JP2024050197A - Image forming device - Google Patents

Abstract

An object of the present invention is to reduce erroneous ordering of process cartridges in a configuration in which process cartridges are automatically ordered.
[Solution] The device is equipped with a CPU 213 that controls the display unit so that there is a first period (A-2) in which the amount of remaining toner acquired by detection unit A is displayed on the display unit before detection unit B acquires an amount of remaining toner corresponding to a threshold value, and a second period (B-1) in which the amount of remaining toner acquired by detection unit B is displayed on the display unit after detection unit B acquires an amount of remaining toner corresponding to the threshold value, and the CPU 213 predicts the timing (point F) when the toner will run out based on the amount of remaining toner acquired by detection unit B in the second period (B-1) (consumption prediction B) and orders a development unit based on the predicted timing (point G).
[Selected Figure] Figure 6

Description

The present invention relates to an image forming apparatus, for example, an electrophotographic apparatus such as a copying machine, a printer, or a facsimile machine, and a process cartridge that can be attached to or detached from the electrophotographic apparatus.

Conventional image forming devices widely use a process cartridge system for the purpose of simplifying the replacement and maintenance of consumables such as photoconductors and toner. In the process cartridge system, a toner storage section, developing means, photoconductor, charging means, cleaning means including a waste toner container, etc. are integrated into a cartridge. Since the process cartridge is detachable from the main body of the image forming device, users can perform maintenance of the image forming device themselves without relying on a service technician.

Image forming devices that use a process cartridge system are provided with a toner remaining amount acquisition means for notifying a user when the amount of toner remaining in the process cartridge becomes low. In addition, a system has been constructed that uses the toner remaining amount acquisition means to predict the timing when toner will run out from the change in the amount of toner remaining, and automatically orders a process cartridge in advance. This allows the process cartridge to be replaced immediately even if the toner runs out. Regarding toner consumption, for example, Patent Document 1 discloses a method of acquiring toner consumption using a pixel count method. Also, for example, Patent Document 2 discloses a method of detecting toner remaining amount using a plate antenna method. Furthermore, Patent Document 3 discloses a method of acquiring toner consumption using a combination of the pixel count method and the plate antenna method.

JP 2004-157501 A JP 2001-134064 A JP 2018-005039 A

However, in the case of the pixel count method, which calculates the remaining toner amount from the number of pixels (pixel count) that make up an image, there may be an error between the calculated remaining toner amount and the actual remaining toner amount. In addition, when calculating the remaining toner amount using the plate antenna method, the range in which the remaining toner amount can be detected accurately is narrow, and if the range is widened, the detection accuracy of the remaining toner amount may decrease. Furthermore, when the pixel count method and the plate antenna method are used together, there are the following problems. When the difference between the detection result by the pixel count method and the detection result by the plate antenna method is large, depending on the processing method of both detection results, there is a risk that the remaining toner amount may change as if it has changed suddenly. The image forming device may mistakenly determine that a sudden change in the remaining toner amount is the result of the user using too much toner, and may automatically order a replacement process cartridge even though there is sufficient toner remaining. Conversely, there may be cases in which the remaining toner amount does not change and appears to be stagnant. To prevent this from happening, it is possible to change the change range of the remaining toner amount. In this case, there is a risk that the toner will run out before the toner end is notified, or that the toner end will be notified even though there is still toner remaining. This may make it impossible to detect the correct timing of the toner end and automatically order a process cartridge. For this reason, there is a need to reduce erroneous ordering of process cartridges in configurations where process cartridges are ordered automatically.

The present invention was made under these circumstances, and aims to reduce erroneous ordering of process cartridges in a configuration in which process cartridges are automatically ordered.

In order to solve the above-mentioned problems, the present invention has the following configuration.
(1) An image forming apparatus comprising: a developing unit having a toner storage section that stores toner and a developing roller that carries the toner in the toner storage section; and a photosensitive drum to which toner is supplied from the developing roller, and which performs image formation on a recording material based on image data, the image forming apparatus comprising: a first acquisition section that acquires an amount of toner consumed by the image formation based on the image data and acquires an amount of toner remaining in the toner storage section based on the amount of toner consumed; a second acquisition section that acquires the amount of toner remaining based on a correlation value that correlates with the amount of toner stored in the toner storage section; a display section that displays the amount of toner remaining acquired by the first acquisition section or the amount of toner remaining acquired by the second acquisition section; an image forming apparatus comprising: a control unit that controls the display unit so that there is a first period in which the remaining toner amount acquired by the first acquisition unit is displayed on the display unit before the remaining toner amount corresponding to a threshold value is acquired by the second acquisition unit, and there is a second period in which the remaining toner amount acquired by the second acquisition unit is displayed on the display unit after the remaining toner amount corresponding to the threshold value is acquired by the second acquisition unit; a prediction means that predicts the timing when the toner will run out based on the remaining toner amount acquired by the second acquisition unit during the second period; and an ordering means that orders the developing unit based on the timing predicted by the prediction means.

According to the present invention, in a configuration in which process cartridges are automatically ordered, it is possible to reduce erroneous ordering of process cartridges.

Schematic diagram of an image forming apparatus according to embodiments 1 to 3 Schematic diagram showing a developing unit inside a process cartridge according to embodiments 1 to 3. FIG. 1 shows a toner remaining amount detection circuit according to the first to third embodiments. FIG. 1 is a block diagram showing a detection unit A, a detection unit B, and a toner remaining amount detection device according to first to third embodiments; Graph showing the change in remaining toner amount in detection unit A and predicted consumption A in embodiment 1 Graph showing the toner remaining amount transition and consumption prediction B of detection unit A in Example 1 Graph showing the change in remaining toner amount in detection unit A of Example 2 Graphs showing consumption forecast C, consumption forecast D, and consumption forecast E of Example 2 Graph showing the change in remaining toner amount in Example 3

The image forming apparatus of the embodiment is, for example, an apparatus that forms an image on a recording medium using an electrophotographic image forming process. For example, image forming apparatuses include electrophotographic copying machines, electrophotographic printers (e.g., LED printers, laser beam printers, etc.), electrophotographic facsimile machines, word processors, and combination machines (multifunction printers) of these. In addition, a process cartridge refers to one that is detachably attached to the main body of an image forming apparatus. Below, an embodiment will be described with reference to the drawings.

