JP2004191719A - Image forming apparatus and toner consumption calculating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately obtain toner consumption as for an image forming apparatus for forming an image with the toner. <P>SOLUTION: In a regular image forming operation, the number of printed dots is counted based on an image signal, then, the toner consumption is calculated based on the result. On the other hand, in an irregular mode operation other than the regular image forming operation, a test pattern offset value Totn is extracted as the toner consumption corresponding to the operation (step S141). By subtracting the offset value Totn and a drive offset value Todn equivalent to the quantity of toner scattering into the apparatus from the remaining toner quantity Tr stored by a memory, the remaining toner quantity after the operation is obtained (steps S142 to S146). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for determining toner consumption in an image forming apparatus that forms an image using toner.
[0002]
[Prior art]
2. Description of the Related Art In an image forming apparatus such as a printer, a copying machine, and a facsimile apparatus that forms an image using toner, it is necessary to grasp the amount of toner consumption or the amount of toner remaining for maintenance such as toner supply. In view of this, the present applicant has already disclosed a toner consumption detection method and apparatus capable of accurately calculating the toner consumption with a simple configuration (see Patent Document 1). In this detection method and apparatus, in view of the fact that the relationship between the value of a print dot and the amount of toner consumed is non-linear and changes depending on the state of a print dot adjacent to the print dot, the print dot row is divided into two isolated dots. The pattern is divided into three patterns of dots and intermediate value dots, the number of the formed patterns is counted for each of these patterns, and the toner consumption is calculated based on the counted value.
[0003]
[Patent Document 1]
JP-A-2002-174929 (page 4)
[0004]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional patent document 1, the toner consumption in the normal image forming operation can be obtained by using the printing dots, but the operation in the non-normal mode other than the normal image forming operation is completely considered. Absent. However, since an operation in which toner is eventually consumed even in an operation in the non-normal mode can be considered, the toner consumption cannot be accurately obtained unless such an operation is considered.
[0005]
SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus capable of accurately calculating a toner consumption by considering toner consumption in an operation other than a normal image forming operation. It is intended to provide a calculation method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to the present invention consumes a normal toner image forming operation in an image forming apparatus that forms a toner image on an image carrier based on input image data. The toner based on the sum of the first integrated value obtained by integrating the first toner amount and the second integrated value obtained by integrating the second toner amount consumed during the operation in the non-normal mode other than the normal toner image forming operation. It is characterized by finding the amount of consumption.
[0007]
According to the invention configured as described above, the first integrated value obtained by integrating the first toner amount consumed at the time of the normal toner image forming operation and the first integrated value at the time of the operation in the non-normal mode which is not the normal toner image forming operation Since the amount of toner consumed in the entire apparatus is obtained from the sum of the second integrated value obtained by integrating the second toner amount consumed in the printer, the toner consumption amount can be obtained with high accuracy.
[0008]
Further, a storage unit for storing an offset value set in advance in correspondence with the non-normal mode may be further provided, and the offset value may be used as the second toner amount. That is, the amount of toner consumed in the non-normal mode can be obtained experimentally in advance. Therefore, if the toner amount is stored in the storage unit as an offset value, the second toner amount can be easily obtained.
[0009]
Note that this offset value is not limited to a single value. That is, "the operation in the non-normal mode other than the normal toner image forming operation" is an operation that results in the consumption of toner, and a plurality of operations are considered. It is considered that the toner amounts differ from each other. Therefore, offset values respectively set corresponding to a plurality of operations as operations in the non-normal mode are stored in storage means, and when the operations in the non-normal mode are executed, the operations correspond to the operations. An offset value may be extracted from the storage unit, and the extracted offset value may be used as the second toner amount. As a result, the second toner amount consumed in each operation in the non-normal mode is integrated, so that the toner consumption amount can be obtained with higher accuracy.
[0010]
The plurality of operations in the non-normal mode include, for example, an image forming condition adjusting operation performed by forming a patch image, a toner spraying operation performed when the power of a new apparatus is first turned on, and toner deterioration. If at least two of the refresh operation for preventing the toner and the idling operation of the toner container for agitating the contained toner for preventing the deterioration of the toner and the uneven distribution of the toner are included, at least two operations are included in the included operations. The second toner amount to be used can be considered, and the toner consumption amount can be accurately obtained.
[0011]
Further, the offset value may be affected by the properties of the toner and image forming conditions. Among them, the properties of the toner can be obtained by examining the operation status of the apparatus and the usage history of the toner. Therefore, in the present invention, the offset value may be appropriately changed and set by associating the time-dependent change in the properties of the toner with the operation state of the apparatus and the history of toner use. In this case, even if the properties of the toner change, the offset value is set according to the change, so that the toner consumption can be accurately obtained.
[0012]
Also, when the image forming condition changes, the offset value may change. Therefore, in the present invention, since the offset value is changed and set in accordance with the image forming condition, the offset value corresponding to the image forming condition is always set, and the toner consumption can be obtained with high accuracy.
[0013]
In addition, in order to obtain the first toner amount consumed during the normal toner image forming operation, for example, the number of print dots forming the toner image is counted based on the image data, and based on the count value. You can ask. By doing so, the first toner amount can be obtained only by calculation, so that a sensor or the like for measuring the toner amount is not required, and the apparatus configuration and control can be simplified.
[0014]
In addition, since the amount of toner consumption can be accurately determined by the above-described method, the degree of toner reduction in the apparatus can be accurately grasped. Therefore, a determination function may be provided for determining that the toner is exhausted when the toner consumption thus obtained exceeds a predetermined value. This predetermined value can be determined based on the amount of toner initially contained in the apparatus and the minimum amount of toner required in the apparatus to form an image with a predetermined image quality in the apparatus.
