JP2001235985A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately judge the service life of a development unit and a developing device. SOLUTION: A CPU 3 displays a message for urging a user to exchange a development unit 26 on a display part 11, when the speed of revolution of a photoreceptor drum 22 counted by a counter 8 becomes equal to or more than a prescribed counted value of service life, or when the number of printing dots in printing data for driving a LED head 2 counted by a counter 9c becomes equal to or more than a prescribed counted value of service life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus, and more particularly, to an image recording apparatus capable of appropriately detecting the life of a developing unit and preventing deterioration of print quality.

[0002]

2. Description of the Related Art In an image recording apparatus such as an electrophotographic printer, a photoconductor drum having a photoconductor such as an organic thin film is charged, and the surface of the photoconductor drum is irradiated with recording light generated by an LED or the like to form an electrostatic image. After the latent image is formed, toner is adhered to the photosensitive drum to develop the electrostatic latent image, the toner image formed by the development is transferred to paper, and the transferred toner image and paper are further applied while applying heat. The toner image is fixed on the paper by pressing.

In such an electrophotographic printer or the like, a predetermined amount of toner is stored in a predetermined portion (hopper portion) in a developing device in consideration of the convenience of toner replenishment or replacement. .

[0004] Since printing cannot be performed if the toner as the developer runs out, the life of the developing device is reached when all the stored toner is consumed. If the amount is less than the amount, the printed image becomes faint or toner adheres to the non-printed portion, so that the print quality is extremely deteriorated. Thus, the life of the developing device is substantially reduced.

[0005] Therefore, in a conventional electrophotographic printer or the like, the remaining amount of toner is detected, and when the remaining amount of toner is less than a predetermined amount, a warning is issued by a warning sound, a warning display, or the like. Before the print quality is reduced, the user can easily determine the life of the developing device.

As a method for detecting the remaining amount of toner, a method for mechanically detecting a load at the time of stirring the toner,
There is known a method of monitoring data for driving an ED head, counting the number of dots to be printed, detecting the amount of toner consumed, and detecting the remaining amount of toner.

Further, in the above-described conventional electrophotographic printer and the like, if the photosensitive drum is deteriorated, the quality of a printed image is reduced. Therefore, the life of the photosensitive drum is detected, and a warning is issued when the life of the photosensitive drum is reached. A warning is issued by a sound, a display, or the like, so that the user can easily determine when to replace the photosensitive drum.

As a method for detecting the life of the photosensitive drum, the number of rotations of the photosensitive drum is counted, and when the number of rotations exceeds a predetermined number of rotations (lifetime rotation number), the life of the photosensitive drum is determined. There are known ways to do this.

[0009]

However, when the toner deteriorates, the fluidity decreases, and the load at the time of stirring the toner increases. Therefore, as described above, in the method of mechanically detecting the load at the time of stirring the toner, When the toner deteriorates, the amount of the remaining toner is detected as being larger than the actual amount.

In an electrophotographic printer, the amount of toner adhered per dot is not constant due to the setting of print density and the like, and the amount of toner consumption varies depending on the printing condition. In some cases, accurate toner consumption cannot be detected only by counting the number of dots.

Incidentally, as a recent trend, a developing unit in which a photosensitive drum and a toner tank are integrated is becoming mainstream. If the life of such a developing unit is detected only by the life of the photosensitive drum based on the rotation speed of the photosensitive drum or the like, the life of the developing unit due to toner consumption and deterioration is not considered at all. For this reason, if the toner life has come due to consumption or deterioration of the toner before the life of the photosensitive drum, the life of the developing unit cannot be properly detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide an image recording apparatus capable of appropriately determining the life of a developing unit or a developing device in accordance with the actual situation. I do.

[0013]

An image recording means according to the present invention comprises a photosensitive drum for forming an electrostatic latent image corresponding to recording light, a storage section for storing the toner, and a toner stored in the storage section. An integrally replaceable developing unit including a developing roller for supplying the photosensitive drum, first detecting means for detecting the rotation speed of the photosensitive drum, and data for forming an electrostatic latent image on the photosensitive drum A second detector for counting the number of dots in the medium, and a threshold value corresponding to one of the number of rotations of the photosensitive drum detected by the first detector and the number of dots detected by the second detector. In the above case, there is provided a determining means for generating a warning signal, and a warning means for issuing a warning in response to the warning signal from the determining means.

According to another aspect of the present invention, there is provided an image recording apparatus, comprising: a photosensitive drum for forming an electrostatic latent image corresponding to recording light; a hopper for accommodating toner; and a lower part of the hopper. A supply mechanism having a developing roller for supplying the toner to the photosensitive drum, and an integrally replaceable developing device for developing an electrostatic latent image on the photosensitive drum, and detecting whether the hopper is empty Detecting means for counting the number of dots in the data for forming an electrostatic latent image on the photosensitive drum, and counting when the detecting means detects that the hopper is empty. Calculating means for calculating the consumption amount of toner per dot according to the count value of the means, calculating the life count based on the consumption amount, and detecting that the hopper is empty by the detection means. of When the count number of the unt means is equal to or greater than the life count number calculated by the calculation means, a determination means for generating a warning signal and a warning means for issuing a warning according to the warning signal from the determination means are provided. It is characterized by.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an apparatus such as an electrophotographic printer, a facsimile machine, a copying machine, or a multifunction peripheral thereof, in which a toner cartridge containing toner as a developer and a photosensitive drum are integrated. The present invention can be applied to a printing apparatus using the developed developing unit. First embodiment

FIG. 1 is a block diagram showing a configuration of a main part of an electrophotographic printer according to a first embodiment of the present invention.

In the electrophotographic printer according to the first embodiment, the number of rotations (drum count) of the photosensitive drum and the LE
Number of dots actually printed by D head (dot count)
, The life of the developing unit having the photosensitive drum and the toner cartridge is appropriately determined. Here, the drum count means the number of rotations of the photosensitive drum during a printing operation or a cleaning operation, and the dot count is
It means the number of effective dots (dots actually printed) at the time of printing.

As shown in FIG. 1, the electrophotographic printer includes a printer control unit 1 for controlling operations such as printing, and an L for generating a recording light in accordance with control from the printer control unit 1.
An ED head 2, and a photosensitive drum described below for forming an electrostatic latent image according to recording light from the LED head 2;
A high-voltage power supply 51 for charging the photosensitive drum, a charging roller and a transfer roller described below, a power supply 52 for supplying power to a heater and a cooling fan for heating a fixing roller described below,
A thermistor 53 for detecting the temperature of the heater; a toner sensor 54 for detecting the amount of toner; and a display unit 11 for displaying the state of the electrophotographic printer, a message for the user, and the like.
Etc. are provided.

