JP5246153B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a FAX, or a copier that forms characters and images on a recording medium such as paper using toner, ink, or the like.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus is known that includes a toner remaining amount detecting unit that detects a remaining amount of toner in a toner storage chamber in a cartridge.

  The toner remaining amount detecting means includes a light emitting means for emitting light passing through the accommodation chamber and a light receiving means for receiving light from the light emitting means, and a light reception ratio (transmittance) calculated from a detection result from the light receiving means. Is used to detect the remaining amount of toner in the storage chamber.

  However, in such an image forming apparatus, if the distribution of toner in the storage chamber is greatly different or if a part of the toner floats in the storage chamber, the light reception ratio is greatly different and the accuracy of the remaining amount detection can be improved. difficult.

On the other hand, an electrophotographic image forming apparatus is also known that includes a toner consumption estimation unit that detects a toner consumption amount in a cartridge by a control unit counting the number of dots of image data. (Patent Document 1)
In this image forming apparatus, the dot count value is recorded in a control unit in the image forming apparatus, and the toner consumption amount is calculated by multiplying the toner amount per dot recorded in the control unit by the dot count value. ing.

  When the toner consumption reaches a predetermined value, an empty indicating that the cartridge replacement time is near is displayed. The user can know when to replace the cartridge by displaying this empty.

  Further, when the user replaces a new cartridge, the control unit detects that a new cartridge is loaded, resets the stored dot count value, and calculates the toner consumption amount of the new cartridge.

  However, in such an image forming apparatus, the actual toner remaining amount is not detected, but the toner consumption amount is calculated by assuming the toner amount per dot in advance. There is a problem that when printing is performed with a different toner amount from the assumed toner amount, the difference between the calculated toner consumption amount and the actual toner consumption amount becomes large.

  For example, as in Patent Document 2, an image forming apparatus that uses an optical toner remaining amount detection unit and a toner consumption estimation unit using a dot count method is also known.

  In this image forming apparatus, when the remaining toner amount is high by the toner remaining amount detecting means, the detection result by the toner consumption estimating means is adopted, and when the remaining toner amount is low, the detection result by the remaining toner amount detecting means is adopted. Thus, the remaining toner information in the cartridge is sequentially displayed to the user.

JP 2004-205590 A JP 2004-139058 A

  However, in such an image forming apparatus, for example, a problem occurs when the cartridge is replaced with a cartridge that has been used in the past and has consumed some toner during use of the cartridge.

  In this case, since the loaded cartridge is not a new cartridge, the dot count value is not reset and the dot count value before replacement is stored in the image forming apparatus. Then, the image forming apparatus adds the number of dots thereafter to the dot count value of the cartridge before replacement, even though a cartridge that consumes less toner is loaded. As a result, the image forming apparatus instructs the user to replace the cartridge even though the toner remains sufficiently in the cartridge, and the user cannot accurately notify the user of the replacement time of the cartridge. Happens.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can notify a user of the replacement timing of a cartridge more accurately.

  In order to achieve this object, according to the first aspect of the present invention, in an image forming apparatus for forming an image on a recording medium via a developer, a cartridge having a storage portion in which the developer is stored is mounted. On the cartridge mounting portion based on the integrated value of the number of dots of image information, and a developer remaining amount detecting means for detecting the remaining amount of developer in the cartridge mounted on the cartridge mounting portion. Developer usage amount estimation means for estimating the usage amount of the developer in the mounted cartridge, remaining amount information obtained based on the developer remaining amount detection means, and development obtained based on the developer usage amount estimation means Storage means for storing the usage amount information of the developer, remaining amount information of the developer stored in the storage means before the cartridge is pulled out from the cartridge mounting portion, and new information When the difference from the developer remaining amount information detected by the developer remaining amount detecting means after the cartridge is mounted in the cartridge mounting portion becomes a predetermined value or more, the developer after the cartridge is newly mounted And a control unit that corrects the usage amount information of the developer before the cartridge stored in the storage unit is pulled out based on the remaining amount information.

