JPH08166712A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device which accurately predicts a time when the next toner replenishment is required. CONSTITUTION: A toner use rate per sheet of recording material is obtained from the amount of toner consumed in one copying operation found by a dot counter in the previous copying and the cumulative sheet number of copies since the previous toner-replenishment found by the counter of a controller. The amount of remaining toner is found from the toner use rate, the cumulative number of copies, and toner capacity. Further, the number of days which have been elapsed since the previous toner-replenishment is found, and based on each information, the copyable number of copies and copyable number of days until the toner runs out are obtained. After a power source is turned on, these arithmetic processing 1 are performed again (101), the ordinary copying operation is repeated (102-107), then, the above arithmetic processing 1 is performed for this copying operation (108) and, when the result satisfies such conditions that the amount of remaining toner is not more than a specific amount (109), an informing process, as a warning to a display means, is performed (110).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having means for calculating a residual toner amount from a toner usage rate.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus, a toner sensor or the like is used for detecting the remaining amount of toner. If there is no toner in the toner box, the toner sensor is several K
Vibration is repeated at Hz, and if there is enough toner,
Toner detection is performed by utilizing that the vibration of the piezoelectric vibrator is stopped due to the weight of toner.

[0003]

However, in the above-described method, the remaining amount of toner cannot be detected until the amount of toner becomes small to some extent, and the next toner replenishment time can be predicted in advance. Was difficult.

A first invention according to the present application aims to solve the above problems and provide an image forming apparatus capable of accurately predicting the next toner replenishment time.

In addition to the above object, a second invention of the present application aims to provide an image forming apparatus capable of accurately notifying a user of a toner replenishment time.

Further, in addition to the above object, the third invention according to the present application is capable of reliably notifying the toner replenishment time even in an image forming apparatus connected to an external device such as a printer. The purpose is to provide a device.

In addition to the above object, a fourth invention of the present application aims to provide an image forming apparatus which does not reduce the operating rate of the image forming apparatus.

Further, in addition to the above object, the fifth invention according to the present application provides an image forming apparatus which does not interrupt the image forming operation due to lack of toner during the continuous image forming operation. It is intended to be provided.

In addition to the above object, a sixth invention of the present application aims to provide an image forming apparatus capable of more concretely predicting a toner replenishment time.

Further, in addition to the above-mentioned object, a seventh invention of the present application aims to provide an image forming apparatus capable of informing the toner replenishment time in an easy-to-understand manner.

Further, in addition to the above-mentioned object, the eighth invention of the present application aims to provide an image forming apparatus which can inform the toner replenishment time more easily.

Further, in addition to the above object, the ninth invention of the present application aims to provide an image forming apparatus capable of more specifically notifying the toner replenishment time.

[0013]

According to the first invention of the present application, the above-mentioned object is to expose the surface of a photoconductor on the basis of image information to form an electrostatic latent image, and use a toner of a developing device. In an image forming apparatus that develops the electrostatic latent image to form an image, transfers and fixes it on a recording material, and discharges it, a calculation unit that calculates a toner usage amount based on each image information and a previous toner replenishment time. The means for counting the cumulative number of recording materials, the means for calculating the toner usage rate per recording material from the toner usage amount and the cumulative number of recording materials, and the toner usage rate and the cumulative number of recording materials. This is achieved by having means for calculating the remaining amount of toner based on the remaining amount of toner and means for urging toner supply based on the remaining amount of toner.

According to the second invention of the present application,
The above object is achieved in the first aspect of the present invention, in which the means for urging toner replenishment has a display means for displaying a warning.

Further, according to a third invention of the present application, the above-mentioned object is achieved in the above-mentioned first invention by that the means for urging toner supply has a communication means for performing communication.

According to the fourth invention of the present application,
The above object is achieved in the second invention or the third invention, wherein the means for urging the toner replenishment is to urge the toner replenishment when the toner remaining amount becomes less than a predetermined amount.

Further, according to a fifth invention of the present application, the object is the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate in the second invention or the third invention. The means for urging the toner replenishment is provided by urging the toner replenishment when the number of recording materials becomes smaller than the predetermined number.

