SP105, and when the image forming unit up and down movement operation has been performed the specified number of times after weighting set for all target image forming units, a positive result is obtained in step SP105 and proceeds to step SP106. In the image forming apparatus 101 according to this embodiment, the vertical movement mechanisms 28 of all image forming units 12 are independently movable, so the vertical movement of the image forming units in all target image forming units is performed simultaneously.

In step SP106, the device control unit 130 clears to 0 the estimated toner supply amount counter in the storage unit 136 that corresponds to the image forming unit 12 that performed the image forming unit up/down movement operation, and proceeds to step SP107, terminating the toner clogging clearing process procedure RT101, and starting the printing operation. Note that if the image forming device 101 detects toner low after the start of the printing operation, it executes the same process as the toner clogging clearing process procedure RT1 (FIG. 6) in the image forming device 1 according to the first embodiment.

[2-5. Effects, etc.]
In the above configuration, the image forming apparatus 101 performs an image forming unit up/down movement operation for the image forming unit 12 in which the estimated toner supply amount counter is equal to or greater than the supply amount threshold. This allows the image forming apparatus 101 to preventively eliminate toner clogging before it occurs. This allows the image forming apparatus 101 to reduce the situation in which a toner supply operation is attempted, followed by a toner clogging elimination operation, and then a toner supply is performed again, as in the image forming apparatus 1 of the first embodiment. Thus, compared to the image forming apparatus 1, the image forming apparatus 101 can more easily avoid the occurrence of a situation in which a printing operation must be interrupted in order to perform a toner clogging elimination operation.

In addition, the image forming device 101 sets a different supply amount threshold for each image forming unit 12 in the clogging removal determination table 49 depending on the susceptibility of toner clogging. This allows the image forming device 101 to set the frequency of performing the toner clogging removal operation individually for each image forming unit 12. This allows the image forming device 101 to reduce the frequency of performing the toner clogging removal operation.

Here, toner clogging tends to occur more easily when the environmental humidity is high. In response to this, the image forming device 101 performs the up-down movement operation of the image forming unit a specified number of times after weighting the number of times that is greater than the specified number that serves as the basis for the up-down movement operation of the image forming unit for the target image forming unit whose humidity information is equal to or greater than the humidity threshold value.

Here, when the image forming unit is moved up and down a specified number of times after weighting, the image forming device 101 moves the image forming unit up and down for a longer period of time than when the image forming unit is moved up and down a specified number of times. That is, the image forming device 101 sets a time for performing the image forming unit up and down movement operation a specified number of times as a first time for operating the up and down movement mechanism 28 when the humidity value is less than the humidity threshold value as a predetermined first value, and a time for performing the image forming unit up and down movement operation a specified number of times after weighting as a second time that is greater than or equal to the first time for operating the up and down movement mechanism 28 when the humidity value is equal to or greater than the humidity threshold value as a second value that is greater than the first value.

In this way, the image forming device 101 can more reliably eliminate toner clogging under conditions where toner clogging is likely to occur by changing the number of times the image forming unit moves up and down in response to the humidity information.

In addition, the image forming device 101 according to the second embodiment can achieve the same effects as the image forming device 1 according to the first embodiment.

3. Third embodiment
[3-1. Configuration of Image Forming Apparatus]
10 in which the same reference numerals are used for members corresponding to those in Fig. 1, and Fig. 11 in which the same reference numerals are used for members corresponding to those in Fig. 5, an image forming apparatus 201 according to the third embodiment is different from the image forming apparatus 1 according to the first embodiment in that it has a device control unit 230 instead of the device control unit 30, and that it additionally has RFID chips 52K, 52C, 52M, and 52Y, an attachment/detachment sensor 53, a toner attachment detection unit 54, and an RFID communication unit 55, but is otherwise configured similarly. Hereinafter, the RFID chips 52K, 52C, 52M, and 52Y will also be collectively referred to as RFID chips 52.

RFID chips 52K, 52C, 52M and 52Y are attached to toner cartridges 13K, 13C, 13M and 13Y, respectively, and store information such as the model of the image forming device 201 that the attached toner cartridge 13 is compatible with, its capacity, and a new product flag.

