JPS63172289A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the quality of a reproduced picture in thin liens or the edge parts of an image by forming a relative speed between a developer on a developer carrier and a latent image holder. CONSTITUTION:A pulse motor 55 rotationally drives a developing roll 34 at a speed to be varied at a fixed thin period, a speed on the outer periphery of the roll 34 is varied within the speed range of + or -about 20% a speed on the outer periphery of a photosensitive drum 22 and the average speed is controlled so as to be equal to the speed on the outer periphery of the drum 22. When a relative speed is zero, the developer on a part opposed to an image on the roll 34 is reduced and the adhesion of the developer to the edge part of the image is reduced or dropped. However, a relative speed is vertically formed between the outer periphery of the drum 22 and the roll 34 at a thin period. Thereby, thin lines or the edges of an image can be developed with high reproducibility.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to image forming apparatuses such as copying machines and printers that apply electrophotography.

BACKGROUND OF THE INVENTION Conventionally, developing methods using dry developers can be roughly divided into two types: methods using two-component developers and methods using one-component developers.

The method using a two-component developer uses a mixed developer of toner and carrier, so it requires a toner concentration control device to maintain a constant mixing ratio of toner and carrier, and has disadvantages such as periodic replacement due to carrier deterioration. I have. Therefore, recently, in order to eliminate the drawbacks described on the previous three pages, a developing method using only a one-component developer without using a carrier has been proposed.

This developing method is disclosed in, for example, Japanese Unexamined Patent Publication No. 54-43027, and its configuration is shown in FIG.

In FIG. 9, 1 is a developing roller, 2 is a magnetic component toner, 3 is a hopper, 4 is a blade, and 5 is a photoreceptor. The developing roller 1 is made of a metal material with an uneven surface, and has a magnet inside thereof, and the toner 2 is supplied from the hopper 3 by the magnetic force of the magnet. Next, when the developing roller 1 rotates in the direction of the arrow, the toner 2 is charged to a predetermined polarity by the blade 4 in sliding contact with the surface of the developing roller 1 and coated on the surface of the developing roller 1. Next, the charged toner 2 moves at the same speed as the electrostatic latent image on the photoreceptor 5 at the development position and is attached to the image area on the photoreceptor side for development.

Problems to be Solved by the Invention However, in this type of system, the toner is blown into the air by the electric field formed in the space between the electrostatic latent image of the photosensitive member and the developing roller. It is difficult to apply toner faithfully to the image, resulting in fine lines in the image and dull edges. This phenomenon becomes more pronounced as the distance between the photoreceptor and the developing roller increases. That is, in order to faithfully reproduce an image, it is necessary to reduce the distance between the photoreceptor and the developing roller, but in this case, the configuration of the device including the photoreceptor and the developing roller requires extremely high precision. Moreover, toner and the like tend to get clogged in that space. On the other hand, if the distance is increased in order to increase the accuracy margin, there is a drawback that the reproduced image quality is inferior.

The present invention solves these conventional problems and provides an image forming apparatus with high image quality.

Means for solving the problems and technical means of the present invention for solving the above problems include a latent image holder having an electrostatic image, and a developing device provided opposite to the latent image holder. a developer carrier, and a thin layer forming means for forming a thin layer of developer on the developer carrier, and the surface of the latent image carrier and the developer on the developer carrier are formed at a development position. A driving means is controlled such that a constant distance is provided between the five pages and a relative speed is generated during development between the surface of the latent image holding member and the developer on the developer carrying member at the developing position. It was established.

action The effect of this technical means is as follows.

That is, in a developing method in which a thin layer of developer is formed on a developer carrier, and the developer is caused to fly onto a latent image carrier prepared at a certain distance from the thin layer, development is performed. By providing a relative speed between the developer on the developer carrier and the latent image carrier, the reproduction quality of fine lines and edge portions of the image is improved.

Example Examples of the present invention will be described below.

1 to 5 show a first embodiment of the present invention, which is an example of use in a laser beam printer.

