JP2002162800A - Method and apparatus for detecting toner consumption - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner consumption detection method and device therefor which can accurately detect the toner consumption of each color with a simple construction in a color laser printer. SOLUTION: In each image generation process of C, M, Y and K, the value of printing dots is integrated for one page by a counter 2. In an arithmetic circuit 3, the integrated value is multiplied by a coefficient for every color, and an offset value is added to that. With this constitution, the toner consumption for every color is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an electrostatic latent image on a photoreceptor by a light beam modulated by print data,
In a color image forming apparatus such as a color laser printer which forms an image on a recording sheet by electrostatically adsorbing a color toner as a recording material onto the electrostatic latent image, the consumption of each color toner can be reduced with a simple configuration. It relates to a method and an apparatus frequently obtained.

[0002]

2. Description of the Related Art In an apparatus for forming a color image using a color toner, such as a color laser printer, a user is provided with yellow (Y), magenta (M), cyan (C), and black (K) colors. It is desired to indicate the amount of toner consumed or the remaining amount. For this purpose, it is necessary to detect how much toner of each color has been consumed every time a color image is formed. One method that makes this possible is disclosed in JP-A-9-6195. .

Japanese Patent Application Laid-Open No. 9-6195 discloses a method for detecting toner end, but uses a pulse width modulation circuit (PWM) to print multi-tone dots (which are printed dots). In an image forming apparatus that generates a pulse having a width corresponding to the gradation of the light and emits a laser beam by the pulse to expose the photosensitive member, the width of the pulse generated by PWM is counted, and the counting is performed. A method for detecting the toner consumption based on the value is disclosed.

In the above-mentioned Japanese Patent Application Laid-Open No. 9-6195, although there is no description about color image formation, Y, M, C, K
In the process of forming the image of each color, it can be said that it is possible to detect the consumption amount of the toner of each color by performing the above-described method for each.

It is well known that in recent color image forming apparatuses, each print dot has multiple gradations.

[0006]

However, in order to realize the method disclosed in Japanese Patent Application Laid-Open No. 9-6195, the pulse width generated by PWM must be counted. It will be very difficult. For example, a color image is converted to 1 at a resolution of 600 dpi.
Consider a color image forming apparatus that outputs 10 sheets per minute.
The time for the laser beam to scan the width of one print dot is 23 ns
c, the width of the pulse output from the PWM has a maximum width of only 23 nsec. However, in order to accurately detect the width of a pulse having a very narrow time width in this manner, , A clock generation circuit having a very high frequency and a detection means for detecting the pulse width of the pulse output from the PWM using this clock are required, and the configuration becomes difficult.

Further, there is a problem that the one disclosed in the above-mentioned publication is applicable only to an image forming apparatus using PWM. That is, a color image forming apparatus using a pulse amplitude modulation (PAM) or a hybrid configuration combining a PWM and a PAM in addition to the one using PWM as a pulse modulation method has been proposed. Detection is performed by PA as a pulse modulation method.
This is also a requirement for an apparatus using M and an apparatus using a hybrid configuration.

Therefore, the present invention provides a toner consumption detecting method and apparatus which can accurately detect the toner consumption of each color with a simple configuration and can be applied to any method using a pulse modulation method. It is intended to do so.

[0009]

In order to achieve the above object, a method for detecting a toner consumption according to the present invention is described in claim 1.
As described, the values of the printing dots for each color of the image to be printed in a predetermined unit are integrated, and the integrated value is multiplied by a predetermined coefficient for each color to obtain the consumption amount of the toner recorded on the recording paper. , The offset amount is added thereto, and the total amount of toner consumed at that time is obtained. According to a second aspect of the present invention, there is provided a toner consumption detecting device configured to multiply a counter for integrating print dot values in a predetermined unit and a predetermined coefficient by the integrated value obtained by the counter. And an arithmetic circuit for calculating a toner consumption by adding a predetermined offset amount.

[0010]

Embodiments of the present invention will be described below. First, regarding the toner consumption detection method according to the present invention, in this toner consumption detection method, the print dots of each color of the image to be printed are printed in an appropriate unit period such as one page unit or job unit. Multiply the values,
The integrated value is multiplied by a predetermined coefficient for each color to determine the consumption amount of the toner recorded on the recording paper, and the offset amount is added thereto to determine the total toner amount consumed at that time.

