JPS6275654A - Developing method - Google Patents

Abstract

PURPOSE:To perform superior development without photographic fog by sticking positively a developer, which is electrostatically charged with a polarity to a non-image area of a latent image carrier in a developing part. CONSTITUTION:In a developing part 8, an AC voltage having 1,800Hz frequency and 1,400V inter-peak voltage and a developing bias DC voltage are applied between a drum 1 and a sleeve 6. The developing bias is set to -600V in the non-image area and is switched between an image area and the non-image area by control means 11. The surface of the drum has about -200V, and the developer is easily stuck to the drum f from the sleeve 6 because +400V DC potential difference exists on a basis of the sleeve 6. Thus, an inverted toner is stuck to the drum 1 and is removed from the sleeve. A magnetic toner 5 stuck to the drum is removed by a cleaning member 15. Since the inverted toner is positively removed from the sleeve 6 to the non-image area, positive photographic fog and reversal photographic fog due to the flocculated inverted toner are prevented in the early stage during the normal copying operation and the development characteristic in the initial stage is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a developing method for a recording device such as a copying device or a printing device.

[Prior art to the invention]

Conventionally, in recording apparatuses, many component developers have been used, which enable miniaturization and cost reduction of the apparatus.

However, the component developer (hereinafter referred to as toner) has a large amount of toner charged with a polarity opposite to the normal polarity (hereinafter referred to as reverse toner), especially in the initial period after toner replenishment.
This occurs most of the time when the toner is used, and white JI! occurs on the recording paper after recording. ! 11 spots appear in some areas (hereinafter referred to as inversion fog).・Even more white #! , a problem occurs in which parts of the body become blackish (hereinafter referred to as iE fog), and the gradation is... [Object 1 of the invention] The present invention has been made in view of the problem described in 1-1, and it provides a development method that is useful for developing properties without fogging. The goal is to provide the following.

[Summary of Development 1-1] The present invention is a developing method for achieving the 11th objective described in (11), in which, in the developing section, 11 ['I have a polarity opposite to the small polarity;
This method is characterized in that the electrically charged developer is actively attached to the non-image area of the latent image carrier.

[Example of Part II]

The applicant estimated the above problem as follows.

During toner cartridge filling and photoconductor cap process-f
- When new toner is supplied, such as when a process cartridge having at least one stage is loaded, the toner density is high and agglomerated toner is likely to occur. If the aggregated toner is charged to the opposite polarity, if there are many opportunities for friction with the toner carrier, the polarity will become suitable for development, but the friction with the toner carrier, which is the first stage where the tripo is q- is difficult to obtain, and the toner remains as a reverse toner. Furthermore, it is thought that the aggregated reversed toner coughs up a plurality of toners of opposite polarity, which may cause new aggregation to occur, leading to a vicious cycle in which the reversed toner is likely to be formed again.

Furthermore, if aggregated toner exists on the surface of the toner carrier, it is considered that the friction of small single toner particles with the surface of the toner carrier becomes a major hindrance, making it impossible to obtain a 1-minute tripo, resulting in the occurrence of positive fogging. Generally, magnetic toner to which magnetism is applied is often used as one-component toner. In this case, in particular, if the above-mentioned reversed toner exists, it will be bound by the magnetic field generated by the magnetic poles inside the toner carrier and will be easily attracted to the surface of the toner carrier (a non-magnetic sleeve is used for the crotch). Therefore, it is thought that fogging is likely to occur from the initial stage.

Hereinafter, an embodiment of the single-shot IJI will be described with reference to the drawings.

FIG. 1 is a sectional view of a copying apparatus to which a developing method according to an embodiment of the present invention is applied.

In the figure, 1 is a photosensitive drum (hereinafter referred to as a drum) which is a latent image carrier. , the optical information passing through the lens array 3 is irradiated onto the surface of the drum 1 to form an electrostatic latent image.

The developer container 4 has a magnetic toner 5 therein and a developer sleeve 6 (hereinafter referred to as "sleeve") that supports the magnetic toner 5. The sleeve 6 is located at a narrow distance of about 300 mm from the drum 1, rotates in the same direction as the drum in the developing section 8, and surrounds the magnetic roller 4 having a developing magnetic pole therein.

The surface of the sleeve 6 is regulated by a magnetic plate 7, and is approximately 70. A thick layer of toner is carried.

In the developing section 8, a voltage is applied between the drum 1 and the sleeve 6 via a voltage application stage 9, and the magnetic toner carried on the sleeve 6 adheres to the drum 1 and is developed.

The recording paper 13 is fed by the registration roller 12 in synchronization with the drum l, and the developed image is transferred onto the recording paper 13 by the transfer charger 14 to which a voltage is applied by the voltage application stage 16. is a constant 7 not shown.
It is fixed by 7 members. After the transfer, the magnetic toner remaining on the drum 11- is removed by the cleaning member 15. Timing is controlled here.

An alternating voltage with a frequency fi of 1800 Hz and a peak open voltage of 1400 V and a developing bias DC voltage are applied between the drum 1 and the sleeve 6.

Here, in development i'1118, in one image area, the dark area voltage is -700V and the bright area voltage is -200V.
A latent image of V is formed, and the latent image is developed by the alternating voltage and direct current voltage applied to the sleeve 7.

At this time, the DC voltage is -250V, which generates a potential difference of 50V-100V with the opposite polarity to -200V in the bright area of the latent image.
V~-300V is applied.