In FIG. 1, reference numeral 22 denotes a latent image holder, which is a photosensitive drum 6 having a photoconductor 24 such as zinc oxide, selenium, or an organic photoconductive material supported on the surface of an aluminum base 23. (Thus, the latent image holder 22 is hereinafter referred to as the photosensitive drum 22.) Reference numeral 54 is a motor that rotationally drives the latent image holder 22, and the outer circumference of the latent image holder 22 is rotated at a constant speed in the direction of the arrow shown in FIG. controlled to move. 2
Reference numeral 5 denotes a charger which applies a negative corona in the case of zinc oxide and a positive corona in the case of selenium, depending on the photoconductor 24 on the photosensitive drum 22, using a first DC high-voltage power supply 26 to cover the entire surface of the photoconductor 24. It charges the battery with electricity. Reference numeral 27 denotes an optical section that projects light modulated by a laser according to a signal onto the photosensitive drum 22 to form an electrostatic latent image. 28 is a developer which is a normal non-magnetic component insulating toner.

Reference numeral 29 denotes a housing having an outlet portion 30 at one end and a replenishment opening 31 at the other end, and housing the developer 28. 32 is a lid of the replenishment opening 31 of the kyoukyu 29. 33 is a sheet-like elastic member made of, for example, a sheet-like polyethylene terephthalate with a thickness of about 40 μm, one end of which is M3.
It is fixed to one side 32a of 2. A developing roller 34 is a developer carrier (hereinafter referred to as developer carrier 3).
4 is referred to as a developing roller 34. ) Page 7 For example, metal rollers made of stainless steel, aluminum, etc.
A metal roller whose surface is coated with resin or the like is used, preferably a developing roller 3 as shown in FIG.
The outer peripheral surfaces 34a and 34b at both ends of 4 are smooth surfaces, and the central surface 3
A rough surface with fine irregularities is formed on 4e. Further, the developing roller 34 is located at the exit portion 30 and is installed at a constant distance from the photosensitive drum 22. Reference numeral 55 denotes a pulse motor that rotates the developing roller at a speed that fluctuates at a constant fine period. In this embodiment, the speed of the outer circumferential surface of the developing roller is approximately 20 plus or minus the speed of the outer circumferential surface of the latent image holder. The speed is controlled such that the speed varies within a range of 100% and the average speed is the same as the speed of the outer peripheral surface of the latent image carrier. That is, the outer circumferential surface of the developing roller performs development while maintaining a relative speed in the vertical direction periodically with respect to the outer circumferential surface of the latent image holder. In this embodiment, the developing roller 34 is driven by a pulse motor, but the same effect can be obtained by controlling a normal DC servo motor to periodically change its speed instead of the pulse motor. Note that the photosensitive drum 29 is electrically insulated from the photosensitive drum 22 and the developing roller 34. Reference numeral 35 is a fur brush that is a cylindrical elastic body, a roller made of sponge, etc., and a layer of elastic material 37 is formed on the outer peripheral surface of the core metal 36. In this embodiment, the cylindrical elastic body 35 is a fur brush (therefore,
In this embodiment, the cylindrical elastic body 35 will be referred to as a fur brush 35 hereinafter. ) The elastic material 37 is made of conductive fur using carbon-containing rayon fiber. Further, the fur brush 35 is located within the developer 28 of the present day 29 and is in sliding contact with the surface of the developing roller 34, and is rotated, for example, clockwise and at a circumferential speed of the developing roller 34 or higher to prevent spillage of the developer 28. . Furthermore, the fibers of the fur brush 35 have a spiral shape in the direction in which the developer 28 moves from the outer periphery of both ends of the fur brush 35 to the center when it rotates, as shown in FIG. 38 is a scraping plate that comes into sliding contact with the fur brush 35.
This is to make the amount of developer 28 in the container uniform. Further, in this embodiment, the scraping plate 38 is made of a conductive material, and is also used as a detection plate by connecting the detection means 43. In this case, it goes without saying that the scraping plate 38 and the cutout 29 are electrically insulated. In this way, by sharing the scraping plate and the detection plate, the configuration of the device can be further simplified. FIG. 2(d) is a diagram showing the detection means 43, and is a diagram illustrating the detection means 43.
The current when connected to the developing roller 34 through a resistor R of approximately OKΩ is detected by an ammeter M. Furthermore, the fur brush 35 agitates the developer 28 and performs frictional charging due to friction between the fur brush 35 and the developer 28, and also comes into close or sliding contact with the surface of the developer 29 and comes into sliding contact with the scraping plate 38 to develop the material. This is to help triboelectrically charge the agent 28.