According to the sixth invention of the present application,
In the second or third invention, the above object is provided with means for calculating the number of days elapsed from the previous toner replenishment time, the number of elapsed days, the cumulative number of recording materials, the remaining toner amount, and the toner usage. A means for calculating the number of days for which an image can be formed based on the rate and a means for urging toner replenishment, when the period until the number of days for which an image can be formed on the display means becomes shorter than a predetermined period, urges toner replenishment. It is achieved by

Further, according to the seventh invention of the present application, the above object is achieved by displaying the toner remaining amount on the display means in the first invention.

According to the eighth invention of the present application,
According to the first aspect of the invention, there is provided a means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate, and the means for urging toner replenishment displays the number of recording materials on the display means. It is achieved by displaying.

Further, according to a ninth invention of the present application, in the first invention, the object is provided with means for calculating the number of days elapsed from the previous toner replenishment time, and the number of elapsed days and the accumulated number. A means for calculating the number of days for which an image can be formed based on the number of recording materials, the remaining amount of toner, and the toner usage rate is provided. The means for urging toner supply is to display the number of days for which an image can be formed on the display means. To be achieved.

[0022]

According to the first invention of the present application, the toner usage amount is calculated based on each image information, and after the cumulative number of recording materials from the previous toner replenishment time is counted, the toner usage amount and the cumulative amount are accumulated. The toner usage rate per recording material is calculated from the number of recording materials, the remaining toner amount is calculated based on the toner usage rate and the cumulative number of recording materials, and toner is replenished based on the remaining toner amount. Since it prompts, the toner replenishment time is accurately predicted.

According to the second invention of the present application,
In the first aspect of the invention, the means for urging the toner replenishment displays a warning on the display means, so that the user can be accurately notified of the toner replenishment time.

Further, according to the third invention of the present application, in the first invention, the means for urging the toner replenishment needs to communicate with the communication means to replenish the toner to the external device. To inform.

According to the fourth invention of the present application,
In the second invention or the third invention, the means for urging the toner replenishment urges the toner replenishment when the toner remaining amount becomes less than the predetermined amount, so that the toner is not completely exhausted and the operation rate of the apparatus is high. Does not lower.

Further, according to the fifth invention of the present application, in the second or third invention, means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate. Since the means for urging toner replenishment urges toner replenishment when the number of recording materials becomes less than a predetermined number, toner shortage does not occur during continuous image forming operations.

According to the sixth invention of the present application,
In the second invention or the third invention, a unit for calculating the number of days elapsed from the previous toner replenishment time is provided, and based on the number of days elapsed, the cumulative number of recording materials, the remaining amount of toner, and the toner usage rate. Therefore, the means for stimulating toner supply includes a means for calculating the number of days in which image formation is possible, and the means for urging toner supply urges toner replenishment when the period until the number of days image formation is possible in the display means is shorter than the predetermined period. The time is notified more specifically.

Further, according to the seventh invention of the present application, in the first invention, the means for urging the toner replenishment displays the remaining toner amount on the display means, so that the user can clearly determine the toner replenishment time. Recognize.

According to the eighth invention of the present application,
In the first aspect of the present invention, a means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate is provided, and the means for urging toner replenishment displays the number of recording materials on the display means. The user more accurately recognizes the toner replenishment time according to the number of recording materials on which the user intends to form an image.

Further, according to the ninth invention of the present application, in the above-mentioned first invention, means for calculating the number of days elapsed from the previous toner replenishment time is provided, and the number of elapsed days and the cumulative number of recording materials are calculated. The number of days for which an image can be formed is calculated based on the remaining toner amount and the toner usage rate, and the means for prompting toner replenishment displays the number of days for which an image can be formed, so that the user can further Specifically, the toner supply timing is recognized.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 4 is a sectional view showing the structure of the image copying apparatus according to the embodiment of the present invention. In the figure, reference numeral 401 denotes a document feeding device which serves as document feeding means, and the document placed on the document feeding device 1 is moved in accordance with an instruction from the developing and feeding device control unit 501 shown in FIG.
The sheets are fed one by one or two in succession to a predetermined position on the platen glass surface 402. A scanner 404 includes a lamp 403, a scanning mirror 405, and the like, and is a document feeder 4
When the document is placed on the platen glass surface 402 by 01, the main body is reciprocally scanned in a predetermined direction and the reflected light of the document is scanned by the scanning mirror 4
It passes through the lens 408 via 05, 406 and 407, is color separated by an RGB color separation filter (not shown), and forms an image on the image sensor unit 409.

