JP2003186296A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can accurately detect the amount of a developer and always transmit the accurate developer amount to a user without being influenced by variation of a humidity distribution due to moisture absorption of toner and environmental changes such as variation of a temperature distribution due to ambient temperature variation. <P>SOLUTION: The image forming apparatus is equipped with: an image carrier 1; a cartridge 20 which is freely attachable to and detachable from an image forming apparatus main body and has a developing device 4 having developer storage parts 41 and 42 containing a developer T for forming a toner image by developing an electrostatic latent image on the image carrier 1; and developer remaining amount detecting means 43 and 47 which detect the remaining amounts of developers in the developer storage parts 43 and 47, and the apparatus forms an image on a recording medium. The image forming apparatus further has an environment detecting means which detects the installation environment of the cartridge 20 in the image forming apparatus main body and corrects detected values as developer remaining amount detection results obtained by the developer remaining amount detecting means 43 and 47 according to the detection result of the environment detecting means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electrophotographic image forming apparatus, and more particularly to a cartridge, that is, a process cartridge, or a cartridge developing device (also referred to as a developing cartridge) for electrophotographic image forming. The present invention relates to an electrophotographic image forming apparatus that is attachable to a main body of an apparatus and includes a developer remaining amount detecting unit that detects a remaining amount of developer.

Here, as an electrophotographic image forming apparatus,
For example, an electrophotographic copying machine, an electrophotographic printer (for example,
LED printers, laser beam printers, etc.), electrophotographic facsimile machines, electrophotographic word processors, etc.

A cartridge which can be attached to and detached from the main body of the electrophotographic image forming apparatus includes an electrophotographic photosensitive member as an image carrier, a charging means for charging the electrophotographic photosensitive member, a developing means for supplying a developer to the electrophotographic photosensitive member, It means one having at least one of cleaning means for cleaning the electrophotographic photosensitive member.

Particularly, the process cartridge is a cartridge in which at least one of the charging means, the developing means and the cleaning means and the electrophotographic photosensitive member are integrally formed into a cartridge.
This cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. Alternatively, at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus.

[0005]

2. Description of the Related Art An electrophotographic image forming apparatus such as a copying machine or a laser beam printer emits light corresponding to image information as an image bearing member for an electrophotographic photosensitive member (hereinafter referred to as "photosensitive member").
To form an electrostatic latent image, and a developing means supplies a developer as a recording material to the electrostatic latent image to visualize it as an image. Further, the image is formed on the recording material as a recording medium from the photoconductor. An image is formed on the recording material by transferring.

To the developing means provided in the developing device, a toner container as a developer accommodating portion for accommodating toner as a developer is connected, and the toner is consumed by forming an image. The developer accommodating portion as the developing device, the developing means, the photoconductor, the charging means, and the like are individually configured as cartridges so as to be attachable to and detachable from the image forming apparatus, or the photoconductor is integrally configured with other components. When the toner runs out, the user can replace the cartridge developing device (developing cartridge) or the process cartridge equipped with the developing device to display an image again. Can be formed.

In order to ascertain at any time how much toner remains for image formation in the developer collecting portion of the process cartridge or the developing cartridge (hereinafter collectively referred to as "cartridge"), the toner has recently been used. An increasing number of devices have a toner remaining amount level detecting means, which is a developer remaining amount detecting means capable of detecting the remaining amount level, in a process cartridge or an electrophotographic image forming apparatus main body.

[0008] As a means for carrying out this toner residual amount level detection, a detection method by a change in electrostatic capacity using a condenser-type bipolar sheet metal, or by allowing light to enter the toner container,
There is a detection method by measuring the difference between the transmitted light amount and the received light amount.

As an example, a detection method based on a change in electrostatic capacitance between bipolar metal plates will be introduced. In this system, at least one or more planar conductive sheet metal (hereinafter referred to as "plate sheet metal") that faces a developer carrier, which is a developing means, such as a developing roller, is provided, and the developing roller and the plate sheet metal are condensers. It is used as an electrode of the above, and the fact that the capacitance between the electrodes changes according to the amount of the insulating toner is used.

Further, when the toner amount is measured or the detection accuracy is improved at a place distant from the developing roller, the plate sheet metal is installed at a position where the detection accuracy is desired to be increased to increase the total area or the developing roller. By installing the plate sheet metal to which the bias is applied as described above, it is possible to detect the remaining toner amount with the same or higher accuracy.

That is, if the space between the condensers composed of the plate metal plate and the developing roller is filled with toner, the electrostatic capacity increases, and as the toner decreases, air increases in the space and the electrostatic capacity decreases. To go.

Therefore, it is possible to detect the toner remaining amount level in the toner container by preparing a table in which the relationship between the electrostatic capacity between the plate metal plate and the developing roller and the toner amount is related in advance, that is, a threshold table. I am trying.

Further, regardless of the developing roller and the plate sheet metal, it is possible to detect the toner residual amount level with two sheet metals capable of forming a condenser or a condenser constituted by a plurality of sheet metals.

