JPH07295344A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent deterioration of a recording head, ink, etc., by reducing ozone which is generated by an image forming means of an electrophotographic system. CONSTITUTION:A white and black toner image is formed by the upstream image forming means I of the electrophotographic system, and a color ink image is also formed by a downstream image forming means II of an ink jet system. A photoreceptor drum 1 is electrified by an electrifying roller (contact electrifying member) which is in contact with the surface of the photosensitive drum 1. Thus, because ozone which is generated at the time of electrification is reduced, deterioration of the recording head 25a and ink in the ink jet system due to ozone is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a plurality of image forming means of different image forming systems.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic system, an inkjet system, a thermal transfer system and the like are well known as an output unit (image forming unit) for outputting image information in which a color image and a monochrome image are mixed.

Among them, the image forming apparatus which employs the electrophotographic method and forms an image with toner can output a high-quality image at high speed, but on the other hand, due to colorization, the size of the entire apparatus is increased and the cost is increased. It is not suitable for use as a desktop printer because it is difficult to achieve maintenance-free.

On the other hand, the image forming apparatus using the ink jet method or the thermal transfer method is suitable as a desktop printer because it can be downsized, the cost can be reduced, and the maintenance is easy. However, when a black-and-white character image or the like is output, there is a problem in image sharpness and printing speed (output speed). It is difficult to form high-quality images when plain paper is used as the recording material, and it is necessary to use special paper such as coated paper specified by the manufacturer as the recording material in order to output relatively high quality. Is. Further, when used as a desktop printer in a general office or the like, the printing speed of a black-and-white image, which is frequently used, is slow and the work efficiency is lowered. In addition, in the ink jet system, the density of the ink itself is lower than that of the toner, so that the blackness of characters is lacking, and when characters are output in a color image, character bleeding may occur. On the other hand, the thermal transfer method has problems such as high running cost, low image fixability, and peeling of the ink layer.

In order to solve the above problems, for example, Japanese Patent Laid-Open No. 58-168057 discloses an image forming method in which an electrophotographic method for outputting a monochrome image and an ink jet method for outputting a color image are combined. A device has been proposed. Next, this image forming apparatus will be briefly described with reference to FIG.

The image forming apparatus shown in FIG. 1 has an electrophotographic image forming means I disposed on the upstream side (right side in the figure) of the apparatus main body M and a downstream side (left side in the figure). The whole is constructed by combining the provided image forming means II by the ink jet system.

The image forming means I forms a black and white image with toner on the recording material P by the photosensitive drum 1 as a photosensitive member and each process device and the like arranged around the photosensitive drum 1. First, a toner image is formed on the surface of the photosensitive drum 1 which is rotationally driven in the direction of arrow R1 by the primary charger 2, the exposure device 3, and the developing device 4. From the paper feed cassette 7, a paper feed roller 8, a conveyance guide 9, a registration roller 10, and a conveyance guide 1.
The recording material P is supplied to the photosensitive drum 1 via 1 or the like, and the toner image on the photosensitive drum 1 described above is
The image is transferred by the transfer charger 5. The recording material P after the transfer of the toner image is conveyed to the fixing device 13 along the conveyance guide 12, where the toner image on the surface is heated and pressed to be fixed, and the image of the black-and-white toner image by the image forming means I. The formation is complete. On the other hand, the photosensitive drum 1 after the toner image transfer
The transfer residual toner on the surface is removed by the cleaner 6.

The image forming means II has an ink jet recording section 25, by which ink is directly attached onto the recording material P after the toner image is fixed to form a color ink image. The recording material P on which the toner image is formed by the image forming unit I is conveyed along the conveyance guide 21 by the conveyance roller 22.
And the like, and is supplied to the inkjet recording unit 25. The inkjet recording unit 25 includes a recording head 25.
A color ink image is formed on the recording material P by ejecting ink from a nozzle array for three colors or four colors, which has a and an ink tank 25b.

The recording material P on which the black-and-white toner image and the color ink image are thus formed is discharged onto the paper discharge tray 30 by the paper discharge roller 24.

The above-mentioned image forming apparatus combining the electrophotographic method and the ink jet method is a single image forming apparatus, the size of the entire apparatus is minimized, and a black and white image is formed quickly and neatly, and is required. It is convenient that a color image can be formed according to the above.