The printer control unit 1 includes a CPU 3, a memory 4, an EEPROM 5, a gate array (G / A) 6,
Drivers 7a, 7b, 7 for driving a printing motor (main motor) 41, a conveying motor (registration motor) 42, and paper feeding motors (first and second motors) 43, 44.
c, 45, a counter 8 for counting the number of rotations of the photosensitive drum (drum count), and a dot counter 9 for counting the number of printed dots (dot count).

FIG. 2 is a side sectional view showing the structure of the printing mechanism of the electrophotographic printer.

This electrophotographic printer uses a developing unit 26 in which a toner cartridge 31 containing toner and a photosensitive drum 22 are integrated in consideration of convenience at the time of replacement. The developing unit 26 is replaced by the user when it is determined that the life thereof has expired as described later.

As shown in FIG. 2, the developing unit 26
Is provided with a cleaning roller 27, a charging roller 28, a developing roller 30 and the like provided around the photosensitive drum 22. When the developing unit 26 is mounted on the electrophotographic printer, the photosensitive drum 22 is located at a position close to the LED head 2.

The electrophotographic printer has a paper tray 12 provided at the lower part of the housing, and a paper discharge unit 13 provided at the upper surface of the housing. Paper tray 12, paper discharge unit 1
3 are provided at both ends of the transport path 14.
Along the line 4, a hopping roller 16 for feeding out the sheet 15 from the sheet tray 12, a registration roller 17, a sheet sensor 18, a transfer roller 19, a heat roller 20, and two discharge rollers 21 are provided. The transfer roller 19 is provided to face the photosensitive drum 22,
0, the pressure roller 2 facing each of the discharge rollers 21
3, 24 and 25 are provided.

The photosensitive drum 22 is, as shown in FIG.
It is composed of a base material 22a formed of a conductive metal, for example, an aluminum material, and a charged layer 22b formed by applying a photoconductive material to the base material 22a.

FIG. 4 shows the dot counter 9 in FIG.
FIG. 3 is a diagram showing a more detailed configuration of FIG.

As shown in FIG. 4, print data (DATA) and a clock (CLK) for supplying the print data DATA are supplied to the LED head 2 via a gate array (G / A) 6. ), A signal (LOAD) for instructing holding of print data, control signals (STB1 to STB4) for driving a large number of LED elements constituting the LED head 2 for each group, and the like.

The dot counter 9 uses the clock CL described above.
An inverter 9a for inverting K, and an inverter 9a
For calculating the logical product of the output of the print data and the above-described print data DATA
An ND gate 9b and a counter 9c for counting the output (count CLK) of the AND gate 9b and supplying the count value to the CPU 3 are provided.

This counter 9c counts the total number of black dots, that is, the total number of print dots in the print data after the development unit 26 is replaced. The count value of the counter 9c is held in the EEPROM 5 or the like by the CPU 3 or the like each time printing of one sheet is completed, and is set to the value held before the power was turned off when the power was turned on. .

The print data DATA is supplied to the LED head 2 as serial data in synchronization with the clock CLK. Since the print data DATA corresponds to the dots to be actually printed, the number of dots actually printed can be obtained by monitoring the print data DATA.

FIG. 5 is a time chart showing waveforms of one line of print data and the like during printing.

LSYNC in FIG. 5 indicates a synchronization signal for each line separately supplied to the LED head 2.

As described above, the output (count CLK) of the AND gate 9b is the logical product of the inverted output of the clock CLK and the print data DATA.
As shown in (a), for example, “1” corresponding to a black dot
Is output corresponding to the print data DATA.

Accordingly, as shown in FIG. 5, the output of the counter 9c for counting the count CLK is the total number of black dots printed since the developing unit 26 was replaced.

The electrophotographic printer configured as described above executes a printing process in response to a print instruction from an external device such as a personal computer, similarly to a conventional electrophotographic printer.

When the execution of the printing process is started, C in FIG.
The PU3 firstly receives the first signal via the G / A 6 and the driver 7c.
Of the hopping roller 16 in FIG.
Is rotated to feed out one sheet 15 from the sheet tray 12. As a result, the paper is fed to the transport path 14. When the paper sensor 18 detects the paper 15,
The CPU 3 drives the main motor 41 via the G / A 6 and the driver 7a to drive the registration roller 17, the transfer roller 19, the heat roller 20, the discharge roller 21, the photosensitive drum 22, the cleaning roller 27, and the charging roller in FIG. 2
8. The developing roller 30 is rotated.

The CPU 3 rotates each roller and applies a high voltage corresponding to each of the transfer roller 19, the cleaning roller 27, the charging roller 28, and the developing roller 30 to the high voltage power supply 51. Photoconductor drum 22
A negative charge is supplied to the charged layer 22b on the surface of the substrate by the charging roller 28 to which a negative voltage is applied, and the surface is uniformly charged.

The CPU 3 sequentially supplies the print data supplied line by line from an external device to the LED head 2, and instructs the generation of recording light. Thus, an electrostatic latent image corresponding to the recording light from the LED head 2 is formed on the uniformly charged surface of the photosensitive drum 22. This electrostatic latent image is developed with the toner supplied from the developing roller 30.

On the other hand, a positive charge is supplied to the sheet 15 from the transfer roller 19, and when the sheet 15 reaches a position facing the toner image, the toner images on the photosensitive drum 22 are sequentially transferred to the sheet 15. You. The toner image transferred to the sheet 15 is fused to the sheet 15 by the heat roller 20 and the pressure roller 23. When the toner image is welded, paper 15
Are sequentially discharged to the paper discharge unit 13 by the discharge rollers 21.

In such a printing process, the dot counter 9 in FIGS. 1 and 4 counts the number of dots actually printed by the counter 9c.
As described above, the value of the counter 9c is
6 is the total number of black dots printed after the replacement (the number of printed dots).

The counter 8 shown in FIG.
The number of rotations of the photosensitive drum 22 since the developing unit 26 was replaced in accordance with the drive output of a is counted.
In this drum count, for example, the number of motor steps, which is the drive output of the driver 7a for one rotation of the drum, is counted as one rotation of the photosensitive drum. The count value is supplied to the CPU 3 as in the output of the counter 9c.

The CPU 3 of the above-mentioned printer control unit 1 determines the total number of the black dots, the photosensitive drum in the printing operation, cleaning operation, etc. every time a predetermined unit of the above-described printing processing, for example, one page is completed. The life of the developing unit is determined based on the number of rotations.

FIG. 6 is a flowchart showing such a life determining process.