[0015]
According to another aspect of the present invention, there is provided a method for calculating a toner consumption amount, in an image forming apparatus which forms a toner image on an image carrier based on input image data, in a normal toner image forming operation. Determining a first toner amount consumed during the operation based on the image data, and determining a second toner amount consumed during an operation in a non-normal mode that is not a normal toner image forming operation. The total consumed toner amount is obtained based on the sum of a first integrated value obtained by integrating the first toner amount and a second integrated value obtained by integrating the second toner amount.
[0016]
According to the invention configured as described above, the first toner amount consumed during the normal toner image forming operation and the second toner amount consumed during the non-normal mode operation that is not the normal toner image forming operation The amount can be obtained individually by a method according to each toner consumption mode, and the first integrated value obtained by integrating the first toner amount and the second integrated value obtained by integrating the second toner amount are added up. In addition, the total amount of consumed toner can be accurately and easily obtained.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. This image forming apparatus forms a full-color image by superimposing four color toners of yellow (Y), magenta (M), cyan (C), and black (K), or uses only black (K) toner. To form a monochrome image. In this image forming apparatus, when a print command and image data are given to the main controller 11 of the control unit 1 from an external device such as a host computer, the main controller 11 outputs a control command to each unit of the device and outputs the given image. Based on the data, an image signal is generated for each toner color that represents an image to be formed as a print dot array of multiple gradation levels, and is output to the engine controller 12. Then, in response to a command from the main controller 11, the engine controller 12 controls each part of the engine EG to form an image corresponding to the image signal on the sheet S.
[0018]
In this engine EG, the photoconductor 2 is provided rotatably in the arrow direction D1 in FIG. A charging unit 3, a rotary developing unit 4, and a cleaning unit 5 for charging the surface of the photoconductor 2 to a predetermined surface potential are arranged around the photoconductor 2 along the rotation direction D1. The charging unit 3 is applied with a charging bias from the charging bias generation unit 121 and uniformly charges the outer peripheral surface of the photoconductor 2.
[0019]
Then, the light beam L is emitted from the exposure unit 6 toward the outer peripheral surface of the photoconductor 2 charged by the charging unit 3. As shown in FIG. 2, the exposure unit 6 is electrically connected to an exposure power control unit 123, and based on a modulation signal corresponding to an image signal given via an image signal switching unit 122, the exposure power control unit Reference numeral 123 controls each part of the exposure unit 6, and exposes the photoconductor 2 with the light beam L to form an electrostatic latent image on the photoconductor 2 corresponding to an image signal.
[0020]
For example, based on a command from the CPU 124 of the engine controller 12, when the image signal switching unit 122 is conducting with the pattern creation module 125 (operation in an unusual mode described later), the image is output from the pattern creation module 125. A modulation signal corresponding to the image pattern is provided to the exposure power control unit 123, and an electrostatic latent image is formed.
[0021]
On the other hand, when the image signal switching unit 122 is in conduction with the CPU 111 of the main controller 11 (a normal image forming operation described later), the image signal supplied from an external device such as a host computer via the interface 112 is modulated. The signal generator 210 performs, for example, pulse width modulation (PWM), and the modulated signal is supplied to the exposure power controller 123. Then, the photoconductor 2 is exposed by the light beam L based on the modulation signal, and an electrostatic latent image corresponding to the image signal is formed on the photoconductor 2. The modulation method is not limited to PWM, and various pulse modulation methods such as pulse amplitude modulation (PAM) can be adopted.
[0022]
The electrostatic latent image thus formed is visualized by the rotary developing unit 4. That is, in this embodiment, as the developing unit 4, a developing unit 4K for black, a developing unit 4C for cyan, a developing unit 4M for magenta, and a developing unit 4Y for yellow are provided rotatably about the axis. . The developing units 4K, 4C, 4M, and 4Y are rotationally positioned, and the developing rollers 40K, 40C, 40M, and 40Y of the developing units 4K, 4C, 4M, and 4Y are selectively provided with respect to the photosensitive member 2. The toner of the selected color is supplied to the surface of the photoreceptor 2 from the developing roller by the developing roller 126 being applied with a developing bias by the developing bias generating unit 126. Thus, the electrostatic latent image on the photoconductor 2 is visualized in the selected toner color. Thus, in this embodiment, the photoconductor 2 functions as the “image carrier” of the present invention.
[0023]
The toner image developed by the developing unit 4 as described above is primarily transferred onto the intermediate transfer belt 71 of the transfer unit 7 in the primary transfer area TR1. Further, a cleaning unit 5 is disposed at a position in the circumferential direction (rotational direction D1 in FIG. 1) from the primary transfer area TR1, and the toner remaining on the outer peripheral surface of the photoconductor 2 after the primary transfer. Is scraped off by the cleaning blade 51. Further, the surface potential of the photoconductor 2 is reset by a charge removing unit (not shown) as necessary.
[0024]
The transfer unit 7 includes an intermediate transfer belt 71 stretched over a plurality of rollers, and a driving unit (not shown) for driving the intermediate transfer belt 71 to rotate. When the color image is transferred to the sheet S, the color image is formed by superimposing the toner images of each color formed on the photoreceptor 2 on the intermediate transfer belt 71, and a predetermined secondary transfer area TR2 is formed. , The color image is secondarily transferred onto the sheet S taken out of the cassette 8. Further, the sheet S on which the color image is formed is conveyed via the fixing unit 9 to a discharge tray provided on the upper surface of the apparatus main body. After the secondary transfer, the toner remaining on the intermediate transfer belt 71 is removed from the intermediate transfer belt 71 by a cleaning unit (not shown).
[0025]
Further, a patch sensor PS is disposed to face the surface of the intermediate transfer belt 71, and when performing an image forming condition adjusting operation described later, the optical density of the patch image formed on the outer peripheral surface of the intermediate transfer belt 71 is determined. Measure.
[0026]
Further, as shown in FIG. 2, the developing units 4K, 4C, 4M, and 4Y are provided with unit-side communication units 41K, 41C, 41M, and 41Y, respectively, and the unit-side communication units 41K, 41C, 41M, and 41Y are provided. Are electrically connected to the memories 42K, 42C, 42M, and 42Y, respectively. The memories 42K, 42C, 42M, and 42Y store various data relating to the production lots, use histories, characteristics of the built-in toner, the remaining amount of the toner, and the like of each of the developing devices 4K, 4C, 4M, and 4Y. Further, the apparatus main body is provided with a main body side communication unit 128 electrically connected to the CPU 124.
