JPH08211694A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device which is the electrophotographic system image forming device provided with an intermediate transfer belt and which is constituted so that an excellent image can be always obtained by instructing the exchanging time of the belt. CONSTITUTION: This image forming device is provided with a latent image carrier 9 constituted so that a toner image is formed on the surface by successively executing an electrostatic charge action, an exposure action and a developing action, the intermediate transfer body 19 rotated while being brought into contact with the carrier 9, a first transfer means 20 transferring the toner image of the carrier 9 on the transfer body 19 at a transfer part where the carrier 9 and the transfer body 19 are brought into contact with each other and a second transfer means 23-1 transferring the toner image of the transfer body 19 on a recording medium. Besides, it is provided with residual potential detection means 50a and 50b detecting potential left on the carrier 9, a decision means deciding the life of the transfer body 19 based on the measured value of the detection means 50a and 50b and an information means 52 informing the end of the service life of the transfer body 19 based on the decided result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer and a facsimile machine.
In particular, the present invention relates to an image forming apparatus provided with a carrier that carries an object to be carried such as toner and transfer paper and conveys it to the next step. More specifically, the present invention relates to an image forming apparatus having a function of determining the end of life due to deterioration of an intermediate transfer belt or the like.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
An electrostatic latent image obtained by irradiating a photoconductor uniformly charged beforehand with optical image information such as reflected light from a document is visualized by toner supplied from a developing device. An image is formed by transferring and fixing the image on a transfer paper. In such a toner image transfer type electrophotographic image forming apparatus, the toner image formed on the photoconductor is provided with a charge having a polarity opposite to the charge polarity of the toner by the transfer charger from the back surface of the transfer paper. Therefore, the toner image is transferred to the transfer paper, or the toner image is once transferred from the photoconductor to the intermediate transfer belt or the drum and then transferred to the transfer paper (in the case of a full-color copying machine).

By the way, in a full-color copying machine, a transfer method is adopted in which toner images on a photoconductor are once transferred for each color on an intermediate transfer body (intermediate transfer belt) in a superimposed manner, and then are collectively transferred onto a transfer paper. Has been done. In the transfer method using the intermediate transfer belt, there is a retransfer position for transferring the image on the intermediate transfer belt onto the transfer paper, on the downstream side of the transfer position for transferring the toner image from the photoconductor onto the intermediate transfer belt. At the retransfer position, a transfer roller (paper transfer bias roller) is arranged to face the belt surface. The transfer roller is in contact with the belt driving roller via the belt, and transfer is performed when the transfer paper is passed between the transfer roller and the belt. The intermediate transfer belt has a role of electrostatically transferring the carried image by receiving supply of electric charges from the supply of electric charges, and is therefore made of a material having a certain electric resistance. When the toner image is transferred onto the transfer paper, it is desirable that the transfer efficiency is 100%, but in reality, the transfer efficiency is often lowered due to environmental conditions, paper quality, thickness, electric resistance and the like of the transfer paper. Further, the intermediate transfer belt has a relatively large environmental dependency, and the transfer belt deteriorates due to electrical fatigue due to long-term use, which causes deterioration of image quality.

Conventionally, by providing a reinforcing member (reinforcing tape) of a transfer belt or a meandering prevention belt as in the technique disclosed in Japanese Patent Laid-Open No. 5-289535, a belt crack (belt end crack), It was controlling the waviness and the growth. That is, in the above conventional example, when the above phenomenon occurs, it is determined that the belt has reached the end of its life. However, even if the mechanical life can be extended, the intermediate transfer belt is gradually deteriorated and fatigued electrically due to discharge during transfer, etc., due to long-term use. Therefore, the quality of the transferred image is also deteriorated. In this way, the inventor concludes that it is important to determine the belt life based on the quality of the electrical transfer characteristic, that is, the electrostatic characteristic other than the mechanical characteristic, in order to prevent the deterioration of the image quality. The present invention has been completed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and is an electrophotographic image forming apparatus provided with an intermediate transfer belt, for example, an intermediate transfer belt due to electrostatic fatigue caused by long-term use. It is an object of the present invention to provide an image forming apparatus which detects the degree of deterioration of the belt, determines the end of life based on the detection result, indicates the belt replacement timing, and thus always obtains a good image. . INDUSTRIAL APPLICABILITY The present invention is common to all the carriers that electrostatically carry objects to be carried such as toner and transfer paper and convey them to the next step. An image carrier (photoconductor drum, photoconductor belt, etc.) that carries the toner image by carrying the imaged toner image and being driven to rotate to the next process such as a transfer process, and transferred from the image carrier An intermediate transfer member (intermediate transfer belt, etc.) that conveys a toner image by being rotationally driven until a step of carrying a toner image and transferring it to a transfer target such as transfer paper, or a transfer paper or a transfer paper holding a toner image Examples of the belt include a conveyor belt that carries the supported object and is rotatably driven until the next step such as a transfer step or a fixing step to convey the supported object.