In step S1, the CPU 3 waits for the end of a predetermined unit of the printing process, and when the printing process of the predetermined unit ends, proceeds to the subsequent step S2.

In step S2, the CPU 3 refers to the count value (dot count) of the counter 9c in FIG. 4 and determines in step S3 whether the dot counter has reached the preset life count value. Determine whether or not. If the dot count has reached the life count value, it is determined that the life of the developing unit 26 is reached, and the process proceeds to step S6.
If the dot count has not reached the life count value, the process proceeds to the subsequent step S4.

In step S4, the CPU 3 refers to the count value (drum counter) of the counter 8 and determines in a succeeding step S5 whether or not the drum counter has reached a preset life count value. If the drum count has reached the life count value, it is determined that the life of the developing unit 26 has expired, and the process proceeds to step S6. If the drum count has not reached the life count value, the process proceeds to step S6.
The process returns to 1 and waits for the end of the next predetermined unit of the printing process.

In step S6, the CPU 3 displays a message prompting the user to replace the developing unit 26 on the display unit 11.
Is displayed, and the process ends.

Thus, the user can see the display on the display unit 11 and recognize that the life of the developing unit 26 has come to an end.

In a conventional electrophotographic printer or the like, the life of the developing unit 26 is determined only by the rotation speed of the photosensitive drum 22, and therefore, depending on the printing situation, the actual consumption of the toner may be smaller than the assumed toner consumption. When the consumption of toner is large, there is a possibility that the remaining amount of toner becomes insufficient before the life of the developing unit 26 is detected based on the number of rotations of the photosensitive drum, and the quality of printing deteriorates.

On the other hand, in the electrophotographic printer according to this embodiment, there is a correlation between the number of rotations (drum count) of the photosensitive drum indicating the wear of the photosensitive layer of the photosensitive drum 22 and the toner consumption. Since the life of the developing unit 26 is determined based on the count value (dot count) of the number of dots printed on the developing unit 26, it is possible to detect an appropriate life of the developing unit 26 in accordance with a use situation and the like. Appropriate print quality can be ensured until the replacement time of the printer. Second embodiment

FIG. 7 is a block diagram showing a configuration of a main part of an electrophotographic printer according to a second embodiment of the present invention.
Among the components shown in FIG. 7, the same or corresponding components as those in FIG. 1 described above are denoted by the same reference numerals as those in FIG.

In the first embodiment described above, the life of the developing unit is determined based on the dot count and the drum count. However, in the electrophotographic printer according to the second embodiment, the remaining amount of toner is determined. The toner consumption is accurately measured based on the detection, the toner consumption corresponding to the number of dots actually printed (dot count), and information such as the number of printed sheets and the number of rotations of the photosensitive drum (drum count). Thus, the life due to the consumption of the toner is accurately determined.

For this reason, this electrophotographic printer is designed as shown in FIG.
As shown in FIG. 7, in addition to the configuration of FIG. 1, a toner sensor 54 for detecting that the remaining amount of toner has become equal to or less than a predetermined amount is provided. The electrophotographic printer also includes a paper sensor 18 and a counter 56 that counts the number of prints based on the detection output of the paper sensor 18.

FIG. 8 is a sectional side view showing the structure of a printing mechanism of the electrophotographic printer. 8 that are the same as or correspond to the components in FIG. 2 described above are denoted by the same reference numerals as in FIG.

In this electrophotographic printer, a developing device 26A provided separately from the photosensitive drum 22 is used instead of the integrated developing unit 26 in FIG. When the life of the developing device 26A expires as described later,
It is replaced independently of the photosensitive drum 22 and the like.

A hopper 31A for storing toner is provided above the developing device 26A, and a mechanism 31B for storing the developing roller 30 and the like is provided below the hopper 31A.

The hopper 31A in the developing device 26A is provided with a stirring bar 55 for stirring the toner. The rotation of the stirring bar 55 is attached to one end of the stirring bar 55 as shown in FIG. Is detected as a detection output of the Hall element 59 facing the magnet 58 that has been applied. 7 detects the remaining amount of toner based on the detection output of the Hall element 59.

The stirring bar 55 receives the driving force from the main motor described above, rotates at a constant speed for a half cycle, and transmits the driving force only to the portion where the toner remains in the other half cycle. Specifically, as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-76646, the driving force from the main motor 41 is supplied to the stirring bar 55 for one half rotation during one rotation, but the remaining half rotation is provided. No driving force is supplied in minutes.

For this reason, when the toner is present in the hopper 31A, the toner is decelerated when the toner reaches the toner even if the stirring bar 55 falls even if the stirring bar 55 falls during a half-period period in which the driving force is not supplied to the stirring bar 55. When the hopper 31A is empty, the agitating bar 55 falls freely to the lowermost position, so that the movement of the agitating bar 55 depends on the presence or absence of toner. The difference in the movement of the stirring bar 55 is that the Hall element 5
9 is detected. The toner sensor 54 outputs a detection signal corresponding to the remaining amount of toner based on the output of the Hall element 59. The CPU 3 receives the detection signal
It is possible to detect that the hopper 31A is empty.

The electrophotographic printer configured as described above executes a printing process in response to an instruction to print from an external device such as a personal computer, as in the first embodiment described above.

Further, this electrophotographic printer determines the life of the developing device 26A based on the dot count and the drum count, as well as the detection output of the toner sensor 54 and the average consumption of toner, as in the first embodiment. The life of the developing device 26A is determined based on the amount and the number of printed sheets.

FIG. 10 is a flowchart showing the life determining process of the developing device 26A in the electrophotographic printer according to the second embodiment.

First, in step S10, as in the first embodiment, when the number of print dots is counted by the counter 9c, the CPU 3 waits until a predetermined unit of the print processing is completed, and then proceeds to step S11. To determine whether or not the hopper 31A is empty according to the output of the toner sensor. If the hopper 31A is empty, the process proceeds to step S12.
If not, the process proceeds to step S17.

In step S12, the CPU 3 checks whether or not the life count has been set. If it has been set, the process proceeds to step S14, and if not, the process proceeds to the subsequent step S13.

In step S13, the CPU 3 obtains the number of dots until the life (set number of dots), and proceeds to step S17 using the number of dots as the life count.

Even after the toner sensor detects that the hopper 31A is empty, the toner remains in the mechanism 31B below the developing device 26A, so that the remaining amount of toner is necessary for printing. Until the amount becomes less than
Printing can be performed.