[0027]
When the developing rollers 40K, 40C, 40M, and 40Y of the developing devices 4K, 4C, 4M, and 4Y are selectively positioned opposite to the photoconductor 2, the unit-side communication unit of the selected developing device is It is configured to face the main body side communication unit 128 within a predetermined distance, for example, within 10 mm, and can transmit and receive data in a non-contact state with each other by wireless communication such as infrared rays. As a result, the CPU 124 manages various types of information such as detection of mounting of the developing device, detection of a new product, and management of life.
[0028]
In this embodiment, data is transmitted and received in a non-contact manner using electromagnetic means such as wireless communication. However, for example, connectors are provided on the apparatus main body and each of the developing devices 4K, 4C, 4M, and 4Y. When each of the developing devices 4K, 4C, 4M, and 4Y is selectively positioned to face the photoconductor 2, the connector of the apparatus main body is mechanically fitted with the connector of the developing device to transmit and receive data mutually. It may be performed. The memories 42K, 42C, 42M, and 42Y are preferably non-volatile memories that can store data even when the power is off or the developing units 4K, 4C, 4M, and 4Y are removed from the apparatus main body. As the non-volatile memory, for example, an EEPROM such as a flash memory, a ferroelectric memory (Ferroelectric RAM), or the like can be used.
[0029]
In FIG. 2, an image memory 113 provided in the main controller 11 is for storing image data given via an interface 112 from an external device such as a host computer. Further, the memory 127 provided in the engine controller 12 includes a ROM for storing a control program executed by the CPU 124 and a RAM for temporarily storing a calculation result in the CPU 124, control data for controlling the engine EG, and the like. Become. Further, a dot counter 200 is provided in the main controller 11 of the image forming apparatus.
[0030]
FIG. 3 is a block diagram showing the configuration of the dot counter. FIG. 4 is a diagram for explaining a counting procedure by the dot counter, and shows an example of a tone value of a printing dot. The dot counter 200 determines the type of print dots formed on the photoconductor 2 based on an image signal output from the main controller 11 to the engine controller 12 and counts the number of the print dots. More specifically, the dot counter 200 includes a comparison circuit 201, a determination circuit 202, and three counters 203 to 205.
[0031]
As shown in FIG. 3, an image signal given to the engine controller 12 from the CPU 111 of the main controller 11 is input to the comparison circuit 201. Then, the comparison circuit 201 compares the gradation level of the image signal corresponding to each print dot with predetermined thresholds L1 and L2. The threshold value L1 is set to a value close to the gradation 0 (that is, 1/63 of the maximum gradation MAX), and the threshold value L2 is set to a value close to the maximum gradation MAX (that is, 48 / MAX of the solid image). 63). Then, the comparison circuit 201 outputs the value “11” to the determination circuit 202 when the gradation level is equal to or larger than the threshold L2, and outputs the value “00” when the gradation level is smaller than the threshold L1. In response to this, the determination circuit 202 determines the continuous state of each print dot, that is, whether or not there is a dot adjacent to the target print dot, and outputs a signal corresponding to the result to the subsequent counters 203 to 205. Output to
[0032]
The operation of the determination circuit 202 will be described in more detail. The discriminating circuit 202 outputs a signal “1” to the counter 203 every time an output signal “11” indicating that a print dot having a gradation level equal to or larger than the threshold value L2 is output from the comparing circuit 201. Therefore, the counter 203 accumulates the number C1 of print dots having gradation levels equal to or greater than the threshold L2. In FIG. 4, print dots 1, 2, 3, 6, and 13 correspond, and C1 = 5.
[0033]
In addition, the determination circuit 202 outputs a signal “1” to the counter 204 when three or more print dots having a gradation level equal to or greater than the threshold L2 continue. Therefore, the counter 204 accumulates the number C2 of three or more continuous dots. In FIG. 4, print dots 1 to 3 correspond, and C2 = 1.
[0034]
Further, a signal “1” is output to the counter 205 when there are no dots equal to or larger than the threshold value L1 on the left and right of the target print dot, that is, when the print dot is an isolated dot. Therefore, the number C3 of the isolated dots is accumulated in the counter 205. In FIG. 4, print dots 6 and 13 correspond to isolated dots, and C3 = 2.
[0035]
In this way, each of the counters 203 to 205 accumulates the number C1 of high tone print dots, the number C2 of three or more continuous dots and the number C3 of isolated dots among them, and for example, one color toner These values are stored in the memory 211 each time one image is formed. These values are transmitted from the memory 211 to the CPU 124 of the engine controller 12 at a predetermined timing (for example, when the formation of toner images of four colors is completed or when data is requested from the CPU 124), and stored in the memory 127 as necessary. Then, it is used for calculating the remaining amount of toner described later.
[0036]
In the image forming apparatus configured as described above, when a print command is given from an external device such as a host computer, a normal image forming operation for forming an image corresponding to the print command is executed. Specifically, a print command, which is an image formation request from an external device, and image data corresponding to the content of an image to be formed are input to the main controller 11 via the interface 112. The CPU 111 of the main controller 11 separates the received image data for each toner color, develops the image data into image signals having multiple gradation levels, and converts the image signals through the modulation signal generation unit 210 to the engine controller 12. Output to In response to this, the CPU 124 of the engine controller 12 controls each part of the engine EG to execute the above-described series of image forming operations, whereby a desired image is formed on the sheet S. At this time, the image signal switching unit 122 is connected so that an image signal from the main controller 11 is sent to the exposure power control unit 123 in response to a command from the CPU 124.