Further, when these toner remaining amount level detecting means are provided in the developing device in the cartridge, in order to detect the toner remaining amount level with higher accuracy, readable / writable storage means for each cartridge ( There is also a method of providing a memory) and storing the following 1 and 2 for each cartridge.

1: Toner remaining amount value information (for example, remaining amount 25)
%, Information such as remaining amount of 10%) 2: History information indicating that the toner amount is less than or equal to a predetermined value (for example, "tone" means that a new cartridge should be prepared shortly before the toner runs out.
"r-Low" signal, information indicating whether or not a "Toner-Out" signal was issued, which means that a new cartridge should be prepared immediately before the toner runs out)

Above, 1: "remaining toner amount value information", 2:
The advantage of storing "history information indicating that the toner amount is equal to or less than the predetermined value" in the storage means will be described.

Generally, the toner state in the cartridge is often not stable immediately after the start of use of the cartridge or immediately after the cartridge is taken in and out. The toner state is not stable with respect to the usage state of. Even if the detection is performed using the electrostatic capacitance value between the capacitors formed by the plate sheet metal and the developing roller at that time, the detection accuracy may be low.

Therefore, when it is considered that the cartridge has been used or that the cartridge has been taken in and out, the display is often not performed until a predetermined time elapses immediately after the cartridge is used. Alternatively, even if it is performed, the detection accuracy is often low.

However, as described above, the storage means is mounted on each cartridge, and "toner remaining amount value information" and "history information indicating that the toner amount is less than or equal to a predetermined value" are stored, so that the developing process is performed. Even when the remaining amount detection accuracy seems to be low, by using the value stored in the storage means immediately before that, more accurate "toner remaining amount value information" and "toner amount The history information indicating that the value is equal to or less than the predetermined value can be instantly shown to the user.

Further, since each cartridge has the storage means, the same effect can be obtained even when the main body of the image forming apparatus is changed.

Conventionally, the remaining amount of toner can be detected with higher accuracy by these techniques and sequences.

Furthermore, when a problem such as a contact failure of an electrical contact connecting the image forming apparatus main body and the cartridge main body occurs when the cartridge is attached or detached, and when the storage means is not mounted, detection is made by the contact failure. There is a case in which the detected value of the remaining toner amount is determined to be a true value. Even in that case, by providing the storage means, the detected values of the remaining toner amount before and after the cartridge is attached / removed are compared with each other, and the detected value has a change width larger than possible, or during the paper passing operation. When the detected value of the remaining toner amount fluctuates greatly, it is possible to take measures such as notifying the user of the fact.

[0023]

However, in the toner remaining amount detecting method for detecting the change in the electrostatic capacity of the toner interposed between the bipolar sheet metals as shown in the above-mentioned conventional example, there are the following problems. Occurs.

In the conventional toner remaining amount detecting method, the relationship between the remaining amount of toner and the electrostatic capacitance between the plate sheet metal and the developing roller is related to the change in the electrostatic capacitance of the toner interposed between the bipolar sheet metals. The remaining toner amount is calculated from a table in which the above is associated, that is, a threshold value table, and the calculation result is notified to the user.

At this time, when a minute powder such as toner is used, water is contained between the powders, and the electrostatic capacity of the toner is greatly changed.

Then, there is a possibility that the change in the electrostatic capacity due to the moisture absorption is detected as a change in the toner amount, and as a result, an incorrect remaining toner amount is presented to the user.

Further, the fluidity of the toner may change depending on the temperature distribution of the toner itself. That is, as the fluidity of the toner changes, the behavior of the toner between the bipolar sheet metals changes, and the capacitance itself may not be a desired value, and incorrect information may be provided to the user. There is.

Therefore, in order to distinguish a change in capacitance due to environment such as moisture absorption or temperature distribution from a change in regular capacitance, when a rapid change in capacitance is observed, the detected electrostatic capacitance is detected. We have taken countermeasures such as prohibiting the calculation of the residual toner from the capacity.

However, the prohibition of the remaining amount calculation due to such a rapid change of the electrostatic capacitance is avoided even if the abnormality detection is avoided.
While the anomaly detection is being observed, there arises a problem that accurate information cannot be transmitted to the user.

Therefore, the object of the present invention is to accurately detect the developer amount without being affected by environmental changes such as changes in humidity distribution due to moisture absorption of toner and changes in temperature distribution due to changes in ambient temperature. An object of the present invention is to provide an image forming apparatus capable of always transmitting an accurate developer amount to a user.

[0031]

The above object can be achieved by an image forming apparatus according to the present invention. In summary, the present invention is
A cartridge detachably mountable to the main body of the image forming apparatus, which includes a developing device having an image carrier and a developer accommodating portion for accommodating a developer for developing an electrostatic latent image on the image carrier to form a toner image. In the image forming apparatus for forming an image on a recording medium, the installation environment of the cartridge inside the main body of the image forming apparatus, comprising: An environment detecting unit for detecting the above, and correcting the detection value of the developer remaining amount detection result obtained by the developer remaining amount detecting unit according to the detection result of the environment detecting unit. An image forming apparatus is provided.