[Image forming apparatus]
The overall configuration of an electrophotographic image forming apparatus (image forming apparatus) will be described. FIG. 1 is a schematic diagram of an image forming apparatus 200 with a process cartridge 222 attached. The image forming apparatus 200 includes a photosensitive drum 201, which is an image carrier, and a laser scanner 204, which is an exposure means for scanning a laser beam on the photosensitive drum 201 (on the photosensitive drum) by a semiconductor laser 203. The image forming apparatus 200 includes a replaceable process cartridge 222. The process cartridge 222 includes a charging roller 202, which is a charging means for uniformly charging the photosensitive drum 201, and a developing roller 224, which is a developer carrier for developing an electrostatic latent image formed on the photosensitive drum 201 with the toner 231 carried thereon. The developing roller 224 supplies toner to the photosensitive drum 201. The process cartridge 222 includes a developing blade 305 for regulating the amount of toner on the developing roller 224, a developing device 207 (developing unit), which is also a toner storage section for storing the toner 231, and a non-volatile memory 230 for storing information.

The image forming apparatus 200 includes a transfer roller 208 for transferring the toner image developed on the photosensitive drum 201 to a predetermined recording material 216, and a fixing device 219 for fusing the unfixed toner transferred to the recording material 216 with heat. The fixing device 219 includes a temperature thermistor 225 used to control the temperature of the fixing device 219. The image forming apparatus 200 includes a paper feed roller 210 for feeding the recording material 216, a top sensor 214 for synchronizing with the conveyance of the recording material 216, and a discharge roller 211 for discharging the recording material 216 after fixing to a discharge tray 217. The image forming apparatus 200 includes a discharge sensor 215 for detecting the presence or absence of the recording material 216 after fixing.

The image forming apparatus 200 is equipped with an engine controller 212, which has a CPU 213 as a control unit, and which functions as a toner remaining amount detection device 240 described later. The CPU 213 also functions as a prediction means for predicting the timing when toner will run out. The CPU 213 also functions as an ordering means for ordering a process cartridge 222 (developing unit) based on the predicted timing when toner will run out. The toner remaining amount detection device 240 has a pixel count measurement unit 241 and a toner remaining amount calculation unit 242 described later. The engine controller 212 controls each of the components described above.

Here, we will explain the ordering system in which the CPU 213 orders the process cartridges 222. The ordering system includes the CPU 213, which is the ordering side, and an order-receiving server, which is the order-receiving side. The CPU 213 and the order-receiving server are connected by a known wired or wireless network. The order-receiving server is, for example, a server of the manufacturer that released the process cartridge 222, an agency, a service center, etc. When the toner runs out, the CPU 213 sends information such as the product number and quantity of the process cartridges 222 to the order-receiving server via the network.

The image forming apparatus 200 is provided with a display unit 250 that displays the status of the remaining toner amount and the like. The display unit 250 displays various information of the image forming apparatus 200 and notifies the user. The display unit 250 may also function as an operation unit for performing various settings on the image forming apparatus 200. The display unit 250 displays the progress of the remaining toner amount by the CPU 213 and notifies the user. The display unit 250 is, for example, a liquid crystal monitor. When the display unit 250 also functions as an operation unit, it may have, for example, various input keys. The display unit 250 may be a touch panel, an operation panel, or the like. When the display unit 250 notifies the predicted result of the remaining toner amount, for example, the remaining toner amount may be displayed as digital data in 1% increments from 100% to 0%. When the display unit 250 notifies the remaining toner amount, for example, a high-resolution indicator display may be used.

[Pixel count method]
In the pixel count method, the amount of toner consumed in one image is obtained by multiplying the number of image pixels exposed by the laser (hereinafter referred to as the number of pixels) by the amount of toner consumed per pixel (hereinafter referred to as the unit toner consumption amount).The remaining amount of toner is then obtained by subtracting the amount of toner consumed from the amount of toner filled in the process cartridge.

The toner remaining amount detection method (pixel count method) of the first embodiment will be described in detail. The CPU 213 of the image forming apparatus 200 has a toner remaining amount detection device 240 that detects the remaining amount of toner 231 contained in the developer 207 (in the toner container) of the process cartridge 222. The toner remaining amount detection device 240 has a pixel count measurement unit 241 that measures the number of pixels of an image formed on the recording material 216 by the image forming operation. The number of pixels measured by the pixel count measurement unit 241 will be referred to as the pixel count value hereinafter. The toner remaining amount detection device 240 also has a toner remaining amount calculation unit 242 that calculates the remaining amount of toner 231 in the developer 207 from the measured pixel count value.

The pixel count measurement unit 241 counts the total number of pixels that the semiconductor laser 203 arranged in the laser scanner 204 irradiates onto the photosensitive drum 201 based on image data during image formation operation. The image forming device 200 of the first embodiment has a resolution of, for example, 600 dpi, and the length of one pixel in the main scanning direction (hereinafter also referred to as the main scanning direction width) is 42 μm. Here, the main scanning direction is the direction in which the semiconductor laser 203 scans the photosensitive drum 201, and is also the direction of the rotation axis of the photosensitive drum 201. The pixel count measurement unit 241 performs sampling of one pixel at a sampling period of, for example, 80 MHz.

