Image forming apparatus

Abstract

To provide an image forming apparatus that can stabilize an image at low cost.SOLUTION: According to an embodiment, an image forming apparatus has photoreceptors, static eliminators, electrifiers, an exposure unit, developing units, and a processor. The static eliminator emits static eliminating light with which the photoreceptor is irradiated. The electrifier electrically charges the photoreceptor from which static electricity is eliminated by the static eliminator. The exposure unit forms an electrostatic latent image on the photoreceptor electrically charged by the electrifier. The developing unit supplies toner to the photoreceptor on which the electrostatic latent image is formed by the exposure unit. A toner sensor outputs a signal according to the amount of toner adhered to an image carrier to which the toner is transferred from the photoreceptor. A memory stores a target value that includes a correction value of image stabilization control of stabilizing the image for every type of toner. The processor executes image stabilization control of setting the output value from the toner sensor to the target value including the correction value for every type of toner.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to an image forming apparatus. [Background technology]

[0002] Furthermore, electrophotographic image forming apparatuses form color images using a developer containing toners of multiple colors (e.g., yellow, magenta, cyan, and black). The electrophotographic image forming apparatuses measure the amount of toner attached to a transfer member with a toner sensor, and perform image stabilization control so that the amount of toner measured by the toner sensor becomes a target value.

[0003] On the other hand, in order to reduce the size and cost of an image forming apparatus, it is sometimes desirable to design the apparatus so that the distance between each unit is reduced or some components are omitted. In a design that reduces size and costs, a phenomenon may occur in which a part of the static elimination light irradiated onto the photosensitive drum in the image forming apparatus is incident on the toner sensor. This phenomenon can be prevented by installing a light-shielding wall that blocks the static elimination light in the image forming apparatus, but this creates a problem in that the configuration runs counter to the trend toward size reduction and cost reduction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-150294 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an image forming apparatus capable of stabilizing an image at low cost. [Means for solving the problem]

[0006] According to an embodiment, an image forming apparatus includes a photoconductor, a discharger, a charger, an exposure device, a developer, and a processor. The discharger emits discharge light to be irradiated onto the photoconductor. The charger charges the photoconductor discharged by the discharger. The exposure device forms an electrostatic latent image on the photoconductor charged by the charger. The developer supplies toner to the photoconductor on which the electrostatic latent image has been formed by the exposure device. The toner sensor outputs a signal according to the amount of toner adhesion on the image carrier to which the toner has been transferred from the photoconductor. The memory stores target values ​​including correction values ​​for image stabilization control that stabilizes an image for each type of toner. The processor executes image stabilization control that sets the output value of the toner sensor to be the target value including the correction value for each type of toner. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a digital multifunction peripheral as an image forming apparatus according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of an image forming station in a printer of a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Diagram 3] FIG. 3 is a block diagram showing an example of the configuration of a control system in a digital multifunction peripheral as an image forming apparatus according to an embodiment. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of a toner sensor in a printer of a digital multifunction peripheral as an image forming apparatus according to an embodiment. [Diagram 5] FIG. 5 is a diagram showing an example of the sensor sensitivity of a toner sensor in a printer of a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of the spectral reflectance for each color toner used in a printer of a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Figure 7] FIG. 7 is a diagram showing an example of detection of the amount of black toner adhered to a transfer belt used in a printer of a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Figure 8]FIG. 8 is a diagram showing an example of detection of the amount of yellow toner adhered to a transfer belt used in a printer of a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of the relationship between the sensor sensitivity and the setting value of the toner sensor in a printer of a digital multifunction peripheral as the image forming apparatus according to the embodiment. [Figure 10] FIG. 10 is a diagram showing an example of settings for whether correction is required depending on the wavelength of the static elimination light for toner of each color in a digital multifunction peripheral as an image forming apparatus according to the embodiment. [Figure 11] FIG. 11 is a flowchart for explaining a process of updating a correction value for a target value of image stabilization control in a digital multifunction peripheral as an image forming apparatus according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the present embodiment will be described with reference to the drawings. First, a configuration of a digital multi-functional peripheral (MFP) 1 as an image forming apparatus according to the embodiment will be described. FIG. 1 is a block diagram showing an example of the configuration of a digital multifunction peripheral 1 as an image forming apparatus according to an embodiment. 1, the digital multifunction peripheral 1 includes a printer 2, an operation panel 3, a scanner 4, and a system controller 5. The digital multifunction peripheral 1 is an example of an image forming apparatus that is placed in a workplace or the like.

[0009] The printer 2 is an image forming device that forms an image on a recording medium. The printer 2 included in the digital multifunction device 1 is an image forming device that forms an image on a recording medium by electrophotography. The printer 2 forms an image (toner image) on a recording medium such as paper using toner. The recording medium on which the printer 2 forms an image may be any medium on which an image can be formed, and is not limited to paper, and may be cloth, a plastic film, or a sheet, etc.

[0010] The scanner 4 is installed on the upper part of the main body of the digital multifunction device 1. The scanner 4 is a device that optically reads an image of an original. For example, the scanner 4 reads an image of an original set on a platen glass. The scanner 4 may also be configured to include a scanner that reads an image of an original conveyed by an automatic document feeder (ADF).

[0011] The operation panel 3 is a user interface. The operation panel 3 has a display unit (display), a touch panel, and operation buttons. The operation panel 3 displays operation guides and the like on the display unit. The operation panel 3 accepts operation instructions from the user via the touch panel and operation buttons. For example, the operation panel 3 has a touch panel on the display screen of the display unit, and detects a portion of the display screen touched by the user.

[0012] The system controller 5 controls the entire digital multifunction peripheral 1. The system controller 5 receives operation instructions input to the operation panel 3 and controls the operation of each section. The system controller 5 also receives operation instructions from external devices connected via an interface and controls the operation of each section. For example, when an instruction is given to form an image on a recording medium, the system controller 5 controls the printer 2 to cause the printer 2 to form an image on the recording medium.

[0013] The configuration of the printer 2 will now be described. As shown in FIG. 1, the printer 2 has a medium supply mechanism 13, a conveying mechanism 15, multiple image forming stations SY, SM, SC, SK, an intermediate transfer belt (transfer belt) 21, a secondary transfer roller 22, a support roller 23, a toner sensor 24, a transfer belt cleaner 25, and a fixing unit 26.

