JP2012256006A - Image forming apparatus, and toner supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of printed materials.SOLUTION: A toner consumption calculation unit 303 calculates toner consumption consumed by a developing unit for developing electrostatic latent images. A first supply determination unit 307 determines whether to supply toner to the developing unit depending on an amount of toner in the developing unit. A supply control unit 309 causes a supply unit to supply toner to the developing unit with a supply amount of toner, the amount that is the cumulative of toner consumption calculated in the duration from the start of the previous toner supply to the time when the first supply determination unit 307 determines to supply toner. A second supply determination unit 311 determines to supply toner to the developing unit when the cumulative of toner consumption calculated during the supply of toner to the developing unit is more than the supply amount of toner. The supply control unit 309 causes the supply unit to supply additional toner to the developing unit with the supply amount of toner, the amount that is the cumulative of toner consumption calculated during the supply of toner to the developing unit if the second supply determination unit 311 determines to supply toner.

Description

  The present invention relates to an image forming apparatus and a toner replenishing method.

  In an electrophotographic image forming apparatus, toner is supplied from a toner container to a developing unit, and the developing unit develops an electrostatic latent image on a photosensitive drum using toner in the developing unit to form a toner image.

  Since the deterioration state is different between the toner replenished from the toner container and the toner in the developing unit, the development process becomes unstable if the ratio is largely lost. As a result, for example, background stains (background fogging) and density fluctuations occur. For this reason, in such an image forming apparatus, the toner remaining amount in the developing unit is detected, and when the detected toner remaining amount falls below the threshold value, a predetermined amount of toner is supplied from the toner container to the developing unit, and then supplied from the toner container. The ratio of the toner to be developed and the toner in the developing unit is controlled to be constant (see, for example, Patent Document 1).

  However, in the conventional technology as described above, the printing operation and the toner replenishing operation are performed separately. For this reason, when the toner replenishing operation is executed, the printing operation is intermittent, and the productivity of printed matter is reduced. Further, since the printing operation is not normally executed during the detection of the remaining amount of toner, if the number of times of detection of the remaining amount of toner can be reduced, the productivity of printed matter can be expected.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus and a toner replenishing method capable of improving the productivity of printed matter.

  In order to solve the above-described problems and achieve the object, an image forming apparatus according to one aspect of the present invention includes a toner consumption amount calculation unit that calculates a toner consumption amount consumed from a developing unit by developing an electrostatic latent image. And a first replenishment determination for determining whether or not to replenish toner from the toner amount in the developing unit or a cumulative toner consumption calculated by the toner consumption calculating unit after the start of the previous toner replenishment And the cumulative toner consumption calculated by the toner consumption calculation unit from the start of the previous toner supply to the time when the first supply determination unit determines to replenish the toner. A replenishment control unit that replenishes toner from the developing unit to the developing unit, and a cumulative amount of toner consumption calculated by the toner consumption calculating unit during replenishment of toner to the developing unit is greater than or equal to the toner replenishment amount A second replenishment determining unit that determines that toner is replenished to the developing unit, and the replenishment control unit supplies the toner to the developing unit when the second replenishment determining unit determines to replenish the toner. The toner supply amount calculated by the toner consumption amount calculation unit during toner replenishment is used as the toner supply amount, and toner is further supplied from the supply unit to the developing unit.

  The toner supply method according to another aspect of the present invention includes a toner consumption calculation step in which the toner consumption calculation unit calculates a toner consumption consumed from the development unit by developing the electrostatic latent image; The replenishment determining unit determines whether or not to replenish toner to the developing unit based on the toner amount in the developing unit or the accumulation of the toner consumption calculated by the toner consumption calculating step after the start of the previous toner replenishment. 1 of the toner consumption amount calculated by the toner consumption amount calculation step between the first supply determination step and the supply control unit from the start of the previous toner supply until the first supply determination step determines that the toner is to be supplied. A first replenishment control step for replenishing toner from the replenishment unit to the developing unit using the accumulated toner replenishment amount and a second replenishment determining unit during toner replenishment to the developing unit A second replenishment determining step for determining that toner is replenished to the developing portion when the cumulative toner consumption amount calculated in the toner consumption amount calculating step is equal to or greater than the toner replenishment amount; 2 When it is determined that the toner is replenished in the replenishment determining step, the cumulative toner consumption calculated in the toner consumption calculating step during the toner replenishment to the developing unit is used as the toner replenishment amount from the replenishing unit. And a second replenishment control step for replenishing toner to the developing unit.

  According to the present invention, there is an effect that productivity of printed matter can be improved.

FIG. 1 is a mechanical configuration diagram illustrating an example of a printing apparatus according to the present embodiment. FIG. 2 is a mechanical configuration diagram illustrating an example of the developing device of the present embodiment. FIG. 3 is a diagram illustrating an example of the circulation unit of the present embodiment. FIG. 4 is a graph showing the relationship between the mixing ratio of the deteriorated toner and the undegraded toner and the background level. FIG. 5 is a block diagram illustrating an example of a hardware configuration of the printing apparatus according to the present embodiment. FIG. 6 is a block diagram illustrating an example of a functional configuration of the printing apparatus according to the present embodiment. FIG. 7 is a flowchart illustrating an example of toner supply processing of the printing apparatus according to the present exemplary embodiment.

  Hereinafter, embodiments of an image forming apparatus and a toner supply method according to the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the image forming apparatus of the present invention is an electrophotographic color printing apparatus, specifically, four colors of yellow (Y), magenta (M), cyan (C), and black (K). However, the present invention is not limited to this example. The image forming apparatus of the present invention can be applied to any color and monochrome as long as it is an apparatus that forms an image by an electrophotographic method. For example, an electrophotographic facsimile machine, a copying machine, and a multifunction peripheral (MFP) ) Etc. Note that a multifunction peripheral is a device having at least two functions among a printing function, a copying function, a scanner function, and a facsimile function.

  First, the configuration of the printing apparatus according to the present embodiment will be described.

