JPH09160364A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components, and to reduce cost, by detecting the number of writing pixels and estimating the toner consumption thereby performing toner replenishment without using a detecting sensor such as the toner density sensor. SOLUTION: In an image forming unit 1, the toner consumption after passing the maximum writing width L in a specified section of a developing sleeve 11 and a second agitating member 45 arranged close thereto, is estimated by calculating the number of pixels written in the specific section as a whole aerial integrated value of the image writing width L correspondingly to moving speed V2 of the developer, and multiplying this value P by the toner sticking quantity D with respect to laser beam spot diameter per one pixel, so that the toner quantity corresponding to the toner consumption is replenished in the timing matching with the toner being supported to the specified section where the toner is consumed. Counting and storing of the number of pixels, calculation of the toner consumption, the toner replenishment control corresponding to the toner consumption or the like is controlled by a control part of the image forming device body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to a two-component electrostatic latent image formed on an image bearing member, which is composed of a toner and a carrier. The present invention relates to an image forming apparatus which visualizes a toner image with a developing device using a system developer.

[0002]

2. Description of the Related Art After a photoconductor, which is an image carrier, is uniformly charged by a charging device, a document image is exposed on the photoconductor by an exposure device, or an image is written by a writing optical system using laser light. , An electrostatic latent image is formed, the electrostatic latent image is developed by a developing device to be visualized as a toner image, the toner image is transferred to a transfer material at a transfer portion, and the transfer material after the toner image transfer is performed. 2. Description of the Related Art An electrophotographic image forming apparatus that conveys a toner image to a transfer material by the fixing device to obtain a recorded image is known, and is applied to a copying machine, a printer, a facsimile, and the like.

In such an image forming apparatus, when a two-component developer composed of toner and carrier is used as the developer, only toner is consumed by image formation, so that the toner density in the developing apparatus is properly adjusted. Need to keep.
Therefore, the image forming apparatus using the two-component developer,
Usually, a sensor for detecting the toner density of the developer, a sensor for detecting the density of the toner image formed on the photosensitive member, and the like, when the sensor detects that the toner density is below the reference value, A toner replenishing mechanism that replenishes the toner from the toner container into the developing device based on the detection signal is provided. As an example, the carrier component in the developer is detected by a magnetic permeability measuring sensor, the toner replenishment is controlled so that the carrier component in the developer is constant, and thereby the toner concentration is controlled.

[0004]

In a conventional image forming apparatus using a two-component developer, the toner concentration in the developer is usually detected directly or indirectly by a sensor, and the toner is transferred from the toner container to the inside of the developing device. I was controlling the toner supply,
The use of a sensor for toner concentration detection is expensive, and the number of components such as the sensor, its mounting member, wiring, and detection circuit is also increasing.

Therefore, in the present invention, the function of a digital machine is utilized without using a detection sensor such as a toner density sensor, the number of pixels to be written is detected to estimate the toner consumption amount, and the toner is replenished correspondingly. It is an object of the present invention to provide an image forming apparatus capable of reducing the number of parts and costs.

[0006]

In order to achieve the above object, the present invention provides an image carrier on which an electrostatic latent image is formed, and a dot (pixel) of one dot formed by laser light on the image carrier. A writing optical system for forming an electrostatic latent image, and a electrostatic latent image formed on the image carrier by using a two-component developer composed of toner and carrier carried on a developing sleeve as a toner image visible image. The developing device is provided with first and second stirring members that are parallel to the developing sleeve axis, and the developer circulates in a loop by each stirring member and is close to the developing sleeve. (2) In the image forming apparatus including the developing device configured to convey the developer in the developing sleeve axial direction at the speed v _z , the writing optical system writes the developing sleeve and the second stirring member adjacent to the developing sleeve. Corresponds to width L A, it is divided into N blocks,
A unit for integrating and storing the number of written pixels for each L / N width in association with the moving speed v _z of the developer, and a toner per pixel for the number of pixels P integrated within the width L for each block A calculation means for multiplying the adhesion amount D to calculate a toner amount consumed for each block is provided, and a means for supplying the toner amount corresponding to the toner consumption amount to the L / N width is provided from the calculation result. It was configured. As a result, the conventional sensor for toner concentration detection can be eliminated.

Further, in the present invention, paying attention to the fact that the amount of toner adhered to the image bearing member varies depending on the environment (humidity), a humidity sensor is arranged in the vicinity of the developing device, and the humidity detected by this humidity sensor is adjusted. The corresponding toner adhesion amount D is provided with a control unit that is fed back to the calculation unit that calculates the previous toner consumption amount. As a result, the adhesion amount can be set for each environment, and the calculation accuracy of the toner consumption amount can be improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an example of the configuration and operation of the image forming system of the image forming apparatus in which the present invention is implemented will be described. FIG. 3 is a vertical sectional view of an image forming unit mounted on an image forming apparatus main body (not shown), and FIG. 4 is an external perspective view of the image forming unit. The image forming unit 1 is detachably attached to the main body of the image forming apparatus, and in this example, the image forming unit 1 is pushed by pushing the image forming unit in the direction shown by an arrow A in FIG. 3 is loaded and set at a predetermined position in the main body of the image forming apparatus shown in FIG.
By pulling out the image forming unit 1 in the opposite direction,
The image forming unit 1 can be taken out from the main body of the image forming apparatus. The image forming apparatus is configured as, for example, a copying machine, a printer, a facsimile or a composite machine thereof.

As shown in FIGS. 3 and 4, the image forming unit 1 has a unit case 2 and various image forming elements incorporated therein, which will be described later. The unit case 2 shown as an example in the drawings is A case body, a case cover 4 attached to the upper part thereof, a developing case cover 5 constituting an upper part of a developing device described later, an upper wall of a toner conveying path of the toner recycling device and an upper wall of the developing device, which are also described later. An upper cover 6 forming a part of the case cover 4, the case cover 4, the developing case cover 5, and the upper cover 6 are detachably locked to the case body 3 by a snap fit (so-called patching). Has been done. Development case cover 5
The opening 102 (FIG. 4) formed in the container is closed by an agent cartridge 81 (FIG. 3) not shown in FIG.

FIG. 5 is an external perspective view showing a state in which the case cover 4, the developing case cover 5, and the upper cover 6 shown in FIGS. 3 and 4 are removed from the case body 3, and FIG. 5 is a partial cross-sectional plan view in the same state as in FIG. Inside the unit case 2, a drum-shaped photoreceptor 7 which is an example of an image bearing member on which an electrostatic latent image is formed, and a charging roller 8 which is an example of a charging device are rotatably assembled. The charging roller 8 extends parallel to the photoconductor 7. In FIG. 5, the charging roller 8 is shown separated from the photoconductor 7.

During the image forming operation, the photosensitive member 7 is rotationally driven in the clockwise direction in FIG. 3 by a driving device (not shown), and at this time, a discharging light from a discharging device (not shown) supported by the main body of the image forming device. L1 is the case cover 4
The light enters the inside of the unit case 2 through the opening 34 formed in, and irradiates the surface of the photoconductor 7. As a result, the surface potential of the photoconductor 7 is averaged to a reference potential of, for example, 0 to -150V. On the other hand, the charging roller 8 is pressed against the surface of the photoconductor 7 and is rotated by the rotation of the photoconductor 7, while the photoconductor 7 has a surface potential of, for example, -1100.
It is uniformly charged to be around V. At this time, a predetermined voltage is applied to the charging roller 8 by a power source (not shown).

