Image forming apparatus

Abstract

To notify a user of the remaining amount of toner while switching between a plurality of toner remaining amount sensors, and prevent the remaining amount of toner notified to the user from becoming discontinuous at the switching between the toner remaining amount sensors even when the toner remaining sensors have individual differences from each other.SOLUTION: A control unit 90, when the remaining amount of toner is reduced to less than 50% (S105 YES), notifies a user of the remaining amount of toner based on toner consumption estimated by pixel count (S106, S107), acquires a plurality of differences between the remaining amount of toner estimated by the pixel count and the remaining amount of toner acquired by a first remaining amount sensor 510 (S109), and when toner is supplied to a developer container 32 through a supply port after the acquisition of the plurality of differences, and the remaining amount of toner acquired by a second remaining amount sensor 550 is reduced to less than 50% again, notifies the user of the remaining amount of toner that is obtained by correcting the remaining amount of toner acquired by the first remaining amount sensor 510 by using a correction value based on the plurality of differences (S124-S126).SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus for forming an image on a recording material. [Background technology]

[0002] In general, an electrophotographic image forming apparatus forms an image by transferring a toner image formed on the surface of a photosensitive drum to a transfer material as a transfer medium. Known methods of replenishing a developer include a process cartridge method and a toner container replenishing method. In the process cartridge method, a photosensitive drum and a developing container are integrated as a process cartridge, and when the toner, which is the developer, runs out, the process cartridge is replaced with a new one. On the other hand, in the toner container replenishing method, when the toner runs out, the toner is replenished from a toner container such as a toner pack or a toner bottle to the developing container. In either of these methods, a function of displaying the remaining number of printable sheets may be added so that a user can replace the cartridge or replenish toner at an appropriate time. In order to add such a function, it is necessary to detect and predict the remaining amount of toner in the cartridge.

[0003] Various methods have been proposed to detect the amount of remaining toner, among which the light transmission type toner remaining detection method is widely used. In the light transmission type toner remaining detection method, an image forming device or the like is equipped with a light emitting element (light source) such as a light emitting diode (LED) and a light receiving element (light receiving section) such as a phototransistor. The light emitting element and the light receiving element form an optical path that passes through the developer storage chamber, and the amount of remaining toner is detected from the time when the toner blocks the optical path.

[0004] In the light transmission type toner remaining amount detection method, a light guide member on the light-emitting side and a light guide member on the light-receiving side are provided in the developer storage unit as a means for guiding the light emitted from the light-emitting element (hereinafter referred to as detection light) to the inside and outside of the developer storage chamber. The light guide member on the light-emitting side guides the detection light irradiated from the light-emitting element to the inside of the developer storage chamber. The light guide member on the light-receiving side guides the detection light that has passed through the inside of the developer storage chamber to a light-receiving element outside the developer storage chamber (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-131479 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in order to accurately detect the amount of toner remaining in the developing container from a full to a low amount, it is conceivable to improve the detection accuracy by using a plurality of toner remaining sensors. However, there are individual differences in the sensitivity of the light receiving element of the toner remaining sensor. In addition, deterioration of the light path due to the light guide and durability may cause differences in the light receiving level in each of the plurality of sensors, which may cause differences in the detection results of each toner remaining sensor. Therefore, when switching between the respective toner remaining sensors, the toner remaining amounts acquired by each sensor may not be smoothly connected at the time of switching, and discontinuous results may be notified to the user.

[0007] To provide an improved toner supply system that can be used in a variety of applications, including a mobile phone, a mobile phone, a printer, a printer for a mobile phone, a computer, a mobile phone ... [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention has the following configuration.

[0009] (1) An image forming apparatus comprising: a photosensitive drum; exposure means for forming an electrostatic latent image on the photosensitive drum by emitting light from a light source based on image information; a developing container having a supply port through which toner is replenished from outside the image forming apparatus and accommodating toner; a developing roller for developing the electrostatic latent image and forming a toner image with the toner contained in the developing container; first detection means for outputting information corresponding to the amount of toner remaining in the developing container when the amount of toner remaining in the developing container is less than a predetermined amount; second detection means for outputting information corresponding to the amount of toner remaining in the developing container when the amount of toner remaining in the developing container is equal to or greater than the predetermined amount; and counting means for estimating an amount of toner consumption based on a value obtained by counting the light emission state of the light source for each pixel based on the image information, wherein the image forming apparatus is capable of replenishing toner in a lump to the developing container via the supply port, an image forming apparatus including a control means for controlling the counting means to report the remaining toner amount based on the detection result by the second detection means, and when the remaining toner amount is less than the predetermined amount, to report the remaining toner amount based on the estimated result by the counting means or the detection result by the first detection means, wherein when the remaining toner amount falls below the predetermined amount, the control means reports the remaining toner amount based on the amount of toner consumed estimated by the counting means, and obtains a plurality of differences between the remaining toner amount measured by the counting means and the remaining toner amount measured by the first detection means, and when toner is replenished to the developing container through the supply port after obtaining the plurality of differences, and the remaining toner amount measured by the second detection means again falls below the predetermined amount, reports the remaining toner amount measured by the first detection means corrected by a correction value based on the plurality of differences.

[0010] (2) A toner image forming apparatus comprising: a photosensitive drum; an exposure unit for forming an electrostatic latent image on the photosensitive drum by emitting light from a light source based on image information; a developing container having a supply port through which toner is supplied from outside the image forming apparatus and for containing toner; a developing roller for developing the electrostatic latent image and forming a toner image with the toner contained in the developing container; a first detection unit for outputting information corresponding to the amount of toner remaining when the amount of toner remaining in the developing container is less than a predetermined amount; and a second detection unit for outputting information corresponding to the amount of toner remaining when the amount of toner remaining in the developing container is equal to or greater than the predetermined amount; an image forming apparatus capable of replenishing toner in one lump via a developing container, the image forming apparatus further comprising: a control means for controlling to notify of a remaining toner amount based on a detection result by the second detection means up to the predetermined amount, and to notify of the remaining toner amount based on the detection result by the first detection means when the remaining toner amount falls below the predetermined amount, the control means obtaining a difference between the remaining toner amount detected by the second detection means and the remaining toner amount detected by the first detection means, and notifying of a remaining toner amount obtained by correcting the remaining toner amount detected by the first detection means based on the difference, when the remaining toner amount falls below the predetermined amount. Effect of the Invention

[0011] According to the present invention, when multiple toner remaining sensors are switched to notify the remaining toner amount, even if there are individual differences between the toner remaining sensors, the remaining toner amount notified to the user can be prevented from becoming discontinuous when the toner remaining sensor is switched. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view and a perspective view showing an image forming apparatus according to a first embodiment and a second embodiment; [Diagram 2] 1 is a perspective view showing a closed state and an open state of a pressure plate of a reading device according to first and second embodiments; FIG. [Diagram 3] 1 is a cross-sectional view and a perspective view showing an image forming apparatus according to a first embodiment and a second embodiment; [Figure 4] FIG. 1 is a perspective view showing a toner pack according to first and second embodiments; [Diagram 5]FIG. 1 is a perspective view showing a developing container and a toner pack according to first and second embodiments, a front view showing the developing container and a toner pack, and a perspective view showing an agitating member. [Figure 6] 5A-5A cross-sectional view of FIG. 5(b) in Examples 1 and 2, and 5B-5B cross-sectional view of FIG. 5(b) [Figure 7] FIG. 1 is a perspective view showing a developing device according to first and second embodiments; [Figure 8] 1 is a perspective view showing a substrate and a substrate holding member according to first and second embodiments, and an exploded perspective view thereof; [Figure 9] 10B-10B cross-sectional view of the developing device of the first and second embodiments. [Figure 10] Circuit diagram showing the first remaining amount sensor and the second remaining amount sensor in the first and second embodiments. [Figure 11] FIG. 1 is a block diagram showing a control system of an image forming apparatus according to first and second embodiments. [Figure 12] 1A and 1B are cross-sectional views showing remaining toner amounts of 80%, 50%, and 10% in Examples 1 and 2. [Figure 13] Graph showing the relationship between remaining toner amount and light blocking time count in Example 1 [Figure 14] 1 is a flowchart showing a sequence for correcting individual differences in the first embodiment. [Figure 15] Graph showing the relationship between remaining toner amount and light blocking time count in Example 2 [Figure 16] 1 is a flowchart showing a sequence for correcting individual differences in the second embodiment. [Figure 17] Graph showing the relationship between remaining toner amount and light blocking time count in Example 2 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the present invention is not limited to the following embodiments. EXAMPLES

[0014] 1(a) is a schematic diagram showing the configuration of an image forming apparatus 1 according to a first embodiment. The image forming apparatus 1 is a monochrome printer that forms an image on a recording material based on image information input from an external device. The recording material includes various sheet materials of different materials, such as paper such as plain paper and thick paper, plastic films such as sheets for overhead projectors, sheets of special shapes such as envelopes and index paper, and cloth.