[0037]
FIG. 5 is a flowchart illustrating a toner counting operation when a normal image forming operation is performed. In this image forming apparatus, the CPU 124 of the engine controller 12 executes the toner counting operation (1) shown in FIG. The remaining amount of toner of the device 4Y and the like is calculated. Here, a method of obtaining the remaining amount of toner in the developing device 4Y will be described using the yellow color as an example, but the operation is the same for other toner colors.
[0038]
In the toner counting operation (1) in FIG. 5, first, the count values C1, C2, and C3 of the print dots by the dot counter 200 are obtained (step S1). Then, a value Ts obtained by multiplying each of these values by a predetermined coefficient is obtained (step S2). That is,
Ts = Kx · (K1 · C1 + K2 · C2 + K3 · C3)
It is. Here, Kx, K1, K2, and K3 are weighting coefficients set in advance for each toner color. In this way, the printing dots are grouped and counted for each continuous dot number, and each number is multiplied by a weighting coefficient and integrated, whereby the amount of toner adhering to the photoreceptor 2 as an image carrier is accurately determined. You can often ask for it. The method of calculating the amount of toner is described in detail in Patent Document 1 mentioned above, and thus the description thereof is omitted here.
[0039]
Next, the remaining toner amount Tr of the developing device 4Y stored in the memory 127 of the engine controller 12 is read (step S3). Then, a value obtained by subtracting the value Ts obtained above from this value Tr is set as a new toner remaining amount Tr (step S4).
[0040]
Further, it is known that in this type of image forming apparatus, a small amount of toner is consumed even when an image forming operation in which a white image, that is, no print dot is formed, is executed. This is because a part of the incompletely charged toner or the oppositely charged toner moves from the developing device 4Y onto the photoreceptor 2 during the image forming operation, or a part of the toner scatters inside the apparatus. When attached to an image, it is visually recognized as fog.
[0041]
In view of the fact that toner is lost due to such a phenomenon, in this embodiment, the drive offset value Tod corresponding to the drive time of the developing device is set. The drive offset value Tod is obtained by multiplying the drive time of the developing device 4Y by a value obtained by an experiment or the like in advance as a toner scattering amount per unit time in the developing device 4Y (step S5). Here, the driving time of the developing device 4Y may be a time during which a developing bias is applied to the developing device 4Y, or a developing roller 40Y that conveys the toner contained in the developing device 4Y to a position facing the photosensitive member 2. And the like can be used. In addition, if the paper size is constant, the developing device driving time per sheet is generally substantially constant. Therefore, the drive offset value Tod may be determined in advance for each paper size and stored in the memory 127. In this case, the drive offset value Tod corresponding to the formed image size may be extracted from the memory 127 in step S5.
[0042]
By subtracting the drive offset value Tod thus obtained from the remaining toner amount Tr obtained in step S4 (step S6), a new remaining toner amount Tr after forming one image is obtained. This value Tr is updated and stored in the memory 127 (step S7).
[0043]
As described above, the sum (Ts + Tod) of the product sum Ts of each dot count value C1 and the like and the weighting coefficient K1 and the like and the drive offset value Tod (Ts + Tod) is the amount of toner consumed when one sheet of image is formed. become. Then, the amount of toner consumed every time one image is formed is calculated and subtracted from the amount of toner remaining immediately before the image formation, thereby obtaining the remaining amount of toner Tr in the developing device 4Y at the present time (at the end of image formation). Can be requested.
[0044]
In this embodiment, the remaining toner amount in the developing device at each time is obtained by subtracting the toner consumption amount for each image from the initial toner storage amount of each developing device. Needless to say, this is in principle equivalent to calculating the total amount of consumed toner by integrating the toner consumption for each image. As described above, in this embodiment, the amount of toner consumed when one sheet of image is formed corresponds to the “first toner amount” of the present invention, and a value obtained by integrating this toner amount is the present invention. Corresponds to the “first integrated value”.
[0045]
Here, in the developing device 4Y or the like which is configured to be detachable from the apparatus main body, before each developing device is detached from the apparatus main body, the toner remaining amount Tr in the developing device determined above is stored in the memory 42Y. It is preferable that the information is stored in the storage device. When the developing device is mounted on the apparatus main body, the remaining amount of toner in the developing device stored in the memory 42Y or the like is read and used as an initial value of the remaining toner amount Tr in the toner counting operation (1). This facilitates the life management of the developing device. Of course, in a new developing device, the loaded amount of toner at the time of shipment of the developing device may be stored.
[0046]
Returning to FIG. 5, in this embodiment, the toner end of the developing device 4Y is determined based on the remaining amount Tr of the toner after image formation. That is, the remaining toner amount Tr obtained as described above is compared with the minimum toner amount Tmin preset for the developing device 4Y (step S8), and the remaining toner amount Tr falls below the minimum toner amount Tmin. If so, it is determined that the toner has run out, and the fact is notified to the main controller 11 (step S9). On the other hand, if the remaining toner amount Tr is equal to or more than the minimum toner amount Tmin, the toner counting operation ends.
[0047]
The minimum toner amount Tmin is the minimum amount of toner required for the developing device 4Y in order to form a good image using the developing device 4Y. That is, if an image is formed while the toner amount in the developing device is less than the value Tmin, there is a high possibility that serious image quality deterioration such as insufficient image density or blurring of the image occurs. Therefore, as described above, when the toner remaining amount Tr falls below the minimum toner amount Tmin, it is determined that the toner is out, so that it is possible to accurately grasp the replacement time of the developing device 4Y.
[0048]
The operation of the main controller 11 when receiving the notification of the toner end from the engine controller 12 is optional. For example, a message notifying the user of the toner end may be displayed on a display (not shown) to prompt the user to replace the developing device. At this time, the image forming operation may be further continued, or the image forming operation may be prohibited. Further, for example, when the developing device determined to be out of toner is other than the black developing device 4K, only the formation of a monochrome image using black toner may be permitted.
