JP2000147961A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which does not cause nonuniform density or wrong color or the like. SOLUTION: By measuring the current value of an intermediate transfer belt 43 from a mark position which is a reference at the time of forming an image, calculating the resistance value of the belt 43, storing it and measuring temperature and humidity at that time, primary and secondary transfer bias voltage in matching with the environmental conditions and the resistance value of the belt 43 can be applied, dispersion among machines, dispersion among the intermediate transfer belts and dispersion in the peripheral length of the intermediate transfer belt are restrained, so that the high-quality image having no nonuniform density is obtained. Furthermore, when deterioration is detected before the specified exchange time of the belt 43, a warning for urging the exchange is immediately displayed, and the number of image forming operation executing times is restored to an initial value in the case of exchanging the belt 43, and the current measuring operation of the belt 43 is performed so as to confirm whether or not the exchanging operation of the belt 43 is executed surely. By continuously displaying the warning on the exchange of the belt 43 on an operation part, unnecessary copyings, low quality image and damages to a machine are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile and the like.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, when a reference mark for superimposing and transferring an image on an intermediate transfer belt as an intermediate transfer image carrier is provided, the mark is used as a reference regardless of the transfer paper size. Thus, an image is formed. For this reason, the frequency of use of the intermediate transfer belt on the downstream side of the standard is low, and the resistance value of the intermediate transfer belt between the upstream side and the downstream side changes over time due to a change in durability, and the original intermediate transfer belt manufacturing process , Resistance unevenness occurred in the entire circumferential direction of the belt. Hereinafter, the intermediate transfer image carrier is referred to as an intermediate transfer belt.

When image formation is performed under the same conditions at different resistance values of the intermediate transfer belt as described above, density unevenness occurs in a single-color image, and in the case of a superimposed image that is a color image, color unevenness occurs in addition to the density unevenness. There were drawbacks, such as differences, that significantly degraded image quality. In the case of forming a color image, it is necessary to make the density fluctuation and color fluctuation of the repeated copy image as uniform as possible.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus free from unevenness in density and color difference.

[0005]

In order to achieve the above object, an image forming apparatus according to the present invention, in an image forming apparatus using an electrophotographic method, performs an intermediate transfer image transfer performed before an image forming operation. Intermediate transfer image carrier current detection means for detecting current of the holding body, and resistance value storage means for storing the resistance value of the intermediate transfer image carrier calculated from the current value detected by the intermediate transfer image carrier current detection means. A transfer bias voltage application unit that applies a transfer bias voltage that matches a resistance value of the intermediate transfer image carrier, and an image forming operation number integrating unit that integrates the number of image forming operations in an image forming operation.
An intermediate transfer image carrier replacement warning unit that warns of replacement of the intermediate transfer image carrier when the current value detected by the intermediate transfer image carrier current detection unit is out of an allowable range.

The image forming apparatus according to a second aspect of the present invention is characterized in that the current detection of the intermediate transfer image carrier is performed at a preset number of operation integrations.

According to a third aspect of the present invention, in the image forming apparatus, when the intermediate transfer image carrier is replaced, the integrated count value of the number of image forming operations is cleared, and the current of the intermediate transfer image carrier is detected. The operation is performed.

According to a fourth aspect of the present invention, in the image forming apparatus, the integrated value of the number of image forming operations is cleared, and the current value detected by the intermediate transfer image carrier current detecting means is out of an allowable range. In the case where it is deviated, a warning that the intermediate transfer image carrier is replaced is displayed continuously.

The image forming apparatus according to a fifth aspect of the present invention is characterized in that a warning of replacement of the intermediate transfer image carrier is displayed on an operation unit.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an image forming apparatus showing one embodiment of the present invention. In FIG.
The laser writing device 41 forms an electrostatic latent image on the photoconductor 42 charged by the charging device 40. This electrostatic latent image is visualized by the developing device 46 and is transferred to the intermediate transfer belt 43 as a toner image carrier. Intermediate transfer belt 43
Is provided with a reference position mark 44 for determining a reference position in the case of multi-color formation. This reference position mark 44
And a density sensor 47 for reading the density of the surface of the photoreceptor 42.

A primary transfer bias roller 51 for transferring images of different colors from the photosensitive member 42 to the intermediate transfer belt 43
Further, a secondary transfer bias roller 53 for transferring the image transferred to the intermediate transfer belt 43 to transfer paper is provided. The intermediate transfer belt current flows to the primary transfer ground roller 52 and is detected by the transfer belt current detection circuit. The image forming apparatus further includes a paper feeding device 48 for feeding paper, a fixing device 49 for fixing a transferred image, and a paper discharging device 50 for discharging paper.

FIG. 2 is a perspective view showing the positional relationship among the intermediate transfer belt 43, the reference position mark 44, and the mark detection sensor 45 in detail.

