JPH09258620A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect that a waste toner bottle is full without providing an exclusive detecting device. SOLUTION: The ON-time M of a toner replenishing motor 25 provided at a toner hopper 24 and the number of copies P detected by an ejected paper sensor 14 are accumulated and stored in a RAM. The CPU 22 calculates the quantity of waste toner by using the time M and the number P, and moreover, following coefficients are experimentally decided. A: toner quantity replenished to a developing device 4 Per unit-hour. B: the toner quantity consumed at one toner patch forming. T: the ratio of a toner image corresponding to an original image being transferred on paper(transfer efficiency). When the quantity of the waste toner calculated reaches the allowable quantity of the waste toner bottle previously set, a message requesting the exchange of the waste toner bottle 21 is displayed on a display panel.

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 such as an electrophotographic copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art Generally, in image forming apparatuses such as electrophotographic copying machines, printers, and facsimiles, toner is used to form an image, and the toner remaining on the image carrier after the image formation has been used. The waste toner is collected in a waste toner bottle.

Conventionally, various techniques for detecting the fullness of the waste toner bottle have been proposed, but a direct detection method such as measuring the weight of the waste toner bottle requires a dedicated detection device. A method of indirectly detecting the fullness of the waste toner bottle is preferable. As a method of indirectly detecting the fullness of the waste toner bottle, for example, Japanese Patent Publication No. 4-61351 discloses a technique of integrating the toner supply time and detecting the fullness of the waste toner bottle from the integrated value. It is disclosed.

[0004]

However, in the conventional technique described in the above publication, the amount of waste toner actually generated and the amount of waste toner calculated by integrating the toner replenishment time are calculated. There was a problem that there was a gap between them.

That is, in the conventional image forming apparatus as described in the above publication, for example, in order to maintain a stable image density, a toner patch of toner is formed on the image carrier, and the density of the toner patch is increased. When an automatic image density control mechanism is provided that automatically adjusts the image forming density based on the measured value, the toner amount consumed for forming this toner patch is not taken into consideration. There is a gap between the amount of waste toner generated in the above process and the amount of waste toner calculated by integrating the toner replenishment time.

As a toner patch formed between a plurality of toner images corresponding to the original image, an electrophotographic apparatus using a laser diode as an exposure source is used in addition to the above-mentioned one for detecting the image density. There are toner patterns formed as a result of light emission for automatic output adjustment of the laser diode, various toner patches formed for stabilizing the electrophotographic process and reducing image noise. Since such toner patches are not transferred to the recording medium and are all collected as waste toner, the amount of waste toner between the amount of waste toner actually generated and the amount of waste toner calculated by integrating the toner replenishment time is calculated. The effect on the gap is great.

An object of the present invention is to provide an image forming apparatus which solves the above problems and is capable of accurately detecting the amount of used toner with a simple structure.

[0008]

In order to achieve the above object, an image forming apparatus of the present invention comprises an image carrier and a toner image forming means for forming a toner image corresponding to a document image on the image carrier. A toner replenishing means for replenishing the toner image forming means with toner; a toner patch forming means for forming a toner patch on the image carrier; And a calculation means for calculating the amount of used toner based on the above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a digital electrophotographic copying machine 100 which is an embodiment of the present invention. As shown in FIG. 1, a photoconductor drum 1 is provided in the center of the main body of the copying machine 100, and a charging charger 2, a laser scanner 3, a developing device 4, a transfer charger 5, and an optical reflection sensor are provided around the photoconductor drum 1. Image density sensor 6, which is
The cleaner 7 and the eraser lamp 8 are sequentially arranged. A platen cover 1 is provided on the top of the main body of the copying machine 100.
7, an original platen glass 18, and an image reader 16 for reading an image of an original document placed on the original platen glass 18. Below the image reader,
Fixing roller 12, paper ejection sensor 1 for detecting paper ejection
4 and a paper discharge roller 13, and a paper discharge port 31 and a paper discharge tray 15 are provided on the sides thereof. Further, a paper cassette 9 for accommodating paper as a recording medium is provided at the lower part of the main body of the copying machine 100, and the copying machine 100 is directed upward from the front end of the paper cassette 9.
A sheet conveying path 19 is provided so as to cut the inside of the sheet substantially vertically. The reference numeral 30 denotes a drive motor for driving the image forming unit including the photosensitive drum 1 and process equipment provided around the photosensitive drum 1.

The image forming operation of the copying machine 100 will be briefly described. First, the image reader 16 reads an image of an original document stacked on the original platen glass 18. On the other hand, the photosensitive drum 1 starts to rotate in the direction of arrow a, and the surface of the photosensitive drum 1 is uniformly charged by the charging charger 2,
The laser scanner 3 emits light based on the original image data read by the image reader 16 to form an electrostatic latent image on the photosensitive drum 1. Then, the developing device 4 develops the electrostatic latent image with the toner, and a toner image corresponding to the original image is formed on the photosensitive drum 1.

On the other hand, when the paper feed roller 10 provided near the paper cassette 9 rotates, the paper is supplied from the paper cassette 9 into the main body of the copying machine. The sheet of paper reaches the timing roller 11 provided in the vicinity of the photoconductor drum 1 through the sheet conveyance path 19 and is temporarily stopped. Then, by the rotation of the timing roller 11, the paper is fed toward the facing portion of the photoconductor drum 1 and the transfer charger 5 in synchronization with the toner image on the photoconductor drum 1, and the toner image on the photoconductor drum 1 is fed. Is transferred to the paper.

The sheet on which the toner image has been transferred is sent to the fixing roller 12, where the toner image on the sheet is fixed, then passes through the sheet discharge sensor 14, and is discharged to the sheet discharge tray 15 by the sheet discharge roller 13. . The paper discharge sensor 14 is
As will be described later, it is used to detect the presence or absence of a paper jam in the copying machine by checking whether or not the paper is discharged within a predetermined time.

FIG. 2 is a schematic diagram for explaining a structure for supplying the toner to the developing device 4 and a structure for collecting the toner on the photosensitive drum 1. As shown in FIG. 2, a toner inlet 4a for taking in unused toner is provided at one end of the developing device 4. Above the toner intake port 4a, a toner hopper 24 containing unused toner therein is provided.
Is provided. The toner hopper 24 is provided with a toner storage chamber 27, a toner replenishment motor 25, a screw 26 connected to the motor 25, and a toner supply port 24a. The toner replenishment motor 25 operates to rotate the screw 26. The toner in the toner storage chamber 27 is pushed out, and the toner is supplied from the toner supply port 24a to the toner intake port 4a of the developing device 4.

On the other hand, one end of the cleaner 7 is provided with a toner discharge pipe 7a for discharging the residual toner collected from the photosensitive drum 1 to the outside of the cleaner 7. The toner discharge pipe 7a is inserted into the waste toner pipe 20 connected to the waste toner bottle 21, and the toner on the photoconductor drum 1 scraped off by the cleaner 7 is finally used as the waste toner. Will be recovered in.

Further, as shown in FIG. 2, the image density sensor 6, the paper discharge sensor 14, and the toner replenishment motor 25 are connected to a central processing unit (CPU) 22, which is driven and controlled by the CPU 22 and outputs thereof. It is detected by the CPU 22. The paper discharge sensor 14, the toner replenishment motor 25, and the CPU 22 constitute a mechanism that indirectly detects the toner replenishment amount and the waste toner generation amount, as described later. The CPU 22 has an operation panel 2 which will be described later.
3 are connected.

The image density sensor 6 detects the density of the toner patch formed on the photosensitive drum 1 and outputs it to the CPU 22. The CPU 22 rotates the toner replenishment motor 25 for a predetermined time according to the output of the image density sensor 6 to replenish the toner to the developing device 4, and adjusts the image formation so that the image is formed at a constant density.

Further, the paper discharge sensor 14 is a paper discharge roller 13
CPU 22 detects the passage of the trailing edge of the paper sent toward
Output to The CPU detects from the output from the paper discharge sensor 14 that one image has been formed.

