Image formation apparatus, control method of image formation apparatus, and program

Abstract

To display information regarding a remaining amount of a developer, in order to solve such a problem that a sensor that detects the remaining amount of the developer may not provide sufficient detection accuracy when the remaining amount of the developer is equal to or greater than a predetermined amount.SOLUTION: An image formation apparatus according to the present application is capable of replenishing a developer without replacing a container that holds the developer and comprises detection means which detects an amount of the developer in the image formation apparatus, calculation means which calculates a remaining amount of the developer on the basis of the number of pixels of a formed image, and display means which displays the remaining amount of the developer. The display means displays a value based on the remaining amount calculated by the calculation means when the remaining amount of the developer detected by the detection means is equal to or greater than a predetermined amount, and displays a value based on the remaining amount detected by the detection means when the remaining amount of the developer detected by the detection means is less than the predetermined amount.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, a control method for an image forming apparatus, and a program. [Background technology]

[0002] Conventionally, in electrophotographic image forming devices such as copiers, printers, and facsimiles, images are formed by transferring developer from a developer storage unit within the image forming device onto paper via a photosensitive drum and an ITB belt. The remaining amount of developer in the developer storage unit is detected, and when the remaining amount becomes low, a message is displayed on the operation panel, prompting the user to replenish the image forming device with developer from a pack or bottle containing the developer.

[0003] Known methods for detecting the amount of remaining developer in a developer container include transmitting light through the developer container, detecting the transmitted light with a light-receiving element, and determining the amount of remaining developer based on the amount of light blocked by the developer, and using an antenna electrode to detect the capacitance of the developer. With the former method using an optical sensor, when there is a certain amount of developer in the developer container, the light is always blocked by the developer, so the detection signal from the light-receiving element remains unchanged and changes in the amount of remaining developer cannot be detected. With the latter method using an antenna sensor, the capacitance becomes extremely small when the amount of remaining developer falls below a certain amount, so changes in the amount of remaining developer in the developer container cannot be detected accurately when the amount of remaining developer is low.

[0004] In Patent Document 1, in order to successively detect the remaining amount of developer in the developer storage unit from full to empty, an antenna sensor that detects the remaining amount of developer in the range of 100% to 50% by electrostatic capacitance is used. Furthermore, Patent Document 1 proposes a technology that uses two sensors, in which an optical sensor that detects the remaining amount of developer in the range of 50% or less by the amount of light transmitted is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-228698 Summary of the Invention [Problem to be solved by the invention]

[0006] Since it is necessary to accurately detect when there is no developer left in the image forming device, the device is configured to include only an optical sensor that has high detection accuracy when the remaining amount of developer is below a predetermined amount. In this case, it is difficult for the sensor to detect the remaining amount of developer when the user replenishes the developer and the remaining amount of developer increases. As a result, it is sometimes impossible to know the developer consumption status for a while after replenishment of developer. [Means for solving the problem]

[0007] The image forming apparatus described in this embodiment is an image forming apparatus that can replenish developer without replacing the container in which the developer is held, and has a detection means for detecting the remaining amount of developer held in the image forming apparatus, a calculation means for calculating the remaining amount of developer based on the number of pixels of the formed image, and a display means for displaying the remaining amount of developer, wherein the display means displays a value based on the remaining amount calculated by the calculation means when the remaining amount of developer detected by the detection means is equal to or greater than a predetermined amount, and displays a value based on the remaining amount detected by the detection means when the remaining amount of developer detected by the detection means is less than the predetermined amount. [Effects of the Invention]

[0008] The image forming apparatus described in the present application can display information about the remaining amount of developer even when the remaining amount of developer is equal to or greater than a predetermined value. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention; [Figure 2]FIG. 1 is a control block diagram illustrating an embodiment of the present invention. [Figure 3] A configuration diagram of an image forming unit in an image forming apparatus [Figure 4] Flowchart for explaining remaining toner amount determination process during printing [Figure 5] Flowchart for explaining the process when toner is replenished [Figure 6] Toner remaining amount display example DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the components described in the embodiments are merely examples and are not intended to limit the scope of the present invention.