[3-2. Control configuration of image forming apparatus]
The device control unit 230 according to the third embodiment has a storage unit 236 instead of the storage unit 36, and is different in that an RFID reader 56 and a toner cartridge attachment detector 57 are added, but otherwise configured similarly. The storage unit 236 according to the third embodiment stores a new cartridge replacement detection flag 59 and a toner consumption threshold 61. The new cartridge replacement detection flag 59 is a flag that is set for each toner color when it is detected that the toner cartridge 13 has been replaced with a new one. The toner consumption threshold 61 is a preset threshold that is a condition for performing a toner clogging removal operation for each image forming unit 12. That is, the image forming device 201 performs a toner clogging removal operation for an image forming unit 12 whose estimated toner consumption is equal to or greater than the toner consumption threshold.

The RFID reading means 56 controls the RFID communication unit 55 to read out the RFID chip information, which is the information on the RFID chip 52 of the toner cartridge 13. The attachment/detachment sensor 53 detects the attachment/detachment of the toner cartridge 13, and sends the detection result to the toner attachment detection unit 54. The toner cartridge attachment detection means 57, which serves as a developer cartridge attachment detection means, controls the toner attachment detection unit 54 to obtain information from the attachment/detachment sensor 53 and detect whether the toner cartridge 13 is attached or not.

[3-3. Toner clogging elimination process]
A specific procedure for the toner clogging clearing process by the image forming apparatus 201 will be described with reference to the flowchart in Fig. 12. When the apparatus control unit 230 receives print information from a higher-level apparatus, it reads out a toner clogging clearing process program from the storage means 236 and executes it to start the toner clogging clearing process procedure RT201, and then proceeds to step SP201. In this embodiment, it is determined whether or not to perform the toner clogging clearing process before the start of a printing operation, and the conditions for this determination are the estimated toner consumption amount required for the print data to be printed and whether or not the toner cartridge has been replaced.

In step SP201, before starting a printing operation, the device control unit 230 checks the value of the new cartridge replacement detection flag 59 stored in the storage means 236, and determines whether or not there is a toner cartridge 13 for which the new cartridge replacement detection flag 59 is set. If a positive result is obtained here, this indicates that it is necessary to perform a toner clogging removal operation because this is the first printing operation since detecting the most recent replacement of the toner cartridge 13, and the device control unit 230 then proceeds to step SP202.

Here, immediately after replacing the toner cartridge 13, a large amount of toner tends to pass through the toner supply connection portion 26, making toner clogging likely to occur. For this reason, immediately after replacing a new toner cartridge 13, the image forming device 201 executes a toner clogging clearing operation even if the estimated toner consumption is less than the toner consumption threshold 61. In step SP202, the device control unit 230 clears the new product replacement detection flag 59 for the toner cartridge 13 for which the new product replacement detection flag 59 was set, and proceeds to step SP203. In step SP203, the device control unit 230 sets a toner clogging clearing operation execution flag, which is a temporary flag used to determine whether or not to perform a toner clogging clearing operation, for each image forming unit 12 corresponding to the toner cartridge 13 for which the new product replacement detection flag 59 was set, and proceeds to step SP204.

On the other hand, if a negative result is obtained in step SP201, this indicates that since this is not the first printing operation after the most recent replacement of the toner cartridge 13 has been detected, if the estimated toner consumption is less than the toner consumption threshold (described later), there is no need to perform a toner clogging removal operation, and in this case, the device control unit 230 skips steps SP202 and SP203 and proceeds to step SP204. In step SP204, the device control unit 230 calculates the estimated toner consumption for each image forming unit 12 from the number of pixels at the stage when image data for forming a toner image is generated from the print data included in the print information by the data analysis unit 34, and proceeds to step SP205. The print information from the upper device is sent to the image forming device 201 in sequence according to the progress of the print operation. For this reason, there is a possibility that image data for all pages will not be available in the image forming device 201 before the start of the print operation. For this reason, it is difficult for the image forming device 201 to predict the toner consumption of the entire print data. In response to this, the image forming device 201 uses print data that has already been received before starting the first paper feed operation as the target for toner consumption prediction.

In step SP205, the device control unit 230 determines whether there is an image forming unit 12 whose estimated toner consumption is equal to or greater than the toner consumption threshold. If a positive result is obtained here, this indicates that the print data about to be printed will consume a large amount of toner and therefore it is necessary to perform a preventive toner clogging removal operation, and the device control unit 230 then proceeds to step SP206. In step SP206, the device control unit 230 sets a toner clogging removal operation execution flag, which is a temporary flag used to determine whether or not to perform a toner clogging removal operation, for each image forming unit 12 whose estimated toner consumption is equal to or greater than the toner consumption threshold, and proceeds to step SP207.