  FIG. 1 is a mechanical configuration diagram illustrating an example of a printing apparatus 1 according to the present embodiment. As illustrated in FIG. 1, the printing apparatus 1 includes an image forming unit 10, an optical scanning unit 30, an intermediate transfer belt 40, support rollers 41 and 42, a paper feeding unit 50, a paper feeding roller 51, and a pad. 52, a transport roller pair 53, a secondary transfer roller 60, a fixing unit 70, a paper discharge roller pair 80, and a paper discharge table 81.

  The image forming unit 10 includes process cartridges 11Y, 11M, 11C, and 11K corresponding to yellow, magenta, cyan, and black, respectively. The process cartridges 11Y, 11M, 11C, and 11K have image forming portions 12Y, 12M, 12C, and 12K, respectively. As shown in FIG. 1, the moving direction of the intermediate transfer belt 40 (direction of arrow S) is as shown in FIG. From the upstream side, the image forming units 12Y, 12M, 12C, and 12K are arranged along the intermediate transfer belt 40 in this order. As described above, the printing apparatus 1 according to the present embodiment uses a so-called tandem method, but is not limited thereto.

  The image forming unit 12Y includes a photosensitive drum 13Y, a charging roller 14Y, a developing device 20Y, a primary transfer roller 15Y, and a cleaning device 16Y. The image forming unit 12Y and the optical scanning unit 30 perform an image forming process (a charging process, an exposure process, a developing process, a transfer process, and a cleaning process) on the photosensitive drum 13Y, so that a yellow color is formed on the photosensitive drum 13Y. A toner image is formed and transferred to the intermediate transfer belt 40.

  The image forming units 12M, 12C, and 12K all have the same components as the image forming unit 12Y, and the image forming unit 12M forms a magenta toner image by performing an image forming process. The image forming unit 12C forms a cyan toner image by performing an image forming process, and the image forming unit 12K forms a black toner image by performing an image forming process. Therefore, in the following, description will be made mainly on the components of the image forming unit 12Y, and the components of the image forming units 12M, 12C, and 12K will be denoted by Y attached to the reference numerals of the components of the image forming unit 12Y. Instead, only M, C, and K are attached, and the description thereof is omitted. In this embodiment, non-magnetic one-component toner is used as the toner, but the present invention is not limited to this.

  The photosensitive drum 13Y is an image carrier and is rotationally driven in the direction of arrow a by a photosensitive drum driving device (not shown).

  First, in the charging step, the charging roller 14Y in contact with the photosensitive drum 13Y initializes and charges the surface of the rotationally driven photosensitive drum 13Y uniformly at a high potential in the dark.

Then, in the exposure step, an optical scanning unit 30, yellow laser beam L _Y which is optically modulated on the charged surface of the photosensitive drum 13Y, the selectively exposed and scanned, the surface of the photosensitive drum 13Y based on the image data An electrostatic latent image corresponding to the color component image is formed. As a result, the laser beam L _Y at exposure scanned low potential portions electrostatic latent image potential on the surface portion of the photosensitive drum 13Y is attenuated (image portion), and a high laser beam L _Y does not change the potential not irradiated The potential part becomes the background part. The optical scanning unit 30 for the photosensitive drum 13M, exposed with the laser beam L _M corresponding to magenta, for the photosensitive drum 13C, exposed with laser light L _C that corresponds to the cyan photosensitive drum 13K for exposes a laser beam L _K corresponding to black.

  Subsequently, in the developing process, the developing device 20Y develops the electrostatic latent image formed on the photosensitive drum 13Y with yellow toner, and forms a yellow toner image on the photosensitive drum 13Y. Specifically, the developing device 20Y forms a yellow toner image on the photosensitive drum 13Y by transferring yellow toner to the low potential portion of the photosensitive drum 13Y to visualize the electrostatic latent image. To do. The developing device 20Y may transfer yellow toner to the high potential portion of the photosensitive drum 13Y to form a yellow toner image on the photosensitive drum 13Y.

  Subsequently, in the transfer process, the primary transfer roller 15Y transfers the yellow toner image formed on the photosensitive drum 13Y to the intermediate transfer belt 40. A small amount of untransferred toner remains on the photosensitive drum 13Y even after the toner image is transferred.

  Subsequently, in the cleaning process, the cleaning device 16Y wipes off the untransferred toner remaining on the photosensitive drum 13Y.

  The intermediate transfer belt 40 is an endless belt wound around a plurality of rollers such as support rollers 41 and 42, and moves endlessly in the arrow S direction when one of the support rollers 41 and 42 is driven to rotate. First, a yellow toner image is transferred to the intermediate transfer belt 40 by the image forming unit 12Y, then a magenta toner image by the image forming unit 12M, a cyan toner image by the image forming unit 12C, and the image forming unit 12K. Black toner images are sequentially superimposed and transferred. As a result, a full-color toner image is formed on the intermediate transfer belt 40.

  A plurality of recording sheets are accommodated in the sheet feeding unit 50 in an overlapping manner. The paper feed roller 51 is in contact with the recording paper located at the top of the paper supply unit 50 and feeds the recording paper in contact therewith. The pad 52 is separated into one recording sheet when a plurality of recording sheets are fed by the sheet feeding roller 51. The transport roller pair 53 transports the recording paper fed by the paper feed roller 51 between the support roller 41 and the secondary transfer roller 60 at a predetermined timing.

  The secondary transfer roller 60 collectively transfers the full-color toner image conveyed by the intermediate transfer belt 40 onto the recording paper conveyed by the conveyance roller pair 53.

  The fixing unit 70 fixes the full-color toner image on the recording paper by heating and pressing the recording paper on which the full-color toner image is transferred.

  The paper discharge roller pair 80 discharges the recording paper on which the full-color toner image is fixed by the fixing unit 70 to the paper discharge table 81.

  FIG. 2 is a mechanical configuration diagram illustrating an example of the developing device 20Y of the present embodiment. As shown in FIG. 2, the developing device 20Y includes a developing unit 21Y, a remaining amount sensor 22Y, and a toner container 23Y.

  The developing unit 21Y stores toner and develops the electrostatic latent image on the photosensitive drum 13Y using the stored toner. The developing unit 21Y includes a housing 210Y, a developing roller 211Y, a supply roller 212Y, A developing blade 213Y, a circulation unit (not shown), and transmission windows 215Ya and 215Yb are provided.

  The housing 210Y is a developing tank that stores toner used as a developer, and has an opening at the top.