In the first embodiment, VCn is the pixel count value of the laser irradiated onto the photosensitive drum 201 when an image is formed on one sheet of recording material 216. The printing rate A when one sheet of recording material 216 is printed will be described below. The printing rate when printing on A4 paper (210 mm wide, 297 mm long) at a resolution of 600 dpi is calculated by the following formula (1).
Printing rate A [%] = "Printed pixel count value VCn" ÷
"Pixel count value VCn printed on A4 paper at 100% print rate" Equation (1)

The amount of toner actually consumed varies depending on the lifespan of the photosensitive drum 201 and the developing unit 207, the printing rate A, etc. For this reason, the remaining toner amount calculation unit 242 sets a correction coefficient γ for unit toner consumption amount, and calculates a corrected pixel count value VCnt, which is a pixel count value corrected by the correction coefficient γ, using the following formula (2).
VCnt=VCn×γ Equation (2)

The remaining toner amount calculation unit 242 reads out the cumulative pixel count value VCr, which is the pixel count value accumulated since the start of use of the process cartridge 222, stored in the non-volatile memory 230 provided in the process cartridge 222. The remaining toner amount calculation unit 242 adds the corrected pixel count value VCnt calculated by equation (2) to the read cumulative pixel count value VCr, and calculates a total pixel count value VCt, which is the updated cumulative pixel count value (equation (3)).
VCt=VCr+VCnt Equation (3)

Next, the remaining toner amount calculation unit 242 reads out the pixel count threshold value VCth stored in the non-volatile memory 230. The remaining toner amount calculation unit 242 calculates the remaining amount of toner TP in the developing unit 207 from the pixel count threshold value VCth and the total pixel count value VCt calculated by the formula (3) using the following formula (4).
TP [%] = (1 - VCt / VCth) x 100 Formula (4)

Then, the remaining toner calculation unit 242 writes the total pixel count value VCt calculated by equation (3) to the non-volatile memory 230 as the updated cumulative pixel count value VCr.

Here, when detecting remaining toner using the pixel count method, the above-mentioned correction coefficient γ changes depending on the printed image, so there may be an error between the actual amount of toner consumed and the amount of toner consumption calculated using the pixel count method.

[Plate antenna system]
The plate antenna method utilizes the fact that the electrostatic capacitance between the metal plate 1 and the developing roller 224 and between the metal plate 1 and the metal plate 2 changes according to the amount of toner by providing a metal plate as an electrode at a position facing the developing roller 224 or at a plurality of other positions. That is, if the space between the metal plate 1 and the developing roller 224 or between the metal plate 1 and the metal plate 2 is filled with toner 231, the electrostatic capacitance therebetween becomes large. On the other hand, as the toner 231 decreases, the proportion of the space between the two that is occupied by air increases, and the electrostatic capacitance decreases. Therefore, if the relationship between the electrostatic capacitance between the metal plate 1 and the developing roller 224 or between the metal plate 1 and the metal plate 2 and the amount of toner is obtained in advance, the amount of remaining toner can be detected by measuring the electrostatic capacitance.

The toner remaining amount detection method (plate antenna method) by electrostatic capacitance of the first embodiment will be described. FIG. 2 shows a detailed diagram of the toner remaining amount detection by the plate antenna method. The plate antenna 302 is installed in the developer 207 so that the degree of reduction of the toner 231 can be directly detected by utilizing the characteristic that the toner 231 in the developer 207 moves fluidly due to the rotation of the stirring member 303. The material of the plate antenna 302 may be any plate-shaped material that is a good conductor, but when it is installed in the process cartridge 222, it is desirable to use a material that does not affect the toner particles and is resistant to environmental conditions such as humidity. And, the plate antenna 302 has a part on at least one side that can be electrically connected from the outside. This electrically connectable part may be directly connected by a conductor or pierced by a conductive pin.

In addition, in the toner remaining amount detection method using the developing roller 224 and the plate antenna 302, the amount of remaining toner is measured using the developing voltage applied to the developing roller 224. An AC voltage is used as the developing voltage applied to the developing roller 224, and the voltage value induced in the plate antenna 302 is detected. If the dielectric constant differs depending on the amount of remaining toner between the developing roller 224 and the plate antenna 302, the voltage value induced in the plate antenna 302 also differs. This voltage value (output value) is a correlation value that correlates with the amount of toner in the developer 207, and the amount of remaining toner is detected (obtained) according to this correlation value. The image forming apparatus 200 main body and the process cartridge 222 are provided with electrical contacts (not shown). When the process cartridge 222 is installed in the image forming apparatus 200 main body, the plate antenna 302 of the process cartridge 222 is connected to the toner remaining amount detection circuit 402 (see FIG. 3) in the image forming apparatus 200 main body through the electrical contacts.

Figure 3 shows a detailed circuit diagram of the toner remaining amount detection device 240 of the first embodiment. A development voltage circuit 401 for applying a development voltage is connected to a reference capacitor CL1, which serves as a reference capacitance. The reference capacitor CL1 is connected to a toner remaining amount detection circuit 402, through which a current I2 flows. The current I2 is divided into currents I3 and I4 by resistor R12. The reference voltage V4 is determined by the divided current I4 and resistor R11.

The developing voltage circuit 401 is also connected to the developing roller 224, and is connected to the toner remaining amount detection circuit 402 via the plate antenna 302. If the capacitance between the developing roller 224 and the plate antenna 302 is Ccrg, the current flowing from the plate antenna 302 to the toner remaining amount detection circuit 402 is I1. In FIG. 3, the capacitance between the developing roller 224 and the plate antenna 302 is diagrammatically illustrated using a capacitor symbol.