On the other hand, if a negative result is obtained in step SP205, this indicates that the print data to be printed does not consume a large amount of toner, and therefore there is no need to perform preventative toner clogging removal operations unless the toner cartridge 13 has just been replaced with a new one, and in this case the device control unit 230 proceeds to step SP207.

In step SP207, the device control unit 230 determines whether there is an image forming unit 12 for which the toner clogging clearing operation execution flag is set. If a negative result is obtained here, this indicates that the print data to be printed does not consume a large amount of toner, and it is not immediately after replacing the toner cartridge 13 with a new one, so there is no need to perform a preventative toner clogging clearing operation. In this case, the device control unit 230 proceeds to step SP210, ends the toner clogging clearing processing procedure RT201, and starts the printing operation.

On the other hand, if a positive result is obtained in step SP207, this indicates that the print data to be printed will consume a large amount of toner, or the toner cartridge 13 has just been replaced with a new one, or both, and therefore there is a target image forming unit 12 that requires preventive toner clogging removal operations to be performed, and in this case the device control unit 230 proceeds to step SP208.

In step SP208, the device control unit 230 starts the operation of moving the image forming unit up and down of the target image forming unit by starting the driving of the lift-up motor 28m, and proceeds to step SP209 while continuing to drive the lift-up motor 28m. In step SP209, the device control unit 230 judges for each target image forming unit whether the image forming unit up and down movement operation has been performed a preset number of times. If a negative result is obtained here, this indicates that there is a target image forming unit that has not yet performed the image forming unit up and down movement operation the specified number of times. In this case, the device control unit 230 repeats step SP209, and when the image forming unit up and down movement operation has been performed the specified number of times for each target image forming unit, a positive result is obtained in step SP209, and the device control unit 230 proceeds to step SP211, ends the toner clogging elimination processing procedure RT201, and starts the printing operation. In the image forming device 201 according to this embodiment, the vertical movement mechanisms 28 of all image forming units 12 are independently movable, so the vertical movement of the image forming units in all target image forming units is performed simultaneously.

[3-4. New replacement detection flag processing]
A specific procedure for the new cartridge replacement detection flag processing by the image forming apparatus 201 will be described with reference to the flowchart in Fig. 13. When the attachment/detachment sensor 53 detects that any of the toner cartridges 13 has been removed from the image forming apparatus 201 by the operator, the apparatus control unit 230 reads out a new cartridge replacement detection flag processing program from the storage unit 236 and executes it to start a new cartridge replacement detection flag processing procedure RT301, and then proceeds to step SP301.

This new toner cartridge replacement detection flag processing procedure RT202 is a process for setting the new toner cartridge replacement detection flag 59 used in the toner clogging removal processing procedure RT201 (FIG. 12) described above. This new toner cartridge replacement detection flag 59 is set when it is detected that the toner cartridge 13 has been replaced.

In step SP301, the device control unit 230 determines whether the toner cartridge 13 has been re-installed by the operator based on the detection result from the installation/removal sensor 53. If a negative result is obtained, the device control unit 230 proceeds to step SP302. In step SP302, the device control unit 230 displays a toner not installed error on a specified display unit to prompt the operator to re-install the toner cartridge 13, and then returns to step SP301. Thereafter, steps SP301 and SP302 are repeated, and the device control unit 230 waits until the toner cartridge 13 is re-installed.

When the toner cartridge 13 is reinstalled by the operator, the device control unit 230 obtains a positive result in step SP301 and proceeds to step SP303. In step SP303, the device control unit 230 reads the RFID chip information from the RFID chip 52 of the reinstalled toner cartridge 13 via the RFID communication unit 55, and proceeds to step SP304.

In step SP304, the device control unit 230 determines whether the information in the RFID chip 52 is valid. If a negative result is obtained here, this indicates that the RFID chip information is invalid, such as that the RFID chip information cannot be read from the RFID chip 52 or is not compatible with the image forming device 201, and in this case the device control unit 230 proceeds to step SP305. In step SP305, the device control unit 230 displays a toner cartridge error on a specified display unit, indicating that an abnormality has occurred in the toner cartridge 13, proceeds to step SP308, and ends the new product replacement detection flag processing procedure RT301.