The image signal input to the image sensor unit 409 is sent to the image reader control unit 502 shown in FIG.
An analog image signal color-separated by an RGB separation filter (not shown) and photoelectrically converted is output to the image controller 503.

FIG. 6 is a detailed diagram of the image signal controller 503. In FIG. 6, the image reader controller 502 controls the R
The analog image signal converted into a GB electrical signal is A / D
The converter 601 outputs digital signals (8 signals in this embodiment).
Bit) and then the black correction / white correction unit 602
After the shading correction is performed by, the RGB signals are input to the ND signal generation unit 603. In the ND signal generation unit 603, RGB signals are added and divided into 1/3,

[0034]

## EQU1 ## Dout = (Rin + Gin + Bin) / 3

A luminance signal Dout represented by
It is input to the image processing unit 604. Then, the image processing unit 6
In 04, image processing such as scaling processing for enlarging / reducing the image is performed, and in the dot counter 605, the number of dots of each gradation (4 bits in this embodiment) is counted, and the toner usage amount of the document is measured. After that, the density correction unit 606 sets the brightness-
The density is converted and the density is corrected by the printer and sent to the printer controller 504 of the laser printer.

The operation of each of the above control units is performed by the ROM 50.
6, the R of the CPU circuit unit 505 having the RAM 507 built-in
Based on the control program stored in the OM 506, the overall control is performed. Further, an operation unit 508 is connected to the CPU circuit unit 505, and a mode necessary for image formation is set and a display on the operation panel is performed.

The signal input to the printer control unit 504 as described above is converted into an optical signal by the exposure control unit 410 composed of the laser scanner shown in FIG. 4, and converted into a laser beam based on the image data. Photoconductor 411
Is irradiated.

Reference numerals 412 and 413 denote developing devices, which are the photosensitive members 41.
The electrostatic latent image formed on No. 1 is visualized with a developer (toner) of a predetermined color. Reference numerals 414 and 415 denote transfer paper stacking units, which store and transfer fixed-size transfer paper as a recording material, and are fed to a registration position by driving a feeding roller to form an image formed on the photoconductor 411. The image is re-fed at the timing for aligning the leading edge of the image.

Reference numeral 416 denotes a transfer separation charger, which is a photosensitive member 411.
After the toner image developed on the transfer paper is transferred to the transfer paper, it is separated from the photoconductor 411 and fixed by the fixing unit 417 via the conveyance belt. A paper discharge roller 418 stacks and discharges the transferred paper on which the image has been formed on the tray 420. Numeral 419 is a direction flapper for switching the carrying direction of the transfer-receiving paper on which image formation has been completed to the paper discharge port and the internal carrying path direction to prepare for the multiplex / double-sided image forming process.

The latent image formed on the photoconductor 411 by the irradiation light is developed by the developing device 412 or the developing device 413. The transfer target paper is conveyed from the transfer target paper stacking unit 414 or the transfer target paper stacking unit 415 in synchronization with the latent image timing, and the developed image is transferred to the transfer unit 416. The transferred image is fixed onto the transfer paper by the fixing unit 417, and then discharged from the paper output unit 418 to the outside of the apparatus.

During double-sided recording, after the transfer paper has passed the paper discharge sensor 419, the paper discharge roller 418 is rotated in the direction opposite to the paper discharge direction. At the same time, the flapper 421 is raised upward to transfer the copied transfer paper to the transport path 42.
2, 423 and stored in the intermediate tray 424. At the time of the next back surface recording, the transfer target paper stored in the intermediate tray 424 is fed and the back surface is transferred.