The current I1 is determined by the frequency f [Hz] and amplitude voltage Vpp [V] of the developing voltage, which is an AC voltage generated by the developing voltage circuit 401, and the above-mentioned capacitance Ccrg [pF]. The current I1 is connected to the inverting input terminal of the operational amplifier OP in the toner remaining amount detection circuit 402, and a voltage corresponding to the remaining amount of toner (hereinafter referred to as the toner remaining amount value) is output from the output terminal. Here, the toner remaining amount value is the output Vout of the operational amplifier OP, and is calculated by the following formula (5). A reference voltage V4 is input to the non-inverting input terminal of the operational amplifier OP. The output Vout is also referred to as the detection value. The resistance value of the resistor connected between the inverting input terminal and the output terminal of the operational amplifier OP is R10.
Vout [V] = V4 [V] - (f [Hz] x Vpp [V]
× Ccrg [pF] × R10 [Ω]) Equation (5)

The detection value Vout of the operational amplifier OP is output to the CPU 213 of the engine controller 212. The CPU 213 performs analog-to-digital (hereinafter, abbreviated as AD) conversion on the input detection value Vout to obtain a remaining toner amount value as a digital value. Here, the remaining toner amount value is calculated by the following formula (6).
Toner remaining amount value (A/D conversion value)=Vout [V]÷Voltage V12 [V] Equation (6)
The CPU 213 calculates the remaining toner amount using a conversion formula or a table. The calculated remaining toner amount value is written to the non-volatile memory 230. Hereinafter, the remaining toner amount is referred to as TP.

Here, in both the pixel count toner remaining amount detection method and the capacitance toner remaining amount detection method, when the toner remaining amount TP is 100%, this indicates that the toner 231 in the developer 207 is full and the process cartridge 222 is new. On the other hand, when the toner remaining amount TP is 0%, this indicates that the toner 231 in the developer 207 is almost depleted and it is time to replace the process cartridge 222.

[Method of Calculating Remaining Amount of Toner to be Notified]
FIG. 4 is a block diagram for explaining the toner remaining amount calculation method of the first embodiment. The photosensitive drum 201 and the semiconductor laser 203 constitute a detection unit A, which is a first acquisition unit. The detection unit A is used to detect the toner remaining amount using the pixel count method described above. The plate antenna 302, the development voltage circuit 401, and the toner remaining amount detection circuit 402 constitute a detection unit B, which is a second acquisition unit. The detection unit B is used to detect the toner remaining amount using the plate antenna method described above. The image forming apparatus 200 includes a video controller 251. The video controller 251 is connected to an external host device 252, such as a personal computer, in a known manner so as to be able to communicate with the host device 252, and the image forming apparatus 200 can also form an image according to a print instruction from the host device 252.

When the amount of toner in the developer 207 of the process cartridge 222 is 100% (initial use), the CPU 213 can detect the amount of toner using the pixel count method (detection unit A). On the other hand, when detecting the amount of toner using capacitance (detection unit B), the CPU 213 can detect the amount of toner using the plate antenna method in the range of 30% to 0% when the initial toner amount is 100%. In other words, the CPU 213 changes the remaining toner amount detection method to be used (detection unit A or detection unit B) depending on the amount of toner in the developer 207.

Here, in the detection unit A, an error may occur between the amount of toner actually consumed and the amount of toner consumed calculated using the detection unit A due to the influence of differences in the state of the photosensitive drum 201 and the toner 231. On the other hand, in the detection unit B, a parameter that correlates with the actual amount of toner in the developer 207 is detected, and therefore the detection accuracy is higher than that of the detection unit A. Therefore, when the CPU 213 displays the remaining toner amount on the display unit 250, the CPU 213 switches between the result detected using the detection unit A and the result detected using the detection unit B according to the remaining toner amount. For example, the CPU 213 may be configured to display the detection value of the remaining toner amount by the pixel count method using the detection unit A in the range of the remaining toner amount from 100% to 30% until the detection of the toner amount becomes possible using the detection unit B. Then, the CPU 213 may be configured to display the detection value of the remaining toner amount by the electrostatic capacitance using the detection unit B in the range of the remaining toner amount from 30% to 0%. In the first embodiment, the CPU 213 switches the remaining toner amount displayed on the display unit 250 from the detection value using the detection unit A to the detection value using the detection unit B when either the detection unit A or the detection unit B detects the remaining toner amount to be, for example, 30% first. The remaining toner amount when switching from the detection unit A to the detection unit B (for example, 30%) is also referred to as a threshold value. Hereinafter, the remaining toner amount displayed on the display unit 250 is also referred to as a notified toner amount.

Here, the period during which the amount of remaining toner acquired by detection unit A before the amount of remaining toner corresponding to the threshold value is acquired by detection unit B is displayed on display unit 250 is defined as a first period (A-1 or A-2 in FIG. 5 described later). Also, the period during which the amount of remaining toner acquired by detection unit B after the amount of remaining toner corresponding to the threshold value is acquired by detection unit B is displayed on display unit 250 is defined as a second period (B01 in FIG. 5 described later). CPU 213 controls display unit 250 so that there is a first period and a second period.

Figure 5 shows the transition of the notified toner amount when switching from detection unit A to detection unit B in the case where the toner amount detection value by the pixel count method of detection unit A is detected as less than the amount of toner actually consumed. In Figure 5, the horizontal axis shows the number of printed sheets (the cumulative number of printed sheets since the beginning of use) and the vertical axis shows the notified toner amount [%]. The notified toner amount is set to 100% when the process cartridge 222 is in the early stages of use (in other words, when it is unused). Also shown on the right side are the range detected by detection unit A (detection unit A range) of 100% to 30%, and the range detected by detection unit B (detection unit B range) of 30% to 0%. Here, the notified toner amount of 30% at which detection unit A switches to detection unit B is the threshold value mentioned above, and will be referred to as threshold value Th1 below.