[0011] FIG. 1 is a cross-sectional view of a monochrome image forming apparatus 100 (hereinafter referred to as image forming apparatus 100) illustrating an embodiment of the present invention, and FIG. 2(a) is a diagram illustrating an example of a hardware configuration illustrating an embodiment of the present invention. The basic configuration will be explained using FIGS. 1 and 2(a). Note that, although the present embodiment will be explained using a monochrome image forming apparatus as an example, the image forming apparatus in the present invention may also be a color image forming apparatus.

[0012] 2A includes a CPU 301, a RAM 302, a ROM 303, and a non-volatile memory 313. The CPU 301 is connected to a power supply control unit 304, and controls the supply of power required to operate the image forming apparatus 100.

[0013] An operation unit 305 (hereinafter referred to as the operation unit) including a touch panel is connected to the CPU 301, and a user can request a desired operation, such as executing a print job or operating the power supply, from the CPU 301 via the operation unit 305. The CPU 301 is also connected to a PC 307 via an external I / F 306, which is an interface with external devices. The CPU 301 receives an instruction to start a print operation from the operation unit 305 or the PC 307 and starts an operation related to printing.

[0014] Also connected to the CPU 301 are an optical sensor 309 for executing a toner remaining amount detection process, which will be described later, and various loads 311 for driving motors and fans of the image forming apparatus 100 . For example, when a user issues a command to start a print operation via a PC 307, the CPU 301 controls the driving of an image forming unit 308 and various loads 311 configured from connected motors, fans, and the like.

[0015] 1, the image forming unit 120, the intermediate transfer belt 130, the primary transfer unit 123, and the secondary transfer unit 140. The CPU 301 can control the high voltage and drive of these units, as well as the laser scanner 122.

[0016] The ROM 303 stores a program for executing processes related to image formation and a program for executing processes described in flowcharts that will be described later.

[0017] The non-volatile memory 313 is a storage medium that can retain data even after power supply to the CPU 301 is stopped. The non-volatile memory 313 stores data stored in the RAM 302 that is to be used continuously even after the power is turned off / on.

[0018] The image forming unit 308, optical sensor 309, and various loads 311 are each connected to a power supply control unit 304, and are supplied with the power necessary for their operation. Depending on the power supply system used, the CPU 301 can switch between supplying and cutting off the power by controlling the drive of a relay 312 connected to the CPU 301.

[0019] The basic image forming operation will be described with reference to FIGS. 1 and 2(a).

[0020] Assume that a user issues an instruction to execute a print job using PC 307 connected to external I / F 306. PC 307 notifies CPU 301 of image forming apparatus 100 of an instruction to start a print operation. CPU 301 starts the paper feed operation from paper feed cassette 150 or the like. By driving a transport motor that serves as a drive source for paper feed pickup roller 151, paper feed pickup roller 151 rotates, and paper sheets in paper feed cassette 150 are fed and conveyed one by one. At this time, paper feed pickup sensor 152 monitors whether the paper feed operation was performed normally.

[0021] Meanwhile, CPU 301 starts the image forming operation by image forming unit 120 so that the image forming operation is completed in time for the paper to arrive at secondary transfer unit 140. Image forming unit 120 is configured to be fixed inside the image forming apparatus, and toner can be replenished through replenishing port 125.

[0022] 3 is a diagram showing the configuration of the image forming unit 120. Reference numeral 124 denotes a photosensitive member, 32 denotes a charging roller, 33 denotes a developing device having a developing roller 43, and 34 denotes a photosensitive member cleaner.

[0023] The photosensitive member 124 and the charging roller 32 are driven by the same drive source. The developing roller 43 is driven separately from the photosensitive member 124, and the image forming apparatus 100 is configured so that it is possible to stop only the developing roller 43 separately from the photosensitive member 124. Reference numeral 126 denotes a toner stirring screw, which stirs the toner in the developing device 33 by the same drive source as the developing roller 43.

[0024] In the image forming apparatus 100 described in this embodiment, toner is replenished using a toner pack that holds toner, rather than replacing a toner cartridge, which is a container that holds toner. In this embodiment, a toner pack 128 containing toner is attached to a replenishing port 125, and toner is replenished from the toner pack 128 to the developing device 33. The developing device 33 holds toner as a toner tank and supplies the toner to the developing roller.