[0049]
By the way, in this image forming apparatus, some operations can be executed as operations in the non-normal mode other than the normal image forming operation described above. Then, the amount of toner consumed when each operation is executed is obtained in advance, and as described later, the test pattern offset value Totn (n is 1, 2, 3 in the present embodiment) or the steady offset value Tn (the present embodiment). In the embodiment, n is stored in the memory 127 as 1, 2, 3, 4). Hereinafter, these operations will be described in order.
[0050]
(Image formation condition adjustment operation)
FIG. 6 is a flowchart showing the image forming condition adjusting operation. The image forming condition adjusting operation is for adjusting the image forming conditions and controlling the image density to the target density at a predetermined timing such as immediately after the power of the apparatus is turned on or when the number of image forming sheets reaches the predetermined number. In this image forming condition adjusting operation, a patch image of a predetermined pattern is formed while changing and setting the developing bias as a density control factor affecting the image density in multiple stages (step S11). Next, at the timing when each patch image transferred on the intermediate transfer belt 71 is conveyed to a position facing the patch sensor PS, the respective image densities are detected by the patch sensor PS (Step S12), and the image densities are determined. The correlation with the developing bias is determined. Then, based on the correlation thus obtained, a value of the developing bias is calculated so that the image density matches the target density, and the calculated value is set as the optimum value of the developing bias (step S13).
[0051]
When the optimum value of the developing bias is determined in this way, the image forming is executed while setting the developing bias to the optimum value, so that the image can be formed at the target image density. It should be noted that, as such a density control technique, many techniques have been proposed conventionally, and any technique including these known techniques can be applied to the image forming condition adjusting operation of this embodiment. Here, detailed description is omitted.
[0052]
In the image forming condition adjusting operation, a plurality of patch images are formed as described above. Each patch image only needs to have a size (for example, several cm square) that can be detected by the patch sensor PS, and its pattern is relatively simple, such as a solid image or an image in which dots are regularly arranged. Things. Therefore, for such a patch image, a pattern can be independently created in the engine controller 12 without supplying an image signal from the main controller 11. In this embodiment, the pattern creation module 125 (FIG. 2) provided in the engine controller 12 has a function of creating a pattern as a patch image. That is, in the image forming condition adjustment operation, the CPU 124 outputs a control command to the pattern creation module 125 to output an image signal corresponding to the patch image, and controls the image signal switching unit 122 to output the pattern creation module 125. Is input to the exposure power control unit 123. As a result, an electrostatic latent image corresponding to the patch image pattern is formed on the photoconductor 2.
[0053]
The image forming condition adjusting operation is for adjusting the operating condition of the engine EG to obtain a desired image density, and can be performed independently of the operation of the main controller 11. Therefore, by generating the patch image pattern in the engine controller 12 in this manner, the main controller 11 does not need to be involved in the operation, and during that time, processing of an image to be formed next is executed. Thus, the processing efficiency of the main controller 11 can be improved.
[0054]
Executing the image forming condition adjusting operation also consumes the toner in the developing device. The toner consumption at this time cannot be obtained from the image signal from the main controller 11. Thus, in this embodiment, as shown in FIG. 6, after optimizing the developing bias, the amount of toner consumed in the image forming condition adjusting operation is obtained. Performs a different toner counting operation (2) (step S14).
[0055]
In the image forming condition adjusting operation, since the pattern of the patch image to be formed is known, it is possible to estimate in advance the amount of toner adhering to the photoconductor 2 as the patch image. Therefore, the toner amount is obtained in advance by an experiment, for example, and stored in the memory 127 as the test pattern offset value Tot1. Then, in the toner counting operation (2), every time a patch image is formed, the offset value Tot1 is subtracted from the immediately preceding toner remaining amount to determine the remaining toner amount in the developing device. This is a major difference from the dot counting operation (1) for obtaining the number of print dots from the image signal. The specific procedure of the toner counting operation (2) will be described later with reference to FIG.
[0056]
(Test pattern formation operation)
In this apparatus, as an operation in the non-normal mode, an operation of forming a toner image on the sheet S as a test pattern for a user to visually confirm image quality is executed. This test pattern is also output from the pattern creation module 125. For this reason, the toner consumption amount at the time of executing this operation is also obtained in advance as the test pattern offset value Tot2 corresponding to the test pattern and stored in the memory 127, and the toner count operation (2) shown in FIG. ), The remaining toner amount Tr at the end of the operation is obtained.
[0057]
(Refresh operation)
In this device, a refresh operation is performed as the operation in the non-normal mode. In the developing units 4K, 4C, 4M, and 4Y, the toner is supplied from the built-in toner container to the developing rollers 40K, 40C, 40M, and 40Y, and the toner layers formed on the developing rollers 40K, 40C, 40M, and 40Y are formed. The thickness is configured to be constant by the regulating blade. Note that, in FIG. 1, for convenience, only the regulating blade 43M of the developing device 4M is denoted by a reference numeral. Then, if image formation with a low image occupation ratio (ratio of the number of print dots to the total number of pixels constituting the toner image) continues, the amount of toner staying at the same location in the developing units 4K, 4C, 4M, and 4Y increases. In addition, the possibility that filming, which is a phenomenon in which an external additive of toner or the toner itself adheres to the surface of the developing roller or the regulating blade, increases.
[0058]
Therefore, in this apparatus, at a predetermined timing (for example, prior to execution of the image forming condition adjusting operation), an image having a preset pattern is formed on the photosensitive member 2 to thereby reduce the fatigue of the developing units 4K, 4C, 4M, and 4Y. A refresh operation for restoring the state is performed. Due to the forced consumption of the toner by the refresh operation, the stagnation of the toner in the developing units 4K, 4C, 4M, and 4Y can be eliminated, thereby preventing the deterioration of the image quality due to the occurrence of filming. .
[0059]
The image pattern formed by this refresh operation is equal to the maximum image range that can be formed in the main scanning direction on the photoconductor 2 (the rotation axis direction of the photoconductor 2), the image occupation ratio is a relatively large value, and It is preferable that the print dots are distributed substantially uniformly in the main scanning direction.