Here, if there is no error between the detected value of the toner amount by the pixel count method of the detection unit A and the toner amount actually consumed, and the toner amount can be accurately detected by the pixel count method, the progress of the toner amount notified by the detection unit A will be A-1, as shown by the solid line. Note that "no error" also includes the case where the error is small enough to be negligible. In this case, switching is performed from the threshold value Th1 (point D0) of 30% toner amount to the detection unit B, and detection is performed up to the notified toner amount of 0% (point F) in the progress shown by B-1, as shown by the solid line. Note that the notified toner amount of 0% corresponds to the number of printed sheets of 12,000. The CPU 213 displays the notified remaining toner amount on the display unit 250 in each of the ranges of the detection unit A and the range of the detection unit B. In the progress from A-1 to B-1, the notified toner amount decreases with the same slope before and after point D0, in other words, without a sudden change in the progress.

On the other hand, when the toner amount detected by the pixel count method of detection unit A is detected as less than the amount of toner actually consumed, the reported remaining toner amount is displayed as the transition A-2 shown by the dashed line. Note that the slope of the transition A-2 is gentler than the slope of the transition A-1. Then, when detection unit B detects a toner amount of 30% (point D0) before detection unit A does, the reported toner amount switches from the detection value of detection unit A to the detection value of detection unit B. At that time, the remaining toner amount displayed on display unit 250 will suddenly switch from a toner amount of 60% (point C) reported by detection unit A to a toner amount of 30% (point D0) reported by detection unit B.

In this way, a difference occurs between the toner amount detection value (60%) by detection unit A and the toner amount detection value (30%) by detection unit B. In order to eliminate the toner amount detection difference between detection unit A and detection unit B, when switching from detection unit A to detection unit B, CPU 213 makes the following transition. That is, CPU 213 makes the transition from point C of detection unit A to point D on the B-1 transition of detection unit B so that the toner amount decreases by 1% for every predetermined number of printed sheets, for example, every four printed sheets. In FIG. 5, the transition of AB-1 shown by the dashed line has a slope of "1% toner amount/four printed sheets". In the range from point C to point D, CPU 213 makes the display unit 250 display the reported remaining toner amount according to the transition of AB-1. Then, when the remaining toner amount is no longer different from the toner amount calculated by detection unit B, in other words, when it reaches point D on the B-1 progression, the CPU 213 will display the reported remaining toner amount until the toner amount reaches 0% (point F) on the progression shown in the B-1 graph.

In other words, the CPU 213 controls the display unit 250 so that there is a third period when the amount of remaining toner corresponding to the threshold value is not obtained by the detection unit A until the amount of remaining toner corresponding to the threshold value is obtained by the detection unit B. Here, the third period is a period during which the amount of remaining toner is displayed according to the toner remaining amount transition (AB-1) (first toner remaining amount transition) that transitions the amount of remaining toner so that the amount of remaining toner decreases at a predetermined gradient relative to the amount of usage of the development unit between the first and second periods. The predetermined gradient is, for example, a slope of "1% toner amount/4 printed sheets."

If the trend is from point C of detection unit A to point D of detection unit B at a rate of "1% toner amount/4 printed pages," it is determined that the user is using toner at a high rate of printing (high toner consumption), and the trend is predicted to be the predicted consumption A shown by the dotted line. In this case, the CPU 213 predicts that the toner will run out at point E (8,200 pages), and outputs a signal to the ordering system (not shown) to automatically order a new process cartridge. Note that the ordering system uses a known configuration, and a description of it will be omitted. However, even when a new process cartridge arrives at the user's place, the process cartridge 222 that is being used can actually be used for up to 12,000 pages (point F). This can cause users to feel that there is something wrong with the ordering system.

The consumption prediction is based on the number of printed pages when a specific change in remaining toner occurs (hereinafter, referred to as toner remaining change). For example, the change in remaining toner changes from A-2 to AB-1 around point C. In such a case, a new consumption prediction is made based on the change in AB-1 after the change in remaining toner. For example, in FIG. 5, the CPU 213 predicts consumption prediction A based on the change in AB-1. The CPU 213 calculates the number of printed pages at which the remaining toner amount becomes 0% in the change in AB-1, for example, 8,200 pages. Note that if a consumption prediction is made based on a small change in remaining toner amount, the effect of error will be large, so care must be taken. In the first embodiment, for example, the consumption prediction is made based on the number of printed pages when the amount of toner changes by 10%.

The timing for ordering process cartridges 222 in the automatic ordering system may be, for example, the following timing. For example, it may be set appropriately when it is determined that the remaining number of printable sheets is less than a predetermined number, or when the number of days until the remaining number of printable sheets reaches zero (hereinafter referred to as the predicted number of days) is predicted and it is determined that the predicted number of days is shorter than a predetermined number of days. The predicted number of days may be obtained by a known method, such as detecting the elapsed time based on a timestamp when the predetermined number of sheets are printed. For example, the CPU 213 may measure the elapsed time when the most recent 500 sheets were printed, and calculate the predicted number of days from the remaining number of printable sheets.

In this way, the CPU 213 predicts the number of sheets of recording material that can be printed before the toner runs out, and if the predicted number is less than a predetermined number, orders a process cartridge 222. The CPU 213 also predicts the number of days that printing can be performed before the toner runs out, and if the predicted number of days is shorter than the predetermined number of days, orders a process cartridge 222.

In the first embodiment, an automatic order is placed when the number of printable sheets before there is no toner (0% toner remaining) falls below 1,000 sheets. In the first embodiment, 12,000 sheets can be printed before the toner runs out, and an automatic order is placed when there are 1,000 sheets remaining, i.e., the cumulative number of prints reaches 11,000 sheets.