[0006]

In order to achieve the above object, the invention according to claim 1 is a latent image carrier on which a toner image is formed on a surface by sequentially performing charging, exposure and development, and the latent image carrier. An intermediate transfer member that rotates while in contact with the intermediate transfer member, a first transfer unit that transfers the toner image on the latent image carrier to the intermediate transfer member at a transfer portion where the latent image carrier and the intermediate transfer member contact each other, An image forming apparatus having a second transfer means for transferring the toner image on the transfer body onto a recording medium, and a residual potential detection means on the latent image carrier for detecting a potential remaining on the latent image carrier. A determining means for determining the life of the intermediate transfer member based on the measurement value of the residual potential detecting means and a notifying means for notifying the end of the life are provided.

According to the second aspect of the invention, a latent image carrier on which a toner image is formed by sequentially performing charging, exposure and development, and an intermediate transfer member which rotates while being in contact with the latent image carrier. A first transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at a transfer portion where the latent image carrier and the intermediate transfer body are in contact with each other; In an image forming apparatus having second transfer means for transferring the latent image on the latent image carrier, the first detecting means for detecting the potential remaining on the latent image carrier and the latent image potential formed on the latent image carrier. A second detection means for detecting
Determination means for determining the life of the intermediate transfer member based on the detection results of the first detection means and the second detection means,
And a notifying unit for notifying the end of life.

According to a third aspect of the present invention, a latent image carrier on which a toner image is formed by sequentially performing charging, exposure and development, and an intermediate transfer member which rotates while being in contact with the latent image carrier. A first transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at a transfer portion where the latent image carrier and the intermediate transfer body are in contact with each other; An image forming apparatus having a second transfer device for transferring the toner image onto the intermediate transfer member, and detecting the amount of toner remaining on the latent image carrier after the toner image is transferred onto the intermediate transfer member; An image forming apparatus comprising: a unit, a determining unit that determines the life of the intermediate transfer member based on the detection result of the transfer residual toner adhesion amount detecting unit, and a notifying unit that notifies the end of the life.

According to a fourth aspect of the invention, a latent image carrier on which a toner image is formed by sequentially performing charging, exposure and development, and an intermediate transfer member which rotates while being in contact with the latent image carrier. A first transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at a transfer portion where the latent image carrier and the intermediate transfer body are in contact with each other; An image forming apparatus having a second transfer unit for transferring the toner image onto the latent image carrier before the transfer of the toner image onto the intermediate transfer member; A second method for measuring the amount of toner remaining on the latent image carrier after the toner image is transferred to the intermediate transfer member
And a determining means for comparing and calculating the measured values by the first and second measuring means to calculate a transfer rate and determining the life of the intermediate transfer member based on the calculation result of the transfer rate.
And a notifying unit for notifying the end of life.

According to a fifth aspect of the present invention, a determination is made to determine the life of the intermediate transfer member by detecting the current flowing through the first transfer means and the member attached to the vicinity of the transfer portion of the second transfer means. And a notifying means for notifying the end of life.

[0011]

According to the present invention, the residual potential on the photoconductor is measured by the residual potential detection means (electrometer, etc.) provided, and the residual photoconductor is used when an intermediate transfer member having normal characteristics is used. By comparing the electric potential with the measured value, deterioration (for example, resistance decrease) of the intermediate transfer belt can be detected easily, with high sensitivity and accuracy, and the life of the intermediate transfer belt can be determined and notified.

According to a second aspect of the present invention, the first detecting means for detecting the potential remaining on the latent image carrier and the second detecting means for detecting the latent image potential formed on the latent image carrier. A detecting means, and a judging means for judging the life of the intermediate transfer member based on the detection results of the first detecting means and the second detecting means; and a notifying means for notifying the end of the life. Therefore, by measuring the latent image potential formed on the photoconductor and the residual potential remaining on the photoconductor with detection means (electrometer, etc.), deterioration of the intermediate transfer belt (for example, reduction in resistance) can be prevented. It is possible to accurately detect and determine the life of the intermediate transfer belt.

According to the third aspect of the present invention, the transfer residual toner adhesion amount detecting means for detecting the toner adhesion amount remaining on the latent image carrier after the toner image is transferred to the intermediate transfer member, and the transfer residual toner adhesion Since the determination means for determining the life of the intermediate transfer member based on the detection result of the amount detection means and the notification means for notifying the end of the life are provided, the toner image remains on the photoconductor after the transfer of the toner image to the intermediate transfer belt. The transfer residual toner adhesion amount is measured by a transfer residual toner adhesion amount detection means (for example, a reflection type optical sensor), and the intermediate transfer belt is deteriorated (for example, resistance is decreased).
It is possible to determine the life of the intermediate transfer belt by accurately detecting the above. Further, in this case, since the toner concentration sensor equipped to measure the toner concentration after development can also be used, the same flow can be used without newly designing the circuit, and the controllability of the sensor is also improved. It's easy.

According to a fourth aspect of the present invention, there is provided a first measuring means for detecting a toner adhesion amount on the latent image carrier before the toner image is transferred onto the intermediate transfer body, and the toner on the intermediate transfer body. The transfer rate is calculated by comparing and calculating the second measurement means for measuring the toner adhesion amount remaining on the latent image carrier after the image transfer and the measurement values by the first and second measurement means. Since the determination means for determining the life of the intermediate transfer member based on the calculation result of and the notification means for notifying the end of the life are provided, the toner adhesion amount on each photoconductor before and after the toner image transfer onto the intermediate transfer belt is calculated. The measured value is converted into a transfer rate, and from the calculation result of the transfer rate, the characteristic variation (for example, resistance decrease) of the intermediate transfer belt is accurately detected, and the intermediate value is obtained without being affected by the toner charge amount or the adhesion amount. The life of the transfer belt can be determined.