  The developing roller 211Y is a toner carrier and rotates in the direction of arrow b in the developing process. Thereby, the electrostatic latent image on the photosensitive drum 13Y is visualized with toner. The developing roller 211Y has a metal core, and the outer periphery is made of conductive rubber (for example, conductive urethane rubber or silicone rubber) whose volume resistance value is adjusted to about 10E5 to 10E7Ω. In the present embodiment, the developing roller 211 has a rubber hardness Hs75, a core metal diameter φ6, and a rubber part outer diameter φ12, but is not limited thereto.

  The supply roller 212Y is a toner supply member, and is in contact with the developing roller 211Y so as to be rotatable. As the supply roller 212Y, for example, a sponge roller to which foamed polyurethane made semiconductive by mixing carbon on the outer periphery of a metal core is attached. In this embodiment, the supply roller 212Y has a core metal diameter of φ6 and a rubber part outer diameter of φ12, a nip with the developing roller 211Y is set to 2 mm, and a rotation speed ratio is set to 1. It is not limited to. For example, in this embodiment, the contact nip between the supply roller 212Y and the developing roller 211Y is set to about 1 to 3 mm, and the supply roller 212Y is rotated in the direction of the arrow c with respect to the developing roller 211Y. The function of efficiently transporting the toner inside the housing 210Y to the surface layer of the developing roller 211Y is obtained.

  The developing blade 213Y is in contact with the developing roller 211Y to control the toner layer thickness on the surface of the developing roller 211Y conveyed by the supply roller 212Y to a predetermined amount, and at the same time, removes the toner on the surface of the developing roller 211Y. Frictionally charged. In this embodiment, the developing blade 213Y is made of a SUS material having a plate thickness of 0.1 mm, a linear pressure of 45 N / m, a nip position of 0.2 mm from the tip, and a length from the support end to the free end (free length) ) Is set to 14 mm, but is not limited to this. For example, in this embodiment, the developing blade 213Y can be formed of a metal plate, the contact pressure of the developing blade 213Y with respect to the developing roller 211Y is a normal linear pressure of 20 to 60 N / m, and the contact nip position is 0 from the tip of the developing blade 213Y. By setting the thickness to about 5 ± 0.5 mm, a stable toner thin layer can be formed on the developing roller 211Y, but these values are matched to the characteristics of the toner used, the developing roller, the supply roller, etc. To be determined as appropriate.

  The circulation unit circulates the toner replenished from the toner container 23Y, and conveys the replenished toner to the supply roller 212Y via the toner detection position of the remaining amount sensor 22Y while stirring. FIG. 3 shows an example of the circulation unit. A circulation part is realizable by a screw member as shown in FIG. 3, for example. In the present embodiment, the stirring period of the circulation unit is 500 msec. Further, the process speed of the circulating portion corresponds to the peripheral speed of the photosensitive drum 13Y and is 150 mm / sec. Further, it is assumed that the toner conveyance speed at the process speed is 80 mm / sec. The distance from the toner supply position to the toner detection position of the remaining amount sensor 22Y is 200 mm. However, it is not limited to these. Note that the process speed and the toner conveyance speed are in a proportional relationship, and when the process speed is 200 mm / sec, the circulation unit conveys the toner replenished from the toner container 23Y to the toner detection position of the remaining amount sensor 22Y. It takes 1.8 seconds.

  The transmission windows 215Ya and 215Yb constitute a part of the side wall of the housing 210Y and are arranged to face each other.

  The remaining amount sensor 22Y is a sensor that detects the amount of toner stored in the developing unit 21Y, and a first sensor 220Y that detects that the amount of toner stored in the developing unit 21Y is the first threshold value. And a second sensor 221Y that detects that the amount of toner stored in the developing unit 21Y is a second threshold value smaller than the first threshold value.

  The first sensor 220Y includes a light emitting element 220Ya disposed above the transmission window 215Ya and a light receiving element 220Yb disposed above the transmission window 215Yb, and the second sensor 221Y is disposed below the transmission window 215Ya. The light emitting element 221Ya and the light receiving element 221Yb disposed below the transmission window 215Yb. The light emitting element 220Ya and the light receiving element 220Yb are arranged such that light generated from the light emitting element 220Ya passes through the transmission windows 215Ya and 215Yb and is received by the light receiving element 220Yb. The light emitting element 221Ya and the light receiving element 221Yb The light generated from the light passes through the transmission windows 215Ya and 215Yb and is received by the light receiving element 221Yb.

  When sufficient toner remains in the housing 210Y, light generated from the light emitting elements 220Ya and 221Ya is blocked by the toner inside the housing 210Y and does not reach the light receiving elements 220Yb and 221Yb. However, when the printing apparatus 1 repeats the printing operation and the consumption of the toner inside the housing 210Y proceeds, the draft surface of the toner inside the housing 210Y decreases, and first, the light generated from the light emitting element 220Ya reaches the light receiving element 220Yb. After that, the light generated from the light emitting element 221Ya also reaches (receives) the light receiving element 221Yb.

  In the present embodiment, the remaining amount of toner in the housing 210Y when the light generated from the light emitting element 220Ya reaches the light receiving element 220Yb is set as the first threshold, and the light generated from the light emitting element 221Ya. The remaining amount of toner in the housing 210Y at the time when the toner reaches the light receiving element 221Yb is set as the second threshold value. For this reason, in the present embodiment, it can be determined whether the remaining amount of toner in the housing 210Y has reached the first threshold value or whether it has reached the second threshold value based on the presence or absence of light detection of the light receiving elements 220Yb, 221Yb. .

  In the present embodiment, an example in which the remaining amount sensor 22Y is realized by an optical sensor has been described. However, the remaining amount sensor 22Y may be realized by a powder detection sensor using a piezoelectric vibration element. The powder detection sensor is capable of detecting the presence or absence of toner because the detection surface constantly vibrates and vibration is suppressed when the toner contacts the detection surface. If the remaining amount sensor 22Y is realized by an optical sensor, the cost can be reduced, and if the remaining amount sensor 22Y is realized by a powder detection sensor, the remaining amount of toner can be detected with high accuracy.