In the image forming means I described above,
A corona charger is used as the primary charger 2. This corona charger has a shield member 2a having a U-shaped cross section and having an opening facing the surface of the photosensitive drum 1, and a corona wire 2b stretched near the opening. The corona wire 2b has a charging voltage of -2 to -4k.
A high negative voltage of V is applied, so that the surface of the photosensitive drum 1 is uniformly charged to a predetermined negative voltage. In addition to the primary charger 2, the transfer charger 5 also uses a corona charger having substantially the same configuration. However, a positive voltage is applied to this corona charger.

[0012]

However, according to the image forming apparatus having the above-mentioned configuration, the recording head 25a of the image forming means II and the recording head 25a of the image forming means II are used due to the influence of ozone generated from the primary charging device 2 and the transfer charging device 5. There is a risk that the ink may deteriorate and cause a malfunction of the recording head 25a and an image defect on the recording material P.

As shown in FIG. 7, the corona charger, which constitutes the primary charger 2 and the transfer charger 5, generates ozone during corona discharge. Although the ozone concentration varies depending on the applied voltage, for example, at the time of negative charging as in the above-described primary charging device 2, 10 ppm or more immediately below it, on the other hand, as in the transfer charging device 5 described above, positive charging is performed. Sometimes it reaches 1-2 ppm just below. These ozone are removed by using an ozone filter and a fan, and finally 0.1
It is reduced to ppm or less and is exhausted to the outside of the apparatus main body M.

However, ozone diffuses and convects in the apparatus main body M, and reaches the ink jet recording section 25 arranged in the same apparatus main body M as the recording material P is conveyed. As a result, the corrosion of the recording head 25a and the decolorization of the ink pigment are promoted, which causes malfunction and printing failure.

The ozone described above has substantially the same effect not only when the image forming means II is of the above-mentioned ink jet system but also when it is another system such as a thermal transfer system or a wire dot system. The influence of this ozone is caused by the electrophotographic image forming means I and the other image forming means.
This is a common problem in the above-described image forming apparatus that attempts to bring out the advantages of both types by combining II and II.

Therefore, the present invention provides an image forming apparatus which suppresses the generation of ozone in the electrophotographic system, thereby effectively taking advantage of the combination of the electrophotographic system and other systems. The purpose is.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an image provided with a plurality of image forming means including at least one image forming means for forming an image by an electrophotographic method. In the forming apparatus, an electrophotographic image forming unit includes a photoconductor, a charging unit that uniformly charges the surface of the photoconductor, an exposing unit that exposes the surface of the photoconductor to form an electrostatic latent image, and a static image. It has a developing means for forming a toner image by adhering toner to the latent image and a transferring means for transferring the toner image on the photoconductor onto a recording material, and the charging means is arranged in contact with the photoconductor. And a contact charging member to which a charging voltage is applied.

In this case, the contact charging member may be a rotatable roller member having a predetermined resistance value, or a brush member in which conductive fibers having a predetermined resistance value are implanted, or a predetermined resistance value. The blade member may be included.

A charge injection layer in which fine electrodes are dispersed may be provided on the surface of the above-mentioned photoconductor.

Next, in the image forming apparatus provided with a plurality of image forming means including at least one image forming means for forming an image by the electrophotographic method, the electrophotographic image forming means includes a photoconductor and a photoconductor. A charging unit that uniformly charges the surface, an exposing unit that exposes the surface of the photoconductor to form an electrostatic latent image, a developing unit that adheres toner to the electrostatic latent image to form a toner image, and a photoconductor. A transfer unit configured to transfer the above toner image onto a recording material, wherein the transfer unit includes a contact transfer member which is disposed in contact with the photosensitive member and to which a charging voltage is applied.

In this case, the transfer charging member is a rotatable roller member having a predetermined resistance value, or a brush member in which conductive fibers having a predetermined resistance value are implanted, or a predetermined resistance value is set. The blade member may be included.

Next, in an image forming apparatus having a plurality of image forming means including at least one image forming means for forming an image by an electrophotographic method, the electrophotographic image forming means comprises a photoconductor and a photosensitive material. Charging means for uniformly charging the body surface, exposing means for exposing the surface of the photoreceptor to form an electrostatic latent image, developing means for adhering toner to the electrostatic latent image to form a toner image, and photosensitive means A transfer means for transferring the toner image on the body onto the recording material, and the charging means described above,
It is characterized in that it has a proximity charging member which is arranged in non-contact with the surface of the photoconductor through a minute gap of 100 μm or less and to which a charging voltage is applied.