  According to a second aspect of the present invention, in the first aspect of the present invention, the developer remaining amount detecting means includes a light emitting element and a light receiving element, and light emitted from the light emitting element is contained in a storage portion of the cartridge. The remaining amount information of the developer in the cartridge is detected based on the transmittance that passes through the light receiving element and passes through the light receiving element, and the control unit newly adds the transmittance before the cartridge is pulled out from the cartridge mounting portion. The correction is performed when the difference from the transmittance after the cartridge is mounted on the cartridge mounting portion is 5% or more.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the cartridge mounted on the cartridge mounting portion is provided with an agitator for stirring the developer, The developer remaining amount detecting means detects the remaining amount of developer in the mounted cartridge after the agitator rotates a predetermined number of times.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, the cartridge mounting portion includes any one of at least two types of cartridges having different developer accommodating amounts. A cartridge discriminating unit for discriminating whether or not a cartridge is mounted is provided, and the storage unit is provided with a second storage unit for storing the maximum usable amount of developer of the two types of cartridges, and the control unit is provided with the control unit. Further, the present invention is characterized in that rewriting means is provided for rewriting the maximum usable amount of developer before cartridge replacement into the maximum usable amount of developer of the cartridge determined by the cartridge determining means.

  According to the first aspect of the present invention, the controller has a predetermined difference between the remaining amount information of the developer before the cartridge is pulled out and the remaining amount information of the developer after the cartridge is mounted. In this case, the developer usage amount information stored in the storage unit is corrected based on the remaining amount information of the developer after the cartridge is mounted. In this way, the control unit corrects the developer usage amount information before the cartridge stored in the storage unit is pulled out, so even if a non-new cartridge is mounted, the control unit is based on the cartridge usage amount information. Thus, it is possible to accurately notify the user of the replacement time of the cartridge.

  According to the second aspect of the present invention, the controller corrects when the difference between the transmittance before the cartridge is pulled out and the transmittance after the cartridge is mounted is 5% or more. The difference between the cartridge before and after the cartridge is pulled out can be detected with high accuracy, and the user can be notified of the replacement timing of the cartridge more accurately.

  According to the third aspect of the present invention, the developer remaining amount detecting means detects the remaining amount of developer in the cartridge after the agitator has rotated a predetermined number of times, so that the developer is biased in the cartridge. Even if it is contained, the agitator agitates the developer to eliminate the unevenness. Thereby, the developer remaining amount detecting means can accurately detect the remaining amount of the developer.

  According to the invention described in claim 4, the rewriting means rewrites the maximum usable amount of developer before the cartridge replacement with the maximum usable amount of developer of the cartridge determined by the cartridge determining means. In addition, even when a cartridge with a different developer capacity is mounted, the user can be notified of the replacement time corresponding to the mounted cartridge.

Side sectional view showing schematic configuration of laser printer Side sectional view showing the laser printer with the process cartridge removed Block diagram showing the configuration of the control device A perspective view showing a developing cartridge and a photosensitive cartridge Flowchart explaining processing after printing on one sheet of paper is completed A flowchart for explaining processing for correcting the accumulated dot count value stored in the storage unit when a process cartridge having a developing cartridge that is not new is mounted. Block diagram showing the configuration of the control device A series of processes for correcting the cumulative dot count value and the maximum dot count value stored in the storage unit when the process cartridge is mounted in an image forming apparatus using two types of developing cartridges having different toner storage amounts will be described. flowchart

[Overall structure of laser printer]
FIG. 1 is a side sectional view showing a schematic configuration of a laser printer 1 as an example of an image forming apparatus of the present embodiment.

  As shown in FIG. 1, the laser printer 1 includes a main body housing 2, and in the main body housing 2, a paper feeding unit 4 that supplies paper to the image forming unit 5, and an image on the fed paper. The image forming unit 5 to be formed, the paper discharge unit 6 that discharges the paper on which the image is formed, and a control device 13 (see FIG. 3) that controls the operation of the laser printer 1 are further provided.