On the other hand, if a positive result is obtained in step SP304, this indicates that the RFID chip information is valid, and the device control unit 230 then proceeds to step SP306. In step SP306, the device control unit 230 checks the RFID chip information and determines whether the installed toner cartridge 13 is new. If a negative result is obtained here, this indicates that the toner cartridge 13 is not new, for example, when a toner cartridge 13 that was once removed from the image forming device 201 is installed as is, and therefore there is no need to perform a toner clogging removal operation in the above-mentioned toner clogging removal processing procedure RT201 due to the installation of a new toner cartridge 13. In this case, the device control unit 230 does not set the new product replacement detection flag 59, proceeds to step SP309, and ends the new product replacement detection flag processing procedure RT202.

On the other hand, if a positive result is obtained in step SP306, this indicates that the installed toner cartridge 13 is new, and therefore in the above-mentioned toner clogging clearing processing procedure RT201, it is necessary to perform a toner clogging clearing operation due to the installation of a new toner cartridge 13, and at this time the device control unit 230 proceeds to step SP307. In step SP307, the device control unit 230 sets the new product replacement detection flag 59 corresponding to the toner color of the installed new toner cartridge 13, proceeds to step SP310, and ends the new product replacement detection flag processing procedure RT301. Thereafter, the device control unit 230 performs processing to use the new toner cartridge 13, such as updating the remaining toner amount status.

[3-5. Effects, etc.]
In the above configuration, the image forming device 201 performs an image forming unit up/down movement operation in the image forming unit 12 in which the estimated toner consumption amount of the print data to be printed next is equal to or greater than the toner consumption amount threshold 61. Therefore, in the image forming device 201, it is assumed that a large amount of toner will pass through the toner supply connection portion 26 in the print data to be printed next, and in the case of usage conditions in which toner clogging is likely to occur, the toner currently adhering to the inside of the toner supply connection portion 26 can be removed in advance by preventively performing a toner clogging clearing operation before starting the printing operation.

In addition, the image forming device 201 is configured to perform an up-down movement operation of the image forming unit 12 in which the toner cartridge 13 is installed before a printing operation is performed after a new toner cartridge 13 is installed. Therefore, when the image forming device 201 is about to print, it is assumed that a large amount of toner will pass through the toner supply connection portion 26 from the new toner cartridge 13, and in a usage situation in which toner clogging is likely to occur, the toner currently adhering to the inside of the toner supply connection portion 26 can be removed in advance by preventively performing a toner clogging clearing operation before starting a printing operation.

As a result, the image forming device 201 can reduce the occurrence of opportunities for vibration to be applied to the image forming unit 12 by performing an image forming unit up and down movement operation during printing operation after the start of the paper feed operation. In this way, the image forming device 201 is required to prevent vibration from being applied to the image forming unit 12 during printing operation and to reduce developer clogging while maintaining image quality.

This also eliminates the need for the image forming device 201 to temporarily halt printing operations to clear a toner clog that occurs during printing operations. In this way, the image forming device 201 can prevent a decrease in productivity caused by interrupting printing operations to clear a toner clog, and can improve the productivity of printing operations.

According to the above configuration, the image forming device 201 includes an image forming unit 12 having a toner storage section 20 as a developer storage section that stores toner as a developer, a toner cartridge 13 that stores toner and discharges it from an outlet, a toner supply connection section 26 through which the toner passes from the outlet toward the toner storage section 20, a vertical movement mechanism 28 that applies vibrations to at least a part of the toner supply connection section 26, a data analysis section 34 that estimates an estimated toner consumption amount as an estimated developer consumption amount required for the next print, and a device control section 230 that controls the vertical movement mechanism 28, and the device control section 230 is configured to operate the vertical movement mechanism 28 when the value of the estimated toner consumption amount becomes equal to or exceeds a toner consumption amount threshold 61 as a threshold value.

As a result, when it is expected that the amount of toner supplied from the toner cartridge 13 to the image forming unit 12 will be large, the image forming device 201 operates the up-down movement mechanism 28 in advance before the printing operation to vibrate the toner supply connection part 26, shaking off the toner adhering to the inner wall surface of the toner supply connection part 26 and creating a situation in which toner is less likely to clog, thereby reducing the number of times that an operation to clear a toner clog is required during a printing operation.

In addition, the image forming device 201 according to the third embodiment can achieve the same effects as the image forming device 1 according to the first embodiment.