If the count value (dot count) of the counter 9c until the toner sensor detects that the hopper 31A is empty is D [dot], and the initial amount of toner in the hopper 31A is T [g]. The average toner consumption per printed dot is T / D [g / dot].
Becomes

If the amount of toner (limit toner amount) from when the toner sensor detects that the toner cartridge is empty to when printing is no longer possible is R [g], the number of dots that can be printed with the remaining toner Is R / (T
/ D) = R × D / T [dot]. For this reason, CP
U3 sets the number of dots as the number of life dots.

The dot count value D is obtained by counting the size and the number of sheets of paper to be printed in accordance with the restriction on the number of digits of the counter 9c, and obtaining the converted value in accordance with the count value and the sheet size. You may. In this case, a value converted as the number of print dots in a case where a predetermined ratio of dots to the total number of dots in the printable area are black for each paper size is also used as the number of print dots.

In step S14, the CPU 3 subtracts the number of print dots (dot count) from the set number of dots, and in subsequent step S15, determines whether or not the life of the developing unit has expired based on the result of the subtraction. Specifically, if the subtraction result is positive, it is determined that the life has not yet arrived, and the process proceeds to step S17. If the subtraction result is 0 or negative, the process proceeds to step S16, and it is determined that the life of the developing device 26A is reached. A display prompting the user to replace the photosensitive drum is displayed on the screen 11, and the life determination process ends.

In step S17, the CPU 3 refers to the count value (drum count) of the counter 8 described above,
It is determined whether or not the number of rotations of the photosensitive drum is equal to or less than a predetermined life count value, and if it is applicable, the process proceeds to step S19. If not, the process proceeds to step S18.
The display unit 11 displays a message urging the user to replace the photosensitive drum on the assumption that the life is 6 A, and ends the life determination process.

When the next predetermined unit of the printing process ends, the execution is started again from step S10.

In step S19, the CPU 3 refers to the count value (the number of prints) of the above-described counter 56 to determine whether or not the number of prints is equal to or less than a predetermined life count value. If so, the developing device 26
The process is terminated assuming that the life of A has not yet arrived, and if the number of prints is greater than the life count value, the process proceeds to step S20.
The display unit 11 determines that the life of the developing device 26A has expired.
Display a message urging the user to replace the photosensitive drum,
The life determination process ends.

The developing device 26A has a life corresponding to the number of prints other than the dot count and the drum count. By determining the life of the developing device 26A according to the number of prints in this manner, the life of the developing device 26A is determined. Can be determined more appropriately.

The number of printed sheets may be counted simply by counting the number of printed sheets irrespective of the type of the sheet, or may be counted by a value weighted by the length and width of the sheet. .

In this electrophotographic printer, the developing device 2 is also operated while the so-called feed for conveying the paper from the paper tray 12 to the photosensitive drum 22 in FIG.
At 6A, the toner is supplied to the photosensitive drum, but during this feed, the recording light is not generated by the LED head 2. Therefore, the toner supplied to the photosensitive drum 22 during the feeding is collected by the mechanism section 31B without adhering to the photosensitive drum 22, and becomes a so-called recycled toner. When printing is repeatedly performed on a sheet having a short sheet length, the ratio of the recycled toner in the toner stored in the mechanism section 31B increases. In addition, short paper is generally considered to have a small width, and recording light from the LED head 2 is not irradiated to a portion where there is no paper. Therefore, when printing is performed on a short paper, a wide paper is used. It is considered that a larger amount of toner is collected by the mechanism unit 31B as recycled toner than when printing is performed on paper. Since the recycled toner is deteriorated due to friction between the developing roller and the toner supply roller, when the ratio of the recycled toner increases, the print quality decreases.

Therefore, as described above, the number of printed sheets correlated with the increase in the ratio of recycled toner is counted, and when the number of printed sheets becomes larger than a predetermined life count value, the life of the developing device 26A is determined. Before the quality is reduced, the life of the developing device 26A can be properly detected.

As described above, in the electrophotographic printer according to the second embodiment, similarly to the first embodiment, the developing device 2 is operated in accordance with the dot count and the drum count.
The life of 6A can be determined.

Even if the hopper 31A becomes empty, the developing device 26A
Since there is toner that has not been consumed in the space in the lower part of the printer, there is some time before printing becomes impossible.

In this electrophotographic printer, as described above, the number of dots (life count value) that can be printed with the remaining toner is calculated from the average amount of toner consumed per dot until the hopper 31A is empty. When the number of printed dots exceeds the life count value, the user is asked to replace the developing device 26A, so that the life of the developing device 26A can be reduced with an appropriate number of printed dots according to the actual use situation. Can be determined. For this reason, a fixed life count value is set, and it is possible to more appropriately instruct the replacement of the developing device 26A as compared with the case where the life is determined by the dot count.

Hereinafter, a specific comparison will be made, for example, in the case where printing at a density of 5% is continuously performed on A4 paper. According to past experimental results, the toner consumption when printing at a density of 5% on A4 paper is 25 mg to 35 mg per sheet. Also, A
Printing at a density of 5% on four sheets corresponds to about 1560000 dots.

Hereinafter, for example, assuming that the toner consumption per A4 sheet is 30 mg, the total toner amount of the developing device is 800
g, the initial amount of toner in the hopper 31A is 500 g, and the printing limit toner amount is 200 g.

In the life judgment based on the dot count, a constant value based on an average toner consumption based on an experimental result or the like is used as a life count value, and the number of printed dots actually printed (dot count) and this life count value are determined. Are compared to determine the life. For example, under the above conditions, 156
Since 30 mg of toner is consumed by 0000 dots, the printing limit toner amount (2
The number of print dots until 600 g of toner is consumed, excluding 00 g), is 15 equivalent to 20,000 A4 sheets.
60000 × 20000 = 3.12 × 10 ¹⁰ dots. Therefore, this 3.12 × 10 ¹⁰ dots is used as the life count value, and when the number of printed dots reaches this life count value, the life of the developing device 26A is displayed.

On the other hand, in the electrophotographic printer of the second embodiment, the consumption of 500 g of toner is detected by the toner sensor 54, and the average consumption of the toner up to that time is obtained. The consumption of the remaining 100 g of toner is detected by counting the number of print dots. Specifically, when the toner consumption is 30 mg per A4 sheet, the count number of consuming 100 g of toner is 100 g ÷ 30 mg = 3334 dots, that is, 1560000 × 3334 = 5.2.
The life count value is set to 0 × 10 ⁹ dots, and when the number of printed dots reaches the life count value, the life of the developing device 26A is displayed.