[0025] After the surface of the photoreceptor 124 is charged by the charging roller 32, a latent image is formed on the photoreceptor 124 by a laser emitted from the laser scanner 122 in FIG. 1. The formed latent image is then developed onto the photoreceptor 124 by toner in the developing device 33 via the developing roller 43. Thereafter, a primary transfer voltage is applied to the toner image developed on the photoreceptor 124 in the primary transfer unit 123 in FIG. 1, and the toner image is transferred to the intermediate transfer belt 130 in FIG. 1. The toner image transferred to the intermediate transfer belt 130 reaches the secondary transfer unit 140 as the intermediate transfer belt 130 rotates.

[0026] 2(a) is composed of a light-emitting element 309a and a light-receiving element 309b. The remaining toner amount is determined using the detection result of the optical sensor 309 and a predicted toner consumption value obtained by converting the integrated value of the pixel count, which counts the number of pixels for each printed image, into a toner consumption amount. A specific method for determining the remaining toner amount will be described later.

[0027] Returning to FIG. 1 again, the following explanation will be given.

[0028] A sheet of paper fed from a paper feed cassette 150 by a paper feeding operation is transported downstream of the image forming apparatus by transport path rollers 153, 154, and 155. CPU 301 detects the position of the transported sheet of paper by monitoring pre-register transport sensor 160. Then, taking into consideration the timing when the leading edge of the sheet reaches pre-register transport sensor 160, the transport of the sheet is controlled so that the leading edge of the sheet and the leading edge of the toner image on intermediate transfer belt 130 coincide with each other at secondary transfer unit 140. For example, if it is determined that the sheet has arrived earlier than the toner image, registration rollers 161 stop the sheet for a predetermined time, and then transport is resumed to align the leading edges.

[0029] In this manner, a secondary transfer voltage is applied to the paper and toner image that have reached secondary transfer unit 140, and the toner image is transferred onto the paper.

[0030] After the secondary transfer, the paper is transported to the fixing device 170, where the toner image on the paper is heated and fixed to the paper, and then the paper is transported further downstream of the image forming apparatus.

[0031] When the leading edge of the paper after fixing reaches paper transport sensor 171, CPU 301 determines whether the paper should be transported to paper transport path 230 or paper transport path 231, according to instructions previously specified from operation unit 305 or PC 307 connected via external I / F 306. At this time, the destination of the paper is switched by switching the operation of transport flapper 172 according to the determination. Specifically, in the case of a double-sided printing instruction, the paper is transported to paper transport path 230, and in the case of a single-sided print or the back side of a double-sided print, the paper is transported to paper transport path 231.

[0032] The following describes the case where the paper is transported to the paper transport path 231.

[0033] The paper conveyed to paper conveying path 231 is further conveyed by conveying rollers 232 to a downstream portion of the image forming apparatus. Here, as in the switching described above, the operation of paper conveying flapper 190 is switched according to instructions previously specified from operation unit 305 or PC 307 connected via external I / F 306. This allows the configuration to switch whether the paper is conveyed to paper conveying path 180 or paper conveying path 181. If the user's designated paper output destination is paper output tray 200, the paper is conveyed to paper conveying path 180, and if the designated paper output destination is paper output tray 196, the paper is conveyed to paper conveying path 181.

[0034] The above basic image forming operation is an example, and the present invention is not limited to the above configuration.

[0035] <Explanation of remaining toner amount detection method> Next, a method for detecting the amount of remaining toner in the developing device 33 will be described with reference to Figures 2(b) and 3. Figure 2(b) is a diagram showing an example of the software configuration of the image forming apparatus 100. The functions of each software block are realized by the CPU 301 executing a program stored in the ROM 303. Note that in this embodiment, the pixel count detection unit 310, the toner remaining amount detection unit 314, and the toner replenishment control unit 315 are described as software blocks, but they may also be realized by hardware such as an ASIC.

[0036] Rotating the toner agitation screw 126 agitates the toner in the developing device 33. In this state, the toner remaining amount detection unit 314 (FIG. 2B) turns on the LED of the light-emitting element 309a of the optical sensor 309, and then detects the toner remaining amount signal using the light-receiving element 309b. The toner remaining amount signal is sampled a predetermined number of times at a predetermined sampling interval, and the remaining toner amount is determined in percentage units by detecting the High / Low pattern of the sampled toner remaining amount signal. However, when the remaining toner amount is high, the sampled toner remaining amount signal always detects a High value when light is blocked, making it impossible to determine the remaining toner amount. In this configuration, due to the mounting position and detection accuracy of the optical sensor, the remaining toner amount cannot be determined when the remaining toner amount is 60% or more, but when the remaining toner amount is less than 60%, it can be detected in 1% increments. In this embodiment, when the remaining toner amount in the developing device is 60% or more, the output of the optical sensor 309 is 60%. However, even when the remaining amount of toner in the developing device is 60% or more, the remaining amount of toner detected by the optical sensor may be notified to the remaining toner amount detection unit 314. Furthermore, in this embodiment, an example will be described in which the remaining amount cannot be detected in 1% increments when the remaining amount is 60% or more, but the remaining amount that serves as the threshold is not limited to the above.

