JPH09185238A - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to detect the toner end without causing erroneous detection and to replenish the toner at an optimum timing. When the yellow developing device 22Y is at the developing position, a toner end detector 12 using a photo interrupter diode, for example, is attached to the main body of the image forming apparatus near the lower part of the black toner cartridge 11K and is not shown. It is connected to the printer engine board by wiring. When the toner end detector 12 detects the toner end in the toner cartridge, the signal is sent to the printer engine board to count the number of image forming times or the number of hard copies (print number) thereafter, and count the number. It will be stored in the internal memory. When the stored number reaches a certain value, the toner end is notified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a plurality of developing units,
A color copying machine or a color printer using a rotary developing device that is rotatably supported facing the latent image carrier and rotates each developing device to a developing position facing the latent image carrier to perform a developing operation. The present invention relates to an image forming apparatus such as a color facsimile, and more particularly, to toner end detection of a rotary developing device.

[0002]

2. Description of the Related Art Conventionally, a latent image carrier is exposed with a color-separated light image, and each latent image formed is developed with a powder developer (hereinafter, referred to as a toner) complementary to the color-separated light. A full-color image forming apparatus such as a full-color copying machine that superimposes and transfers a plurality of toner images formed on the same transfer paper, or images to be reproduced in different colors are separately exposed on the latent image carrier and formed. There is known a multicolor image forming apparatus or the like in which each latent image is developed with developers of different colors, and a plurality of obtained toner images are superimposed and transferred onto the same transfer paper. In these image forming apparatuses, a plurality of developing units are required to perform development of a plurality of colors. However, if each developing unit is independently configured and arranged side by side around the latent image carrier, the size of the apparatus increases. There was a disadvantage that it would.

Therefore, conventionally, a rotary member is provided so as to be close to the latent image bearing member, and a plurality of developing devices are supported at predetermined positions by the rotary member so that each developing device is supported by the latent image bearing member. A rotary developing device has been developed in which a latent image on a latent image carrier is developed with toner of each color by sequentially rotating and conveying the toners to opposite developing positions.

However, in such a developing device, a volume for storing toner is required in the cross section of each developing device, and there is a drawback that the developing device becomes large in size to secure the volume. Therefore, JP-A-6-
In the image forming apparatus or the like described in JP-A-301288, a rotary type developing device having a toner storage portion and a toner cartridge at one longitudinal end of the developing device, and supplying toner from the toner cartridge to the toner storage portion as the developing device rotates. A device has been proposed.

Further, in the image forming apparatus described in JP-A-60-159872, at least one of a plurality of developing devices using developers of different colors is conveyed and only a predetermined developing device is mounted on the image carrier. When a developing device having the developing device is conveyed and reaches a predetermined position, the toner amount on the toner conveying member of the developing device is detected by a single detecting device. Is proposed.

[0006]

However, this configuration has the following problems. In such a developing device, the toner storage unit and the toner cartridge rotate with the rotation of the developing unit. Therefore, when the toner end detector is provided in the developing unit, the toner storage unit, or the toner cartridge, the signal is output. The connection terminal to be taken into the detection processing unit (printer engine board) of the forming apparatus becomes complicated, or the contact of the connection terminal is repeatedly contacted and separated too many times, which makes the connection unstable and causes an error due to noise. There was a problem that it caused detection.

Further, as the toner end detection, a method of detecting the presence or absence of toner in the toner cartridge from the outside by using a light transmission type sensor such as a photo interrupter diode is used. However, in a rotary developing device having a toner storage unit and a toner cartridge near the developing unit, even if the toner in the toner cartridge is consumed and the toner end is detected, the toner is not stored in the toner storage unit or the toner transport member. However, there is a problem that a part of the supplied toner is wasted because the toner is not completely used up.

Further, in the image forming apparatus proposed in JP-A-60-159872, a method of detecting the density of the developer on the developing sleeve has been proposed, but when the toner end is detected, the toner is already on the developing sleeve. However, the toner density is insufficient in the image formation immediately before that.

