JPH0365964A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to an image forming apparatus, and particularly relates to an image forming apparatus, and particularly, even when ozone, NOX, etc. are generated during secondary charging, recharging, etc., the present invention can be performed satisfactorily without causing image deletion or the like in a toner image. The present invention relates to an image forming apparatus capable of forming toner images of multiple colors.

Ai Wei Ri Ni I At present, electrostatic recording methods using electrophotography are often applied to printers serving as terminal devices for information equipment such as computers, facsimiles, and CAD.

In these printers, the information signal is transmitted using a laser beam, LE
A D%LCD or the like is used to write an electrostatic latent image on the photoconductor of an image carrier, and the electrostatic latent image on the photoconductor is developed with a developer using a developing device to visualize it as a toner image. The toner image is transferred onto a transfer material by a transfer device, and the toner image transferred onto the transfer material is fixed by a fixing device to obtain a recorded image of information on the transfer material.

Conventionally, the information recorded above has generally been recorded on a transfer material in a single color such as black. However, recording images are formed in multiple colors so that they can be distinguished, such as recording calculated values or data values in a color different from the format color, or recording a part of a drawing output by CAD in a different color. This is useful for understanding information better. For this reason, image forming apparatuses that form multicolor images using an electrostatic recording method have been proposed.
Such image formation is also being carried out.

Next, an image forming method will be explained by taking as an example a two-color image forming apparatus which is a basic multicolor image forming apparatus.

As shown in FIG. 5, the two-color image forming apparatus has a photosensitive drum l as an image carrier. The photosensitive drum 1 is
A photoconductive layer is coated and formed on a conductive substrate. The circumferential surface of the photosensitive drum 1 is uniformly charged by a primary charger 2, and the information signal 3 of the first color is exposed onto the photosensitive drum 1 by a light emitting element such as a laser. A first color electrostatic latent image is formed, and the first color electrostatic latent image is developed with a first color developer by a first developing device 4 to form a first color toner image on the photosensitive drum 1. get.

Next, after the photosensitive drum 1 is overcharged by the recharging unit 7, the information signal of the second color is exposed in the same manner to form an electrostatic latent image of the second color, and the second developing unit 6 is used to overcharge the photosensitive drum 1. It is developed with a second color developer to obtain a second color toner image.

The first color obtained on the photosensitive drum 1 as described above,
The second color toner image is then transferred onto the transfer paper 9 of the transfer material by applying a transfer electric field by the transfer charger 8, and then fixed onto the transfer paper 9 by the fixing device 10. In this way, a two-color recorded image is obtained on the transfer paper 9.

In FIG. 5, reference numeral 11 denotes a cleaning device for removing residual toner on the photosensitive drum 1 after transfer.

In this two-color image forming apparatus, the photosensitive drum 1
The first color toner image formed on the photosensitive drum 1 adheres to the circumferential surface of the drum 1 due to the reflection force with the photosensitive drum 1.
If this adhesion is weak, a problem arises in that toner scatters from the first color toner image and mixes into the second developing device 6 when the second color toner image is developed.

In order to solve this problem, it is recommended that the first color toner image be developed using a two-component magnetic brush developer using a two-component developer consisting of non-magnetic toner and magnetic particles (carrier). ing. This is because when using a two-component magnetic brush method, the amount of charge on the toner is higher than when using a single-component developing method using magnetic toner, so the mirroring force with the photosensitive drum is also stronger. .

In this case, if the toner image of the first color is recharged with the same polarity as that of the toner, the amount of charge of the toner will increase and the adhesion to the photosensitive drum 1 will become stronger.
It becomes possible to more effectively prevent toner from entering the second developing device 6 from a colored toner image.

Regarding the method of developing the second color toner image using the second developing device 6, in order to avoid disturbing the first color toner image on the photosensitive drum 1, it is preferable to use a non-contact developing method. Preferably, for example, a jumping development method using a -component magnetic toner is said to be suitable.

However, when a printer is operated by repeating the image forming process described above, low-resistance substances such as ozone and NOx generated by corona discharge during primary charging etc. are generated on the surface of the photosensitive drum 1. As a result, the charges forming the electrostatic latent image on the photosensitive drum 1 are diffused. Therefore, if the toner image is developed in this state, the obtained toner image may be blurred or the image may be washed out.