During multiple recording, the flapper 421 is raised upward so that the copied transfer paper is conveyed to the conveying paths 422, 42.
It is stored in the intermediate tray 424 via the third transport path. In the next multiple recording, the transfer target paper stored in the intermediate tray 424 is fed, and multiple transfer is performed.

In the apparatus of this embodiment, an image is formed as described above, but a patch of a toner image of about 1 cm square is formed on the photoconductor 411 between each sheet of the image copying operation, and this patch is formed on this patch. The density is adjusted based on this. Hereinafter, this density adjustment will be described.

FIG. 7 is an explanatory view of a part of the image copying apparatus according to this embodiment. 701 is a display unit, 702 is a timer I
C and 703 are communication circuits, 704 is a high voltage controller, and 705 is a controller.

The laser light emitted from the laser unit 706 passes through the paths 707, 708, 709 and is applied to the photoconductor 411.

Thereafter, the patch density sensor 714 measures the density of this patch, and when the density of this patch is lower or higher than a predetermined density, the high voltage controller 704 controls the primary charger 710 and the developing device 412. The high voltage of the transfer charger 416 is controlled.

In this embodiment, the controller 7
From 05, the toner replacement timing is detected. Hereinafter, the toner replacement timing detection process of this embodiment will be described with reference to FIGS.

First, when the power is turned on, a calculation process 1 for calculating the remaining amount of toner, the number of sheets that can be copied, and the number of days is performed (step 101).

In the arithmetic processing 1, the date and time when the power is first turned on is first obtained from the timer IC 702 (step 2).
01). This is used to calculate the number of days that have passed since the previous toner supply date and time. The last toner supply date and time is the toner cartridge 71 shown in FIG.
Since the switch 717 is reset when 5 is replaced, the date and time is stored in the controller 705.

Next, from the toner amount of the toner cartridge calculated last time, the toner usage rate, and the cumulative number of copies,
The following formula,

[0051]

[Formula 2] (toner remaining amount) = (toner amount of toner cartridge) − {(toner usage rate) × (cumulative number of copies)}

The remaining toner amount is calculated by (step 2
02).

The toner usage rate and the cumulative number of copies are calculated by the calculation process 2 performed in the previous toner replacement time detection process.
The value calculated in (step 104) is stored in the controller 705.

In the calculation process 2, as shown in FIG. 3, the dot counter 605 in FIG. 6 obtains the toner usage amount which is the consumption amount of toner consumed in one copy operation (step 301), and then, The toner usage rate is calculated and updated for each copy operation from the toner usage amount and the cumulative number of copies from the previous toner replenishment time stored in advance as described above (step 302).

[0055]

[Equation 3] {(toner usage rate before one turn) × (cumulative copy number) + (toner usage amount)} / (cumulative copy number +
1)

Then, the cumulative number of copies is incremented (step 303) and the arithmetic processing 2 is ended.

Based on the toner usage rate from the previous toner replenishment time and the cumulative number of copies thus obtained, the remaining toner amount immediately after the power is turned on is calculated, and then the previous toner replenishment time and the above-mentioned Thus, the number of days elapsed from the previous toner replenishment time is calculated from the current date and time obtained in step 201 (step 203). Then, from the number of days elapsed thus obtained and the cumulative number of copies up to the present time obtained in the arithmetic processing 2 as described above,

[0058]

[Equation 4] (Cumulative number of copies) / (Elapsed days)

Then, the number of copies per day is calculated (step 204), and the following equation is calculated from the present remaining toner amount obtained as described above and the toner usage rate up to the present.

[0060]

[Equation 5] (remaining amount of toner) / (toner usage rate)

Then, the number of sheets that can be copied is calculated (step 205). In other words, the number of copies that can be made refers to the number of copies that can be made from the present time until the toner is completely consumed.

Further, using the above-mentioned number of copies per day,

[0063]

[Equation 5] (toner remaining amount) / ((toner usage rate) × (number of copies))

Thus, the number of copyable days from the present time until the toner is completely consumed is calculated (step 20).
6).