[4. Fourth embodiment]
[4-1. Control configuration of image forming apparatus]
As shown in FIG. 14 in which the same reference numerals are used for components corresponding to those in FIG. 5, an image forming apparatus 301 according to the fourth embodiment differs from the image forming apparatus 1 according to the first embodiment in that it has a device control unit 330 instead of the device control unit 30, but is otherwise configured in the same manner.

The device control unit 330 according to the fourth embodiment has a storage unit 336 instead of the storage unit 36, and is different in that a clock unit 63 has been added, but is otherwise configured in the same way. The storage unit 336 according to the fourth embodiment stores an elapsed time threshold 65 and a toner supply execution time 66. The clock unit 63 is a real-time clock, and manages time information. The toner supply execution time 66 indicates the time when the most recent toner supply operation was performed for each image forming unit 12. The elapsed time threshold 65 is a preset threshold that is a condition for performing a toner clogging removal operation for each image forming unit 12. In other words, the image forming device 301 performs a toner clogging removal operation for an image forming unit 12 for which the elapsed time since the previous toner supply operation is equal to or greater than the elapsed time threshold 65.

[4-2. Toner clogging elimination process]
A specific procedure for the toner clogging removal process by image forming apparatus 301 will be described with reference to the flowchart in Fig. 15. When the printing operation is completed, device control section 330 reads out a toner clogging removal process program from storage section 336 and executes it to start toner clogging removal process procedure RT401, and proceeds to step SP401. In this embodiment, after the printing operation is completed, it is determined whether or not to perform a toner clogging removal operation, and the condition for this determination is the elapsed time since the most recent toner supply operation.

In step SP401, the device control unit 330 obtains the current time from the clock means 63 and proceeds to step SP402. In step SP402, the device control unit 330 reads the toner supply implementation time 66 from the storage means 336 and proceeds to step SP403. In step SP403, the device control unit 230 reads the elapsed time threshold 65 from the storage means 336 and proceeds to step SP404. In step SP404, the device control unit 230 calculates the elapsed time Δt by subtracting the toner supply implementation time 66 from the current time and proceeds to step SP405.

In step SP405, the device control unit 330 compares the calculated elapsed time Δt with the elapsed time threshold 65 in the memory means 336, and determines whether there is an image forming unit 12 whose elapsed time Δt is equal to or greater than the elapsed time threshold 65. If a negative result is obtained here, this indicates that there is no image forming unit 12 whose elapsed time Δt is equal to or greater than the elapsed time threshold 65, and therefore there is no need to perform a toner clogging clearing operation, and in this case the device control unit 330 proceeds to step SP409, and ends the toner clogging clearing processing procedure RT401.

On the other hand, if a positive result is obtained in step SP405, this indicates that there is a target image forming unit 12 whose elapsed time Δt is equal to or greater than the elapsed time threshold value 65, and therefore a toner clogging clearing operation needs to be performed, and in this case the device control unit 330 proceeds to step SP406.

In step SP406, the device control unit 330 starts the operation of moving the image forming unit up and down of the target image forming unit by starting the driving of the lift-up motor 28m, and proceeds to step SP407 while continuing to drive the lift-up motor 28m. In step SP407, the device control unit 330 judges for each target image forming unit whether the image forming unit up and down movement operation has been performed a preset number of times. If a negative result is obtained here, this indicates that there is a target image forming unit that has not yet performed the image forming unit up and down movement operation the specified number of times. In this case, the device control unit 330 repeats step SP407, and when the image forming unit up and down movement operation is performed the specified number of times in each of the target image forming units, a positive result is obtained in step SP407, and the device control unit 330 proceeds to step SP408, and the toner clogging removal processing procedure RT401 is terminated. In the image forming device 301 according to this embodiment, the up and down movement mechanisms 28 of all image forming units 12 are independently movable, so the image forming unit up and down movement operations in all target image forming units are performed simultaneously.

[4-3. Toner supply process]
A specific procedure for the toner supply process by the image forming apparatus 301 will be described with reference to the flowchart in Fig. 16. The device control unit 330 starts the toner supply process procedure RT501 by reading and executing a toner supply process program from the storage unit 336, and proceeds to step SP501. In step SP501, the device control unit 330 judges whether or not the toner sensor 25 has detected a toner low level before or during the printing operation. If a negative result is obtained here, this indicates that the toner is not low and the amount of toner in the toner storage unit 20 is equal to or greater than the lower limit, and in this case the device control unit 330 proceeds to step SP510, ends the toner supply process procedure RT501, and if a printing operation is in progress, proceeds to resume the printing operation.