In particular, in a multicolor image forming apparatus such as the two-color image forming apparatus of this method, it is necessary to form images in multiple colors, and the photosensitive drum l is charged each time, and the charging is performed in addition to the primary charging. Since recharging is performed, a large amount of ozone and the like is generated, which tends to cause image deletion. Moreover, the higher the humidity in the environment, the more this tendency becomes noticeable.

Therefore, in order to solve this problem, conventional methods have been adopted in which ozone and other substances generated during negative charging and recharging are collected by an exhaust fan, adsorbed by an activated carbon filter, decomposed, and discharged outside the machine. It is being

However, in the conventional method, the generated ozone, etc. is adsorbed and decomposed only on the photosensitive drum, which has problems such as image deletion.
Therefore, although there is an effect of not emitting harmful ozone etc. to the outside of the machine, it is not very effective in removing ozone etc. near the photosensitive drum 1 which adversely affects images.

Generally, in the vicinity of the photosensitive drum 1, it is necessary to arrange a large number of devices including the developing device 4.6 in a limited space, and the density of these devices is extremely high, resulting in the emission of ozone, etc. It is not possible to secure sufficient ventilation routes for this purpose. For this reason, even if the exhaust air volume of the exhaust fan is increased, the effect of removing ozone and the like near the photosensitive drum 1 will not improve much, and this will not solve the problem.

For this reason, in conventional multi-color image forming apparatuses including two-color image forming apparatuses, low-resistance substances such as ozone and NOx generated during secondary charging are used to hold images on photosensitive drums, etc. There have been many cases in which toner image smearing and image blurring occur due to adhesion to the body.

Therefore, it is an object of the present invention to provide that even if ozone, NOx, etc. are generated during secondary charging or recharging, low-resistance substances caused by the ozone, NOx, etc. adhere to an image carrier such as a photosensitive drum. It is an object of the present invention to provide an image forming apparatus that can prevent the occurrence of image smearing or blurring of toner images, and can satisfactorily form toner images of a plurality of colors.

The above object is achieved by the image forming apparatus of the present invention. To summarize, the present invention develops electrostatic latent images of a plurality of colors sequentially formed on an image carrier with a developer using a developing device corresponding to each electrostatic latent image, thereby producing toner of a plurality of colors. form an image,
After that, in an image forming apparatus that transfers the plurality of color toner images onto a transfer material, toner of a developer used in a developing device corresponding to a first color electrostatic latent image of the plurality of color electrostatic latent images; This image forming apparatus is characterized in that an ozone adsorbent is externally added to the image forming apparatus.

According to one aspect of the invention, the ozone adsorbent is preferably an activated carbon powder or a hobcalite catalyst. Further, an adsorbent chamber containing the ozone adsorbent is provided in the developing device corresponding to the electrostatic latent image of the first color, and a supply amount adjusting means for the ozone adsorbent is disposed below the adsorbent chamber. be done.

Natsuki's father-in-law Examples of the present invention will be described in detail below.

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

As shown in FIG. 1, the image forming apparatus of the present invention is a two-color image forming apparatus, including a photosensitive drum 1 as an image carrier, a first developing device 4, a second developing device 6, Transfer drum 1
2 and a fixing device 10. Around the photosensitive drum l, a -forming charger 2 and the above-mentioned first developing device 4 are installed.
, a recharging device 7 and the second developing device 6 described above are provided,
Furthermore, a cleaning device 11 is provided.

The photosensitive drum 1 is an OPC (organic photoconductor) drum formed by coating and forming an organic photoconductive layer on a conductive substrate, and rotates in the direction of the arrow in the figure.

The first developing device 4 includes a developing container 44 , a developing sleeve 41 installed in the container 44 and rotating in the A direction, a magnet 42 immovably installed in the developing sleeve 41 , and a developing sleeve 41 installed above the developing sleeve 41 . It consists of a blade 43 installed. A two-component developer 45 made of non-magnetic negative polarity toner and magnetic particles (carrier) is housed in the developer container 44 .

The second developing device 6 similarly includes a developing container 4 , a developing sleeve 61 installed in the container 64 and rotating in direction B, a magnet 62 immovably installed in the developing sleeve 61 , and a developing sleeve 61 installed in the developing sleeve 64 . It consists of a blade 63 installed above.