[0014] The medium supply mechanism 13 has a plurality of paper feed cassettes 321, 322, 323. Any number of paper feed cassettes may be used. Each of the paper feed cassettes 321, 322, 323 stores paper as the recording medium S. The paper as the recording medium S stored in each paper feed cassette may be of different sizes or types. Pickup rollers 341, 342, 343 are disposed in each of the paper feed cassettes 321, 322, 323. The pickup rollers 341, 342, 343 pick up sheets of paper as recording media one by one from the paper feed cassettes 321, 322, 323, respectively. The pickup rollers 341, 342, 343 supply the picked up recording media S to the transport mechanism 15.

[0015] The transport mechanism 15 transports the recording medium S. The transport mechanism 15 has first transport rollers 521, 522, and 523, a second transport roller 54, and a registration roller 56 in a transport path before an image is formed on the recording medium S. The transport mechanism 15 transports the recording medium S supplied by the pickup rollers 341, 342, and 343 from the first transport rollers 521, 522, and 523 to the second transport roller 54. In the transport mechanism 15, the second transport roller 54 further transports the recording medium S to the registration roller 56.

[0016] The registration rollers 56 of the transport mechanism 15 transport the recording medium S to a secondary transfer position, which will be described later, in accordance with the timing at which an image is transferred from the intermediate transfer belt 21 to the recording medium S at the secondary transfer position. The transport mechanism 15 configures a transport path so as to transport the recording medium S, onto which the image has been transferred from the intermediate transfer belt 21, to the fixing device 26. The transport mechanism 15 further includes a third transport roller 58 for discharging the paper to a paper discharge section, and a transport mechanism for transporting the recording medium S to an inversion section that inverts the recording medium S.

[0017] Each of the image forming stations SY, SM, SC, and SK forms an image using toner. In this embodiment, the image forming station SY forms a yellow image. The image forming station SM forms a magenta image. The image forming station SC forms a cyan image. The image forming station SK forms a black image. Each of the image forming stations SY, SM, SC, and SK transfers the image formed using toner onto the intermediate transfer belt 21. The configuration of each of the image forming stations SY, SM, SC, and SK will be described in detail later.

[0018] The intermediate transfer belt 21 is a medium (image carrier) that holds the images transferred by each of the image forming stations SY, SM, SC, and SK. The intermediate transfer belt 21 is an endless belt as shown in Fig. 1. The intermediate transfer belt 21 moves in the direction indicated by the arrow a in Fig. 1. The intermediate transfer belt 21 moves the images transferred by each of the image forming stations SY, SM, SC, and SK to a position where the secondary transfer roller 22 and the support roller 23 face each other.

[0019] The secondary transfer roller 22 and the support roller 23 constitute a transfer section (secondary transfer section) that transfers an image from the intermediate transfer belt 21 to the recording medium. The position where the secondary transfer roller 22 and the support roller 23 face each other is the secondary transfer position where an image is transferred from the intermediate transfer belt 21 to the recording medium. The secondary transfer roller 22 and the support roller 23 sandwich the intermediate transfer belt 21 and the recording medium at the secondary transfer position.

[0020] The support roller 23 supports the intermediate transfer belt 21. The support roller 23 is a drive roller that drives the intermediate transfer belt 21. The secondary transfer roller 22 faces the support roller 23 across the intermediate transfer belt 21. The secondary transfer roller 22 transfers (secondary transfer) an image formed with toner on the transfer surface of the intermediate transfer belt 21 onto the surface of a recording medium.

[0021] The toner sensor 24 is a sensor that detects the amount (concentration) of toner. The toner sensor 24 detects the amount of toner attached on the intermediate transfer belt 21. The toner sensor 24 is disposed facing the transfer surface of the intermediate transfer belt 21. The toner sensor 24 is provided between the image transfer position (primary transfer position) and the secondary transfer position of each image forming station in the movement direction a of the intermediate transfer belt 21. The toner sensor 24 outputs the detected amount of toner attached to the system controller 5.

[0022] 1, the transfer belt cleaner 25 is disposed between the secondary transfer position and the primary transfer position in the moving direction a of the intermediate transfer belt 21. The transfer belt cleaner 25 removes toner on the intermediate transfer belt 21. For example, the transfer belt cleaner 25 removes toner remaining on the transfer surface of the intermediate transfer belt 21 after an image is transferred from the intermediate transfer belt 21 to a recording medium.

[0023] The fixing device 26 fixes the image formed by the toner transferred to the recording medium to the recording medium. The fixing device 26 is disposed on the transport path of the recording medium after it has passed the secondary transfer position. The fixing device 26 has a pressure roller and a heating roller that face each other. The fixing device 26 applies heat and pressure to the recording medium by transporting the recording medium between the opposing heating roller and pressure roller. The fixing device 26 fixes the toner image transferred to the recording medium by heating it in a pressurized state.

[0024] Next, the configuration of each of the image forming stations SY, SM, SC, and SK in the printer 2 as the image forming apparatus according to the embodiment will be described in detail. FIG. 2 is a diagram showing an example of the configuration of each of the image forming stations SY, SM, SC, and SK in the printer 2. As shown in FIG. 2, each of the image forming stations SY, SM, SC, and SK includes an exposure unit 100, a developing unit 110, a photoconductor drum 122, a charger 126, a primary transfer roller 128, a photoconductor cleaner 130, and a static eliminator 132. In this embodiment, each of the image forming stations SY, SM, SC, and SK has the configuration shown in FIG.

[0025] The photoconductor drum 122 is an image carrier having a photoconductor layer 124 on its surface. The photoconductor drum 122 rotates in a direction (indicated by arrow b in FIG. 2) that matches the movement of the intermediate transfer belt 21 in the moving direction a. Around the photoconductor drum 122, a charger 126, an exposure unit 100, a developer 110, a primary transfer roller 128, the intermediate transfer belt 21, a photoconductor cleaner 130, and a static eliminator 132 are arranged.

[0026] The charger 126 uniformly charges the photoconductor layer 124 on the surface of the photoconductor drum 122. The charger 126 uniformly charges the photoconductor layer 124 on the surface of the photoconductor drum 122 to a negative polarity, for example.

[0027] The exposure unit 100 forms a static electricity pattern (electrostatic latent image) corresponding to an image on the surface of the photoconductor drum 122. The exposure unit 100 irradiates the surface of the photoconductor drum 122 with light L, the emission of which is controlled based on image data. For example, the exposure unit 100 irradiates the surface of the photoconductor drum 122 with light L, which is emitted based on image data, via an optical system such as a polygon mirror. The exposure unit 100 may be configured to include a device that emits a plurality of laser beams that are guided to the photoconductor drums 122 of a plurality of image forming stations. Furthermore, the exposure unit 100 may be a light emitting device provided for each of the plurality of image forming stations.