FIG. 3 is a schematic view showing how toner patches are formed on the photosensitive drum 1. After one image 50 corresponding to the original image is formed, the CPU 22 drives and controls the laser scanner 3 to perform exposure, and this is developed by the developing device 4, and as shown in FIG. A toner patch is formed in the central portion of. As shown in FIG. 3, in the present embodiment, the toner patch 60 is formed every time the formation of one toner image 50 corresponding to the original image is completed. The image density sensor 6 shown in FIGS. 1 and 2 is provided so as to face the position where the toner patch 60 is formed. Reference numeral 70 indicates a slit-shaped toner pattern formed by the laser scanner 3 emitting light for one line between images in order to automatically adjust the output of the laser scanner 3. The toner patch thus formed on the photosensitive drum 1 is
Like the residual toner generated by the toner image formation corresponding to the original image, it is scraped off by the cleaner 7 and finally collected in the waste toner bottle 21.

FIG. 4 is a schematic view of the operation panel 23 provided on the upper surface of the copying machine 100. As shown in FIG. 4, a display panel 231 for displaying various messages and a copy key 23 for instructing copying are provided on the operation panel 23.
2 and a numeric keypad 23 for entering numerical values such as the number of copies
3, a density adjustment key 234, a magnification adjustment key 235,
A paper size selection key 236, a clear key 237 for clearing the input numerical value, a stop key 238 for stopping the copying operation, and a reset key 239 for initializing the set copying conditions are provided.

FIG. 5 shows a display example performed by the display panel 231. FIG. 5A is an example of a display in the standby state, which displays the copy density, the copy magnification, the paper size, and the current copy ready state. FIG. 5 (b)
Shows an example of a display when the waste toner bottle is full. In addition to notifying that the waste toner bottle is full, a message prompting to replace the waste toner bottle with a new one is displayed. FIG. 5C is a display example when a paper jam has occurred. In addition to notifying that a paper jam has occurred, a message prompting the user to remove the jammed paper is displayed. Note that in FIGS. 5B and 5C, the fact that the waste toner is full and the paper jam has occurred is notified, and the display of the copy condition as shown in FIG. It informs the operator that it is in a prohibited state.

FIG. 6 is a control circuit diagram of the copying machine 100. As shown in FIG. 6, this electronic circuit includes a CPU 22.
The RAM 40, the image density sensor 6, the paper discharge sensor 14,
An operation panel 23 including a display panel 231 and a copy key 232, an image reader 16, a laser scanner 3, a toner replenishing motor 25, a drive motor 30 for driving an image forming unit, and other input / outputs connected. Is.

The CPU 22 controls the O of the toner replenishment motor 25.
N time is measured and accumulated in the RAM 40, and the number of copies detected by the paper discharge sensor 14 is also stored in the RAM 40.
40 for cumulative storage. Here, the former value is M and the latter value is P.

The CPU 22 calculates the amount of consumed toner by using the values of M and P described above and the following coefficient determined experimentally in advance.

A: Amount of toner replenished to the developing device 4 by the rotation of the toner replenishment motor 25 per unit time B: Amount of toner consumed to form one toner patch T: Formed on the image carrier Ratio of Transfer of Toner Image Corresponding to Original Image on Paper (Transfer Efficiency) Hereinafter, a specific method of calculating the waste toner generation amount will be described.

The cumulative amount of toner supplied from the toner hopper 24 to the developing device 4 is represented by "A * M". Of the toner replenished to the developing device 3, the cumulative amount of toner consumed for forming a toner patch is represented by “B × P”. Therefore, the cumulative amount of toner consumed for image formation for copying an original is “A × M × B × P”. The toner image formed corresponding to the original image is transferred onto the sheet with transfer efficiency T. That is, since the ratio of waste toner is "1-T", the cumulative amount of waste toner generated by copying an original document is "(A * MB * P) * (1-T)". Therefore, the cumulative value of the total amount of waste toner is the cumulative amount of toner used in the above-mentioned toner patch “B ×
"{(A * M * B * P) * (1-T)} + which added" P "
(B × P) ”.