According to one embodiment of the present invention, the developer remaining amount detection result is detected by using a threshold value table, and the threshold value of the threshold value table is corrected according to the detection result of the environment detecting means. By doing so, it is possible to correct the detection value of the developer remaining amount detection result.

According to another embodiment of the present invention, a toner is formed on the image carrier by further forming a nip facing the image carrier, holding the recording medium in the nip. The environment detection unit has a transfer member that transfers an image onto the recording medium, and detects the installation environment by using a resistance value of the transfer member.

According to another embodiment of the present invention, it further comprises a fixing device which is heated until a predetermined target fixing temperature is reached, and fixes the image formed on the recording medium, and the environment detecting means. The installation environment is detected by using the arrival time until the fixing device is heated to the target fixing temperature.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION An image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. The present invention is particularly applicable to electrophotographic image forming apparatuses such as copying apparatuses, image recording apparatuses, printers, and facsimiles, and the dimensions, materials, and shapes of the components described in the following embodiments are The relative arrangement and the like do not limit the scope of the present invention to them unless otherwise specified.

Embodiment 1 FIG. 1 is a schematic sectional view of an image forming apparatus to which the present invention is applied. In FIG. 1, the photosensitive drum 1 as an image carrier is
A photosensitive material such as C or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel, and is rotated by a driving means A in a clockwise direction indicated by an arrow at a predetermined peripheral speed.

Around the rotating photosensitive drum 1, a charging means for uniformly charging the surface of the photosensitive drum 1 to a predetermined polarity and potential is provided. In this example, a contact charging device 2 using a charging roller is provided. I am using.

A laser beam scanner 3 is used in the present example as the image information exposing means constituting the latent image forming means. The laser scanner 3 is composed of a semiconductor laser, a polygon mirror, an Fθ lens, etc., and is turned on according to image information sent from a host device (not shown).
A laser beam L controlled to be turned on / off is emitted to scan and expose the surface of the photosensitive drum 1 uniformly charged by the charging device 2 to form an electrostatic latent image.

The developing device 4 constituting the cartridge develops the electrostatic latent image on the photosensitive drum 1 as a toner image. As a developing method, a jumping developing method, a two-component developing method, or the like is used, and it is often used in combination with image exposure and reversal developing.

A transfer roller 5 which is a rotating member-shaped contact charging member having an elastic layer provided as a transfer member.
Is brought into pressure contact with the photosensitive drum 1 to form a transfer nip portion N, and the driving unit B rotationally drives the photosensitive drum 1 in a forward direction b, which is an arrow direction, at a predetermined peripheral speed. .

The toner image formed on the rotating photosensitive drum 1 is recorded on the recording material P (transferred material) which is the recording medium fed from the paper feeding portions 7 and 14 to the transfer nip portion N. And sequentially electrostatically transferred.

The recording material P fed from the paper feeding portion such as the manual paper feeding portion 7 and the cassette paper feeding portion 14 is waited by the pre-feed sensor 10, and then the registration roller 11, the registration sensor 12 and the pre-transfer guide 13 are provided. Pass through the transfer nip portion N
The paper is fed to the (image forming unit). The recording material P is taken out by the registration sensor 12 in synchronism with the toner image formed on the surface of the photosensitive drum 1, and the photosensitive drum 1 and the transfer roller 5 are ejected.
And is supplied to the transfer nip portion N formed by. Further, in order to avoid the problem of double feeding in which a plurality of recording materials are mistakenly fed at the time of feeding the recording material P in the paper feeding units 7 and 14, separation rollers 8 and 15 are provided. There is.

The recording material P which has received the transfer of the toner image at the transfer nip portion N and has passed through the transfer nip portion N is separated from the surface of the photosensitive drum 1 and passes through the sheet path 9 to a fixing device 18 which is a fixing means. Be transported.

The fixing device 18 of this embodiment is a film heating type fixing device constituted by a heating film unit 18a and a pressing roller pair of a pressure roller 18b, and the recording material P holding the toner image is the heating film unit 18a. The toner image is nipped and conveyed at the fixing nip portion N ′, which is the pressure contact portion of the pressure roller 18b, and is heated and pressed to form a toner image on the recording material P.
It is fixed on top and becomes a permanent image. The recording material P having the toner image fixed thereon is face-up 1 according to the discharge roller 19.
6 or discharged to face down 17.

On the other hand, the surface of the photosensitive drum 1 after the transfer of the toner image onto the recording material P is cleaned by the removal of the transfer residual toner by the cleaning device 6 constituting the cartridge, and is repeatedly used for image formation again. To be done. The cleaning device 6 of this example is a blade cleaning device, and includes a cleaning blade 61.

In the present invention, at least the developing device 4 is detachably attached to the image forming apparatus as a cartridge having a developing means and a developer accommodating portion.
Further, as described in the conventional example, in the electrophotographic image forming apparatus, the photosensitive drum 1, which is an electrophotographic photosensitive member that constitutes an image bearing member related to image formation, is integrated with surrounding members to form a process cartridge. In many cases, at least the developing device 4 is integrated with the photosensitive drum 1 in the present invention. In the process cartridge 20 of this embodiment, the charging device 2 and the cleaning device 6 are further provided.