Further, the peripheral speed of the fur brush 35 is faster than the peripheral speed of the developing roller 34. Therefore, the developer 28 adhering to the surface of the developing roller 34 can be scraped off after the developing process. 39 is a partition plate that prevents uncharged developer 28 from reaching the vicinity of the developing roller 34 and fur brush 35;
Furthermore, it is intended to prevent the developer 28 from stagnation.

Reference numeral 40 shown in FIG. 3 is a bearing for the developing roller 34, and reference numeral 41 is a bearing for the fur brush 35. On page 4810, a bias during development is formed by a DC high-voltage power supply applied between the photoreceptor 22 and the developing roller 34, and in this embodiment, a DC voltage of approximately the same potential as the charged potential of the photoreceptor is applied to the developing roller. Perform reversal development. Reference numeral 42 denotes a second DC high-voltage power supply which is a voltage applying means, and during development, the circuit is opened and no voltage is applied between the developing roller 34 and the fur brush 35, and the charged developing image is generated only during the period when no developing is performed. A DC voltage having a polarity opposite to that of the developer is applied between the developing roller 34 and the fur brush 35. A blade 44 is a layer thickness regulating means for regulating the layer thickness of the developer 28. In this embodiment, a rubber blade made of an elastic material such as urethane rubber is used. It may be made of an elastic synthetic resin such as polyethylene terephthalate, an elastic metal such as phosphor bronze or spring steel, or an elastic metal or synthetic resin coated with a fluororesin. Further, the blade 44 is located downstream of the two parts of the developer 28 parts with respect to the rotational direction of the developing roller 34 and upstream of the portion facing the photosensitive drum 22 of the developing roller 34 .
It is provided in pressure contact 11<- to the surface of. Further, the width of the blade 44 is equal to the outer peripheral surface 34a at both ends of the developing roller 34, as shown in FIG.

The length is such that it makes contact with 34b. 45 and 46 are developer sealing materials for preventing the developer 28 from leaking, and are made of an elastic material such as felt, sponge, or bum. Further, the developer sealing materials 45 and 46 are in contact with the outer circumferential surfaces 34a and 34b at both ends of the developing roller 34 and both end surfaces of the blade 44. Since the fur brush 35 is made of a conductive material, the amount of charge on the developer 28 will vary due to slight differences in each part of the fur brush 35 during frictional charging. It has the function of neutralizing the electric potential and making the potential uniform. Therefore, it is preferable to use a conductive material for the fur brush 35 having a specific resistance of about 1010 ΩCm or less, preferably 10 3 Ωem to 10 7 Ωem. The fur brush 35 may be made of not only conductive rayon fiber as in this embodiment, but also other conductive fibers, or a fur brush made by electrostatic flocking to make the coating uniform. It is also effective to use Furthermore, a cylindrical elastic body 3
Even if a conductive sponge, conductive cloth, or soft wire brush is used as the elastic material 37 in No. 5, the frictional charging and
Of course, effects such as coating can be effectively performed. Note that when the developer 28 is a one-component magnetic toner, it is also effective to use a magnetic roller as the mandrel 36 and form a magnetic brush on its outer periphery to form the cylindrical elastic body 35. The developer 28 in the housing is supplied at least downstream from the opposing position of the developing roller 34 and the blade 44 and upstream from the opposing position of the developing roller 34 and the fur brush 35 with respect to the moving direction of the developing roller 34. It is configured so that it does not occur.

Reference numeral 52 denotes a developer leak prevention sheet, which is made of an elastic material such as polyethylene terephthalate or urethane rubber and has a thickness of 100 μm or less.
4, and its tip is attached so as not to protrude downstream from a line connecting the centers of the developing roller 34 and the fur brush 35. Further, as shown in FIG. 3, developer sealing materials 45 and 46 are provided at both ends of the developing roller 34, and as shown in FIG. By stacking it on top of the leak prevention sheet 52, the operation of the developer leak prevention sheet 52 can be made more reliable. Reference numeral 51 denotes a developer leak prevention member made of metal such as stainless steel or aluminum, and prevents the developer from falling downward even if the developer leaks from the gap in the developer leak prevention sheet 52. In this case, the developer leak prevention sheet 52
Since leakage of the developer 28 is almost completely stopped by this, the capacity of the developer leak prevention member 51 may be small. Further, as shown in FIG. 2(b), by bending the upper part of the downstream side wall of the developer leak prevention member 51 toward the downstream side and bringing its tip into contact with the fur brush 35, the excess that has adhered to the fur brush 35 is removed. Scrape off the developer 28 of
The developing agent 28 can be returned into the container 9, and leakage of the developer 28 can be more reliably prevented. Reference numeral 53 denotes a voltage applying means, which applies a voltage of opposite polarity to the developer 28 between the fur brush 35 and the developer leak prevention member 51 to attract the developer 28 toward the fur brush 35. If leakage of the developer 28 is more reliably prevented, 14 pages can be created. In addition, when the voltage application means 53 is not used, it is also effective to form the developer leak prevention member 51 integrally with the cover 29.

The operation of the developing device of the first embodiment configured as described above will be explained.

Here, in order to make the operation easier to understand, the photosensitive drum 22
The upper photoconductor 24 is made of selenium, and the cylindrical elastic body 35 is made of carbon-containing rayon fiber 36 having a specific resistance of about 105 Ωem as an elastic material 37 on an aluminum core 36.
A fur brush with approximately 00 hairs/cm2 flocked, the surface roughness of the developing roller 34 is 5 μmRmax, the linear pressure of the blade 44 that presses against the developing roller 34 is 25 g/Cm, the gap between the photosensitive drum 22 and the developing roller 34 is 0° 15 mm,
The developer 28 is a normal positively charged non-magnetic one-component toner, the developer leak prevention sheet 52 is a urethane rubber sheet with a thickness of 90 μm, and the developer leak prevention member 51 has a thickness of 0.3 μm.
An experiment was conducted by using a stainless steel plate of 1.0 mm in diameter and applying a DC voltage of 100 μm using the voltage applying means 53 with the side of the developer leak prevention member 51 being positive. A bias of +700 V was applied to the developing roller 34 with respect to the photosensitive drum 22 by a high-voltage power supply 48 for direct 15-page flow. Also, the speed of the outer peripheral surface of the photosensitive drum 22 is 150 mm.
/see, the speed of the outer peripheral surface of the developing roller 34 is 150 mm
It was driven at a speed that periodically fluctuated finely within a range of plus or minus about 20% with /see as the center.

In FIG. 1, the charger 25 is connected to a first high-voltage DC power source 26.
A high voltage of about +6 kV is applied, and the entire surface of the photosensitive drum 22 is negatively charged to about +800 V by the positive corona. Next, by irradiating the positively charged photosensitive drum 22 with a light beam modulated according to the signal by the optical section 27, static electricity is removed from the portion of the photosensitive drum 22 corresponding to the image area of the document to a residual potential close to 0■. Forms a negative electrostatic latent image. Meanwhile, the developer 2 in the body 29
8 is a fur brush 35 by rotating the fur brush 350 times.
supplied within. Next, the excess developer 28 in the fur brush 35 is scraped off by a scraping plate 38 and an appropriate amount is supplied, and the developing agent 28 is positively charged by friction with the scraping plate 38 and the developer 29. Further, this developer 28 is applied to the fur brush 3.
5, the developer 28 is conveyed to a position facing the developing roller 34, and the surface of the developing roller 34 is coated with the charged developer 28. At this time, the developer 28 supplied in an appropriate amount is further uniformly charged positively due to the agitation effect caused by the rotation of the fur brush 35 and the friction with the surface of the developing roller 34.

At this time, no voltage is applied between the developing roller 34 and the fur brush 35, and since the photosensitive drum 29 is electrically insulated from the photosensitive drum 22 and the developing roller 34, no voltage is applied between them. It does not occur that the highly charged developer 28 is easily transferred as it would be when the voltage is applied.

Therefore, for example, developer 2 that was not used for development
Even if the developer 28 is scraped off and transferred again, only a part of the developer 28 will not be overcharged, and the developer 28 will not be overcharged.
8 is uniformly charged. Therefore, a good image can be obtained. According to the inventor's experiments, when looking from the ground side, applying -200 VDC to the developing roller 34, -120 VDC to the fur brush 35, and grounding the power supply 29, fogging occurred due to uneven charging (page 17). After observing the occurrence of toner lumps and toner clumps, we conducted further continuous tests.
Due to overcharging of a portion of the developer 28, problems occurred such that the image density measured with a densitometer decreased from 1.2 to 0.8 after about 150 sheets. On the other hand, as in this embodiment, the developing roller 3
When no voltage is applied between the developer 29 and the fur brush 35 and the photoreceptor 29 is electrically insulated from the photosensitive drum 22 and the developing roller 34, the amount of charge on the developer 28 becomes 3.
It was made uniform to ~6 μC/g, good images were obtained even in continuous tests, and no decrease in image density was observed.