[0037] In this embodiment, when the remaining toner amount is 60% or more, the pixel count of the printed image is used to determine the remaining toner amount. The pixel count detection unit 310 in FIG. 2(b) processes image information input from the PC 307 via the external I / F 306. The pixel count detection unit 310 detects the pixel count (i.e., the number of pixels forming the image) emitted by the laser scanner 122 in synchronization with the image formation timing, integrates the detected pixel count, and stores it in non-volatile memory 313. The amount of toner consumption can be predicted from this integrated pixel count value, and the toner remaining amount detection unit 314 reads the integrated pixel count value from the non-volatile memory 313 and converts it into the amount of toner consumption.

[0038] Immediately after a user replenishes toner, if the detection signal value of optical sensor 309 is always High, i.e., if the remaining toner amount cannot be determined as 60% or more, toner remaining amount detection unit 314 temporarily assumes the remaining amount to be 100%. After that, toner remaining amount detection unit 314 determines a predicted value of the remaining toner amount by subtracting the amount of toner consumed calculated from the integrated value of pixel count from the remaining toner amount stored in image forming apparatus 100. If the predicted value of the remaining toner amount calculated from the pixel count falls below 60%, it is fixed at 60% until the detection result of the optical sensor detects less than 60%. If the detection result of the optical sensor then falls below 60%, the remaining toner amount determined from the detection value of the optical sensor is used thereafter.

[0039] When toner is replenished, toner replenishment control unit 315 detects the amount of toner remaining after replenishment and performs processing to display the amount of toner remaining on operation unit 305. The processing performed by toner replenishment control unit 315 will be described later with reference to FIG.

[0040] <Explanation of how to detect remaining toner when replenishing toner> The operation of the device according to this embodiment will be explained using a flowchart.

[0041] Fig. 5 is a flowchart showing the processing of the image forming apparatus when a user replenishes toner from toner pack 128. Fig. 5 is executed by toner replenishment control unit 315 shown in Fig. 2(b). A program for executing the processing shown in Fig. 5 is stored in ROM 303, and is read and executed by CPU 301.

[0042] 3, the user attaches toner pack 128 to supply port 125 and operates a supply lever (not shown) to open the supply port, whereby the toner in toner pack 128 is supplied by its own weight to developing device 33. When the supply is complete, the user operates the supply lever to close the supply port and removes toner pack 128 from the supply port.

[0043] In step S501, CPU 301 determines whether supply port 125 has been opened for toner supply. The open / closed state of supply port 125 can be detected by a hardware configuration based on the High / Low level of an input port signal. When CPU 301 detects that supply port 125 has been opened, the process proceeds to step S502.

[0044] In step S502, CPU 301 determines whether or not the user has finished replenishing toner and closed replenishing port 125. If CPU 301 detects that replenishing port 125 is closed, it executes the process described in step S503.

[0045] In step S503, the CPU 301 drives the motor that serves as the drive source for the toner stirring screw 126 to start stirring the toner.

[0046] Thereafter, CPU 301 proceeds to step S504 and uses the above-described method to detect the remaining amount of toner using optical sensor 309. At this time, if the remaining amount of toner contained in developing device 33 is 60% or more, the detection value of light receiving element 309b of the optical sensor is always a detection result of High when light is blocked, and the remaining amount of toner cannot be determined.

[0047] In step S505, the CPU 301 determines whether the remaining amount of toner determined from the detection result of the optical sensor 309 is less than 60%.

[0048] If the remaining toner amount is not less than 60%, CPU 301 executes the process described in step S506. Because the remaining toner amount is indefinite, CPU 301 assumes it is 100% and displays the remaining amount on operation unit 305. FIG. 6(a) is a diagram showing an example of a screen displayed on operation unit 305 in S506. Toner remaining amount 601 displays the current remaining toner amount as a percentage. Object 603 is an object that indicates the remaining toner amount, and is filled in according to the displayed remaining toner amount. In FIG. 6(a), the remaining toner amount is 100%, so the entire object is filled in.

