JPH04254882A - Picture image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of toner image turbulance without using an AC corona discharger when a body to be developed in which a toner image is formed is separated from an electrostatic latent image carrier. CONSTITUTION:A record supporting body 114 is made to contact a body to be developed 102 on the downstream side from a developing process and also on the upstream side from a part where the said body to be developed 102 is separated from an electrostatic latent image carrier 101 in the feed direction of the body to be developed 102. A contact condition between the said record supporting body 114 and the body to be developed 102 is kept in a space between the contact point of the said record supporting body 114 and the body to be developed 102 to a transcription process. Consequently the body to be developed 102 in which a toner image is formed is separated from the electrostatic latent image carrier 101 after developing, but the body to be developed 102 is covered with the record supporting body 114, eliminating the dispersion of toner 108 even if aerial discharge occurres due to the reduction of the electrostatic capacity of a pneumatic layer 120 between the body to be developed 102 and the electrostatic latent image carrier 101.

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 used in recording devices and display devices such as printers and copying machines.

0002

[Prior Art] Conventionally, in image forming apparatuses used in printers and copying machines, the electrophotographic recording method using the Carlson method has generally been used because of its fast recording speed, high image quality, and ability to record on plain paper. Adopted (U.S.P. 2, 297, 691 (1941)
reference).

In this method, the photoreceptor is subjected to charging, exposure, and development processes to form a toner image. Then, a recording medium is superimposed on the toner image on the photoreceptor and transferred, and then the toner image transferred onto the recording medium is fixed. Further, in order to repeatedly use the photoreceptor, a cleaning process is provided to remove powder toner remaining on the photoreceptor after transfer.

[0004] That is, the electrophotographic recording method using the Carlson method is constituted by the six basic processes described above. However, in the electrophotographic recording method using the Carlson method described above, in the transfer process, toner is transferred to the recording medium using electrostatic force (electrostatic transfer), but due to poor transfer efficiency, it is necessary to clean the photoreceptor surface after transfer. A cleaning process is required. Additionally, maintenance work is required to dispose of the collected residual toner, which poses problems such as contaminating the operator's body and clothing and scattering the toner inside and outside the device.

Therefore, instead of directly forming a toner image on the electrostatic latent image bearing member, a toner image is formed on the developing member by closely contacting the developing object with the electrostatic latent image bearing member. An image forming apparatus that simultaneously performs fixing and eliminates the need for a cleaning device has been provided (see Japanese Patent Laid-Open No. 2-197884). FIG. 2 is a schematic diagram of a conventional image forming apparatus.

In the figure, reference numeral 101 is an electrostatic latent image carrier formed in the shape of a drum, and a photoconductive layer is provided on a conductive support. Reference numeral 102 denotes an endless member to be developed, which is stretched between the electrostatic latent image carrier 101 and the pressure roll 103 . 104 is a charging device as a charging means, which is provided facing the surface of the electrostatic latent image carrier 101;
is an exposure device serving as an exposure means, which converts an image signal into light and irradiates the electrostatic latent image carrier 101 with the light.

A developing device 106 serves as a developing means, which attracts toner 108 onto a toner carrier 107 and transports it in the direction of arrow A in the figure.
A developing object 102 closely stacked so as to cover the electrostatic latent image formed on 01 is developed. 110 is a heat generating roll provided in pressure contact with the pressure roll 103. The heating roll 110 includes a hollow sleeve and a heating lamp inside the sleeve.
For example, it is formed by providing a halogen lamp or the like.

Next, the operation and function of the image forming apparatus having the above configuration will be explained. When the electrostatic latent image carrier 101 rotates at a constant circumferential speed in the direction of arrow B in the figure by a driving means (not shown), the object to be developed 102 moves in the direction of arrow C in the figure due to the frictional force with the electrostatic latent image carrier 101. . First, in the charging process, the electrostatic latent image carrier 101 is uniformly and evenly charged by the charging device 104. Between this charging process and the developing process described later, the object to be developed 102 is placed in close contact with the electrostatic latent image carrier 101.

Next, in the exposure process, the exposure device 105
As a result, light corresponding to the image signal is transmitted through the object to be developed 102 and irradiated onto the electrostatic latent image carrier 101, thereby forming an electrostatic latent image. In the developing process, the object to be developed 10 is closely stacked on the electrostatic latent image carrier 101 by the developing device 106.
2 is developed. That is, the toner carrier 107
The charged toner 108 on the top adheres to the object to be developed 102 by electrostatic force and is developed, forming a toner image.