Here, if the magnetic toner has obtained a 1-min tripo from the sleeve, it has the opposite polarity to the bright part of the latent image, that is, it has the same polarity as the toner.
T! , because of the potential difference, magnetic toner does not adhere and positive overflow does not occur.

However, if reversal toner exists in the magnetic toner used for development, it will adhere to the first portion of the latent image IJ, causing reversal fog.

That is, considering the above estimation, the aggregated toner on the toner carrier 1 is likely to become reverse toner, and it is necessary to remove it.

Since there are such reports, we have adopted the ones detailed below.

First, using FIG. 2, the characteristics of magnetic toner elucidated by the applicant will be explained.

The solid line in FIG. 2 shows the sleeve 6 on the surface of the drum 1 when the alternating voltage is applied. (This shows the relationship between the DC potential difference and the magnetic toner 111 attached to the tram l.

0■ in the center of the graph indicates that the drum surface and the sleeve 6 are at the same potential.To the right of 0■ is the ease with which the latent image is developed, and to the left of Ov is the image IJJ? This shows how easily the reversal toner adheres to the surface.

It can be seen from this figure that the amount of reversed toner adhering to the drum 1 begins to increase at approximately 350 V or higher.

Next, the developing method of the present invention will be explained.

Figure 3 shows an example of the developing bias direct current voltage applied to the sleeve and the timing of application.
I'l: i minute -600V (1) developing bias is applied. This control of switching between the image area and the non-image area of the DC voltage is performed by the control-1 stage 11. The latent image on the surface of the drum 1 has been erased to suppress excess toner consumption, and the entire surface has a voltage of about -200V. There is a DC potential difference of approximately +400V on the surface of the drum 1 with respect to the sleeve 6, and as shown in Figure 2, +400V (>+35
0V), it becomes easier for the toner to land on the tram l from the sleeve 6. Therefore, the reversed toner adheres to the drum 1 and is removed from the sleeve 6. At this point, the magnetic toner adhering to the drum l is removed by the cleaning member 15. Ru.

At this point, no image is to be formed, so the control "stage 1"
1, turn off the device 14, apply magnetic toner to the surface of the roller L, and apply the reversed toner to the cleaning member 15 while keeping it 71.

According to this method, since the reversed toner in the non-image area is removed from the sleeve 6 periodically, the reversed toner that has aggregated is likely to cause a problem, and the reversed toner that has accumulated in the fi During normal copying operations, the initial development characteristics were reduced due to the reduction of the agglomerated inversion toner, which was prevented during normal copying operations due to the formation of inversion toner. 4
It is also possible to plan a corridor.

In experimental examples, in the conventional developing method, normal fogging and reverse fogging occurred initially after loading the process cartridge until about 300 sheets were printed.

On the other hand, when using the developing method as in this example,
After about 20 sheets, normal fogging and reverse fogging stopped occurring. That is, it can be seen that the development method for undeveloped IJ significantly reduces the occurrence of normal fog and reverse fog.

Next, another embodiment of the unreleased IC will be described with reference to FIGS. 4 and 1.

Similar to the above embodiment, a frequency of 1800 Hz and a voltage of 1400 V (7) between the beakers 4 and a developing bias DC voltage are applied between the drum 1 and the sleeve 6, and a dark area voltage of -700 V is applied to the surface of the drum 1 during one image. , bright area voltage -
A latent image of 200 volts is formed, and a DC voltage of 1250 volts is applied to develop the image.

Here, as shown in FIG. 4, the No. 1 image area is corona released! , I1 depending on the vessel? Turn off the power and bring the upper surface of the drum 1 to almost zero.

This causes the reversal toner to be applied to the non-image area of the drum.
In order to maintain the DC potential difference of +400V in order to make the voltage i), the DC voltage applied in Example 11-600 is kept at -400V.

Control of turning on/off of the charger and switching of the DC' voltage is performed by a control stage 11.

By using this method υ, it is possible to reduce power consumption and use Ichihara, which has a low breakdown voltage and is inexpensive.

In Example 1-, the reversed toner attached to the drum surface passed through the transfer charger and was guided to the cleaning member. A separate cleaning member may be provided between the electrodes to remove the reversed toner.

Furthermore, during image formation 1iJ drum rotation, in which light is irradiated onto the drum surface to stabilize the image, and/or during drum rotation after image formation, in which light is irradiated to avoid leaving any charge history on the drum surface. In order to deposit the reverse toner when no image is formed, it is preferable to control the developing bias DC voltage and the corona discharger in the cylinder.

Note that the present invention is not limited to this embodiment, and any developing method may be used as long as the reversal toner is positively attached to the non-image area by applying a different voltage or by using magnetic force. The area to which the adhesive can be applied is not limited to the entire non-image area, but may also be a part of the area.

〔Effect of the invention〕

As explained above, by using the present invention, not only the development characteristics can be improved from the beginning, but also reverse fog and normal fog can be largely eliminated in the post-process period, and the effect is great.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copying apparatus to which the developing method of the present invention can be applied, and FIG. 2 is an explanatory diagram showing the DC potential difference between the drum and the sleeve and the amount of toner attached. FIG. 3 is an explanatory diagram II showing the timing of application of DC voltage according to an embodiment of the present invention, and FIG. 4 is an explanatory diagram showing the timing of application of DC voltage and charging by a corona discharger according to an embodiment of the present invention. be.

Claims (1)

[Claims] A developing method characterized in that, in a developing section, a developer charged with the same polarity as an electrostatic image to be developed is actively attached to a non-image area of a latent image carrier when an image is not being formed.