The offset amount is a toner amount consumed irrespective of the exposure time by the laser light, and is a unique value unique to each color image forming apparatus. In other words, it is known that even when a pure white image is printed, some toner is discharged when the photoconductor is cleaned. This is the offset amount. Since the offset amount differs depending on the color, the offset amount is measured for each of the toners of C, M, Y, and K.

Specifically, it is as follows. Now, assume that the values of the print dots are integrated for each page. The color image forming process is performed in the order of C, M, Y, and K.

In this case, first, the values of the print dots for one page of C are integrated. Next, the values of the print dots for one page of M are integrated. Next, the values of the print dots for one page of Y are integrated. Finally, the print dot values for one page of K are integrated.

Then, the integrated value of the print dots for one page of _C is multiplied by a predetermined coefficient K _C for C color, and the offset amount of C color is further added to the multiplied value. It is assumed that the consumed amount of the C color toner thus obtained. Therefore, the consumption amount of the C color toner on the one page is C toner consumption amount = K _C * (integrated value of print dot values) +
(Offset amount of C color).

[0015] M, Y, The same is true for K, the coefficient relating to the M color K _M, coefficients K _Y about the Y color and the coefficients for the K color and K _K, M-color, Y color, K color toner Are as follows.

M toner consumption = K _M * (Integrated value of print dot value) + (M color offset) Y toner consumption = K _Y * (Integrated value of print dot value) +
(Offset amount of Y color) K toner consumption = K _K * (Integrated value of print dot value) +
(Offset amount of K color) The coefficients K _C , K _M , K _Y , and K _K for each color are printed on various images, and the toner amount of each color printed on recording paper at that time is measured. What is necessary is just to determine based on the relationship between the actually measured toner amount and the integrated value of the print dot value of each color of the printed image at that time.

As described above, in this toner consumption detection method, a process of multiplying the values of the printing dots of each color of the print image by a coefficient, multiplying the coefficient by a coefficient, and adding the offset amount thereto may be performed. In addition, since it can be realized with a simple configuration as well as integrating the values of the print dots, the apparatus using PWM as the pulse modulation method can
The present invention can be applied to an apparatus using an AM and an apparatus using a hybrid configuration. That is, this toner consumption detecting method can be applied to any pulse modulation method.

The toner consumption of each color obtained in this way can be variously used. For example, when the color image forming apparatus is connected to a personal computer, the obtained toner consumption is transferred to the personal computer, the toner consumption is integrated and stored in the personal computer, and displayed as a bar graph during printing. You can do so.

Next, an embodiment of a toner consumption detecting device according to the present invention will be described. FIG. 1 is a partial block diagram of an embodiment in which a toner consumption detecting device according to the present invention is applied to a color laser printer, where 1 is a toner consumption detecting device, 2 is a counter, and 3 is an arithmetic unit. Circuit, 1
0 indicates a pulse modulation circuit. Here, it is assumed that the color laser printer is of a type in which developing units of four colors of C, M, Y, and K are arranged around one photoconductor.
In this type of color laser printer, it is well known that one laser beam forms electrostatic latent images of four colors of C, M, Y, and K on one photoconductor. Further, since the overall structure of this type of color laser printer is well known and is not the essence of the present invention, illustration of the photoconductor and the developing device is omitted in FIG.

The operation will be described below. Here, it is assumed that the process of forming a color image is performed in the order of C, M, Y, and K.

The toner consumption detecting device 1 includes a counter 2 and an arithmetic circuit 3. The counter 2 is notified of a control signal from a control unit that performs a color image forming process (not shown). The control signal includes a start signal for notifying the start of the transfer of the print dots and an end signal for notifying the end of the transfer of the print dots. When the counter 2 receives the start signal, the counter 2 starts integrating the values of the input print dots, and upon receiving the end signal, terminates the integration and passes the integrated value to the arithmetic circuit 3.

The arithmetic circuit 3 is notified of a control signal from a control unit (not shown) which performs a color image forming process. The control signals include a color signal indicating the color of the currently performed process, a start signal notifying the start of the transfer of the print dots, and an end signal notifying the end of the transfer of the print dots.