According to a fifth aspect of the present invention, a determination is made to determine the life of the intermediate transfer member by detecting a current flowing through a member attached to the first transfer means and a member provided near the transfer portion of the second transfer means. Since the means and the notifying means for notifying the end of the life have been provided, by measuring the current flowing through the member provided in the vicinity of each transfer portion, deterioration of the intermediate transfer belt based on the measured value (for example, resistance decrease) ) And the like can be accurately detected to determine the life of the intermediate transfer belt. In other words, regardless of the transfer to the intermediate transfer belt or the transfer to the paper, the current flowing through the conductor attached near the transfer portion is measured, so that no special sensor or jig is required. It is possible to always obtain stable determination results. In particular,
High reliability because there is no influence of sensor failure or erroneous detection.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic configuration explanatory view of an example of a color copying apparatus to which the present invention is applied, and FIG. 2 is an enlarged view around a photoconductor and an intermediate transfer belt. A color image reading device (hereinafter, referred to as a color scanner) 1 forms an image of an original 3 on a color sensor 7 via an illumination lamp 4, a mirror group 5, and a lens 6 to obtain color image information of the original. For example
It reads for each color separation light of blue, green, red and converts it into an electric image signal. The color sensor 7 includes B, G, and
It is composed of an R color separation means and a photoelectric conversion element such as a CCD, and simultaneously reads three colors. Based on the B, G, and R color-separated image signal intensity levels obtained by the color scanner 1, color conversion processing is performed by an image processing unit (not shown),
Black (hereinafter referred to as Bk), Cyan (hereinafter referred to as C), Magenta (hereinafter referred to as M), Yellow (hereinafter referred to as Y)
That is) color image data. Thus obtained B
The k, C, M, and Y color image data are visualized by a color image recording device (hereinafter referred to as a color printer) 2 described below to form a final color copy. In addition, B
The operation system of the color scanner 1 for obtaining the k, C, M, and Y image data is that the illumination / mirror optical system is moved to the left in FIG. 1 in response to the scanner start signal in time with the operation of the color printer 2. The original is scanned to obtain image data of one color for each scanning. By repeating this operation four times in total, sequential four-color image data is obtained. Then, each time, the image is sequentially visualized by the color printer 2, and the images are superposed to form a four-color full-color image.

Next, the outline of the color printer 2 will be described. The writing optical unit 8 converts the color image data from the color scanner 1 into an optical signal, performs optical writing corresponding to the original image, and forms an electrostatic latent image on the photosensitive drum 9. The unit 8 includes a laser 8-1, a light emission drive control unit (not shown), a polygon mirror 8-2, a rotation motor 8-3 for the polygon mirror 8-2, an f / θ lens 8-4, a reflection mirror 8-5, and the like. It is composed of. The photoconductor drum 9 rotates counterclockwise as indicated by the arrow, but around the photoconductor drum 9, a photoconductor cleaning unit 10, a charge eliminating lamp 11, a charger 12, a potential sensor 13, a Bk developing device 14, and a C developing device 1 are provided.
5, an M developing device 16, a Y developing device 17, a developing density pattern detector 18, an intermediate transfer belt 19 and the like are arranged. Each developing device rotates a developing sleeve (14-) which rotates by bringing the brush of the developer into contact with the surface of the photoconductor 9 in order to develop the electrostatic latent image.
1, 15-1, 16-1, 17-1) and a developing paddle (14-2, 14-2, which rotates to draw up and agitate the developer).
15-2, 16-2, 17-2) and the toner concentration detection sensor (14-3, 15-3, 16-3, 17) of the developer.
-3) etc.

Now, in the standby state, all four developing units are
Although the agent on the developing sleeve is in the state of cutting off (development inoperative), the order of developing operation (color image forming order) is B.
The case of k, C, M, and Y will be described. However, the image forming order of the present invention is not limited to this. When the copy operation is started, the color scanner 1 starts reading the Bk image data at a predetermined timing, and the optical writing by the laser beam is performed based on the image data.
Latent image formation begins. In order to enable development from the tip of the Bk latent image, the developing sleeve 14-1 is started to rotate and the agent is raised before the latent image tip reaches the developing position of the Bk developing device 14. The Bk latent image is developed with Bk toner. After that, the developing operation of the Bk latent image area is continued, but when the trailing edge of the latent image passes the Bk developing position, the agent spike on the Bk developing sleeve 14-1 is promptly cut off, and the developing operation is disabled. To do. This is completed at least before the leading edge of the C latent image by the next C image data arrives. It should be noted that the brush cutting is performed by switching the rotation direction of the developing sleeve 14-1 to the opposite direction to that during the developing operation.