A one-component developer 65 made of magnetic toner is housed in the developer container 64 .

In the above configuration, the circumferential surface of the photosensitive drum 1 is primarily negatively charged by the charger 2, and information whose light intensity is modulated by a light emitting element such as a laser based on the image information of the first color is generated. By exposing the signal 3 to light, an electrostatic latent image of the first color is formed on the circumferential surface of the photosensitive drum 1. Next, the first developing device 4 uses a two-component developer 45 made of non-magnetic negative polarity toner and magnetic particles to reversely develop the electrostatic latent image of the first color on the photosensitive drum 1 using a magnetic brush development method. Then, a first color toner image is obtained.

Next, after the photosensitive drum 1 is negatively charged again by the recharger 7, an information signal 5 based on the image information of the second color is exposed to form an electrostatic latent image of the second color on the photosensitive drum 1. ,
A second developing device 6 uses a one-component developer 65 made of magnetic toner to develop the photosensitive drum 1 by a jumping development method.
The upper second color electrostatic latent image is reversely developed in a non-contact manner to obtain a second color toner image.

The first color obtained on the photosensitive drum 1 as described above,
The second color toner image is then transferred onto the transfer paper 9 of the transfer material carried by the transfer drum 12 by applying a transfer electric field by the transfer charger 8 provided inside the transfer drum 12. Later, the transfer paper 9 is fixed by the fixing device 10.
fixed on top. In this way, a two-color recorded image is obtained on the transfer paper 9.

After the transfer has been completed, the photosensitive drum 1 is subjected to the image formation described above again after the residual toner thereon is removed by a cleaning device 11 and the residual surface charge is removed by an eraser lamp (not shown).

According to the present invention, an ozone adsorbent 46 is externally added in advance to the non-magnetic negative polarity toner of the two-component developer 45 used in the first developing device 4. This ozone adsorbent 46 is
- This is for adsorbing and removing ozone, NOx, etc. near the photosensitive drum 1 generated during charging and recharging. A metal oxide, such as a hobucalite catalyst, can be used.

The amount of the ozone adsorbent 46 externally added to the toner may be determined as appropriate depending on the amount of ozone generated and the type of ozone adsorbent, since the adsorption ability for ozone, NOx, etc. differs depending on the type of the ozone adsorbent 46. .

For example, when activated carbon powder with an average particle size of 0.1 μm is used as an ozone adsorbent, in the image forming apparatus configured as in this example, the inventors of the present invention applied activated carbon powder to non-magnetic negative toner with an average particle size of 12 gm. According to the results of experiments with different external addition ratios, when the added amount of activated carbon powder is less than 1 wt% O, adsorption of ozone, etc. is insufficient for the amount of generated ozone, etc., and ozone, etc. Adhesion of low-resistance substances occurs due to
As a result, it has not been possible to prevent image deletion and image blurring from occurring in toner images of the first color and the like. On the other hand, when the amount of activated carbon powder added exceeds 10% wt, the activated carbon powder was transferred onto the transfer paper, resulting in fogging of the first color toner image.

In general, in order to maintain toner properties and not affect development conditions, ozone adsorbents are used with particle sizes of 0.0
1-1. OILm is added in an amount of 0.1 to 10.0 wt%, preferably 0.5 to 5 wt%. At this time, the particle size of the toner is suitably in the range of 5 to 15 μm.

Note that the one-component developer 65 made of toner used for developing the second color toner image generally has a low charge amount of toner particles and is unstable. For this reason, if an ozone adsorbent is externally added to the toner of the -component developer 65, the charge distribution of the toner will change and there is a risk that the development characteristics will change significantly. No ozone adsorbent is externally added to toner No. 65.

The image forming apparatus of the present invention is configured as described above. According to this, when the electrostatic latent image of the first color formed on the photosensitive drum 1 is developed by the first developing device 4 using the developer 45, an ozone adsorbent 46 is deposited on the photosensitive drum 1. A first color toner image made of toner externally added is applied.