Finally, one of the plurality of image forming means may be an ink jet system in which the recording means ejects ink to perform recording. The recording means may include an electrothermal converter for generating thermal energy for ejecting ink, and the recording means uses the thermal energy applied by the electrothermal converter, The film may be ejected from the ejection port by utilizing the film boiling generated in the ink.

[0024]

According to the above construction, when the charging means has a contact charging member, the contact charging member is brought into contact with the photosensitive member,
Since the surface of the photoconductor is charged through the contact charging member brought into contact with it, it is possible to suppress the generation of ozone.

Even when the transfer means has a contact transfer member, the contact transfer member is brought into contact with the photosensitive member and the toner image is transferred through the contact transfer member brought into contact therewith, so that ozone is similarly generated. Can be suppressed.

Further, when the charging member has a proximity charging member, the proximity charging member is not in contact with the surface of the photoconductor but faces the surface of the photoconductor with a minute gap of 100 μm or less. Therefore, also in this case, the generation of ozone during charging can be reduced.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that in the following drawings, members and the like denoted by the same reference numerals indicate members and the like having the same configuration and function, and duplicate description thereof will be appropriately omitted. <Embodiment 1> FIG. 1 is an overall schematic configuration diagram of an image forming apparatus according to Embodiment 1. To explain the outline, the image forming apparatus shown in the figure has an electrophotographic image forming means I disposed on the upstream side (right side in the figure) of the apparatus main body M and the downstream side (left side in the figure). Inkjet image forming means
II, and the above-mentioned image forming means I has a contact charging member 2A arranged in contact with the photoconductor 1 as a charging means (primary charger). The upstream side and the downstream side of the apparatus main body M refer to the transport direction (direction of arrow K) of the recording material P that is an image forming target. The image forming apparatus of this embodiment can perform both ink jet recording and electrophotographic recording, that is, “composite” or “multiplex” recording on the same recording material. Here, the recording in which the ink image area of the inkjet recording and the toner image area of the electrophotographic recording do not overlap on the same recording material surface is referred to as “composite”, and the overlapping recording is referred to as “multiplex”.

The respective structures of the image forming means I and the image forming means II, the operation of the image forming apparatus as a whole, and the structure and operation of the contact charging member 2A will be described below in this order. In the present embodiment, a case will be described in which reversal development is performed using a negatively charged toner.

The electrophotographic image forming means I is a drum-shaped photosensitive member (hereinafter referred to as "photosensitive drum").
Has 1. The photosensitive drum 1 in this embodiment has a photosensitive layer made of an organic semiconductor (OPC) having a negative charging characteristic,
It is adapted to be rotationally driven in the direction of arrow R1. Around the photosensitive drum 1, almost in order along the rotation direction,
A contact charging member 2A as a primary charger (charging means) 2 for uniformly charging the surface of the photosensitive drum 1, an exposure device (exposure means) 3 for exposing the surface of the photosensitive drum 1 to form an electrostatic latent image, and a developing roller. A developing device (developing means) 4 for forming a toner image by attaching toner (developer) to the electrostatic latent image via 4a,
A transfer charger (transfer means) 5 for transferring the toner image on the photosensitive drum 1 onto the recording material P, and a cleaner 6 for removing the transfer residual toner on the surface of the photosensitive drum 1 are provided. Further, below the photosensitive drum 1, a conveyance path for the recording material P is formed. The transport path includes, in order from the upstream side, a paper feed cassette 7 that stores the recording material P, a paper feed roller 8 that feeds the recording material P from the paper feed cassette 7, a transport guide 9 that guides the transport of the recording material P, and a photosensitive member. A registration roller 10 that supplies the recording material P to the photosensitive drum 1 in synchronization with the rotation of the drum 1, and conveyance guides 11 and 1 that guide the conveyance of the recording material P before and after transfer.
2 etc. are arranged. A thermal fixing device (fixing unit) 13 is arranged on the most downstream side of the transport path. The heat fixing device 13 includes a heating roller 13 including a heater 13a _1.
a and a pressure roller 13b that comes into contact with the heating roller 13a from below.