  In the following description, unless otherwise specified, the vertical direction shown in FIG. 1 is up and down, the right side in FIG. 1 is front, the left side is rear, the back side of the paper is right, and the front side of the paper is left. Indicates. The direction here is defined based on the direction seen from the person standing in front of the laser printer 1.

  As shown in FIG. 2, a process cartridge mounting portion 20 as an example of a cartridge mounting portion is formed in the main body housing 2, and a cover 21 that can open and close the process cartridge mounting portion 20 is provided.

  The cover 21 is rotatably supported by a cover shaft (not shown) provided at the lower end thereof. When the cover 21 is closed (closed state), the process cartridge mounting portion 20 is closed by the cover 21 as shown in FIG. When the cover 21 is opened (open state), as shown in FIG. 2, the process cartridge mounting portion 20 is opened, and the process cartridge 7 described later can be attached and detached from the process cartridge mounting portion 20.

(1) Paper Feed Unit The paper feed unit 4 includes a paper feed tray 41 for storing paper, a paper feed roller 42, a paper feed pad 43, and a registration roller 44 below the main body housing 2.

  In the paper feed unit 4 configured in this way, the paper is separated one by one from the paper feed tray 41 and sent to the image forming unit 5.

(2) Image Forming Unit The image forming unit 5 includes an exposure unit 51 that forms an electrostatic latent image by applying a laser beam to the surface of the photosensitive drum 73, a process cartridge 7 that transfers a toner image to a sheet, and a sheet A fixing unit 9 for thermally fixing the upper toner image is provided.

(2-1) Exposure Unit The exposure unit 51 is provided in the upper part of the main body housing 2 and includes a laser light emitting unit (not shown), a polygon mirror 51a, a lens 51b, and a reflecting mirror 51c.

  In the exposure unit 51 configured as described above, laser light emitted from the laser light source based on predetermined image data is scanned at high speed in the left-right direction by the polygon mirror 51a, and passes or reflects through the lens 51b and the reflecting mirror 51c. After that, the photosensitive drum 73 is irradiated.

(2-2) Process Cartridge The process cartridge 7 is disposed below the exposure unit 51 and above the sheet feeding unit 4 and is configured to be detachably attached to the main body housing 2. Yes. As shown in FIG. 4, the process cartridge 7 includes a photoconductor cartridge 71 constituting an outer frame, and a developing cartridge 8 that can be attached to and detached from the photoconductor cartridge 71.

  The photoconductor cartridge 71 includes a photoconductor cartridge frame 72. Within the photoconductor cartridge frame 72, a photoconductor drum 73 rotatably supported by the cartridge frame 72, and a charger 74 for charging the photoconductor drum 73, The image forming apparatus further includes a transfer roller 75 that transfers the toner image formed on the photosensitive drum 73 to a sheet.

  As shown in FIG. 4, transmissive windows 76 are formed on both side walls of the photosensitive cartridge frame 72 to transmit light emitted from a light emitting unit 10a of a toner remaining amount detecting unit 10 described later to a toner accommodating unit 84 described later. ing.

  The developing cartridge 8 includes a developing cartridge frame 81. The developing cartridge frame 81 accommodates a developing roller 82 rotatably supported by the developing cartridge frame 81, a supply roller 83, and toner as an example of a developer. And a toner storage portion 84 for performing the above operation.

  On both side walls of the developing cartridge frame 81, there are formed transmission windows 85 through which light emitted from the light emitting portion 10a of the toner remaining amount detecting portion described later is transmitted to the toner accommodating portion 84.

  As shown in FIG. 1, the toner storage portion 84 is provided with an agitator 86 for stirring the toner in the toner storage portion 84. The agitator 86 has a rotation shaft 87 that extends in the left-right direction in the toner storage portion 84 and is rotationally driven by a driving source (not shown), and a stirring plate 88 that protrudes in the radial direction from the rotation shaft 87. ing. The agitator 86 is configured to agitate the toner accommodated in the toner accommodating portion 84 by the agitating plate 88 that rotates together with the rotating shaft 87.