Incidentally, the actual toner consumption is larger than the assumed consumption, for example, 35 mg per A4 sheet.
In the case where is based on the count of the number of print dots, the life is not displayed until 700 g of toner equivalent to 3.12 × 10 ¹⁰ dots is consumed. Therefore, before the end of the life is displayed, the toner amount in the developing device 26A may fall below the print limit toner amount, and the print result may be blurred. Conversely, when the toner consumption per A4 sheet is smaller than the assumed consumption, for example, 25 mg, the toner consumption is 3.1.
The life is displayed when 500 g of toner for 2 × 10 ¹⁰ dots is consumed. For this reason, although the printing can be performed using the toner of 100 g up to the printing limit toner amount, it is displayed that the life of the developing device 26A is reached.

On the other hand, in the electrophotographic printer according to the second embodiment, when 500 g of toner is consumed, this is detected by the toner sensor, and the average consumption of the toner up to that time is obtained. In order to detect the consumption of the toner, if the actual consumption of the toner for one A4 sheet is 35 mg, the dot count value up to that time is 2.222861 which is a value equivalent to about 14286 sheets.
It becomes 6 × 10 ¹⁰ . Based on the dot count value, the number of dots (life count value) that consume the remaining 100 g of toner is calculated as 2.228616 × 10 ¹⁰ × 100 ÷ 5.
00 = 4.457232 × 10 ⁹ dots, which is equivalent to 2857 A4 sheets. The toner amount corresponding to the life count value is about 100 g, and the number of printing dots that is the printing limit toner amount can be accurately detected.

If the actual toner consumption of one A4 sheet is 25 mg, the dot count value until the toner sensor detects the consumption of 500 g of toner is 20,000 A4 sheets. 3.1 equivalent to
It becomes 2 × 10 ¹⁰ . Based on the dot count value, the number of dots (life count value) that consumes the remaining 100 g of toner is calculated as 3.12 × 10 ¹⁰ × 100 ÷ 500 =
6.24 × 10 ⁹ dots, which is equivalent to 4000 A4 sheets. The amount of toner corresponding to the life count value is about 100 g, and the number of print dots serving as the limit toner amount can be accurately detected.

Therefore, when the life of the developing device 26A is determined by counting the number of print dots, if the actual toner consumption is different from the assumed consumption, the life of the developing device 26A due to the decrease in the toner amount is determined. May not be detected accurately. However, in the electrophotographic printer according to the second embodiment, since the life count value is set according to the actual toner consumption, the printing dot which is the printing limit toner amount is used. The number can be accurately detected, and the life of the developing device 26A due to the decrease in the amount of toner can be more appropriately detected.

Conventionally, in order to detect the remaining amount of toner in the entire developing unit 26A, a stirring bar has to be provided in the mechanism 31B below the developing unit 26A having the developing roller. The mechanism portion 31B also contains the recycled toner as described above. Since the resistance applied to the stirring bar of the recycled toner has changed due to deterioration, the mechanical unit 3
When the stirring bar is provided in the toner container 1B, the stirring bar is easily affected by the deteriorated toner, and it is difficult to improve the accuracy of detecting the remaining amount of the toner. On the other hand, in the present invention, it is sufficient to be able to detect that the remaining amount of the toner is equal to or less than the predetermined amount. Therefore, the stirring bar can be provided in the hopper 31A above the developing device 26A. Therefore, the detection of the remaining amount of toner is less likely to be affected by the deteriorated toner, and the detection accuracy of the remaining amount of toner can be improved. Third embodiment

The electrophotographic printer according to the third embodiment of the present invention has the same configuration as the electrophotographic printer of the first embodiment shown in FIG.

In the electrophotographic printer according to the first embodiment,
Although the life of the developing unit 26 is determined based on the number of rotations of the photosensitive drum (drum count) and the number of print dots (dot count), the electrophotographic printer of the third embodiment further includes By correcting the dot count in accordance with the ratio of black dots (print duty), the life of the developing unit 26 is more appropriately determined.

In printing with a small print duty,
The toner deteriorates as compared with the case where the print duty is large.

A fixed amount of toner is always supplied to the photosensitive drum 22 in the developing unit 26 irrespective of the print duty, and the toner adheres only to the exposed portion of the photosensitive drum 22. Therefore, the print duty is 100%
In this case, the amount of the toner supplied to the photosensitive drum 22 and the amount of the toner transferred to the sheet are balanced, and the toner in the developing unit 26 is transferred to the sheet while the friction of the roller or the like is minimized. Is done.

On the other hand, in printing with a small print duty, the amount of toner attached to the photosensitive drum 22 and transferred to the paper is smaller than the amount of toner supplied to the photosensitive drum 22. The toner that is supplied to the photosensitive drum 22 and does not adhere to the photosensitive drum 22 is
0, rubbed by the photosensitive drum 22 and again
Returned to 6. Even if the damaged toner is returned to the developing unit 26 in this manner, the new toner is supplied to the developing unit 26 during printing as described above, so that the damaged toner is mixed with the new toner. This does not immediately affect print quality.

However, when printing with a small print duty is repeated, the ratio of the damaged toner in the developing unit 26 increases, and while the toner is rubbed and damaged by repetition of the print with a small print duty, The charging performance of the toner deteriorates. This allows
Print quality is degraded by so-called fogging or the like in which toner also adheres to the unexposed portion of the photosensitive drum 22.

For this reason, in the electrophotographic printer of the third embodiment, the above-described dot count is corrected according to the print duty.

More specifically, a correction coefficient corresponding to each print duty is obtained in advance by an experiment or the like, and the correspondence between the print duty and the correction coefficient is stored as a correction table. Make corrections.

FIG. 11 is a flowchart showing the operation of detecting the life of the developing unit 26 with such a correction operation.

First, in step S21, the CPU 3
Waits for the end of a predetermined unit of the printing process, and when the printing process of the predetermined unit is completed, refers to the count value (dot count) of the counter 9c in FIG. Count), and the following step S
In step 22, the print duty is calculated, and in step S2
Proceed to 3.

In step S23, the CPU 3 refers to the correction table stored as described above, reads out the correction coefficient corresponding to the print duty obtained in step S22, and reads the count value of the counter 9c according to the correction coefficient. Is corrected, and the process proceeds to the subsequent step S24.

The correction table includes, for example, as shown in FIG. 12, a print duty and a correction coefficient associated with each print duty. It is assumed that there is almost no damage to the toner in printing with a high printing duty, for example, 60% or more, and the correction coefficient is set to 1. Conversely, when the print duty is low, for example, when the print duty is 40% or less, the damage to the toner is large. Therefore, the correction coefficient is set so as to increase sequentially as the print duty decreases. The CPU 3 calculates the difference between the value obtained by multiplying the correction coefficient obtained from such a correction table by the number of print dots per page obtained in step S21 and the number of print dots per page obtained in step S21. To correct the count value of the counter 9c.