[0049] Next, CPU 301 executes the process described in step S507. CPU 301 clears the pixel count integrated value stored in nonvolatile memory 313 to 0. Thereafter, in step S508, CPU 301 stores a remaining toner amount value of 100% in nonvolatile memory 313.

[0050] If the remaining toner amount determined from the detection result of the optical sensor 309 in step S505 is less than 60%, the CPU 301 executes the process described in step S510. In S510, the CPU 301 displays the remaining toner amount on the operation unit 305 based on the detection result of the optical sensor. FIG. 6B is an example of a screen displayed on the operation unit 305 when the remaining toner amount detected by the optical sensor 309 is 58%. Remaining toner amount 602 displays the current remaining toner amount as a percentage. Object 604 is an object that indicates the remaining toner amount. The object 604 is filled with an amount corresponding to the detected remaining toner amount. Note that, although the present embodiment describes a case where the remaining amount is displayed in 1% increments, the remaining amount may also be displayed in predetermined percentage increments. For example, if the remaining toner amount is more than 50% but less than 60%, the remaining toner amount may be displayed as 60%.

[0051] Next, in step S508, CPU 301 stores the remaining toner value of 58% in non-volatile memory 313. After that, in step S509, CPU 301 stops the motor that drives toner stirring screw 126. This completes the process when toner is replenished.

[0052] <Explanation of how to detect remaining toner when printing> FIG. 4 is a flowchart showing the process of the image forming apparatus 100 for detecting the amount of remaining toner during printing.

[0053] A program for executing the flowchart shown in FIG. 4 is stored in the ROM 303, and the CPU 301 reads and executes the program to realize the processing.

[0054] When the CPU 301 is powered on, the process shown in FIG. 4 starts.

[0055] In step S401, the CPU 301 performs a power startup process to start supplying power to the entire device. When the power startup is complete, the CPU 301 executes the process described in step S402.

[0056] In step S402, CPU 301 determines whether or not there is a request for image formation. An image formation request is, for example, a print instruction from PC 307 or an instruction to start a copy job via operation unit 305. If it is determined in step S402 that there is a request for image formation, CPU 301 executes the process described in step S403.

[0057] In step S403, the CPU 301 drives the motor that serves as the drive source for the toner stirring screw 126 to start stirring the toner.

[0058] Next, in step S404, the CPU 301 performs image formation by controlling the image forming unit 308 and various loads 311. When image formation for one page is completed, the CPU 301 executes the process described in step S405.

[0059] In step S405, CPU 301 operates optical sensor 309 using the method described above to detect the remaining amount of toner. CPU 301 acquires the output of optical sensor 309 and determines the remaining amount of toner based on the acquired output. At this time, if the remaining amount of toner contained in developing device 33 is 60% or more, the detection value of light receiving element 309b of the optical sensor is always High, indicating that light is blocked, and the remaining amount of toner cannot be determined.

[0060] In step S406, CPU 301 determines whether the remaining amount of toner is less than 60% based on the detection result of optical sensor 309. If it is not less than 60%, CPU 301 executes the process described in step S407.

[0061] In step S407, the CPU 301 detects the pixel count of one page of image when the image is formed, adds it to the pixel count integrated value read from the nonvolatile memory 313, and stores it in the nonvolatile memory 313.

[0062] Next, in step S408, CPU 301 calculates the remaining toner amount (%) using the value obtained by converting the added pixel count integrated value into the amount of toner consumed. A more specific method is described below. CPU 301 calculates the product of the added pixel integrated value and the amount of toner consumed per pixel (%). The calculated remaining toner amount is subtracted from the remaining toner amount stored in non-volatile memory 313 to calculate a predicted remaining toner amount.

[0063] Next, in step S409, CPU 301 determines whether the predicted remaining toner amount calculated in step S408 is less than 60%. If it is 60% or more, CPU 301 executes the process described in step S410. In step S410, CPU 301 causes operation unit 305 to display the calculated predicted remaining toner amount.

[0064] On the other hand, if the predicted remaining toner amount calculated from the pixel count integrated value in step S409 is less than 60%, CPU 301 executes the process described in step S411.