[0015] [Overall configuration] The image forming apparatus 1 has a printer main body 100 which is the device main body, a reading device 200 supported by the printer main body 100 so as to be openable and closable, an operation unit 300 attached to the exterior surface of the printer main body 100, and a toner remaining amount panel 400. The printer main body 100 has an image forming unit 10 which forms a toner image on a recording material, a feeding unit 60 which feeds the recording material to the image forming unit 10, a fixing unit 70 which fixes the toner image formed by the image forming unit 10 onto the recording material, and a pair of discharge rollers 80.

[0016] The operation unit 300 has a display unit 301 (see FIG. 11) such as a liquid crystal screen, and an operation unit such as a touch panel and buttons. The operation unit 300 displays the status of the image forming apparatus 1, messages to the user, and the like. The messages to the user include information on the remaining toner amount (such as the remaining %), information on the operation procedure when replenishing toner, and the like. The operation unit 300 accepts operations from the user to the image forming apparatus 1. The toner remaining amount panel 400 has, for example, a plurality of light-emitting elements arranged vertically, and notifies the user of the remaining toner amount by changing the number of light-emitting elements that emit light according to the remaining toner amount. The toner remaining amount panel 400 may be configured to, for example, blink the light-emitting elements when the remaining toner amount becomes low.

[0017] The image forming section 10 has a scanner unit 11, an electrophotographic process unit 20, and a transfer roller 12 that transfers a toner image, which is a developer image formed on a photosensitive drum 21 of the process unit 20, to a recording material. The process unit 20 has the photosensitive drum 21 and a developing device 30 including a charging roller 22, a pre-exposure device 23, and a developing roller 31 arranged around the photosensitive drum 21. The process unit 20 is detachably attached to the printer body 100. The process unit 20 may be screwed to the printer body 100, and may be removed mainly by a serviceman rather than a user.

[0018] The photosensitive drum 21 is a cylindrically shaped photosensitive member. The photosensitive drum 21 of the first embodiment has a photosensitive layer formed of a negatively charged organic photosensitive member on a drum-shaped base body formed of aluminum. The photosensitive drum 21, which is an image carrier, is rotated by a motor in a predetermined direction (clockwise direction in the figure) at a predetermined process speed.

[0019] The charging roller 22 comes into contact with the photosensitive drum 21 with a predetermined pressure contact force to form a charging portion. A desired charging voltage is applied by a charging high-voltage power supply to uniformly charge the surface of the photosensitive drum 21 to a predetermined potential. In the first embodiment, the photosensitive drum 21 is negatively charged by the charging roller 22. The pre-exposure device 23 neutralizes the surface potential of the photosensitive drum 21 before it enters the charging portion in order to generate a stable discharge in the charging portion.

[0020] The scanner unit 11, which is an exposure means, has a light source and uses a rotating polygonal mirror to irradiate the photosensitive drum 21 with laser light L corresponding to image information input from an external device or a reading device 200, thereby scanning and exposing the surface of the photosensitive drum 21. By this exposure, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 21.

[0021] The developing device 30 includes a developing roller 31 which is a toner carrier that carries toner as a developer, a developing container 32 which is a frame of the developing device 30, and a supply roller 33 which can supply toner to the developing roller 31. The developing roller 31 and the supply roller 33 are rotatably supported by the developing container 32. The developing roller 31 is disposed at an opening of the developing container 32 so as to face the photosensitive drum 21. The supply roller 33 is in rotatable contact with the developing roller 31, and the toner contained in the developing container 32 is applied to the surface of the developing roller 31 by the supply roller 33.

[0022] The developing device 30 of the first embodiment uses a contact development method as a developing method. That is, a toner layer carried by the developing roller 31 comes into contact with the photosensitive drum 21 in a developing section (developing area) where the photosensitive drum 21 and the developing roller 31 face each other. A developing voltage is applied to the developing roller 31 by a developing high voltage power supply. Under the developing voltage, the toner carried by the developing roller 31 is transferred from the developing roller 31 to the surface of the photosensitive drum 21 according to the potential distribution on the surface of the photosensitive drum 21, and the electrostatic latent image is developed into a toner image.

[0023] An agitating member 34 is provided inside the developing container 32. The agitating member 34 is driven to rotate by a motor M1 (see FIG. 11), thereby agitating the toner in the developing container 32 and transporting the toner toward the developing roller 31 and the supply roller 33. In addition, the agitating member 34 circulates, within the developing container 32, the toner that has not been used for development and has been peeled off from the developing roller 31, thereby making the toner in the developing container 32 uniform.

[0024] In addition, a developing blade 35 that regulates the amount of toner carried by the developing roller 31 is disposed at the opening of the developing container 32 in which the developing roller 31 is disposed. The toner supplied to the surface of the developing roller 31 passes through the portion facing the developing blade 35 as the developing roller 31 rotates, whereby the toner is uniformly formed into a thin layer and is negatively charged by frictional charging.

[0025] 1(a) and 1(b), the feeding section 60 has a front door 61 supported by the printer body 100 so as to be openable and closable, a tray section 62, a middle plate 63, a tray spring 64, and a pickup roller 65. The tray section 62 constitutes the bottom surface of a storage space that stores recording materials and is revealed when the front door 61 is opened, and the middle plate 63 is supported by the tray section 62 so as to be movable up and down. The tray spring 64 biases the middle plate 63 upward, and presses the recording materials P loaded on the middle plate 63 against the pickup roller 65. The front door 61 closes the storage space when closed relative to the printer body 100, and supports the recording materials P together with the tray section 62 and the middle plate 63 when opened relative to the printer body 100.

[0026] The fixing unit 70 is a thermal fixing type that fixes an image by heating and melting unfixed toner on a recording material. The fixing unit 70 includes a fixing film 71, a fixing heater such as a ceramic heater that heats the fixing film 71, a thermistor that measures the temperature of the fixing heater, and a pressure roller 72 that is pressed against the fixing film 71.

[0027] [Image formation operation] Next, an image forming operation of the image forming apparatus 1 will be described. When an image formation command is input to the image forming apparatus 1, an image forming process is started by the image forming section 10 based on image information input from an external computer or a reading device 200 connected to the image forming apparatus 1. The scanner unit 11 irradiates a laser beam toward the photosensitive drum 21 based on the input image information. At this time, the photosensitive drum 21 is charged in advance by the charging roller 22, and an electrostatic latent image is formed on the photosensitive drum 21 by irradiating it with the laser beam. Thereafter, the electrostatic latent image is developed by the developing roller 31, and a toner image is formed on the photosensitive drum 21.

[0028] In parallel with the above-mentioned image forming process, the pickup roller 65 of the feeding section 60 feeds out the recording material P supported by the front door 61, the tray section 62, and the middle plate 63. The recording material P is fed to the pair of registration rollers 15 by the pickup roller 65, and the skew of the recording material P is corrected by hitting the nip portion of the pair of registration rollers 15. The pair of registration rollers 15 is then driven in accordance with the transfer timing of the toner image, and conveys the recording material P toward the transfer nip portion formed by the transfer roller 12 and the photosensitive drum 21.

[0029] A transfer voltage is applied to the transfer roller 12, which is a transfer means, from a transfer high voltage power supply, and the toner image carried on the photosensitive drum 21 is transferred to the recording material P being transported by a pair of registration rollers 15. The recording material P with the transferred toner image is transported to a fixing section 70, where the toner image is heated and pressurized as it passes through a nip between a fixing film 71 and a pressure roller 72 of the fixing section 70. This causes the toner particles to melt and then adhere, thereby fixing the toner image to the recording material P. The recording material P that has passed through the fixing section 70 is discharged to the outside of the image forming apparatus 1 (outside the machine) by a pair of discharge rollers 80, and is loaded onto a discharge tray 81 formed on the top of the printer main body 100.

[0030] The discharge tray 81 is inclined upward toward the downstream in the discharge direction of the recording material P, and the recording material P discharged to the discharge tray 81 slides down the discharge tray 81, so that the rear end of the recording material P is aligned by a regulating surface 84. Note that the image forming apparatus 1 may be a color printer.

[0031] 2(a) and 2(b), the reading device 200 has a reading unit 201 with a built-in reading section (not shown), and a pressure plate 202 supported by the reading unit 201 so as to be openable and closable. On the upper surface of the reading unit 201, there is provided a document table glass 203 which transmits light emitted from the reading section and on which a document is placed.

[0032] As shown in FIGS. 3(a) and 3(b), a first opening 101 that opens upward is formed in the upper part of the printer body 100, and is covered by a discharge tray 81. The discharge tray 81 is supported so as to be openable and closable with respect to the printer body 100 around a rotation axis extending in the left-right direction. The left-right direction here refers to the direction when the operation unit 300 is viewed from the front. The discharge tray 81 is opened from the front side to the back side when the reading device 200 is opened with respect to the printer body 100. In addition, the first opening 101 is configured to expose a supply protrusion 37 (see FIG. 5) having a supply port to which the toner pack 40 in FIG. 4 can be attached. A user can access the supply protrusion 37 by opening the discharge tray 81.