FIG. 3 is a flowchart showing the flow of the operation of the present invention. In a copying operation, a start button of an operation unit (not shown) is used. In a printer operation, a start signal as a print request from a host (not shown) is used.
The image forming operation in this apparatus starts.

When a start signal is received, it is first determined by a command whether data to be transferred is one color or two or more colors (S).
1). In the case of one color (one color of S1), since there is no need to wait for a mark, transfer of image data is started from a reading unit or a host (not shown). This is written on a photoreceptor 42 by a laser writing device 41 and is transferred onto an intermediate transfer belt 43. At this time, paper feeding is started according to the transferred image front end, and the image is transferred onto the paper. Thereafter, the paper is discharged. After the image formation on the photoreceptor 42 is completed, a specific pattern is written, and the density of the surface of the photoreceptor 42 is read by the density sensor 47. You can know.

In this process, first, writing (S2),
Next, the density pattern is written (S3), the density pattern is read (S4), the paper is fed (S5), the required number of sheets is completed (YES in S6), and the operation ends. If the required number of sheets is not completed (NO in S6), the process returns to before the writing process.

In the case of two or more colors, a reference is required for overlapping each color without deviation. Therefore, the intermediate transfer belt 4
3 and a mark detection sensor 45 for reading the mark, the reference position mark 44
Is detected, and an image is formed based on the detection signal. That is, in the case of two colors, the intermediate transfer belt is rotated twice,
In the case of three colors, three rotations are performed, and in the case of four colors, the rotation is performed four times, and an image is formed based on the mark reference signal. Upon detection of the mark reference signal, transfer of image data is started from a reading unit or a host (not shown).

The laser light is written in the photosensitive member 4 by a laser writing device 41.
2 and transferred onto the intermediate transfer belt 43. By detecting the next mark reference, each color is similarly transferred. When all the colors have been completed, paper feeding is started according to the leading edge of the transferred image, and the image is transferred onto the paper. After this,
Discharge paper. After the image formation on the photoconductor of each color is completed, a specific pattern called a density pattern is written, and the density of the surface of the photoconductor 42 is read by the density sensor 47. You can know whether or not.

This operation will be described with reference to FIG. 3. First, in the case of two or more colors (two or more colors in S1), it is confirmed that the reference position mark 44 on the intermediate transfer belt 43 is ON (YE in S12).
S), a writing process is performed (S13), a density pattern is written (S14), a density pattern is read (S15), and when all colors are completed (S13).
16 (YES), paper is fed (S17), and when all the sheets have been completed (S18), this operation ends.

If the reference position mark is not ON (S1)
(NO in 2) Return to previous operation. If all the colors are not completed (NO in S16), the reference position mark 44 is turned on.
This operation is continued until all colors are completed, returning to the operation before the confirmation of. Further, if all the sheets have not been completed (NO in S18), until all the sheets have been completed,
This operation is continued.

FIG. 4 is a basic operation diagram of the intermediate transfer belt showing the basic operation of the intermediate transfer belt. The relation between the intermediate transfer belt 43 and the reference position mark 44 when the data is one color and when the data is two or more colors. Is shown.

FIG. 5 is a structural diagram showing current detection of the intermediate transfer belt 43. The current detection of the intermediate transfer belt 43 is performed in advance after the power is turned on before the image forming operation is performed, and after the warm-up in which the apparatus can be operated is completed. Intermediate transfer belt 4
When detecting the current No. 3, the primary transfer bias voltage VB determined by the primary transfer bias high voltage power supply is applied in synchronization with the mark reference. The applied primary transfer bias voltage is applied to the primary transfer bias roller 51 and the intermediate transfer belt 4.
3. A current flows through the primary transfer ground roller 52, and the primary transfer bias current IB is detected by the transfer belt current detection circuit.

At the same time, the main control runs the belt counter in synchronization with the mark reference, and initializes the counter when the counter value of the next mark reference one belt revolution NB is reached and clears the counter value NB to zero. When simply calculating the resistance value of the intermediate transfer belt 43 of each device, the current value is read in synchronization with the counter and averaged to obtain IB-ave, and the voltage V
The belt resistance RB-ave is calculated from B. The calculation formula is R
B-ave = VB / IB-ave.

At the same time, the temperature and humidity at that time are detected by a temperature and humidity sensor (not shown), and the primary and secondary values corresponding to the intermediate transfer belt resistance value, temperature, and humidity are previously determined from a nonvolatile RAM or ROM control table in the main control. The next transfer bias voltage is selected, an image forming operation optimal for the current environment and the state of the intermediate transfer belt is performed, and the resistance value, temperature, and humidity of the intermediate transfer belt are stored in a nonvolatile RAM or the like.