Next, the process cartridge 20 in this embodiment will be described in detail with reference to FIG.

The process cartridge 20 used in this embodiment is provided in a laser beam printer which is an electrophotographic image forming apparatus, which receives image information from a host computer and outputs it as a visualized image. A certain photosensitive drum 1, a developing means, a consumable item such as a developer (toner), and the like are integrated and are detachably replaceable with respect to the apparatus main body.

As shown in FIG. 2, the process cartridge 20 includes a photosensitive drum 1 as an image carrier, a charging roller 2 as a charging unit for uniformly charging the photosensitive drum 1, a developing device 4, and a photosensitive drum. 1. A cleaning device 6 including a cleaning blade 61 for cleaning the surface of the first recording medium 1 and a waste toner container 62 for containing the residual toner removed from the photosensitive drum 1 by the cleaning blade 61;
Is integrally configured and is detachably attached to an electrophotographic image forming apparatus main body (hereinafter, simply referred to as “apparatus main body”).

The developing device 4 includes a toner container 41 which is a developer container for containing the toner T which is a developer, a developer container 42 which is also a developer container and which is connected to the toner container 41, and a developing container 42. A developing roller 43 that is provided inside and is a developer bearing member as a developing means that is disposed opposite to the photosensitive drum 1, and a developing blade 44 that is a developer regulating member that contacts the developing roller 43 and regulates the toner layer thickness; And the toner T in the toner container 41 is stirred, and the developing container 42
An agitating member 45 that conveys the toner to the developing roller 43 therein is provided.

Before using the cartridge 20, a toner sealing member 46 is attached between the toner container 41 and the developing container 42. The toner sealing member 46 is provided so that the toner T does not leak even when a strong shock occurs during transportation of the process cartridge 20.
It is opened by the user immediately before mounting the process cartridge 20 in the apparatus main body.

In the laser beam printer of the electrophotographic image forming apparatus having the structure shown in FIG. 1, a laser scanner 3 which is a latent image forming means for irradiating a laser beam L corresponding to image information is provided above the process cartridge 20.
However, the transfer roller 5 which is a transfer member facing the photosensitive drum 1 is disposed below.

Regarding the image formation with the above-mentioned structure, FIG.
Similarly to the image forming apparatus shown in FIG. 3, the photosensitive drum 1 is uniformly charged by the charging roller 2, and the surface thereof is scanned and exposed by the laser light L emitted from the laser scanner 3 to form an electrostatic latent image of desired image information. It is formed. The electrostatic latent image is visualized as a toner image with toner attached by the action of the developing roller 43 and the like. In this example, an insulating magnetic one-component toner was used as the developer.

The laser beam printer provided with the process cartridge 20 of the present embodiment is provided with a developer remaining amount detecting means capable of successively detecting the remaining amount of toner in the developing device 4 as the toner is consumed.

In this embodiment, as shown in FIG. 2, the developing roller 43 is used as the developer remaining amount detecting means, and the plate sheet metal 47 is further used. The plate sheet metal 47 is
The developing device 4 is provided at a position facing the developing roller 43 over the entire area in the longitudinal direction of the developing device 4.

The plate sheet metal 47 can be used as the plate electrode without particular limitation as long as it is a material that can basically pass an electric current, but in the present embodiment, rust-resistant SUS is used as the material. ing.

The apparatus main body and the process cartridge 20 are provided with electric contacts (not shown), and when the process cartridge 20 is mounted in the apparatus main body, the plate metal plate 47 of the cartridge 20 and the apparatus main body are passed through the electric contacts. The remaining amount detection detector 100 (FIG. 3) therein is electrically connected.

Here, referring to FIG. 3, the cartridge 20
Remaining amount detection detection unit 1 when is normally attached to the device body
00 circuit configuration is shown.

In FIG. 3, when a predetermined AC bias is output from the developing bias circuit 48 as the developing bias applying means, the applied bias is applied to the developing roller 43 in the developing device 4.

The developing roller 43 and the plate sheet metal 47 serve as electrodes of the condenser, and the measurement value generated for the electrostatic capacitance between the developing roller 43 and the plate sheet metal 47, that is, the voltage value is digitally converted by the detection circuit 105, and the remaining amount. The measurement result is sent to the control unit arithmetic circuit 102, and the plate sheet metal 47
The relationship between the electrostatic capacity between the developing roller 43 and the developing roller 43 and the amount of toner is compared with a threshold table 103 that is related in advance, and is detected as a developer remaining amount detection result (toner remaining amount detection result) 104,
In this embodiment, the process cartridge 20 shown in FIG.
Storage means (process cartridge memory)
21 and the display means 106 provides the user with, for example, the remaining toner amount in the form of% display or the number of printable sheets.

In this embodiment, the developing bias as the applied bias applied from the developing bias power source 48 is 2
A bias in which an AC bias of about kHz and a DC bias of about -400V are superimposed is used.

Conventionally, the detection result of the remaining toner amount detection result 104 obtained by the above method is written in the main body memory or the process cartridge memory 21, and the write data is accessed. When a sudden change is shown, it is judged that the detection data has changed due to the influence of moisture absorption, noise reduction, etc., and it has been excluded.