[0033] In this manner, in the first embodiment, a method is adopted in which the user replenishes toner from the toner pack 40 filled with replenishment toner to the developing device 30 while the developing device 30 is still attached to the image forming apparatus 1 (see FIGS. 1(a) and 1(b)). This method is called a direct replenishment method.

[0034] [Recovery of residual toner after transfer] The first embodiment employs a cleaner-less configuration in which toner remaining on the photosensitive drum 21 without being transferred to the recording material P (hereinafter, referred to as transfer residual toner) is collected in the developing device 30 and reused. The transfer residual toner is removed by the following process.

[0035] The residual toner includes a mixture of positively charged toner and negatively charged toner that does not have a sufficient charge. The photosensitive drum 21 after transfer is neutralized by the pre-exposure device 23, and the charging roller 22 generates a uniform discharge, so that the residual toner is charged negatively again. The residual toner that has been charged negatively again in the charging section reaches the developing section as the photosensitive drum 21 rotates. Then, the surface area of ​​the photosensitive drum 21 that has passed the charging section is exposed by the scanner unit 11 with the residual toner still attached to the surface, and an electrostatic latent image is written thereon.

[0036] Here, the behavior of the transfer residual toner that has reached the development section will be explained separately for the exposed and non-exposed sections of the photosensitive drum 21. The transfer residual toner adhering to the non-exposed section of the photosensitive drum 21 is transferred to the development roller 31 in the development section due to the potential difference between the potential (dark section potential) of the non-exposed section of the photosensitive drum 21 and the development voltage, and is collected in the development container 32. This is because the normal charging polarity of the toner is negative, and the development voltage applied to the development roller 31 is positive relative to the potential of the non-exposed section. The toner collected in the development container 32 is agitated and dispersed with the toner in the development container 32 by the agitation member 34, and is carried by the development roller 31 for use again in the development process.

[0037] On the other hand, the transfer residual toner adhering to the exposed portion of the photosensitive drum 21 does not transfer from the photosensitive drum 21 to the developing roller 31 in the developing portion, but remains on the surface of the photosensitive drum 21. This is because the normal charging polarity of the toner is negative, and the developing voltage applied to the developing roller 31 has a potential that is more negative than the potential of the exposed portion (bright portion potential). The transfer residual toner remaining on the surface of the photosensitive drum 21 is carried by the photosensitive drum 21 together with other toner transferred from the developing roller 31 to the exposed portion, and moves to the transfer portion, where it is transferred to the recording material P.

[0038] In this manner, in the first embodiment, a cleaner-less configuration is adopted in which the transfer residual toner is collected in the developing device 30 and reused. However, a conventionally known configuration may be adopted in which the transfer residual toner is collected using a cleaning blade that contacts the photosensitive drum 21.

[0039] [Developer container and toner pack configuration] Next, the configurations of the developing container 32 and the toner pack 40, which is a supply container, will be described. Fig. 5(a) is a perspective view showing the developing container 32 and the toner pack 40, and Fig. 5(b) is a front view showing the developing container 32 and the toner pack 40. Fig. 5(c) is a perspective view showing the stirring member 34 in the developing container 32. Fig. 6(a) is a cross-sectional view taken along line 5A-5A in Fig. 5(b), and Fig. 6(b) is a cross-sectional view taken along line 5B-5B in Fig. 5(b).

[0040] As shown in Fig. 5(a) to Fig. 6(b), the developing container 32 as a part of the developing device 30 has a transport chamber 36 that houses an agitating member 34. The transport chamber 36 as a container that houses toner extends over the entire length of the developing container 32 in the longitudinal direction LD (left-right direction). The longitudinal direction LD is also the direction of the rotation axis of the photosensitive drum 21. The developing container 32 is configured by connecting a developing container frame 320 and a developing container lid 321 by a connecting portion 322. The developing roller 31 and the supply roller 33 are supported rotatably with respect to the developing container frame 320.

[0041] Further, the developing container 32 has a supply protrusion 37 that protrudes upward from one end in the longitudinal direction of the transport chamber 36 and communicates with the transport chamber 36. More specifically, the supply protrusion 37 is provided at one end of the developing container lid 321 in the rotational axis direction (longitudinal direction LD) of the developing roller 31, and protrudes toward the discharge tray 81 in a direction intersecting the rotational axis direction beyond the center of the developing container 32.

[0042] In the first embodiment, the supply protrusion 37 is formed to have a hollow interior, and is disposed on the left side of the developing container 32. An attachment portion 57 to which the toner pack 40 can be attached is provided at the end of the supply protrusion 37, and a rotatable supply port 32a is disposed in the attachment portion 57 so that the toner pack 40 can be replenished from the toner pack 40 to the transport chamber 36. The toner pack 40 can be attached to the attachment portion 57 in a state where it is exposed to the outside of the device.

[0043] The supply protrusion 37 extends obliquely from the transport chamber 36 toward the front and upward of the device. That is, the supply protrusion 37 protrudes toward the downstream and upward in the discharge direction of the discharge roller pair 80. Therefore, the supply port 32a arranged in the supply protrusion 37 is arranged on the front side of the image forming device 1, and the work of supplying toner to the developing container 32 can be easily performed. In addition, by providing the supply protrusion 37 where the supply port 32a is arranged on one side in the longitudinal direction of the developing container 32, a space (laser passing space) through which the laser emitted from the scanner unit 11 can pass can be secured, and the image forming device 1 can be made compact.

[0044] As shown in Figs. 5(a) to 6(b), the toner pack 40 is configured to be detachably attached to the mounting portion 57 of the supply protrusion 37. The toner pack 40 has an openable / closable shutter member 41 provided at the opening, and a groove portion 42 formed corresponding to the protrusion 32b formed on the mounting portion 57. When replenishing toner to the developing container 32, the user aligns the groove portion 42 of the toner pack 40 so that it passes through the protrusion 32b of the mounting portion 57, and connects the toner pack 40 to the mounting portion 57. In this state, when the shutter member 41 of the toner pack 40 is rotated 90 degrees via a lever (not shown) provided on the image forming apparatus 1, the supply port 32a also rotates together with the shutter member 41 and abuts against an abutment portion (not shown) of the mounting portion 57. As a result, the shutter member 41 is completely opened, and the supply port 32a and the opening of the toner pack 40 communicate with each other. As a result, the toner contained in the toner pack 40 leaks out from the opening of the toner pack 40, and the leaked toner passes through the replenishing port 32a and the hollow replenishing protrusion 37 and enters the transport chamber .

[0045] Here, as shown in FIG. 5(c), the stirring member 34 has a stirring shaft 34a extending in the longitudinal direction LD, and a first blade portion 34b1 and a second blade portion 34b2 extending radially outward from the stirring shaft 34a. The first blade portion 34b1 and the second blade portion 34b2 are flexible sheets, and have different lengths extending radially outward. The first blade portion 34b1 is longer than the second blade portion 34b2. In FIG. 6(a)(b), the rotation trajectory of the first blade portion 34b1 is indicated as Tb1, and the rotation trajectory of the second blade portion 34b2 is indicated as Tb2.

[0046] As shown in FIG. 6A, the toner supplied from the supply port 32a arranged on the upstream side in the conveying direction of the agitating member 34 is sent toward the developing roller 31 and the supply roller 33 as the agitating member 34 rotates. The conveying direction of the agitating member 34 is parallel to the longitudinal direction LD of the developing container 32 (see FIG. 5A). The supply port 32a and the supply protrusion 37 are arranged at one end of the developing container 32 in the longitudinal direction LD, but the toner is distributed over the entire length of the developing container 32 by repeatedly rotating the agitating member 34. Here, as shown by the rotation trajectories Tb1 and Tb2, the first blade portion 34b1, which is the longer blade portion, functions as a main portion that conveys the toner toward the developing roller 31 and the supply roller 33. The second blade portion 34b2, which is the shorter blade portion, functions as an auxiliary portion for transporting toner at, for example, a corner portion 36e of the transport chamber 36, where the first blade portion 34b1 hits the toner and cannot transport it properly.

[0047] [How to detect remaining toner] From here, the configuration of the developing device 30 relating to the toner remaining amount detection of the first embodiment will be described in more detail with reference to Figs. 7 to 12. Fig. 7 is a perspective view showing the developing device 30. Fig. 8(a) is a perspective view showing the state in which the substrate 700 and the substrate holding member 710 are assembled to the developing container lid 321. Fig. 8(b) is a perspective view showing the substrate 700 and the substrate holding member 710. Fig. 9(a) is a cross-sectional view passing through the light-emitting elements 510a and 550a of the developing device 30, and Fig. 9(b) is a cross-sectional view taken along line 10B-10B of Fig. 9(a). Fig. 10 is a circuit diagram showing an example of the circuit configuration of the toner remaining amount sensor 500.