Thereafter, the object to be developed 102 separated from the electrostatic latent image carrier 101 is transferred to a pressure roll 103 and a heating roll 1.
The image is conveyed to a transfer/fixing section consisting of 10. and,
The object to be developed 102 on which the toner image has been formed and the recording paper 114 are overlapped here and heated and pressurized. Heat generating roll 110
The heat is transmitted to the toner 108 on the object to be developed 102 via the recording paper 114 and melts it. fused toner 10
8 is infiltrated between the fibers of the recording paper 114 by pressure action, and transfer and fixation to the recording paper 114 are performed simultaneously.

The transferred and fixed recording paper 114 is delivered to the outside of the apparatus by a paper delivery roll 117. On the other hand, after the electrostatic latent image carrier 101 is separated from the object to be developed 102 after the development process, the entire surface of the electrostatic latent image carrier 101 is irradiated with light by an optical charge eliminating lamp 119 serving as a charge eliminating means to remove residual charges on the surface. In this way, the electrostatic latent image carrier 101 is used repeatedly.

Incidentally, the toner 108 may remain on the developing object 102 after being transferred to the recording paper 114. However, the amount of residual toner in this case is extremely small, and moreover, it is not a powder that easily scatters as in the conventional example. That is, the toner 108 is melted by the heating effect of the transfer process and is fixed to the object to be developed 102, so that it does not easily scatter. Moreover, this residual toner can be wiped off by a fixing cleaner 118 constituted by a cleaning pad such as felt while it is in the molten state. Therefore, when the toner 108 is disposed of, the operator's body and clothes are not soiled, and the toner 108 is not scattered inside or outside the apparatus, resulting in improved maintainability. Moreover, powdered toner 10
8 cleaning equipment is not required, the number of processes is reduced from 6 to 4, and the cost of the equipment can be reduced.

However, in the image forming apparatus having the above configuration, toner scattering may occur around the characters, etc. of the image formed on the recording paper 114, resulting in blurring, and it is difficult to obtain sufficiently stable image quality. I can't. When this toner scattering is investigated, it is found that the electrostatic latent image bearing member 101 and the developing object 102
It can be seen that this occurs when the two are separated. Therefore, a method has been proposed to prevent this (see Japanese Patent Application No. 1-270204).

FIG. 3 is a schematic diagram of an image forming apparatus in which images are not blurred. In the figure, reference numeral 109 denotes an AC corona charger, which is provided at any part of the range from the part where the electrostatic latent image carrier 101 and the object to be developed 102 are in close contact to the part where they are separated. Eliminates static electricity. The cause of toner scattering is that the object to be developed 102 is the electrostatic latent image carrier 10.
1, the air layer between them expands, and as the capacitance decreases, the potential difference between the air layers increases and discharge occurs. The AC corona charger 109 removes charges on the surface of the object to be developed 102 to prevent discharge during separation. This prevents scattering and disturbance of the toner image on the object to be developed 102 during separation, and prevents the image from becoming blurred.

[0015]

However, in the conventional image forming apparatus described above, the voltage applied to the AC corona charger 109 must be several KV in order to remove the charge on the surface of the object to be developed 102. First, an expensive AC high voltage power source is required. The present invention solves the problems of the conventional image forming apparatus described above, and uses an AC corona discharger to prevent scattering and disturbance of the toner image when the object to be developed separates from the electrostatic latent image carrier. It is an object of the present invention to provide an image forming apparatus that can prevent the problem from occurring without using it.

[0016]

[Means for Solving the Problems] To achieve this, in the image forming apparatus of the present invention, the electrostatic latent image carrier and the object to be developed are partially brought into contact, the electrostatic latent image carrier is charged, and exposed to light. As a result, an electrostatic latent image is formed. A to-be-developed object is placed in close contact with the electrostatic latent image carrier on which the electrostatic latent image is formed, and a developing device forms a toner image on the to-be-developed object. Then, the object to be developed on which the toner image is formed is placed on the recording support, and a transfer device transfers the toner image onto the recording support.

In the feeding direction of the developing object, the recording support is located downstream of the developing process and upstream of the part where the developing object separates from the electrostatic latent image carrier. be brought into contact with. The contact state between the recording support and the object to be developed is maintained from the point of contact between the recording support and the object to be developed until the transfer process.