  The toner container 23Y (an example of a replenishing unit) is a container that contains toner to be replenished to the developing unit 21Y, and is detachably attached to the upper portion of the housing 210Y. The toner container 23Y includes an agitator 230Y and a toner supply roller 231Y.

  The agitator 230Y rotates in the direction of arrow e to loosen the toner inside the toner container 23Y. The agitator 230Y can be realized by, for example, a member in which a sheet-shaped honey is adhered to a rotating shaft. The agitator 230Y and the toner supply roller 231Y are driven in synchronization.

  The toner supply roller 231Y rotates to supply the toner contained in the toner container 23Y to the housing 210Y through an opening provided in the upper part of the housing 210Y of the developing unit 21Y. Here, the toner replenishment amount from the toner container 23Y to the developing unit 21Y is determined by the driving time of the toner replenishment roller 231Y. For example, in this embodiment, the toner supply roller 231Y is designed to supply 0.5 g of toner to the developing unit 21Y by one rotation, but the present invention is not limited to this. Therefore, the toner supply amount from the toner container 23Y to the developing unit 21Y can be controlled by controlling the drive time of the toner supply roller 231Y. If the drive time is lengthened, the toner supply amount increases, and if the drive time is shortened, the toner is charged. Replenishment amount decreases.

  When the rotation speed of the toner supply roller 231Y is variable, the toner supply amount can be controlled by changing the rotation speed even when the driving time of the toner supply roller 231Y is fixed. If the amount increases and the rotation speed decreases, the amount of toner replenishment decreases.

  Since the developing devices 20M, 20C, and 20K have the same components as the developing device 20Y except that the toner colors are different, detailed description thereof is omitted. However, in the following description, the constituent elements of the developing devices 20M, 20C, and 20K may appear by substituting the symbols Y of the constituent elements of the developing device 20Y with M, C, and K, respectively.

  FIG. 4 is a graph showing the relationship between the mixing ratio of the deteriorated toner and the undegraded toner and the background level. Here, the deteriorated toner refers to toner stored in the developing unit. The toner stored in the developing unit is subjected to physical stress as the developing unit is driven, and its characteristics are deteriorated as compared to a completely unused toner. . The undegraded toner refers to toner that is replenished from the toner container to the developing unit. The toner container is driven only when the toner is replenished, has few members that give stress to the contained toner, and has almost no deterioration in characteristics as compared with a completely unused toner. Called.

  The graph shown in FIG. 4 shows the result of mixing the deteriorated toner remaining inside the developing unit after printing durability and the undegraded toner contained in the toner container, filling the developing unit again, and measuring the background stain. Is shown. In the example shown in FIG. 4, a non-magnetic one-component toner is used, and as the deteriorated toner, a toner after a printing endurance time of 25 hours assuming deterioration due to a normal use state, and a state in which the deterioration level is further deteriorated. Two types of toner are used, which are toners after 50 hours of printing durability. The horizontal axis of the graph shown in FIG. 4 indicates the ratio of the deteriorated toner to the mixed toner obtained by mixing the deteriorated toner and the undegraded toner, and the vertical axis of the graph shown in FIG. The background level is shown when 1 is 1 (reference).

  From the graph shown in FIG. 4, the background level is best when only undegraded toner (100% undegraded toner) is used, and undegraded toner when only degraded toner (100% degraded toner) is used. It can be seen that the level of soiling is worse than that of using only the soil. This is because the deteriorated toner in the developing unit is continuously subjected to physical stress, and the external additive of the toner is peeled off or the toner itself is cracked. This is because the chargeability and fluidity) have changed (deteriorated). Specifically, the deteriorated toner in the developing unit is usually conveyed to the developing roller by the supply roller, and after the amount of adhesion on the developing roller is optimized by the developing blade, the developed toner is developed at the nip portion with the photosensitive member, and developed. The deteriorated toner that has not been used in the above process is repeatedly recovered by the supply roller, so that physical stress continues to be applied.

  Further, it can be seen from the graph shown in FIG. 4 that when the deteriorated toner and the undegraded toner are mixed, the background level is further deteriorated as compared with the case where only the deteriorated toner is used. This is because when the deteriorated toner and the undegraded toner are mixed, the toners interact with each other and the chargeability of the toner becomes more unstable.

  Here, since the ground level on the image that is acceptable for actual use is normally 0.97 or more, in order to maintain good image quality when assuming toner deterioration due to normal use conditions, mixing is required. The ratio of the deteriorated toner to the toner needs to be 78% or more or 35% or less. This is 22% or less or 65% or more in terms of the toner supply ratio from the toner container to the developing unit. The toner replenishment ratio refers to a ratio of toner (undegraded toner) replenished from the toner container to the developing unit by one replenishment and toner stored in the developing unit (deteriorated toner). Indicates the ratio of undegraded toner to degraded toner.

  If the toner replenishment ratio is 65% or more, the amount of toner replenishment from the toner container to the developing unit at one time increases, leading to an increase in the size of the developing device. In addition, if the amount of toner replenished at one time increases, development conditions that should be appropriately set, for example, development bias before and after the replenishment change greatly, and the image forming system becomes unstable. .

  On the other hand, when the toner replenishing ratio is 22% or less, the amount of toner replenished from the toner container to the developing unit at one time can be reduced, and the developing device can be downsized. Also, if the amount of toner replenished at one time is small, there is little fluctuation in the toner characteristics inside the developing unit before and after replenishment, so that the image forming system can be maintained stably.

  That is, a smaller toner replenishment ratio is preferable. When the deteriorated state of the deteriorated toner is further deteriorated (when the printing endurance time is 50 hours or more), the toner replenishment ratio that can tolerate the background level becomes a narrower region, so the toner replenishment ratio is less than 15%. It is desirable to make it.

  The toner used in the example shown in FIG. 4 has a volume average particle diameter of 8.5 μm, a polyester resin as a main component, and silica 1 with respect to 100 parts of a toner base prepared by mixing and crushing wax and pigment. This is manufactured by externally adding a part, and has almost the same characteristics as various toners used in general laser beam printers.