[0048] As shown in FIG. 7, the developing container lid 321 constituting a part of the developing container 32 has substrate positioning members 321a and 321b and substrate fixing portions 321c and 321d. Light guide members 600 and 650 are installed at positions between the substrate fixing portion 321c and the substrate fixing portion 321d of the developing container lid 321. The light guide members 600 and 650 have light emitting side light guide members 610 and 660 and light receiving side light guide members 620 and 670, respectively. The light emitting side light guide members 610 and 650 guide the light emitted from the light emitting elements 510a and 550a, respectively, into the transport chamber 36 of the developing container 32. The light receiving side light guide members 620 and 670 guide the light that has passed through the light emitting side light guide member 610 and the spatial optical paths Q and R (see FIG. 9(a) and (b)) in the transport chamber 36 to the light receiving elements 510b and 550b, respectively. The light-guiding member 600, the light-emitting element 510a, and the light-receiving element 510b are collectively referred to as a first remaining amount sensor 510, which is a first detection means. The light-guiding member 650, the light-emitting element 550a, and the light-receiving element 550b are collectively referred to as a second remaining amount sensor 550, which is a second detection means.

[0049] In the first embodiment, as shown in FIG. 8(a), a substrate 700 and a substrate holding member 710 are attached to the developer container lid 321. The substrate holding member 710 is attached to the developer container lid 321 while being sandwiched between the developer container lid 321 and the substrate 700. As shown in FIG. 8(b), the substrate 700 is provided on a surface facing the substrate holding member 710 and has light emitting elements 510a and 550a and light receiving elements 510b and 550b for detecting the remaining amount of toner in the conveying chamber 36. In the first embodiment, LEDs are used for the light emitting elements 510a and 550a, and phototransistors that are turned on by light from the LEDs are used for the light receiving elements 510b and 550b. In addition, a cable connector 700n is provided on the substrate 700, and is connected to a control unit 90 (described later) provided in the printer main body 100 by a cable. The board 700 also has positioning holes 700a, 700b into which the board positioners 321a, 321b are inserted and engaged, and board fixing holes 700c, 700d through which screws that are screwed into the board fixing portions 321c, 321d can pass.

[0050] Similarly, the substrate holding member 710 has positioning holes 710a, 710b into which the substrate positioning members 321a, 321b are inserted and engaged, and substrate fixing holes 710c, 710d through which the screws screwed into the substrate fixing members 321c, 321d can pass. Furthermore, the substrate holding member 710 has a first hole 711a into which the light guiding member 610 on the light emitting side of the light guiding member 600 is inserted, and a second hole 711b into which the light guiding member 620 on the light receiving side of the light guiding member 600 is inserted. The first hole 711a and the second hole 711b have a cylindrical shape. The substrate holding member 710, which is a holder, holds the substrate 700.

[0051] Furthermore, with the substrate holding member 710 and the substrate 700 positioned relative to the developing container lid 321, screws are inserted into the substrate fixing holes 700c, 700d, 710c, and 710d, and the screws are screwed into the substrate fixing portions 321c and 321d of the developing container lid 321. As a result, the substrate holding member 710 and the substrate 700 are fastened together to the developing container lid 321 by the screws, and the substrate holding member 710 and the substrate 700 are fixed to the developing container lid 321.

[0052] As shown in FIG. 7 to FIG. 9(b), when the substrate holding member 710 and the substrate 700 are assembled to the developing container lid 321, the light guiding members 610 and 660 on the light emitting side of the light guiding members 600 and 650 are inserted into the first hole portions 711a and 751a of the substrate holding member 710, respectively. Then, the light guiding members 610 and 660 on the light emitting side are positioned at positions close to the light emitting elements 510a and 550a of the substrate 700. Similarly, the light guiding members 620 and 670 on the light receiving side of the light guiding members 600 and 650 are inserted into the second hole portions 711b and 751b of the substrate holding member 710. Then, the light guiding members 620 and 670 on the light receiving side are positioned at positions close to the light receiving elements 510b and 550b of the substrate 700.

[0053] As described above, since the substrate holding member 710 and the substrate 700 are accurately positioned on the developing container lid 321, the light emitted from the light emitting elements 510a, 550a is reliably guided by the light guiding members 610, 660 on the light emission side. Then, the light guided by the light guiding members 610, 660 on the light emission side to the transport chamber 36 inside the developing container 32 is emitted from the light guiding members 610, 660 on the light emission side toward the longitudinal direction LD.

[0054] Then, the light traveling through the spatial light path Q or the spatial light path R inside the transfer chamber 36 is guided to the outside of the developing container 32 by the light-receiving side light-guiding members 620, 670. Since the light-receiving side light-guiding members 620, 670 are disposed close to the light-receiving elements 510b, 550b, the light emitted from the light-receiving side light-guiding members 620, 670 is reliably received by the light-receiving elements 510b, 550b.

[0055] Here, the arrangement of the light emitting elements 510a, 550a and the light receiving elements 510b, 550b will be described in more detail. As shown in Fig. 9(a) and (b), the light emitting elements 510a, 550a and the light receiving elements 510b, 550b are arranged on the side 36a of the developing container 32 opposite to the developing roller 31. The light emitting elements 510a, 550a and the light receiving elements 510b, 550b are provided in the central portion of the conveying chamber 36 in the longitudinal direction LD. More specifically, as shown in Fig. 9(b), the light emitting elements 510a, 550a and the light receiving elements 510b, 550b are arranged such that the central portion 31a (broken line) of the developing roller 31 is located between the light emitting elements 510a, 550a and the light receiving elements 510b, 550b in the longitudinal direction LD.

[0056] In this way, by providing the light emitting elements 510a, 550a and the light receiving elements 510b, 550b in the central portion of the transport chamber 36, it is possible to effectively detect the remaining amount of toner in the transport chamber 36. That is, although the developer may be unevenly distributed at the ends of the transport chamber 36 in the longitudinal direction LD, the developer is less unevenly distributed in the central portion of the transport chamber 36, so that the actual remaining amount of toner can be detected.

[0057] 10, transistors 520 and 530, which function as switches, are provided between light-emitting elements 510a and 550a and power supply voltage Vcc. An ON / OFF signal is input from control unit 90 to base terminals of transistors 520 and 530. By turning on transistors 520 and 530, a voltage from power supply voltage Vcc is applied to light-emitting elements 510a and 550a, and light-emitting elements 510a and 550a become conductive.

[0058] The light-emitting elements 510a and 550a are connected to a power supply voltage Vcc and current limiting resistors R1 and R3, and the light-emitting elements 510a and 550a emit light with a current determined by the current limiting resistors R1 and R3. The light emitted from the light-emitting elements 510a and 550a passes through optical paths Q and R as shown in FIG. 9(b) and is received by the light-receiving elements 510b and 550b. The collector terminals of the light-receiving elements 510b and 550b are connected to the power supply voltage Vcc, and the emitter terminals are connected to detection resistors R2 and R4. The light-receiving elements 510b and 550b, which are phototransistors, receive the light emitted from the light-emitting elements 510a and 550a and output a signal (current) according to the amount of light received. This signal is converted to voltages V1 and V2 by the detection resistors R2 and R4, and input to the A / D conversion unit 95 of the control unit 90 (see FIG. 11). That is, the light receiving elements 510b and 550b change their output values ​​in accordance with the amount of toner (developer) contained in the transport chamber .

[0059] As shown in FIG. 9A, the optical paths Q and R of the toner remaining amount sensor 500 are set to overlap with the rotation loci Tb1 and Tb2 of the agitating member 34 when viewed in the axial direction of the rotation shaft of the agitating member 34. In other words, the light emitted from the light emitting elements 510a and 550a of the toner remaining amount sensor 500 passes through the inside of the conveying chamber 36 within the rotation loci Tb1 and Tb2 of the agitating member 34 when viewed in the axial direction of the agitating member 34. As described above, the first remaining amount sensor 510 is the path of the light emitting element 510a, the light receiving element 510b, and the optical path Q, and the second remaining amount sensor 550 is the path of the light emitting element 550a, the light receiving element 550b, and the optical path R. The first remaining amount sensor 510 and the second remaining amount sensor 550 are included in the toner remaining amount sensor 500.

[0060] [Image forming device control system] FIG. 11 is a block diagram showing a control system of the image forming apparatus 1. The control unit 90, which is a control means of the image forming apparatus 1, has a CPU 91, which is a calculation device, a RAM 92 used as a work area of ​​the CPU 91, and a ROM 93, which is a storage unit that stores various programs. The control unit 90 also has an I / O interface 94 as an input / output port connected to an external device, an A / D conversion unit 95 that converts an analog signal into a digital signal, and a counter 97 used when estimating the toner consumption amount. The counter 97 is used to estimate the toner consumption amount based on an ON count value that is counted, accumulated, and added when the laser light is irradiated from the scanner unit 11 to the photosensitive drum 21 based on image information during image formation. The control unit 90 estimates the toner consumption amount using the counter 97 and estimates the remaining toner amount from the toner consumption amount, which will be expressed below as remaining amount detection by pixel count. The control unit 90 also functions as a counting means for performing remaining amount detection by pixel count. It is assumed that the amount of toner consumed per count is known in advance when estimating the toner consumption amount.