[0060]
An image pattern formed on the photoconductor 2 for this refresh operation is also output from the pattern creation module 125. Therefore, the toner consumption amount when executing this operation is also obtained in advance as the test pattern offset value Tot3 corresponding to the test pattern and stored in the memory 127, and the toner counting operation shown in FIG. By executing (2), the remaining amount Tr of the toner at the end of the operation is obtained.
[0061]
FIG. 7 is a flowchart showing the toner counting operation (2). That is, in the toner counting operation (2), first, the test pattern offset value Totn corresponding to the operation is extracted from the memory 127 (step S141). That is, the test pattern offset value Tot1 is extracted for the image forming condition adjustment operation, the test pattern offset value Tot2 is extracted for the test pattern formation operation, and the test pattern offset value Tot3 is extracted for the refresh operation. Is done. As described above, in the toner counting operation (2), the amount of toner adhering to the photoconductor 2 as a toner image is simply given as an offset value according to the image pattern without calculation.
[0062]
If the amount of toner adhering to the photoreceptor 2 as a toner image is thus known, the subsequent operation is the same as the toner counting operation (1) shown in FIG. That is, the remaining toner amount Tr up to the present is read from the memory 127, and the offset value Totn and the drive offset value Todn are subtracted from the values, thereby obtaining the remaining toner amount Tr after the execution of the operation (steps S142 to S146). . If the value Tr is smaller than the minimum toner amount Tmin, it is determined that the toner has run out (steps S147 and S148). As described above, the remaining toner amount Tr after executing the image forming condition adjusting operation, the test pattern forming operation, and the refresh operation is obtained.
[0063]
In the image forming condition adjusting operation, the test pattern forming operation, and the refresh operation, since the image pattern to be formed is determined, the drive offset value Todn is also considered to be constant. Therefore, an offset value Ton corresponding to the sum (Totn + Todn) of the test pattern offset value Totn and the drive offset value Todn is stored in the memory 127 corresponding to each formation pattern, and the formed pattern is used in the toner counting operation (2). May be extracted from the memory 127 and used for calculating the remaining amount of toner.
[0064]
(Toner fogging operation)
In this apparatus, the toner spraying operation is performed as the operation in the non-normal mode. The cleaning blade 51 (FIG. 1) is generally formed of hard rubber or the like, and has a relatively large frictional resistance. Therefore, if the use is started as it is when it is new, the blade may be wound up due to friction with the rotating photoconductor 2. Therefore, the toner is applied to the cleaning blade 51 in advance by a toner spraying operation to reduce the frictional resistance. This toner spraying operation is executed when the apparatus is new or when the cleaning blade 51 is replaced.
[0065]
In this toner fogging operation, toner is supplied from the rotary developing unit 4 to the surface of the photoconductor 2 charged by the charging unit 3. That is, no electrostatic latent image is formed on the photoconductor 2. Therefore, the toner consumption amount when this operation is executed is experimentally obtained in advance as the steady offset value T1, and the value is stored in the memory 127. The toner count in the toner fogging operation is performed according to a toner counting operation (3) in FIG. 8 described later.
[0066]
(Pre-blinking operation)
In this apparatus, as an operation in the non-normal mode, a pre-glazing operation similar to the toner spraying operation is performed prior to the execution of the normal image forming operation. That is, the pre-spraying operation is an operation of attaching a small amount of toner to the surface of the photoconductor 2 in order to prevent abrasion of the photoconductor 2 due to contact with the cleaning blade 51 (FIG. 1). The toner consumption at this time is also obtained in advance and stored in the memory 127 as the steady offset value T2, and the toner count in the pre-flashing operation is also performed according to the toner counting operation (3) of FIG. The toner used in the pre-glazing operation may be only one color, but the yellow color is preferable from the viewpoint that the toner is not conspicuous and does not stain the image formed later. In order to reduce the rotational drive of the developing unit 4 for switching the developing device, it is preferable that the toner color (first color) used first in a normal image forming operation is used. From these facts, it is reasonable to use yellow as the first color in normal image formation.
[0067]
(Idling operation)
In this device, the idle rotation operation is performed as the operation in the non-normal mode. At the time of image formation, toner is supplied to the developing rollers 40K, 40C, 40M, and 40Y from the toner storage units incorporated in the developing devices 4K, 4C, 4M, and 4Y, and the photosensitive members 2 are supplied from the developing rollers 40K, 40C, 40M, and 40Y. , And the electrostatic latent image is visualized to form a toner image. At this time, if the toner in the developing devices 4K, 4C, 4M, and 4Y is unevenly distributed or deteriorates due to insufficient charging, the toner supply to the photosensitive member 2 and the formation of the toner image are not properly performed, and the image quality is reduced. Will decrease. Therefore, in this apparatus, the idle rotation of the developing units 4K, 4C, 4M, and 4Y and the developing rollers 40K, 40C, 40M, and 40Y is performed at a predetermined timing (for example, at a predetermined developing unit driving time or at a predetermined number of printed sheets). By performing the operation and agitating the built-in toner, uneven distribution and deterioration of the toner are prevented.
[0068]
When the idle rotation operation of the developing units 4K, 4C, 4M, and 4Y and the developing rollers 40K, 40C, 40M, and 40Y is performed, a small amount of toner corresponding to the rotation time is generated. Leaking from 4Y is inevitable. Therefore, the toner consumption when the idle rotation operation of the developing units 4K, 4C, 4M, and 4Y is executed is set as the steady offset value T3, and the toner consumption when the idle rotation operation of the developing rollers 40K, 40C, 40M, and 40Y is executed. The amount is experimentally obtained in advance as a steady offset value T4, and these values are stored in the memory 127. The toner counting in the idling operation is performed according to the toner counting operation (3) of FIG. 8 described below.