In this development process, an appropriate amount of developer 2 is placed inside the fur brush 35.
8, therefore the fur brush 35 and the developing roller 34
Since the contact resistance is high, the current value of the detection means 43 is small. Next, the developing process is repeated, and when the developer 28 in the barrier body 29 and the developer 28 in the fur brush 35 are used up, the contact resistance becomes lower and the current value of the detection means 43 becomes larger. Therefore, the presence or absence of the developer 28 in the transparent body 29 can be detected based on the current value of the detection means 43. Further, the elastic member 33 repeats the development process,
When the amount of the developing agent 28 in the body 29 decreases, the developer 28 is displaced as shown in FIG.
5 direction. Therefore, even if the angle of inclination of the bottom surface of the cover body 29 is small, the developer 28 of the cover body 29 can be supplied to the fur brush 35 without any problem until the end. Therefore, the amount of developer 28 in the housing 29 can be increased, and the developer 28 can be supplied with a simple and inexpensive structure. Although the elastic member 33 is provided on the lid 32 in this embodiment,
It is clear that the same effect can be obtained by providing the cover on the bottom side of the cover 29.

The thickness of the coated developer 280 layer on the surface of the developing roller 34 is greater than a predetermined thickness, and there is some variation. Next, as the developing roller 34 rotates, the charged developer 28 on the surface of the developing roller 34 is partially scraped off by the blade 44 as it passes through the blade 44, resulting in a predetermined layer thickness of approximately 4.0 μm (
The layer thickness at this time is preferably regulated to about 10 μm to 70 μm). The developer 28 that came into contact with the blade 44 at this time
is moved from the center of the developing roller 34 toward both ends, and is moved from both ends of the fur brush 35 to the center by the rotation of the fur brush 35, which has the basic shape of the spy 19.

Therefore, the developer 28 near both ends of the developing roller 34 and the fur brush 35 does not increase, and the height of the developer 28 in the cover body 29 is kept constant. Further, since the developer sealing materials 45 and 46 that are in contact with both end surfaces of the blade 44 are in contact with the smooth surfaces of the outer peripheral surfaces 34a and 34b at both ends of the developing roller 34, there is no wear even when the developing roller 34 rotates. Very few. Further, the joint surfaces of the developer sealing materials 45 and 46 that come into contact with the blade 44 and the developing roller 34 are smooth surfaces, and no gaps are generated at the joint portions. Therefore, there is no leakage of the developer 28 due to the force pushed in the axial direction of the developing roller 34. In addition, since the developer reservoir in the housing 29 is not provided upstream of the position where the developing roller 34 and the fur brush 35 face each other with respect to the moving direction of the developing roller 34, the developer 28 may leak or scatter. disappears.

Next, the negative electrostatic latent image on the photosensitive drum 22 is transferred to the developing roller 3.
When the developer 28 faces the positively charged developer 28 on the photosensitive drum 22 and the developing roller 34, the electric field generated by the bias between the photosensitive drum 22 and the developing roller 34 causes the developer 28 to fly to the image area near Ov of the electrostatic latent image, and the latent image is can be developed. At this time, the outer circumferential surface of the photosensitive drum and the developer on the developing roller have a relative velocity in the vertical direction at small intervals, so the reproducibility of fine lines and image edges is lower than in the case of normal development at the same speed. Develops well. That is, in this type of development method, the electric field generated in the space between the photoreceptor and the developing roller causes the developer on the developing roller to fly off and adhere to the latent image, and at the edges of the latent image, the direction of the electric field is Since the image is turned sideways, the developer in the area facing the edge tends to concentrate toward the center of the image, and sufficient developer does not adhere to it. If the relative speed is zero, the amount of developer on the developing roller facing the image will decrease, as shown in Figure 6 (
As shown in a), the edges of the image become sloppy due to less developer adhesion, and as shown in Fig. 6(b), fine lines are developed as thin, and even in the case of very fine lines. may not be reproduced. In the 21st <- white diagram, 22 is a photoreceptor drum, A represents the image area of the negative latent image formed on the photoreceptor drum 22, and 56 represents the electric field generated between the photoreceptor drum and the developing roller. It shows. This phenomenon is caused by the DC electric field between the photosensitive drum surface and the developing roller when the photosensitive drum and the developing roller are directly electrically connected as in this embodiment or when they are connected by a DC high-voltage power supply. It appears especially when developing with .