  In the example shown in FIG. 4, the non-magnetic one-component pulverized toner is used. However, the characteristics of the toner shown in FIG. 4 are general characteristics in the non-magnetic one-component toner. Shows the same characteristics. Even if the toner to be used is a magnetic one-component toner or a two-component toner, it is preferable that the amount of toner replenished at one time is small in order to suppress a change in toner characteristics before and after toner replenishment. Therefore, other toners may be used instead of the non-magnetic one-component pulverized toner, and the same effect as when the non-magnetic one-component pulverized toner is used can be obtained.

  FIG. 5 is a block diagram illustrating an example of a hardware configuration of the printing apparatus 1 according to the present embodiment. The printing apparatus 1 includes an operation panel I / F 101, an operation panel 103, NVRAM (Non Volatile Random Access Memory) 105Y, 105M, 105C, and 105K, an external I / F 107, an image processing IC 109, and an I / O 111. ROM (Read Only Memory) 113, RAM 115, and CPU (Central Processing Unit) 117, and these devices are connected to each other via a system bus 119. The printing apparatus 1 also includes electrical components such as remaining amount sensors 22Y, 22M, 22C, and 22K, a toner replenishment drive motor 123, and toner replenishment clutches 125Y, 125M, 125C, and 125K.

  In the following description, when it is not necessary to distinguish the developing portions of the respective colors, they may be simply referred to as the developing portions 21. When it is not necessary to distinguish the remaining amount sensors of the respective colors, they are simply referred to as the remaining amount sensor 22. When it is not necessary to distinguish the toner containers of the respective colors, the toner containers 23 may be simply referred to. When it is not necessary to distinguish the toner supply rollers of the respective colors, they are simply referred to as the toner supply rollers 231. If there is no need to distinguish between the toner replenishing clutches for each color, the toner replenishing clutch 125 may be simply referred to.

  The operation panel I / F 101 is an interface between the operation panel 103 and the system bus 119. The operation panel 103 inputs settings for various modes of the printing apparatus 1 to the CPU 117 via the operation panel I / F 101.

  The NVRAMs 105Y, 105M, 105C, and 105K are mounted in the toner containers 23Y, 23M, 23C, and 23K, respectively, and store cumulative toner consumption amounts of the developing units 21Y, 21M, 21C, and 21K, respectively.

  The external I / F 107 is a communication I / F with an external device (not shown) such as a host computer.

  The image processing IC 109 converts yellow, magenta, cyan, and black image data generated by a controller (not shown) into pixel image signals and inputs them to a pulse width modulation circuit (not shown). The pulse width modulation circuit supplies a laser drive pulse having a width (time length) corresponding to the level to the optical scanning unit 30 for each input pixel image signal. Thereby, the optical scanning unit 30 irradiates laser light of a color corresponding to the laser driving pulse for a time corresponding to the pulse width. That is, the laser light is driven for a longer time for a high density pixel and is driven for a shorter time for a low density pixel. For this reason, the image processing IC 109 counts the number of dots (number of pixels) of the obtained black, cyan, magenta, and yellow image data, thereby counting the video according to the image printing ratio of the electrostatic latent image of the corresponding color. Is calculated.

  The I / O 111 is an interface between the system bus 119 and electrical components such as the remaining amount sensors 22Y, 22M, 22C, and 22K, the toner supply driving motor 123, and the toner supply clutches 125Y, 125M, 125C, and 125K.

  The remaining amount sensors 22Y, 22M, 22C, and 22K are installed in the developing units 21Y, 21M, 21C, and 21K, respectively, and detect the remaining amount of toner stored in the installed developing unit 21.

  The toner supply drive motor 123 is a drive source for the toner supply rollers 231Y, 231M, 231C, and 231K. It is a driving source.

  The ROM 113 stores a control program executed by the CPU 117 and the like. The RAM 115 is used as a main memory and a work area of the CPU 117. Specifically, the RAM 115Y, 105M, 105C, and 105K and the data expansion area stored in the ROM 113 and the remaining amount sensors 22Y, 22M, 22C, And 22K are used as a temporary storage area for data detected by the 22K. The RAM 115 can be expanded in memory capacity by an optional RAM connected to an expansion port (not shown). The CPU 117 generally controls access to each device connected to the system bus 119 based on a control program stored in the ROM 113 and the like, and electrical components connected via the I / O 111. Controls input / output to and from. The CPU 117 communicates with an external device such as a host computer via the external I / F 107.

  FIG. 6 is a block diagram illustrating an example of a functional configuration of the printing apparatus 1 according to the present embodiment. The printing apparatus 1 includes a storage unit 301, a toner consumption calculation unit 303, a cumulative toner consumption calculation unit 305, a first supply determination unit 307, a supply control unit 309, and a second supply determination unit 311. Prepare. In the present embodiment, the storage unit 301 is realized by the NVRAMs 105Y, 105M, 105C, and 105K, the RAM 115, and the like, and includes a toner consumption calculation unit 303, a cumulative toner consumption calculation unit 305, a supply determination unit 307, and a supply control unit 309. The second supply determination unit 311 is realized by the CPU 117, but is not limited to this.

  The storage unit 301 stores a cumulative toner consumption amount of each color calculated by a cumulative toner consumption amount calculation unit 305 described later.

  The toner consumption calculation unit 303 calculates the toner consumption consumed by developing the electrostatic latent image. In this embodiment, the toner consumption calculation unit 303 develops the electrostatic latent image formed based on the image data from the number of dots (video count) of the yellow image data counted by the image processing IC 109. Thus, the toner consumption amount of yellow toner consumed from the developing unit 21Y is calculated. Similarly, the toner consumption amount calculation unit 303 uses the number of dots of the magenta image data to develop the electrostatic latent image formed based on the image data, and thereby consumes the magenta toner consumed from the development unit 21M. Calculate the amount. Similarly, the toner consumption calculation unit 303 uses the cyan toner data consumed from the developing unit 21C by developing the electrostatic latent image formed based on the number of dots of cyan image data. Calculate the amount. Similarly, the toner consumption amount calculation unit 303 uses the number of dots of the black image data to develop the electrostatic latent image formed based on the image data, and thereby consume the black toner consumed from the development unit 21K. Calculate the amount. In the present embodiment, 0.03 g / page of toner is consumed in the image printing ratio 2% chart, but the present invention is not limited to this. As described above, in the present embodiment, the toner consumption amount calculation unit 303 calculates the toner consumption amount from the number of dots (video count) of the image data, and thus can calculate the toner consumption amount with high accuracy.

  The cumulative toner consumption calculation unit 305 calculates the cumulative toner consumption by accumulating the toner consumption calculated by the toner consumption calculation unit 303 and stores it in the storage unit 301. Specifically, the cumulative toner consumption amount calculation unit 305 adds the toner consumption amount of each color calculated by the toner consumption amount calculation unit 303 to the cumulative toner consumption amount of the corresponding color stored in the storage unit 301. As a result, the accumulated toner consumption amount stored in the storage unit 301 is updated.

  Here, in the present embodiment, when it is determined by the first replenishment determining unit 307 described later that the developing unit 21 is replenished, and when the second replenishment determining unit 311 described later determines that the toner is replenished to the developing unit 21. In this case, the accumulated toner consumption amount of the corresponding color stored in the storage unit 301 is initialized. That is, the cumulative toner consumption calculation unit 305 calculates the cumulative toner consumption from the start of toner supply until the next toner supply is started.

  The first supply determination unit 307 determines whether or not to supply toner to the developing units 21Y, 21M, 21C, and 21K from the toner amounts in the developing units 21Y, 21M, 21C, and 21K, respectively. Specifically, the first supply determination unit 307 supplies toner to the developing unit 21 when the remaining amount sensor 22 installed in the developing unit 21 detects that the toner amount is equal to or less than a threshold value. If it is determined that the toner is not below the threshold, it is determined that toner is not supplied to the developing unit 21.

  Here, in this embodiment, since the toner in the developing unit 21 is circulated by the circulation unit (screw), the toner draft surface varies depending on the rotation angle of the circulation unit. In order to suppress the influence of the fluctuation of the toner draft surface, in the present embodiment, the remaining amount sensor 22 detects the amount of toner stored in the developing unit 21 for each stirring cycle of the circulation unit, and the first replenishment determining unit. In step 307, when the remaining amount sensor 22 detects that the toner amount has become equal to or less than the threshold value four times or more in five consecutive times, it determines that the toner is supplied to the developing unit 21.

  The first supply determination unit 307 determines whether or not to supply toner to the developing unit 21 when the developing unit 21 is not supplied with toner. In this embodiment, the case where the remaining amount sensor 22 detects that the toner amount is equal to or less than the threshold value is the case where the second sensor 221Y detects that the toner amount is equal to or less than the second threshold value. However, the present invention is not limited to this.

  Further, the first supply determining unit 307 determines whether or not to supply toner to the developing unit 21 when the supply to the developing unit 21 is completed and the second supply determining unit 311 determines that the toner is not supplied. Judging.

  The replenishment control unit 309 is calculated by the cumulative toner consumption calculation unit 305 from the start of the previous toner replenishment to the developing unit 21 until the first replenishment determining unit 307 determines to replenish the developing unit 21 with toner. The accumulated toner consumption amount of the color corresponding to the developed portion 21 is set as a toner replenishment amount. The replenishment control unit 309 replenishes the developing unit 21 with a toner replenishment amount from the corresponding toner container 23. Specifically, when the first supply determination unit 307 determines that the toner is supplied to the developing unit 21, the supply control unit 309 reads the accumulated toner consumption amount of the color corresponding to the developing unit 21 from the storage unit 301. . Then, the replenishment control unit 309 sets the read cumulative toner consumption amount as a toner replenishment amount, drives the toner replenishment drive motor 123 and the toner replenishment clutch 125 corresponding to the developing unit 21, and supplies a toner replenishment amount of toner to the corresponding toner container. 23, the developing unit 21 is replenished.

  When the second supply determination unit 311 determines that the developing unit 21 is to be supplied with toner, the supply control unit 309 performs the development calculated by the cumulative toner consumption calculation unit 305 during toner supply to the development unit 21. The cumulative amount of toner consumption for the color corresponding to the unit 21 is defined as a toner replenishment amount. The replenishment control unit 309 further replenishes the developing unit 21 with a toner replenishment amount from the corresponding toner container 23. Specifically, when the second supply determination unit 311 determines that the toner is supplied to the developing unit 21, the supply control unit 309 reads the accumulated toner consumption amount of the color corresponding to the developing unit 21 from the storage unit 301. . Then, the replenishment control unit 309 sets the read cumulative toner consumption amount as a toner replenishment amount, drives the toner replenishment drive motor 123 and the toner replenishment clutch 125 corresponding to the developing unit 21, and supplies a toner replenishment amount of toner to the corresponding toner container. 23, the developing unit 21 is replenished.

  The supply controller 309 can change the rotation speed of the toner supply roller 231 provided in the toner container 23. Thereby, the replenishment control unit 309 can change the replenishment time of toner from the toner container 23 to the corresponding developing unit 21.

  The second supply determination unit 311 determines that the cumulative toner consumption amount of the color corresponding to the developing unit 21 calculated by the cumulative toner consumption calculation unit 305 during the toner supply to the developing unit 21 is equal to or greater than the toner supply amount. Then, it is determined that the developing unit 21 is replenished with toner, and when it is less than the toner replenishment amount, it is determined that the developing unit 21 is not replenished with toner.

  Next, the operation of the printing apparatus according to the present embodiment will be described.

  In the following, it is assumed that the upper limit (first threshold) of the toner amount is 100 g, the lower limit (second threshold) of the toner amount is 90 g, and the remaining amount of toner stored in the developing unit 21 changes from 90 g to 100 g. . In this case, since the toner replenishment ratio is 10/90%, it is less than 15%.

  Although different depending on the configuration of the developing unit, in the general developing unit configuration as in this embodiment, in order to maintain a good image quality for an image with a high image printing ratio such as a solid image, the developing unit has It is necessary to leave 30 to 40 g or more of toner. In addition, it is necessary to consider the toner consumed until it is determined that the toner container is empty, the toner consumed after the toner container is empty and replaced with a new toner container, and the like. is there. For this reason, in the first embodiment, the numerical values as described above are set, but each numerical value is not limited to this and can be set as appropriate.

  FIG. 7 is a flowchart illustrating an example of toner supply processing of the printing apparatus 1 according to the present embodiment. In the example shown in FIG. 7, the toner replenishment process for yellow toner will be described, but the same process can be applied to the replenishment of cyan toner, magenta toner, and black toner.