However, when such a sequence is adopted, depending on the installation environment, the remaining toner amount may decrease without providing the user with the accurate toner remaining amount detection result 104, or the installation environment conditions may be different. If the change is gradual and continues to change within the threshold condition range that is not enough to be excluded, erroneous detection or inaccurate toner remaining amount data may be presented to the user.

Therefore, in the present invention, in the toner remaining amount detection detecting section 100 for detecting the toner remaining amount, the resistance value of the transfer roller 5, as the environment detecting means, is P in this embodiment.
TVC control (Programmable Transfer Voltage Contr
ol), the environmental change is detected according to the resistance value of the transfer roller 5 obtained from the detection value of
It is characterized by adding a correction to.

Further, in the present embodiment, the toner container 4 is determined from the voltage value generated between the developing sleeve 43 as the remaining amount detecting means and the sheet metal antenna 47 attached to the bottom surface of the developing container 42.
The remaining toner amount in 1 is measured. In this embodiment, a cartridge structure in which the toner weight when full is 100 g is used.

Here, the transfer roller 5 used in this embodiment.
Will be described. The structure of the image forming apparatus in this embodiment is as shown in FIG. 1, the process speed is 80 [mm / sec], and the conveying speed of the recording material P is 12 ppm. An ion conductive solid roller is used as the transfer roller 5, and its outer dimension is 15 mm in diameter.
Further, the resistance value of the transfer roller 5 is 1 × 10 ⁸ (Ω) under the condition of +2.0 kV applied in an environment of 25 ° C. and 60% of normal temperature and normal pressure.
And

First, the correlation between the environmental change and the PTVC control output value TrR which is the resistance value of the transfer roller 5 is confirmed. The environmental conditions at this time are three typical environments: high temperature and high humidity of 35 ° C 80%, normal temperature and normal humidity of 25 ° C 60%, and low temperature and low humidity of 1%.
It is carried out at 5 ° C and 10%.

Detection resistance value Tr of the transfer roller 5 at that time
As shown in Table 1, R is 1.7 × 10 ⁸ Ω (15
℃ 10%), 1.0 × 10 ⁸ Ω (25 ℃ 60%), 0.
It became 6 × 10 ⁸ Ω (35 ° C. 80%).

[0069]

[Table 1]

Here, a method of measuring the resistance value TrR of the transfer roller 5 as the environment detecting means will be described with reference to FIG. As shown in FIG. 4, a total pressure of 1.0 kg (500 g on one side) is applied to the aluminum cylinder 53 so that the aluminum roller 53 is brought into contact with the transfer roller 5 and rotated, and an arbitrary voltage V (for example, +2.0 k) is applied.
V) is applied to the transfer roller core metal 51 from the DC high-voltage power supply device 52 through the aluminum cylinder 53, the maximum and minimum values of the electric current generated at both ends of the resistance are read by the ammeter 54. An average value of current values flowing in the circuit is obtained from the read current values, and the resistance value TrR of the transfer roller 5 is calculated (measurement environment is normal temperature and normal pressure, 25 ° C. 60%).

On the other hand, in the case of the actual control of the main body, the resistance value TrR of the transfer roller 5 obtained by the measuring method shown in FIG.
In the ableTransfer Voltage Control), a voltage value V ′ necessary for energizing a predetermined target current is used, and the resistance value TrR ′ of the transfer roller 5 obtained according to the voltage value V ′ is used for control. There is.

That is, the resistance value TrR of the transfer roller 5 is not directly obtained by the measuring method shown in FIG. 4 each time the environment is detected. First, when the transfer bias is applied, it is determined by the PTVC control. The resistance value TrR ′ of the transfer roller 5 is obtained from the voltage value V ′.

The resistance value Tr obtained from this voltage value V '
Since R'has various values depending on the control circuit used,
In this embodiment, the voltage value V ′ obtained by the PTVC control in advance, and TrR ′ obtained from the voltage value V ′, and the resistance value TrR measured by the method described with reference to FIG.
Keep the correlation of. Then, the resistance value TrR correlated with the voltage value V ′ is used as the detection resistance value TrR. The resistance value TrR is as shown in Table 1.

Similarly, changes in the electrostatic capacity of the toner in three typical environments are confirmed. At this time, the toner weight is 100 g in an unused state, 50 g in 50% use, 80
%, 20 g of 3 kinds were used. The results are shown in Table 2. The difference in the absolute value of the output in each residual toner amount is large, but when the 25 ° C 60% environment is set as the reference, the difference from the reference value is the remaining toner amount. About 5V between 15 ° C 10% environment and 25 ° C 60% environment, 25 ° C 60% environment and 35 ° C 80%
It can be seen that it is almost constant between the environment and about 3V.

[0075]

[Table 2]

Therefore, when the resistance value TrR of the transfer roller 5 and the environmental variation value of the toner remaining amount detection result are plotted, it becomes as shown in FIG. 5, and the environmental variation value of the transfer roller resistance value TrR and the electrostatic amount in the toner remaining amount detection are shown. It was clarified that the environmental fluctuation value of capacity has linearity. Therefore, 25 ℃ 60
If a correction formula is made with% as a reference, it becomes like the formula 1.