[0061] The input side of the control unit 90 is connected to the toner remaining amount sensor 500, the mounting sensor 53, and the opening / closing sensor 54, and the mounting sensor 53 detects that the toner pack 40 is mounted in the supply port 32a of the developing container 32. For example, the mounting sensor 53 is provided in the supply port 32a and is composed of a pressure-sensitive switch that outputs a detection signal when pressed by a protrusion of the toner pack 40. The opening / closing sensor 54 detects whether the discharge tray 81 is opened or not. The opening / closing sensor 54 is composed of, for example, a pressure-sensitive switch or a magnetic sensor.

[0062] The control unit 90 (CPU 91) judges whether the light receiving elements 510b, 550b have received light from the light emitting elements 510a, 550a based on the voltage level input from the toner remaining sensor 500. Then, the control unit 90 (CPU 91) calculates the length of time during which the toner remaining sensor 500 detected light or the length of time during which the light was blocked when the toner in the developing container 32 was stirred for a certain period of time by the stirring member 34. Here, it is estimated that the longer the time during which the light was detected or the shorter the time during which the light was blocked, the less toner there is.

[0063] The ROM 93 stores in advance, as a table, thresholds (hereinafter referred to as judgment thresholds) for judging the remaining toner amount from the time when light is detected by the toner remaining amount sensor 500 (hereinafter referred to as light detection time) or the time when light is blocked (hereinafter referred to as light blocking time). This table is hereinafter referred to as a judgment threshold table 96. The control unit 90 predicts / calculates (obtains) the remaining toner amount in the developing container 32 based on the input to the A / D conversion unit 95 and the judgment threshold table 96 stored in the ROM 93.

[0064] [Control of remaining amount detection] The control of toner remaining amount detection will be specifically described with reference to Figures 12(a), (b), (c) and Figures 13(a) and (b). Figure 12(a) shows a state where the amount of toner remaining in the developing container 32 is large, that is, about 80%. Figure 12(b) shows a state where the amount of toner remaining in the developing container 32 is about 50%. Figure 12(c) shows a state where the amount of toner remaining in the developing container 32 is small, that is, 10%.

[0065] 12(a), (b), and (c) show the same state of the rotation phase of the agitating member 34. Also, FIG. 13(a) and (b) are graphs with the vertical axis representing the light blocking time count (hereinafter referred to as the light blocking time count) when the toner remaining amount sensor 500 blocks light during one rotation of the agitating member 34. The vertical axis represents the light blocking time count value over a certain period of time, and the horizontal axis represents the remaining toner amount (%) in the developing container 32. The horizontal axis also shows 80%, 50%, and 10% corresponding to FIG. 12(a), (b), and (c). As the number of printed sheets increases, the remaining toner amount shown on the horizontal axis decreases. Therefore, the value of the light blocking time count on the vertical axis tends to decrease as the remaining toner amount decreases.

[0066] In Fig. 12(a), the amount of remaining toner is large, so the time during one rotation of the agitating member 34 during which the light of the remaining toner sensor 500 is blocked is long, resulting in a large value for the light blocking time count. On the other hand, in Fig. 12(c), the amount of remaining toner is small, so the time during one rotation of the agitating member 34 during which the light of the remaining toner sensor 500 is blocked is short, resulting in a small value for the light blocking time count. The light blocking time count can be said to be information corresponding to the amount of toner.

[0067] Incidentally, since the second remaining amount sensor 550 is disposed at a position close to the replenishing port 32a above the developing container 32, it can accurately detect the toner in the developing container 32 when the remaining amount of toner is large as shown in FIG. 12(a). FIG. 12(c) shows a state in which the toner is lifted by the first blade portion 34b1 and the second blade portion 34b2 in the rotation phase of the stirring member 34 when the remaining amount of toner is small (10%). However, in the state shown in FIG. 12(c), the toner is not lifted to the upper part of the developing container 32 even when stirred. Therefore, the optical path of the second remaining amount sensor 550 is not blocked. That is, even if the remaining amount of toner is as small as 10% but toner remains, the second remaining amount sensor 550 is not blocked and cannot detect the toner.

[0068] On the other hand, the first remaining amount sensor 510 is disposed below the developing container 32, and can accurately detect the toner when the remaining toner amount is low (10%) as shown in Fig. 12(c). However, when the remaining toner amount is high (80%) as shown in Fig. 12(a), the toner is packed tightly below the developing container 32, and even if the toner is stirred, there is almost no time for the first remaining amount sensor 510 to transmit light. Therefore, even if the remaining toner amount is reduced, the transmission cannot be detected, and the light blocking time becomes long.

[0069] That is, as shown in Fig. 13(a), the second remaining amount sensor 550 can correctly detect a state where the remaining amount of toner is large (80%), but cannot accurately count the light blocking time when the remaining amount of toner is small (10%) because the light blocking time is short. Also, the first remaining amount sensor 510 can correctly detect a state where the remaining amount of toner is small (10%), but cannot accurately count the light blocking time when the remaining amount of toner is large (80%) because the light blocking time is long. For this reason, the second remaining amount sensor 550 is used to detect the remaining amount of toner in the section where there is a lot of toner, and when the remaining amount of toner reaches about 50%, the first remaining amount sensor 510 is used to detect the remaining amount of toner.

[0070] Furthermore, there are individual variations in the light emitting element 510a and the light receiving element 510b of the first remaining amount sensor 510, and the light emitting element 550a and the light receiving element 550b of the second remaining amount sensor 550. When the toner remaining amount is half (50%) as shown in FIG. 12(b), even if the toner remaining amount is the same, there are individual differences between the first remaining amount sensor 510 and the second remaining amount sensor 550, and a difference Δα0 occurs in the light blocking time count. FIG. 13(a) also shows the difference Δα0 in the light blocking time count of the first remaining amount sensor 510 compared to the second remaining amount sensor 550 when the toner remaining amount is 50%. Note that Δα1 will be described later.

[0071] When the toner remaining amount is estimated using the second remaining amount sensor 550 in a section where the toner amount is large, and the toner remaining amount is estimated using the first remaining amount sensor 510 in a section where the toner amount is small, the second remaining amount sensor 550 is switched to the first remaining amount sensor 510 at a predetermined timing. That is, when the toner remaining amount is half (50%) as shown in FIG. 12(b), a difference of difference Δα0 occurs when switching from the light blocking time count of the second remaining amount sensor 550 to the light blocking time count of the first remaining amount sensor 510. Note that when expressing the difference between the light blocking time count of the second remaining amount sensor 550 and the light blocking time count of the first remaining amount sensor 510 without specifying what percentage the toner remaining amount is, it is simply referred to as difference Δα.

[0072] This difference causes the controller 90 to acquire a value indicating a sudden change in the remaining toner amount when the toner remaining amount shifts from the second remaining toner amount sensor 550 to the first remaining toner amount sensor 510 when the remaining toner amount is 50%, and this value is reflected as a display on the remaining toner amount panel 400. In other words, this causes the user to be notified of a sudden change in the remaining toner amount.

[0073] [Correction of individual differences in sensors] Therefore, in the first embodiment, a method for correcting the difference Δα in the light blocking time count due to individual variations between the first remaining amount sensor 510 and the second remaining amount sensor 550 will be specifically described using the flowchart in FIG.

[0074] In step (hereinafter referred to as S) 101, the user sets up the initial printer body 100. In the initial state when the printer body 100 is purchased by the user, the remaining toner amount stored in the developing container 32 is 80% or more. In S102, the user starts printing. In S103, the control unit 90 detects the remaining toner amount using the second remaining amount sensor 550. In S104, the control unit 90 notifies the user of the remaining toner amount based on the detection result of the second remaining amount sensor 550. The means for notifying the user is the display unit 301 of the operation unit 300, but may also be on the screen of a personal computer connected to the image forming apparatus 1.

[0075] In S105, the control unit 90 determines whether the remaining toner amount acquired by the second remaining amount sensor 550 is less than 50% (less than the predetermined amount), which corresponds to a predetermined amount. If the control unit 90 determines in S105 that the remaining toner amount acquired by the second remaining amount sensor 550 is not less than 50%, the process returns to S102. As long as the user continues printing and the remaining toner amount does not become less than 50%, the second remaining amount sensor 550 continues to detect the remaining toner amount.

[0076] In S105, when the control unit 90 determines that the remaining toner amount is less than 50%, the control unit 90 advances the process to S106. In S106, the control unit 90 estimates the toner consumption amount by the counter 97 described in FIG. 11, and performs toner remaining amount detection by pixel counting to estimate the remaining toner amount. That is, the control unit 90 obtains the remaining toner amount by subtracting the toner consumption amount estimated by pixel counting from the remaining toner amount at 50% detected by the second remaining amount sensor 550. In S107, the control unit 90 notifies the user of the remaining toner amount obtained by pixel counting. In the first embodiment, when the remaining toner amount is less than 50%, the detection means for the remaining toner amount used for the notification is not switched from the second remaining amount sensor 550 to the first remaining amount sensor 510, but is switched to the remaining toner amount detection by pixel counting. The following describes the detection of the remaining toner amount by pixel counting in S106.