Thus, for example, when the print duty is 60
If the print duty is 40% or less, the number of print dots for one page is corrected according to the corresponding correction coefficient. For example, if the count value of one page having a print duty of 20% is, for example, 312000, 374400 obtained by multiplying the count value by the correction coefficient 1.2 is set to be the count value of one page. The counter value of the counter 9c is corrected.

Note that the numerical values shown in FIG. 12 are set for explanation, and are different from actual values. Further, since the value of the correction coefficient varies depending on the configuration of the electrophotographic printer, the type of toner, and the like, the optimum value is obtained and set through experiments and the like.

After correcting the dot count according to the print duty, the CPU 3 refers to the count value (dot count) of the counter 9c in step S24, and sets the dot counter in advance in step S25. It is determined whether or not the life count value has reached. If the dot count has reached the life count value, it is determined that the life of the developing unit 26 is reached, and the process proceeds to step S2.
Then, if the dot count has not reached the life count value, the process proceeds to step S26.

In step S26, the CPU 3 refers to the count value (drum counter) of the counter 8 and determines in a succeeding step S27 whether or not the drum count has reached a preset life count value. If the drum count has reached the life count value, it is determined that the life of the developing unit 26 has expired, and the process proceeds to step S28. If the drum count has not reached the life count value, the process returns to step S21 to end the next predetermined unit of the printing process. To wait.

In step S28, the CPU 3 displays a message prompting the user to replace the developing unit 26 on the display unit 1.
1 and the process ends.

Thus, the user can see the display on the display section 11 and recognize that the life of the developing unit 26 has expired.

In the electrophotographic printer according to the third embodiment, in addition to the effects of the first embodiment, by correcting the dot count in accordance with the print duty, the developing unit can be considered in consideration of toner deterioration. 26 can be more appropriately detected.

Thus, in consideration of the deterioration of the toner due to the environment, the user can be instructed to replace the developing unit 26 before the deterioration of the print quality becomes remarkable.

In this embodiment, the example in which the CPU 3 corrects the number of print dots per page (dot count) in accordance with the correction coefficient in the above-described step S23 has been described. The number of print dots (dot count) may be counted, and the CPU 3 may accumulate the dot count for each page. In this case, the CPU 3 may correct the dot count for each page based on the correction coefficient and accumulate the corrected values. Fourth embodiment

FIG. 13 is a block diagram showing a configuration of a main part of an electrophotographic printer according to a fourth embodiment of the present invention.

The electrophotographic printer according to the third embodiment corrects the number of print dots (dot count) according to the print duty. However, the electrophotographic printer according to the fourth embodiment further includes an electrophotographic printer. The life of the developing unit 26 is more appropriately determined by correcting the number of printed dots (dot count) in accordance with environmental parameters such as temperature and humidity inside the printer.

Depending on the conditions of temperature and humidity, when a toner image is transferred from the photosensitive drum 22 to a sheet, a transfer failure in which a part of the toner remains on the photosensitive drum 22 may occur. If there is such a transfer failure, the toner remaining on the photosensitive drum 22 is returned to the developing unit 26 again. Since the recycled toner returned to the developing unit 26 is deteriorated due to friction with each roller, the print quality is reduced when the ratio of the recycled toner is increased.

The cause of the transfer failure is mainly a change in the resistance of the transfer roller due to the environment, and the voltage (transfer voltage) between the transfer roller and the photosensitive drum fluctuates due to the change in the resistance. Variations in the transfer voltage can be reduced by controlling the voltage applied to the transfer roller, but this alone is not completely eliminated and a transfer failure occurs depending on the environment.

Therefore, this electrophotographic printer has a temperature sensor 61 for outputting a detection output corresponding to the temperature in the electrophotographic printer, in addition to the configuration of the electrophotographic printer of the first embodiment shown in FIG. And a humidity sensor 62 that outputs a detection output according to the humidity in the electrophotographic printer.

Further, in this electrophotographic printer, similarly to the electrophotographic printer of the third embodiment, a correction coefficient corresponding to the print duty is held as a correction table, and the temperature, humidity, and the like are determined in advance by experiments and the like. For example, a correction coefficient corresponding to each print duty is obtained, and the correspondence between the environment parameters and the correction coefficients is stored as an environment correction table, and the dot count is corrected based on the environment correction table.

FIG. 14 is a flowchart showing the operation of detecting the life of the developing unit 26 with such a correction operation.

First, in step S30, the CPU 3
Waits for the end of a predetermined unit of the printing process, and when the printing process of the predetermined unit is completed, refers to the count value (dot count) of the counter 9c in FIG. Count), and the following step S
In step 31, the print duty is calculated, and in step S3
Proceed to 2.

In step S32, as in the third embodiment, the CPU 3 refers to the correction table, reads out the correction coefficient corresponding to the print duty obtained in step S31, and reads the correction coefficient of the counter 9c according to the correction coefficient. The count value is corrected, and the process proceeds to the subsequent step S33.

In step S33, the CPU 3 reads environmental parameters such as temperature and humidity from the temperature sensor 61 and the humidity sensor 62 in FIG. 13 described above, and in subsequent step S34, the environment stored as described above. Referring to the correction table, the count value of the counter 9c that has been corrected in step S32 is further corrected, and the process proceeds to step S32.
Proceed to 35.

The environment correction table includes, for example, as shown in FIG. 15, temperature and humidity, and correction coefficients associated therewith. This correction factor is determined by the optimal design environment,
For example, it is set so that the value increases as the temperature and humidity deviate from the temperature of 15 ° C. to 25 ° C. and the humidity of 60%.

The numerical values in FIG. 15 are set for explanation, and are different from actual values. Further, since the value of the correction coefficient varies depending on the configuration of the electrophotographic printer, the type of toner, and the like, the optimum value is obtained and set through experiments and the like.

After correcting the dot count in accordance with the environmental parameters, the CPU 3 refers to the count value (dot count) of the counter 9c in step S35, and sets the dot counter in advance in step S36. It is determined whether or not the life count value has reached. If the dot count has reached the life count value, it is determined that the life of the developing unit 26 is reached, and the process proceeds to step S3.
If the dot count has not reached the life count value, the process proceeds to step S37.

In step S37, the CPU 3 refers to the count value (drum counter) of the counter 8 and determines in a succeeding step S38 whether or not the drum count has reached a preset life count value. If the drum count has reached the life count value, it is determined that the life of the developing unit 26 has expired, and the process proceeds to step S39. If the drum count has not reached the life count value, the process returns to step S30 to end the next predetermined unit of the printing process. To wait.

In step S39, the CPU 3 displays a message prompting the user to replace the developing unit 26 on the display unit 1.
1 and the process ends.