The Bk toner image formed on the photoconductor 9 is transferred onto the surface of the intermediate transfer belt 19 which is driven at the same speed as the photoconductor. The belt transfer is performed by the photoconductor 9 and the intermediate transfer belt 1.
This is done by applying a predetermined bias voltage to the transfer bias roller 20 in the contact state 9. For the intermediate transfer belt 19, Bk, which is sequentially formed on the photoconductor 9,
The toner images of C, M, and Y are sequentially aligned on the same surface to form a belt transfer image of four-color superimposition, and then they are collectively transferred to a transfer paper. The structure of this intermediate transfer belt unit,
The operation will be described later. By the way, B on the side of the photoconductor 9
Although the process proceeds to the C process after the k process, the reading of the C image data by the color scanner 1 is started at a predetermined timing, and the C image is formed by writing the laser light with the image data. In the C developing device 15, rotation of the developing sleeve 15-1 is started to pass the developing agent after the trailing edge of the previous Bk latent image passes and before the leading edge of the C latent image reaches the developing position. The ears are raised and the C latent image is developed with C toner. After that, the development of the C latent image area is continued, but when the trailing edge of the latent image passes, the brush cutting on the C developing sleeve 15-1 is performed as in the case of the Bk developing device. This is also completed before the leading edge of the next M latent image arrives. Note that the steps of M and Y are the same as the steps of Bk and C in the operations of reading image data, forming a latent image, and developing, respectively, and therefore description thereof will be omitted.

Next, the transfer belt unit will be described. The intermediate transfer belt 19 is stretched around a drive roller 21, a belt transfer bias roller 20, and a driven roller group, and is driven and controlled by a drive motor (not shown) as described later. The belt cleaning unit 22 includes a brush roller 22-1, a rubber blade 22-2, a belt contact / separation mechanism 22-3, and the like.
While the second, third, and fourth colors are transferred on the belt after the image is transferred on the belt, they are separated from the belt surface by the contact / separation mechanism 22-3. The paper transfer unit 23 includes a paper transfer bias roller 23-1, a roller cleaning blade 23-
2 and a belt contact / separation mechanism 23-3 and the like.

The bias roller 23-1 is normally separated from the surface of the belt 19, but the timing of transferring the superimposed images of four colors formed on the surface of the intermediate transfer belt 19 onto the transfer paper is adjusted. The roller 23-1 is pressed by the contact / separation mechanism 23-3 and a predetermined bias voltage is applied to the roller 23-1 to perform transfer to the paper. The transfer paper 24 is fed by the paper feed roller 25 and the registration roller 26 at the timing when the leading edge of the four-color superimposed image on the intermediate transfer belt surface reaches the paper transfer position.

The moving method of the intermediate transfer belt 19 is a constant speed forward movement method, a skip forward movement method, as an operation method after the belt transfer of the Bk toner image of the first color is completed up to the rear end portion.
A reciprocating (quick return) method is conceivable, but one of these methods or a combination of efficient methods depending on the copy size (in terms of copy speed, etc.) is used. The transfer paper 24 on which the four-color superimposed toner images are collectively transferred from the surface of the intermediate transfer belt is fixed by the paper transport unit 27 to the fixing device 28.
Then, the toner image is melted and fixed by the fixing roller 28-1 and the pressure roller 28-2, which are controlled to a predetermined temperature, and is carried out to the copy tray 29 to obtain a full-color copy. At the time of repeat copy, the operation of the color scanner 1,
In addition, the image formation on the photoconductor 9 is performed on the second sheet Bk at a predetermined timing after the first sheet Y (fourth color) image process.
(First color) Go to the image process. In addition, the intermediate transfer belt 19
In the case of, the second Bk toner image is belt-transferred to the area whose surface is cleaned by the cleaning unit 22, following the batch transfer process of the first four-color superimposed image onto the transfer paper. . After that, the same operation as the first sheet is performed.

The transfer paper cassettes 30, 31, 32,
The transfer papers 33 of various sizes are stored in the paper 33, and are fed and conveyed toward the registration rollers 26 at a timing from a storage cassette of paper of a size designated by an operation panel (not shown). Reference numeral 34 is a manual paper feed tray for OHP paper, thick paper, or the like. In the above, the copy mode for obtaining four full colors has been described, but in the case of the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. In the single-color copy mode, until the predetermined number of sheets are finished, only the developing device of that color is in a developing operation (agent stand) state, and the intermediate transfer belt 19 remains in contact with the surface of the photoreceptor 9. The copying operation is performed in a state where the belt cleaner 22 is driven at a constant speed in the forward direction and the belt cleaner 22 is still in contact with the belt 19. The transfer paper ejected from the fixing device 28 is ejected to a paper ejection tray 29 mounted outside the printer.

FIG. 3 (a) is a schematic view showing the principle of the first embodiment of the present invention, and the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. In this embodiment, a photoreceptor (latent image carrier) 9 on which a toner image is formed on the surface by sequentially performing charging, exposure and development, and an intermediate transfer body 19 which rotates while being in contact with the photoreceptor 9. On the intermediate transfer member 19, a first transfer unit (belt transfer bias roller) 20 for transferring the toner image on the photosensitive member onto the intermediate transfer member at a transfer portion where the photosensitive member 9 and the intermediate transfer member 19 are in contact with each other. In the image forming apparatus having the second transfer means 23-1 for transferring the toner image onto the recording medium, the latent image carrier residual potential detecting means (surface potential probe) for detecting the potential remaining on the photoreceptor. ) 50a, a judgment circuit (judging means) 51 for judging the life of the intermediate transfer member 19 based on the measured value of the residual potential detecting means 50a, and an operation based on the judgment result by the judgment circuit 51 to reach the end of the life. Report Configuration that includes a display section (notification means) 52 which is characteristic.