[0077] (Switching the method for detecting remaining toner) The counter 97 is a method for estimating the amount of toner consumption, and does not directly detect the actual amount of toner remaining in the developing container 32. Therefore, the accuracy of estimating the amount of toner consumption may be lower than that of the first remaining amount sensor 510 and the second remaining amount sensor 550.

[0078] However, when the toner remaining amount is less than 50%, the accuracy of detecting the remaining amount of toner by the second remaining amount sensor 550 decreases, so the method of detecting the remaining amount of toner is switched from the second remaining amount sensor 550 to pixel counting by the counter 97. Specifically, when the toner remaining amount is less than 50%, the method of detecting the remaining amount of toner is switched from the second remaining amount sensor 550 to pixel counting. Here, when switching, the value of the light-blocking time count by the second remaining amount sensor 550 and the value corresponding to the light-blocking time count in the pixel count are made to be not discontinuous. In other words, the pixel count takes over the value of the light-blocking time count by the second remaining amount sensor 550 up to 50% of the toner remaining amount. A method of converting the value of the counter 97 to the light-blocking time count will be described below with reference to FIG. 13.

[0079] (Counter 97 conversion method) If the time taken for the stirring member 34 to make one rotation is, for example, one second, when the remaining toner amount in the developing container 32 is as high as 80%, the toner being stirred blocks light for 0.8 seconds out of one second. On the other hand, when the remaining toner amount in the developing container 32 is as low as 10%, the toner being stirred blocks light for only 0.1 seconds out of one second. In this way, during the one second it takes the stirring member 34 to make one rotation, the light blocking time changes depending on the amount of remaining toner being stirred. The second remaining amount sensor 550 calculates the remaining amount of toner using this light blocking time.

[0080] 13(a) and (b) are graphs in which the vertical axis indicates the light blocking time counted at a predetermined sampling interval when the toner remaining amount sensor 500 blocks light during one rotation of the stirring member 34. The sampling interval is determined by the operating speed of the CPU 91, etc. The vertical axis indicates the counted light blocking time during a certain period of time, and the horizontal axis indicates the remaining toner amount (%) in the developing container 32.

[0081] For example, the control unit 90 counts one second for one rotation of the stirring member 34 as 100 counts, judges whether light is blocked or transmitted every 0.01 seconds, and if light is blocked, adds one count to the counter that counts the light blocking time, and accumulates the counts. If the light blocking time is 80 counts out of the 100 counts for one rotation of the stirring member 34, the remaining toner amount is determined to be 80%, and if the light blocking time is 10 counts, the remaining toner amount is determined to be 10%.

[0082] On the other hand, in the counter 97 used for pixel counting, the control unit 90 monitors the laser emission state (on or off) for each unit time during image formation of one page, and adds 1 to the count when it is on, and adds 0 when it is off. In this way, the control unit 90 determines the cumulative sum of the laser emission state.

[0083] For example, when the value of counter 97, which indicates the laser illumination state per unit time during one page image formation period, reaches 10,000, control unit 90 estimates that only 1% of the toner has been consumed. Control unit 90 estimates the remaining toner amount by subtracting 1% of the consumed toner amount from the remaining toner amount before counting began. A count of 10,000 by counter 97 corresponds to 1% of the toner amount, and corresponds to 1 count of the light blocking time count of remaining toner amount sensor 500 described above.

[0084] In this way, the value of the pixel count counter 97 can be converted into the light blocking time count value of the toner remaining sensor 500. In FIG. 13(a), the value of the pixel count counter 97 converted into the light blocking time count and plotted is shown by a dashed line. The expression "take over" mentioned above indicates that the graph of the second remaining sensor 550 shown by the solid line in FIG. 13(a) and the graph of the pixel count shown by the dashed line are smoothly connected at 50% toner remaining. The graph of the second remaining sensor 550 is shown by the solid line L550, the graph of the first remaining sensor 510 by the solid line L510, and the graph of the pixel count by the dashed line Lp. The pixel count after this conversion is referred to as "light blocking time count of pixel count" as in the case of the toner remaining sensor 500.

[0085] Next, when the remaining toner amount is less than 50%, by obtaining the difference Δα between the light-blocking time count by pixel count and the light-blocking time count by first remaining amount sensor 510, it is possible to estimate the individual difference between second remaining amount sensor 550 and first remaining amount sensor 510. This is because, as shown in FIG. 13(a), the light-blocking time count by pixel count is also the light-blocking time count by second remaining amount sensor 550.

[0086] The individual differences between second remaining amount sensor 550 and first remaining amount sensor 510 in the first embodiment are caused by individual variations in light emitting element 510a, light receiving element 510b, and electrical components in light emitting element 550a and light receiving element 550b. Therefore, when the remaining toner amount is less than 50%, the remaining toner amount detected by pixel counting by counter 97 is notified to the user, while the remaining toner amount is also detected by first remaining amount sensor 510.

[0087] Returning to the description of the flowchart of FIG. 14, in S108, the control unit 90 performs the toner remaining amount detection by the first remaining amount sensor 510. The control unit 90 also continues to perform the toner remaining amount detection by the second remaining amount sensor 550. This is because some users may replenish toner early when the toner remaining amount is less than 50%, and the toner remaining amount detection by the second remaining amount sensor 550 is more accurate. In addition, the image forming apparatus 1 of this embodiment allows the user to replenish toner all at once at any time. The detection results of the toner remaining amount by the first remaining amount sensor 510 and the second remaining amount sensor 550 are not notified to the user. In S109, the control unit 90 stores the difference Δα between the light blocking time count of the pixel count and the light blocking time count of the first remaining amount sensor 510 in the ROM 93. Here, since the difference Δα differs depending on the toner remaining amount, while the toner remaining amount detection by the pixel count is being performed, the control unit 90 sequentially acquires the difference Δα, that is, acquires a plurality of differences Δα.

[0088] In S110, the control unit 90 determines whether the remaining toner amount is less than 50% based on the detection result of the second remaining toner amount sensor 550. If the control unit 90 determines in S110 that the remaining toner amount is not less than 50%, it determines that the user has replenished toner, and proceeds to S121. If the control unit 90 determines in S110 that the remaining toner amount is less than 50%, it proceeds to S111.

[0089] In S111, the control unit 90 determines whether the remaining toner amount is 10% or less based on the detection result of the remaining toner amount by pixel count. If the control unit 90 determines in S111 that the remaining toner amount is greater than 10%, the process returns to S106. In this case, the control unit 90 continues to notify the user of the remaining toner amount detected by pixel count. Also, the control unit 90 continues to store in ROM 93 the difference Δα between the light blocking time count of the pixel count and the light blocking time count of the first remaining toner amount sensor 510 in S109. As a result, multiple differences Δα are accumulated in ROM 93.

[0090] If the control unit 90 determines in S111 that the remaining toner amount is 10% or less, it advances the process to S120. In S112, the control unit 90 stops the printing operation. After the printing operation is stopped, the control unit 90 instructs the user to perform a replenishment operation. The means for instructing the user to perform the operation is the display unit 301 of the operation unit 300, but may also be a personal computer connected to the image forming apparatus 1. After the toner is replenished, the control unit 90 returns to the process of S102 and restarts printing. It should be noted that the control unit 90 may proceed to the process of S121.

[0091] At S121, the control unit 90 determines that the user has replenished toner, and again detects the remaining toner amount with the second remaining amount sensor 550. At S122, the control unit 90 notifies the user of the detection result of the remaining toner amount by the second remaining amount sensor 550. At S123, the control unit 90 determines whether the detection result of the remaining toner amount by the second remaining amount sensor 550 is less than 50%. If the control unit 90 determines in S123 that the remaining toner amount is not less than 50%, the process returns to S121, and the control unit 90 continues to notify the user of the detection result of the second remaining amount sensor 550.

[0092] If the control unit 90 determines in S123 that the remaining toner amount is less than 50%, the process proceeds to S124. In S124, the control unit 90 starts detecting the remaining toner amount using the first remaining amount sensor 510. That is, at this timing, the control unit 90 switches the means used to notify the remaining toner amount from the second remaining amount sensor 550 to the first remaining amount sensor 510. Note that even after switching to the first remaining amount sensor 510, the control unit 90 continues to monitor the remaining toner amount using the second remaining amount sensor 550, although it does not use the second remaining amount sensor 550 to notify the user.

[0093] In S125, the control unit 90 reads from the ROM 93 a plurality of differences Δα between the light-blocking time count of the pixel count stored in the ROM 93 in S109 and the light-blocking time count of the first remaining amount sensor 510, and calculates an average value Δα1 (correction value) of these differences. The control unit 90 corrects the light-blocking time count of the first remaining amount sensor 510 by subtracting the average difference Δα1 from the light-blocking time count of the first remaining amount sensor 510. As a result, the solid line L510 of the first remaining amount sensor 510 shown in FIG. 13(a) is subtracted by Δα1, and is corrected to the broken line Lp of the pixel count. In S126, the control unit 90 notifies the user of the remaining toner amount estimated using the corrected light-blocking time count of the first remaining amount sensor 510.