On the other hand, if a positive result is obtained in step SP501, this indicates that the amount of toner in the toner storage unit 20 has fallen below the lower limit and a toner supply operation needs to be performed, and the device control unit 330 then proceeds to step SP502. In step SP502, if a printing operation is in progress, the device control unit 330 stops the new paper feed operation and waits for printing of the pages that have already been fed to finish, thereby interrupting the printing operation, and then proceeds to step SP503. The following describes the case where toner low is detected by the toner sensor 25 of image forming unit 12Y, but the same operation occurs when toner low is detected in image forming units 12 of other colors.

In step SP503, after printing of the pages that have been fed is completed, the device control unit 330 starts the toner supply operation and proceeds to step SP504. At this time, the device control unit 330 drives the toner supply motor 43 and rotates the toner transport spiral 15 to transport toner from the toner cartridge 13Y to the image forming unit 12Y in the toner supply duct 14, and supplies toner to the image forming unit 12Y.

After continuing the toner supply operation for a certain period of time, in step SP504, the device control unit 330 determines whether toner low has been detected again by the toner sensor 25. If a positive result is obtained here, this indicates that a situation requires action by the operator, such as a toner blockage inside the toner supply duct 14Y, and the device control unit 330 then proceeds to step SP509. In step SP509, the device control unit 330 generates a toner supply error, proceeds to step SP511, and stops the printing operation, waiting for the operator to respond to the malfunction, proceeds to step SP512, and ends the toner supply processing procedure RT501.

On the other hand, if a negative result is obtained in step SP504, this indicates that the toner is no longer low, and at this time the device control unit 330 proceeds to step SP505, terminates the toner supply operation, and proceeds to step SP506. In step SP506, the device control unit 330 obtains the current time from the clock means 63, proceeds to step SP507, updates and stores the current time as the toner supply execution time 66 in the storage means 336, proceeds to step SP508, terminates the toner supply processing procedure RT501, and starts a printing operation, or, if a printing operation is in progress, proceeds to resume the printing operation.

[4-4. Effects, etc.]
In the above configuration, the image forming device 301 is provided with a device control unit 330 as an elapsed time calculation means for calculating the elapsed time Δt from the previous toner supply operation from the toner cartridge 13 to the toner storage unit 20, and if it is detected before the start of or during a printing operation that the elapsed time Δt is equal to or greater than the elapsed time threshold value 65, an image forming unit up and down movement operation is executed after the printing operation.

Therefore, when a long time has passed since the last toner supply, toner has built up on the inner wall surface of the toner supply connection 26, and there is a possibility of toner clogging at the end of a printing operation, the image forming device 301 can preventatively clear the toner clogging. This eliminates the need for the image forming device 301 to perform a toner clogging clearing operation before starting the next printing operation. In this way, the image forming device 301 can avoid interrupting the printing operation due to a toner clogging, and can start the printing operation promptly after receiving print data.

In addition, the image forming device 301 according to the fourth embodiment can achieve the same effects as the image forming device 1 according to the first embodiment.

5. Other embodiments
In the above-described first embodiment, the toner supply connection part 26 is vibrated by controlling the vertical movement mechanism 28 to move the image forming unit 12 up and down between the raised position and the lowered position. The present invention is not limited to this, and a vibration imparting mechanism for vibrating the toner supply connection part 26 may be separately attached to the toner supply connection part 26, and the toner supply connection part 26 may be vibrated by the vibration imparting mechanism. The same applies to the second to fourth embodiments.