Example 1 provides an image forming device 200 that performs consumption prediction that does not erroneously predict consumption and does not automatically order earlier than actual, even if the remaining toner amount detected when switching from detection unit A to detection unit B changes suddenly. Example 1 is characterized in that, in an image forming device 200 that detects remaining toner amount using multiple remaining toner amount detection methods, consumption prediction is performed using the results of one remaining toner amount detection method. In other words, by eliminating the sudden change in the amount of toner consumption that occurs when switching detection units, it is possible to prevent erroneous consumption prediction.

[Transition of remaining toner amount in Example 1]
FIG. 6 is a graph similar to FIG. 6, showing the transition of the remaining toner amount in the first embodiment. The same reference numerals and the like are attached to the same components as in FIG. 5. When the notified toner amount by the detection unit A is transitioning in the graph of A-2, if the detection unit B detects a toner amount of 30% (threshold Th1), the display of the notified toner amount is switched from the detection value of the detection unit A to the detection value of the detection unit B. That is, the notified toner amount transitions from point C, where the notified toner amount by the detection unit A is 60%, to point D, where the notified toner amount by the detection unit B is 30%, at a slope (AB-1) of "toner amount 1%/number of printed sheets 4". When the consumption forecast A is predicted in the section from point C to point D, where the switching between two different detection units is performed (hereinafter referred to as the transition section), it is determined that the toner will run out at point E, 8200 sheets, due to the sudden change in the remaining toner amount, as described above.

In the first embodiment, detection is performed by detection unit B after point D is reached, and after the transition shown in B-1 is reached, the CPU 213 refers to the number of printed pages at the timing when the toner remaining amount reaches point H, for example, and predicts consumption prediction B. That is, the CPU 213 predicts the timing when the toner will run out based on the amount of toner remaining obtained by detection unit B in the second period. In this case, it is predicted that the toner will run out at point F, which is about 12,000 printed pages. Therefore, at the timing of point G (printed pages 11,000 pages), about 1,000 pages before, the CPU 213 automatically orders a process cartridge 222. That is, the CPU 213 orders a process cartridge 222 (developing unit) based on the predicted timing.

In this way, in the configuration of Example 1, in which the detection unit A is switched to the detection unit B, the CPU 213 does not predict the consumption prediction during the transition period (also the third period), but performs the consumption prediction based on the detection result of the detection unit B after the transition period. This allows a new process cartridge to be automatically ordered at the appropriate timing. In Example 1, the consumption prediction B is performed based on the detection result of the detection unit B, which can detect the remaining amount in the range of 30% to 0%, but this is not limited to this. For example, if the consumption prediction is performed from an earlier timing, the consumption prediction may be performed based only on the result of the detection unit A. However, when the automatic ordering decision is made, it is desirable to use the detection unit B, which has high detection accuracy. In addition, the detection unit A detects the remaining amount of toner using a pixel count method, and the detection unit B detects the remaining amount of toner using electrostatic capacitance, but as long as the same detection can be performed, it is not limited to Example 1. In other words, it is applicable to an image forming apparatus that uses a detection unit that can detect the remaining amount of toner in a wide range from 100% to 0% and a detection unit that can detect the remaining amount of toner more accurately in a narrower range than the detection unit.

Note that, although detection unit B detects the remaining toner amount by electrostatic capacitance, this is not limited to this. Detection unit B may be an optical sensor having a light-emitting member that emits light into developer 207 and a light-receiving member that receives the light emitted from the light-emitting member and passed through developer 207. The correlation value that correlates with the amount of toner in developer 207 is the intensity of the light received by the light-receiving member or the length of time the light is received.

As described above, according to the first embodiment, in a configuration in which process cartridges are automatically ordered, it is possible to reduce erroneous ordering of process cartridges.

In the first embodiment, a method for reducing erroneous ordering of process cartridges 222 was described when there is a difference between the toner amount detection value by the pixel count method of detection unit A and the toner amount detection value by the capacitance method of detection unit B. That is, a case where the toner amount display changes suddenly when the toner amount display is switched from detection unit A to detection unit B is described. In the second embodiment, a case where there is little change in the toner amount when the toner amount display is switched from detection unit A to detection unit B, i.e., the toner amount "stagnates" is described. Note that in the description of the second embodiment, parts that overlap with the first embodiment will be omitted.

Figure 7 shows the progress of the reported remaining toner amount when switching from detection unit A to detection unit B in the case where the detected value of the toner amount by the pixel count method of detection unit A is calculated to be more than the amount of toner actually consumed. Figure 7 is a graph similar to Figure 5. When the detected value of the toner amount by the pixel count method of detection unit A is more than the amount of toner actually consumed, the remaining toner amount is displayed as the progress of A-3 shown by the dashed line. Then, when detection unit A detects the remaining toner amount to be 30% (threshold Th1) before detection unit B does (point J), detection unit B does not detect the remaining toner amount of 30% (threshold Th1), and the remaining toner amount is 30% (threshold Th1) or more.

Because the toner remaining amount in detection unit B is greater than 30%, the same toner remaining amount (30%) continues to be displayed on display unit 250 from point J of detection unit A to point D0 of detection unit B until detection unit B detects a toner amount of 30% (threshold Th1). In other words, CPU 213 displays the toner remaining amount as "stagnant" (shown by dashed line AB-2). Then, when detection unit B detects a toner remaining amount of 30% (threshold Th1), detection unit B displays the toner remaining amount down to 0% (point F) with a progression of B-1 shown by solid line.

If the toner remaining amount display remains unchanged between point J of detection unit A and point D0 of detection unit B, the user may mistakenly determine that the image forming device 200 or the process cartridge 222 is malfunctioning. In addition, when the CPU 213 predicts consumption based on the progress of AB-2, the timing when the toner runs out (also known as toner out) may be suddenly delayed in the predicted consumption.

In the second embodiment, the image forming apparatus 200 detects the remaining toner amount using multiple detection units, and performs consumption prediction based on the result of one detection unit, as in the first embodiment. In the second embodiment, the remaining toner amount corresponding to the threshold is obtained by detection unit A before the remaining toner amount corresponding to the threshold is obtained by detection unit B. The third period in the second embodiment is a period during which the remaining toner amount does not change between the first and second periods. In the second embodiment, the CPU 213 predicts the timing when the toner will run out based on the remaining toner amount obtained by detection unit B in the second period. In other words, by eliminating the stagnation in the change in the amount of toner consumption that occurs when the detection units are switched, erroneous consumption predictions can be prevented.

[Transition of remaining toner amount in Example 2]
Fig. 8 is a graph similar to Fig. 7 showing the transition of remaining toner amount in the case where the remaining toner amount display stagnates without changing when switching from detection unit A to detection unit B in Example 2. When the notified toner amount by detection unit A transitions to A-3, and detection unit A detects a remaining toner amount of 30% (threshold value Th1) (point J), remaining amount detection switches from detection unit A to detection unit B. However, since detection unit B does not detect a remaining toner amount of 30%, the notified toner amount remains stagnant at 30% from point J, where detection unit A detects a remaining toner amount of 30%, to point D0, where detection unit B detects a remaining toner amount of 30%.

If consumption prediction is performed including the section AB-2, which is a graph showing the transition from point J to point D, the following will occur. In other words, two consumption predictions can be predicted: point L of consumption prediction C, which connects point K on the transition of A-3 to point J, and point M of consumption prediction D, which connects point K to point D0. As a result, the timing of toner out changes between the two consumption predictions.

In this embodiment, therefore, after point D0 is reached and the state in which the amount of remaining toner is detected by detection unit B, i.e., the transition shown in B-1, consumption prediction E is performed using point N. That is, consumption prediction E is performed by referencing the number of printed pages at a given change in the amount of remaining toner at point N. In this case, since it is expected that the toner will run out at point F, which is approximately 12,000 printed pages, an automatic order for a process cartridge 222 is placed at the appropriate timing of point G, approximately 1,000 pages before that.

In this manner, in a configuration in which detection unit A is switched to detection unit B, consumption prediction is performed using the results of one detection unit. This allows new process cartridges to be automatically ordered at the appropriate timing, as in Example 1. Note that in Example 2, consumption prediction E was performed using the detection results of detection unit B, which can detect the remaining toner amount in the range of 30% to 0%, but if consumption prediction is to be performed from an earlier timing, consumption prediction may be performed using only the results of detection unit A. However, when making a decision on automatic ordering, it is desirable to use detection unit B, which has high detection accuracy.

As described above, according to the second embodiment, in a configuration in which process cartridges are automatically ordered, it is possible to reduce erroneous ordering of process cartridges.

In the first embodiment, it was explained that even if a sudden change occurs when the detection unit used to display the remaining toner amount is switched from detection unit A to detection unit B, accurate consumption prediction is performed and automatic ordering of process cartridges is performed at a more appropriate timing. In this case, a sudden change in the amount of toner is displayed to the user in the section AB-1 in FIG. 6. This may cause the user to feel uneasy about not being automatically ordered. In the third embodiment, an image forming device in which the remaining toner amount is also appropriately displayed is explained. Note that in the explanation of the third embodiment, parts that overlap with the first and second embodiments are omitted.

[Transition of remaining toner amount in Example 3]
FIG. 9 is a graph showing the transition of the remaining toner amount for explaining the third embodiment, and is the same as FIG. 6 and the like. When the toner amount notified by the detection unit A transitions to A-2, at the timing when the detection unit B detects the remaining toner amount of 30% (threshold Th1), the CPU 213 calculates the ratio between the detection value by the detection unit A and the detection value by the detection unit B. That is, since the detection unit A detects the remaining toner amount to be 60%, the CPU 213 judges that 40% (=100%-60%) of the toner has been consumed. On the other hand, since the detection unit B judges that the remaining toner amount is 30%, the CPU 213 judges that 70% (=100%-30%) of the toner has been consumed. From these, it can be seen that the ratio α of the consumed toner amount detected by the detection unit A and the detection unit B (=the amount of toner used (detection unit B)/the amount of toner used (detection unit A)) is 1.75 (=70%/40%). Hereinafter, the ratio α of the consumed toner amount is referred to as the toner consumption ratio α. The toner consumption ratio α is the ratio between the toner consumption based on the remaining toner amount acquired by detection unit A when the remaining toner amount corresponding to the threshold value is acquired by detection unit B, and the toner consumption based on the remaining toner amount corresponding to the threshold value acquired by detection unit B.

The CPU 213 determines the toner amount to be notified based on the detection result in the detection unit A using the toner consumption ratio α. For example, the CPU 213 determines the toner amount to be notified by multiplying the slope of the A-2 transition by the toner consumption ratio α. That is, in the section from point C to point F, the CPU 213 changes the toner amount to be notified according to the toner remaining amount transition of A-2' (second toner remaining amount transition) obtained by multiplying the A-2 transition by the toner consumption ratio α. The CPU 213 controls the display unit 250 so that there is a fourth period (A-2') instead of the second period (B-1) and the third period (AB-1). The fourth period is a period in which the toner remaining amount is displayed according to the second toner remaining amount transition in which the toner remaining amount is changed so that the toner remaining amount decreases based on the A-2 transition and the toner consumption ratio α.

This can be said to correct the remaining toner amount detected by detection unit A using the toner consumption ratio α. This makes it possible to display the remaining toner amount to the user as a progression from point C to point F. This also makes it possible to eliminate user anxiety caused by sudden changes in the amount of toner.