  In the process cartridge 7 configured as described above, the surface of the photosensitive drum 73 is uniformly charged by the charger 74, and the charged surface of the photosensitive drum 73 is exposed by scanning with laser light. As a result, the electrostatic latent image is formed on the surface of the photosensitive drum 73. Then, the toner supplied from the developing cartridge 8 is held on the exposed portion of the photosensitive drum 74, whereby a toner image is formed on the surface of the photosensitive drum 73.

(2-3) Fixing Unit The fixing unit 9 includes a heating roller 91 that is disposed on the rear side of the process cartridge 7 and is heated by a heat source, and a pressure roller 92 that is in pressure contact with the heating roller 91.

  In the fixing unit 9 configured as described above, the toner image on the paper is thermally fixed as the paper passes between the heating roller 91 and the pressure roller 92.

(3) Paper Discharge Unit The paper discharge unit 6 includes a paper discharge roller 61 for conveying the paper that has passed through the fixing unit 9 and a paper discharge tray 62 for accumulating the paper conveyed by the paper discharge roller 61. Yes.

In the paper discharge unit 6 configured as described above, the paper fixed by the fixing unit 6 is conveyed by the paper discharge roller 61 and discharged onto the paper discharge tray 62.
[Electrical configuration]
Next, the configuration of the control device 13 will be described with reference to FIG.

  As illustrated in FIG. 3, the control device 13 includes a control unit 13 a as an example of a control unit, and a storage unit 13 c as an example of a storage unit.

  The control unit 13a includes a CPU 13b, the image forming unit 5, a display unit 22 for displaying the time for replacement of the developing cartridge 8 to the user, a toner remaining amount detecting unit 10 as an example of a developer remaining amount detecting unit, A new product detection unit 12 that detects whether the process cartridge attachment / detachment detection unit 11 and the developing cartridge 8 are unused is electrically connected.

  The storage unit 13c includes a ROM 13d and a RAM 13e.

  The ROM 13d stores various control programs for controlling the laser printer 1, various settings, initial values, and the like. For example, the ROM 13d stores the amount of toner used per dot of the image data, the maximum dot count value from the unused state in the process cartridge 7 to the time when replacement is necessary (the maximum amount of developer that can be used), and the toner described later. A table of accumulated dot count values corresponding to the transmittance by the remaining amount detecting unit 10 is stored.

  The RAM 13e is used as a work area from which various control programs are read, or as a storage area for temporarily storing image data. For example, an accumulated dot count value accumulated based on the printed image data is stored.

  The CPU 13b controls each component of the laser printer 1 through the control unit 13a while storing the processing result in the RAM 13e according to the control program read from the ROM 13d. Specifically, the CPU 13b calculates the toner usage amount of the developing cartridge 8 based on the accumulated dot count value accumulated based on the image information to be printed stored in the RAM 13e. That is, the CPU 13a functions as a toner usage amount estimation unit as an example of a developer usage amount estimation unit.

(Toner remaining amount detection unit)
Next, the remaining toner amount detection unit 10 will be described with reference to FIG.

  The toner remaining amount detection unit 10 includes an optical sensor that includes a light emitting unit 10a and a light receiving unit 10b.

  The light emitting unit 10 a and the light receiving unit 10 b are provided in the main body housing 2 and are disposed so as to face each other through transmission windows 76 and 85 formed on both side walls of the developing cartridge frame 81 and the photosensitive cartridge frame 72. ing. The remaining amount detection light emitted from the light emitting unit 10a is received by the light receiving unit 10b through the transmission windows 76 and 85. The remaining toner amount detection unit 10 determines the remaining amount of toner in the toner storage unit 84 of the developing cartridge 8 based on the received light amount (transmittance) received by the light receiving unit 10b relative to the emitted light amount emitted from the light emitting unit 10a. Detected.

(Process cartridge attachment / detachment detector)
Next, the process cartridge attachment / detachment detection unit 11 that detects attachment / detachment of the process cartridge 7 will be described.

  The optical sensor including the light emitting unit 10 a and the light receiving unit 10 b described above also functions as the process cartridge attachment / detachment detection unit 11 that detects attachment / detachment of the process cartridge 7.