In the first embodiment described above, the toner cartridge 13 discharges toner from the discharge port and supplies the toner to the image forming unit 12 via the toner supply duct 14 and the toner supply connection portion 26. The present invention is not limited to this, and the toner supply duct 14 may be omitted, and the toner cartridge 13 may discharge toner from the discharge port and supply the toner directly to the image forming unit 12 via the toner supply connection portion 26. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, the central axes of the duct side connection portion 26a and the unit side connection portion 26b of the toner supply connection portion 26 are aligned in the vertical direction. The present invention is not limited to this, and the central axes of the duct side connection portion 26a and the unit side connection portion 26b of the toner supply connection portion 26 may be inclined with respect to the vertical direction. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, the duct side connection portion 26a and the unit side connection portion 26b of the toner supply connection portion 26 are configured from hard resin molded parts. The present invention is not limited to this, and the toner supply connection portion 26 may be configured to have a bellows shape that is expandable and contractable in the vertical direction. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, a case has been described in which the unit side connection part 26b is moved in the vertical direction relative to the fixed duct side connection part 26a. The present invention is not limited to this, and the duct side connection part 26a may be moved in the vertical direction relative to the unit side connection part 26b, or both the duct side connection part 26a and the unit side connection part 26b may be moved in the vertical direction. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, a vertical movement mechanism 28 that drives independently of each other is provided for each image forming unit 12, and a lift-up motor 28m is provided for each image forming unit 12. The present invention is not limited to this, and each image forming unit 12 may be raised and lowered individually by a single lift-up motor by combining a transmission mechanism including a clutch. Also, the vertical movement mechanism 28 may be configured to raise and lower multiple image forming units 12 collectively. The same applies to the second to fourth embodiments.

Furthermore, in the second embodiment described above, a case was described in which the image forming unit up-down movement operation is performed a specified number of times after weighting a number of times greater than a specified number for a target image forming unit whose humidity information is equal to or greater than the humidity threshold. The present invention is not limited to this, and the point is that it is sufficient to execute the image forming unit up-down movement operation for a longer period of time than the time required to execute the image forming unit up-down movement operation a specified number of times for a target image forming unit whose humidity information is equal to or greater than the humidity threshold.

Furthermore, in the second embodiment described above, a case was described in which the image forming unit is moved up and down a specified number of times after weighting for a target image forming unit whose humidity information is equal to or greater than a humidity threshold. The present invention is not limited to this, and the image forming unit may be moved up and down a specified number of times after weighting for a target image forming unit whose temperature information is equal to or greater than a predetermined temperature threshold, or the humidity information and temperature information may be combined to move the image forming unit up and down a specified number of times after weighting.

Furthermore, in the third embodiment described above, a case has been described in which a wireless RFID chip 52 is used. The present invention is not limited to this, and a wired tag chip may also be used.

In the first embodiment described above, the present invention has been described as being applied to an image forming apparatus 1 of a so-called direct transfer type, in which a toner image is directly transferred from the photosensitive drum 21 to the medium P. The present invention is not limited to this, and the present invention may also be applied to an image forming apparatus of a so-called intermediate transfer type (or secondary transfer type), in which a toner image of each color is transferred from the photosensitive drum 21 to an intermediate transfer belt so as to be superimposed in sequence, and the toner image is then transferred from this intermediate transfer belt to the medium P. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, the present invention is applied to an image forming apparatus 1 that uses a developer for a one-component development method. The present invention is not limited to this, and the present invention may be applied to an image forming apparatus that uses a developer for a two-component development method, in which a carrier and a toner are mixed together and friction between the carrier and the toner is used to impart an appropriate amount of charge to the toner. The same applies to the second to fourth embodiments.

Furthermore, in the first embodiment described above, the present invention has been described as being applied to an image forming apparatus 1 that has four image forming units 12 and forms a color image using toner of four colors. The present invention is not limited to this, and the present invention may be applied to an image forming apparatus that has three or less image forming units 12 or five or more image forming units 12 and forms an image using toner of a predetermined number of colors. The same applies to the second to fourth embodiments.

Furthermore, in the above-mentioned first embodiment, the present invention has been described as being applied to an image forming device 1 that is a single-function printer. The present invention is not limited to this, and may be applied to image forming devices having various other functions, such as an MFP (Multi Function Peripheral) that has the functions of a copier or facsimile machine. The present invention may also be applied to various electronic devices that form images on a medium P such as paper using a developer by electrophotography. The same applies to the second to fourth embodiments.

Furthermore, the present invention is not limited to the above-mentioned embodiment or other embodiments. In other words, the scope of application of the present invention extends to embodiments that arbitrarily combine the above-mentioned embodiment with part or all of the other above-mentioned embodiments, or to embodiments that extract parts of the above-mentioned embodiment.

Furthermore, in the above-mentioned third embodiment, the image forming device 201 is configured as an image forming device by the image forming unit 12 as an image forming unit, the toner cartridge 13 as a developer storage unit, the toner supply connection unit 26 as a developer supply connection unit, the up-down movement mechanism 28 as a vibration imparting mechanism, the data analysis unit 34 as developer consumption estimation means, and the device control unit 230 as a control unit. The present invention is not limited to this, and the image forming device may be configured by an image forming unit, developer storage unit, developer supply connection unit, vibration imparting mechanism, developer consumption estimation means, and control unit having various other configurations.