The light-modulated laser beam L2 is applied to the surface portion of the photoconductor 7 charged to a predetermined polarity as described above in the exposure section 9. The laser beam L2 is emitted from a writing optical system (not shown) supported by the main body of the image forming apparatus, and the opening 35 is formed in the case cover 4.
Is incident on the unit case 2 through. Then, an electrostatic latent image is formed on the photoconductor in units of one dot (pixel) by the laser light, and the image is written. For example, laser light L2
The surface potential of the photosensitive portion (image portion) irradiated with is 0 to -290 V, and the surface potential of the photosensitive portion (background portion) not irradiated with the laser beam L2 is -1100 described above.
Around V is maintained.

On the other hand, the unit case 2 rotatably supports the developing sleeve 11 (not shown in FIG. 5) of the developing device 10 as shown in FIGS. 3 and 6, and the developing sleeve 11 forms an image. During operation, it is driven to rotate counterclockwise in FIG. Further, a developing case 12 of the developing device 10 is constituted by a part of the case body 3 in the unit case 2 and the above-mentioned developing case cover 5 covering the upper part thereof, and a developer chamber 90 is defined therein. The developer chamber 90 of the developing case 12 contains a powdery two-component developer 101 (FIG. 3) having a toner and a carrier, and the inside of the developing sleeve 11 is generally indicated by reference numeral 13. A plurality of magnets are arranged immovably.

By rotating the developing sleeve 11 as described above, the developer 101 in the developing case 12 is carried while being carried on the developing sleeve 11 by the magnetic force of the magnet 13, and the developer regulating member including the doctor blade 14 is provided. The amount of developer transported is regulated by the. The regulated developer is carried to the developing area between the developing sleeve 11 and the photoconductor 7, and at this time, for example, −80 in the developing sleeve 11.
Since the developing bias voltage of about 0 V is applied, the toner in the developer conveyed to the developing area is electrostatically transferred to and adheres to the image portion on the photoconductor 7, and the predetermined amount on the photoconductor 7. Toner image is formed. That is, the electrostatic latent image formed on the photoconductor 7 is visualized as a toner image.

As described above, the developing device 10 visualizes the electrostatic latent image formed on the image carrier composed of the photoconductor 7 as a toner image by using the two-component developer 101 having toner and carrier. The developing sleeve 11 serves as an example of a developer carrying member for carrying and carrying the two-component developer 101 to be developed.

On the other hand, as shown in FIG. 3, a transfer roller 15, which is an example of a transfer device, is rotatably supported by the main body of the image forming apparatus so as to face the photoconductor 7. Further, a sheet feeding device (not shown) is provided on the image forming apparatus main body side, and a transfer sheet 100, which is an example of the transfer material, is provided from the sheet feeding device as shown by an arrow B in FIG. , 24 and the left and right guides 27 provided at the position of the maximum paper width, the transfer unit 2 between the photoconductor 7 and the transfer roller 15 is guided.
It is transported to 2. In the transfer paper 100, the transfer unit 2 between the photoconductor 7 and the transfer roller 15 is in a state where the front end of the transfer paper 100 is aligned with the front end of the toner image formed on the photoconductor 7.
Pass 2 At this time, the transfer roller 15 moves the transfer paper 1
3 rotates counterclockwise in FIG. 3 while contacting the photoconductor 7 via 00, and since the transfer bias voltage is applied to the transfer roller 15, the toner image on the photoconductor 7 is transferred onto the transfer paper 100. Transcribed.

The transfer sheet 100 separated from the photoconductor 7 is conveyed to a fixing device (not shown) as indicated by an arrow B1 in FIG. 3, where a toner image is transferred by the action of heat and pressure. It is fused and fixed on 100. A charge eliminating needle 16 supported by the image forming apparatus main body is arranged on the downstream side of the transfer unit 22 in the transfer direction of the transfer paper 100. The static elimination needle 16 is made of a thin metal plate extending parallel to the photoconductor 7, and the portion of the static elimination needle 16 on the side facing the photoconductor 7 is formed in a sawtooth shape, and the tip of each tooth is sharpened. . A voltage is applied to the static elimination needle 16 by a power source (not shown), whereby the transfer paper 100 is neutralized and the transfer paper 100 is easily separated from the photoconductor 7.

It should be noted that an intermediate transfer member is used as the transfer material, the toner image on the photosensitive member is primarily transferred to the intermediate transfer member, and then the toner image is secondarily transferred to the transfer paper which is the final transfer material. It can also be configured to.

After the toner image is transferred, the residual toner adhering to the photoconductor 7 is scraped off from the surface of the photoconductor 7 by the cleaning blade 18 of the cleaning device 17 shown in FIG. In this way, the surface of the photoconductor 7 is cleaned and the next image forming operation starts again. Cleaning device 1
7 has a cleaning case 19 formed by a part of the case body 3 in the unit case 2, and the toner scraped off by the cleaning blade 18 is
The toner carrying member 20 disposed in the cleaning case 19 is discharged to the outside of the cleaning device 17 and reused in the developing device 10 as described later. The toner carrying member 20 is configured in an appropriate form such as a toner carrying screw or a toner carrying coil. The cleaning blade 18 is an example of a cleaning member that removes toner remaining on the surface of the photoconductor 7 from the surface and cleans the surface, and is fixedly held by the case body 3.

As described above, the illustrated image forming apparatus includes:
The toner image formed on the image carrier composed of the photoconductor 7 is transferred onto the transfer paper 100 conveyed toward the image carrier to obtain a recorded image, and the main body of the image forming apparatus is configured. The detachably mounted image forming unit 1 is one in which at least one of the image forming elements including the above-mentioned image carrier is assembled in a unit case, and in the illustrated example, the photoconductor 7, the charging roller 8, The image forming unit 1 is configured by assembling the respective components of the developing device 10 and the cleaning device 17 into the unit case 2.

Next, each component of the image forming unit will be described. As the photoconductor 7 which is an image carrier, for example, S
An inorganic photoconductor such as e or an organic photoconductor (OPC) using an organic material formed on a drum-shaped conductive substrate is used. Here, as an example, the photoconductor 7 is composed of a laminated OPC photoconductor, and the laminated OPC photoconductor has a charge generation layer (CGL) having a thickness of 0.1 to 1 μm on its conductive substrate and 10 to 10 μm. A charge transfer layer (CTL) having a thickness of 30 μm is sequentially laminated, and the charge generation layer and the charge transfer layer form a photosensitive layer.

Next, the charging roller 8 shown in FIG. 3 and FIG.
Is an example of a charging device that charges the photoconductor 7 so as to form an electrostatic latent image on the photoconductor 7 as an image carrier. The charging roller 8 is an outer periphery of a metal cored bar. It has a structure in which a conductive rubber is wrapped around the surface, and contacts the surface of the photoconductor 7 only when the photoconductor 7 is charged. The charging roller 8 has only one end in each longitudinal direction in FIG.
Are rotatably supported by the bearings 33a shown in FIG. 1, and each of the bearings 33a is attached to the photoreceptor 7 together with the charging roller 8 at each end of the charging roller case 33 extending in parallel with the charging roller 8 in the longitudinal direction. It is supported so as to be movable within a predetermined range in the direction of approaching or separating. On the surface of the charging roller case 33 facing the charging roller 8, a cleaning pad 32 which is an example of a charging roller cleaning member extending along the charging roller 8 is attached.