That is, the residual potential detecting means 50 on the latent image carrier.
Reference numeral a denotes a surface potential probe arranged downstream of the position of the transfer roller 20 for detecting the potential remaining on the photoconductor after the transfer, and the discriminating circuit 51 stores the latent image carrier on the latent image carrier in a storage unit (not shown). Holds the data for determining the life of the intermediate transfer belt 19 based on the residual potential value of the intermediate transfer belt 19, and the life of the intermediate transfer belt based on the measurement result of the residual potential detecting means 50a on the latent image carrier. To judge. In other words, the transfer rate of the intermediate transfer belt is converted and calculated based on the measurement result, and when the determination result indicates that the service life has arrived, the determination circuit 51 outputs a display signal to the display unit 52 to indicate the service life has expired. Display the display (lamp lighting, voice display, etc.).

That is, for example, the surface potential of the photoconductor 9 is -450V when the potential of the non-image portion is -650V. The negatively charged toner image on the image portion of the photoconductor 9 is transferred to an intermediate transfer belt (for example, a fluorine-based seamless belt having a surface resistance of 10 ^8).
To transfer the 10 about ¹⁰ Omega) on, a voltage of + 1200 V to the belt transfer bias roller 20. When the residual potential of the photoconductor immediately after the transfer was measured by the surface potential probe 50a, the residual potential of the photoconductor was +50 V, and the obtained image was good.

Further, when the intermediate transfer belt 19 deteriorates due to electrostatic fatigue and the resistance thereof decreases due to long-term use and the like, the residual potential of the photoreceptor is measured in the same manner as above. The potential was + 300V. The state of the image obtained by the image forming operation performed under such conditions shows the lower limit of the favorable image area. That is, FIG. 4 is a diagram showing a correspondence relationship between the residual potential (V) on the photoconductor and the quality of the obtained image quality. In this example, +30.
The quality of image quality is divided with 0 V as a boundary. It should be noted that +300 V shown as a value indicating the upper limit of the residual potential of the photoreceptor required to obtain a good image is just an example.

Therefore, in the present invention, when the surface potential probe 50a detects that the residual potential of the photoconductor has exceeded the allowable value of +300 V, the discrimination circuit 5 is detected.
No. 1 has reached the end of its life and it is time to replace it, and the display unit 5 indicates that it has reached the time to replace the intermediate transfer belt.
The control signal for displaying on 2 is output. In this embodiment, the belt transfer bias roller 20 has a +1200
Although the case where V is applied has been described, the present invention is not limited to this, and when the applied voltage is different, the value indicating the upper limit of the residual potential of the photoconductor is also different. The discrimination circuit 51 includes, for example, a CPU, a ROM, a RAM,
A control unit having an I / O port, a data bus, etc. is used.

FIG. 3B is a modification of FIG. 3A. In addition to the surface potential probe (first detecting means) 50a, a latent image potential is provided on the upstream side of the transfer bias roller 20. Surface potential probe (second detecting means) 50b for detecting
May be arranged, and the determination circuit 51 may determine whether or not the measured value exceeds the upper limit value of the residual potential of the photoconductor. The surface potential probe 50b is the surface potential probe 50a.
May be used in combination, the measured values from both may be used in combination for determination, or the surface potential probe 50b may be used alone.
The image obtained as a result of exchanging the belt with a new one based on the notification of the end of life based on the above determination results was a good image.

Next, FIG. 5 is an explanatory view of the structure of another embodiment of the present invention. In this embodiment, a photoreceptor (on which a toner image is formed on the surface by sequential charging, exposure and development) Latent image carrier) 9, intermediate transfer belt 19 that rotates while being in contact with photoreceptor 9, photoreceptor 9 and intermediate transfer belt 1
First transfer means (belt transfer bias roller) 20 for transferring the toner image on the photoconductor onto the intermediate transfer belt at the transfer portion which is in contact with 9, and the toner image on the intermediate transfer belt 19 is transferred onto the recording medium. Second transfer means 23-1
In the image forming apparatus having
Transfer residual toner adhesion amount detection means 60a for detecting the amount of toner adhesion remaining on the photoconductor after the transfer of the toner image onto the photoreceptor, and the life of the intermediate transfer belt based on the detection result of the transfer residual toner adhesion amount detection means 60a. Judgment circuit (judgment means) for judgment
The configuration is characterized by including 51 and a display unit (informing means) 52 for notifying the end of life.