The calculation of the toner consumption ratio α may be performed at any time as long as detection values are obtained simultaneously from multiple detection units. Because the toner consumption ratio α varies depending on the image pattern, it is desirable to calculate the toner consumption ratio α successively. As in the first embodiment, the consumption prediction is performed by detection unit B, which can detect the remaining amount in the range of 30% to 0%, and the process cartridge is automatically ordered.

As described above, in a configuration that switches from detection unit A to detection unit B, by predicting consumption based on the detection result from one detection unit rather than predicting consumption based on two different detection results, it is possible to automatically order a new process cartridge at the appropriate timing. In addition, by calculating the toner consumption ratio α based on the detection values from the two detection units and correcting the detection result from detection unit A with the toner consumption ratio α, it is possible to prevent the progression of the remaining toner amount displayed on the display unit 250 from suddenly changing.

The configuration of Example 3 can also be applied to Example 2. That is, the CPU 213 may determine the notified toner amount by multiplying a value equivalent to the toner consumption ratio α by the gradient of the A-3 trend. For example, the CPU 213 may cause the display unit 250 to display the section between points J and D0 and the section between points D0 and F in FIG. 7 so that the remaining toner amount decreases with a gradient connecting points J and F. Note that the consumption forecast E in FIG. 8 is used to determine the timing of ordering the process cartridge 222.

Note that detection unit A detects the remaining toner amount by pixel counting, and detection unit B detects the remaining toner amount by capacitance, but this is not limited to Example 3 as long as similar detection is possible.

As described above, according to the third embodiment, in a configuration in which process cartridges are automatically ordered, it is possible to reduce erroneous ordering of process cartridges.

201 Photosensitive drum (detection section A)
203 Semiconductor laser (detection section A)
207 developing device 213 CPU
222 Process cartridge 224 Developing roller 250 Display unit 302 Plate antenna (detection unit B)
401 Development voltage circuit (detection section B)
402 Toner remaining amount detection circuit (detection section B)

Claims (9)

a developing unit including a toner storage section that stores toner and a developing roller that carries the toner in the toner storage section;
a photosensitive drum to which toner is supplied from the developing roller;
An image forming apparatus for forming an image on a recording material based on image data, comprising:
a first acquisition unit that acquires an amount of toner consumed by the image formation based on the image data, and acquires an amount of toner remaining in the toner storage unit based on the amount of toner consumed;
a second acquisition unit that acquires the remaining toner amount based on a correlation value that correlates with the amount of toner contained in the toner container;
a display unit that displays the remaining toner amount acquired by the first acquisition unit or the remaining toner amount acquired by the second acquisition unit;
a control unit that controls the display unit so that there is a first period during which the remaining toner amount acquired by the first acquisition unit is displayed on the display unit before the remaining toner amount corresponding to a threshold value is acquired by the second acquisition unit, and there is a second period during which the remaining toner amount acquired by the second acquisition unit is displayed on the display unit after the remaining toner amount corresponding to the threshold value is acquired by the second acquisition unit;
Equipped with
a prediction unit for predicting a time when the toner will run out based on the remaining amount of toner acquired by the second acquisition unit during the second period;
an ordering means for ordering the developing unit based on the timing predicted by the prediction means;
An image forming apparatus comprising: The image forming device according to claim 1, characterized in that, when the first acquisition unit does not acquire the toner remaining amount corresponding to the threshold value before the second acquisition unit acquires the toner remaining amount corresponding to the threshold value, the control unit controls the display unit so that there is a third period between the first period and the second period in which the toner remaining amount transition is displayed according to the toner remaining amount transition, in which the toner remaining amount transition is changed so that the toner remaining amount decreases at a predetermined gradient with respect to the usage amount of the development unit. When the toner remaining amount transition is a first toner remaining amount transition,
The image forming apparatus of claim 2, wherein the control unit controls the display unit so that, instead of the second period and the third period, there is a fourth period in which the trend of the remaining toner amount is displayed according to a second toner remaining amount trend that changes the display of the remaining toner amount so that the remaining toner amount decreases based on the ratio between the toner consumption amount based on the remaining toner amount acquired by the first acquisition unit when the remaining toner amount corresponding to the threshold value is acquired by the second acquisition unit and the toner consumption amount based on the remaining toner amount corresponding to the threshold value acquired by the second acquisition unit, and a trend in the toner consumption amount based on the remaining toner amount acquired by the first acquisition unit during the first period. The image forming device according to claim 1, characterized in that the control unit controls the display unit so that, when the toner remaining amount corresponding to the threshold value is acquired by the first acquisition unit before the toner remaining amount corresponding to the threshold value is acquired by the second acquisition unit, there is a third period between the first period and the second period during which the display of the toner remaining amount does not change. the prediction unit predicts the number of sheets of recording material that can be printed before the toner runs out,
5. The image forming apparatus according to claim 1, wherein the ordering unit orders the developing unit when the number of sheets predicted by the prediction unit becomes smaller than a predetermined number. the prediction means predicts the number of days that printing can be performed until the toner runs out,
5. The image forming apparatus according to claim 1, wherein the ordering unit orders the development unit when the number of days predicted by the prediction unit becomes shorter than a predetermined number of days. an exposure unit for forming an electrostatic latent image on the photosensitive drum,
5. The image forming apparatus according to claim 1, wherein the first acquisition unit acquires the toner consumption amount based on the number of image pixels of an electrostatic latent image formed by the exposure means and a unit toner consumption amount consumed by the image pixel. The toner storage unit has an electrode therein,
5. The image forming apparatus according to claim 1, wherein the correlation value is an output value that is output in response to an electrostatic capacitance between the electrode and the developing roller. a light emitting member that emits light into the toner containing section, and a light receiving member that receives the light that is emitted from the light emitting member and passes through the toner containing section,
5. The image forming apparatus according to claim 1, wherein the correlation value is an intensity of the light received by the light receiving member or a length of time during which the light is received.

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