JPS5913250A - Image formation method - Google Patents

Abstract

PURPOSE:To form a test pattern which is not influenced by the brightness of a lamp, etc., by transferring toner to a photosensitive drum after destaticization from a developing roll applied with a bias having the same polarity with the toner. CONSTITUTION:The developing bias 28 having a higher potential than the texture of a photosensitive drum surface 1 is applied to the developing roll 17 during copying operation. When the test pattern is formed, the toner is transferred from the developing roll 17 applied with the bias 29 having the same polarity with the toner to the photosensitive surface after destaticization by an erasure lamp 4. This toner image is transferred to a sheet 19 to obtain the test pattern, checking the developing ability of a developer. Then, the brightness of the erasure lamp 4 is increased enough and the constant bias 29 is used, so that the density of the test pattern reflects on only the developer ability regardless of the illuminance of an exposure lamp, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming method in which it is possible to easily check the developing ability of a developer.

As is well known, in electrophotographic equipment,
An electrostatic latent image formed on a J:5 image carrier such as a photoconductor or dielectric is developed by colored fine particles called toner.
The image is played. It is well known that the density of the reproduced toner image depends on many factors.
ing. The density of a toner i+ui image typically depends on the toner concentration in the developer. The developer that is normally used in this device is called a two-component developer, and consists of two components: toner and carrier.
Its role is to abrasively charge the toner to a predetermined polarity, adsorb any stiffness, and carry it to the development position. In the scooped image position 1, only the toner is attracted to the static latent image, and the electrostatic latent image is removed. For this reason, due to repeated development, the toner concentration in the developer decreases, and if the density decreases or develops with 11 developer, the developed toner will naturally have a low vA value. becomes. Therefore, this 5 bicomponent yarn I1. In the image forming method using fM'Gariga, a toner density sensor is used,
To keep the mound capacity constant, the toner concentration with respect to the developer is managed and controlled.

However, for example, if the detection function of the toner concentration detection unit itself becomes abnormal, the toner concentration control will be correct.
Line 1j disappears. Whether such toner density control is being performed normally or not can be determined to a certain extent by those skilled in the printing process, but it is important to note that the print image density is 1. In addition to toner density,
It changes depending on the charging potential, the amount of exposure, etc., and it is difficult to determine which process system is causing the abnormality in the print quality.

The present invention has been made in view of the above-mentioned problems, and is an image forming apparatus which can obtain a rectangular pattern on a transfer paper and check for abnormalities in the image forming process. 1
The purpose is to lower the droplet formation power method by 1.

This invention will be explained below with reference to figures 111 and 116.

FIG. 11 shows an example of an electrophotographic apparatus to which the method for forming both edges according to the present invention is applied. A charging charger 2, an exposure optical system 3, an erase lamp 4, a developing device 5, a light emitting element 6 for detecting toner adhesion, and a light receiving element are arranged around the photosensitive drum 10 along the counterclockwise rotation direction thereof. Element 7, transfer charger 8, fixing device f! 1'9, a static elimination charger 1 (1, a static elimination lamp JJ, a cleaning device 12, etc.) are arranged.The surface of the photoreceptor drum is first uniformly charged to a predetermined polarity by the charging charger 2. Then, the light image of the original to be copied is irradiated thereon through the exposure optical system 3, and the electrical charge on the photoreceptor is selectively erased, leaving a latent image thereon in the still image corresponding to the original image. is formed.This electrostatic latent 1 diaphragm is supplied with toner from the 96 image device 5.The developing device t5 supplies a two-component developer 1ψ agent 13 consisting of toner and a magnetic carrier. In the process of stirring by the impeller 5 and pumping up by the pumping roller 16, the toner is charged to a polarity opposite to that of the electrostatic latent image due to friction with the carrier. After the toner is transferred from the roller 6 to the developing roller 17, only the toner is adsorbed to the electrostatic image at a level close to the photoreceptor, and development is performed.i,r
If 5.0 The toner on the image roller 17 is scraped off from the top of the developing roller 17 by the scraper 18. The toner image (-1,
During a normal copying cycle, paper feed cassette 19 and paper feed roller 20. A band is superimposed on the transfer paper 23 fed by the conveyance rollers 21 and 22, and has a polarity opposite to that of the toner charged by the transfer charger 8. By receiving the image, the image is transferred onto the transfer paper 23. After the transfer, the transfer paper 23 which has been folded over the surface of the photoreceptor 161 by a minute M[t] enters the fixing device 9, receives the electric layer of the transferred toner image, and is ejected onto the tray 24. On the other hand, the photoreceptor after the transfer is subjected to the removal of residual charges by the charge eliminating charger 10 and the charge eliminating lamp 11, and the removal of residual toner by the cleaning device]2.

rif child photo ↓-↓ in the device! When image density control is to be performed, the timing generation circuit 25 turns on the intensity detection circuit 26 and switches the switch 27 to the point 27b1111I. 270 is connected to the drawing point 27a side () (Iasumi source 28 crab), and during the normal copying cycle,
A bias potential is applied to the developing roller 17, which also serves as an image electrode, at a level slightly higher than the background potential on the photoconductor 1, and having the same polarity as this, that is, a polarity different from that of the toner charging. This prevents background development on the photoreceptor and prevents background smudges on copies.