The arithmetic circuit 3 receives the integrated value from the counter 2, and the arithmetic circuit 3 receives the integrated value received from the counter 2 according to a control signal from the control unit and calculates the integrated value of the print dot value of the image of any color. I know there is. Therefore, the arithmetic circuit 3 multiplies the integrated value received from the counter 2 by a coefficient relating to the color and further adds an offset amount of the color to obtain a toner consumption amount of the color in the current printing. The coefficients K _C , K _M , K _Y , and K _{K for} the colors _C , _M , _Y , and _K , and the offset amount of each color are set in the arithmetic circuit 3 in advance.

The pulse modulation circuit 10 generates a pulse for driving a laser beam based on a print dot.
A WM may be used, a PAM may be used, or a hybrid configuration combining them may be used.

The details are as follows. First, a process of forming a C color image is performed. At this time, a start signal is notified from the control unit to the counter 2, and a color signal indicating that a C color image is to be formed is transmitted from the control unit to the arithmetic circuit 3. And a start signal are notified.

Then, transfer of the print dots of the C image is started, and the print dots are input to the counter 2 and the pulse modulation circuit 10. In the pulse modulation circuit 10, pulse modulation is performed based on the value of each print dot, and the generated pulse is supplied to a laser driving unit (not shown in FIG. 1). The counter 2 integrates the values of the input printing dots from the reception of the start signal to the reception of the end signal, and passes the integrated value to the arithmetic circuit 3 upon receiving the end signal.

When the arithmetic circuit 3 receives the integrated value from the counter 2, it recognizes that the integrated value is the integrated value of the values of the print dots of the C image. K _C is multiplied, and an offset amount of C color is added to the multiplied value to obtain a consumption amount of C color toner in the image forming process of C. Accordingly, the consumption amount of the C color toner at this time is as follows: toner consumption amount = K _C * (integrated value of print dot value) + (offset amount of C color) (1).

When the C image forming process is completed in this way, the M image forming process is started next. At this time, a start signal is notified from the control unit to the counter 2 and the arithmetic circuit 3 , A color signal indicating that M color image formation is to be performed and a start signal are notified from the control unit.

Then, transfer of the print dots of the M image is started, and the print dots are input to the counter 2 and the pulse modulation circuit 10. In the pulse modulation circuit 10, pulse modulation is performed based on the value of each print dot, the generated pulse is supplied to the laser driving unit, and the counter 2 receives the start signal from the start signal until receiving the end signal. The values of the printed dots are integrated, and when the end signal is received, the integrated value is passed to the arithmetic circuit 3.

When the arithmetic circuit 3 receives the integrated value from the counter 2, it recognizes that the integrated value is the integrated value of the print dot values of the M image. The multiplication value is multiplied by K _M, and the offset value of M color is added to the multiplied value to obtain the consumption amount of M color toner in the process of forming the M image. Accordingly, the consumption amount of the M color toner at this time is as follows: toner consumption amount = K _M * (integrated value of print dot value) + (M color offset amount) (2).

Next, a Y image forming process is performed.
Subsequently, the K image forming process is performed. Similarly, during these image forming processes, the Y toner consumption and the K toner consumption are obtained. At this time, the consumption amount of the Y color toner and the consumption amount of the K color toner are respectively as follows.

Y color toner consumption = K _Y * (Integrated value of print dot value) + (Y color offset amount) (3) K color toner consumption = K _K * (Integrated value of print dot value) + (Offset amount of K color) (4) As described above, the coefficients K _C , K
_M , K _Y , K _K , and the offset amount of each color can be obtained by experiments. According to the experiment of the present inventor, when one print dot has a 6-bit configuration, K _C = 0.15 × 10 ⁻⁶ (5) K _M = 0.18 × 10 ⁻⁶ (6) K _Y = 0.14 × 10 ^-6 (7) K _K = 0.17 × 10 ^-6 (8). By multiplying the integrated value of the print dot value of each color by these coefficients, the actual value of each color actually printed on the recording paper is obtained. It was confirmed that the toner amount could be determined in the unit of mg. Therefore, if the offset amount of each color is determined in units of mg, the toner consumption amount of each color can be determined in units of mg.