[0018]

[Operation] According to the present invention, as described above, in the feeding direction of the object to be developed, the area is downstream of the developing process and upstream of the part where the object to be developed is separated from the electrostatic latent image carrier. , the recording support is brought into contact with an object to be developed. The contact state between the recording support and the object to be developed is maintained from the point of contact between the recording support and the object to be developed until the transfer process.

Therefore, the object to be developed on which the toner image is formed is separated from the electrostatic latent image carrier after development. At this time, even if the potential of the air layer increases as the capacity of the air layer between the object to be developed and the electrostatic latent image carrier decreases, and an air discharge occurs,
Since the object to be developed is covered with the recording support, the toner image will not be scattered or disturbed.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus showing a first embodiment of the present invention. In the figure, 1
01 is an electrostatic latent image carrier formed in a drum shape,
A photoconductive layer 101b is provided on a conductive support 101a, and includes a selenium photoreceptor, an organic photoreceptor, a zinc oxide photoreceptor,
Any material such as an amorphous silicon photoreceptor can be used. In this embodiment, a positively charged photoreceptor is used in which a charge transport layer and a charge generation layer are sequentially laminated as a photoconductive layer 101b on a conductive support 101a. The electrostatic latent image carrier 101 is rotated at a constant circumferential speed in the direction of arrow D in the figure by a motor (not shown).

Reference numeral 102 denotes an endless body to be developed, which includes an electrostatic latent image carrier 101, a pressure roll 103, and a tension roll 11.
It is strung between 1. The object to be developed 102 is made of a polyimide base material coated with a fluororesin. Reference numeral 104 denotes a charging device as a charging means, which is provided facing the surface of the electrostatic latent image carrier 101. A corona charger as shown in the figure is generally used, but in addition to this, a brush charger etc. can also be used.

Reference numeral 105 denotes an exposure device as an exposure means, which converts an image signal into light and irradiates the electrostatic latent image carrier 101 with the light. For the exposure device 105, any device such as a combination of an LED array and SELFOC lens (trade name), a combination of a laser and an imaging optical system, etc. can be used. 106 is a developing device as a developing means, which attracts the toner 108 onto the toner carrier 107 and conveys it in the direction of the arrow E in the figure.
Development is performed on a developing object 102 which is closely stacked so as to cover the electrostatic latent image formed on the developing object 102. Furthermore, for the developing device 106, any technology such as a two-component magnetic brush developing device, a one-component magnetic brush developing device, a one-component non-magnetic developing device, etc. can be used.

Reference numeral 110 denotes a heat-generating roll provided in pressure contact with the pressure roll 103, and the heat-generating roll 110 is constructed by providing a heat-generating lamp, such as a halogen lamp, inside a hollow sleeve. In addition, it is also possible to use a roller having a heating element on the surface of the roll. Next, the operation and effect of the image forming apparatus will be explained.

When the electrostatic latent image carrier 101 rotates at a constant circumferential speed in the direction of arrow D in the figure by a driving means (not shown), the object to be developed 102 rotates in the direction of arrow F in the figure due to the frictional force with the electrostatic latent image carrier 101. Move to. The tension roll 111 is equipped with a tension mechanism (not shown), and the tension roll 111 is equipped with a tension mechanism (not shown).
02, the object to be developed 102 moves at the same speed as the electrostatic latent image carrier 101.

The image forming process will now be described with reference to FIG. FIG. 4 is a diagram showing the image forming process of the image forming apparatus of the present invention, (A) is a diagram showing the charging process, (B) is a diagram showing the exposure process, (C) is a diagram showing the developing process, ( D) is a diagram showing the transfer/fixing process. First, the charging device 104 uniformly and uniformly charges the electrostatic latent image carrier 101 on which the photoconductive layer 101b is formed (A). The figure shows an example using a plus type photoconductor.
A positive polar charge is formed on the surface.

In the exposure process, light corresponding to an image signal is transmitted through the developing object 102 and irradiated onto the electrostatic latent image carrier 101 by the exposure device 105, thereby forming an electrostatic latent image (B). The object to be developed 102 may be configured to be in close contact with the electrostatic latent image carrier 101 between the charging process and the development process. The structure is such that the latent image carrier 101 is in close contact.