[0065] Because there are variations in the detection results of the remaining toner amount due to factors such as the operating environment, such as temperature and humidity, and tolerances in the mounting position of the optical sensor 309, the detection result of the optical sensor 309 may not be less than 60% even if the actual predicted remaining toner amount is less than 60%. In this embodiment, when the remaining toner amount calculated using pixel count is less than 60%, the remaining toner amount calculated based on pixel count is not displayed, and the remaining toner amount is displayed as a constant value of 60%.

[0066] In step S411, CPU 301 sets the stored remaining toner amount to 60%. Therefore, when step S410 is executed after the process described in step S411, the remaining toner amount displayed on operation unit 305 will be 60%. Then, CPU 301 executes the process described in step S412.

[0067] In step S412, the CPU 301 determines whether there is a next page to print.

[0068] In step S406, if the remaining amount of toner determined from the detection result of optical sensor 309 is less than 60%, CPU 301 executes the process described in step S413.

[0069] In step S413, CPU 301 causes operation unit 305 to display the remaining toner amount determined based on the detection result of optical sensor 309. Thereafter, CPU 301 executes the process described in step S412.

[0070] In step S412, if there is a next page to print, CPU 301 returns the process to step S404. On the other hand, if there is not a next page to print, CPU 301 advances the process to step S414.

[0071] In step S414, the CPU 301 stops the applied high voltage and the driven motor, thereby ending the printing operation, and then the process returns to step S402.

[0072] The process shown in FIG. 4 is executed until the image forming apparatus 100 is powered off.

[0073] As shown in FIG. 4, in this embodiment, when the remaining toner amount is greater than a predetermined value, the remaining toner amount is calculated based on pixel count of the printed image. In this way, even when the remaining toner amount cannot be detected by a sensor such as an optical sensor, the amount of toner used can be displayed on the operation unit. Furthermore, in this embodiment, when the remaining toner amount is equal to or less than a predetermined value, the remaining toner amount based on the output of a sensor such as an optical sensor is displayed on the operation unit. This allows the remaining toner amount to be displayed on the operation unit more accurately than pixel count when the remaining toner amount is equal to or less than the predetermined value.

[0074] As described above, according to the present invention, even if the toner remaining amount falls within a range that the optical sensor cannot detect after toner replenishment, the remaining toner amount is predicted and displayed based on pixel count during image formation. Furthermore, if the predicted value falls below the upper limit of the remaining amount that the optical sensor can detect, the predicted value is fixed at that upper limit and displayed. After the remaining toner amount falls within a range that the optical sensor can detect, the remaining toner amount is displayed based on the detection result of the optical sensor.

[0075] Therefore, even if the remaining amount of toner is within a range where it cannot be detected by the optical sensor after toner replenishment, it is possible to display the remaining amount in multiple stages.

[0076] In this embodiment, in order to simplify the explanation, the embodiment has been described as an example of a monochrome image forming apparatus having one image forming unit 120, but similar processing can also be performed in a color image forming apparatus having multiple image forming units.

[0077] Furthermore, although this embodiment describes an example of an electrophotographic image forming apparatus that uses toner as a developer, similar processing can also be performed in an inkjet image forming apparatus that uses ink as a developer.

[0078] <Other embodiments> Needless to say, the object of the present invention can also be achieved by providing a recording medium on which program code for software that realizes the functions of the above-described embodiments is recorded to a system / device, and having a computer in the system / device read and execute the program code. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiments, and the recording medium on which the computer program code is stored constitutes the present invention.

[0079] Examples of storage media for supplying computer program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, and DVDs.

[0080] It goes without saying that this also includes cases where an operating system (OS) running on a computer performs some or all of the actual processing based on the instructions of the program code, and the functions of the above-mentioned embodiments are realized through that processing.