In the above-described example, a case has been described in which the present invention is applied to a color laser printer of a type in which four latent images of four colors of C, M, Y, and K are formed on one photosensitive member by one laser beam. Therefore, the calculation of the toner consumption amount of each color is performed for each forming process of one color image. However, when applied to a so-called tandem type having four sets of photoconductors and developing units, C , M, Y, and K, the toner consumption detecting devices may be provided in the four image forming process systems, respectively. Therefore, it is of course possible to calculate the toner consumption per printing unit. However, it is also possible to calculate the toner consumption in an appropriate unit such as a job unit or a day unit. In that case, the form of the control signal notified to the counter 2 and the arithmetic circuit 3 is
Naturally, it is necessary to appropriately change the unit according to the unit for calculating the toner consumption. In the above embodiment, the arithmetic circuit 1 multiplies the integrated value of the print dot value of each color by a coefficient and adds the offset amount. However, basically, the integrated value of the print dot value of each color can be obtained. Good,
The multiplication of the coefficient and the addition of the offset amount may be separately performed by appropriate means such as software.

The data of the toner consumption of each color obtained by the arithmetic circuit 3 may be given to means for controlling the process of displaying the toner consumption or the remaining toner amount. This makes it possible to display the consumption amount or the remaining amount of the toner of each color in an appropriate graph such as a bar graph on a print screen of a personal computer that provides image data to be printed to the color laser printer. If the display device has an appropriate display function, it is possible to display the consumption amount or the remaining amount of the toner of each color by using the display function.

Next, FIG. 2 shows the results of experiments conducted by the present inventors. FIG. 2 shows the theoretical value of toner consumption when 19 points of various images such as a natural image such as a landscape image, a graphic image including many geometric figures, and an image including both a natural image and a graphic image are printed; FIG. 6 is a diagram illustrating a relationship between an actually measured toner amount and a toner amount actually consumed during printing. In this experiment, one print dot has a 6-bit configuration.

Here, the theoretical value of the toner consumption is defined as
This is the amount of toner consumption of each color obtained by the equations (1) to (4) using the coefficients of the equations (5) to (8). 2A shows the consumption of the Y toner, FIG. 2B shows the consumption of the M toner, FIG. 2C shows the consumption of the C toner, and FIG. 2D shows the consumption of the K toner. In each case, the horizontal axis represents the theoretical value per page, and the vertical axis represents the measured value per page, and the unit is mg. Each of the plotted white circles or black squares in FIGS. 2A to 2D indicates one point of the printed image, respectively, and FIGS. 2A to 2D. Are plotted in each of 19 points.

FIG. 2A shows "y = 1.0003x-0.
0042] is described, which is a straight line equation shown in FIG. 2A when the horizontal axis is x and the vertical axis is y. In addition, FIG. 2A shows “R ² = 0.9768”, which is a correlation coefficient when the correlation between the theoretical value and the measured value is obtained for the 19 plotted points. The same applies to FIGS. 2B to 2D.

2 (a) to 2 (d), the correlation coefficient between the theoretical value and the measured value is 1 for all color toners.
It can be seen that the plotted points are well on one straight line. This means that the theoretical value is in good agreement with the actually measured value. This means that it can be said that, when viewed in units of one page, it can be said that the integrated value of the print dot value is proportional to the toner consumption.

As described above, according to the toner consumption detecting device, the toner consumption of each color can be accurately obtained with a simple configuration, and the device using PWM as a pulse modulation method can be used. , A device using a PAM, a device using a hybrid configuration, or a device that performs pulse modulation by another method.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a toner consumption detection device according to the present invention.

FIG. 2 is a diagram for explaining an experimental result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner consumption detector 2 Counter 3 Operation circuit 10 Pulse modulation circuit

Continued on front page F term (reference) 2H027 DA45 DB01 DB02 DD02 DE02 DE07 EB04 EC06 ED08 EE07 GA50 2H030 AD16 BB02 BB24 BB36 BB38 2H077 DA08 DA15 DA78 DB01 DB10 GA13

Claims (2)

[Claims] 1. The method according to claim 1, further comprising: multiplying a print dot value for each color of an image to be printed in a predetermined unit; ,
A toner consumption detecting method, wherein an offset amount is added thereto, and a total toner amount consumed at that time is obtained. 2. A counter for accumulating a value of a print dot in a predetermined unit, and a calculation for multiplying the integrated value obtained by the counter by a predetermined coefficient and adding a predetermined offset amount to calculate a toner consumption amount. And a circuit for detecting a toner consumption.