In the development process, the electrostatic latent image carrier 101
Development is performed by a developing device 106 (see FIG. 1) provided in contact with the object 102 to be developed (C).
. In this embodiment, reversal development is performed, and the electrostatic latent image carrier 10
1, the conductive support 101a, and the toner carrier 107, a bias potential applying means 112 is provided to apply a bias potential. With this configuration, in the space between the toner carrier 107 and the object to be developed 102, lines of electric force accompanying the electrostatic latent image formed on the electrostatic latent image carrier 101 through the object to be developed 102 are generated. Occur. Therefore, the charged toner 108 on the toner carrier 107 is transferred to the object to be developed by electrostatic force.
02 and is developed to form a toner image.

A photostatic discharge lamp 119 is provided downstream of the developing device 106, and the light generated from the optical discharge lamp 119 passes through the body 102 from above the body 102 to form an electrostatic latent image. The carrier 101 is irradiated to remove the charge on it. On the other hand, as a toner image is formed on the object to be developed 102, a recording support (generally paper is used), that is, a recording paper 114 is fed from a paper feeding means (not shown).
is taken out and sent to paper feed roll 116. At this stage, the paper feed roll 116 has stopped, but the object to be developed 10
A recording paper 11 is placed at the leading edge of the recording portion of the toner image formed on 2.
4 is controlled and activated so that they match. Recording paper 114
As shown in the figure, the object to be developed 1 is placed on the electrostatic latent image carrier 101.
02 is in close contact with the object 1 to be developed, and furthermore, on the downstream side of the development process and upstream of the part where the object 102 is separated from the electrostatic latent image carrier 101, the object 1 to be developed has a toner image formed thereon.
It contacts 02 and is superimposed on it. Here, recording paper 11
4 is attracted to the object to be developed 102 by the action of static electricity,
It is conveyed together with this and guided to a transfer/fixing section via a separating section between the object to be developed 102 and the electrostatic latent image carrier 101.

Next, the object to be developed 102 is the electrostatic latent image carrier 1
01 will be explained using FIGS. 5 and 6 together. FIG. 5 is an explanatory diagram of a separated state of a developing object in a conventional image forming apparatus, and FIG. 6 is an explanatory diagram of a separated state of a developing object in an image forming apparatus of the present invention. In the case of FIG. 5, as the object to be developed 102 and the electrostatic latent image carrier 101 are separated, the air layer 120 between them expands, and the capacitance of the air layer 120 decreases. Therefore, the potential difference between the air layers 120 increases and discharge occurs, whereby the toner 108 on the object to be developed 102 is scattered under the action of Coulomb force.

On the other hand, in the case of FIG. 6, since the recording paper 114 is adsorbed onto the toner image formed on the toner image to be developed 102, the force acting on the toner 108 due to the discharge generated when the toner image is separated is absorbed by the recording paper. 114, it is possible to prevent scattering and disturbance of the toner image. Thereafter, the developing object 102 separated from the electrostatic latent image carrier 101 is transferred to the recording paper 1.
14 and is conveyed to a transfer/fixing section composed of a pressure roll 103 and a heating roll 110. Then, the object to be developed 102 on which the toner image is formed and the recording paper 114 are heated and pressurized here.

At this time, the heat from the heating roll 110 is applied to the recording paper 1.
The toner 108 on the object to be developed 102 is melted through the toner 14, and the toner 108 penetrates between the fibers of the recording paper 114 due to the pressure action, so that the toner 108 is transferred to the recording paper 114 and fixed at the same time (D). The transferred and fixed recording paper 114 is sent out to the outside of the image forming apparatus by a paper delivery roll 117.

On the other hand, a small amount of toner 108 may remain on the developing object 102 after transfer and fixing, but if a polyimide base material coated with fluororesin is used as the developing object 102, Toner 10
No. 8 has good mold releasability and leaves almost no residue. On the other hand, after the development process and before the electrostatic latent image carrier 101 is separated from the object to be developed 102, the entire surface of the electrostatic latent image carrier 101 is irradiated with light by a photostatic discharge lamp 119 serving as a charge eliminating means. Residual charge is removed. In this way, the electrostatic latent image carrier 10
1 is used repeatedly.

The object to be developed 102 used here is heated by a heating roll 110 during the transfer/fixing process,
It reaches around 0°C. Therefore, the material needs to have a certain degree of heat resistance and insulation. Considering these,
Films made of materials such as polyester, polyimide, polyetherimide, polyether sulfone, and polyether ether ketone can be used. Furthermore, considering the electric lines of force generated between the object to be developed 102 and the toner carrier 107 during development, the thickness of the film is 100 μm.
Below, and considering the tensile strength and handleability, 5μ
It is desirable to set it to m or more.