The toner remaining amount, the toner usage rate, the cumulative number of copies, and the last toner replenishment time obtained as described above are stored in the memory of the controller 705, the toner cartridge 715 is replaced, and the switch 717 is operated. When reset, these values are initialized.

As described above, when the remaining amount of toner, the number of copyable sheets and the number of copyable sheets up to the present are obtained by the arithmetic processing 1, the preprocessing step (process timing control, etc.) is performed (step 102). When the copy button is turned on and the copy operation is started (step 10
3) The above-described calculation process 2 is performed to update the toner usage rate and the cumulative number of copies (step 104).

Then, the copy operation is performed (step 1
05), after the high pressure control is performed (step 106), these processes are repeated until the copy is completed (step 105).
~ 107).

Thereafter, the calculation process 1 is performed again (step 108), the remaining toner amount, the number of sheets that can be copied, and the number of days that can be copied after this copying operation are obtained, and it is determined whether or not the predetermined condition is satisfied (step). 10
9).

The predetermined condition is that the toner remaining amount is less than a certain specified value. Alternatively, conditions may be set such that the number of days until the toner runs out is less than a specified value. If this predetermined condition is satisfied, notification processing is performed (step 1
10). This notification processing may be performed by displaying on the display unit 701 in FIG. 7 that the toner is low, or by displaying the above-described number of copyable sheets, the number of copyable days, and the like. Similarly, a message may be sent from the communication circuit 703 of FIG. 7 to a service person or administrator at a remote place through a LAN or a public line.

Further, although the notification is given under the predetermined condition in the present embodiment, the value obtained by the above calculation is always used as the toner remaining amount, the number of remaining copies, and the next toner supply scheduled month even if the predetermined condition is not satisfied. Format (Fig. 8 (a), (b), (c))
May be displayed or communication may be performed.

Further, since the number of sheets that can be copied is calculated by the operation before the copy button is pressed, if a plurality of sheets exceeding the number of sheets that can be copied is to be copied, the number of sheets that can be copied must be set before starting the copy operation. Notification processing may be performed.

[0072]

As described above, the first aspect of the present application
According to the invention, the toner usage amount is calculated based on each image information, the cumulative number of recording materials from the previous toner replenishment time is counted, and one recording material is calculated from the toner usage amount and the cumulative recording material number. The toner usage rate per hit is calculated, the remaining toner amount is calculated based on the toner usage rate and the cumulative number of recording materials, and toner replenishment is prompted based on the remaining toner amount. Can be predicted.

According to the second invention of the present application,
In the first aspect of the invention, the means for urging the toner replenishment displays a warning on the display means, so that the user can accurately know the toner replenishment time.

Further, according to the third invention of the present application, in the above-mentioned first invention, the means for urging the toner replenishment needs to communicate with the communication means to replenish the toner to the external device. Can be notified.

According to the fourth invention of the present application,
In the second invention or the third invention, the means for urging the toner replenishment urges the toner replenishment when the toner remaining amount becomes less than the predetermined amount, so that the toner is not completely exhausted and the operation rate of the apparatus is high. Can be prevented.

Further, according to the fifth invention of the present application, in the second invention or the third invention, means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate. Since the means for urging toner replenishment urges toner replenishment when the number of recording materials becomes less than a predetermined number, it is possible to prevent toner shortage during continuous image forming operations.

According to the sixth invention of the present application,
In the second invention or the third invention, a unit for calculating the number of days elapsed from the previous toner replenishment time is provided, and based on the number of days elapsed, the cumulative number of recording materials, the remaining amount of toner, and the toner usage rate. Therefore, the means for stimulating toner supply includes a means for calculating the number of days in which image formation is possible, and the means for urging toner supply urges toner replenishment when the period until the number of days image formation is possible in the display means is shorter than the predetermined period. The time can be notified more specifically.

Further, according to the seventh invention of the present application, in the above-mentioned first invention, the means for urging toner replenishment displays the remaining toner amount on the display means, so that the user can clearly determine the toner replenishment time. You can know

According to the eighth invention of the present application,
In the first aspect of the present invention, a means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate is provided, and the means for urging toner supply displays the number of recording materials on the display means. The user can know the toner replenishment time more accurately according to the number of recording materials on which he or she intends to form an image.