[0028] The developing unit 110 develops the electrostatic latent image formed on the surface of the photoconductor drum 122 with a developer. The developing unit 110 supplies the developer D to the surface of the photoconductor drum 122 exposed by the exposure unit 100. The developing unit 110 of each image forming station develops an image in its corresponding color. The developer D is a mixture of a carrier made of magnetic fine particles and a toner. When the developer D is stirred, the toner is triboelectrically charged. As a result, the toner adheres to the electrostatic latent image formed on the surface of the photoconductor drum 122 by electrostatic force.

[0029] For example, the developer 110 of the image forming station SY develops the electrostatic latent image on the photoconductor drum 122 with yellow toner. The developer 110 of the image forming station SM develops the electrostatic latent image on the photoconductor drum 122 with magenta toner. The developer 110 of the image forming station SC develops the electrostatic latent image on the photoconductor drum 122 with cyan toner. The developer 110 of the image forming station SK develops the electrostatic latent image on the photoconductor drum 122 with black toner.

[0030] An image (toner image) developed with toner on the surface of the photosensitive drum 122 moves to a position corresponding to the primary transfer roller 128 by the rotation of the photosensitive drum 122. The primary transfer roller 128 faces the photosensitive drum 122 with the intermediate transfer belt 21 sandwiched therebetween. The primary transfer roller 128 abuts against the surface of the photosensitive drum 122 with the intermediate transfer belt 21 sandwiched therebetween. The primary transfer roller 128 transfers the toner image on the surface of the photosensitive drum 122 to the intermediate transfer belt 21 (primary transfer).

[0031] The photoconductor cleaner 130 is disposed downstream, in the circumferential direction of the photoconductor drum 122, of the position where the toner image on the surface of the photoconductor drum 122 is transferred onto the intermediate transfer belt 21. The photoconductor cleaner 130 removes the toner on the surface of the photoconductor drum 122. That is, the photoconductor cleaner 130 removes the toner remaining on the surface of the photoconductor drum 122 after the primary transfer of the toner image from the photoconductor drum 122 to the intermediate transfer belt 21 is executed.

[0032] The static eliminator 132 is disposed downstream of the position of the photoconductor cleaner 130 in the circumferential direction of the photoconductor drum 122. The static eliminator 132 emits light (static elimination light) that removes electric charges remaining on the photoconductor layer 124 on the surface of the photoconductor drum 122. The static eliminator 132 emits the static elimination light from a light source constituted by an LED or the like. The static eliminator 132 is disposed so that the static elimination light emitted by the light source is irradiated onto the surface of the photoconductor drum 122.

[0033] In the image forming apparatus according to the present embodiment, a part of the light (static removal light) emitted by the light source of the static remover 132 of the image forming station SK is incident on the toner sensor 24 as leakage light. According to the example shown in FIG. 2, the leakage light from the light source of the static remover 132 is reflected by the intermediate transfer belt 21 as shown by the dotted line in FIG. 2, and is incident on the toner sensor 24. The image forming apparatus according to the present embodiment performs highly accurate measurement of the donor adhesion amount using the toner sensor 24 without installing a light-shielding wall for blocking the leakage light from the light source of the static remover 132. That is, the image forming apparatus according to the present embodiment is premised on a structure in which a part of the static removal light (leakage light) from the static remover 132 is incident on the toner sensor 24.

[0034] Next, the configuration of a control system in the digital multifunction peripheral 1 serving as the image forming apparatus according to the embodiment will be described. FIG. 3 is a block diagram showing an example of the configuration of a control system in a digital multifunction peripheral 1 serving as an image forming apparatus according to an embodiment. 3, the system controller 5 includes a processor 101, a ROM 102, a RAM 103, a storage device 104, and a communication interface (I / F) 105. The processor 101 of the system controller 5 is connected to each unit in the digital multifunction peripheral 1 via various interfaces.

[0035] The processor 101 executes a program to realize various processes. The processor 101 is, for example, a CPU. The processor 101 is connected to a ROM 102, a RAM 103, a storage device 104, a communication interface (I / F) 105, and the like. The processor 101 is also connected to each part in the printer 2, an operation panel 3, and a scanner 4 via the interfaces.

[0036] The ROM 102 is a non-rewritable non-volatile memory. The ROM 102 operates as a program memory for storing programs. The RAM 103 operates as a working memory or a buffer memory. The processor 101 executes various processes by using the RAM 103 to execute programs stored in the ROM 102 or the storage device 104.

[0037] The storage device 104 is a rewritable non-volatile memory. For example, the storage device 104 is configured with a storage device such as an HDD (hard disk drive) or an SSD (solid state drive). The storage device 104 stores data such as control data, control programs, and setting information. The storage device 104 also stores image data and the like.

[0038] The communication I / F 105 is an interface for performing data communication with an external device. For example, the communication I / F 105 communicates with a user terminal such as a PC or a mobile terminal via a network. The communication I / F 105 may input an image print request (print job) from a user terminal such as a PC.

[0039] Next, the operation of the image forming process in the printer 2 as the image forming apparatus according to the embodiment will be described. The digital multifunction device 1 executes an image forming process of acquiring an image to be formed on a recording medium S and printing the acquired image on the recording medium S by the printer 2. For example, when a copy command is issued on the operation panel 3, the processor 101 of the system controller 5 executes a process of printing an image of an original document read by the scanner 4 on the recording medium S by the printer 2.

[0040] When executing image forming processing, the processor 101 of the system controller 5 takes in the recording medium S stored in the storage unit by the medium supply mechanism 13. The processor 101 causes the conveying mechanism 15 to convey the recording medium S supplied from the medium supply mechanism 13 in the printer 2 to a position just before the registration rollers 56.

[0041] Furthermore, the processor 101 of the system controller 5 generates images to be formed by each of the image forming stations SY, SM, SC, and SK based on an image (print image) to be printed on the recording medium S. For example, the processor 101 generates images of each color (yellow, magenta, cyan, and black) to be formed by each of the image forming stations SY, SM, SC, and SK from the print image. After generating images of each color from the print image, the processor 101 causes each image forming station to form the generated image of each color.