The image forming means II includes a conveying guide 21 for guiding the recording material P discharged from the thermal fixing device 13, a conveying roller 22 for intermittently feeding the recording material P, and a recording material P for image printing from below. A platen 23 for supporting, a paper discharge roller 24 for discharging the recording material P after printing onto the paper discharge tray 30, and an inkjet recording unit 25 are provided. The inkjet recording unit 25 has a recording head 25a and an ink tank 25b, and is configured to eject ink of three to four colors toward the recording material P by a plurality of nozzle arrays provided in the recording head 25a. There is. A more specific structure of the recording head 25a will be described later.

Next, the operation of the entire image forming apparatus will be described. First, when a print signal is input to the image forming unit I, the photosensitive drum 1 is rotationally driven in the arrow R1 direction,
The surface of the charging roller 2A to which a negative charging voltage is applied is uniformly charged to a predetermined negative potential. An image area of the photosensitive drum 1 is irradiated with light by an exposure device 3 and negative charges in the light irradiation portion are removed, so-called image exposure is performed to form an electrostatic latent image on the surface. Subsequently, reversal development by the developing device 4 is performed. Developing device 4
The toner negatively charged by friction inside the developing roller 4a
It is carried and conveyed by the above, and is attached to the above-mentioned electrostatic latent image on the photosensitive drum 1, whereby a toner image is formed on the surface of the photosensitive drum 1. On the other hand, the recording material P fed from the paper feeding cassette 7 by the paper feeding roller 8 is recorded by the registration roller 1
0, the toner image is supplied to the photosensitive drum 1 at a predetermined timing, and the toner image on the photosensitive drum 1 is transferred to the supplied recording material P by the transfer charger 5.

The recording material P after the toner image transfer is subjected to heat and pressure when passing through the fixing nip portion between the heat roller 13a and the pressure roller 13b of the heat fixing device 13, and the toner on the surface is subjected to the heat and pressure. The image is fused and fixed and fixed. With the above, the formation of the black and white toner image by the electrophotographic image forming means I is completed.

The recording material P discharged from the heat fixing device 13 is
It is transported by the transport roller 22 along the transport guide 21 and is introduced below the inkjet recording unit 25.
In the recording head 25a of the inkjet recording unit 25, the above-mentioned plurality of nozzle arrays are electrically controlled, and the ejection of inks of three or four colors sufficient to form a color ink image is adjusted. Image formation (printing) on recording material P
Is the recording material P while the recording head 25a ejects ink.
This is achieved by the operation of moving the recording material P in the left-right direction in the traveling direction (arrow K direction) and the operation of the conveying roller 22 intermittently moving the recording material P in the conveying direction. As a result, a color ink image is formed on the recording material P.

In this way, the recording material P is formed with the black and white toner image by the electrophotographic image forming means I and the ink image by the ink jet type image forming means II, and the image formation is completed, and the paper is discharged. The sheet is discharged onto the sheet discharge tray 30 via the roller 24.

In the electrophotographic image forming means I described above, the contact charging member 2A is used as a primary charging device (charging means) for uniformly charging the photosensitive drum 1. As shown in FIG. 2, the contact charging member 2A is a rotatable roller member formed in a roller shape as a whole (hereinafter, referred to as “charging roller 2A”). Charging roller 2A
Is a core metal 2Aa arranged at the center, an elastic layer 2Ab surrounding the core metal 2Aa, and a resistance layer 2 covering the surface of the elastic layer 2Ab.
And Ac. The core metal 2Aa is made of metal or the like in a rod shape and is arranged along the generatrix of the surface of the photosensitive drum 1. The elastic layer 2Ab is made of synthetic rubber having appropriate elasticity, and has a resistance value of 10 by mixing conductive fine powder into the synthetic rubber.
It is adjusted to be ⁴ to 10 ⁸ Ω · cm. The resistance layer 2Ac is provided in order to prevent current from concentrating on a defective portion having a low resistance on the surface of the photosensitive drum 1, and has a resistance value of 1 due to the conductive fine powder.
It is formed of a synthetic resin adjusted to 0 ⁵ to 10 ⁹ Ω · cm. However, the resistance value of the resistance layer 2Ac is set to be higher than the resistance value of the elastic layer 2Ab. The charging roller 2A has an outer peripheral surface pressed against the surface of the photosensitive drum 1 by an urging member (not shown) that urges both ends of the core metal 2Aa toward the surface of the photosensitive drum 1, The charging nip portion N having an appropriate nip width is formed. A charging voltage is applied to the charging roller 2A, which charges the photosensitive drum 1. Core 2 of charging roller 2A
A direct current voltage or a superimposed voltage obtained by superimposing alternating current on a direct current is applied to Aa by a power source (not shown), whereby the charging roller 2A has a negative polarity on the surface of the photosensitive drum 1 via the elastic layer 2Ab and the resistance layer 2Ac. It is charged to a predetermined potential. The charging of the photosensitive drum 1 by the charging roller 2A is performed in the air between the minute gaps in the regions E on the upstream side and the downstream side of the charging nip N, as compared with the case where the charge is directly injected from the charging nip N. Discharge is dominant. The conventional corona charger has a large distance between the corona wire and the surface of the photosensitive drum 1, and a large amount of ozone is generated (10 ppm or more) because the corona discharge is generated over a wide area by applying a high voltage to perform charging. On the other hand, in the charging roller 2A of this embodiment, the amount of ozone generated is 0.02 to 0.02 by performing charging at a low voltage in the minute gap in the limited area E.
It could be reduced to 0.03 ppm. Therefore, it is possible to suppress the contamination of the recording head 25a of the image forming means II and the deterioration of the ink due to the ozone generated when the photosensitive drum 1 is charged.

In the above-mentioned embodiment, the corona charger is used as the transfer charger 5, but since the polarity of the transfer charger 5 at the time of toner image transfer is positive, the conventional primary charger having negative polarity is used. Less ozone is generated compared to 2. of course,
The transfer charger 5 can be changed from a corona charger to a contact transfer member.

As the contact transfer member of the transfer charger 5, a roller-shaped roller member (hereinafter referred to as "transfer roller") can be used as in the case of the primary charger. As a result, the amount of ozone generated is also 1 to 2 ppm of the conventional transfer amount.
Can be reduced to almost zero.

Contrary to the image exposure for exposing the image area described above, an electrostatic latent image is formed on the photosensitive drum 1 by exposing the non-image area. Considering the case of forming, since the development is performed with the toner of the positive polarity, which is the opposite of the image exposure, the transfer needs to be performed with the negative charge. In this case, the effect of changing the negative corona charger to a transfer roller which is a contact transfer member is very large as in the case of the primary charger 5, and the total ozone generation amount is suppressed to a low level. The contamination of 25a can be eliminated.

Further, in the above-mentioned embodiment, the roller-shaped roller member (charging roller, transfer roller) is used as the contact charging member and the contact transfer member.
It may be a blade member. The principle and effect of ozone generation reduction described for the roller member are the same for these brush members and blade members. That is, for example, a fixed brush member or a movable brush member that rotates is used, which is configured by implanting conductive fibers on a substrate, and the tip of the conductive fibers is brought into contact with the surface of the photosensitive drum 1 to charge the surface. Even when it is performed, the discharge that contributes to the charging is performed in a minute area near the tip of the conductive fiber and the surface of the photosensitive drum 1. Further, even when a conductive blade member is brought into contact with the surface of the photosensitive drum 1, the charging is performed by the discharge of a minute area in the vicinity of the contact portion.

In the image forming apparatus having the above-mentioned structure, ozone generated at the time of charging or transferring is diffused almost all over the apparatus main body M, so that the arrangement positions of the charging means and the transfer means are changed, Image forming means I and image forming means
It is difficult to avoid the ozone problem by reversing the upstream and downstream positions of II. Therefore, in the image forming apparatus having the electrophotographic image forming means I in one of the plurality of image forming means,
The method of suppressing the generation of ozone itself as in the present embodiment is very effective in that ozone does not adversely affect other image forming means (for example, the image forming means II of the inkjet system).

The present invention is effective regardless of whether the electrophotographic image forming means I is on the upstream side or the downstream side of the other image forming means. Considering that ozone easily moves, it is particularly remarkable when the electrophotographic image forming means I is arranged on the upstream side and another image forming means is arranged on the downstream side as described above. Has a great effect. <Embodiment 2> FIG. 3 is an overall schematic configuration diagram of an image forming apparatus according to Embodiment 2. In the image forming apparatus shown in the figure, the photosensitive drum 1A has a photosensitive layer having a positive charging characteristic.
The primary charger 2 includes a shield 2a and a corona wire 2
b is a corona discharger having positive polarity, the photosensitive drum 1 is positively charged, the developing device 4A performs reverse development with toner positively charged by friction, and the transfer charger 5A is a roller as a contact transfer member. A member (hereinafter referred to as “transfer roller”), which is configured to transfer a toner image by applying a negative transfer voltage. The other configurations are similar to those of the first embodiment.

Next, the operation of the image forming apparatus having the above configuration will be described. The photosensitive drum 1A whose surface is positively charged by the primary charger 2 is image-exposed by the exposure device 3, and an electrostatic latent image is formed on the photosensitive drum 1A by removing the positive charges in the image portion of the image data. It The electrostatic latent image on the photosensitive drum 1A is reverse-developed with positive polarity toner and visualized as a toner image. The toner image on the photosensitive drum 1A is electrostatically transferred onto the recording material P by the transfer roller 5A. The subsequent operation is similar to that of the first embodiment.

In the image forming apparatus having the above-described structure, the transfer charging of the negative polarity which is likely to generate ozone in the image forming means I is transferred by the rotatable transfer roller 5A instead of the conventional corona transfer. Therefore, ozone generation can be significantly suppressed. This is because, as in the case of the charging roller 2A of Example 1, the discharge at the time of transfer can be limited to a minute area and the applied voltage can be lowered.
In fact, the ozone generated by 10 ppm or more in the conventional corona charger is reduced to 0.02 to 0.03 ppm by the contact transfer by the transfer roller 5A. Therefore,
It is possible to reduce malfunction of the recording head 25a of the image forming means II and prevent ink deterioration.

In the second embodiment described above, image formation may be performed by background exposure. In this case, the transfer charge becomes positive polarity, and when the positive polarity corona charge is 1 to
What generated 2 ppm of ozone was the transfer roller 5
By using A, it can be reduced to almost 0 and contamination of the recording head 25a can be prevented.

In the second embodiment, the corona charger 2 is used because the primary charger has a positive polarity, but of course, instead of this, the charging roller 2A as described in the first embodiment is used.
May be applied. That is, also in the case of primary charging, by performing contact charging with the charging roller 2A, the amount of ozone generated can be reduced from almost 1 to 2 ppm in the past to almost zero, and the total amount of ozone generated is extremely high. It becomes a very small amount.

Further, as the contact transfer member, other than the transfer roller 5A, a brush member or a blade member may be used as in the case of the contact charging member of the first embodiment. <Embodiment 3> FIG. 4 shows a vertical sectional view of a photosensitive drum 1B having a charge injection layer 1a. The charge injection layer 1a is newly provided in the uppermost layer of the photoconductor to hold the charge, and the charge is directly injected and charged from the charging member contacting and contacting. Therefore, almost no ozone is generated. The charge injection layer 1a is formed by dispersing conductive fine particles as microelectrodes in a synthetic resin and coating it on the uppermost layer of the photoconductor. As the contact charging member, for example, the conductive fiber 2 is formed on the base 2Ba.
Using a charging brush (brush member) 2B in which Bb is planted,
The conductive fibers 2Bb are evenly contacted throughout the direction of the generatrix of the charge injection layer 1a, thereby directly injecting charges and charging.

The charge injection layer 1a is formed on the photosensitive drum 4a.
The image bearing member provided with is charged by the charging brush 2B in which the conductive fibers 2Bb are bundled. The third embodiment is the same in that the charging member is in contact with the photosensitive drum 1B, but in the third embodiment, the electric charge is directly injected into the charge injection layer 1a, so that the air discharge is performed. Ozone generation due to is further reduced as compared with the case of the first embodiment, and the effect on the contamination of the recording head 25a is very large.

Further, when the charging brush 2B is configured as a rotatable roller, charging can be performed more efficiently.

Further, although the third embodiment has been described with respect to the negative photosensitive drum 1 of the first embodiment, the corona charging is also performed when the primary photosensitive ozone is reduced by the positive photosensitive drum 1A of the second embodiment. It can also be applied instead of, and is effective in reducing ozone. In this case, the configuration and operation of the other devices except the contact charging member are the same as those in the second embodiment. <Embodiment 4> In Embodiments 1 and 2 described above, ozone generation is suppressed by contact charging (primary charging, transfer charging), but instead of this, the charging member is not in contact, and the photosensitive drum 1 By arranging in close proximity to the surface and causing discharge in a limited minute area as in the first and second embodiments, it is possible to reduce the ozone generation amount compared to the corona charger using a wire.

5 and 6 show the negative photosensitive drum 1 of the image forming apparatus and the proximity charging member 2C having a concave charging surface 2Ca.
And a spacer 2 for holding a minute gap G between them.
And Cb. The configuration of the entire device is in accordance with the first embodiment. Even if the proximity charging member 2C is not in contact with the photosensitive drum 1,
With the spacer 2Cb, the proximity charging member 2C having a conductive layer is separated from the surface of the photosensitive drum 1 by a minute gap G of 100 μm or less.
Is maintained so as to ensure the above, and by applying a direct current or a voltage in which a direct current and an alternating current are superimposed on this proximity charging member 2C, it is possible to generate an air discharge in the minute gap G and perform charging. As a result, the amount of ozone generated is reduced as compared with the corona charger, and the contamination of the recording head 25a can be reduced.

In the fourth embodiment, the case of the negative photosensitive drum 1 of the first embodiment is shown, but when the positive photosensitive drum 1A of the second embodiment reduces the ozone of the primary charge, corona charging is also performed. It can be applied instead and is effective in reducing ozone. The configuration and operation of the apparatus in this case is the same as the second embodiment.
Follow

Next, the recording head 25a of the ink jet recording section 25 of the second image forming means II will be described in more detail.

The present invention provides excellent effects particularly in a recording apparatus using an inkjet recording head 25a for recording by forming flying droplets by utilizing thermal energy among the inkjet recording systems. .

With regard to its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored, a rapid temperature rise corresponding to the recorded information and exceeding nucleate boiling is applied. Since heat energy is generated in the electrothermal converter to cause film boiling on the heat acting surface of the recording head 25a, air bubbles in the liquid (ink) corresponding to this drive signal in a one-to-one correspondence can be formed. It is valid.
The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, US Pat. No. 4,463,359 is used.
Nos. 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head 25a, a combination constitution of a discharge port, a liquid passage and an electrothermal converter as disclosed in the above-mentioned respective specifications (a straight liquid passage or a right-angled liquid passage).
US Pat. Nos. 4,558,333 and 44, which disclose a configuration in which a heat acting portion is arranged in a bending region in addition to the above.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the structure corresponding to the discharging portion is disclosed in Japanese Patent Laid-Open No. 59-138461. That is, regardless of the form of the recording head 25a, according to the present invention, recording can be reliably and efficiently performed.

Further, the present invention can be effectively applied to the full-line type recording head 25a having a length corresponding to the maximum width of the recording medium which can be recorded by the recording apparatus. As such a recording head 25a, a plurality of recording heads 2
Either a configuration that satisfies the length by the combination of 5a or a configuration as one recording head 25a integrally formed may be used.

In addition, even in the case of the serial type as in the above example, the recording head 25a fixed to the main body of the apparatus or the ink from the main body of the apparatus is electrically connected to the main body of the apparatus by being mounted on the main body of the apparatus. The present invention is also effective when a replaceable chip type recording head 25a capable of supplying the ink is used or a cartridge type recording head 25a in which an ink tank is integrally provided in the recording head 25a itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add an ejection recovery means for the recording head 25a, a preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specific examples of these are: preliminary heating for the recording head 25a by using capping means, cleaning means, pressurizing or suctioning means, electrothermal converters or other heating elements or combinations thereof. Examples include a heating unit and a preliminary ejection unit that performs ejection different from recording.

Regarding the type or number of the recording heads 25a to be mounted, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head 35a may be integrally configured or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of recording modes of full-color by color or mixed colors.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or below and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or to prevent the ink from evaporating, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, the ink is liquefied by applying heat energy according to the recording signal,
The present invention is also applicable to the case of using an ink that has a property of liquefying only when heat energy is applied, such as one that ejects liquid ink or one that already begins to solidify when it reaches a recording medium. In such a case, the ink is retained as a liquid or solid in the recesses or through holes of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the ink jet recording apparatus of the present invention, in addition to the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function can be used. It may be a form or the like.

[0062]

As described above, according to the present invention,
Since the generation of ozone can be suppressed by charging or transferring the photoconductor with the contact charging member or the contact transfer member, the electrophotographic image forming means and the image forming means of other methods can be used. It is possible to effectively take advantage of the combination.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a vertical cross-sectional view showing the configuration of a charging roller of Example 1.

FIG. 3 is an overall schematic configuration diagram of an image forming apparatus according to a second embodiment.

FIG. 4 is a vertical cross-sectional view showing a configuration of a photosensitive drum having a charge injection layer and a charging brush of Example 3.