The present invention has been made in view of the above-described drawbacks, and an object of the present invention is to detect the toner end without causing an erroneous detection and to replenish the toner at an optimum timing.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is arranged at a predetermined position around a rotation axis and is rotated around the rotation axis to a developing position facing an image carrier to develop the image. A plurality of developing devices, a toner containing portion provided at an end portion of the developing device, a first carrying portion means for carrying the toner from the toner containing portion to the developing device, and a toner containing portion from the developing device. In an image forming apparatus including a second conveying unit that conveys and collects toner and a detector that detects toner end, after the toner end is detected, image formation is performed a predetermined number of times, and then the toner end is notified. It is something to do. The detection means for detecting the toner end is
It is better to detect the toner end in the toner cartridge supplied to the toner containing portion, and it is more preferable that the image formation of a predetermined number of times can be set by operator input. Further, after the toner end is detected, the toner end may be notified based on the image data corresponding to the toner color for which the toner end is detected. The toner end may be notified based on the pixel number and the pixel level of the image data, or the image data is developed. It is even better to make a correction based on the bias value and the detection value of the toner adhesion amount detection means on the image carrier.

[0011]

In the image forming apparatus according to the present invention, after the toner end is detected, the image forming operation is performed a predetermined number of times and then the toner end is notified, so that the toner containing portion, the first toner conveying member and the second It is possible to consume the toner supplied from the toner cartridge without waste, without the toner unnecessarily remaining on the toner conveying member. Further, since the toner end of the toner cartridge is detected, it is possible to secure the degree of freedom of arrangement in the detecting means and consume the toner without waste. Then, the image formation of a predetermined number of times after the toner end is detected can be set by an operator input, so that the time when the toner end is notified and the true toner end time can be accurately matched.

After the toner end is detected, the toner end is notified based on the image data corresponding to the toner color for which the toner end is detected. Therefore, the amount of toner actually consumed is irrespective of the image ratio per page. Can be predicted more accurately, the toner supplied from the toner cartridge can be consumed without waste, and the time when the toner end is notified and the true toner end time can be accurately matched.

By performing the toner end based on the pixel number and the pixel level of the image data corresponding to the toner color detected, the toner amount consumed according to the writing level per dot is taken into consideration. The toner amount can be predicted more accurately, the toner supplied from the toner cartridge can be consumed without waste, and the time when the toner end is notified and the true toner end time can be accurately matched.

By correcting the image data corresponding to the toner color of which the toner end is detected, based on the developing bias value,
It is possible to more accurately predict the toner amount actually consumed by considering the toner amount consumed according to the fact that the developing bias value becomes variable to control the image density. The toner can be consumed without waste, and the time when the toner end is notified and the true toner end time can be accurately matched.

By correcting the image data corresponding to the toner color of which the toner end is detected based on the detection value of the toner adhesion amount detection means on the image carrier, the actual adhesion amount on the image carrier is considered, The amount of toner actually consumed can be predicted more accurately, the toner supplied from the toner cartridge can be consumed without waste, and the time when the toner end is notified and the true toner end time are accurately adjusted. be able to.

[0016]

EXAMPLES A full color printer 1 (hereinafter, referred to as an image forming apparatus using a rotary developing apparatus to which the present invention is applied will be described below.
An example of a printer) will be described. FIG. 1 shows an image forming apparatus using a rotary developing device to which the present invention is applied. In a printer, a belt-shaped photoconductor 1 which is a latent image carrier is uniformly charged by a charging roller 2 which is a charging unit, and then image information (image data) is formed by a laser optical device 3 which is an exposing unit. Based on the scanning exposure, an electrostatic latent image is formed on the surface. Here, the image information to be exposed is monochromatic image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. The formed electrostatic latent image is developed with a predetermined yellow, magenta, cyan, and black toner by a rotary developing device 4 described later, and an image of each color is formed on the photoconductor 1.

Each color image formed on the photoconductor belt 1 rotating in the direction of arrow A in the figure rotates in the direction of arrow B in the figure in synchronization with the photoconductor belt 1, and the intermediate transfer belt 5 as a transfer member. The yellow, magenta, cyan, and black single colors are sequentially transferred and superposed on each other. The yellow, magenta, cyan, and black images superposed on the intermediate transfer belt 5 are transferred as transfer means onto the transfer paper which is conveyed from the paper feed cassette 8 through the paper feed roller 9 and the registration roller 10 to the transfer section. It is collectively transferred by the roller 6. After the transfer is completed, the transfer paper is fixed by a fixing device 7 which is a fixing means, and a full color image is completed.

FIG. 2 shows a rotary developing device relating to the image forming apparatus of the present invention. Photoconductor belt 1 described above
A rotary type (also referred to as a revolver type or rotary type) developing device 4 as a developing device according to the present invention is disposed in the vicinity of. In this rotary type developing device 4, the casing 20 which is a supporting member forming a rotary body has a rotation center O.
The casing 20 is rotatably provided in the direction of arrow C and is rotated in the direction of arrow C by a drive mechanism (not shown). Further, the casing 20 has a shape such that the developing device is divided into four parts, whereby each color developing device 22-Y, M, C ,.
K is formed. These color developing units 22-Y, M,
C and K can be removed from the casing 20.