[0042] In each of the image forming stations SY, SM, SC, and SK, the charger 126 charges the photoconductor layer 124 of the photoconductor drum 122 with a charging bias voltage from a power supply circuit. The processor 101 adjusts (sets) the charging bias voltage by image stabilization control (image quality maintenance control). The exposure device 100 irradiates the photoconductor drum 122 of each of the image forming stations SY, SM, SC, and SK with light to form an electrostatic latent image corresponding to the image of each color. The processor 101 adjusts (sets) the power of the light output by the exposure device 100 by image stabilization control. In each of the image forming stations SY, SM, SC, and SK, an electrostatic latent image is formed on the photoconductor layer 124 of the photoconductor drum 122 by the light irradiated from the exposure device 100.

[0043] Each of the image forming stations SY, SM, SC, and SK develops the electrostatic latent image on the photosensitive drum 122 with the toner of the color contained in the developer 110. In each of the image forming stations SY, SM, SC, and SK, the developing roller rotates while carrying the developer D containing the toner of the respective color supplied from the developer container. Here, the concentration ratio of the developer D is adjusted (set) by image stabilization control. The developing roller carrying the developer D is applied with a developing bias voltage from a power supply circuit. The developing roller 110 supplies the toner in the developer carried by the developing roller to the electrostatic latent image by the potential difference (contrast potential) between the potential on the developing roller and the electrostatic latent image on the photosensitive drum 122. The processor 101 adjusts (sets) the developing bias voltage, contrast potential, and the like by image stabilization control.

[0044] In each of the image forming stations SY, SM, SC, and SK, the photoconductor drum 122 moves an image (toner image) developed by the developer 110 to a position (primary transfer position) facing the primary transfer roller 128. At the primary transfer position, the photoconductor drum 122 faces the primary transfer roller 128 with the intermediate transfer belt 21 sandwiched therebetween. A primary transfer bias voltage is applied to the primary transfer roller 128 from a power supply circuit. The toner image on the photoconductor drum 122 is transferred to the intermediate transfer belt 21 by the primary transfer roller to which the primary transfer bias voltage is applied at the primary transfer position. When a color image is formed, each of the image forming stations SY, SM, SC, and SK transfers the toner images of each color onto the intermediate transfer belt 21 in an overlapping manner. As a result, a color image in which the toner images of each color are overlapped is transferred onto the intermediate transfer belt 21.

[0045] The intermediate transfer belt 21 moves the transferred toner image to a position (secondary transfer position) facing the secondary transfer roller 22. The registration roller 56 sends the recording medium S to the secondary transfer position in synchronization with the position of the image transferred onto the intermediate transfer belt 21. As a result, the secondary transfer roller 22 and the support roller 23 convey the overlapping intermediate transfer belt 21 and recording medium S in a sandwiched state at the secondary transfer position. A secondary transfer bias voltage from a power supply circuit is applied to the secondary transfer roller 22. The toner image on the intermediate transfer belt 21 is transferred to the recording medium S by the secondary transfer roller 22 to which the secondary transfer bias voltage is applied at the secondary transfer position.

[0046] The recording medium S that has passed the secondary transfer position is conveyed to the fixing device 26. The fixing device 26 fixes the toner image transferred from the intermediate transfer belt 21 to the recording medium S at the secondary transfer position onto the recording medium S. The fixing device 26 applies heat and pressure to the recording medium S onto which the toner image has been transferred, thereby fixing the toner image onto the recording medium S. The recording medium S that has passed through the fixing device 26 is discharged from the paper discharge section with the toner image fixed thereto.

[0047] Next, image stabilization control using the toner sensor 24 in the digital multifunction peripheral 1 as the image forming apparatus according to the embodiment will be described. The system controller 5 executes image stabilization control, which performs adjustments (settings) to stabilize the image formed on the recording medium S by the image forming process by the printer 2. The image stabilization control is executed, for example, at a predetermined cycle. The image stabilization control may be executed every time a predetermined execution condition is satisfied, or may be executed at any timing. The image stabilization control is executed using the output of the toner sensor 24.

[0048] Hereinafter, as an example of image stabilization control, a description will be given of density adjustment using the output of the toner sensor 24. However, the image stabilization control may be any process that is executed using the output of the toner sensor 24, and may be a process that changes a setting value for image position adjustment, image gradation adjustment, or the like.

[0049] Density adjustment, which is an example of image stabilization control, is a process of adjusting the density of an image formed on the recording medium S by the image formation process by the printer 2. The density of the image formed on the recording medium S varies depending on the amount (density) of toner supplied from the development roller to the electrostatic latent image on the photosensitive drum 122 when the electrostatic latent image is developed. In density adjustment, the system controller 5 adjusts (sets) various control setting values ​​so that the output value of the toner sensor 24 becomes a target value indicating the target amount of toner adhesion. For example, the system controller 5 adjusts setting values ​​such as the charging bias, development bias, exposure power, and developer concentration ratio so that the output value of the toner sensor 24 becomes a target value.

[0050] The reference target value in the density adjustment is determined based on the relationship between the output value of the toner sensor 24 in the digital multifunction printer 1 and the amount of toner adhesion on the transfer belt 21. The reference target value in the density adjustment is stored in a memory such as the storage device 104 for each color of toner. However, in the digital multifunction printer 1 according to the present embodiment, for a color of toner that requires correction, which will be described later, a target value including a correction value is stored in a memory such as the storage device 104. The memory such as the storage device 104 stores a target value obtained by adding a correction value to a reference target value as a target value including a correction value for each type of toner. The memory such as the storage device 104 may also store a reference target value and a correction value as a target value including a correction value for each type of toner. The digital multifunction printer 1 executes image stabilization control so that the target value obtained by adding a correction value to a reference target value is obtained for a type of toner for which a correction value is set.

[0051] Next, the toner sensor 24 in the digital multifunction peripheral 1 serving as the image forming apparatus according to the embodiment will be described. FIG. 4 is a diagram showing an example of the configuration of the toner sensor 24 in the digital multifunction peripheral 1 as the image forming apparatus according to the embodiment. The toner sensor 24 is a sensor that measures the amount of toner adhesion by reading reflected light from the belt surface, utilizing the smoothness of the surface of the transfer belt 21 and the unevenness caused by the toner. The toner sensor 24 is, for example, a reflective sensor that combines a light-emitting element and a light-receiving element. An image forming apparatus that forms a color image uses toner of multiple colors. The optical characteristics of toner differ depending on the color. For this reason, the toner sensor 24 in the configuration example shown in FIG. 4 uses one light-emitting element and two light-receiving elements to read the amount of toner adhesion of each color with high accuracy.