The present invention can be used when printing images on media using an electrophotographic image forming device.

1, 101, 201, 301: image forming apparatus, P: medium, 2: medium storage tray, 3: medium transport path, 4: pickup roller, 5a, 5b, 5c, 5d, 5e: transport roller pair, 6: transfer section, 7: transfer belt, 8: belt support roller, 9: belt drive roller, 10: transfer roller, 12: image forming unit, 13: toner cartridge, 14: toner supply duct, 15: toner transport spiral, 17: fuser unit, 18: medium accumulation tray, 19: developing roller, 20: toner storage section, 21: photosensitive drum, 22: LED head, 23: cleaning blade, 24: support shaft, 25: toner sensor, 26: toner supply connection section, 26a: duct side connection section, 26b: unit side connection section, 28: up and down movement mechanism, 28a: elliptical cam, 28m: lift-up motor, 30 , 130, 230, 330...device control unit, 31...motor driving means, 32...image forming unit vertical position detection means, 33...printing information receiving unit, 34...data analysis unit, 36, 136, 236, 336...storage means, 37...estimated toner supply amount counter, 40...toner remaining amount detection means, 42...motor control unit, 43...toner supply motor, 44...image forming unit vertical position detection unit, 45...toner remaining amount detection unit, 47...temperature and humidity sensor, 48...temperature and humidity detection means, 49...clogging removal determination table, 52...RFID chip, 53...attachment/detachment sensor, 54...toner installation detection unit, 55...RFID communication unit, 56...RFID reading means, 57...toner cartridge installation detection means, 59...new product replacement detection flag, 61...toner consumption threshold, 63...timing means, 65...elapsed time threshold, 66...toner supply implementation time.

Claims (8)

an image forming unit having a developer storage section for storing a developer;
a developer storage section for storing the developer and discharging the developer from a discharge port;
a developer supply connection portion through which the developer passes from the discharge port toward the developer accommodating portion; and a vibration imparting mechanism that imparts vibration to at least a portion of the developer supply connection portion.
a developer consumption estimating means for estimating an estimated developer consumption required for the next printing;
A control unit that controls the vibration imparting mechanism,
The control unit is
the vibration applying mechanism is actuated when the value of the estimated developer consumption amount becomes equal to or greater than a threshold value. the developer storage unit is a developer cartridge that is detachably attached to the image forming apparatus,
The developer cartridge may further include a developer cartridge installation detection unit for detecting installation of the developer cartridge.
The control unit is
2. The image forming apparatus according to claim 1, wherein the vibration applying mechanism is operated before printing after the developer cartridge installation detection means detects that the developer cartridge is installed. the developer supply unit further includes an elapsed time calculation unit that stores an elapsed time from a previous supply of developer from the developer storage unit to the developer accommodating unit,
The control unit is
3. The image forming apparatus according to claim 1, wherein the vibration mechanism is activated after printing when the elapsed time is detected to be equal to or greater than a threshold value. The vibration imparting mechanism includes:
a moving mechanism for moving the image forming unit from an image forming position to a non-image forming position,
4. The image forming apparatus according to claim 1, wherein the control section applies vibration to the developer supply connection section by actuating the movement mechanism. The moving mechanism includes:
5. The image forming apparatus according to claim 4, further comprising a mechanism for moving the image forming unit up and down to move the transfer member and the image carrier into and out of contact with each other. The device further includes an environmental information detection unit that detects at least one of temperature and humidity,
6. The image forming apparatus according to claim 1, further comprising: a first time for operating the vibration imparting mechanism at a predetermined first value for at least one of the temperature and the humidity; and a second time, which is equal to or longer than the first time, for operating the vibration imparting mechanism at a second value greater than the first value. The developer supply connection portion is
a first member through which the developer passes; and a second member having an inner shape larger than an outer shape of the first member,
The second member is inserted into the first member,
7. The image forming apparatus according to claim 1, wherein at least one of the first member and the second member moves in conjunction with the vibration imparting mechanism to impart vibration to the developer supply connection portion. The developer supply connection portion is
8. The image forming apparatus according to claim 1, wherein the developer passes from the top to the bottom.

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