[0069]
FIG. 8 is a flowchart showing the toner counting operation (3). In this toner counting operation (3), the steady-state offset value Tn corresponding to the operation is extracted from the memory 127, and the extracted steady-state offset value Tn is subtracted from the immediately preceding toner remaining amount, thereby reducing the remaining toner amount in the developing device. I'm asking. That is, in the toner counting operation (3), first, the steady offset value Tn corresponding to the operation is extracted from the memory 127 (step S21). That is, the offset value T1 is extracted in the toner fogging operation, the offset value T2 is extracted in the pre-fogging operation, and the offset value T3 is extracted in the idling operation of the developing units 4K, 4C, 4M, and 4Y, and the developing rollers 40K and 40C are extracted. , 40M and 40Y, the offset value T4 is extracted.
[0070]
The subsequent operation is the same as the toner counting operation (2) shown in FIG. 7, except that there is no drive offset value. That is, the remaining toner amount Tr up to the present time is read from the memory 127, and the extracted steady-state offset value Tn is subtracted from the value to obtain the remaining toner amount Tr after each of the above operations (steps S22 to S24). If the value Tr is smaller than the minimum toner amount Tmin, it is determined that the toner has run out (steps S25 and S26). As described above, the remaining toner amount Tr after executing the toner spraying operation, the pre-spraying operation, and the idling operation is obtained.
[0071]
As described above, in this embodiment, the sum (Totn + Todn) of the test pattern offset value Totn and the drive offset value Todn is the toner amount consumed in the image forming condition adjustment operation, the test pattern formation operation, and the refresh operation. Corresponds to the “second toner amount”. Further, the steady offset values T1, T2, T3, and T4 are the toner amounts consumed in the toner spraying operation, the pre-spraying operation, and the idle rotation operations, and correspond to the “second toner amount” in the present invention. The value obtained by integrating the toner amounts corresponds to the “second integrated value” of the present invention. The difference (Tr0-Tr) between the initial value Tr0 of the remaining toner amount Tr (ie, the amount of toner loaded in the developing device at the time of shipment) and the current remaining amount of toner Tr corresponds to the amount of toner consumed up to that time. This corresponds to “the sum of the first integrated value and the second integrated value” of the present invention.
[0072]
As described above, in this embodiment, when a normal image forming operation based on the image signal from the main controller 11 is performed, the number of print dots is counted based on the image signal, and a predetermined coefficient is added to the count value. The toner consumption is obtained by multiplying and integrating (toner counting operation (1); FIG. 5). On the other hand, when an operation in a non-normal mode, which is not a normal image forming operation, is performed, an offset value obtained in advance as an amount of toner consumed by the operation is set as a toner consumption amount at that time (toner count operation (2 7), toner counting operation (3); FIG. 8). Therefore, the amount of toner consumption can be obtained by an appropriate method corresponding to the operation to be performed, and the amount of toner consumption in each developing device can be accurately obtained. In addition, the amount of toner consumption in each operation mode can be obtained only by calculation, so that the processing is simple.
[0073]
In particular, offset values corresponding to a plurality of operations are stored in the memory 127 as operations in the non-normal mode, and offset values corresponding to operations to be executed are extracted from the memory 127. It is possible to easily and accurately obtain the toner consumption amount for the operation.
[0074]
Then, the amount of toner consumption obtained for each operation is sequentially subtracted from the immediately preceding remaining amount of toner each time each operation is performed, thereby grasping the amount of toner remaining in each developing device at each time. Can be.
[0075]
Incidentally, in such an image forming apparatus, it is desirable that the properties of the toner used are constant in order to stably form the toner image. However, in an actual apparatus, it is known that the image density of the toner image may gradually change while the formation of the toner image is repeated. As can be seen from this fact, the property of the toner is not always constant. Instead, they may change over time.
[0076]
FIG. 9 is a diagram illustrating a change in the particle size distribution of the toner. In a toner used in this type of image forming apparatus, toner particles having various particle diameters are mixed, so that the particle diameter distribution has a certain spread. On the other hand, when an image is formed using a toner having such a particle size distribution, there is known a phenomenon called so-called selective development in which the probability of consumption is different due to the difference in the particle size of the toner.
[0077]
This phenomenon has been experimentally confirmed. FIG. 9A shows how the ratio (volume%) of the small particle size toner having a particle size of 5 μm or less in all the toners in the developing device changes when image formation is repeatedly performed. It shows an example of the result of actual measurement. FIG. 9B shows the change in the volume average particle diameter of the toner remaining in the developing device at that time. As shown in FIG. 9A, as the image formation is performed over a long period of time and the toner consumption increases, the ratio of the small particle size toner gradually decreases. The volume average particle size shown gradually increases. From this, it can be understood that toner having various particle diameters is not consumed uniformly by performing image formation, but toner having a small particle diameter is preferentially consumed initially. As described above, as the image formation is repeated and the toner consumption increases, the degree of variation in the particle size of the toner in the developing device, that is, the particle size distribution of the toner also gradually changes.
[0078]
Further, in this type of image forming apparatus, the image density is controlled by adjusting the image forming condition that affects the image density as described above, but the offset value may change due to the change setting of the image forming condition. There is.
[0079]
For this reason, if the offset values Todn, Totn, and Tn are fixedly set in advance, a discrepancy occurs between the calculated toner consumption and the actual value, and toner replenishment can be performed at an accurate timing. It can be difficult. Therefore, there is a need to establish a technology capable of obtaining the toner consumption amount with higher accuracy regardless of the temporal change of the offset value.
[0080]
In order to solve such a problem and further increase the accuracy of calculating the toner consumption, the offset value may be appropriately changed and set by the CPU 124 according to the change over time of the properties of the toner used and the image forming conditions. Good. Specifically, (1) the offset value is changed and set in accordance with the operation status of the apparatus, (2) the offset value is changed and set in accordance with the usage history of the toner, and (3) the offset value is set in the toner image. By changing and setting according to image forming conditions for forming, it is possible to obtain the toner consumption with higher accuracy. That is, although the properties of the toner used change with time as described above, it can be determined by examining the operation status of the apparatus and the usage history of the toner. Therefore, the change in the properties of the toner over time is made to correspond to the operation state of the apparatus and the usage history of the toner, and the offset value is appropriately changed and set, so that the toner consumption can be accurately obtained. Further, even when the image forming condition changes, the offset value is changed and set according to the change of the offset value, so that the offset value corresponding to the image forming condition is always set, and the toner consumption is accurately obtained. It becomes possible. As described above, in this embodiment, the CPU 124 corresponds to the “offset value setting unit” of the present invention.