On the other hand, to the contact 27b side of the switch 27, a bias power supply 29 is connected which has a polarity opposite to that of the bias power supply 28, that is, a toner power of 1j7 and a polarity of the toner power of 1j7.

In the present invention, the surface potential of the photoreceptor l is brought close to the saturated residual potential, preferably close to zero V (=J), and the image potential is obtained by increasing the bias potential. In the embodiment, it is important to bring the photoconductor voltage close to zero V.

This is done by illuminating 40 erase lamps.

The surface potential of the photoreceptor becomes almost zero due to the light irradiation of the erase lamp, and this is the most stable electric potential that is not easily affected by variations in charging potential or light intensity.

In this way, when the position of the elbow and body is at zero OV, and a bias potential of the same polarity as that of the toner is applied to the second image roller 17 from the power supply 29, the paddy grains are , statue container】4
The toner on the inner roller J and the roller 17 adheres to the surface of the photoreceptor due to the force of the electric field. The bias potential at this time is -I00V or higher when the toner is in a negative position.
Only 2V or 2V is sufficient, but a range between -200 and -400V is effective. As for the kneading, it's up to them.

Here, the %R of the present invention is the above μm1<
At the same time, the sticking toner area on the surface of the photoreceptor is transferred to a transfer paper to obtain a test pattern. As shown in the figure, the toner sensor consisting of a pair of light-emitting elements 6 and light-receiving elements 7 is uniformly disposed on the photoreceptor. $ pattern t based on the reflectance determined above
++a brightness, bright image formation, the development phase of this pattern and the density of the toner image are detected, and based on the results 1', the replenishment of toner to the developer is controlled.

Now, in this method, the toner density is changed in response to a change in υ of 5 m 1 w 1 degree due to deterioration of the developer itself, changes in developing ability due to JR boundaries, changes in charging potential, changes in illumination light amount, etc. This is a more dynamic method of keeping the image constant.

However, for example, uneven charging occurs between the reference pattern portion on the photoreceptor to which the detection light from the light emitting element 6 is to be applied once and other portions. In this case, it is possible that the toner concentration is over-corrected. For example, if the aspect that causes uneven charging is that the potential is low in the reference pattern part, the amount of adhering toner in this part will decrease, so the correction f-control should be applied to make the toner density redder. It's put away. When such a point reaches the end, the toner concentration becomes abnormally low, and depending on the situation, the inside of the container may be contaminated with toner.

However, it is not possible to determine whether this abnormality in the toner charge is due to uneven charging, an abnormality in the light, or the current state of the art. In view of this, in the present invention, only the functional horn of the desk 1 is checked. When the residual potential is set, 1 is applied to the surface of the light body! By applying a bias potential to the image roller J7, the toner on the i++' and yup rollers is caused to adhere, the +J toner small area on the photoconductor is transferred to a transfer paper, and the image is settled, A test pattern is obtained on this transfer paper, and by visually comparing this test pattern with a reference density image prepared in advance, the development process including factors such as toner density and developer life is determined. It is possible to check for abnormalities in performance and toner concentration sensor. This is because, according to this method, there is no influence on factors such as charging unevenness outside the mW capacity and heat-light abnormalities. In addition, with the above test pattern binding (J, both images on the halftone or black solid formed on the copy, 1
For example, by setting the Sugi J1 image bias to -200 to -400V, the halftone test pattern can be
I can do that.

By the way, assuming that the copy image at that point in time is abnormal, a test pattern is obtained by the above method, and the lI! of this test pattern is obtained. II If the image density is abnormal, first check the developing ability, and if no abnormality is found in this check, 4411 +ivr will be performed to determine that the cause of the abnormality is other than the developing ability, and this will be dealt with. Check the charging system and exposure system. In this way, in the method of the present invention, it is possible to check for factors other than current performance, and by eliminating each factor, it is also possible to check for abnormalities caused by changes in the sensitivity of the photoconductor or custom-made photoreceptors, for example. I can do it. In the present invention, the method has been described in which the amount of toner applied on the photoreceptor is detected and the toner concentration is controlled by ff+lJ, but in addition to this, the fluidized group of the developer can be detected by the change in magnetic permeability. Depending on the number of copies, toner sleeve (constant or soft replenishment method as in the sixth example), or color tone sensor method that detects developer reflected light. can.

As described above, according to the present invention, it is possible to provide an image forming method that can easily check abnormalities in block method systems and other image forming process systems.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an example of an electrophotographic apparatus to which the image forming method according to the present invention is applied. ■...Photoreceptor as image carrier, 17...Developing roller as developing electrode

Claims (1)

[Claims] 1. An image forming method including developing an electrostatic latent image formed on an image carrier with toner on a developing electrode. bringing the surface potential of the front RL image carrier close to a saturated residual potential; applying a predetermined voltage to the developing electrode to cause the toner to adhere to the surface of the image carrier; and increasing the temperature on the surface of the image carrier. An image forming method comprising transferring a toner area portion to a transfer paper to obtain a test pattern on the transfer paper. 2. f+: The image forming method according to claim 1, wherein the polarity of the voltage applied to the first electrode is the same as the charging electrode phase of the toner. 3. The previous 6α coordination residual potential of 15 is zero V/h￥
The image forming method according to item 1.