[0077]

[Equation 1]

Here, ν represents a correction amount (V), and TrR
Represents the resistance value (Ω) of the transfer roller 5 obtained by the above method. In this embodiment, the toner amount detection result 104
A value obtained by subtracting the correction amount ν from the output value is detected and detected as a toner amount detection correction result 107, which is displayed on the display unit 106 toward the user. Now, let us check the environmental change transition of the remaining toner amount detection without the correction formula and the environmental change transition with the correction formula 1.

As a result, the developer collecting section 4 shown in FIG.
As can be understood from the toner remaining amount detection result 104 output value and the toner remaining amount detection result output value 107 after correction when the toner amounts in 1 and 42 are constant, the correction using the correction formula 1 is not performed. According to the experimental result, when the resistance value of the transfer roller 5 rises, the output value 104 of the toner remaining amount detection result also rises, that is, the environmental change is very large, and the possibility of erroneous detection is suggested. On the other hand, in the experimental result corrected by using the correction formula 1, the output value of the toner remaining amount detection result 107 does not change even if the resistance value of the transfer roller 5 rises, and the electrostatic capacitance of the toner changes due to environmental changes. It has been clarified that there is almost no effect.

In the correction method of this embodiment, the correction amount of the correction formula 1 is directly reflected on the output value of the toner remaining amount detection result 104 detected by the toner amount remaining amount detecting means. However, the correction method is not limited to this, and the correction amount is reflected in the remaining amount threshold table 103,
A method of changing the threshold value itself is also an effective method.

In the present embodiment, the toner remaining amount detecting means is described as a two-piece structure of the developing sleeve 43 and the sheet metal antenna 47 stretched on the floor inside the developing container 42, but the present invention is not limited to this. If the capacity of the toner container 41 reserved behind the developing container 42 is much larger than the capacity of the developing container 42, it is effective to install a sheet metal 47 for detecting the remaining amount of toner in the toner container 41. Is.

Further, the sheet metal structure, the outer shape of the developing sleeve and the like used in this embodiment are merely examples, and the present invention is not limited to these. Further, it should be added that the correction formula 1 is also an example.

As in the present embodiment, the toner residual amount detection result output is corrected in accordance with the resistance value of the transfer roller, so that even if the fine powder toner absorbs moisture, the toner with a very small error is obtained. The remaining amount detection control can be performed, and an accurate toner remaining amount display can be shown to the user.

The transfer roller, which is a transfer member, is not limited to the transfer roller which is provided in the image forming apparatus for monochromatic printing as shown in FIG. 1 and which transfers directly from the photosensitive drum to the recording medium. For example, a color image forming apparatus adopting an intermediate transfer system, which includes an intermediate transfer member, performs a primary transfer by superimposing images of a plurality of colors on the intermediate transfer member, and then secondarily transfers the images from the intermediate transfer member to a recording medium collectively. The present invention can also be applied to this case, and in this case, the transfer roller is provided as a primary transfer member or a secondary transfer member.

Second Embodiment In the first embodiment, as the environment detecting means, an environmental change of the transfer roller resistance value TrR is used to correct the toner remaining amount detection result output value, thereby making it possible to obtain an accurate environment-independent change. It has become possible to detect the remaining amount of toner.

In this embodiment, as the environment detecting means, in the on-demand fixing device, the toner remaining amount detection result output is corrected according to the start-up speed, which is the time until the target fixing temperature by temperature control is reached. Is added.

The present embodiment will be described below. In the electrophotographic image forming apparatus to which this embodiment is applied, Embodiment 1
Members having the same configurations and functions as those shown in FIGS. 1, 2, and 3 described in FIG.

FIG. 7 shows the structure of the heat fixing device 18 which is the fixing device according to the present invention. Heat fixing device 18 shown in FIG.
Is installed in an image forming apparatus such as a laser beam printer.
It is provided in a state similar to that of the fixing device 18 shown in FIG. 1, and has a resilient layer 82 formed by foaming heat resistant rubber such as silicone rubber or fluororubber or silicone rubber on the outside of the core metal 81. There is a roller 18b. Then, the releasable layer 8 made of PFA, PTFE, FEP or the like is formed on the surface of the elastic layer 82.
3 may be formed.

The fixing member 18a is composed of the following members. The fixing film 84 having a small heat capacity has heat resistance,
Thermoplastic polyimide, polyamideimide, PE
It is made of EK, PES, PPS, PFA, PTFE, FEP, etc. Further, in order to prevent offset and ensure the separability of the recording material P which is a recording medium, PFA and PT are provided on the surface layer.
It is a mixture of a heat-resistant resin such as FE and FEP having a good mold releasability or a single coating.