[0081]
The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the dot counter 200 is configured as an independent functional block. However, for example, the dot counter may be configured as software executed by a CPU provided in either the main controller 11 or the engine controller 12. The above may be realized.
[0082]
Further, for example, in the above-described embodiment, the CPU 124 of the engine controller 12 reduces the toner consumption based on the count value of the dot counter 200 provided in the main controller 11 and the offset value corresponding to each operation in the non-normal mode. Although the calculation is performed, the invention is not limited thereto. For example, the CPU 111 of the main controller 11 may receive the offset value from the engine controller 12 and calculate the toner consumption. 200 may be provided on the engine controller 12 side.
[0083]
Further, for example, in the above-described embodiment, the remaining amount of toner is obtained every time one image is formed in the normal image forming operation. However, the timing of obtaining the remaining amount of toner is not limited to this. Optional. For example, when there is an image formation request corresponding to a plurality of images, the remaining toner amount may be obtained after forming all the images or every time a predetermined number of images are formed.
[0084]
Further, for example, in the above-described embodiment, the toner end is determined when the remaining toner amount Tr is less than the minimum toner amount Tmin, but the toner consumption amount or the remaining toner amount obtained by calculation is determined. Thus, other controls can be performed. For example, the timing at which the above-described image forming condition adjustment operation is performed may be determined based on the remaining amount of toner. That is, the image forming condition adjusting operation may be executed when the remaining amount of toner reaches a predetermined value. Since the toner characteristics in the developing device gradually change, and the image density may fluctuate accordingly, determining the execution timing of the image forming condition adjustment operation based on the remaining amount of the toner depends on the image density. This is effective in achieving stability. Further, for example, the amount of toner removed from the photoconductor 2 by the cleaning blade 51 of the cleaning unit 5 and collected in a waste toner tank (not shown) of the cleaning unit 5 is estimated from the total amount of consumed toner. The empty capacity of the waste toner tank may be estimated based on the value.
[0085]
In the above-described embodiment, the image forming apparatus is configured to be able to form a full-color image using four color toners of yellow, cyan, magenta, and black. The present invention is not limited to this, and is arbitrary. For example, the present invention can be applied to an apparatus that forms a monochrome image using only black toner.
[0086]
Further, in the above embodiment, the present invention is applied to a printer that receives image data from outside the apparatus and executes an image forming operation based on an image signal corresponding to the image data. An image signal is created inside the apparatus in response to the pressing of the copy button, and a copier that performs an image forming operation based on the image signal or receives image data given via a communication line to execute the image forming operation. It goes without saying that the present invention is also applicable to a facsimile machine to be executed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus of FIG. 1;
FIG. 3 is a block diagram showing a configuration of a dot counter.
FIG. 4 is a diagram illustrating a dot counting procedure.
FIG. 5 is a flowchart illustrating a toner counting operation (1).
FIG. 6 is a flowchart illustrating an image forming condition adjustment operation.
FIG. 7 is a flowchart illustrating a toner counting operation (2).
FIG. 8 is a flowchart illustrating a toner counting operation (3).
FIG. 9 is a diagram illustrating a change in the particle size distribution of the toner.
[Explanation of symbols]
2 photoconductor (image carrier), 11 main controller, 12 engine controller, 111 CPU, 124 CPU (offset value setting means), 125 pattern creating module, 127 memory (storage means), 200 Dot counter

Claims (10)

In an image forming apparatus that forms a toner image on an image carrier based on input image data,
The first integrated value obtained by integrating the first toner amount consumed during the normal toner image forming operation and the second toner amount consumed during the operation in the non-normal mode which is not the normal toner image forming operation An image forming apparatus, wherein an amount of toner consumption is obtained based on a total of the integrated second integrated value. Further comprising a storage means for storing an offset value set in advance corresponding to the operation in the non-normal mode,
The image forming apparatus according to claim 1, wherein the offset value is the second toner amount. The storage unit stores an offset value set corresponding to each of a plurality of operations as the operation in the non-normal mode,
The image forming apparatus according to claim 2, wherein when the operation in the non-normal mode is performed, an offset value corresponding to the operation is extracted from the storage unit, and the extracted offset value is used as the second toner amount. The image forming apparatus according to claim 3, wherein the plurality of operations in the non-normal mode include at least two operations of an image forming condition adjustment operation, a toner spraying operation, a refresh operation, and an idling operation of the toner storage unit. The image forming apparatus according to claim 2, further comprising an offset value setting unit configured to change and set the offset value according to an operation state of the apparatus. The image forming apparatus according to claim 2, further comprising an offset value setting unit configured to change and set the offset value according to a toner usage history. The image forming apparatus according to claim 2, further comprising an offset value setting unit configured to change and set the offset value according to an image forming condition for forming the toner image. The image forming apparatus according to claim 1, wherein the number of print dots forming the toner image is counted based on the image data, and the first toner amount is calculated based on the count value. The image forming apparatus according to claim 1, further comprising a determination function of determining that the toner is exhausted when the calculated toner consumption exceeds a predetermined value. In an image forming apparatus that forms a toner image on an image carrier based on input image data,
Obtaining a first toner amount consumed during a normal toner image forming operation based on the image data;
Obtaining a second toner amount consumed in an operation in a non-normal mode which is not a normal toner image forming operation,
The toner consumption in the image forming apparatus, wherein the total consumed toner amount is obtained based on the sum of a first integrated value obtained by integrating the first toner amount and a second integrated value obtained by integrating the second toner amount. How to calculate the amount.

Images