Since the above-mentioned coefficients may change depending on the environmental conditions and the like, in the present embodiment, the keys on the operation panel 23 can be used to change them appropriately. Specifically, by simultaneously pressing two specific keys of the numeric keypad 233, the maintenance mode as shown in FIG. 7 is entered, and in this mode the numeric keypad 233 is entered.
The coefficients A, B and T can be changed by operating. For the same reason, the allowable amount of waste toner may be changeable.

The CPU 22 calculates the amount of waste toner (hereinafter referred to as “Y”) by a margin amount, which is determined in advance in consideration of fluctuations in transfer efficiency due to environmental conditions, variations in toner replenishment amount, and the like. When the waste toner allowable amount (hereinafter, referred to as K) determined in consideration of handling property when replacing the bottle 21 is reached, the waste toner bottle 21
Is determined to be full and the display panel 2 of the operation panel 23
A message is displayed on 31 to prompt replacement of the waste toner bottle 21.

FIG. 8 is a flow chart showing the flow of a series of copying processes performed by the CPU 22. As shown in FIG.
After setting the copy conditions, the operator sets the copy key 232 to O
When the copy is started with N, and the copying is started, it is first confirmed whether or not the paper is currently jammed (step S100). If the paper jam has occurred, the printing operation is not performed and the process is terminated. If the paper jam has not occurred, the process proceeds to step S104.

In step S104, the value Y representing the amount of waste toner generated is compared with the value K representing the amount of toner corresponding to the toner storage allowable amount of the waste toner bottle. If Y is not smaller than K, it is determined that the waste toner bottle 21 is full, and the display panel 231 displays that the waste toner bottle is full. If the display of the full waste toner bottle has already been displayed, the process is terminated as it is (steps S132 and S134). In step S104, Y
If is smaller than K, it is determined that the waste toner bottle 21 is not yet full, and the process proceeds to step S106.

In steps S106 to S112, reading the original image by the image reader 16, turning on the drive motor 30, adjusting the output of the laser scanner 3, forming a toner image based on the original image, and transferring / fixing the image onto a sheet. The following series of copying operations are performed. In the following step S114, an image density detecting toner patch is formed on the photosensitive drum 1.

Next, in step S116, it is determined whether the paper discharge sensor 14 has detected the trailing edge of the paper within a predetermined time. If not detected, it is determined that a paper jam has occurred, and the display panel 231 is determined in step S130.
A message indicating that a paper jam has occurred is displayed above, and the process ends. When detected, the variable P stored in the RAM 40 is incremented in step S118, and the process proceeds to step S120. In this way, the number of toner patch formations is accumulated and counted in the variable P stored in the RAM 40.

In step S120, the output of the image density detection sensor 6 is compared with a predetermined value. If the output of the image density detection sensor 6 is smaller than a predetermined reference value,
It is determined that the image density is not sufficient, and in step S122, the operating time of the toner replenishing motor 25 this time is added to the variable M stored in the RAM 40, and the step S126 is performed.
Proceed to. When the output of the image density detection sensor 6 is not smaller than the reference value in step S120, it is determined that the image density is sufficient, and the process proceeds to step S126.

In step S126, it is determined whether or not all the set copying operations have been completed. If all the copying operations have been completed, then in step S128 the image forming unit drive motor is turned off, and the processing ends. If all have not been completed, the process returns to step S104 and continues.

When the paper causing the paper jam is removed, or when the waste toner bottle 21 is replaced with a new one, the CPU 22 displays the display on the display panel 231 in FIG. 5 (a). The display is returned to the display indicating the standby state as described above, and the copy prohibition state is released and control is performed to switch to the copy enable state.

As described above, in this embodiment, the cumulative time when the toner replenishment motor 25 is operated and the paper discharge sensor 14 are
Since the amount of waste toner is calculated based on the cumulative value of the number of copies detected by, it is possible to accurately detect the amount of waste toner generated. For example, the operating environment of the image forming apparatus by the operator, that is, Even if the image density is different, the image area is different, and the like, there is no fear that the difference between the calculated amount of waste toner and the actually generated amount of waste toner becomes large. Further, since the amount of waste toner generated can be accurately detected, it is not necessary to set the toner storage allowable amount of the waste toner bottle to be small, and the frequency of replacement of the waste toner bottle can be reduced.