[0052] In the configuration example shown in FIG. 4, the toner sensor 24 has a light emitting element 201, a first light receiving element 202, and a second light receiving element 203. The light emitting element 201 emits detection light to be irradiated onto a portion (the surface of the transfer belt 21) to be a detection surface. The light emitting element 201 is, for example, an LED. The first light receiving element 202 and the second light receiving element 203 are configured with a PD (photodiode) or a PTr (phototransistor). The first light receiving element 202 is a specular reflection light receiving element that detects specular reflection light of the light (incident light) from the light emitting element 201 on the detection surface. The second light receiving element 203 is a diffuse reflection light receiving element that detects diffuse reflection light on the detection surface.

[0053] The amount of toner adhesion on the detection surface (surface on transfer belt 21) is detected by the detection results of first light receiving element 202 and second light receiving element 203. For example, black toner adhered to transfer belt 21, which is the detection surface, hardly diffuses and reflects light (incident light) irradiated from light emitting element 201. For this reason, when black toner adheres to the detection surface, the output value of second light receiving element 203 hardly increases. On the other hand, when black toner adheres to the detection surface, first light receiving element 202 has an output value according to the amount of toner adhesion.

[0054] In contrast, toners such as yellow, cyan, and magenta diffuse and reflect incident light according to the characteristics of their respective colors. Therefore, when yellow, cyan, or magenta toner is attached to the detection surface, the second light receiving element 203 receives light diffused by the toner. For example, when yellow toner is attached to the detection surface, the second light receiving element 203 receives light diffused by the yellow toner, and the output value increases according to the characteristics of yellow.

[0055] As described above, the toner sensor 24 outputs information indicating the amount of toner adhesion of each color by combining the output value of the first light receiving element 202 and the output value of the second light receiving element 203. In other words, the amount of toner adhesion on the detection surface is detected (measured) by combining and calculating the output value of the first light receiving element 202 and the output value of the second light receiving element 203.

[0056] The toner sensor 24 may be a sensor in which a beam splitter is provided on the optical path from the light-emitting side to the light-receiving side. In this case, the toner sensor is composed of a light-emitting element, a beam splitter, and first and second light-receiving elements. The beam splitter splits the light from the light-emitting element into P-wave light (specularly reflected light) and S-wave light (diffusely reflected light). The first light-receiving element receives the P-wave light (specularly reflected light) from the beam splitter. The second light-receiving element receives the S-wave light (diffusely reflected light) from the beam splitter.

[0057] The toner sensor 24 configured as described above may have a reading difference (sensor sensitivity) in the output value (reading value) for a certain amount of toner adhesion. Therefore, in order to keep the amount of toner adhesion on the transfer belt 21 constant, it is necessary to set a target value in density adjustment for each sensor sensitivity of the toner sensor 24. In general, the reference target value in density adjustment is set according to the sensor sensitivity specified from information at the manufacturing stage of the toner sensor and information at the manufacturing stage of the digital multifunction printer 1. The reference target value in density adjustment may also be set according to the reading result of a reference seal for measuring the sensor sensitivity that is provided in advance.

[0058] FIG. 5 is a diagram showing an example of a read value of the toner sensor 24 relative to the amount of toner adhesion on the transfer belt 21. As shown in FIG. The example shown in Fig. 5 shows the upper and lower limit read values ​​of the toner sensor 24 with respect to toner adhesion. As shown in Fig. 5, the toner sensor 24 produces different read values ​​for a specific amount of toner adhesion due to differences in sensor sensitivity. A target value is set for the output value of the toner sensor 24 for each toner color. Therefore, the target value for the toner sensor 24 for each toner color is set for each sensor sensitivity.

[0059] Next, the influence of leakage light of the light (static elimination light) emitted by the static eliminator 132 on the output of the toner sensor 24 will be described. When the output of the toner sensor 24 is not affected by the static elimination light, the toner adhesion amount becomes a predetermined target amount by adjusting the output value of the toner sensor 24 to the reference target value for density adjustment. However, when there is an effect of leakage light from the static elimination light, the toner adhesion amount may vary even if the output value of the toner sensor 24 is adjusted to the reference target value.

[0060] FIG. 6 is a diagram showing an example of the amount of attached black toner when leakage light of the static elimination light is incident on the toner sensor 24 and when no static elimination light is incident thereon. The toner adhesion amount KTa indicates the amount of black toner that adheres to the transfer belt 21 when adjusted to a reference target value for density adjustment in a state where no leakage light is incident on the toner sensor 24. Moreover, the toner adhesion amount KTb indicates the amount of black toner that adheres to the transfer belt 21 when adjusted to a reference target value for density adjustment in a state where leakage light is incident on the toner sensor 24. According to the example shown in Fig. 6, the difference between the toner adhesion amount KTa and the toner adhesion amount KTb is small, and it is considered that the effect on the image actually printed on the recording medium is small.

[0061] FIG. 7 is a diagram showing an example of the amount of attached yellow toner when leakage light of the static elimination light is incident on the toner sensor 24 and when no static elimination light is incident thereon. The toner adhesion amount YTa indicates the amount of yellow toner that adheres to the transfer belt 21 when the toner adhesion amount is adjusted to the reference target value for density adjustment in a state where no leakage light is incident on the toner sensor 24. The toner adhesion amount KTb indicates the amount of black toner that adheres to the transfer belt 21 when the toner adhesion amount is adjusted to the reference target value for density adjustment in a state where leakage light is incident on the toner sensor 24. According to the example shown in Fig. 7, the difference between the toner adhesion amount YTa and the toner adhesion amount YTb is large, and it is considered that the influence on the image actually printed on the recording medium is large. Therefore, in order to stabilize the adhesion amount of yellow toner as an image stabilization control, it is necessary to correct the influence of the leakage light of the static elimination light.

[0062] 6 and 7, the amount of adhered yellow toner is greatly affected by leakage light (static removal light), whereas the amount of adhered black toner is not (is only slightly) affected by leakage light. Thus, the influence of static removal light differs depending on the type (color) of toner. As shown in FIG. 2, the digital multifunction machine 1 as the image forming apparatus according to the embodiment has a structure in which leakage light of static removal light from the static removal device 132 enters the toner sensor 24. For this reason, the digital multifunction machine 1 according to the embodiment corrects (corrects) the influence of leakage light for each type of toner in image stabilization control such as density adjustment.

[0063] Next, the influence of leakage light of the charge removing light on various toners will be described. 6 and 7, the reason why the effect of the static elimination light varies depending on the type of toner is thought to be that the spectral reflectance of various toners varies depending on the wavelength of the static elimination light. The toner sensor 24 detects the amount of adhesion of each color of toner by detecting diffused light with the second light receiving element 203. Therefore, it is thought that the output value of the toner sensor 24 fluctuates greatly when detecting (measuring) the amount of adhesion of toner whose spectral reflectance is high at the wavelength of the static elimination light.