  Specifically, if the light emitted from the light emitting unit 10a and the light received by the light receiving unit 10b are substantially the same amount of light (transmittance 100%), it is determined that the process cartridge 7 is not attached to the main body housing 2. On the contrary, if the light emitted from the light emitting unit 10a and the light received by the light receiving unit 10b have different light amounts (transmittance less than 100%, for example, transmittance 50%, etc.), the process cartridge 7 is attached to the main body housing 2. Judge that it has been.

(New article detection part)
Next, the new article detection unit 12 will be described.

  The new article detection unit 12 detects whether or not the mounted developing cartridge 8 is new in order to determine whether or not to reset the accumulated dot count value stored in the storage unit 13c.

  A new article detection sensor (not shown) which is an example of a new article detection means is provided on the side wall of the main body casing 2. This new product detection sensor includes a detection member and an optical sensor, and determines whether or not the developing cartridge 8 mounted by turning on or off the new product detection sensor is a new product.

  Specifically, the new article detection sensor is in an OFF state before the process cartridge 7 is attached to the main body casing 2. When the process cartridge 7 having the new developing cartridge 8 is mounted on the main body housing 2, the detecting member is rotated by a driving gear (not shown) provided on the side wall of the developing cartridge 8 to turn on the new detecting sensor. Put it in a state. When the process cartridge 7 having the developing cartridge 8 that is not new is mounted, the drive gear does not rotate the detection member, and therefore the new detection sensor is in an OFF state.

[Operation of control unit]
FIG. 5 is a flowchart showing a processing procedure after printing on one sheet is completed.

  First, the accumulated dot count value b1 and the transmittance a1 before printing on a sheet are stored at a predetermined position in the RAM 13e of the storage unit 13c.

  When printing on one sheet is completed, in step S101 (hereinafter referred to as S101, the same applies to other steps), the cumulative dot count value b1 stored in a predetermined position in the RAM 13e is updated to the cumulative dot count value b2. To do.

  In step S102, the control unit 13a obtains the transmittance a2 from the toner remaining amount detecting unit 10, and in step S103, the control unit 13a updates the transmittance a1 stored at a predetermined position in the RAM 13e to the transmittance a2. The processing procedure after printing on a single sheet is completed.

  FIG. 6 is a flowchart showing a processing procedure for correcting the accumulated dot count value stored in the storage unit 13c when the process cartridge 7 having the developing cartridge 8 that is not new is mounted.

  When the new product detection unit 12 and the process cartridge attachment / detachment detection unit 11 detect that the process cartridge 7 having the developing cartridge 8 that is not a new product is mounted, the agitator 86 provided in the toner storage unit 84 rotates a predetermined number of times in S104. To do.

  Next, in S105, the toner remaining amount detection unit 10 detects the remaining amount of toner in the developing cartridge 8 that is not new, and the control unit 13a obtains the transmittance a3 by the toner remaining amount detection unit 10.

  In S106, the control unit 13a acquires the transmittance a2 of the developing cartridge 8 before the process cartridge 7 having the developing cartridge 8 that is not a new one stored in the predetermined position of the RAM 13e is mounted. The transmittance a2 of the developing cartridge before the process cartridge 7 having the developing cartridge 8 not attached is compared with the transmittance a3 of the developing cartridge 8 that is not new, and it is determined whether or not the difference is 5% or more. To do.

  When the difference between the transmittance a2 of the developing cartridge before the process cartridge 7 having the developing cartridge 8 which is not new and the transmittance a3 of the developing cartridge 8 which is not new is 5% or more (S107, Yes) In S108, the control unit 13a uses the accumulated dot count value b2 stored in the RAM 13e as the accumulated dot count value b2 based on the table of accumulated dot counter values based on the transmittance stored in the ROM 13d. The correction is made to the count value b3, the accumulated dot count value b3 is stored in the RAM 13e, and the processing procedure for correcting the accumulated dot count value stored in the storage unit 13c when a developing cartridge 8 that is not a new product is mounted is completed. To do.