In the present embodiment, when the waste toner storage capacity of the waste toner bottle is reached, the full display of the waste toner bottle and the prohibition of copying are performed. Before the capacity is reached, a warning that the waste toner bottle is almost full may be issued without prohibiting copying.

[0037]

As described above, in the present invention, the used toner amount is calculated based on the cumulative time required for toner replenishment and the cumulative number of times the toner patch is formed, which is simple. With the configuration, the amount of used toner can be accurately detected.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a digital electrophotographic copying machine.

FIG. 2 is a schematic diagram showing a configuration for supplying toner to a developing device and a configuration for collecting toner on a photosensitive drum.

FIG. 3 is a diagram showing how a toner patch for image density detection and a toner pattern formed by laser scanner automatic output adjustment are formed on a photosensitive drum.

FIG. 4 is a schematic view of an operation panel.

FIG. 5 is a diagram showing a display example of a display panel.

FIG. 6 is a block diagram of a control circuit of the copying machine.

FIG. 7 is a diagram showing a display example of a display panel when a coefficient used for calculating a waste toner generation amount is changed.

FIG. 8 is a flowchart showing a flow of copy processing performed by a CPU.

[Explanation of symbols]

 1 Photosensitive Drum 2 Charging Charger 3 Laser Scanner 4 Developing Device 5 Transfer Charger 6 Image Density Sensor 7 Cleaner 9 Paper Cassette 10 Paper Feed Roller 12 Fixing Roller 13 Paper Ejection Roller 14 Paper Ejection Sensor 20 Waste Toner Pipe 21 Waste Toner Bottle 22 Center Processor (CPU) 23 Operation panel 24 Toner hopper 25 Toner supply motor 30 Image forming drive motor 50 Toner image area corresponding to original image 60 Toner patch for image density detection 70 Toner pattern by laser scanner output adjustment 231 Display panel 232 Copy key 233 numeric keypad

Claims (8)

[Claims] 1. An image carrier, and a toner image forming means for forming a toner image corresponding to an original image on the image carrier,
Toner replenishing means for replenishing toner to the toner image forming means, toner patch forming means for forming a toner patch on the image carrier, cumulative time required for toner replenishment, and cumulative number of times toner patches have been formed. An image forming apparatus comprising: a calculating unit that calculates a used toner amount based on the image forming apparatus. 2. A toner collecting means for collecting the toner on the image carrier and storing it in a container having a predetermined capacity, and a value calculated by the calculating means reaches an allowable amount of the toner contained in the container. The image forming apparatus according to claim 1, further comprising an informing unit for informing this. 3. The image forming apparatus according to claim 2, wherein image formation by the toner image forming unit is prohibited when the calculated value of the calculating unit reaches a permissible amount of toner contained in the container. 4. The image forming apparatus according to claim 1, further comprising image density measuring means for measuring an image density of the toner patch. 5. The image forming apparatus according to claim 4, wherein the toner replenishing means performs the replenishing operation based on the measurement value of the image density measuring means. 6. The image forming apparatus according to claim 1, wherein the toner patch is formed every predetermined number of times of image formation, and the calculating unit detects the number of toner patch formations by counting the number of image formations. 7. A transfer unit for transferring a toner image corresponding to an original image formed on the image carrier to a recording medium, wherein the calculating unit is further replenished by the toner replenishing unit per unit time. The image forming method according to claim 1, wherein the used toner amount is calculated based on a toner amount, a toner amount consumed for forming one toner patch, and a ratio of a toner image corresponding to an original image to a recording medium. apparatus. 8. The amount of toner replenished by a toner replenishing unit per unit time, the amount of toner consumed to form one toner patch, and the ratio of a toner image corresponding to an original image transferred to a recording medium. The image forming apparatus according to claim 7, further comprising a changing unit that changes at least one.