Thus, the user can see the display on the display section 11 and recognize that the life of the developing unit 26 has expired.

In the electrophotographic printer according to the fourth embodiment, in addition to the effects of the third embodiment described above, the dot count is corrected in accordance with the environmental parameters, thereby taking into account the deterioration of the toner due to environmental conditions. Developing unit 26
Can be detected more appropriately.

Thus, in consideration of the deterioration of the toner due to the environment, the user can be instructed to replace the developing unit 26 before the deterioration of the print quality becomes remarkable. Fifth embodiment

This electrophotographic printer has the same configuration as the above-described electrophotographic printer of the second embodiment shown in FIG.

In the above-described second embodiment, when the toner sensor detects that the remaining amount of toner has become equal to or less than the predetermined amount, the average consumption amount of toner up to that time is obtained.
Based on this, the printing of the number of dots (life count number) that can be printed with the remaining toner is detected by counting the number of print dots, and the life of the developing device 26A is detected.

On the other hand, in the fifth embodiment, when it is detected by the toner sensor that the remaining amount of toner has become equal to or less than the predetermined amount, the same as in the second embodiment is obtained. The average consumption of toner is calculated.
Unlike the second embodiment, when the consumption amount of the toner is assumed to be a predetermined amount, the number of dots that can be printed with the remaining toner (for example, 100 g similar to the second embodiment described above) is set as the life count value, The subsequent print density is adjusted, the subsequent toner consumption is adjusted, and the life of the developing device 26A is determined based on whether or not the number of print dots is equal to or longer than the life count value.

Since the toner consumption varies depending on the density of the printed image, the toner consumption varies depending on the density of the printed image even if the number of printing dots is the same. Therefore, by adjusting the amount of toner consumption after the toner sensor detects that the remaining amount of toner is equal to or less than the predetermined amount, the detection accuracy of the remaining toner consumption is improved, and the developing device 26A Can be properly determined.

The dot diameter of the electrostatic latent image formed on the photosensitive drum 22 changes depending on the irradiation energy, the irradiation time and the intensity of the recording light. Since the amount of toner adhering to the electrostatic latent image changes according to the dot diameter, the energy of the recording light applied to the surface of the photosensitive drum can be adjusted by adjusting the driving time, the driving output, and the like of the LED head 2. The amount of toner consumption can be adjusted.

In the following, the case where the driving time of the LED head 2 is adjusted will be described. However, the energy of the recording light may be adjusted by adjusting other parameters such as the driving output.

LED used in this electrophotographic printer
As shown in FIG. 16, the head 2 includes a large number of LED elements 63 arranged in a straight line, a driving element 64 for driving the LED elements 63, and a latch for holding print data for driving the driving elements 64. Circuit 65 and printer control unit 1
Shift circuit 66 for sequentially shifting print data from
And control signals (STB1 to STB) from the printer control unit 1.
B4), and an AND gate 67 for controlling the driving by the driving element 64 according to B4).

The LED elements 63 include, for example, four groups (the first group).
To the fourth group), and each group is driven in order to reduce the peak of the current at the time of driving. In order to select a group to be driven, the control signals (STB1 to STB1) supplied via the G / A 6 in FIG.
B4) is used. Control signals STB1, STB2, S
First, second, third and third by TB3 and STB4 respectively
Driving of the fourth group is instructed.

FIG. 17 is a time chart showing the states of the print data DATA and the control signals STB1 to STB4 when such a division drive is performed.

A normal control signal STB1 shown in FIG.
If the timings of STB4 to STB4 are changed as shown in FIG. 7B, the driving time of the LED elements 63 of each group becomes longer, and the density of the electrostatic latent image formed on the photosensitive drum 22 becomes higher. .

FIG. 18 is a flowchart showing a process for equalizing the print density in the electrophotographic printer.

When the toner sensor detects that the toner in the hopper 31A has run out, the CPU 3 acquires the number of print dots at that time from the counter 9 in step S41. The toner consumption per dot is calculated, and the process proceeds to step S43.

Here, the dot count value when the toner sensor detects that the toner has run out is represented by D
Then, since the initial amount of toner in the hopper 31A is a predetermined amount T (g), the average consumption amount of toner per dot so far is T / D [g / dot].
Becomes

In step S43, the CPU 3 converts the average consumption amount obtained in step S42 into a toner amount corresponding to the number of dots when printing on A4 paper at a density of 5%.
Proceeding to 44, the average consumption is compared with the prescribed consumption of 30 mg when printing on A4 paper at a density of 5%. Specifically, a parameter x is obtained by dividing the converted average consumption by a prescribed consumption of 30 mg, and the process proceeds to step S45.

In step S45, an adjustment value corresponding to the parameter x obtained in step S44 is obtained by referring to an adjustment table indicating the adjustment value of the driving time of the LED head 2 obtained in advance through experiments or the like. move on.

This adjustment table is configured, for example, as shown in FIG. 19, and the adjustment value is represented by a ratio from a reference drive time. These adjustment values are
The experiment is set so that the toner consumption per dot is uniform.

In step S46, the CPU 3 adjusts the driving time of the LED head 2 according to the adjustment value obtained in step S45, and ends the print density uniforming process.

As a result, the subsequent print density is adjusted,
The toner consumption is made uniform.

After the toner consumption has been equalized as described above, the CPU 3 determines whether the count value of the counter 9c has become equal to or greater than the above-mentioned life count value for each predetermined unit of the printing process, for example, for one page. Whether the developing unit 26A is replaced is displayed on the display unit 11 when the life count is equal to or longer than the life count, similarly to step S20 and the like in the second embodiment.

In the electrophotographic printer according to the fifth embodiment, when the toner sensor detects that the hopper 31A is empty as described above, the subsequent toner consumption is determined in accordance with the printing status up to that time. By making the amount uniform, the toner consumption can be adjusted to a predetermined value. Even if the life of the developing device 26A is determined according to the remaining life count value obtained as the predetermined toner consumption, the life can be properly adjusted. Can be determined.

In each of the above embodiments, an example in which the present invention is applied to a so-called monochrome electrophotographic printer having one developing unit has been described. However, for example, a color printer using a plurality of developing units or developing units, a facsimile machine, and the like. The present invention can also be applied to apparatuses for color copying and the like.

In each of the embodiments described above, the counter 8 for obtaining the drum count or the counter 9c for obtaining the dot count is described as holding the cumulative value after the developing unit is replaced. The CPU 3 obtains a cumulative value for each page, and stores it in the memory 4 or the like.
The configuration can be changed as appropriate within the scope of the technical idea of the present invention.