  On the other hand, when the difference between the transmittance a2 of the developing cartridge 8 before the process cartridge 7 having the developing cartridge 8 which is not new is mounted and the transmittance a3 after the detection of the process cartridge attachment / detachment is less than 5% (S107, No) The controller 13a does not correct the accumulated dot count value b2 stored in the RAM 13e, but corrects the accumulated dot count value stored in the storage unit 13c when a non-new developing cartridge 8 is mounted. The processing procedure ends.

  The effects of the laser printer 1 configured as described above will be described.

  In the laser printer 1 of the present embodiment, the control unit 13a determines the difference between the transmittance a2 of the developing cartridge 8 and the transmittance a3 of the developing cartridge 8 that is not new before the process cartridge having the developing cartridge 8 that is not new is mounted. Is different from the predetermined value, the accumulated dot count value b2 stored in the RAM 13e is corrected to the accumulated dot count value b3 corresponding to the transmittance a3 of the development cartridge 8 that is not new. Even when 8 is mounted, it is possible to accurately notify the user of the replacement timing of the developing cartridge 8 based on the usage amount of the developing cartridge 8.

  Further, the control unit 13a corrects when the difference between the transmittance a2 of the developing cartridge 8 and the transmittance a3 of the developing cartridge 8 which is not new is 5% before the process cartridge having the developing cartridge 8 which is not new is mounted. Therefore, by accurately detecting the difference between the developing cartridge 8 before and after the process cartridge 7 is mounted, the user can be more accurately informed of the replacement timing of the developing cartridge 8.

  When the removal of the process cartridge 7 is detected, the toner remaining amount detection unit 10 detects the remaining amount of toner in the toner storage unit 84 after the agitator 86 rotates a predetermined number of times. When the toner is biased, the agitator 86 agitates the toner to eliminate the bias. Thereby, the toner remaining amount detection unit 10 can accurately detect the remaining amount of toner.

<Embodiment 2>
Next, Embodiment 2 will be described.

  In the second embodiment, only differences from the first embodiment will be described in detail, and the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  The photosensitive cartridge 71 has a configuration in which two types of the first developing cartridge and the second developing cartridge having a larger amount of toner than the first developing cartridge can be attached and detached. The first developing cartridge and the second developing cartridge are different in the configuration of a drive gear for driving a developing cartridge discrimination sensor described later, and the basic configuration is the same.

  The toner accommodating portion 84 of the unused second developing cartridge is filled with a larger amount of toner than that of the unused first developing cartridge. That is, the maximum dot count value of the second developing cartridge is larger than that of the first developing cartridge.

[Electrical configuration]
As shown in FIG. 7, a developing cartridge determination unit 15 as an example of the cartridge determination unit 15 is electrically connected to the control unit 13a. Moreover, the control part 13b has the rewriting part 16 as an example of the rewriting means mentioned later.

  The storage unit 13c described in the first embodiment further includes a ROM 13d and a RAM 13e as an example of a second storage unit. The ROM 13d further includes the maximum dot count value D1 of the first developing cartridge and the second developing unit. The maximum dot count value D2 of the cartridge is stored.

(Developing cartridge discrimination unit)
Next, the developing cartridge determination unit 15 will be described.

  A developing cartridge discrimination sensor (not shown) is provided on the side wall of the main body casing. This cartridge discrimination sensor has a detection member and an optical sensor.

  When the process cartridge having the second developing cartridge mounted in the main body casing is mounted, the detection member is rotated by a driving gear (not shown) provided on the side wall of the second developing cartridge, and the cartridge discrimination sensor is turned on. When the first developing cartridge is mounted on the main body housing, the detection member is not rotated and the optical sensor is turned off. Thereby, it is determined whether the first developing cartridge is attached to the process cartridge or the second developing cartridge is attached.

[Operation of control unit]
FIG. 8 shows a series of corrections for the cumulative dot count value and the maximum dot count value stored in the storage unit when a process cartridge is mounted in an image forming apparatus using two types of developing cartridges having different toner storage capacities. It is a flowchart explaining a processing procedure.