Therefore, by creating a relative speed between the photoreceptor and the developing roller as in this embodiment, for example, the relative speed of the developing roller to the photoreceptor in the left direction of the paper is increased as shown by arrow B in FIG. In some cases, more developer will be deposited on the right edge of the latent image than if the relative velocity were zero. this is,
When the relative speed is zero, as shown in Figure 6, once the electric field has been developed, the electric field is still in almost the same shape as before development, but the area of the developing roller that faces the latent image is originally 40 μm thick. Since the remaining developer is a relatively thin layer, the remaining developer is decreasing or has disappeared. However, if there is a relative speed, for example, in the case of Figure 7, page 22 is filled with new developer from the right side. This phenomenon occurs because the right side of the edge is further developed as shown by the arrow 57 since the edge is brought to the opposing portion. This phenomenon is completely different from the non-uniformity of image density as disclosed in No. 54-43027 in terms of the relationship between the direction of relative velocity and the direction in which high-density areas are formed, and the range in which high-density areas are formed. be. That is, according to the authors' experiments, at a relative speed of about 20%,
An image was reproduced with edges in the above-mentioned direction with respect to the direction of relative velocity, and where the density of only the edges was high, with no effect on the solid areas. This is a phenomenon unique to the developing method of the present invention. In the case of this embodiment, since there is a relative speed between the photoreceptor and the developing roller at fine intervals in the vertical direction of FIG. 1, an image is obtained in which both the upper and lower edges of the image are emphasized and the reproducibility of fine lines is good.

In this embodiment, the photosensitive drum is rotated at a constant speed and the developing roller is rotated at a variable speed by a pulse motor, but the same effect can be obtained by rotating the developing roller at a constant speed and rotating the photosensitive drum at a variable speed.

The surplus developer that was not used for development is carried further downstream while adhering to the developing roller 23 and the pager 34 and passes through the developer leak prevention sheet 52. However, the developer leak prevention sheet 5
Since the developer 28 is only lightly in contact with the developing roller 34, the developer 28 is carried as it is into the developer 29 by the adhesive force, and once it has passed through the developer leak prevention sheet 52, it will not leak out again. do not have. Further, the voltage applying means 53 is used to set the side of the developer leak prevention member 51 to a positive value of 100.
Since the DC voltage (2) is applied, the developer 28 that is about to leak is attracted to the fur brush side, and the leakage prevention effect is further enhanced.

Further, as described above, even if a very small amount of the developer 28 leaks, the developer leak prevention member 51 prevents it from being caught and contaminates the developing device and equipment below. After development, the developer 28 adhering to the surface of the developing roller 34 is scraped off by the fur brush 35, and the second DC high voltage power source 4 is turned on only during the period when no development is performed.
2, a voltage of opposite polarity to that during development is applied between the developing roller 34 and the fur brush 35 (the applied voltage at this time is preferably about 30 V to 25 QV, and in this embodiment, 100 V is applied. ) The surplus developer on the developing roller 34 is attracted to the fur brush 35 side by an electric field, and the development history on the developing roller 34 is erased. Therefore, a high-quality image without ghosts can be obtained. In other words, the present developing device can uniformly charge the developer 28 on the developing roller 34 and make the layer thickness uniform, and furthermore, there is no scattering or leakage of the developer 28, and there is no fogging or density unevenness. It is possible to obtain high-quality images without any blemishes. In addition, in this developing device, since the developer 28 is stirred and frictionally charged by the rotation of the far flage 35, the rise time until the developer 28 is charged to a predetermined amount of charge is short, and the predetermined amount of charge can be reached within 1 sec. , so there is no need for extra waiting time.

Furthermore, as described above, the present developing device has a simple configuration and is small in size. In addition, since the toner does not leak or scatter, restrictions on the arrangement of the developing device can be reduced.

In this example, we have explained an example in which a 25-page experiment was performed for reversal development (negative-positive development) in a laser beam printer, but this book also describes regular development (positive-positive development) in an electrophotographic copying machine, etc. It goes without saying that the invention can be applied.

Next, a second embodiment of the present invention will be described.