A first compression spring (not shown) is brought into pressure contact between each of the bearings 33a described above and each end of the charging roller case 33 in the longitudinal direction.
3a is pressed toward the photoconductor 7 so that the charging roller 8 can be pressed against the surface of the photoconductor 7. Further, the charging roller case 33 is also formed in the case main body 3 of the unit case 2 so that each end of the case 33 in the longitudinal direction is movable in a direction of approaching or leaving a predetermined range with respect to the surface of the photoconductor 7. Each notch 36 (only one is shown in FIG. 5) is assembled. Such charging roller case 33
The case cover 4 (FIGS. 3 and 4) prevents the case from coming out of the case body 3. Further, a second compression spring 37 (only one of which is shown in FIG. 5) different from the above-mentioned first compression spring is provided between the case body 3 and each longitudinal end portion of the charging roller case 33. The charging roller case 33 is pressure-loaded and is biased in the direction away from the surface of the photoconductor 7.

The case cover 4 serves as a protective cover for preventing the human body from touching the photoconductor 7, the charging roller 8 and the like. In addition, as described above, the second compression spring 37 is used. The charging roller case 33, which is biased by, also functions as a stopper that prevents the charging roller case 33 from coming off the case body 3. Accordingly, it is not necessary to provide an independent stopper member for the charging roller case 33, and the simplification of the configuration can be achieved.

On the other hand, as shown in FIG. 3, the main body of the image forming apparatus is provided with an electromagnetic clutch 39 for controlling the rotation of the cam 38. The cam 38 is fixed to the rotary shaft of the electromagnetic clutch 39. Is configured to rotate 120 ° in one operation. In addition, this cam 38
One end 41a of a swing arm 41, which is swingably supported by the image forming apparatus main body via a pivot pin 40, comes into pressure contact with the action of a spring (not shown), and the other end 41b of this arm 41 is attached to the case cover 4. Charging roller case 33 through the opening 34
Is in contact with the upper surface of the The upper surface of the charging roller case 33 is in pressure contact with the other end 41b of the swing arm 41 by the pressing action of the second compression spring 37 described above.

When the cam 38 occupies the rotational position shown in FIG. 3 and the cam surface portion indicated by the symbol a _{1 is in contact} with the one end 41a of the swing arm 41, the charging roller case 33 is also shown in FIG. However, at this time, the charging roller 8 is pressed against the surface of the photoconductor 7 by the pressing action of the first compression spring, and the voltage applied to the core of the charging roller 8 causes As described above, the photoconductor 7 is charged to a predetermined polarity.

As described above, since the charging roller 8 is continuously in contact with the surface of the photoconductor 7 during the charging operation for charging the photoconductor 7, the fine toner adhering to the photoconductor 7 stains the charging roller 8. Therefore, uneven charging may occur on the photoconductor 7. Therefore, in the image forming apparatus of this example, the electromagnetic clutch 39 is activated to rotate the cam 38 by 120 ° at an appropriate time other than the charging operation by the charging roller 8, and the cam surface portion indicated by reference numeral a ₂ in FIG. Comes into pressure contact with one end 41 a of the swing arm 41. As a result, the other end 41b of the swing arm 41 pressurizes and moves the charging roller case 33 in a direction approaching the surface of the photoconductor 7. At this time, the charging roller 8 is still in pressure contact with the surface of the photoconductor 7, and therefore the cleaning pad 32 is in pressure contact with the peripheral surface of the charging roller 8. At that time, the charging roller 8 rotates following the rotation of the photoconductor 7, and the cleaning pad 32 cleans the peripheral surface of the charging roller 8. In this way, it is possible to prevent the charging operation of the photoconductor 7 from being performed while the charging roller 8 is soiled by the toner, and to prevent uneven charging of the photoconductor 7.

When the operation of the image forming apparatus is stopped,
By the operation of the electromagnetic clutch 39, the surface of the cam 38 indicated by reference numeral a ₃ in FIG. 3 is brought into pressure contact with the one end 41 a of the swing arm 41. As a result, the other end 41b of the swing arm 41 is lifted above the state shown in FIG.
3 moves in a direction away from the photoconductor 7 by the action of the second compression spring 37 described above. As a result, the charging roller 8 also separates from the surface of the photoconductor 7. If the charging roller 8 is kept in contact with the photoconductor 7 for a long time while the image forming apparatus is not operating, the photoconductor 7 may be contaminated and an abnormal image may be generated. In the device,
As described above, when the operation is stopped, the charging roller 8 is separated from the photoconductor 7 to prevent the abnormal image from being generated during the image forming operation.

A charging device comprising a corona discharger may be used in place of the charging roller 8. In this case, since the corona discharger is installed in non-contact with the photoconductor, the above-mentioned charging roller contact is made. The separation mechanism is not required, and the number of parts can be reduced. However, the corona discharger has a problem of ozone generation, and when the charging roller 8 is adopted as in this example, the ozone generation amount when the corona discharger is used can be suppressed to 1/100 to 1/1000. This makes it unnecessary to attach an ozone processing member to the main body of the image forming apparatus.

As a charging control method by the charging roller 8, either a constant voltage control method or a constant current control method can be adopted. In this example, the applied voltage correction for the resistance fluctuation of the charging roller 8 is required, but the constant voltage control method is adopted. As the temperature detecting means for the charging roller 8, as shown in FIG. 3, a thermistor 43 mounted on the case cover 4 is used. The thermistor 43 detects the surface temperature of the charging roller 8 and sends a signal to a circuit for correcting the applied voltage corresponding to the change in temperature of the charging roller 8 and the change in its electric resistance. The thermistor 43 is provided at a position in contact with the charging roller 8 when the charging roller 8 is separated from the surface of the photoconductor 7.

Next, the developing device 10 will be described. As described above with reference to FIGS. 3, 5, and 6, the developing case 12 contains the two-component developer 101 having a carrier and a toner, which are made of, for example, small iron balls. Reference numeral 101 denotes a developing chamber 9 of the developing case 12 by means of first and second stirring members 44 and 45 which will be described in detail later.
It is agitated while being circulated and conveyed in a loop shape in 0, and is supplied to the developing sleeve 11. As described above, the layer thickness of the developer supplied to the developing sleeve 11 is regulated by the doctor blade 14 provided around the developing sleeve 11. A portion of the peripheral surface of the developing sleeve 11 facing the photoconductor 7 is exposed to the outside from the developing case 12.

Here, the developing sleeve 11 is made of a non-magnetic cylindrical body made of aluminum having an outer diameter of, for example, 16 to 20 mm, and its peripheral surface is formed smoothly or in order to enhance the developer carrying property. An unevenness such as a V groove is formed on the outer peripheral surface of the developing sleeve 11.

As shown in FIG. 6, a shaft 46 penetrates the inside of the developing sleeve 11, and the magnet 13 is fixed to the shaft 46. An end portion 46a on the front side of the shaft 46 is fixed and supported to the case body 3 of the unit case 2 as described later, and an end portion 46b on the rear side is fitted and fixed to the rear side end of the developing sleeve 11. It is fitted to the sleeve end member 47 via a bearing so as to be relatively rotatable. The shaft portion 47a of the sleeve end member 47 is rotatably supported by the case body 3 of the unit case as described later. The front end of the developing sleeve 11 is rotatably supported by the shaft 46 via a bearing. The "back side" and "front side" referred to here are based on the attachment / detachment direction of the image forming unit 1 to / from the image forming apparatus main body.