  First, the accumulated dot count value b2 and the transmittance a2 of the developing cartridge before the process cartridge having the developing cartridge that is not new is mounted are stored in a predetermined position of the RAM 13e of the storage unit 13c.

  When it is detected by the new product detection unit 12 and the process cartridge attachment / detachment detection unit 11 that the process cartridge 7 having the development cartridge 8 that is not a new product is installed, in step S201, the development cartridge determination unit 15 detects the installed process cartridge. It is determined whether the developing cartridge in 7 is the first developing cartridge or the second developing cartridge.

  In S202, the rewriting unit 16 determines the maximum dot count value of the developing cartridge stored in the RAM 13e before the process cartridge 7 having the developing cartridge that is not new is mounted by the developing cartridge developing cartridge determining unit. Rewrite to the maximum dot count value of the developed cartridge.

  Next, in S203, the agitator 86 provided in the toner storage unit 84 rotates a predetermined number of times, and in S204, the toner remaining amount detection unit 10 detects the remaining amount of toner in the developing cartridge that is not new, and the control unit 13a Then, the transmittance A3 is obtained by the toner remaining amount detecting unit 10.

  In step S205, the control unit 13a acquires the transmittance a2 of the developing cartridge before the process cartridge 7 having the developing cartridge that is not new is mounted, and in step S206, the process cartridge 7 having the developing cartridge that is not new is detected. The transmittance a2 of the developing cartridge before being mounted is compared with the transmittance A3 of the developing cartridge 8 which is not new, and it is determined whether or not the difference is 5% or more.

  If the difference between the transmittance a2 stored at a predetermined position in the RAM 13e and the transmittance A3 of the non-new developer cartridge 8 is 5% or more (S206, Yes), the controller 13a stores the difference in the RAM 13e in S207. The accumulated dot count value b2 is corrected to the accumulated dot count value B3 corresponding to the transmittance A3 based on the table of accumulated dot counter values based on the transmittance stored in the ROM 13d, and the accumulated dot count value B2 is accumulated in the RAM 13e. In the image forming apparatus that stores the count value B3 and uses two types of developing cartridges having different toner storage amounts, the accumulated dot count value and the maximum dot count value stored in the storage unit when the process cartridge is mounted are corrected. End the processing procedure.

  On the other hand, when the difference between the transmittance a2 stored in the predetermined position of the RAM 13e and the transmittance a3 of the non-new developing cartridge is less than 5% (S206, No), the control unit 13a stores the accumulated dots stored in the RAM 13e. In an image forming apparatus that uses two types of developing cartridges having different toner storage amounts without correcting the count value b2, the cumulative dot count value and the maximum dot count value stored in the storage unit when the process cartridge is mounted are calculated. The processing procedure for correction is terminated.

  The effect of the laser printer configured as described above will be described.

  In the laser printer 1 of the present embodiment, the rewriting unit 16 uses the developing cartridge determination unit to determine the maximum dot count value of the developing cartridge stored in the RAM 13e before the process cartridge 7 having a developing cartridge that is not new is mounted. Since the maximum dot count value of the determined developing cartridge is rewritten, even when a toner containing amount is different and a developing cartridge that is not new is mounted, the developing cartridge is displayed to the user based on the usage amount of the replaced developing cartridge. Can tell you exactly when to replace.

(Modification)
The embodiment of the present invention is not limited to the above-described embodiment, and can take various forms as long as it belongs to the technical scope of the present invention.

  In the present embodiment, the attachment / detachment of the process cartridge 7 is detected by the toner remaining amount detection unit 10. For example, by detecting the opening / closing of the cover 21, it is determined whether the process cartridge 7 has been attached / detached. Also good.

  In this embodiment, it is detected whether or not the process cartridge 7 has been attached or detached while all the power sources of the laser printer 1 are in the “On” state. However, when the laser printer 1 is in the “OFF” state, Even when the developing cartridge is replaced with a non-developing cartridge, the same effect can be obtained. Specifically, when the power of the laser printer 1 is changed from “OFF” to “ON”, it is determined that the process cartridge has been attached and detached, and the transmittance and the power before the power is turned “OFF” It is also possible to compare the transmittance after being turned “ON” and correct the accumulated dot count value stored in the RAM 13e when the difference is 5% or more.