If the intermediate transfer belt current detecting operation is performed every time after the power of the apparatus is turned on, the waiting time for the operator is increased, and the temporal change of the intermediate transfer belt 43 is reduced by 50%.
Since the number of image forming operations becomes about 0 and it takes a long time, the number of image forming operations is integrated, and when the required number of times is reached, the intermediate transfer belt current detection is performed.

Further, when the intermediate transfer belt current detecting operation is performed at a predetermined time, before the intermediate transfer belt 43 reaches a predetermined replacement time, the intermediate transfer belt resistance value as a result of the current detecting operation is out of an allowable range. If it is removed, the operator is prompted to display and warn to replace the intermediate transfer belt. Further, when the operator or the maintenance manager replaces the intermediate transfer belt 43, the accumulated number of image forming operations is cleared to zero which is an initial value, and the current detection operation in the initial state is performed. In this state, if the detection result is still out of the allowable range, it is continuously displayed as an operation error of the operator or the maintenance manager, a warning is issued, and replacement of the intermediate transfer belt 43 is prompted.

FIG. 6 shows an embodiment of a transfer belt current detecting circuit for detecting the current of the intermediate transfer belt 43, and the current is detected by this circuit.

[0027]

According to the present invention, the current value of the intermediate transfer belt from the mark position serving as a reference at the time of image formation is measured, the resistance value of the intermediate transfer belt is calculated and stored, and the temperature and humidity at that time are measured. The primary and secondary transfer bias voltages that match the conditions and the resistance value of the intermediate transfer belt can be applied to reduce variations between machines, variations between intermediate transfer belts, variations in the circumference of the intermediate transfer belt, and density. A high-quality image without unevenness can be obtained. Further, when the deterioration is detected before the predetermined replacement time of the intermediate transfer belt, a warning prompting the replacement can be displayed immediately.

When the intermediate transfer belt is replaced, the number of image forming operations is returned to the initial value, and the current measurement operation of the intermediate transfer belt is performed, thereby confirming whether or not the replacement operation of the intermediate transfer belt has been reliably performed. It can be carried out.

By continuously displaying the warning of the exchange of the intermediate transfer belt, even if the operator or the operator intentionally performs an erroneous operation or an erroneous operation, unnecessary copying and copying can be performed.
A low-quality image and a device that does not damage the machine can be provided. By displaying this warning on the operation unit, the warning can always be displayed continuously.

[Brief description of the drawings]

FIG. 1 is a structural diagram showing an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a partially enlarged view of the structure of the image forming apparatus shown in FIG. 1;

FIG. 3 is a flowchart illustrating a flow of an operation of the image forming apparatus illustrated in FIG. 1;

FIG. 4 is a basic operation diagram of the intermediate transfer belt showing a basic operation of the intermediate transfer belt shown in FIG. 1;

FIG. 5 is a structural diagram showing current detection of the intermediate transfer belt shown in FIG.

6 is a current detection circuit diagram showing current detection of the intermediate transfer belt shown in FIG.

[Explanation of symbols]

 Reference Signs List 40 charging device 41 laser writing device 42 photoreceptor 43 intermediate transfer belt 44 reference position mark 45 mark detection sensor 46 developing device 47 density sensor 48 paper feeding device 49 fixing device 50 paper discharging device 51 primary transfer bias roller 52 primary transfer ground Roller 53 Secondary transfer bias roller

Claims (5)

[Claims] 1. An image forming apparatus using an electrophotographic method, wherein an intermediate transfer image carrier current detecting means for detecting a current of the intermediate transfer image carrier performed before an image forming operation; Resistance value storage means for storing the resistance value of the intermediate transfer image carrier calculated from the current value detected by the detection means; transfer bias voltage application means for applying a transfer bias voltage matching the resistance value of the intermediate transfer image carrier An image forming operation number integrating means for integrating the number of image forming operations in the image forming operation; and the intermediate transfer image carrier when a current value detected by the intermediate transfer image carrier current detecting means is out of an allowable range. And an intermediate transfer image carrier replacement warning unit that warns replacement of the image. 2. The image forming apparatus according to claim 1, wherein current detection of the intermediate transfer image carrier is performed at a preset number of operation integrations. 3. When exchanging the intermediate transfer image carrier, the integrated count value of the number of image forming operations is cleared.
2. The image forming apparatus according to claim 1, wherein a current detection operation of the intermediate transfer image carrier is performed. 4. The image forming apparatus according to claim 1, wherein the accumulated number of image forming operations is cleared and the current value detected by the intermediate transfer image carrier current detecting means is out of an allowable range. 2. The image forming apparatus according to claim 1, wherein a warning of body replacement is continuously displayed. 5. The image forming apparatus according to claim 1, wherein a warning of replacement of the intermediate transfer image carrier is displayed on an operation unit.