FIG. 8 is a top view of the developing section in a second embodiment of the present invention. Components having the same functions as those in the first embodiment are given the same numbers. A developing device 58 has the same structure as in the first embodiment, and its developing roller is similarly driven by the pulse motor 55. The entire developing device is biased rightward by a spring 59, and a magnetic body portion 6 provided on the left side
0 and the electromagnet 61 allows it to move to the left against the spring 59. 62 is a power source for the electromagnet 61. In this embodiment, the internal operation of the developing device is the same as in the first embodiment, but during development, a periodically fluctuating input is applied to the electromagnetic field 561 by the power source 62 to move the developing device 58 in the left and right direction in FIG. make it vibrate. This creates a relative speed in the horizontal direction between the photosensitive drum 22 and the developing roller, and the same effect as described in the first embodiment can be obtained even for edges and thin lines in the horizontal direction of the image. It is something.

In addition, the present invention is well suited to non-magnetic component developers, has a non-contact structure with the latent image carrier, and can develop high-quality images using a DC electric field. It is also advantageous for the formation of color images that are developed by overlapping them. In other words, since development is performed using a DC electric field, a new image of a different color can be developed without disturbing the previously developed developer image on the photoreceptor, unlike when developing using an AC electric field. It is possible to form a color image by batch transfer.

Effects of the Invention According to the present invention, a high-quality image can be formed without rounding of edges, thinning of fine lines, or defects in fine lines that occur in a developing method in which development is performed without contacting a photoreceptor.

Furthermore, according to the present invention, the above-mentioned high image quality can be achieved without reducing the distance between the photoreceptor and the developing roller, so a stable device with a large margin can be obtained with a simple configuration.

Page 27 Furthermore, the present invention exhibits this feature very well in non-contact fly development using a DC electric field of a non-magnetic component developer, and high-quality images can be obtained with a simple configuration. The object of the present invention is to provide an image forming method that is advantageous for forming color images in which color developers are developed by overlapping them.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an image forming apparatus according to a first embodiment of the present invention, and FIGS. 2, 3, and 4 are configurations of each part of an image forming apparatus according to a first embodiment of the present invention 5 is another sectional view of the image forming apparatus according to the first embodiment of the present invention, FIG. 6 is an explanatory diagram of the developing state according to the conventional developing method, and FIG. 7 is an explanatory diagram of the developing state according to the present invention. FIG. 8 is a plan view of an image forming apparatus according to a second embodiment of the present invention, and FIG. 9 is a sectional view of a main part of a conventional image forming apparatus. 22... Photosensitive drum, 28... Developer, 29...
Covering body, 33... Elastic member, 34... Developing roller, 35... Fur brush, 38... Scraping plate, 3
9... Partition plate, 42... DC high voltage power supply, 43...
- Detection means, 44... Blade, 47... Pressing spring, 48... DC high voltage power supply, 49... Swinging member, 51
... Developer leak prevention member, 52 ... Developer leak prevention sheet, 53 ... Voltage application means, 54 ... Motor,
55...Pulse motor, 58...Developer, 61...
・Name of electromagnet agent Patent attorney Toshio Nakachi One idiot Figure 2 ((:lJ +!) γ Figure 3 Figure 4 Figure 6 Figure 8 Figure 7 Figure 9:34

Claims (4)

[Claims] (1) A latent image carrier having an electrostatic image, a developer carrier provided opposite to the latent image carrier, and a thin layer forming means for forming a thin layer of developer on the developer carrier. a distance is provided between the surface of the latent image carrier and the developer on the developer carrier at the development position, and a distance is provided between the surface of the latent image carrier and the developer on the developer carrier at the development position. An image forming apparatus having a drive means controlled to create a relative speed during development between the developer and the developer. (2) Claim 1, wherein the driving means comprises a latent image holding member driving means for driving the latent image holding member at a constant speed, and a developer carrying member variable speed driving means for driving the developer carrying member at variable speeds. The image forming apparatus described above. (3) Claim 1, wherein the driving means comprises a latent image holding member driving means for driving the latent image holding member at a variable speed, and a developer carrying member driving means for driving the developer carrying member at a constant speed. image forming device. (4) A developer carrier in which the developer carrier has a cylindrical shape and the drive means includes a rotary drive unit that rotates the developer carrier around the cylindrical axis and a reciprocating drive unit that causes the developer carrier to reciprocate in the axial direction of the cylinder. An image forming apparatus according to claim 1, 2 or 3, comprising a driving means and a latent image holding member driving means.