FIG. 5 is a vertical cross-sectional view showing the configuration of a charging blade of Example 4.

FIG. 6 is a front view showing a minute gap formed between a photosensitive drum and a charging blade of Example 4.

FIG. 7 is an overall schematic configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

I First Image Forming Means (Electrophotographic Method) II Second Image Forming Means (Inkjet Method) 1, 1A, 1B Photoreceptor (Photosensitive Drum) 2 Charging Means (Primary Charger) 2A Contact Charging Member (Charging Roller) 2B Contact charging member (charging brush) 2C Contact charging member (charging blade) 3 Exposure means (exposure device) 4, 4A Developing means (developing device) 5, 5A Transfer means (transfer charging device) 6 Cleaner 7 Paper cassette 8 Supply Paper roller 10 Registration roller 13 Fixing means (heat fixing device) 13a Heating roller 13b Pressure roller 23 Platen 24 Paper discharge roller 25 Ink jet recording section 25a Recording means (recording head) 25B Ink tank G Micro gap M Device body P Recording medium ( Recording material)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yukihide Ushio 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Izumi Narita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazunori Hira 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naohiro Nakane 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji Muto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Person Noboru Yukimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (13)

[Claims] 1. An image forming apparatus comprising a plurality of image forming means including at least one image forming means for forming an image by an electrophotographic method, wherein the electrophotographic image forming means comprises a photoconductor and a photosensitive member. Charging means for uniformly charging the surface of the body, exposing means for exposing the surface of the photoreceptor to form an electrostatic latent image, and developing means for forming a toner image by attaching toner to the electrostatic latent image. A transfer unit configured to transfer the toner image on the photoconductor onto a recording material, and the charging unit includes a contact charging member which is disposed in contact with the photoconductor and to which a charging voltage is applied. A characteristic image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the contact charging member is a rotatable roller member having a predetermined resistance value. 3. The image forming apparatus according to claim 1, wherein the contact charging member is a brush member in which conductive fibers having a predetermined resistance value are implanted. 4. The image forming apparatus according to claim 1, wherein the contact charging member is a blade member having a predetermined resistance value. 5. The image forming apparatus according to claim 1, wherein a charge injection layer in which fine electrodes are dispersed is provided on the surface of the photoconductor. 6. An image forming apparatus comprising a plurality of image forming means including at least one image forming means for forming an image by an electrophotographic method, wherein the electrophotographic image forming means comprises a photoconductor and a photosensitive member. Charging means for uniformly charging the surface of the body, exposing means for exposing the surface of the photoreceptor to form an electrostatic latent image, and developing means for forming a toner image by attaching toner to the electrostatic latent image. A transfer unit configured to transfer the toner image on the photosensitive member onto a recording material, the transfer unit including a contact transfer member disposed in contact with the photosensitive member and to which a charging voltage is applied. A characteristic image forming apparatus. 7. The image forming apparatus according to claim 6, wherein the contact transfer member is a rotatable roller member having a predetermined resistance value. 8. The image forming apparatus according to claim 6, wherein the contact transfer member is a brush member in which conductive fibers having a predetermined resistance value are implanted. 9. The image forming apparatus according to claim 6, wherein the contact transfer member is a blade member having a predetermined resistance value. 10. An image forming apparatus comprising a plurality of image forming means including at least one image forming means for forming an image by an electrophotographic method, wherein the electrophotographic image forming means comprises a photoconductor and the photosensitive material. Charging means for uniformly charging the surface of the body, exposing means for exposing the surface of the photoreceptor to form an electrostatic latent image, and developing means for forming a toner image by attaching toner to the electrostatic latent image. A transfer means for transferring the toner image on the photoconductor onto a recording material, the charging means being disposed in non-contact with the surface of the photoconductor through a minute gap of 100 μm or less and a charging voltage. An image forming apparatus having a proximity charging member to which is applied. 11. The image according to claim 1, wherein one of the plurality of image forming units is an ink jet system in which the recording unit ejects ink to perform recording. Forming equipment. 12. The image forming apparatus according to claim 11, wherein the recording unit includes an electrothermal converter for generating thermal energy for ejecting ink. 13. The ink jetting apparatus according to claim 12, wherein the recording unit ejects the ink from the ejection port by utilizing the film boiling generated in the ink by the thermal energy applied by the electrothermal converter. Image forming apparatus.