The heating heater H, which is provided inside the fixing film 84 and is composed of a thermistor 85, a heater substrate 86, and a heating element 87, melts and fixes the toner image T on the recording material P. Heat N '. The heat insulating support member 88 holds the heater H for heating and prevents heat radiation in the direction opposite to the nip N ′, and is formed of liquid crystal polymer, phenol resin, PPS, PEEK, or the like, and the fixing film 84. Has such a shape and size that it can be easily rotated in the direction of the arrow.

Further, since the fixing film 84 rotates while sliding on the fixed heating heater H (configurations 85, 86, 87) and the heat insulating support member 88 inside, the heating heater H and the heat insulating support member 88. It is necessary to suppress the frictional resistance between the fixing film 84 and the fixing film 84 to be small. Therefore, the heater for heating (configurations 85, 86, 87) and the heat insulating support member 88
A small amount of lubricant such as heat-resistant grease is interposed on the surface of the. This allows the fixing film 84 to rotate smoothly.

The heating heater H used in this embodiment is
One or a plurality of heat generating patterns 87 are provided on the surface of the ceramic substrate 86 such as Al ₂ O ₃ or AlN having high mechanical strength and thermal strength on the pressure roller 18b side. By energizing this heating pattern, the amount of heat required to fix the unfixed image T is obtained. Further, in order to perform control for giving a sufficient amount of heat, a temperature detection thermistor 85 for detecting the fixing temperature is provided on the non-heating side by contact or adhesion, and temperature adjustment is performed so as to maintain a predetermined target fixing temperature. ing.

Therefore, in this embodiment, the target fixing temperature required for fixing is set to 200 ° C., and using this fixing device 18, the rising time until the target fixing temperature is reached in the three main environments as in the first embodiment. To measure. In order to improve the accuracy of the experiment, the pre-energization detection temperature of the fixing device 18 is assumed to be room temperature during the measurement. Also, the heater H input voltage is 100
It is set to 50 Hz of V. As a result, as shown in Table 3, the higher the temperature and humidity, the shorter the rise time, and it is clear that there is a difference in the rise time depending on the environment.

[0094]

[Table 3]

Further, from the results shown in Table 3, 5 toner is used.
In the developing device 4 containing 0 g, the remaining toner amount detection means 104 detects the remaining toner amount detection result 104 from the electrostatic capacity between the developing roller 43 and the plate metal plate 47 in the same manner as in the first embodiment, and the fixing device rising time ( When a graph showing the relationship with the target fixing temperature arrival time) is obtained, as shown in FIG.
It became clear that there is almost linearity. In FIG. 8, only the results in three environments with the toner amount of 50 g are shown, but the toner amount of 100 g or 20 g as in the first embodiment is also shown by a graph having linearity.

From these graphs, the rise time s
(Sec) and the toner remaining amount correction amount ν2 (V), the correction formula 2 is determined as shown in formula 2. In this embodiment, the toner amount detection result 104 output value minus the correction amount ν2 is detected to be detected as the toner amount detection correction result 107, which is displayed to the user by the display means 106.

[0097]

[Equation 2]

FIG. 9 shows the toner remaining amount detection result 104 output value and the toner remaining amount detection result output value 107 after correction when the toner amounts in the developer collecting portions 41 and 42 are constant,
In the experiment result 104 in which the correction using the correction formula 2 is not performed, the toner amount detection result 1 is obtained when the rising time s becomes long.
The 04 output value also increased, and the environmental fluctuation was very large, which suggests the possibility of false detection. On the other hand, in the experimental result 107 corrected using the correction formula 2, the output value of the toner amount detection result 107 is constant even if the rising time s changes,
It has been clarified that the change in the electrostatic capacity of the toner caused by the environmental change has almost no effect.

From the actual transition, if the toner remaining amount in the developer collecting section is constant, the developer remaining amount detection result 107 corrected by using the correction formula 2 can obtain a constant output regardless of the environment. It has become possible.

In the correction method of this embodiment, the toner remaining amount detection result 107 is derived by reflecting the correction amount according to the correction formula 2 on the output value of the toner remaining amount detection result 104. However, the correction method is not limited to this,
A method of reflecting the correction amount on the remaining amount threshold value table 103 and changing the threshold value itself is also an effective method.

In the present embodiment, the description is made of the two sheets of the toner remaining amount detecting sheet metal, that is, the developing sleeve 43 and the sheet metal antenna 47 stretched on the floor in the developing container 42. However, the present invention is not limited to this. If the capacity of the toner container 41 reserved behind the developing container 42 is much larger than the capacity of the developing container 42, it is effective to install a sheet metal 47 for detecting the remaining amount of toner in the toner container 41. Is.

Further, the sheet metal structure, the outer shape of the developing sleeve and the like used in this embodiment are merely examples, and the present invention is not limited to these. Further, it should be added that the correction formula 2 is also an example.

In addition to the image forming apparatus provided with the process cartridge having the structure shown in FIG. 2, the present invention includes only one of a charging unit and a cleaning unit, a developing unit and a photosensitive drum. The present invention can also be applied to an image forming apparatus in which a process cartridge in which the above are integrated is provided, or an image forming apparatus in which the developing device is formed into a cartridge and can be independently attached and detached as a developing cartridge.