FIG. 2 shows a state where one developing device 22-Y is in the developing position. Each developing device 22-Y, M, C,
K is a cylindrical developing roller 2 as a developer conveying member.
3-Y, M, C, K are provided. Each of the developing rollers 23-Y, M, C, K is arranged so that a part of the developing roller 23-Y, M, C, K is exposed to the outside through the opening 22a provided in the casing 20. To develop the corresponding electrostatic latent image.

The developing device of this embodiment is a developing device using a non-magnetic one-component developer, and each unit stores yellow, magenta, cyan, and black toners, and selectively rotates around the rotation center O. To the developing position, the electrostatic latent images formed on the photosensitive belt 1 are sequentially developed, and the developed images are superposed on the intermediate transfer belt 5 and the transfer paper as described above to obtain a full-color image. To form.

FIG. 3 shows a developing device according to the present invention, which will be described below with reference to FIG. Each color developing device 22-Y,
Since M, C, and K have the same form and the same operation, only one color developing device 22-Y will be described here. In FIG. 3, the developing device 22-Y is disposed below the photoconductor belt 1 serving as an electrostatic latent image carrier, and is formed on the photoconductor belt 1 located above the developing device 22-Y. Toner as a non-magnetic one-component developer is supplied to the latent image.

In the figure, reference numeral 22 indicates a developing unit,
An opening 22a is formed above the developing device 22 at the developing position facing the photoconductor. In the opening 22a, a developing roller 23 (-Y) as a developer bearing member is arranged in the same direction as the photosensitive member moving direction (arrow D in the figure) so as to face the photosensitive member with a predetermined peripheral speed ratio with the photosensitive member. ) Is arranged to rotate. Further, below the developing roller 23, a supply roller 31 made of an elastic material such as foamed polyurethane as a toner supply member slides on the developing roller 23 and has a predetermined peripheral speed ratio to the developing roller 23. In this case, the developing roller 23 and the contact portion are provided so as to rotate in the same direction (arrow E in the figure).

A thickness of 0.1 m is provided on the downstream side of the supply roller 31 in the moving direction of the developing roller 23 and near the opening 22a.
A thin blade 32 made of a stainless thin plate of about m or an elastic body such as urethane rubber is provided so that one end portion of the thin blade 32 is in contact with the developing roller 23. Reference numeral 33 in the drawing denotes a screw-shaped first toner carrying member, which will be described later, and carries the toner from the front side to the back side in the drawing. Further, this toner carrying member may be an elliptical member as long as it can carry the toner.

On the front side of the developing unit 22, the toner storage unit 1
5 are provided. (See FIG. 4 below) The toner transport member 33 is a screw-shaped first toner transport member,
The developing roller 23 is disposed in parallel with the developing roller 23 and the supply roller 31 from the above-mentioned toner container 15 to the other side plate of the developing device 4, and conveys the toner from the front side to the back side in the drawing. And in conjunction with the supply roller 31,
It is rotated at a predetermined peripheral speed ratio. The inner wall of the casing 20 is arranged so that a part thereof contacts the supply roller 31, and the developing roller 23, the supply roller 31, and the
The casing 20 forms a toner transport space 34 surrounding the toner transport member 33.

Screw-shaped first toner conveying member 33
Is rotated at a predetermined peripheral speed ratio in cooperation with the developing roller 23 and the supply roller 31 so as to convey the toner from the front side to the rear side in the drawing. By this rotation, the first toner conveying member 33 conveys the toner from the toner accommodating portion 15 into the toner conveying space and supplies the toner onto the supply roller 31. The toner supplied onto the supply roller 31 is supplied while being charged on the surface of the developing roller 23 by the supply roller 31, and is carried on the surface of the developing roller 23.
The toner carried on the surface of the developing roller 23 is transferred to the blade 3
The electrostatic latent image formed on the surface of the photoconductor belt 1 by a uniform toner thin layer having a predetermined thickness is developed by contact development.

By the way, the toner not used in the developing step is conveyed by the first toner conveying member 33 to the end portion of the developing device opposite to the toner accommodating portion 15. A space for toner circulation is provided outside the effective diameter portion of the developing roller 23 and the supply roller 31 in the axial direction. The toner carried by the first toner carrying member 33 to the end of the developing device drops to the lower part of the developing device 22 due to gravity.