  When the printing apparatus 1 starts printing, the optical scanning unit 30 starts exposure to the photosensitive drum 13Y and starts forming an electrostatic latent image based on the yellow image data of the print target page on the photosensitive drum 13Y. (Step S100).

  Subsequently, the toner consumption amount calculation unit 303 calculates the toner consumption amount from the number of dots of the yellow image data of the print target page (step S102).

  Subsequently, the cumulative toner consumption amount calculation unit 305 adds the toner consumption amount calculated by the toner consumption amount calculation unit 303 to the cumulative toner consumption amount of yellow (yellow image data) stored in the storage unit 301. Thus, the accumulated toner consumption amount stored in the storage unit 301 is updated (step S104).

  Subsequently, when the development unit 21Y finishes developing the electrostatic latent image based on the yellow image data of the print target page, the first supply determination unit 307 causes the remaining amount sensor 22Y to reduce the toner amount of yellow toner to a threshold value or less. It is confirmed whether or not it has been detected (step S106).

  If there is an amount of yellow toner that exceeds the threshold in the developing unit 21Y (Yes in step S106) and the next page is printed (Yes in step S108), the process returns to step S100, and the next page is printed. Further, when there is an amount of yellow toner exceeding the threshold in the developing unit 21Y (Yes in step S106), and the next page is not printed (No in step S108), the processing is ended.

  On the other hand, when there is no yellow toner exceeding the threshold in the developing unit 21Y (No in step S106), the replenishment control unit 309 reads the accumulated amount of yellow toner consumption from the storage unit 301 and substitutes it for the toner replenishment amount (step S106). S110).

  Subsequently, the replenishment control unit 309 initializes the accumulated amount of yellow toner stored in the storage unit 301 (step S112).

  Subsequently, the replenishment control unit 309 drives the toner replenishment drive motor 123 and the toner replenishment clutch 125Y to start the replenishment of yellow toner from the toner container 23Y to the developing unit 21Y (step S114).

  Subsequently, when there is a print request for the next page (Yes in step S116), the optical scanning unit 30 starts exposure to the photosensitive drum 13Y, and the yellow image of the next page to be printed on the photosensitive drum 13Y. Formation of an electrostatic latent image based on the data is started (step S118). If there is no print request for the next page (No in step S116), the process proceeds to step S124.

  Subsequently, the toner consumption amount calculation unit 303 calculates the toner consumption amount from the number of dots of the yellow image data of the next page to be printed (step S120).

  Subsequently, the cumulative toner consumption amount calculation unit 305 adds the toner consumption amount calculated by the toner consumption amount calculation unit 303 to the cumulative toner consumption amount of yellow (yellow image data) stored in the storage unit 301. Thus, the accumulated toner consumption amount stored in the storage unit 301 is updated (step S122).

  Subsequently, if the replenishment of yellow toner is not completed (No in step S124), the process returns to step S116. On the other hand, if the yellow toner supply is completed (Yes in step S124), the second supply determination unit 311 reads the accumulated cumulative toner consumption amount of yellow stored in the storage unit 301 and compares it with the toner supply amount. (Step S126). Thus, the second supply determination unit 311 determines whether the amount of toner consumed during toner supply is greater than the amount of toner supplied.

  Then, if the read yellow cumulative toner consumption amount is equal to or greater than the toner supply amount (Yes in step S126), that is, if the consumed toner amount is larger than the supplied toner amount, the process returns to step S110. As a result, the cumulative toner consumption calculated by the cumulative toner consumption calculation unit 305 during toner supply is substituted for the toner supply amount, and the toner supply amount of yellow toner is supplied continuously from the previous yellow toner supply. Done.

  On the other hand, if the read cumulative toner consumption amount of yellow is not equal to or greater than the toner replenishment amount (No in step S126), that is, if the consumed toner amount is not greater than the replenished toner amount, the process returns to step S106. Then, the first supply determining unit 307 determines whether or not there is an amount of yellow toner exceeding the threshold in the developing unit 21Y.

  As described above, according to the present embodiment, since printing of a page is executed even while toner is being replenished, it is possible to prevent the productivity of the printed matter from being lowered and to improve the productivity of the printed matter. In this embodiment, the toner remaining amount in the developing unit is estimated using the accumulated toner consumption amount and the toner replenishment amount during toner replenishment after completion of toner replenishment, and if necessary, toner replenishment is performed rather than detection of the toner remaining amount. Since priority is given, productivity of printed matter can be further improved.

  In particular, as in the present embodiment, when the toner in the developing unit is circulated by the circulation unit (screw), the toner draft surface fluctuates depending on the rotation angle of the circulation unit. In this case, it is necessary to detect the remaining amount of toner, and it takes time to detect the remaining amount of toner. For this reason, according to this embodiment, productivity of printed matter can be further improved.

(Modification)
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

  For example, in the above embodiment, the toner consumption amount calculation unit 303 calculates the toner consumption amount from the number of dots (video count) of the image data. However, if the print ratio of the image data can be acquired from the controller, the acquired print ratio The toner consumption amount may be calculated from the above. In this way, since the toner consumption amount can be calculated before development, it is possible to determine whether toner can be replenished before printing the image data of the page to be printed.

  Further, for example, in the above-described embodiment, the first supply determination unit 307 determines whether or not to supply toner to the developing unit 21 using the remaining amount sensor 22, but the cumulative toner consumption after the start of the previous toner supply. The determination may be made from the accumulation of toner consumption calculated by the amount calculation unit 305. Specifically, the threshold value is stored in the storage unit 301, and the first supply determination unit 307 stores the cumulative toner consumption amount calculated by the cumulative toner consumption amount calculation unit 305 after the start of the previous toner supply. Compared with the stored threshold value, it may be determined that the toner is supplied to the developing unit 21 when the threshold value is exceeded. By doing so, it is possible to further suppress a decrease in productivity of the printed matter.

  In this case, a plurality of threshold values are stored in the storage unit 301, and the first supply determination unit 307 uses the plurality of threshold values to determine stepwise whether to replenish toner, and the supply control unit 309 The toner may be replenished from the toner container 23 to the developing unit 21 in a replenishment time corresponding to the threshold used for the determination that the first replenishment determination unit 307 supplies the toner. In this way, toner can be replenished in a shorter cycle, leading to stable image quality.