After the first color toner image is developed, the ozone adsorbent 46 in the first color toner image recharges the photosensitive drum 1 to form a second color electrostatic latent image, and the second color toner image is developed. After the toner image of the second color is developed by the device 6 and until the toner images of the first and second colors on the photosensitive drum l are transferred onto the transfer paper 9, charging and recharging are performed. It continues to absorb and remove ozone, NOx, etc. generated near the photosensitive drum 1.

Therefore, it is possible to prevent low-resistance substances such as ozone and NOX from adhering to the photosensitive drum 1, and to prevent image deletion and blurring of the first and second color toner images on the photosensitive drum 1. It can be prevented.

FIG. 2 is a configuration diagram showing the main parts of another embodiment of the image forming apparatus of the present invention.

In this embodiment, in order to stabilize the amount of externally added ozone adsorbent 46 to the non-magnetic negative polarity toner of the two-component developer 45 used in the first developing device 4, as shown in FIG. In this way, an adsorbent chamber 48 containing an ozone adsorbent 46 is provided in the developing container 44, and the ozone adsorbent 46 is gradually added externally within the developing container 44 without adding the entire amount to the toner externally in advance. It is characterized by the fact that it is made as follows. The other configuration of the image forming apparatus of this embodiment is basically the same as the image forming apparatus shown in FIG. 1, and the same reference numerals in FIG. 2 as in FIG. 1 indicate the same members. .

The adsorbent chamber 48 is provided in the developing container 44 of the first developing device 4 on the side opposite to the photosensitive drum 1, and is located above the stirring screw 49 provided at the lower part of the developing container 4. A supply amount adjusting means 47 for the housed ozone adsorbent 46 is provided in the opening at the bottom of the adsorbent chamber 48 .

As shown in FIG. 3, the supply amount adjusting means 47 includes a cylindrical regulating member 5 having a size that partitions the lower opening of the adsorbent chamber 48.
0, a plurality of supply passages 51 penetrating in the radial direction are provided at intervals in the axial direction. The adjustment means 47 is driven by the rotation of the developing sleeve 41, and the regulating member 50 rotates in accordance with the rotation of the developing sleeve 41.

According to such a supply amount adjusting means 47, when the regulating member 50 rotates due to the rotation of the developing sleeve 41 and the supply path 51 faces in the height direction of the adsorbent chamber 48, the adsorbent chamber 48
The ozone adsorbent 46 inside passes through the supply path 51 of the regulating member 50, falls onto the stirring screw 49, is supplied, and is mixed with the two-component developer 45 inside the developing container 44 by the screw 49, so that the ozone adsorbent 46 is externally added to the non-magnetic negative polarity toner in the developer 45. As the developing sleeve 41 rotates, the regulating member 50 further rotates, and when the supply path 51 faces in a direction perpendicular to the height direction of the adsorbent chamber 48, the supply of the ozone adsorbent 46 from the adsorbent chamber 48 is stopped. be done.

Therefore, the ozone adsorbent 46 is supplied to the adsorbent at an amount corresponding to the rotational speed of the developing sleeve 41, that is, the frequency of developing the first color toner image using the two-component developer 45 in the first developing device 4. The ozone adsorbent 46 can be externally added to the toner of the two-component developer 45 by being supplied from the chamber 48 to the two-component developer 45 in the developing container 44, and the amount of the ozone adsorbent 46 externally added to the toner of the two-component developer 45 can be adjusted. can be stabilized over time.

The adsorbent supply amount adjusting means 47 only needs to be able to supply the ozone adsorbent 46 to the toner of the two-component developer 45 at a supply amount corresponding to the frequency of development of the first color toner image, as shown in FIG. It is not limited to the configuration.

In this image forming apparatus, an ozone adsorbent 46 is externally added from the adsorbent chamber 48 to the toner of the two-component developer 45 in the first developer container 44 by the supply amount adjusting means 47 to form a toner image of the first color. FIG. 4 shows the relationship between the change in the weight ratio of the adsorbent externally added to the toner and the number of prints when a two-color image is printed during development.

The two-component developer 45 in the developing container 44 contained toner equivalent to 5,000 A4 size sheets at a dot ratio of 4%.

The ozone adsorbent 46 is externally added at a weight ratio of 0.5% to the toner in advance, and after that, every time 1000 sheets are printed, the supply amount adjustment means 47 is used to add the ozone adsorbent 46 to the toner for a time corresponding to the printing time of 100 sheets. The ozone adsorbent 46 is supplied from an adsorbent chamber 48 to be externally added to the toner.