Below the developing device 22, a screw-shaped second toner conveying member 35 is arranged in parallel with the developing roller 23, the supplying roller 31, and the first toner conveying member 33, and the first toner conveying member 33 is provided. The toner is rotated so as to convey the toner in the direction opposite to that of the toner conveying member 33, and the toner not used in the developing process is conveyed to the toner accommodating portion 15. The second toner carrying member may be made of the same material as the first carrying member, and the carrying can be carried in the opposite direction by reversing the screw shape or rotating the screw in the opposite direction. Further, by appropriately setting the carry amounts of the first toner carrying member 33 and the second toner carrying member 35, it is possible to supply the toner without detecting the toner amount in the developing device 22 or performing complicated supply amount control. It is possible to provide a small-sized developing device that can be supplied onto the roller 31, has a large degree of freedom in layout, and has a small cross-sectional occupation rate with respect to the photosensitive belt. The amount of conveyance can be changed by changing the pitch or rotation speed of the screw, and the second toner conveyance member has a smaller conveyance amount than the first conveyance member.

Further, a toner cartridge is detachably mounted in the toner accommodating portion 15, and is mounted and exchanged when the developing device 4 is newly mounted or at the toner end, so that the toner accommodating portion 15 always accommodates a required amount of toner. To be done.

Next, FIG. 4 is a toner replenishing operation diagram of the rotary developing device of the present invention, and hereinafter, the replenishment of toner from the toner cartridge to the toner containing portion will be described. The toner cartridge 11 mounted in the toner container 15 rotates as the developing device 4 rotates. Here, for example, the developing device 4 is a state in which the yellow developing device 22Y is in the developing position and then the yellow developing device is in the non-developing position after the state shown in FIGS. 4 (B) and 4 (C). Four
When rotated to the state shown in (D), the yellow developing device 22
The toner accommodated in the toner cartridge 11Y mounted in the Y toner accommodating portion 15Y moves in the toner cartridge due to gravity, and as shown in FIG. 4D, the toner cartridge supply port 11aY and the toner accommodating portion. 15
Collect near Y.

When the developing device 4 is further rotated from this state to return to the state shown in FIG. 4A in which the yellow developing device 22Y is at the developing position, the toner accumulated in the vicinity of the replenishing port 11aY is supplied to the replenishing port 11aY. Through toner storage unit 1
It drops to 5Y. According to this configuration, the toner can be transported from the toner cartridge to the toner storage portion and replenished by rotating the rotary developing device once clockwise without providing any toner transport member in the toner cartridge 11Y. .

FIG. 5 is a diagram showing an example of the image forming apparatus of the present invention. As shown in the drawing, when the yellow developing device 22Y is at the developing position, the toner end detector 12 using a photo interrupter diode is attached to the main body of the image forming apparatus near the lower portion of the black toner cartridge 11K, as shown in the drawing. Not connected to the printer engine board by wiring. When the toner end detector 12 detects the toner end in the toner cartridge, the signal is sent to the printer engine board to count the number of image forming times or the number of hard copies (print number) thereafter, and count the number. It will be stored in the internal memory. When the stored number reaches a certain value, the toner end is notified. Note that this notification is to notify the operator, and means such as display, sound, light, and vibration can be considered.

FIG. 6 is a flowchart of an example of the image forming apparatus of the present invention. The toner end detection of toner cartridges of other colors is similarly performed when the developing device rotates and the toner cartridge is at the position of the toner end detector. The detection position is the yellow developing device 22Y.
Is located at a position facing the photoconductor belt, the yellow developing device 22Y
The cartridge 11Y may be detected.

Here, the number of image formations or the number of hard copies (the number of prints) from the detection of the toner end to the toner end display is determined by the toner containing portion, the first toner conveying member and the second toner conveying member. An appropriate number is set to just consume the toner remaining inside. As a result, when the toner end is displayed, problems such as insufficient density and blurring do not occur on the hard copy image, and the remaining amount of toner in the developing device can be minimized. Therefore, the toner supplied from the toner cartridge can be consumed almost completely without waste.

FIG. 7 is a perspective view of the image forming apparatus of the present invention. As shown in FIG. 7, an operation panel 40 is provided in the image forming apparatus of the present invention, and the number of image formations or the number of hard copies (the number of prints) from when the toner end is detected to when the toner end is displayed is displayed. It can be set. This value is set appropriately after being tested under actual conditions in the inspection process of the manufacturing line, or a set value is defined for each toner manufacturing lot, and can be set appropriately by the user or service person. Therefore, the time when the toner end is displayed is more accurately matched with the true toner end, and the toner supplied from the toner cartridge can be consumed almost completely without waste.