This transfer residual toner adhesion amount detecting means 60a
Is composed of, for example, a reflection type optical sensor, and detects the amount of transfer residual toner adhered by the value of the amount of light received by the light receiving element that receives the light emitted from the light emitting element. The value of the proper amount of adhesion is held in the discriminating circuit 51 as a reference value, and when the value of the amount of received light exceeds this reference value, the resistance value of the intermediate transfer belt 19 is not within the proper range. Below the resistance value)
Then, the display unit 52 is instructed to perform a display operation.
That is, the toner adhesion amount on the photoconductor is measured and converted into a transfer rate, and deterioration of the intermediate transfer belt (for example, resistance decrease) is accurately detected from the calculation result of the transfer rate to determine the life of the intermediate transfer belt. Can be determined. For this reason, an operator who sees or hears the arrival time of the replacement time can replace the belt at an appropriate time, and it is possible to prevent copying with poor image quality.

Next, FIG. 6 is a structural explanatory view of another embodiment of the present invention, which is a modification of FIG. That is, in this embodiment, the first measuring means 60a for detecting the toner adhesion amount (toner amount of the developed image) on the photoconductor 9 before the toner image transfer to the intermediate transfer belt 19, and the toner to the intermediate transfer belt. Second measuring the amount of toner remaining on the photoconductor after the image transfer
Of the measuring means 60b and the measuring values of the first and second measuring means are calculated to calculate the transfer rate, and the life of the intermediate transfer belt is judged based on the calculation result of the transfer rate. It is characterized by a configuration including a means) 51 and a display unit 52 for notifying the end of life (replacement time).

That is, even if the transfer electric field by the belt transfer bias roller 20 is constant, the transfer rate varies depending on the amount of toner adhered to the photosensitive member 9 before transfer and the amount of toner charge. In FIG. 7, the horizontal axis indicates the toner adhesion amount (mg / cm ² ) before transfer, which is developed on the photoreceptor.
FIG. 6 is a diagram showing the relationship between the toner adhesion amount on the photoconductor and the transfer residual toner amount by taking the photoconductor residual toner amount (transfer residual toner image) after the toner image is transferred to the intermediate transfer belt 19 on the vertical axis. .

In the figure, the characteristic A is the characteristic when a transfer voltage of 1200 V is applied to the belt transfer bias roller 20 and the toner having the normal charge amount (15 μc / g) is transferred onto the photosensitive member. Shows. Characteristic B shows a characteristic when a transfer voltage of 1200 V is applied to the belt transfer bias roller 20 and a toner having a relatively high charge amount (20 μc / g) is transferred onto the photoconductor. Characteristic C is a value in which a transfer voltage of 1200 V is applied to the belt transfer bias roller 20 and the charge amount is relatively low (10 μc /
The characteristics when the toner of g) is transferred onto the photoconductor are shown. The shaded area in the figure indicates the proper transfer area. As described above, due to the amount of adhesion of the toner forming the toner image developed on the photosensitive member, a situation in which a good transfer rate cannot be obtained at a certain portion occurs.

On the basis of such a phenomenon, in the present invention, for example, the value of the adhesion amount shown on the horizontal axis is 0.1 to 1.2 mg.
Within the range of / cm ² , a plurality of reference patterns (gray scale = toner patterns whose density increases gradually toward one direction) with different toner adhesion amounts are formed on the photoconductor, and the density of each part of this reference pattern is increased. Is compared with the stored reference value. That is, an image forming operation for measurement is performed at the start-up of the image forming apparatus or every time when a predetermined number of copies (for example, 150 sheets) is executed, and the belt transfer before and after the operation is performed. The amount of toner adhering to the photoconductor is measured by the optical sensors 60a and 60b, and the transfer rate is calculated based on the measured value in the discrimination circuit 51. If the result exceeds the reference value, the intermediate transfer is performed. The resistance value of the belt 19 is not within the proper range (below the proper resistance value)
Then, the display unit 52 is instructed to perform a display operation.
For this reason, the operator who sees or hears the indication of the arrival of the replacement time can replace the belt at an appropriate time, and it is possible to prevent copying with poor image quality. The reference pattern is stored in a memory or the like of the main control unit of the image forming apparatus, and the writing unit 8 outputs the reference pattern onto the photoconductor to form a latent image on the photoconductor. The position where the reference pattern is formed may be an image forming area on the photoconductor, a non-image forming area, or an area extending over both areas. Since the method of measuring the toner amount by the reflection type optical sensor shown in FIGS. 5 and 6 is known, the details will not be described.

Next, in each of the above embodiments, before transfer,
Alternatively, and / or the residual potential on the latent image carrier after transfer, the transfer residual toner adhesion amount, the pre-transfer toner adhesion amount, etc. are measured, and the measurement results are compared with a reference value or converted into the transfer rate of the intermediate transfer belt. Therefore, the deterioration of the intermediate transfer belt such as a decrease in resistance and the life expiration state are determined to notify the replacement time, but the decrease in resistance is measured by measuring the value of the current flowing through the intermediate transfer belt. You may do it. That is, FIG. 8 is a schematic view of an embodiment for realizing such a measuring method. In this embodiment, the belt transfer bias roller 20 (first transfer means) and the paper transfer bias roller (second transfer means) are used. Determination means 51 for determining the life of the intermediate transfer belt by detecting the value of the current flowing through a member provided near the transfer portion in the transfer means), for example, the driven roller 65 (earth roller, etc.), and the display portion for notifying the end of the life. And 52.

The current value data serving as a reference for determining the end of life is stored in the storage unit such as the ROM of the determination circuit 51, and the current value obtained by the measurement is used as the reference data (appropriate current range). If the current value exceeds the appropriate range, it is determined that the electric resistance value of the intermediate transfer belt 19 has decreased, and the arrival of the replacement time is indicated on the display unit 52.
Let me know. This means that the paper transfer bias roller 23
In the vicinity of −1, the same configuration can be performed and the obtained measurement result can be similarly used. The attached member may be a member other than the above-mentioned roller, and may be, for example, a sliding terminal specially provided for sliding contact with an appropriate position of the intermediate transfer belt 19.

According to this embodiment, the current flowing through the conductor attached near the transfer portion is measured regardless of the transfer to the intermediate transfer belt or the transfer to the paper. It is possible to always obtain a stable determination result without requiring. In particular, it is highly reliable because it is not affected by sensor failure or erroneous detection.

Further, the present invention is common to all the carriers that electrostatically carry objects to be carried such as toner and transfer paper, and convey them to the next step. Specific examples of the carriers are as follows. , An image carrier (a photoconductor drum, a photoconductor belt, etc.) that carries the toner image visualized in the developing process and is driven to rotate to the next process such as a transfer process, and the image carrier The intermediate transfer member (intermediate transfer belt, etc.) that conveys the toner image by being driven to rotate until the process of carrying the transferred toner image from the body and transferring it to the transfer target such as transfer paper, or the transfer paper or toner image An example of the carrier belt is a carrier belt that carries the held object such as the transfer paper and rotates the driven object until the next step such as a transfer step or a fixing step. Further, in the above embodiment,
Although the bias roller is shown as the transfer unit, this is only an example, and the present invention is also applicable to an image forming unit using the transfer unit including a transfer charger.

[0040]

According to the first aspect of the present invention, the latent image carrier residual potential detecting means (first detecting means) 50a for detecting the potential remaining on the latent image bearing body (photoconductor) 9 is provided. A determination unit (determination circuit) 51 that determines the life of the intermediate transfer member (intermediate transfer belt) 19 based on the measurement value of the residual potential detection unit 50a, and a notification unit (display unit) 5 that notifies the end of the life.
2 and. Then, the residual potential on the photoconductor is measured by an attached residual potential detecting means (electrometer, etc.) 50a, and the residual potential of the photoconductor and the measured value when an intermediate transfer member having a normal characteristic is used are compared. As a result, deterioration (for example, reduction in resistance) of the intermediate transfer belt can be easily detected with high sensitivity and accuracy, and the life of the intermediate transfer belt can be determined and notified.

According to the second aspect of the invention, the first detecting means 50a for detecting the potential remaining on the latent image carrier 9 is provided.
And second detection means 50b for detecting the latent image potential formed on the latent image carrier, based on the detection results of the first detection means and / or the second detection means. The latent image potential formed on the photoconductor and the residual potential remaining on the photoconductor are measured by detecting means (electrometer, etc.), respectively, to determine the normal characteristics. Since the residual potential of the photosensitive member and the measured value when the intermediate transfer member having the above are used are compared, it is possible to detect deterioration (for example, decrease in resistance) of the intermediate transfer belt with high accuracy and sensitivity, and Can be determined.

According to the third aspect of the present invention, the transfer residual toner adhesion amount remaining on the photoconductor after the toner image is transferred onto the intermediate transfer belt is measured by the transfer residual toner adhesion amount detecting means (for example, a reflection type optical sensor). Since the measurement result is compared with the reference value, deterioration of the intermediate transfer belt (for example, reduction in resistance) or the like can be accurately detected and the life of the intermediate transfer belt can be determined. In this case, the toner density sensor equipped to measure the toner density after development can also be used, and the data obtained at the time of toner density detection can be used as is, so a new circuit design is required. The same flow can be used, and the controllability of the sensor is easy.

According to a fourth aspect of the present invention, there is provided a first measuring means for detecting the toner adhesion amount on the latent image carrier before the toner image is transferred onto the intermediate transfer member, and the toner on the intermediate transfer member. The transfer rate is calculated by comparing and calculating the second measurement means for measuring the toner adhesion amount remaining on the latent image carrier after the image transfer and the measurement values by the first and second measurement means. A determination unit or the like for determining the life of the intermediate transfer member based on the calculation result of is measured, and the toner adhesion amount on each photoconductor before and after the transfer of the toner image to the intermediate transfer belt is measured and converted into a transfer rate, From the calculation result of the rate, it is possible to accurately detect the characteristic variation (for example, resistance decrease) of the intermediate transfer belt and to determine the life of the intermediate transfer belt without being influenced by the charge amount and the adhesion amount of the toner.

According to a fifth aspect of the present invention, a member (existing roller or the like) attached near the transfer portion of the first transfer means (belt transfer bias roller) and the second transfer means (paper transfer bias roller). ) To determine the life of the intermediate transfer member by detecting the current flowing, to the notification means for notifying the end of the life, measuring the current flowing through the member provided in the vicinity of each transfer portion, By comparing the measured value with the normal value, deterioration of the intermediate transfer belt (for example, resistance decrease) or the like can be accurately detected based on the comparison determination result, and the life of the intermediate transfer belt can be determined. In other words, regardless of the transfer to the intermediate transfer belt or the transfer to the paper, the current flowing through the conductor attached near the transfer portion is measured, so that no special sensor or jig is required. It is possible to always obtain stable determination results. In particular,
High reliability because there is no influence of sensor failure or erroneous detection.