Further, according to the ninth invention of the present application, in the above-mentioned first invention, means for calculating the number of days elapsed from the previous toner replenishment time is provided, and the number of elapsed days and the cumulative number of recording materials are calculated. The number of days for which an image can be formed is calculated based on the remaining toner amount and the toner usage rate, and the means for prompting toner replenishment displays the number of days for which an image can be formed, so that the user can further Specifically, it is possible to know the toner supply timing.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating an image forming operation control and a toner replacement timing detection control according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a calculation process of remaining toner amount and the like according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a toner usage rate calculation process and the like according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a controller unit according to an embodiment of the present invention.

FIG. 6 is a detailed view of the image signal control unit of FIG.

FIG. 7 is a diagram illustrating a part of the image forming apparatus.

FIG. 8 is a diagram showing a display example of the present embodiment.

[Explanation of symbols]

411 Photoconductor 412, 413 Developing device 605 Dot counter (arithmetic means for computing toner usage amount based on each image information) 701 Display unit (display means) 703 Communication circuit (communication means) 705 Controller (from previous toner replenishment time Means for counting the cumulative number of recording materials, a means for calculating the toner usage rate per recording material from the toner usage amount and the cumulative number of recording materials, and the remaining toner amount based on the toner usage rate and the cumulative number of recording materials. Calculating means, means for urging toner replenishment based on the remaining toner amount, means for calculating the number of recording materials on which images can be formed based on the remaining toner amount and toner usage rate, and the number of days elapsed from the previous toner replenishment time Means, means for calculating the number of days on which an image can be formed, based on the number of elapsed days, the cumulative number of recording materials, the remaining amount of toner, and the toner usage rate)

Claims (9)

[Claims] 1. A photosensitive member surface is exposed based on image information to form an electrostatic latent image, and the electrostatic latent image is developed by toner of a developing device to form an image, which is transferred / fixed onto a recording material. In an image forming apparatus that discharges at least, a calculation unit that calculates the toner usage amount based on each image information, a unit that counts the cumulative number of recording materials from the previous toner replenishment time, the toner usage amount and the cumulative recording material Means for calculating the toner usage rate per recording material from the number of sheets, means for calculating the toner remaining amount based on the toner usage rate and the cumulative number of recording materials, and toner replenishment based on the toner remaining amount And an image forming apparatus having means for urging the user. 2. The image forming apparatus according to claim 1, wherein the means for urging toner supply has a display means for displaying a warning. 3. The image forming apparatus according to claim 1, wherein the toner replenishing means includes a communication means for performing communication. 4. The image forming apparatus according to claim 2, wherein the toner replenishment urging means urges toner replenishment when the remaining amount of toner becomes less than a predetermined amount. 5. A means for calculating the number of recording materials capable of forming an image based on the remaining toner amount and the toner usage rate, and means for urging toner replenishment is provided when the number of recording materials becomes less than a predetermined number. The image forming apparatus according to claim 2, wherein the toner supply is promoted. 6. A number of days on which an image can be formed based on the elapsed days, the cumulative number of recording materials, the remaining toner amount, and the toner usage rate, comprising means for calculating the elapsed days from the previous toner replenishment time. 5. The toner replenishing means for urging toner replenishment is urged to replenish toner when the period until the number of days on which the image can be formed on the display means becomes shorter than a predetermined period. The image forming apparatus described. 7. The image forming apparatus according to claim 1, wherein the toner replenishing means displays the remaining toner amount on the display means. 8. A means for calculating the number of recording materials capable of forming an image based on the remaining amount of toner and a toner usage rate, and the means for urging toner replenishment displays the number of recording materials on a display means. The image forming apparatus according to Item 1. 9. A number of days that an image can be formed based on the elapsed days, the cumulative number of recording materials, the remaining toner amount, and the toner usage rate. The image forming apparatus according to claim 1, further comprising: a unit for calculating the toner supply amount, and the unit for urging toner replenishment displays the number of days on which image formation is possible on the display unit.