FIG. 8 is a flow chart of the second embodiment of the present invention. As shown in FIG. 5, the yellow developing device 22Y
Black toner cartridge 11K when is in the developing position
A toner end detector 12 using, for example, a photo interrupter diode is attached to the main body of the image forming apparatus near the lower part of, and is connected to the printer engine board by wiring not shown. Toner end detector 1
When 2 detects the toner end in the toner cartridge, the signal is sent to the printer engine board, and after that, the total number of pixels of the image data for the color for which the toner end is detected is counted, and the total number of pixels is calculated. It is stored in the memory on the printer engine board. When the stored number reaches a certain value, the toner end is displayed.

By counting the total number of pixels,
Since the amount of toner actually consumed can be more accurately predicted regardless of the image ratio per page, the time when the toner end is displayed can be more accurately matched with the true toner end, and the toner cartridge can be displayed. The toner supplied from can be consumed almost completely without waste.

FIG. 9 is a flow chart of the third embodiment of the present invention. As shown in FIG. 5, the yellow developing device 22Y
Black toner cartridge 11K when is in the developing position
A toner end detector 12 using, for example, a photo interrupter diode is attached to the main body of the image forming apparatus in the vicinity of the lower part of, and is connected to the printer engine board by wiring not shown. Toner end detector 1
When 2 detects the toner end in the toner cartridge, the signal is sent to the printer engine board, and after that, the total number of the product of the pixel number of the image data and the pixel level for the color detected the toner end is counted. , The total number is stored in the memory in the printer engine board. When the stored number reaches a certain value, the toner end is displayed.

In this image forming apparatus, the writing level per dot has a plurality of values (for example, eight values), and the amount of toner consumed varies depending on the writing level.
Therefore, the toner amount actually consumed can be more accurately predicted by counting the total value of the product of the number of pixels of the image data of the color for which the toner end is detected and the pixel level, and therefore the toner end can be estimated. The display time is more accurately matched with the true toner end, and the toner supplied from the toner cartridge can be consumed almost completely without waste. As a counting method, for one pixel, for example, in the case of 8-value, the minimum level is 1, the full dot is 8, and the interval is 2 depending on the writing level.
~ 7, and the total value may be added up.

FIG. 10 is a flow chart of the fourth embodiment of the present invention. As shown in FIG. 5, the yellow developing device 22
When Y is in the developing position, the black toner cartridge 11
In the vicinity of the lower part of K, a toner end detector 12 using, for example, a photo interrupter diode in the main body of the image forming apparatus 12
Are attached to the printer engine board by wiring (not shown). When the toner end detector 12 detects the toner end in the toner cartridge, the signal is sent to the printer engine board, and the number of pixels of the image data for the color after detecting the toner end is weighted by the developing bias value, That is, the total number of corrected values is counted, and the total number is stored in the memory in the printer engine board. When the stored number reaches a certain value, the toner end is displayed.

In this image forming apparatus, the developing bias value is variable in order to control the image density, and the amount of toner consumed varies depending on the developing bias value. Therefore, by weighting the number of pixels of the image data of the color for which the toner end is detected by the developing bias value, that is, by counting the corrected value, it is possible to more accurately predict the toner amount actually consumed. As the toner end is displayed more accurately than the true toner end, the toner supplied from the toner cartridge can be consumed almost completely without waste. As a counting method, for one pixel, for example, the developing bias value is divided into eight levels, the minimum level is set to 1, the maximum level is set to 8, and the interval between them is set to 2 to 7 according to the level of the developing bias. You just have to add up the total value.

FIG. 11 is a flow chart of the fifth embodiment of the present invention. As shown in FIG. 5, the yellow developing device 22
When Y is in the developing position, the black toner cartridge 11
In the vicinity of the lower part of K, a toner end detector 12 using, for example, a photo interrupter diode in the main body of the image forming apparatus 12
Are attached to the printer engine board by wiring (not shown). When the toner end detector 12 detects the toner end in the toner cartridge, the signal is sent to the printer engine board, and the number of pixels of the image data for the color after which the toner end is detected is detected on the toner image carrier. The total number of weighted values is counted based on the output result of the detector that detects the toner adhesion amount, and the total number is stored in the memory in the printer engine board. When the stored number reaches a certain value, the toner end is displayed.