[0094] In S127, the control unit 90 determines whether the remaining toner amount detected by the second remaining toner amount sensor 550 is less than 50%. If the control unit 90 determines in S127 that the remaining toner amount is less than 50%, the process proceeds to S128. In S128, the control unit 90 determines whether the remaining toner amount detected by the first remaining toner amount sensor 510 is 10% or less. If the control unit 90 determines in S128 that the remaining toner amount is more than 10%, the process returns to S124, and the control unit 90 continues to notify the user of the corrected detection result of the remaining toner amount detected by the first remaining toner amount sensor 510.

[0095] In this way, by using the corrected detection result of the first remaining amount sensor 510, as shown in Fig. 13(b), it is possible to provide continuity in switching between the second remaining amount sensor 550 and the first remaining amount sensor 510, and the user can be notified of the remaining toner amount without feeling uncomfortable. In Fig. 13(b), the light blocking time count of the first remaining amount sensor 510 before correction is shown by a dashed line L510, and the light blocking time count of the first remaining amount sensor 510 after correction with the difference Δα1 is shown by a solid line L510'. Furthermore, the first remaining amount sensor 510 can detect a low toner remaining amount of about 10% with greater accuracy than remaining amount detection by pixel counting, and therefore can correctly notify the user of the low remaining toner amount in the developing container 32.

[0096] Returning to the description of the flowchart in Fig. 14, if the control unit 90 determines in S128 that the remaining toner amount is 10% or less, the process proceeds to S130. In S130, the control unit 90 stops the print operation until the user replenishes toner. Note that, if the user replenishes toner, the control unit 90 starts printing. Here, the control unit 90 may resume the process from S121 so that the correction is performed, rather than starting printing in S102 before the correction of the first remaining amount sensor 510.

[0097] As described above, the control unit 90 detects the remaining toner amount by the second remaining amount sensor 550, and when the remaining toner amount becomes less than 50%, it switches from detecting the remaining toner amount by the second remaining amount sensor 550 to detecting the remaining toner amount by pixel counting. In the section where the remaining toner amount is less than 50%, the control unit 90 continues to store in the ROM 93 the difference between the detection result of the pixel count and the first remaining amount sensor 550. Toner is replenished and the remaining toner amount is detected again by the second remaining amount sensor 550. Next, when the remaining toner amount becomes less than 50%, the control unit 90 switches from detecting the remaining toner amount by the second remaining amount sensor 550 to detecting the remaining toner amount by the first remaining amount sensor 510. The control unit 90 changes the detection result of the first remaining amount sensor 510 based on the difference between the detection result of the pixel count and the detection result of the first remaining amount sensor 510, after the user performs the toner replenishment operation and the second remaining amount sensor 550 detects that the remaining toner amount has increased.

[0098] (Modification) In the above example, as shown in FIG. 13B, the light blocking time count of the first remaining amount sensor 510 is corrected by subtracting the difference Δα1 from the light blocking time count of the first remaining amount sensor 510. However, the second remaining amount sensor 550 may be corrected. For example, the light blocking time count of the second remaining amount sensor 550 may be corrected by adding the difference Δα1 to the light blocking time count of the second remaining amount sensor 550. The timing for correcting the result of the second remaining amount sensor 550 may be the timing when the toner remaining amount of the second remaining amount sensor 550 increases to 50% or more, that is, the timing when the determination in S110 becomes NO. In other words, the second remaining amount sensor 550 may be corrected when the user performs toner replenishment. In the above example, multiple differences are obtained when toner has not been replenished even once (first round), and the detection result of first remaining amount sensor 510 is corrected using the differences after toner has been replenished once (second round or later), but this is not limited to the above. For example, multiple differences may be obtained even in the second round or later, or toner remaining amount detection may be switched from pixel count to first remaining amount sensor 510 in the middle of the first round if a sufficient number of differences can be obtained.

[0099] As shown in the first embodiment, by detecting the amount of remaining toner by pixel counting, it is possible to prevent discontinuous states caused by individual differences between sensors while using multiple sensors such as the second remaining amount sensor and the first remaining amount sensor shown in Fig. 13(b), and to notify the user of the accurate amount of remaining toner.

[0100] As described above, according to the first embodiment, when multiple toner remaining sensors are switched to notify the remaining toner amount, even if there are individual differences between the toner remaining sensors, it is possible to prevent the remaining toner amount notified to the user from becoming discontinuous when the toner remaining sensor is switched. EXAMPLES

[0101] In the first embodiment, as shown in FIG. 14, when the remaining toner amount falls below 50%, the result of detection of the remaining toner amount using pixel counting is notified to the user (S107). However, as described above, pixel counting is a method of estimating the amount of toner consumed based on the count of the ON time during which laser light is irradiated from the scanner unit 11. With pixel counting, the smaller the remaining toner amount is, the more error accumulates with respect to the actual remaining toner amount, and the lower the accuracy becomes. Therefore, in the second embodiment, a configuration is described in which, after the printer main body 100 is initially installed, the first remaining toner amount sensor 510 is used without using pixel counting.

[0102] [Control of remaining amount detection in embodiment 2] Only the control configuration of remaining amount detection different from that of the first embodiment will be specifically described with reference to Figs. 15(a), (b) and 16. Fig. 15(a) shows the difference Δγ0 between the light blocking time counts of the first remaining amount sensor 510 and the second remaining amount sensor 550 when the toner remaining amount is 50%. In the flowchart showing the control of the toner remaining amount detection in Fig. 16, a correction is performed based on the difference Δγ0 between the light blocking time counts of the first remaining amount sensor 510 and the second remaining amount sensor 550, and a means for changing the state of Fig. 15(a) to the state of Fig. 15(b) is described. In Fig. 15(b), the dashed line L510 shows the light blocking time count of the first remaining amount sensor 510 before correction, and the solid line L510' shows the light blocking time count of the first remaining amount sensor 510 after correction.

[0103] [correction] In the flowchart of Fig. 16, the processes from S201 to S205 are the same as the processes from S101 to S105 in Fig. 14, and therefore the description will be omitted. If the remaining amount of toner is less than 50% (YES in S205), in S206 the control unit 90 detects the remaining amount of toner by the first remaining amount sensor 510. In S207, the control unit 90 calculates the difference Δγ0 between the light blocking time counts of the second remaining amount sensor 550 and the first remaining amount sensor 510 when the remaining amount of toner is 50%, and stores the difference in the light blocking time counts in the ROM 93.

[0104] In S208, the control unit 90 starts detecting the remaining toner amount by the first remaining toner sensor 510. In S209, the control unit 90 corrects the light-blocking time count of the first remaining toner sensor 510 with the difference Δγ0 of S207. Specifically, the control unit 90 subtracts the difference Δγ0 from the light-blocking time count of the first remaining toner sensor 510. As a result, the light-blocking time count of the first remaining toner sensor 510 is corrected to the light-blocking time count of the second remaining toner sensor 550. In S210, the control unit 90 notifies the user of the corrected detection result of the remaining toner amount by the first remaining toner sensor 510.

[0105] In S211, the control unit 90 determines whether the remaining toner amount estimated by the corrected first remaining amount sensor 510 is 50% or less. If the control unit 90 determines in S211 that the remaining toner amount is greater than 50%, it determines that the user has performed toner replenishment, and returns the process to S203, where the control unit 90 again detects the remaining toner amount using the second remaining amount sensor 550.

[0106] If the control unit 90 determines in S211 that the amount of remaining toner measured by the first remaining amount sensor 510 is 50% or less, the process proceeds to S212. In S212, the control unit 90 determines whether the amount of remaining toner measured by the first remaining amount sensor 510 after correction is 10% or less. If the control unit 90 determines in S212 that the amount of remaining toner is more than 10%, the process returns to S208, and the detection of the amount of remaining toner by the first remaining amount sensor 510 is repeated.

[0107] If the control unit 90 determines in S212 that the remaining toner amount is 10% or less, it proceeds to process 220. In S220, the control unit 90 stops the print operation until the user replenishes toner. If the user replenishes toner, the process resumes from S202 and printing begins. Through this control, the difference Δγ0 between the light blocking time counts of the first remaining amount sensor 510 and the second remaining amount sensor 550 changes from the state shown in FIG. 15(a) before correction to the state shown in FIG. 15(b).

[0108] In the second embodiment, the individual difference between the first remaining amount sensor 510 and the second remaining amount sensor 550, in other words the difference Δγ0, is used to correct, and the first remaining amount sensor 510 is used from the first cycle when the user initially installs the printer main body 100. This makes it possible to accurately detect the state of 10% remaining toner as shown in Fig. 12(c). Note that, as in the modified example of the first embodiment, the light blocking time count of the second remaining amount sensor 550 may be corrected.

[0109] [Application example of Example 1 and Example 2] When the detection accuracy of either the first remaining amount sensor 510 or the second remaining amount sensor 550 is low when the toner remaining amount is 50%, i.e., in the state of Fig. 17(a), using the control of embodiment 2 results in the state of Fig. 17(b). In other words, because the detection accuracy of either the first remaining amount sensor 510 or the second remaining amount sensor 550 when the toner remaining amount is 50% is low, the difference Δγ0 used for correction is significantly off, and the first remaining amount sensor 510 is unable to correctly detect a toner remaining amount of 10%.