  Further, as described above, in this embodiment, the replenishment time and the circulation time can be shortened by increasing the process linear speed during toner replenishment and toner circulation. For this reason, the printing apparatus 1 may increase the process line speed at the time of replenishment at a timing at which no image defect occurs even if the process line speed is increased, such as at the time of replenishment after printing.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 10 Image formation part 11Y, 11M, 11C, 11K Process cartridge 12Y, 12M, 12C, 12K Image formation part 13Y, 13M, 13C, 13K Photosensitive drum 14Y, 14M, 14C, 14K Charge roller 15Y, 15M, 15C, 15K Primary transfer roller 16Y, 16M, 16C, 16K Cleaning device 20Y, 20M, 20C, 20K Developing device 21Y Developing unit 22Y, 22M, 22C, 22K Remaining amount sensor 23Y Toner container 30 Optical scanning unit 40 Intermediate transfer belt 41, 42 Support Roller 50 Paper Feed Unit 51 Paper Feed Roller 52 Pad 53 Transport Roller Pair 60 Secondary Transfer Roller 70 Fixing Unit 80 Paper Discharge Roller Pair 81 Paper Discharge Stand 101 Operation Panel I / F
103 Operation panel 105K, 105C, 105M, 105Y NVRAM
107 External I / F
109 Image processing IC
111 I / O
113 ROM
115 RAM
117 CPU
119 System bus 123 Toner supply drive motor 125K, 125C, 125M, and 125Y Toner supply clutch 210Y Housing 211Y Developing roller 212Y Supply roller 213Y Developing blade 215Ya, 215Yb Transmission window 220Y First sensor 221Y Second sensor 220Ya, 221Ya Light emitting element 220Yb, 221Yb Light receiving element 230Y Agitator 231Y Toner supply roller 301 Storage unit 303 Toner consumption calculation unit 305 Cumulative toner consumption calculation unit 307 First supply determination unit 309 Supply control unit 311 Second supply determination unit

JP 2009-75574 A

Claims (10)

A toner consumption calculation unit for calculating a toner consumption amount consumed from the developing unit by developing the electrostatic latent image;
A first replenishment determining unit for determining whether or not to replenish toner from the toner amount in the developing unit or the accumulation of toner consumption calculated by the toner consumption calculating unit after the start of the previous toner replenishment; ,
The cumulative toner consumption calculated by the toner consumption calculation unit from the start of the previous toner supply to the time when the first supply determination unit determines that the toner is to be supplied is used as the toner supply amount. A replenishment control unit for replenishing toner to the developing unit;
A second replenishment determining unit that determines that toner is replenished to the developing unit when a cumulative amount of toner consumption calculated by the toner consumption calculating unit is greater than or equal to the toner replenishing amount during toner replenishment to the developing unit; With
When the second replenishment determining unit determines that the toner is to be replenished, the replenishment control unit calculates the cumulative amount of toner consumption calculated by the toner consumption amount calculating unit during toner replenishment to the developing unit. An image forming apparatus, wherein the toner is further replenished from the replenishing unit to the developing unit. The second supply determining unit does not supply toner to the developing unit when the cumulative toner consumption calculated by the toner consumption calculating unit is less than the toner supply amount during toner supply to the developing unit. Judging
The first supply determining unit determines whether or not to supply toner to the developing unit after completion of toner supply when the second supply determining unit determines not to supply toner. Item 2. The image forming apparatus according to Item 1.   The image forming apparatus according to claim 1, wherein the toner consumption amount calculation unit calculates a toner consumption amount from the number of dots or the printing rate of the image data from which the electrostatic latent image is generated. A detection unit for detecting that the amount of toner in the developing unit is equal to or less than a threshold;
The said 1st replenishment judgment part judges that the toner is replenished to the said developing part, when it is detected by the said detection part that it is below the said threshold value, The one of Claims 1-3 characterized by the above-mentioned. The image forming apparatus described in 1.   The image forming apparatus according to claim 4, wherein the detection unit detects that the toner amount of the developing unit is equal to or less than a threshold value using a light detection method or a powder detection method.   The first replenishment determining unit determines that toner is replenished to the developing unit when the cumulative toner consumption calculated by the toner consumption calculating unit exceeds a threshold after the start of the previous toner replenishment. The image forming apparatus according to claim 1. A plurality of the threshold values are set,
The replenishment control unit causes the replenishment unit to replenish the toner from the replenishment unit for a replenishment time corresponding to a threshold value used for determination of toner replenishment by the first replenishment determination unit. 6. The image forming apparatus according to 6.   The image forming apparatus according to claim 1, wherein the developing unit includes a circulation unit that circulates the toner replenished from the replenishing unit while stirring. The replenishment unit includes a replenishment roller,
9. The supply unit according to claim 1, wherein the supply control unit changes a toner supply time from the supply unit to the developing unit by changing a rotation speed of the supply roller. The image forming apparatus described. A toner consumption amount calculating unit for calculating a toner consumption amount consumed from the developing unit by developing the electrostatic latent image; and
The first replenishment determining unit determines whether or not to supply toner to the developing unit from the toner amount in the developing unit or the accumulation of the toner consumption calculated by the toner consumption calculating step after the start of the previous toner replenishment. A first replenishment determination step,
The cumulative toner consumption calculated by the toner consumption calculation step from the start of the previous toner supply to the time when it is determined to supply toner by the first supply determination step is used as the toner supply amount. A first supply control step for supplying toner from the supply unit to the developing unit;
The second replenishment determining unit determines to replenish toner to the developing unit when the cumulative amount of toner consumption calculated by the toner consumption calculating step is greater than or equal to the toner replenishment amount during toner replenishment to the developing unit. A second replenishment determination step,
When the replenishment control unit determines to replenish toner in the second replenishment determination step, the cumulative amount of toner consumption calculated by the toner consumption amount calculation step during toner replenishment to the developing unit is included in the toner replenishment step. A second replenishment control step for further replenishing toner from the replenishing unit to the developing unit as an amount;
And a toner replenishing method.

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