[Brief description of drawings]

FIG. 1 is an overall configuration explanatory diagram of an image forming apparatus to which the present invention is applied.

FIG. 2 is an explanatory diagram of a main part configuration of the apparatus of FIG.

FIG. 3A is a schematic diagram illustrating the principle of an embodiment of the present invention, and FIG. 3B is an explanatory diagram of a modification thereof.

FIG. 4 is a diagram showing a relationship between the residual potential of a photoconductor and image quality.

FIG. 5 is a schematic configuration explanatory view of another embodiment of the present invention.

FIG. 6 is a schematic configuration explanatory view of another embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a toner adhesion amount on a photoconductor and a transfer residual toner amount.

FIG. 8 is a schematic configuration explanatory diagram of another embodiment of the present invention.

[Explanation of reference numerals] 1 color image reading device (color scanner, 3 originals, 4 illumination lamps, 5 mirror groups, 6 lenses, 7 color sensor, 8 writing optical unit, 9 photoconductor drum (image carrier), 10 photoconductor Cleaning unit, 11 charge eliminating lamp, 12 charger, 13 potential sensor, 14 k developing device, 15 C developing device, 16 M developing device, 17 Y developing device, 18 development density pattern detector, 19 intermediate transfer belt (intermediate transfer belt = Image carrier), 20 belt transfer bias roller, 23-1 paper transfer bias roller, 50a, 50b latent image carrier residual potential detection means, 52 notification means (display section), 656
0a, 60b Toner adhesion amount measuring means, 65 Attached member.

Claims (5)

[Claims] 1. A latent image carrier on which a toner image is formed on a surface by sequentially performing charging, exposure and development, an intermediate transfer member which rotates while contacting with the latent image carrier, and the latent image carrier. First transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at the transfer portion where the intermediate transfer body and the intermediate transfer body are in contact, and second transfer means for transferring the toner image on the intermediate transfer body onto the recording medium. In the image forming apparatus having the transfer means, the latent image carrier residual potential detection means for detecting the potential remaining on the latent image carrier, and the intermediate transfer based on the measurement value of the residual potential detection means. Determination means for determining the life of the body,
An image forming apparatus, comprising: an informing unit for informing the end of life based on the determination result of the determining unit. 2. A latent image carrier on which a toner image is formed by sequential charging, exposure and development, an intermediate transfer member which rotates while contacting the latent image carrier, and the latent image carrier. First transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at the transfer portion where the intermediate transfer body and the intermediate transfer body are in contact, and second transfer means for transferring the toner image on the intermediate transfer body onto the recording medium. In the image forming apparatus having the transfer means, the first detecting means for detecting the potential remaining on the latent image carrier and the second detecting means for detecting the latent image potential formed on the latent image carrier. Determination means for determining the life of the intermediate transfer member based on the detection results of the first detection means and the second detection means, and the end of the life based on the determination result by the determination means. And an informing means for informing Forming apparatus. 3. A latent image carrier on which a toner image is formed by sequential charging, exposure and development, an intermediate transfer member which rotates while contacting the latent image carrier, and the latent image carrier. First transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at the transfer portion where the intermediate transfer body and the intermediate transfer body are in contact, and second transfer means for transferring the toner image on the intermediate transfer body onto the recording medium. And a transfer residual toner adhesion amount detecting means for detecting a residual toner adhesion amount remaining on the latent image carrier after the toner image is transferred onto the intermediate transfer member, and the transfer residual amount. An image comprising: a determination unit that determines the life of the intermediate transfer member based on the detection result of the toner adhesion amount detection unit; and an informing unit that notifies the end of the life based on the determination result of the determination unit. Forming equipment. 4. A latent image carrier on which a toner image is formed by sequential charging, exposure and development, an intermediate transfer member which rotates while contacting the latent image carrier, and the latent image carrier. First transfer means for transferring the toner image on the latent image carrier onto the intermediate transfer body at the transfer portion where the intermediate transfer body and the intermediate transfer body are in contact, and second transfer means for transferring the toner image on the intermediate transfer body onto the recording medium. In the image forming apparatus, the first measuring means for detecting the toner adhesion amount on the latent image carrier before the transfer of the toner image to the intermediate transfer body, and the transfer means for the intermediate transfer body. The transfer rate is calculated by comparing and calculating the second measurement means for measuring the amount of toner remaining on the latent image carrier after the toner image transfer and the measurement values by the first and second measurement means. Judge the life of the intermediate transfer member based on the calculation result of the rate A constant section, the image forming apparatus characterized by comprising a notification means for notifying the service life of arrival based on a determination result of said determining means. 5. A determination unit for determining the life of the intermediate transfer member by detecting a current flowing in a member attached to the first transfer unit and a member attached near each transfer unit of the second transfer unit, and the determination unit. The image forming apparatus according to claim 1, further comprising: an informing unit that notifies the end of life based on the determination result of the unit.