[0064] FIG. 8 is a diagram showing the spectral reflectance of various toners relative to the wavelength of irradiated light. In Fig. 8, curves Y, M, C, and K represent the spectral reflectance of yellow toner, magenta toner, cyan toner, and black toner, respectively. Also in Fig. 8, wavelength P is the wavelength of light emitted by light-emitting element 201 of toner sensor 24. In the example shown in Fig. 8, wavelength P of light emitted by light-emitting element 201 of toner sensor 24 is approximately 650 to 670 nm.

[0065] As shown in FIG. 8, various toners have different spectral reflectances for the wavelength of irradiated light. Furthermore, the spectral reflectance of various toners varies depending on the wavelength of irradiated light. As shown in FIG. 2, in an image forming apparatus configured such that leakage light of static elimination light from static eliminator 132 enters toner sensor 24, an influence according to the wavelength of static elimination light occurs for each type (color) of toner. In the image forming apparatus, static eliminator 132 emits static elimination light of a specific wavelength. In this case, the amount of influence of static elimination light (leakage light) of a specific wavelength that appears in the output of toner sensor 24 can be grasped for each type (color) of toner.

[0066] Next, correction of a target value (set value) used for density adjustment as image stabilization control in accordance with the influence of leakage light of the static elimination light on various toners will be described. In order to suppress density variations and stabilize images, the digital multifunction printer 1 corrects the reference target value of density adjustment for each type (color) of toner according to the amount of influence of leakage of static elimination light. As described above, the set value (target value) of image stabilization control such as density adjustment is set according to the sensor sensitivity of the toner sensor 24. The amount of influence of static elimination light on the output of the toner sensor 24 also varies depending on the sensor sensitivity. Therefore, the target value of image stabilization control such as density adjustment is corrected by adding a correction value equivalent to the amount of influence of static elimination light according to the sensor sensitivity.

[0067] For example, in the system controller 5, the storage device 104 stores a target value obtained by correcting a reference target value according to the sensor sensitivity for each toner with a correction value according to the influence of the static elimination light. The storage device 104 may also store a reference target value and a correction value according to the influence of the static elimination light for each toner. The processor 101 of the system controller 5 executes image stabilization control using a target value obtained by correcting a reference target value for each toner with a correction value according to the influence of the static elimination light. This enables the digital multifunction printer 1 to stabilize an image by suppressing variations in density for a specific toner, excluding the influence of leakage light of the static elimination light.

[0068] FIG. 9 is a diagram showing an example of setting values ​​(target values) of the image stabilization control according to the sensor sensitivity of the toner sensor 24. As shown in FIG. In Fig. 9, Linear La shows an example of a set value when there is no influence of leakage light of static elimination light (a reference target value without correction according to the influence amount of static elimination light). Linear Lb shows an example of a set value (a corrected target value) to which a correction value according to the influence amount of leakage light of static elimination light is added. According to the example shown in Fig. 9, if the sensor sensitivity is lower than the intersection point of Linear La and Linear Lb, the target value of the image stabilization control is corrected to be smaller. Also, if the sensor sensitivity is higher than the intersection point of Linear La and Linear Lb, the target value of the image stabilization control is corrected to be larger.

[0069] As described above, the image forming apparatus according to the embodiment corrects the target value for the output value of the toner sensor used for image stabilization control such as density adjustment according to the influence of the static elimination light. The image forming apparatus performs image stabilization control such as density adjustment of each toner using the corrected setting value according to the influence of the static elimination light. This allows the image forming apparatus to suppress the variation in the output of the toner sensor caused by the leakage light from the static eliminator, and enables image stabilization control with suppressed density variation.

[0070] Next, correction of a target value (setting value) used in image stabilization control according to the influence of leakage light of static elimination light on various types of toner will be described. According to the example shown in FIG. 8, black toner (curve K) has a low spectral reflectance regardless of the wavelength of the irradiated light. On the other hand, yellow toner (curve Y), magenta toner (curve M), and cyan toner (curve C) have different wavelengths at which the spectral reflectance is high and low. When the spectral reflectance is low, the toner sensor 24 has a small fluctuation in the output value caused by the static elimination light. If the fluctuation in the output value of the toner sensor 24 caused by the static elimination light is small, the leakage light of the static elimination light hardly affects the detection of the toner adhesion amount. For this reason, for toners with a low spectral reflectance with respect to the wavelength of the static elimination light, correction according to the influence of the static elimination light may not be necessary. Therefore, the image forming apparatus may determine the toners that require correction for the influence of the static elimination light according to the wavelength of the static eliminator 132.

[0071] In the example shown in FIG. 8, when the wavelength of the irradiation light is 650 nm, the yellow and magenta toners have high spectral reflectance, and the cyan and black toners have low spectral reflectance. When the wavelength of the static elimination light includes 650 nm, the output of the toner sensor 24 is strongly affected by the static elimination light if the detection target is yellow or magenta toner. When the wavelength of the static elimination light includes 650 nm, the output of the toner sensor 24 is hardly affected by the static elimination light if the detection target is cyan or black toner. When the wavelength of the static elimination light includes 650 nm, the reference target value for cyan or black toner is not corrected, and the reference target value for yellow and magenta toner is corrected. In this case, the image forming apparatus adds a correction value according to the influence of the static elimination light to the reference target value for yellow and magenta toner.

[0072] FIG. 10 is a diagram showing an example in which the presence or absence of correction according to the influence amount of the static elimination light is set for each type of toner in accordance with the wavelength of the static elimination light. FIG. 10 shows an example in which the presence or absence of correction is set according to the influence of the static elimination light based on the spectral reflectance of various toners as shown in FIG. 7. For example, in the example shown in FIG. 7, if the spectral reflectance is about 10% or less, the reference target value of the image stabilization control is not required to be corrected. In this case, if the wavelength of the static elimination light is 400 nm or less, the reference target value of the image stabilization control for the yellow, magenta, cyan, and black toners is not required to be corrected (no correction). Also, if the wavelength of the static elimination light is 400 to 480 nm, the reference target value for the yellow and black toners is not required to be corrected. If the wavelength of the static elimination light is 480 to 570 nm, the reference target value for the magenta and black toners is not required to be corrected. If the wavelength of the static elimination light is 570 nm or more, the reference target value for the cyan and black toners is not required to be corrected.