As described above, the shaft 46 is fixedly supported together with the magnet 13 with respect to the unit case 2, and the shaft 4 is fixed.
A developing sleeve 11 is rotatably supported by the roller 6. Then, the sleeve end member 47 is rotationally driven via a coupling 48 attached to the sleeve end member 47 and a coupling 49 (FIG. 4) on the side of the image forming apparatus main body that engages with the sleeve end member 47, so that the developing sleeve 11 can be rotated. It is rotationally driven in the counterclockwise direction in 3. The bias voltage to the developing sleeve 11 is applied from the image forming apparatus main body side via the couplings 48 and 49 described above.

FIG. 7 is an explanatory view showing the relationship between the developing sleeve 11, the magnet 13 arranged inside the developing sleeve 11 so as not to rotate, and the photosensitive member 7. As shown here, the individual magnets of the magnet 13, namely the first to fifth magnets 13a to 13
Reference characters e are arranged in the circumferential direction of the developing sleeve 11 and fixed to the shafts 46, respectively, and extend in the longitudinal direction of the sleeve 11. And these magnets 13a to 13e
Thus, magnetic force distributions P _{1 to} P _{6 in the} normal direction are formed in the circumferential direction of the developing sleeve 11.

The first magnet 13a substantially faces the photoconductor 7 and its magnetic force distribution has a peak above the line connecting the centers of the photoconductor 7 and the developing sleeve 11 by θ = 3 ° to 10 °. doing. The peak magnetic flux density is 80-100
(MT (millitesla)). If the peak magnetic flux density is too low, the carrier of the developer cannot be held on the developing sleeve 11 and the developer scatters. On the other hand, if the size is too large, the toner developed on the photoconductor 7 is likely to have a trace of the ears in the circumferential direction, and the toner attached to the low potential portion of the photoconductor 7 is collected again in the developing sleeve 11. Sometimes. On the other hand, if the angle θ is too large, the developing ability will decrease.

The magnetic force distribution P ₂ by the second magnet 13b is
It has a peak magnetic flux density of 50 to 80 (mT) near the opening of the developing case 12. This magnetic force has a function of carrying the developer into the developing case 12 and also carrying the air near the lower side of the developing case 12 into the developing case 12. As a result, it is possible to prevent the toner from scattering outside the developing case 12. In order to improve the efficiency of air transportability, the shape of the developing case portion 12a corresponding to the peak magnetic flux density portion may be slightly expanded in the direction away from the developing sleeve 11.
This makes it possible to smoothly form the ears of the developer.

The third magnet 13c forms a magnetic field distribution P _3, conveys the developer to the developing case 12 by the magnetic force, in cooperation with the fourth magnet 13d, force distribution P
₄ (magnetic flux density of 10 mT or less) is formed. As a result, the developer that has been used for development is separated from the developing sleeve 11.

The magnetic force of the fourth magnet 13d serves to hold the developer supplied by the second stirring member 45 (FIG. 6), which will be described in detail later, on the developing sleeve 11. By reducing the magnetic flux density in the region of the doctor blade 14 and allowing the developer to pass in a state of being in close contact with the developing sleeve 11, the layer thickness of the developer can be regulated stably.

The fifth magnet 13e forms a magnetic force distribution P ₆ and carries the developer held by the magnetic force of the fourth magnet 13d to the region of the first magnet 13a, but stabilizes the developer and In order to control the air flow around the developing sleeve 11, the peak magnetic flux density of the magnetic force distribution P ₆ is set so that the inlet seal 50, which will be described later, comes into contact with the developer.

Gap between the developing sleeve 11 and the photoconductor 7
Is the gap Gd between the developing sleeve 11 and the doctor blade 14.
And Gp = Gd × (0.8 to 1.0), Gp−Gd = (0 to 0.
15) Value that satisfies mm.

The peripheral speed of the developing sleeve 11 is set to vs (mm / se
c), where the peripheral speed of the photoconductor 7 is vp (mm / sec), the relationship between them is as follows. vs = (1 to 2.5) × vp

As shown in FIGS. 6 and 8, the shaft portion 47a of the sleeve end member 47 projecting from the rear end portion of the developing sleeve 11 is rotatably fitted to the rear support member 57, and the shaft 4
The front end portion 46a of 6 is fitted in the front support member 58 in a relatively non-rotatable manner. These support members 57 and 58 are
As shown in FIG. 8, the doctor blade 14 is connected by a screw 59 which is inserted into the long holes formed in these and screwed into the doctor blade 14. Therefore, by loosening these screws 59, the position of the doctor blade 14 can be adjusted with respect to the developing sleeve 11 in the direction substantially normal thereto. After the adjustment, the screw 59 is tightened to fix the doctor blade 14 to the developing sleeve 11. The value obtained by moving the doctor blade 14 with respect to the developing sleeve 11 as described above and the gap between the two correspond one-to-one. In addition, such adjustment work is performed by the doctor blade 1
4 and the developing sleeve 11 can be easily performed with the developing device removed from the developing device.

As shown in FIGS. 5 and 6, the case body 3 of the unit case 2 has a front outer plate 51 on its front side.
And a front side inner plate 52, and a back side outer plate 53 and a back side inner plate 54 on the back side thereof. Inner plates 5 of case body 3
The lower edges of the front and rear side plates of the developing case cover 5 (FIGS. 3 and 4) are in contact with the upper edges of the second and the second side plates 54, respectively. The front and rear side plates of the entire developing case 12 are constituted by. As described above, the developing case 12 containing the two-component developer is formed by a part of the unit case 2. Regarding the front and rear side plates of the developing case cover 5, only the inner side thereof is shown with reference numeral 5a in FIG.

In the photoconductor 7, the flange members 86 and 87 fixed to the respective longitudinal end portions of the photoconductor 7 have the positioning plate 5 on the front side.
A rear inner plate 52 and a rear outer plate 53 of the case main body are rotatably supported via a rear plate 5 and a rear positioning plate 56, respectively. The front support member 58 fitted to the front end portion 46a of the shaft 46 is also non-rotatably supported by the front inner plate 52 of the unit case 2 via the front positioning plate 55. Further, the shaft portion 47 a of the sleeve end member 47 is also rotatably supported by the back side outer plate 53 of the unit case 2 via the back side positioning plate 56. Back side support member 57
Is detachably fitted into the concave groove of the inner plate 54 on the back side.

As described above, the photoconductor 7 and the developing sleeve 1
1 is a positioning plate 5 whose front side and back side are common to each other.
It is supported by the unit case via 5, 56, whereby the center distance between the developing sleeve 11 and the photoconductor 7 is kept constant, and the gap Gp between them is always kept constant.

Further, as shown in FIG. 8, an inlet seal cover 60 is engaged with each of the support members 57 and 58 on the back side and the front side, and this cover 60 is also shown in FIGS. 3 and 7. As shown, the above-mentioned inlet seal 50 is attached. The inlet seal cover 60 is, as shown in FIG.
1 is located on the upstream side of the developing area between the photosensitive member 7 and the photoconductor 7 and covers the upper portion of the developing sleeve 11 to regulate the developer on the developing sleeve and regulate the air flow. The inlet seal 50 is made of, for example, a thin resin such as PET or PUR, and prevents the toner from scattering outside the developing device 10.