[0110] Therefore, it is preferable to apply the second embodiment to a configuration in which the continuous detection accuracy of the first remaining amount sensor 510 and the second remaining amount sensor 550 can be maintained, that is, a configuration in which the first remaining amount sensor 510 and the second remaining amount sensor 550 can detect to a certain extent correctly when the toner remaining amount is 50%. For example, it is effective in a configuration in which the first remaining amount sensor 510 and the second remaining amount sensor 550 are arranged close to each other. Conversely, for a configuration in which the first remaining amount sensor 510 and the second remaining amount sensor 550 cannot detect correctly when the toner remaining amount is 50%, for example, a configuration in which the first remaining amount sensor 510 and the second remaining amount sensor 550 are arranged far apart, the first embodiment using pixel counting is preferable.

[0111] Furthermore, even if the accuracy of toner remaining sensor 500 is low when the toner remaining amount is 50%, pixel counting may be used only for a portion of the toner remaining amount at 50%. For example, pixel counting may be used when the toner remaining amount is between 60% and 40% as shown in Fig. 17, and when the toner remaining amount is 40%, correction may be made using the difference with the light blocking time count of first remaining sensor 510, and the corrected first remaining sensor 510 may be used.

[0112] Furthermore, the toner remaining amount sensor 500 described in the first and second embodiments may be configured to use three or more toner remaining amount sensors in addition to the first remaining amount sensor 510 and the second remaining amount sensor 550 .

[0113] As described above, according to the second embodiment, when multiple toner remaining sensors are switched to notify the remaining toner amount, even if there are individual differences between the toner remaining sensors, it is possible to prevent the remaining toner amount notified to the user from becoming discontinuous when the toner remaining sensor is switched.

[0114] The disclosure of this embodiment includes the following configuration. (Configuration 1) A photosensitive drum; an exposure unit that causes a light source to emit light based on image information to form an electrostatic latent image on the photosensitive drum; a developer container having a supply port through which toner is supplied from the outside of the image forming apparatus and containing toner; a developing roller for developing the electrostatic latent image with the toner contained in the developing container to form a toner image; a first detection means for outputting information corresponding to the remaining amount of toner when the remaining amount of toner in the developing container is less than a predetermined amount; a second detection unit that outputs information corresponding to the amount of toner remaining in the developing container when the amount of toner remaining in the developing container is equal to or greater than the predetermined amount; a counting means for estimating a toner consumption amount based on a value obtained by counting the light emission state of the light source for each pixel based on the image information; an image forming apparatus capable of replenishment of toner in one go to the developing container through the replenishing port, a control means for controlling to notify the toner remaining amount based on the detection result by the second detection means up to the predetermined amount, and to notify the toner remaining amount based on the estimation result by the counting means or the detection result by the first detection means when the toner remaining amount is less than the predetermined amount, The control means when the remaining amount of toner falls below the predetermined amount, notifying the remaining amount of toner based on the amount of toner consumption estimated by the counting means, and acquiring a plurality of differences between the remaining amount of toner measured by the counting means and the remaining amount of toner measured by the first detection means; an image forming apparatus which, when toner is replenished to the developing container through the supply port after obtaining a plurality of the differences and the remaining amount of toner detected by the second detection means again falls below the predetermined amount, notifies the remaining amount of toner detected by the first detection means corrected by a correction value based on the plurality of the differences. (Configuration 2) The image forming apparatus according to claim 1, wherein the control means sets an average value of a plurality of the differences as the correction value. (Configuration 3) A storage unit for storing information on the difference, The above-mentioned image forming apparatus is characterized in that the control means continues to store the difference in the memory unit from the time when the amount of toner contained in the developing container decreases to the predetermined amount and the counting means switches to detecting the remaining toner amount, until the time when a user performs a toner replenishment operation and the second detection means detects that the remaining toner amount has increased above the predetermined amount. (Configuration 4) The above-mentioned image forming device, characterized in that the control means corrects the detection result of the remaining toner amount by the second detection means based on the difference between the detection result of the remaining toner amount by the counting means and the detection result of the remaining toner amount by the first detection means. (Configuration 5) a rotatable image carrier carrying an electrostatic latent image; an exposure unit having a light source for emitting a laser beam and for forming the electrostatic latent image by the laser beam; a developing container having a supply port through which the toner is supplied and containing the toner; a toner carrier that develops the electrostatic latent image with the toner contained in the developing container to form a toner image; a first detection means for detecting the amount of toner contained in the developing container when the amount of toner contained in the developing container is less than a predetermined amount and outputting information corresponding to the amount of toner; a second detection means for detecting the amount of toner contained in the developing container more accurately than the first detection means when the amount of toner contained in the developing container is equal to or greater than the predetermined amount, and outputting information corresponding to the amount of toner; and allowing a user to replenish toner to the developing container at any time, a control means for controlling to notify the toner remaining amount based on the detection result by the second detection means up to the predetermined amount, and to notify the toner remaining amount based on the detection result by the first detection means when the toner remaining amount is less than the predetermined amount, The image forming apparatus is characterized in that, when the remaining amount of toner falls below the predetermined amount, the control means obtains the difference between the remaining amount of toner detected by the second detection means and the remaining amount of toner detected by the first detection means, and notifies the remaining amount of toner detected by the first detection means corrected by the difference. [Explanation of symbols]

[0115] 11 Scanner unit 21 Photosensitive drum 32 Developer container 90 Control section 97 Counter 510 1st remaining amount sensor 550 Second remaining amount sensor

Claims

1. A photosensitive drum; an exposure unit that causes a light source to emit light based on image information to form an electrostatic latent image on the photosensitive drum; a developer container having a supply port through which toner is supplied from the outside of the image forming apparatus and containing toner; a developing roller for developing the electrostatic latent image with the toner contained in the developing container to form a toner image; a first detection unit that outputs information corresponding to the remaining amount of toner when the remaining amount of toner in the developing container is less than a predetermined amount; a second detection unit that outputs information corresponding to the amount of toner remaining in the developing container when the amount of toner remaining in the developing container is equal to or greater than the predetermined amount; a counting means for estimating a toner consumption amount based on a value obtained by counting the light emission state of the light source for each pixel based on the image information; an image forming apparatus capable of replenishment of toner in one go to the developing container through the replenishing port, a control means for controlling to notify the toner remaining amount based on the detection result by the second detection means up to the predetermined amount, and to notify the toner remaining amount based on the estimation result by the counting means or the detection result by the first detection means when the toner remaining amount is less than the predetermined amount, The control means when the remaining amount of toner falls below the predetermined amount, a remaining amount of toner based on the amount of toner consumption estimated by the counting means is notified, and a plurality of differences between the remaining amount of toner measured by the counting means and the remaining amount of toner measured by the first detection means are obtained; an image forming apparatus which, when toner is replenished to the developing container through the supply port after obtaining a plurality of the differences, and the amount of toner remaining as detected by the second detection means again falls below the predetermined amount, notifies the user of the amount of toner remaining corrected by a correction value based on the plurality of the differences.

2. 2. The image forming apparatus according to claim 1, wherein the control unit determines the correction value as an average value of a plurality of the differences.

3. A storage unit for storing information on the difference, The image forming apparatus according to claim 1, characterized in that the control means continues to store the difference in the memory unit from the time when the amount of toner contained in the developing container decreases to the predetermined amount and the counting means switches to detect the remaining toner amount, until the time when a user performs a toner replenishment operation and the second detection means detects that the remaining toner amount has increased above the predetermined amount.

4. 2. The image forming apparatus according to claim 1, wherein the control means corrects the detection result of the remaining toner amount by the second detection means based on a difference between the detection result of the remaining toner amount by the counting means and the detection result of the remaining toner amount by the first detection means.

5. A photosensitive drum; an exposure unit that causes a light source to emit light based on image information to form an electrostatic latent image on the photosensitive drum; a developer container having a supply port through which toner is supplied from the outside of the image forming apparatus and containing toner; a developing roller for developing the electrostatic latent image with the toner contained in the developing container to form a toner image; a first detection unit that outputs information corresponding to the remaining amount of toner when the remaining amount of toner in the developing container is less than a predetermined amount; a second detection unit that outputs information corresponding to the amount of toner remaining in the developing container when the amount of toner remaining in the developing container is equal to or greater than the predetermined amount; an image forming apparatus capable of replenishment of toner in one go to the developing container through the replenishing port, a control means for controlling to notify the toner remaining amount based on the detection result by the second detection means up to the predetermined amount, and to notify the toner remaining amount based on the detection result by the first detection means when the toner remaining amount is less than the predetermined amount, The image forming apparatus is characterized in that, when the remaining amount of toner falls below the predetermined amount, the control means obtains the difference between the remaining amount of toner detected by the second detection means and the remaining amount of toner detected by the first detection means, and notifies the remaining amount of toner detected by the first detection means corrected by the difference.

Images