[0081] Furthermore, the computer program code read from the storage medium may be written to a memory provided on a function expansion board inserted into a computer or a function expansion unit connected to the computer, and then, based on the instructions of the program code, a CPU provided on the function expansion board or function expansion unit may perform some or all of the actual processing, thereby realizing the functions of the above-mentioned embodiments. [Explanation of symbols]

[0082] 120 Image forming unit 124 Photosensitive drum 125 Supply port 126 Toner stirring screw 128 toner packs 301 CPU 302 RAM 304 Power supply control means 305 Operation section 308 Image forming unit 309 Optical Sensor 310 Pixel Count Detector 313 Non-volatile memory 314 Toner remaining amount detection unit 315 Toner supply control unit

Claims

1. An image forming apparatus capable of replenishing developer without replacing a container in which the developer is held, a detecting means for detecting a remaining amount of the developer held in the image forming apparatus; a calculation means for calculating the remaining amount of the developer based on the number of pixels of the formed image; and a display means for displaying the remaining amount of the developer, The display means displays a value based on the remaining amount calculated by the calculation means when the remaining amount of the developer detected by the detection means is equal to or greater than a predetermined amount, and displays a value based on the remaining amount detected by the detection means when the remaining amount of the developer detected by the detection means is less than the predetermined amount.

2. 2. The image forming apparatus according to claim 1, wherein said detecting means detects the remaining amount of said developer based on the output of an optical sensor.

3. 2. The image forming apparatus according to claim 1, wherein the display means displays a value based on the predetermined amount when the remaining amount of the developer detected by the detection means is equal to or greater than the predetermined amount and the remaining amount of the developer calculated by the calculation means is less than the predetermined amount.

4. 2. The image forming apparatus according to claim 1, wherein the detecting means detects the remaining amount of the developer when the supply of the developer is completed.

5. 5. The image forming apparatus according to claim 4, wherein the display means displays a value based on another predetermined remaining amount when the remaining amount of the developer detected by the detection means following completion of replenishment of the developer is greater than the predetermined amount.

6. 6. The image forming apparatus according to claim 5, wherein the calculation means subtracts the amount of developer calculated based on the number of pixels from the other predetermined remaining amount to calculate the remaining amount of developer.

7. 6. The image forming apparatus according to claim 5, wherein the display means displays a value based on the remaining amount of developer detected by the detection means when the remaining amount of developer detected by the detection means following completion of replenishment of the developer is less than the predetermined amount.

8. A control method for an image forming apparatus that can replenish developer without replacing a container that holds the developer, comprising: a detecting step of detecting a remaining amount of the developer held in the image forming apparatus; a calculation step of calculating the remaining amount of the developer based on the number of pixels of the formed image; a display step of displaying the remaining amount of the developer on a display means, The control method for an image forming apparatus is characterized in that the display process displays a value based on the remaining amount calculated in the calculation process if the remaining amount of developer detected in the detection process is equal to or greater than a predetermined amount, and displays a value based on the remaining amount detected in the detection process if the remaining amount of developer detected in the detection process is less than the predetermined amount.

9. 9. The method for controlling an image forming apparatus according to claim 8, wherein the detecting step detects the remaining amount of the developer based on an output from an optical sensor.

10. 9. The control method for an image forming apparatus according to claim 8, wherein the display step displays a value based on the predetermined amount when the remaining amount of the developer detected in the detection step is equal to or greater than the predetermined amount and the remaining amount of the developer calculated in the calculation step is less than the predetermined amount.

11. 9. The method for controlling an image forming apparatus according to claim 8, wherein the detecting step detects the remaining amount of the developer when the replenishment of the developer is completed.

12. The control method for an image forming apparatus according to claim 11, wherein the display step displays a value based on another predetermined remaining amount when the remaining amount of the developer detected in the detection step executed in response to completion of replenishment of the developer is greater than the predetermined amount.

13. 13. The control method for an image forming apparatus according to claim 12, wherein the calculating step calculates the remaining amount of developer by subtracting the amount of developer calculated based on the number of pixels from the other predetermined remaining amount.

14. 13. The control method for an image forming apparatus according to claim 12, wherein the display step displays a value based on the remaining amount of developer detected in the detection step, which is executed in response to completion of replenishment of the developer, when the remaining amount of developer detected in the detection step is less than the predetermined amount.

15. A computer program that causes a computer to execute a control method for an image forming apparatus that can replenish developer without replacing a container that holds the developer, the control method comprising: a detecting step of detecting an amount of the developer held in the image forming apparatus; a calculation step of calculating the remaining amount of the developer based on the number of pixels of the formed image; a display step of displaying the remaining amount of the developer on a display means, the display step displays a value based on the remaining amount calculated in the calculation step if the remaining amount of the developer detected in the detection step is equal to or greater than a predetermined amount, and displays a value based on the remaining amount detected in the detection step if the remaining amount of the developer detected in the detection step is less than the predetermined amount.

Images