Further, as shown in FIG. 8, side seals 61 and 62 made of thin resin or the like are attached to the support members 57 and 58 on the back side and the front side, respectively, and these side seals 61 and 62 are developed. The sleeve 11 faces the peripheral surface of each end of the sleeve 11 in the longitudinal direction, and prevents the toner and the carrier from scattering from each end.

Next, the first and second stirring members 4 described above
As shown in FIG. 6, the shafts 4, 45 are composed of shafts 63, 64 and a plurality of elliptical plates 65, 66 fixed to the shafts 63, 64, respectively. Although the oval plates are not shown in FIG. 5 for the sake of clarity, the oval plates 65 and 66 are each formed by cutting out an ellipse. Incidentally, instead of the elliptical plate, the screw is used for each shaft 63,
Alternatively, the stirring members 44 and 45 may be fixed to 64.

The first stirring member 44 is rotatably supported at its longitudinal end portions of the shaft 63 by the front side support wall 67 and the rear inner plate 54 of the case body 3 of the unit case 2, Further, the shaft 64 of the second stirring member 45 has its longitudinal end portions at the front inner plate 52 of the unit case 2.
And the inner plate 54 on the back side are rotatably supported via bearings. Further, drive gears 68 and 69 are provided at the rear end portions of the shafts 63 and 64 of the stirring members 44 and 45, respectively.
A drive gear 70 is fixed to the sleeve end member 47 so as not to rotate relative to the respective shafts. These gears 70, 69, 68 mesh with each other via an intermediate gear (not shown).

Further, in the case main body 3 constituting the developing case 12, a partition wall 71 extending parallel to the stirring members 44, 45 stands in the area between the first and second stirring members 44, 45. The partition wall 71 is provided with notches on the front side and the back side, and passages 71a and 71b are formed therein.

As described above, when the sleeve end member 47 is rotationally driven by the drive unit on the image forming apparatus main body side, the developing sleeve 11 is rotated and the rotation of the sleeve end member 47 is driven by the drive gears 70, 69, 68. Is transmitted to the first and second stirring members 44 and 45 via the intermediate gear, and these members are rotationally driven in predetermined directions. As a result, the developer accommodated in the developer chamber 90 in the developing case 12 is conveyed while being stirred in the direction of the arrow X, and the developer is guided by the partition wall 71, and the passages 71a and 71b at both ends thereof are guided. Circulate through. As a result, the toner of the developer and the carrier are triboelectrically charged with different polarities. The developer is supplied to the developing sleeve 11, and the developer from the developing sleeve 11 is returned to the stirring member side. Since each of the elliptical plates 65 and 66 has a shape in which a part of an ellipse is cut out, the developer is agitated by hitting the edge of the cutout with the developer.

Here, when the pitch of the elliptical plates 65 and 66 in each stirring member 44 and 45 is P and the minor axis of the elliptical shape is Y, P = (1/3 to 4/5) × Y is satisfied. Is desirable. If the pitch P is smaller than this, the carrying force of the developer decreases, so the stirring member 4
The number of rotations of 4, 45 increases, and the developer is likely to deteriorate. If the pitch P is larger than the above formula, the stirring performance with respect to the developer deteriorates.

The first and second stirring members 44 and 45 have the same rotation speed, and the elliptical plates 65 and 66 have the same outer diameter Y and the same pitch P. In addition, the respective elliptical plates 65, 6
It is desirable that the relationship between the peripheral speed v in the short diameter portion of 6 and the peripheral speed vs of the developing sleeve 11 satisfy the following: vs = (1.1 to 1.5) × v.

If the peripheral speed v of the elliptical plates 65 and 66 is higher than that expressed by the above equation, the stress on the developer becomes large, and conversely, if it is low, the developer on the developing sleeve 11 is replaced. It takes a lot of time, and uneven density occurs in the toner image formed on the photoconductor 7.

Elliptical plates 65, 66 of the stirring members 44, 45
And the partition wall 71 or the developing case wall have a gap of 0.
It is desirable to set it to 5 to 2 mm. If this gap is larger than this value, the developer cannot be reliably conveyed and the developer that remains is generated, and if the gap is narrower than the above value, the developer will not adhere to the partition wall 71 or the development case wall. It may be rubbed excessively and deteriorate early.

When the gap between the elliptical plate 66 of the second stirring member 45 and the developing sleeve 11 is set to 1.5 to 3 mm, the developer can be smoothly supplied to the developing sleeve 11 and the developing sleeve can be developed. The developer can be smoothly collected from the sleeve 11. If the gap between the two is too large, the developer is not sufficiently supplied to and collected from the developing sleeve 11. On the contrary, if it is too small, the developer is deteriorated due to stress and uneven toner supply occurs.

3 and 6, the developing case 12 is provided with a sensor for detecting the toner concentration of the developer 101, for example, a magnetic permeability measuring sensor 72. In the present invention, as will be described in the embodiments described later, the function of a digital machine is utilized without using a detection sensor such as a toner density sensor, the number of written pixels is detected, and the toner consumption amount is estimated. A means for replenishing toner is provided, but here, for comparison with the present invention, an example of a toner replenishing operation based on a detection signal from a normal toner concentration sensor will be described.

As shown in FIGS. 3 and 4, a toner bottle 73 for replenishing toner is detachably attached to the main body of the image forming apparatus. When the sensor 72 detects that the toner concentration of the developer 101 accommodated in the developer chamber 90 in the developing case 12 is below the reference value, the toner replenishment signal based on the detection signal causes the toner bottle 73
Is rotatably driven via the drive shaft 74, whereby the toner is supplied from the replenishment port 73a of the toner bottle 73,
A toner replenishing portion 75 formed by the case body 3 through the opening 6a (FIG. 4) formed in the upper wall of the upper cover 6.
(FIGS. 5 and 6).

Toner bottle 73 containing replenishment toner
Has a spiral protrusion formed on its inner wall surface, and by its rotation, the toner inside is sequentially sent from the back side to the replenishment port 73a on the front side, and is replenished to the toner replenishing section 75. At this time, a hopper (not shown) for guiding the replenishment toner is provided between the toner bottle 73 and the toner replenishment section 75, whereby the toner from the toner bottle 73 does not scatter to the toner replenishment section 75. Supplied. Toner bottle 7
An electromagnetic clutch (not shown) is provided on the drive shaft 74 that rotates 3 and when the toner replenishment signal is output, the electromagnetic clutch is turned on and the drive shaft 74 for the toner bottle is turned on.
Rotates.

As shown in FIGS. 5 and 6, a thin resin sheet having a large number of small holes is formed between the toner replenishing section 75 and the developer chamber 90 containing the two-component developer. A shielding plate 76 is arranged, and a toner feeding member 78 made of a thin resin sheet having a base end fixed to a shaft 77 is arranged in the toner replenishing unit 75. The gear 79 fixed to the shaft 77 is The gear 80 fixed to the shaft 63 of the first stirring member 44 is meshed with the gear 80. The diameter of the small hole formed in the shielding plate 76 is, for example, about 0.5 to 1 mm. The shaft 77 is rotatably supported by the case body 3.

When the first stirring member 44 rotates as described above, the rotation is transmitted to the shaft 77 via the gears 80 and 79, the toner feeding member 78 rotates, and the tip portion thereof slides on the shield plate 76. Contact. As a result, the toner replenishing unit 75
Toner is sent into the developer chamber 90 provided with the first stirring member 44 through the small hole of the shielding plate 76.