The image forming apparatus is provided with a detector for detecting the toner adhesion amount on the toner image bearing member in order to control the image density, and the toner adhesion amount of a specific pattern is determined by, for example, a photo interrupter. It is detected by a detector using a diode. Therefore, the number of pixels of the image data of the color for which the toner end is detected is weighted based on the output result of the detector that detects the toner adhesion amount on the toner image carrier, that is, the corrected value is counted, Since the amount of toner consumed can be predicted more accurately, the time when the toner end is displayed will match the true toner end more accurately, and the toner supplied from the toner cartridge will be almost perfect without waste. Can be consumed. As a counting method, for one pixel, for example, the output result of the detector that detects the toner adhesion amount on the toner image carrier is divided into eight levels, and the minimum level is set to 1 and the maximum level is set to 8. The interval may be set to 2 to 7 depending on the level of the output result of the detector that detects the toner adhesion amount on the toner image carrier, and the total value may be integrated.

[0043]

The image forming apparatus according to the present invention can detect the toner end and replenish the toner at an optimum timing without causing an erroneous detection.

[Brief description of the drawings]

FIG. 1 is an image forming apparatus using a rotary developing device to which the present invention is applied.

FIG. 2 is a rotary developing device relating to the image forming apparatus of the present invention.

FIG. 3 is a developing device according to the present invention.

FIG. 4 is a toner supply operation diagram of the rotary developing device of the present invention.

FIG. 5 is a diagram showing an example of an image forming apparatus of the present invention.

FIG. 6 is a flowchart of an example of the image forming apparatus of the present invention.

FIG. 7 is a perspective view of the image forming apparatus of the present invention.

FIG. 8 is a flowchart of the second embodiment of the present invention.

FIG. 9 is a flowchart of the third embodiment of the present invention.

FIG. 10 is a flow chart of a fourth embodiment of the present invention.

FIG. 11 is a flowchart of the fifth embodiment of the present invention.

[Explanation of symbols]

1: photoconductor belt, 2: charging roller, 3: laser optical device, 4: rotary developing device, 5: intermediate transfer belt, 6: transfer roller, 7: fixing device,
8: paper feed cassette, 9: paper feed roller,
10: registration roller, 11: toner cartridge, 11a: replenishing port, 12: toner end detector, 15: toner storage section, 20: casing,
22: developing device, 23: developing roller, 3
1: supply roller, 32: thin layer blade, 33:
First toner conveying member, 34: toner conveying space,
35: Second toner conveying member 40: Operation panel

Claims (7)

[Claims] 1. A plurality of developing devices which are arranged at predetermined positions around a rotation shaft and rotate around the rotation shaft to a developing position opposed to an image carrier to perform development, and are provided at an end portion of the developing device. A toner storage unit, a first transport unit unit that transports toner from the toner storage unit to the developing unit, a second transport unit unit that transports and collects toner from the developing unit to the toner storage unit, and a toner end. An image forming apparatus comprising: a detection unit for detecting the toner end, the toner end is detected, the image formation is performed a predetermined number of times, and then the toner end is notified. 2. The image forming apparatus according to claim 1, wherein
The image forming apparatus is characterized in that the detection means for detecting the toner end detects the toner end in the toner cartridge supplied to the toner storage portion. 3. The image forming apparatus according to claim 1, wherein the image forming a predetermined number of times after detecting the toner end can be set by an operator input. 4. A plurality of developing devices, which are arranged in a predetermined arrangement around a rotation shaft and rotate around the rotation shaft to a developing position facing the image carrier to perform development, and are provided at an end portion of the developing device. A toner storage unit, a first transport unit unit that transports toner from the toner storage unit to the developing unit, a second transport unit unit that transports and collects toner from the developing unit to the toner storage unit, and a toner end. An image forming apparatus comprising a detecting unit for detecting, after the toner end is detected, the toner end is notified based on image data corresponding to the toner color for which the toner end is detected. . 5. The image forming apparatus according to claim 4, wherein
An image forming apparatus characterized by performing the toner end detection based on the pixel number and pixel level of image data corresponding to the toner color. 6. The image forming apparatus according to claim 4, wherein
An image forming apparatus, which corrects image data corresponding to a toner color of which a toner end is detected based on a developing bias value. 7. The image forming apparatus according to claim 4,
An image forming apparatus, which corrects image data corresponding to a toner color of which a toner end is detected, based on a detection value of a toner adhesion amount detection means on an image carrier.