[0150]

According to the image recording means of the present invention, when the number of rotations of the photosensitive drum becomes equal to or more than the first threshold value, or when the number of dots becomes second based on the detection output by the second detection means,
When the threshold value is equal to or more than the threshold value, an instruction to replace the developing unit can be displayed. As a result, it is possible to appropriately judge the life of the predetermined developing unit based on the actual situation, based on either the photosensitive drum or the amount of toner consumption correlated with the number of print dots.

Further, in the image recording apparatus according to another aspect of the present invention, when the detecting means detects that the hopper is empty, the toner per dot according to the count value of the counting means. By calculating a life count based on the consumption, and when the count of the counting means thereafter becomes equal to or longer than the life count, a warning signal is used to warn the user. It is possible to more accurately determine the consumption of the toner remaining inside, and to appropriately determine the life of the developing device according to the actual situation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an electrophotographic printer according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a configuration of a printing mechanism that forms the electrophotographic printer.

FIG. 3 is a diagram showing a configuration of a photosensitive drum constituting the electrophotographic printer.

FIG. 4 is a diagram showing a detailed configuration of a dot counter constituting the electrophotographic printer.

FIG. 5 is a time chart showing a printing operation of the electrophotographic printer.

FIG. 6 is a flowchart illustrating a life determining process of a developing unit in the electrophotographic printer.

FIG. 7 is a block diagram illustrating a configuration of an electrophotographic printer according to a second embodiment of the present invention.

FIG. 8 is a side sectional view showing a configuration of a printing mechanism constituting the electrophotographic printer.

FIG. 9 is a side sectional view showing a configuration of a stirring bar constituting the electrophotographic printer.

FIG. 10 is a flowchart showing a life determining process of a developing unit in the electrophotographic printer.

FIG. 11 is a flowchart illustrating a life determining process of a developing unit in an electrophotographic printer according to a third embodiment of the present invention.

FIG. 12 is a diagram illustrating an example of a correction table indicating a relationship between a print duty and a correction coefficient.

FIG. 13 is a block diagram illustrating a configuration of an electrophotographic printer according to a fourth embodiment of the present invention.

FIG. 14 is a flowchart illustrating a life determining process of a developing unit in the electrophotographic printer.

FIG. 15 is a diagram illustrating an example of an environment correction table indicating a relationship between environment parameters and correction coefficients.

FIG. 16 is a diagram showing a configuration of an LED head constituting an electrophotographic printer according to a fourth embodiment of the present invention.

FIG. 17 is a time chart showing a process of adjusting a driving time of a light source by the electrophotographic printer.

FIG. 18 is a flowchart illustrating a life determining process of a developing unit in the electrophotographic printer.

FIG. 19 is a diagram illustrating an example of an adjustment table indicating adjustment values of parameters and driving times of LED heads.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer control part 2 LED head 3 CPU 4 Memory 5 EEPROM 8 Counter 9 Dot counter 11 Display part 22 Photoconductor drum 26 Developing unit 26A Developing device 31A Hopper 31B Mechanical part 54 Toner sensor 61 Temperature sensor 62 Humidity sensor

Continued on front page F term (reference) 2H027 DA13 DA14 DA38 DA44 DD02 EA04 EC20 ED06 ED08 EE02 EE07 EF09 GA41 GB03 HB02 HB13 2H077 AA11 AD06 BA09 DA16 DA18 DB10 DB13 DB14 GA04 9A001 BB04 DD07 HH34 JJ35 KK42 LL09

Claims (8)

[Claims] A photosensitive drum for forming an electrostatic latent image corresponding to a recording light; a storage section for storing toner; and a developing roller for supplying toner stored in the storage section to the photosensitive drum. A replaceable developing unit; first detecting means for detecting the number of rotations of the photosensitive drum; and second counting for counting the number of dots in data for forming an electrostatic latent image on the photosensitive drum. A warning signal when one of the number of rotations of the photosensitive drum detected by the first detection means and the number of dots detected by the second detection means is equal to or greater than a corresponding threshold value; An image recording apparatus comprising: a determination unit that generates a warning; and a warning unit that issues a warning in response to a warning signal from the determination unit. 2. A print parameter detecting means for detecting a parameter indicating a printing condition based on the number of dots detected by the second detecting means, and 2. The image recording apparatus according to claim 1, further comprising a correction unit configured to correct the number of dots counted by the detection unit. 3. The image recording apparatus according to claim 2, wherein the print parameter is a ratio of an electrostatic latent image formed in a unit print area. 4. An environmental parameter detecting means for detecting an environmental parameter in the image recording apparatus, and a correction for correcting the number of dots counted by the second detecting means in accordance with a detection output of the environmental parameter detecting means. 2. The image recording apparatus according to claim 1, further comprising: means. 5. The image recording apparatus according to claim 4, wherein the environmental parameter includes at least one of a temperature and a humidity inside the image recording apparatus. 6. A photosensitive drum for forming an electrostatic latent image according to recording light, a hopper for containing toner, and a developing roller provided below the hopper for supplying toner to the photosensitive drum. A developing unit for developing an electrostatic latent image on the photosensitive drum, the developing unit including a toner supply mechanism having the same, a detecting unit for detecting whether or not the hopper is empty; Counting means for counting the number of dots in the data for forming an electrostatic latent image, and when the counting means detects that the hopper has been emptied, according to the count value of the counting means. Calculating means for calculating the consumption amount of toner per dot and calculating a life count based on the consumption amount; and detecting the empty hopper unit by the counting means. A determination unit that generates a warning signal when the count number of the counting unit is equal to or greater than the life count number calculated by the calculation unit; and a warning unit that issues a warning according to the warning signal from the determination unit. An image recording apparatus, comprising: 7. A photosensitive drum for forming an electrostatic latent image corresponding to recording light, a hopper for containing toner, and a developing roller provided below the hopper for supplying toner to the photosensitive drum. An exchangeable developing device for developing an electrostatic latent image on a photoconductor drum, the detection device detecting whether or not the toner in the hopper is empty, and the photoconductor Counting means for counting the number of dots in data for forming an electrostatic latent image on the drum; and when the detecting means detects that the hopper is empty, the count value of the counting means is A density adjustment unit for adjusting the subsequent print density based on the consumption amount of the toner per dot according to the obtained consumption amount, and after the detection unit detects that the hopper is empty. When the count number of the counting means is equal to or more than a preset threshold, the warning means generates a warning signal, and a warning means which issues a warning according to the warning signal from the determining means. Image recording device. 8. The image recording apparatus according to claim 7, wherein the density adjusting unit adjusts a print density by controlling a drive of a head that irradiates the photosensitive drum with recording light.