As described above, the toner from the toner bottle 73 is temporarily accumulated in the toner replenishing section 75 and is sent to the developer chamber 90 little by little through the small hole of the shielding plate 76, so that the toner from the toner bottle 73 is definite amount by a certain amount. Even if the developer is not discharged, the developer chamber 90 is replenished with toner in a constant amount. The toner supplied to the developer chamber 90 is stirred and mixed by the stirring members 44 and 45 with the two-component developer existing therein.

If the sensor 72 continues to detect a decrease in toner concentration even after the above-described toner replenishing operation is performed, it is determined that the toner in the toner bottle 73 has run out, and the control unit (not shown) of the image forming apparatus. Displays that the toner end is near on a display unit (not shown) on the operation panel and informs the user of that fact. When the toner bottle is not replaced despite such a display, the operation of the image forming apparatus is stopped when 50 sheets of image forming operation are performed on A4 size transfer paper after the display. To do.

The control unit of the image forming apparatus uses the toner bottle 7
The replacement operation of No. 3 is judged by the opening / closing time of the front door (not shown) of the main body of the image forming apparatus, and after the replacement of the toner bottle 73, the toner replenishing operation is performed for a certain period of time, and the detection voltage of the sensor 72 reaches a certain value. After confirming this, the operation prohibition of the image forming apparatus is released.

As shown in FIG. 4, the developing case cover 5
An opening 102 is formed in the opening 102, and the developer cartridge 81 shown in FIG. 3 is mounted in the opening 102. When a new image forming unit 1 is shipped from a manufacturing factory or a store, the lower opening of the developer cartridge 81 is covered with a flexible sealing member (not shown), and toner and carrier are stored inside the cartridge 81. The two-component developer which it has is accommodated. At this time, no developer exists in the developer chamber 90.

When the image forming unit 1 is delivered to the user, by rotating a roller (not shown),
The seal member is wound around the roller to open the opening of the developer cartridge 81. As a result, the developer inside thereof falls into the developer chamber 90 inside the developing case 12.
As described above, since the developer is sealed and stored in the developer cartridge 81 until the image forming unit 1 is delivered to the user, deterioration of the developer due to moisture absorption during storage of the image forming unit 1 is prevented. It is also possible to prevent the developer from leaking from the developing device.

Next, the transfer device will be described. The transfer roller 15 shown in FIG. 3 is formed by winding a conductive resin around a metal cored bar and is pressed together with the bearing toward the photoreceptor by a compression spring (not shown). A constant current is passed through the transfer roller 15 to transfer the toner on the photoconductor onto the transfer paper. This transfer roller 15 is also the charging roller 8.
It is possible to make contact and separation with the photoconductor 7 by a contact and separation mechanism similar to.

Next, the cleaning device 17 shown in FIG.
Will be described. The cleaning blade 18 of the cleaning device 17 is made of a flat plate-like elastic material such as polyurethane rubber, and is fixed to a metal blade holder 82 with an adhesive or a double-sided tape. The blade holder 82 is
As shown in FIG. 5, the two positioning pins 83 provided on the inclined surface 84 formed on the case body 3 regulate the position in the direction parallel to the inclined surface 84, and the photoconductor 7
It is fixed to the case main body 3 with a screw 85 in a so-called counter direction that faces the rotation direction of the. This screw 85
Is in the same direction as the attachment surface of the cleaning blade 18, and the blade holder 82 is completely brought into close contact with the inclined surface 84 formed on the case body 3, and the inclined surface 84
The position of the cleaning blade 18 in the direction perpendicular to the inclined surface 84 is regulated.

As described above, the contact angle and pressure of the cleaning blade 18 with respect to the photosensitive member 7 are completely guaranteed, and problems such as defective cleaning and abnormal noise are prevented. Further, the position of the screw 85 for fixing the blade holder 82 to the case body 3 in the thrust direction can be set further outside the both ends of the photosensitive member 7 including the flange members 86 and 87. The advantage that only the cleaning blade can be replaced without removing 7 is obtained.

Next, the toner recycling device will be described. The toner scraped from the photoconductor 7 by the cleaning blade 18 of the cleaning device 17 shown in FIGS. 3 and 5 is conveyed to the front side in the cleaning case 19 by the toner conveying member 20 and is projected integrally with the case 19. It is discharged to the outside through the provided pipe 88. A gear (not shown) is fixed to the rear end of the toner conveying member 20, and this gear meshes with a gear integrally formed with the flange member 87 on the rear side of the photoconductor 7 to rotate the photoconductor 7. Is transmitted to the toner conveying member 20, and the toner conveying member 20 is rotationally driven.

As shown in FIGS. 5, 9 and 10, a roller portion 91 and a pair of pins 89 projecting from the roller portion 91 are provided at the front end of the toner conveying member 20 protruding outside the cleaning case 19. The toner recycling belt 92 is wound around the roller portion 91. A large number of long holes 93 of equal length are formed in the belt 92 along the circumferential direction at equal pitches, and the pins 89 described above are inserted into any of the long holes 93. As shown in FIG. 5, the toner recycling belt 92 is located in the toner transport path inside the trough-shaped portion 94 formed by a part of the case body 3, and the upper portion of this toner transport path is the upper cover 6 (see FIG. Four
(See also).

As shown in FIGS. 5 and 10, the trough-shaped portion 94
A driven roller 95 is rotatably supported by the roller, and the toner recycling belt 92 is wound around the roller 95. When the toner conveying member 20 is rotationally driven as described above, the roller portion 91 integrated with the toner conveying member 20 is rotated, and at this time, each pin 89 causes the elongated hole 93 of the toner recycling belt 92.
The toner recycle belt 92 is driven in the direction shown by the arrow in FIG.
In addition, a large number of elastic fins 96 arranged in the circumferential direction of the toner recycling belt 92 are provided on the outer surface of the toner recycling belt 92.
6 slidably contacts the gutter-shaped portion 94 and the inner wall surface of the upper cover 6.

The toner discharged by the toner conveying member 20 to the outside of the cleaning case 19 of the cleaning device 17 moves in an unstable manner in the vicinity of the transfer portion between the toner recycle belt 92 and the long hole 9 of the belt 92.
3 and falls on the inner wall surface of the trough 94. Then, the elastic fins 96 of the driven toner recycle belt 92 convey the toner in the toner conveying path, and the developing device 10
Is sent to the developer chamber 90. At this time, since the elastic fins 96 are pressed against the inner wall surface of the trough-shaped portion 94, the toner is not completely left behind and conveyed toward the developing device 10, and it is possible to prevent the toner from being excessively stressed.

Further, the gutter-shaped portion 94 near the driven roller 95.
A slanting surface 94a is formed on the inner wall surface of the slanted surface by a projection. When each elastic fin 96 rubs against the slanting surface 94a, the elastic fin 96 is elastically bent and deformed, so that the slanting surface 94a.
After passing a, each elastic fin 96 vigorously returns to the natural state. Therefore, the elastic fins 96
The toner conveyed by is blown to the first stirring member 44 shown in FIG. In this way, the toner can be reliably conveyed to the developer chamber 90. The toner conveyed to the developer chamber 90 is agitated and mixed with the developer 101 present therein, and is reused.