[0073] To summarize whether or not correction should be performed for each wavelength, a table is obtained for determining whether or not correction should be performed for each toner color according to the amount of influence of the static elimination light in accordance with the wavelength of the static elimination light, as shown in Fig. 10. For example, an image forming apparatus in which the wavelength of the static elimination light is 570 nm or more determines that the reference target values ​​for yellow and magenta toner should be corrected. In this case, the image forming apparatus stores target values ​​for yellow and magenta in storage device 104, which are obtained by correcting the reference target values ​​with correction values ​​according to the amount of influence of the static elimination light.

[0074] As described above, the image forming apparatus according to the embodiment determines the type (color) of toner to be corrected according to the influence of the static elimination light based on the wavelength of the static elimination light. The image forming apparatus stores in memory a target value including a correction value for image stabilization control for toner determined to require correction based on the wavelength of the static elimination light. This allows the image forming apparatus to identify whether or not correction according to the influence of the static elimination light is required for each type of toner. As a result, the image forming apparatus is able to perform image stabilization control that removes the influence of the static elimination light with high accuracy, without having to install a member for blocking leakage light of the static elimination light.

[0075] Next, updating of the correction value according to the influence amount of the static elimination light in the digital multifunction peripheral 1 serving as the image forming apparatus according to the embodiment will be described. The digital multifunction machine 1 as an image forming apparatus may update the correction value according to the influence amount of the static elimination light in accordance with a predetermined update condition. In the digital multifunction machine 1, it is assumed that the influence amount of the static elimination light in detecting the amount of toner adhesion using the toner sensor 24 varies depending on the degree of use or changes over time. This is because the state of each part constituting the printer 2 changes depending on the degree of use or changes over time.

[0076] For example, it is assumed that the state of light resulting from the static eliminator light (leakage light) emitted by the static eliminator 132 and incident on the toner sensor 24 changes with the degree of use or with the passage of time. As a specific example, it is assumed that when the printer 2 repeats an image formation process, the amount of light emitted by the static eliminator 132 changes and the static eliminator 132 becomes dirty with toner or the like. If the state of the static eliminator light emitted by the static eliminator 132 changes, the amount of influence of the static eliminator light on the detection of the amount of toner adhesion using the toner sensor 24 also changes.

[0077] Fluctuations in the amount of influence of the static elimination light due to the degree of use or the passage of time in the digital multifunction device 1 are estimated in advance. If the fluctuations in the amount of influence of the static elimination light can be estimated, a correction value according to the amount of influence of the static elimination light under update conditions such as the degree of use or the passage of time can be set in advance. The storage device 104 stores correction values ​​according to the amount of influence of the static elimination light under predetermined update conditions such as the degree of use or the passage of time. As a result, when the degree of use or the passage of time reaches the update condition, the digital multifunction device 1 updates the correction value for the target value of the image stabilization control to a correction value according to the update condition.

[0078] The update conditions for updating the correction value for the target value of the image stabilization control include the number of recording media on which printing has been performed (number of prints), the driving time or elapsed time of a specific unit, and the like. For example, when it is assumed that the state of the static elimination light changes due to repeated printing, the digital multifunction machine 1 sets a predetermined number of prints as an update condition for the correction value. In this case, the system controller 5 stores in advance in the storage device 104 a correction value according to the influence of the static elimination light when the predetermined number of prints set as the update condition is printed. The processor 101 of the system controller 5 saves a cumulative value of the number of prints (cumulative number of prints) in the storage device 104 every time printing is executed. When the cumulative number of prints reaches the predetermined number of prints of the update condition, the processor 101 updates the reference target value to a corrected target value using the correction value according to the predetermined number of prints stored in the storage device 104.

[0079] In addition, when it is assumed that the state of the static elimination light changes according to the drive time (accumulated drive time) of a specific unit, the digital multifunction device 1 may set a drive time as a condition for updating the correction value. The drive time as a condition for updating the correction value may be the drive time of the photoconductor drum 122, the drive time of the developing device 110, or the drive time of the transfer belt 21, etc.

[0080] For example, when the system controller 5 sets an update condition for the drive time of the photoconductor drum 122, the system controller 5 stores a correction value corresponding to a predetermined drive time as the update condition in the storage device 104. The processor 101 of the system controller 5 saves an accumulated value of the drive time of the photoconductor drum 122 in the storage device 104 every time the photoconductor drum 122 is driven. When the accumulated value of the drive time of the photoconductor drum 122 reaches a predetermined drive time as the update condition, the processor 101 updates the reference target value to a corrected target value using the correction value corresponding to the predetermined drive time stored in the storage device 104. Note that the correction value can also be updated for the drive time of the developing device 110 or the drive time of the transfer belt 21 in the same manner as for the drive time of the photoconductor drum 122.

[0081] Moreover, when it is assumed that the state of the static elimination light changes according to the elapsed time, the digital multifunction machine 1 may set the elapsed time as an update condition for the correction value. The emission time of the static elimination light by the static eliminator 132 may be set as the elapsed time as an update condition for the correction value. For example, when the system controller 5 sets an update condition for the emission time of the static elimination light, the system controller 5 stores a correction value corresponding to a predetermined elapsed time as an update condition in the storage device 104. The processor 101 of the system controller 5 saves a cumulative value of the emission time of the static elimination light in the storage device 104 every time the static eliminator 132 emits the static elimination light. When the cumulative value of the emission time of the static elimination light reaches the predetermined elapsed time as an update condition, the processor 101 updates the reference target value to a corrected target value by using the correction value corresponding to the predetermined elapsed time stored in the storage device 104.

[0082] FIG. 11 is a flowchart for explaining the process of updating the correction value for the target value of the image stabilization control in the digital multifunction peripheral 1 as the image forming apparatus according to the embodiment. The processor 101 of the system controller 5 in the digital multifunction peripheral 1 accumulates log information indicating the degree of use or the elapsed time according to the execution of the image forming process in the storage device 104 (ACT111). For example, when a predetermined number of prints is set as the update condition, the processor 101 stores log information including the cumulative number of prints in the storage device 104. In addition, when the drive time (or elapsed time) of a specific unit is set as the update condition, the processor 101 stores log information including the cumulative drive time (or elapsed time) of the specific unit in the storage device 104.

[0083] Processor 101 determines whether the log information stored in storage device 104 has reached an update condition for the correction value for the target value of image stabilization control (ACT112). For example, if a predetermined number of prints is set as the update condition, processor 101 determines whether the cumulative number of prints stored in storage device 104 has reached the predetermined number of prints as the update condition. If a predetermined drive time is set as the update condition, processor 101 determines whether the cumulative drive time of a specific unit has reached the predetermined drive time as the update condition.