As described above, according to the image forming apparatus of the present invention, the toner remaining amount detection result is corrected in accordance with the resistance value of the transfer roller and the rising speed of the heating and fixing device, so that the temperature It is possible to obtain a constant and accurate toner residual amount detection result output value regardless of the installation environment such as humidity and humidity, and to notify the user of the accurate toner residual amount at all times.

[0105]

As described above, the image forming apparatus of the present invention is provided with a cartridge-type developing device provided therein,
Alternatively, in a developer remaining amount detecting method for detecting the remaining amount of the developer in the developer collecting portion of the process cartridge including the developing device, depending on the detection result of the environment detecting means for detecting the installation environment of the cartridge inside the main body of the image forming apparatus. By correcting the detected value of the residual developer amount detection result obtained by the residual developer amount detecting means, a change in the installation environment such as the temperature and humidity around the developing device or the process cartridge equipped with the developing device is performed. Regardless of the accurate remaining amount of the developer, the user can be always notified. Here, as the environment detecting means, it is possible to apply one that detects the installation environment by using the resistance value of the transfer member or by using the arrival time to the target fixing temperature of the fixing device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment of a process cartridge according to the present invention.

FIG. 3 is an explanatory diagram showing a circuit configuration of a developer remaining amount detection detection unit according to the present invention.

FIG. 4 is a schematic configuration diagram showing an embodiment of a transfer member according to the present invention.

FIG. 5 is a graph showing a relationship between a transfer roller resistance value and a toner remaining amount detection result output value before correction.

FIG. 6 is a graph showing a relationship between a transfer roller resistance value and a toner remaining amount detection result output value according to the present invention.

FIG. 7 is a schematic configuration diagram showing an embodiment of a fixing device according to the present invention.

FIG. 8 is a graph showing a relationship between a fixing device startup time and a toner remaining amount detection result output value before correction.

FIG. 9 is a graph showing the relationship between the fixing device startup time and the toner remaining amount detection result output value according to the present invention.

[Explanation of symbols]

Reference Signs List 1 photosensitive drum (image carrier) 2 charging roller pair (charging means) 4 developing device 5 transfer roller (transfer member) 6 cleaning device 18 fixing device 20 process cartridge 21 storage means 41 toner container (developer container) 42 developing container (Developer accommodating portion) 43 Developing roller (developer remaining amount detecting means) 47 Plate sheet metal (developer remaining amount detecting means) 48 Development bias power source 100 Developer remaining amount detecting detector 102 Arithmetic circuit 103 Threshold table 104 Toner remaining amount Detection result (developer remaining amount detection result) before correction 107 Toner remaining amount detection result (developer remaining amount detection result) After correction

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DA01 DA13 DA14 DA39 DD02                       DE07 DE10 ED24 ED25 EF04                 2H077 DA15 DA18 DA57 DA80 DA86                       GA02                 2H200 FA01 GA23 HA03 HB12 JA02                       JA30 JC00 PB05 PB27 PB28

Claims (8)

[Claims] 1. A main body of an image forming apparatus comprising a developing device having an image carrier and a developer accommodating portion for accommodating a developer for developing an electrostatic latent image on the image carrier to form a toner image. An image forming apparatus for forming an image on a recording medium, comprising: a detachable cartridge, and a developer remaining amount detecting means for detecting a developer remaining amount in the developer collecting section. An environment detection unit for detecting the installation environment inside the main body is provided, and the detection value of the developer remaining amount detection result obtained by the developer remaining amount detection unit is corrected according to the detection result of the environment detection unit. An image forming apparatus characterized by the above. 2. The image forming apparatus according to claim 1, wherein the developer remaining amount detection result is detected by using a threshold table. 3. According to the detection result of the environment detecting means,
The image forming apparatus according to claim 2, wherein the detection value of the developer remaining amount detection result is corrected by correcting the threshold value of the threshold value table. 4. A nip is formed facing the image carrier, the recording medium is held in the nip, and the toner image formed on the image carrier is transferred to the recording medium. The image forming apparatus according to claim 1, further comprising a transfer member, wherein the environment detecting unit detects the installation environment by using a resistance value of the transfer member. 5. An intermediate transfer member on which the toner image formed on the image carrier is primarily transferred, and a primary transfer for primarily transferring the toner image from the image carrier to the intermediate transfer member. A member and a secondary transfer member that secondarily transfers the toner image that has been primarily transferred to the intermediate transfer member to the recording medium, and the environment detecting unit includes the primary transfer member or the secondary transfer member. The image forming apparatus according to claim 1, wherein the installation environment is detected by using the resistance value of the image forming apparatus. 6. A fixing device for fixing an image formed on the recording medium by being heated until a predetermined target fixing temperature is reached, wherein the environment detecting means includes a fixing device for fixing the target fixing device. The installation environment is detected by using the arrival time until the temperature is heated to a temperature.
2 or 3 image forming apparatuses. 7. The image forming apparatus according to claim 1, wherein the cartridge is a process cartridge integrated with the image carrier. 8. The process cartridge according to claim 7, further comprising a charging unit that charges the image carrier and / or a cleaning device that cleans a developer on the image carrier. Image forming apparatus.