As shown in FIG. 9, when the thickness of the toner recycling belt 92 is t ₁ and the thickness of each elastic fin 96 integrated with the toner recycling belt 92 is t ₂ , t ₁ <t ₂ is set. As a result, the waist strength of the elastic fins 96 becomes stronger than the waist strength of the toner recycling belt 92, and as shown in FIG. 10, the elastic fins 96 are pressed against the inner wall surface of the trough-shaped portion 94 to transfer the toner. The elastic fins 96 themselves are not largely bent and deformed during transportation. When the elastic fins 96 start to contact the inclined surface 94a, the elastic fins 96 are largely bent and deformed, and when the elastic fins 96 are elastically restored, the toner is vigorously ejected.

By using the toner recycling device as described above, the waste toner tank for storing the toner collected from the photoconductor 7 can be abolished, and the collected toner is collected by the developing device 1.
At 0, it can be reused efficiently.

Further, the gutter-shaped portion 94 which constitutes the toner conveying path.
Is composed of a part of the case body 3,
As in the case where the trough-shaped portion 94 and the other case body portion are separately configured, it is possible to prevent the problem that the toner leaks from the gap between them, and a sealing material such as sponge for preventing the toner leak is provided. There is no need to provide it. Further, since the gutter-shaped portion 94 and the other case body portion are integrated, the assembling property of the image forming unit 1 is improved.

Although an example of the configuration and operation of the image forming system of the image forming apparatus according to the present invention has been described above, the present invention uses the toner density detecting sensor 72 shown in FIGS. 3 and 6. It is an object of the present invention to provide an image forming apparatus that can utilize the function of a digital machine, detect the number of written pixels, estimate the toner consumption amount, and replenish toner accordingly.

That is, in the present invention, in the image forming apparatus having the structure shown in FIGS. 3 to 10, instead of the structure in which the toner is replenished based on the signal from the toner density sensor or the like, the developing sleeve 11 and the first sleeve adjacent thereto are replaced. 2 of the stirring member 45,
The width corresponding to the writing width L by the writing optical system is set to N
A unit for dividing and dividing the number of written pixels for each L / N width in association with the moving speed v _z of the developer in the axial direction of the developing sleeve, and a width L for each block.
The calculation unit has a calculation unit for calculating the toner amount consumed for each block by multiplying the number P of pixels accumulated in the above by the toner adhesion amount D per pixel, and the calculation result corresponds to the toner consumption amount. A means for replenishing the toner amount to the L / N width is provided. As a result, the toner concentration detecting sensor 72 shown in FIGS. 3 and 6 can be eliminated.

Further, in the present invention, paying attention to the fact that the amount of toner adhered to the photoconductor 7 varies depending on the environment (humidity), a humidity sensor is arranged in the vicinity of the developing device 10 of the image forming unit 1, and the humidity sensor detects the humidity. The toner adhesion amount D corresponding to the determined humidity is configured to include a control unit that is fed back to the calculation unit that calculates the previous toner consumption amount.

[0082]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing an embodiment of the present invention and is a partial cross-sectional plan view of an image forming unit of an image forming apparatus, which is a diagram corresponding to FIG. 6 described above. The configuration and operation of the image forming unit 1 of this embodiment are the same as those shown in FIGS. 3 to 10 except that the toner density detecting sensor 72 and the case for covering the sensor portion shown in FIGS. 3 and 6 are omitted. The configuration and operation of the image forming unit shown are similar to those described above.

Particularly important components in the image forming apparatus of the present invention are a writing system and a developing device.
This is to use a writing system that creates an electrostatic latent image on the photoconductor 7 at one dot point (pixel) by laser light. As such a writing system, although not shown, an optical writing optical system in which a semiconductor laser light source is combined with a deflector such as a rotating polygon mirror and a constant velocity scanning imaging optical system such as an fθ lens is used. The body 7 is irradiated with a laser beam as a minute spot, and the maximum writing width L is set in the axial direction of the photoconductor 7.
By performing optical modulation in accordance with an image signal while scanning at a constant speed in the range of, an electrostatic latent image is formed on the photoconductor 7 in units of one dot point (pixel), and an image is written. Developing device 1
Regarding No. 0, as shown in FIG. 1, the two-component developer including the toner and the carrier, in which the first and second stirring members 44 and 45 are arranged in parallel with the axis of the developing sleeve 11, Circulates in the developer chamber 90 in a counterclockwise loop shape as indicated by an arrow X, and the second agitating member 45 causes the developer to flow from the upper side (back side of the image forming unit) to the lower side (working side). The toner is replenished (new toner is replenished from the toner replenishing unit 75 or the toner replenishing unit 7) at the place 71a where the developer is conveyed to the front side of the image unit and delivers the developer to the first stirring member 44.
5 and replenishment of new toner + recycled toner by the toner recycling device).

In the present invention, in the image forming unit 1 having the structure shown in FIG. 1, as described above, the maximum writing width (in the drawing, the writing width) of the developing sleeve 11 and the second stirring member 45 adjacent to the developing sleeve 11 is fixed. L) The amount of toner consumed after passing is calculated as an integrated value in the entire area of the image writing width L while the number of pixels written in this fixed section is made to correspond to the moving speed v _z of the developer, and this value P is obtained. It is estimated by multiplying the toner adhesion amount D with respect to the laser beam spot diameter per pixel, and the toner amount according to the toner consumption amount is replenished at the timing when the toner is supplied to the certain section where the toner is consumed. To do. That is, in the image forming apparatus of the present invention, with the above configuration, the pixels are stored in time series, and the total number of pixels after passing the image writing width L is multiplied by the toner adhesion amount per pixel to calculate the toner consumption amount in a certain section. And a means for replenishing the toner amount corresponding to the toner consumption amount to the predetermined section.

The counting and storage of the number of pixels, the calculation of the toner consumption amount, the control of the toner replenishment corresponding to the toner consumption amount, and the like are specifically performed by the control unit of the main body of the image forming apparatus. Although not shown, the control unit is a well-known microcomputer, memory (RAM,
ROM), a counter circuit, a clock circuit, various control circuits, etc., and controls each component of the image forming apparatus such as an image forming unit according to the input information from the operation unit and the signals from various sensors, The image forming process, the toner replenishment control, and various arithmetic processes are performed.

The method of calculating the toner consumption amount and the method of replenishing the toner will be described in more detail below. As shown in FIG. 2, the developing width (L) corresponding to the maximum writing width L is shown in FIG.
Is divided into N blocks. While making the number of written pixels for each L / N width correspond to the moving speed v _z of the developer,
It is calculated as an integrated value in the entire image writing width L. More specifically, the number of pixels is calculated by monitoring the image signal sent to the drive circuit of the laser light source by the control unit and correlating the number of written pixels for each L / N width with the moving speed v _z of the developer. At the same time, it is taken into the memory and is calculated as an integrated value in the entire image writing width L by the calculation processor.

Now, the range of the writing time for counting the writing pixels of each block t seconds after the start is
For the block 1 on the right side of the L width in FIG. 2, from αt seconds to α
During t + β seconds, the nth block n is αt + (n−
1) × β seconds to αt + n × β seconds. Where α = v _z / v _L (v _z : developer transport speed,
v _L : laser writing speed), β = L / N. While doing so, the number of write pixels for each moving position of each block position is counted with the elapse of time t, and the pixels are stored in the storage means (memory) in time series, and the total number of pixels P for the L width is integrated. To do. After that, as described above, the total pixel number P is multiplied by the toner adhesion amount D per pixel (a value that has been experimentally obtained in advance and is stored in the memory) to calculate the toner consumption amount, that is, the toner amount. Replenishment amount V _H
Is calculated. V _H = P × D Then, the control unit controls the toner replenishment unit 75 to supply the toner amount actually consumed for each area of the developer according to the calculated toner replenishment amount V _H. . still,
The toner replenishing operation by the toner replenishing unit 75 is as described above.

With the above-mentioned structure, the toner amount actually consumed can be supplied to each area of the developer in the developing device 10, so that the toner density sensor can be eliminated. The number of parts can be reduced and cost can be reduced. Further, since the toner consumption amount of each block can be detected, even if a document having a biased image ratio (a document having a high image ratio on one side) is copied, a large amount of toner can be supplied to a place that consumes a large amount of toner. Further, the developer density can be made uniform, and the occurrence of background stains due to excessive toner replenishment, and conversely, reduction in image density due to insufficient toner replenishment can be prevented.

Regarding the toner end detection control, the internal capacity of the toner bottle is stored in the memory in advance, and when a new toner bottle is set, the total toner consumption amount stored in the nonvolatile memory is reset. And then
The amount of toner consumed from the time of setting the new toner bottle (obtained by the above method) is integrated and stored in the non-volatile memory. Then, when the total toner consumption amount reaches a predetermined consumption amount, it is displayed on the display panel of the operation unit that the toner end is near, and when the total toner consumption amount reaches the internal capacity of the toner bottle. The machine operation is stopped and the toner end is displayed on the display panel of the operation unit.

By the way, in the above system, the toner recycling was not taken into consideration, but the image forming unit 1 of the embodiment shown in FIG. 1 is equipped with the above-mentioned toner recycling system. In such a case, the amount of recycled toner may be calculated, and a value obtained by subtracting the amount of recycled toner from the amount of consumed toner may be used as the amount of toner supplied from the toner supply unit 75.

First, as the method of calculating the amount of recycled toner, the number of pixels of L width is counted for a certain period of time (Tsec), the total number of pixels in this period is S, and the average amount of recycled toner per unit time is V _R. When, in the formula _{V R = S × D × (} 1- transcription factor / 100) / T (g / sec), is determined recycled toner amount V _R. As described above, in the image forming apparatus of the present invention, in the above, means for counting and storing the number of L-width pixels for T time, and the average recycled toner amount per unit time are calculated and calculated from the result. The control unit is provided with a means for doing so.

As described above, in this example, the number of pixels is counted for a certain period of time, and this is divided by time to be averaged, so that the average recycled toner amount V _R is calculated. Then, the control unit, this value V _R, the above-described toner supply amount V
A value obtained by converting _H = P × D into a replenishment amount per unit time, or an amount subtracted from P × D / (L / Nv _z ) (g / sec) is controlled so as to be replenished from the toner replenishing unit 75. _{That, V H '= P × D} / (L / Nv z) By replenishing the amount of toner -V _R, the amount of toner to consumed by L / N intervals, the same sums as recycled toner amount As a result, excessive toner supply can be prevented, and problems such as scumming can be prevented. As described above, in the image forming apparatus of the present invention, the control section is provided with the arithmetic processing means for calculating the above-mentioned proper toner supply amount.

Further, the toner adhesion amount per pixel described above varies depending on the environment and particularly depends on humidity. That is, low humidity is low and high humidity is high. Therefore, in the present invention, the humidity sensor (not shown) is installed near the developing device 10 of the image forming apparatus, and the adhesion amount table for each humidity is stored in the storage unit (memory of the control unit). Then, the control unit detects the humidity by the humidity sensor, obtains the adhesion amount D corresponding to the humidity from the table, and feeds back the toner adhesion amount corresponding to the humidity to the calculation unit for calculating the previous toner consumption amount. To control. Then, by substituting it into D of the above formula for calculating the toner consumption amount (toner replenishment amount), the proper toner replenishment amount is calculated, and proper toner replenishment can be performed without being affected by humidity.

[0094]

As described above, in the image forming apparatus according to the first aspect of the present invention, the function of the digital machine is utilized to detect the number of writing pixels to estimate the toner consumption amount, and to replenish the toner accordingly. Therefore, the detection sensor such as the toner concentration sensor can be eliminated, and the number of parts and the cost can be reduced.

Further, in the image forming apparatus according to claim 2,
A humidity sensor is arranged in the vicinity of the developing device, and the toner adhesion amount corresponding to the humidity detected by the humidity sensor is provided with a control unit that feeds back to the calculation unit that calculates the toner consumption amount. Even if the toner adhesion amount changes due to the change, the toner consumption amount is calculated based on the corresponding adhesion amount, so the toner concentration does not become excessive or insufficient depending on the environment, and a constant value is set. Can be kept.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and is a partial cross-sectional plan view of an image forming unit of an image forming apparatus.

FIG. 2 is an explanatory diagram of a method of integrating the number of written pixels according to the present invention.

FIG. 3 is a diagram illustrating a configuration example of an image forming apparatus in which the present invention is implemented, and is a vertical cross-sectional view of an image forming unit mounted in an image forming apparatus main body.

FIG. 4 is a schematic external perspective view showing an image forming unit to which a developer cartridge is not mounted and a toner bottle of the image forming apparatus shown in FIG.

5 is a perspective view showing the image forming unit of the image forming apparatus shown in FIG. 3 with a case cover, a development case cover, and an upper cover removed.

6 is a partial cross-sectional plan view of the image forming unit in the same state as in FIG.

FIG. 7 is a cross-sectional view for explaining the relationship between the developing device and the photoconductor of the image forming unit shown in FIGS.

8 is an exploded perspective view of a doctor blade, a developing sleeve, a supporting member, and an inlet seal cover of the image forming unit shown in FIGS. 3 to 6. FIG.

9 is an enlarged perspective view of a toner recycling belt of the image forming unit shown in FIGS. 3 to 6. FIG.

FIG. 10 is a vertical sectional view of a toner recycling belt of the image forming unit shown in FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Unit case 3 Case body 7 Photoconductor (image carrier) 10 Developing device 11 Developing sleeve 44 First stirring member 45 Second stirring member 75 Toner supply unit 90 Developer chamber

Claims (2)

[Claims] 1. An image carrier on which an electrostatic latent image is formed, a writing optical system for forming an electrostatic latent image on the image carrier at one dot point (pixel) by laser light, and a developing sleeve. A developing sleeve for visualizing the electrostatic latent image formed on the image bearing member as a toner image by using a two-component developer composed of the toner and the carrier, and the developing sleeve is a developing sleeve. The first and second stirring members are arranged parallel to the axis,
The developer is circulated in a loop by each stirring member, and the second stirring member adjacent to the developing sleeve conveys the developer in the developing sleeve axial direction at a speed v _z. Of the developing sleeve and the second stirring member adjacent to the developing sleeve,
A width corresponding to a writing width L by the writing optical system is divided into N blocks, and the number of writing pixels for each L / N width is integrated and stored in association with the moving speed v _z of the developer. , A calculation unit for calculating the toner amount consumed for each block by multiplying the pixel number P accumulated in the width L for each block by the toner adhesion amount D per pixel, and from the calculation result An image forming apparatus comprising means for supplying a toner amount corresponding to a toner consumption amount to the L / N width. 2. The image forming apparatus according to claim 1, wherein a humidity sensor is arranged in the vicinity of the developing device, and the toner adhesion amount D corresponding to the humidity detected by the humidity sensor calculates the previous toner consumption amount. The image forming apparatus is provided with a control unit that feeds back the calculation unit.