  In the present embodiment, the process cartridge 7 is detached from the main body housing 2, the developing cartridge 8 is removed from the detached process cartridge 7, and only the developing cartridge 8 is replaced. However, this is not restrictive. For example, the same effect can be obtained even if only the developing cartridge 8 is removed while the photosensitive member cartridge 71 is mounted in the main body housing 2. The same effect can be obtained even if the entire process cartridge 8 is replaced.

  In the present embodiment, the photosensitive cartridge is provided with the first developing cartridge and the second developing cartridge so that the first developing cartridge and the second developing cartridge can be mounted, but the first developing cartridge, the second developing cartridge, and the second developing cartridge are provided on the photosensitive cartridge. The same effect can be obtained even when the third developing cartridge having a larger amount of toner than the cartridge is provided to be mountable.

DESCRIPTION OF SYMBOLS 1 ... Laser printer, 2 ... Main body housing, 20 ... Process cartridge mounting part, 21 ... Cover, 22 ... Display part, 7 ... Process cartridge, 71 ... Photoconductor Cartridge 72 ... photosensitive cartridge frame 73 ... photosensitive drum 76 ... transmission window 8 ... developing cartridge 81 ... developing cartridge frame 84 ... toner accommodating portion 85 ... Transmission window, 86 ... Agitator, 10 ... Toner remaining amount detection unit, 11 ... Process cartridge attachment / detachment detection unit, 12 ... New article detection unit, 13 ... Control device, 13a ... -Control part, 13c ... Memory | storage part, 13b ... CPU

Claims (4)

In an image forming apparatus for forming an image on a recording medium via a developer,
A cartridge mounting portion on which a cartridge having a storage portion in which a developer is stored is mounted;
A developer remaining amount detecting means for detecting the remaining amount of developer in the cartridge mounted in the cartridge mounting portion;
A developer usage amount estimating means for estimating a usage amount of the developer of the cartridge mounted on the cartridge mounting portion based on an integrated value of the number of dots of image information;
Storage means for storing remaining amount information obtained based on the developer remaining amount detecting means and developer usage amount information obtained based on the developer usage amount estimating means;
The developer remaining amount information stored in the storage unit before the cartridge is pulled out from the cartridge mounting unit, and detected by the developer remaining amount detection unit after the cartridge is newly mounted in the cartridge mounting unit. When the difference from the remaining amount information of the developer becomes a predetermined value or more, based on the remaining amount information of the developer after the cartridge is newly mounted, before the cartridge stored in the storage means is pulled out A control unit for correcting the usage amount information of the developer,
An image forming apparatus comprising: The developer remaining amount detecting means is
A light-emitting element and a light-receiving element, and detecting the remaining amount information of the developer in the cartridge based on the transmittance of the light emitted from the light-emitting element through the storage portion of the cartridge and transmitted to the light-receiving element;
The controller is
The correction is performed when the difference between the transmittance before the cartridge is pulled out from the cartridge mounting portion and the transmittance after the cartridge is newly mounted in the cartridge mounting portion is 5% or more. Item 2. The image forming apparatus according to Item 1. The cartridge mounted on the cartridge mounting portion is provided with an agitator for stirring the developer,
3. The image according to claim 1, wherein the developer remaining amount detecting unit detects the remaining amount of developer in a mounted cartridge after the agitator has rotated a predetermined number of times. Forming equipment. In the cartridge mounting part,
Cartridge discriminating means for discriminating whether any one of at least two types of cartridges having different developer accommodating amounts is mounted;
In the storage unit,
A second storage unit for storing the maximum usable amount of developer of the two types of cartridges;
In the control unit,
4. The rewriting means for rewriting the maximum usable amount of developer before cartridge replacement to the maximum usable amount of developer of the cartridge determined by the cartridge determining means. An image forming apparatus according to claim 1.