[0084] If the log information stored in the storage device 104 does not reach the update condition (ACT112, NO), the processor 101 returns to ACT111 and continues to accumulate the log information. When the information indicated by the log information stored in the storage device 104 reaches an update condition (ACT112, YES), the processor 101 updates the correction value for the reference target value of the image stabilization control to a correction value according to the update condition (ACT113). When updating the correction value, the processor 101 updates the target value for each toner to a target value obtained by correcting the reference target value with a correction value according to the update condition. For example, when the accumulated number of prints reaches a predetermined number of prints as the update condition, the processor 101 updates the correction value for the reference target value to a correction value according to the predetermined number of prints as the update condition. When the accumulated drive time of a specific unit reaches a predetermined drive time as the update condition, the processor 101 updates the correction value for the reference target value to a correction value according to the predetermined drive time.

[0085] As described above in detail, the image forming apparatus according to the embodiment has a toner sensor that outputs a signal corresponding to the amount of toner adhesion on the transfer belt. The image forming apparatus stores target values ​​including a correction value of image stabilization control for stabilizing an image in a memory for each type of toner. The image forming apparatus executes image stabilization control that adjusts the setting values ​​used in the image formation process so that the output value of the toner sensor becomes the target value including the correction value.

[0086] As a result, the image forming apparatus according to the embodiment can stabilize images without installing a light-shielding wall or the like for blocking the static elimination light emitted by the static eliminator. In other words, even if the image forming apparatus according to the embodiment is structured so that part of the static elimination light from the static eliminator is incident on the toner sensor in order to achieve size reduction and cost reduction, the image can be stabilized without adding any parts or the like.

[0087] Furthermore, the image forming apparatus according to the embodiment stores in the memory log information indicating the degree of use, the elapsed time, etc. The image forming apparatus updates a correction value for a target value of image stabilization control for stabilizing an image in accordance with the log information stored in the memory. This allows the image forming apparatus to update the correction value to one appropriate for the state when the state of the static elimination light changes depending on the cumulative number of prints, the driving time of a specific unit, or the elapsed time.

[0088] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0089] An image forming apparatus according to an embodiment will be described below. [1] The image forming apparatus A photoconductor; a static eliminator that emits static elimination light to be irradiated onto the photoconductor; a charger for charging the photoconductor discharged by the charger; an exposure unit for forming an electrostatic latent image on the photoreceptor charged by the charger; a developing unit that supplies toner to the photoconductor on which an electrostatic latent image has been formed by the exposure unit; a toner sensor that outputs a signal corresponding to an amount of toner attached to an image carrier to which the toner is transferred from the photoconductor; a memory for storing target values ​​including a correction value of image stabilization control for stabilizing an image for each type of toner; a processor that executes image stabilization control for setting an output value of the toner sensor to a target value including the correction value for each type of toner; has. [2] In the image forming apparatus according to [1], The correction value is a correction amount for each type of toner according to the wavelength of the static elimination light emitted by the static eliminator. [3] In the image forming apparatus according to [2], The correction value is a correction amount according to the sensor sensitivity of the toner sensor. [4] [2] In the image forming apparatus according to the present invention, the toner sensor has a light emitting element that irradiates a detection surface with light, a first light receiving element that receives specularly reflected light from the detection surface, and a second light receiving element that receives diffuse light from the detection surface; The memory stores, as the correction value, a correction amount for a specific color toner selected based on the spectral reflectance of each color of toner with respect to the wavelength of the static elimination light. [5] [4] In the image forming apparatus according to the present invention, The static eliminator emits static elimination light having a wavelength of 570 nm or more, The memory stores, as the correction values, a correction amount for yellow toner and a correction amount for magenta toner. [6] In the image forming apparatus according to [1], The processor updates the correction value stored in the memory in accordance with the number of recording media onto which the image forming apparatus has transferred the toner image from the image carrier. [7] In the image forming apparatus according to [1], The processor updates the correction value stored in the memory in accordance with the driving time of the photoconductor. [8] In the image forming apparatus according to [1], The processor updates the correction value stored in the memory in accordance with the driving time of the developing unit. [9] In the image forming apparatus according to [1], The processor updates the correction value stored in the memory in accordance with the driving time of the transfer body.

[10] In the image forming apparatus according to [1], The processor updates the correction value stored in the memory in accordance with the light emission time during which the static eliminator emits static elimination light. [Explanation of symbols]

[0090] 1...digital multifunction peripheral (image forming apparatus), 2...printer, 3...operation panel, 4...scanner, 5...system controller, 21...intermediate transfer belt (image carrier), 22...secondary transfer roller, 24...toner sensor, 100...exposure device, 101...processor, 104...storage device, 105...communication interface, 110...developer, 122...photosensitive drum, 126...charger, 128...primary transfer roller, 130...cleaner, 132...static eliminator.

Claims

1. A photoconductor; a static eliminator that emits static elimination light to be irradiated onto the photoconductor; a charger for charging the photoconductor discharged by the charger; an exposure unit for forming an electrostatic latent image on the photoreceptor charged by the charger; a developing unit that supplies toner to the photoconductor on which an electrostatic latent image has been formed by the exposure unit; a toner sensor that outputs a signal corresponding to an amount of toner attached to an image carrier to which the toner has been transferred from the photoconductor; a memory for storing target values ​​including a correction value of image stabilization control for stabilizing an image for each type of toner; a processor that executes image stabilization control for setting an output value of the toner sensor to a target value including the correction value for each type of toner; An image forming apparatus comprising:

2. the correction value is a correction amount for each type of toner according to the wavelength of the static elimination light emitted by the static eliminator; The image forming apparatus according to claim 1 .

3. the correction value is a correction amount according to the sensor sensitivity of the toner sensor; The image forming apparatus according to claim 2 .

4. the toner sensor has a light emitting element that irradiates a detection surface with light, a first light receiving element that receives specularly reflected light from the detection surface, and a second light receiving element that receives diffuse light from the detection surface; the memory stores, as the correction value, a correction amount for a toner of a specific color selected based on a spectral reflectance of each color of the toner with respect to a wavelength of the static electricity removing light; The image forming apparatus according to claim 2 .

5. The static eliminator emits static elimination light having a wavelength of 570 nm or more, the memory stores a correction amount for yellow toner and a correction amount for magenta toner as the correction value; The image forming apparatus according to claim 4 .

Images