As shown in FIG. 4, when the ozone adsorbent 46 is externally added to the toner of the two-component developer 45 in the developer container 44 using the supply amount adjusting means 47 under the above conditions, the ozone adsorption of the toner is External addition amount of agent 4°6 at weight ratio of 0.25 to 0.75
Ozone adsorbent 4.
It was possible to stabilize the external addition amount of 6 over time.

Then, a first color toner image made of toner externally added with an ozone adsorbent 46 is formed on the photosensitive drum 1, and the first color toner image is formed on the photosensitive drum 1.
The ozone adsorbent agent 46 in the colored toner image absorbs ozone, NOX, etc. near the photosensitive drum 1 generated during primary charging and recharging, and continues to remove it, thereby removing low-resistance substances such as ozone and NOX. It was possible to prevent the toner from adhering to the photosensitive drum 1, and to prevent image deletion and image blurring from occurring in the first and second color toner images on the photosensitive drum 1.

Even if the image forming apparatus described above is used as a so-called process cartridge system in which the photosensitive drum 1, charger 2.7, developing units 4, 6, cleaning device 11, etc. are integrated, ozone adsorption occurs during use. There is an advantage that the external addition ratio of the agent 46 to the toner does not drop too much, and image blurring of toner images can be effectively prevented.

In each of the above embodiments, a two-color image forming apparatus has been described, but the present invention is not limited thereto, and an image forming apparatus using three or more colors may also be used to develop a toner image of the first color. By externally adding an ozone adsorbent to the developer toner, ozone and N generated during secondary charging and recharging can be removed.
By preventing low-resistance substances caused by OX etc. from adhering to the photosensitive drum, toner images of multiple colors can be formed satisfactorily without causing image deletion or the like in toner images of the first color, etc.

As described above, in the image forming apparatus of the present invention, electrostatic latent images of multiple colors sequentially formed on an image carrier are processed using a developer using a developing device corresponding to each electrostatic latent image. When sequentially developing toner images of multiple colors, an ozone adsorbent is externally added to the toner of the developer used in the developing device that corresponds to the electrostatic latent image of the first color. Even if ozone, NOX, etc. are generated during recharging, it prevents low-resistance substances caused by the ozone, NOX, etc. from adhering to the image bearing member such as the photosensitive drum, and prevents image blurring of toner images. Toner images of multiple colors can be formed satisfactorily without causing image blur.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention. FIG. 2 is a configuration diagram showing the main parts of another embodiment of the image forming apparatus of the present invention. 3 is a perspective view showing an adsorbent supply amount adjusting means used in an adsorbent chamber provided in the first developing device of the image forming apparatus shown in FIG. 2. FIG. FIG. 4 is a graph showing an example of the relationship between the change in the weight ratio of the ozone adsorbent externally added to the toner of the two-component developer in the first developing device of the image forming apparatus shown in FIG. 3 and the number of copies. . FIG. 5 is a configuration diagram showing an example of a conventional image forming apparatus. 1: 2, 7. 4: 45 = 46: 47: Photosensitive drum 8: Charger 1st developer Two-component developer Ozone adsorbent supply amount adjusting means 1st Figure 4 000 000 000 000 5000 Figure 5

Claims (1)

[Claims] 1) Electrostatic latent images of multiple colors sequentially formed on an image carrier,
In an image forming apparatus that sequentially develops each electrostatic latent image with a developer using a developer to form a plurality of color toner images, and then transfers the plurality of color toner images onto a transfer material. . An image forming apparatus characterized in that an ozone adsorbent is externally added to a toner of a developer used in a developing device corresponding to a first color electrostatic latent image of the plurality of color electrostatic latent images. 2) The image forming apparatus according to claim 1, wherein the ozone adsorbent is activated carbon powder or a hobcalite catalyst. 3) An adsorbent chamber containing the ozone adsorbent is provided in the developing device corresponding to the first color electrostatic latent image, and a supply amount adjusting means for the ozone adsorbent is disposed in a lower part of the adsorbent chamber. The image forming apparatus according to claim 1 or 2, further comprising: