JPH1020651A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of storing the detection of the residual amount of toner with simple constitution. SOLUTION: This device is provided with a display means where a display meter 502 moves from right to left in figure by the rotation of a screw 501 so that the residual amount of the toner consumed in a developing device 44 can be confirmed, that is, the display means showing that the residual amount of the toner is larger as the display meter 502 exists on the right further and that it is smaller as the meter 502 moves to the left further. In order to control the means for displaying the residual amount of the toner, the output level (image density signal) of a picture element image signal from an image signal processing circuit is counted for every picture element and the screw 501 is rotated based on the counting.

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 or a printer for detecting the remaining amount of developer, and more particularly to a technique for detecting the remaining amount of developer.

[0002]

2. Description of the Related Art Conventionally, in a developing device of an image forming apparatus, toner as a developer is stored in a toner hopper, and as a method of detecting the amount of toner in the toner hopper, a transparent toner hopper is used. A method has been used in which a window member is provided, and the window member is transmitted through and optically detected. In addition, there are an antenna method for detecting the electric capacity of the toner, a detection method using a piezo element, and the like.

In such a method of detecting the toner itself, since the toner is detected only when the remaining amount of the toner falls below a certain amount, the user has no information about the estimated amount of the remaining toner. In addition, there is a problem of poor maintainability in which a shortage of toner is suddenly reported.

On the other hand, as means for detecting the remaining toner amount by estimating the consumption amount, an image is formed based on digital image data (video data) as in a digital copying machine such as an LBP (laser beam printer). 2. Description of the Related Art In an image forming apparatus, there is an indirect remaining amount detection method in which the remaining amount of toner is detected by a video counter method. In this method, the amount of toner consumption is calculated from video data and sequentially calculated, so that the remaining amount of toner can be almost accurately transmitted to the user in real time.

[0005]

However, in the video counter system, it is necessary to store the calculation result of the remaining toner amount so that the result does not disappear even when the power switch is turned off. If the developing device is formed as a single unit or as a cartridge together with a photoreceptor, the amount of toner remaining for each cartridge is required to be stored in the main body. In some cases, it became complicated and cost increased. Also, when the cartridge is used in another main body, the video counter method cannot be used for the cartridge in some cases. For example, the remaining toner data stored in the main body becomes meaningless.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of storing a toner remaining amount detection with a simple configuration.

[0007]

According to a first aspect of the present invention, there is provided an image carrier having a photosensitive layer and an electrostatic latent image corresponding to an image information signal on the image carrier. Means for forming, a developing device for developing the electrostatic latent image using a developer to form a visible image, a transfer means for transferring the visible image to a transfer material, and image density information of the image information signal. Calculating means for calculating the amount of developer consumption in accordance with the image forming apparatus, wherein in the image forming apparatus in which the developing device is detachably mounted, a developer remaining amount displaying means for displaying the remaining amount of developer on the developing device is provided. This is achieved by providing control means for controlling the developer remaining amount display means according to the information of the calculation means.

[0008] According to a second aspect of the present invention,
The above object is achieved in the first aspect by controlling the developer remaining amount display means simultaneously with the developing operation.

Further, according to a third aspect of the present invention, the above object is achieved by providing the first aspect with a correction means for correcting the developer consumption calculating means.

According to the first aspect of the present invention, an electrostatic latent image corresponding to an image information signal is formed on an image carrier and visualized by a developer of a developing device. Is calculated by the calculating means in accordance with the image density information of the image information signal, and based on the calculation result, the control means controls the developer remaining amount display means of the developing device, and the developer The remaining amount is displayed. Therefore, even when the developing device is detached, the remaining amount of the developer in the developing device is clarified by the remaining developer amount display means of the developing device.

Further, according to the second invention of the present application,
In the first aspect, since the developer remaining amount display means is controlled simultaneously with the developing operation, even if the image forming operation is temporarily interrupted due to any trouble, the developer remaining amount at that time can be accurately determined. Is displayed.

Further, according to the third invention of the present application, in the first invention, since the correction means for correcting the developer consumption calculating means is provided, the accurate remaining developer amount display is always performed. Will be

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS.

An image forming apparatus to which the present invention can be applied forms a latent image on an image carrier such as a photoreceptor or a dielectric by an electrophotographic system, an electrostatic recording system, or the like, and converts the latent image into a single component. Or a two-component) developing device using a developer to form a visible image (toner image), transfer the visible image to a transfer material such as paper, and form a permanent image by fixing means. I just need.

First, an overall configuration of an example of an image forming apparatus according to the present invention will be described with reference to FIG. Here, a case is shown in which the present invention is applied to an electrophotographic digital copying machine, but it goes without saying that the present invention can be equally applied to various other image forming apparatuses of the electrophotographic type and the electrostatic recording type.

First, the schematic configuration of the apparatus shown in FIG. 1 will be described. In FIG. 1, an image of a document 31 to be copied is projected by a lens 32 onto an image sensor 33 such as a CCD. The image sensor 33 decomposes the image of the document 31 into a number of pixels and generates a photoelectric conversion signal corresponding to the density of each pixel. The analog image signal output from the image sensor 33 is sent to an image signal processing circuit 34, where the image signal is converted into a pixel image signal having an output level corresponding to the density of the pixel. Sent.

The pulse width modulation circuit 35 forms and outputs a laser drive pulse having a width (time length) corresponding to the level of each input pixel image signal. That is, as shown in FIG. 2A, a wider drive pulse W is applied to a high-density pixel image signal, and a narrower drive pulse S is applied to a low-density pixel image signal. , A driving pulse I having an intermediate width is formed for the medium-density pixel image signal.

The laser driving pulse output from the pulse width modulation circuit 35 is supplied to the semiconductor laser 36, and causes the semiconductor laser 36 to emit light for a time corresponding to the pulse width. Therefore, the semiconductor laser 36 is driven for a longer period of time for the high-density pixels, and is driven for a shorter period of time for the low-density pixels. Therefore, the photosensitive drum 40
By using an optical system described later, a longer range is exposed in the main scanning direction for high-density pixels, and a shorter range is exposed in the main scanning direction for low-density pixels. That is, the dot size of the electrostatic latent image differs according to the density of the pixel.
Therefore, it goes without saying that the toner consumption for the high density pixels is larger than that for the low density pixels. In FIG. 2D, the electrostatic latent images of the low, medium and high density pixels are indicated by L, M and H, respectively.

The laser beam 36a emitted from the semiconductor laser 36 is swept by a rotating polygon mirror 37, and a lens 38 such as an f / θ lens and a fixed mirror for directing the laser beam 36a toward a photosensitive drum 40 as an image carrier. By 39, a spot image is formed on the photosensitive drum 40. Thus, the laser light 36a scans the photosensitive drum 40 in a direction substantially parallel to the rotation axis of the photosensitive drum 40 (main scanning direction), and forms an electrostatic latent image.

The photosensitive drum 40 is an electrophotographic photosensitive drum having amorphous silicon, selenium, OPC or the like on its surface and rotating in the direction of the arrow. It is more uniformly charged.
Thereafter, exposure scanning is performed with a laser beam modulated in accordance with the image information signal described above, whereby an electrostatic latent image corresponding to the image information signal is formed. This electrostatic latent image is reversely developed by a developing device 44 using a toner which is a one-component developer composed of only toner particles. Visible image (toner image)
Is formed. Here, the reversal development is a development method in which a toner charged to the same polarity as the latent image is attached to an image area of the photoconductor exposed to light, and the toner is visualized. This toner image is stretched between two rollers 45 and 46 and is transferred endlessly in a direction indicated by an arrow in the drawing.
8 is transferred by the action of a transfer charger 49 as a transfer means.

As will be described later, a pixel density changeover switch 77 is provided in the present embodiment, and the pulse width modulation circuit 35 is controlled by a pixel density changeover signal from the pixel density changeover switch 77 to provide a pixel forming method. The pulse width of the pulse signal output from the pulse width modulation circuit 35 is changed in accordance with the difference.

For simplicity of explanation, only one image forming station (including a photosensitive drum 40, an exposing device 41, a primary charger 42, a developing device 44, etc.) is shown. In this case, for example, four image forming stations for each color of cyan, magenta, yellow, and black are sequentially arranged on the transfer material carrying belt 47 along the moving direction, and on the photosensitive drum of each image forming station. An electrostatic latent image of each color obtained by color-separating the image of the original is sequentially formed, developed by a developing device 44 having a corresponding color toner, and sequentially transferred onto a transfer material 48 held and transported by a transfer material carrying belt 47. Will be transcribed.

The transfer material 48 onto which the toner image has been transferred is separated from the transfer material carrying belt 47, conveyed to a fixing device (not shown), fixed, and converted into a permanent image. Further, the residual toner remaining on the photosensitive drum 40 after the transfer is removed by the cleaner 50 thereafter.

Next, an example of the developing device 44 is shown in FIG. As shown in FIG. 1, the developing device 44 arranged opposite to the photosensitive drum 40 has a first container (developing container) 52 and a And two containers (one-component developer container (toner container)) 53. The first container 52 includes a non-magnetic developing sleeve 54 serving as a developer carrier that rotates in the direction of the arrow, a fixedly arranged blade 55 that abuts the developing sleeve 54 to apply a thin layer of toner and apply a charge. Supply roller 56 for supplying toner to developing sleeve 54
It is composed of

The developing sleeve 54 is supplied with the toner by the supply roller 56, carries and transports the toner layer of which the thickness is regulated by the blade 55, and transfers the toner in the developing area opposed to the photosensitive drum 40. To develop the electrostatic latent image. Further, in order to improve the developing efficiency, that is, the rate of toner application to the latent image, the developing sleeve 5
4, a developing bias voltage in which a DC voltage is superimposed on an AC voltage is applied from a power supply (not shown).

In the second container (toner container) 53,
A stirring member 57 that stirs and conveys the toner into the developing container from the toner container opening 53a is rotatably disposed. The stirring member 57 rubs a stirring stay 57a such as a sheet metal or the like against the wall of the toner container 53. It is composed of wings 57b.

The developing device 44 is detachably provided to the main body of the image forming apparatus. Even when the developing device 44 is detached from the image forming apparatus, the developing device 44 consumes the developing device in developing the electrostatic latent image. To check the toner level,
The developing device 44 is provided with, as shown in FIG. In the figure, reference numeral 501 denotes a screw;
Are moved from right to left in the figure by the rotation of the screw 501. That is, it means that the more the display meter is to the right, the more the remaining amount of toner is, and the further to the left, the less the remaining amount of toner is.

In order to control the toner remaining amount display means, the output level (image density signal) of the pixel image signal from the image signal processing circuit 34 is counted for each pixel. This is performed as follows.

First, as shown in FIG. 1, the output signal of the pulse width modulation circuit 35 is supplied to one input of an AND gate 64, and the other input of the AND gate 64 is supplied from a clock pulse generator 65. Clock pulse (Fig. 2
(Pulse shown in (b)). Therefore, as shown in FIG. 2C, the AND gate 64 outputs a number of clock pulses corresponding to the respective pulse widths of the laser driving pulses S, I and W, that is, a number of clock pulses corresponding to the density of each pixel. A pulse (corresponding to the image density signal) is output.

The number of clock pulses is converted into a signal (number of pulses) in accordance with an actual toner consumption characteristic by an 8-bit image density signal conversion table 78. Since the relationship between the image density signal and the actual image density has the characteristic indicated by the solid line in FIG. 5, the conversion table 78 is a conversion table having the characteristic indicated by the solid line in FIG. 6, and converts the input image density signal into the actual image density characteristic. The image is converted into a corresponding image density signal. For example,
If the input image density signal (the number of pulses) is 70 of the 255 levels, the conversion table shown in FIG.
The signal is converted into an 80-level signal and output. Therefore, the output signal converted by the conversion table 78 becomes an image density signal that matches the actual toner consumption characteristics in which the nonlinear relationship between the input image density signal and the actual image density has been corrected. Since the input image density signal is 8 bits (0 to 255), an 8-bit conversion table 78 is used, but the number of bits in the conversion table 78 is appropriately changed according to the input image density signal. .

The image density signal from the conversion table 78 is integrated by the counter 66 to calculate a video count (A4 maximum video count is 3707 × 1).
0 ^6). Thus, the pulse integration signal C1 (video count number) for each image from the counter 66 accurately corresponds to the amount of toner actually consumed by the developing device 44 in order to form one toner image on the document 31. Will do.

Therefore, this video count is supplied to the CPU 67 which is a calculating means and a controlling means, and the RAM 6
8 is stored. The CPU 67 has a conversion table indicating the correspondence between the video count number and the amount by which the screw 501 of the toner remaining amount display means is rotationally driven. The conversion table is consumed from the developing device 44 based on the input video count number. The amount of rotation of the screw 501 corresponding to the amount of toner is calculated, and the motor driving circuit 69 is controlled to drive the motor 70 for the calculated time. Thus, generally, if the video count is large, the motor 70
Is longer, and if the video count is small, the driving time of the motor 70 is shorter.

The driving force of the motor 70 is the gear train 71.
And the display screw 502 is moved to the conveying screw 501 to display the remaining amount of toner.

By controlling the display of the remaining amount of toner at the same time as the development in one image formation, it is possible to display the remaining amount more accurately. This is because, in the event of a device failure, the consumed toner is calculated at the same time and the display is changed. Is displayed.

Further, the image of the document to be copied is photoelectrically converted as described above, the output level of each pixel of the pixel image signal obtained by signal processing is integrated, and converted into a video count number to be consumed. Is different from the method of directly detecting the actual consumption amount of the developer and displaying the remaining toner amount based on the method. When the amount of toner consumption from the device 44 changes from the predicted value, the amount of toner consumption gradually deviates from the actual remaining amount. If this deviation is not corrected, the notice of cartridge replacement or toner replenishment timing will be significantly deviated.

For this reason, a developer consumption correction means is provided,
This developer consumption correction means is provided at a predetermined timing, for example, at each time when the number of copies reaches a certain number,
By operating, a reference image is formed on the photosensitive drum 40.

In the apparatus shown in FIG. 1, a reference image signal generating circuit 72 for generating a reference image signal having a signal level corresponding to a predetermined density is provided. The laser drive pulse is supplied to the width modulation circuit 35 and has a pulse width corresponding to the predetermined density. The laser drive pulse is supplied to the semiconductor laser 36, the laser 36 emits light for a time corresponding to the pulse width, and the photosensitive drum 40 is scanned (at this time, the counter 66 is not operated). As a result, a reference electrostatic latent image corresponding to the predetermined density is formed on the photosensitive drum 40, and the reference electrostatic latent image is developed by the developing device 44. The patch-like reference toner image thus obtained is irradiated with light from a light source 73 such as an LED, and the reflected light is converted into a photoelectric conversion element 74.
To receive light. Since the output signal of the photoelectric conversion element 74 corresponds to the density of the reference toner image, a change in the relationship between the actual image information signal of the toner and the image density in the developing device 44 at that time is finally detected by the output signal. Then, by correcting the image density signal and outputting the image, it is possible to accurately calculate the toner consumption.

The output signal of the photoelectric conversion element 74 is supplied to one input of a comparator 75. To the other input of the comparator 75, a reference signal corresponding to a specified toner consumption of toner (toner consumption at an initial set value) is input from a reference voltage signal source. Therefore, the comparator 75 compares the specified toner consumption with the actual toner consumption in the developing device 44 after the fixed number of sheets have been operated. As a result of comparing the two input signals, the comparator 75 sets the developing device 44 An output signal indicating that the actual consumption of the toner in the printer is larger than the specified value or an output signal indicating that the toner consumption is smaller than the specified value is generated. If there is no difference between the two input signals, an output signal indicating the difference may be generated.

More preferably, the image forming apparatus is provided with a detecting means for detecting when the remaining amount of toner by means of the remaining toner amount display means provided in the developing device or the cartridge (not shown) falls below a certain amount. Thereby, an effect is obtained that the user can be notified that the remaining amount of toner is low. For example, a sensor or the like that can detect that the display meter 502 in FIG.

Although the configuration as shown in FIG. 4 is used as the toner remaining amount display means, the present invention is not limited to this, and the image forming apparatus using a memory or the like other than the mechanical display means may be used. It goes without saying that the effect of the invention is not impaired regardless of the configuration of the display means that can be controlled.

Although an example using a one-component development method has been described here, the present invention is not limited to this, and the effect of the invention is not impaired by using a two-component development method.

(Second Embodiment) In the first embodiment, an example using a digital copying machine has been described. However, the present invention is not limited to this, and an analog exposure system such as an analog copying machine is used. The effect of the invention is not lost even in the above method.

Hereinafter, as a second embodiment, an example in which the present invention is applied to a color copying machine configured to form an analog full-color image of three colors will be described with reference to FIG.

FIG. 7 is a sectional view showing the structure of this type of multicolor image forming apparatus. Reference numeral 605 denotes a two-layer selenium-based photosensitive drum (photoconductor) sensitized by panchromatic and long wavelength.
Denotes a static eliminator and 606 denotes a charger.

An original is illuminated by a halogen lamp in an illuminator 601, and a mirror, a lens 602, a color separation filter 60
An optical image is formed on the photoreceptor through 3.

On the other hand, in the document illuminating section, a line sensor 630 having a color separation filter extracts an image density signal when each of M, C, and Y images is illuminated.
In the same manner as the method in the first embodiment, the toner consumption (video count number) is calculated (when calculating the toner consumption, a conversion table in consideration of the characteristics of the image density signal and the actual image density is calculated in advance. Then, the video count is calculated in consideration of the image density characteristic in analog development.

Reference numerals 609 to 611 denote M (magenta), C (cyan) and Y (yellow) cartridge developing devices, which develop latent images corresponding to the cartridges by a one-component developing method. At the same time as developing for each color developing device, according to the toner consumption obtained at the time of image illumination,
By moving the remaining toner amount display means (not shown) as used in the first embodiment, a guide of the remaining toner amount is recorded for each developing device.

The paper fed from the paper feed unit 618 is wound around a transfer drum 613 formed of a dielectric film rotating in synchronization with the photosensitive member 605 with the same diameter as the photosensitive drum 605, and a toner image is transferred by a transfer charger 614. It is sequentially transcribed a specified number of times,
Upon completion, the paper is discharged and separated by the separation unit 615, and discharged through the fixing unit 620. The toner remaining on the photoconductor 605 is removed by the magnetic brush cleaning 617 via the neutralizer 616. Reference numeral 619 denotes a transfer paper transport system.

By adopting such a configuration, by fetching image data at the time of document illumination and calculating the amount of toner to be analog-developed, the effect of the present invention can be obtained as in the digital system. .

In the above embodiment, the present invention has been described with reference to a case where the present invention is applied to a developing device having a cartridge detachably mounted on an image forming apparatus and an image forming apparatus having the developing device. However, the present invention is not limited to this, and can be applied to a so-called process cartridge that is integrally formed including an image carrier such as a photosensitive drum and a cleaning unit and a charger and the like, and is detachably attached to the image forming apparatus. is there.

[0052]

As described above, the first embodiment according to the present application is described.
According to the invention, an electrostatic latent image corresponding to the image information signal is formed on the image carrier and is visualized by the developer of the developing device. Is calculated in accordance with the image density information of the image information signal. Based on the calculation result, the control means controls the developer remaining amount display means of the developing device, and the remaining developer amount is displayed. It is possible to reliably recognize the accurate remaining amount of the developer in accordance with the developer consumption characteristics.

According to the second aspect of the present invention,
In the first aspect, since the developer remaining amount display means is controlled simultaneously with the developing operation, even if the image forming operation is temporarily interrupted due to any trouble, the developer remaining amount at that time can be accurately determined. Can be recognized.

Further, according to the third invention of the present application, in the first invention, since the correction means for correcting the developer consumption calculating means is provided, the remaining amount of the developer is always accurately recognized. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of counting toner consumption information of an image information signal in the image forming apparatus of FIG.

FIG. 3 is a sectional view illustrating a schematic configuration of a developing device included in the image forming apparatus of FIG. 1;

FIG. 4 is a diagram illustrating an example of a remaining toner amount display unit included in the developing device of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between an image density signal and an actual image density OD.

FIG. 6 is a diagram illustrating an example of a conversion table for converting an input density signal into an image density signal according to an actual density characteristic.

FIG. 7 is a configuration diagram of an image forming apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 40 photosensitive drum (image carrier) 44 developing device 49 transfer charger (transfer unit) 54 developing sleeve (developer carrier) 67 CPU (calculation unit, control unit) 501 display meter (developer remaining amount display unit) 502 Screw (remaining developer display means)

Claims (3)

[Claims] 1. An image carrier having a photosensitive layer, means for forming an electrostatic latent image corresponding to an image information signal on the image carrier,
A developing device that develops the electrostatic latent image using a developer to form a visible image; a transfer unit that transfers the visible image to a transfer material; and a developer that consumes the developer according to image density information of the image information signal. An image forming apparatus in which the developing device is detachably provided, wherein the developing device further includes a developer remaining amount displaying means for displaying a developer remaining amount on the developing device; An image forming apparatus comprising: a control unit that controls the developer remaining amount display unit according to information of the unit. 2. The image forming apparatus according to claim 1, wherein the developer remaining amount display means is controlled simultaneously with the developing operation. 3. The image forming apparatus according to claim 1, further comprising a correction unit that corrects the developer consumption calculation unit.