Furthermore, in this embodiment, the object to be developed 102 is superimposed on the electrostatic latent image carrier 101 between the exposure process and the development process, and light is directly irradiated onto the electrostatic latent image carrier 101 in the exposure process. After forming an electrostatic latent image, the object to be developed 102 is closely overlapped with the electrostatic latent image carrier 101 before the development process. However, between the charging process and the exposure process, the object to be developed 102 is transferred to the electrostatic latent image carrier 1.
Exactly the same effect can be expected even if the electrostatic latent image carrier 101 is closely contacted with the electrostatic latent image carrier 101 and the light is transmitted through the developing object 102 and irradiated onto the electrostatic latent image carrier 101 in the exposure process. In this case, the object to be developed 102 needs to have a property of being transparent to the emission wavelength of the light source used in the exposure means.

FIG. 7 is a schematic diagram of an image forming apparatus showing a second embodiment of the present invention. As shown in the figure, recording paper 1
The lower surface side of 14 is overlapped with the object to be developed 102 . This allows the recording sheets 114 to be stacked face down. A pinch roll 130 is provided at a contact portion where the recording paper 114 and the developing object 102 superimposed on the electrostatic latent image carrier 101 are overlapped, and the recording paper 114 is brought into close contact with the developing object 102 here.

The heating body 140 in the transfer section is a resistor made of Ni--P or the like and having a length corresponding to the width of the recording paper 114 and is in the form of a band on a base material such as glass, enamel, or ceramic. Laminated, and then Ta2-O
5. It is constructed by laminating protective layers such as fluorine. When a current is passed through this resistor, the toner 1 on the object to be developed 102
08 and the recording paper 114 are heated while being pressed by a pressure roll 145, and the toner 108 is transferred to the recording paper 114 and fixed at the same time.

[0037] Also, a conductive roll 150 is used as a charging means.
is used to charge the surface of the electrostatic latent image carrier 101. Therefore, in this embodiment, since no corona charger is used, almost no ozone is generated. Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

For example, in the above embodiment, an endless-shaped object is used as the object to be developed 102.
The object to be developed 102 having an end portion and wound around a supply roll may be sent out to a take-up roll. Further, in the above embodiment, the toner image on the object to be developed 102 is transferred to the recording paper 114 by heating and applying pressure, but an electrostatic transfer method may be adopted.

[0039]

As explained in detail above, according to the present invention, the object to be developed is located downstream of the developing process in the feeding direction of the object to be developed, and the object to be developed is separated from the electrostatic latent image carrier. The recording support is brought into contact with the object to be developed on the upstream side of the portion where the recording medium is exposed. The contact state between the recording support and the object to be developed is maintained from the point of contact between the recording support and the object to be developed until the transfer process.

The object to be developed on which the toner image has been formed is separated from the electrostatic latent image carrier after development, but at this time, the object to be developed is covered with the recording support. Therefore, even if an air discharge occurs due to an increase in the potential of the air layer as the capacity of the air layer between the developing object and the electrostatic latent image carrier decreases, the toner will not be scattered, and the toner will not be scattered. The image is not disturbed and the printing quality can be improved.

Moreover, since toner scattering can be prevented without using an AC corona charger, it is possible not only to reduce costs but also to suppress the generation of ozone.

[Brief explanation of the drawing]

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

FIG. 2 is a schematic diagram of a conventional image forming apparatus.

FIG. 3 is a schematic diagram of an image forming apparatus in which images are not blurred.

FIG. 4 is a diagram showing an image forming process of the image forming apparatus of the present invention.

FIG. 5 is an explanatory diagram of a separated state of a developing object in a conventional image forming apparatus.

FIG. 6 is an explanatory diagram of a separated state of the object to be developed in the image forming apparatus of the present invention.

FIG. 7 is a schematic configuration diagram of an image forming apparatus showing a second embodiment of the present invention.

[Explanation of symbols]

101 Electrostatic latent image carrier 102 Developed object 103 Pressure roll 104 Charging device 105 Exposure device 106 Developing device 107 Toner carrier 108 Toner 110 Heat generating roll 111 Tension roll 114 Recording support (recording paper) 116
Paper feed roll 117 Paper discharge roll 119 Optical static elimination lamp 120 Air layer

Claims (2)

[Claims] Claim 1: The electrostatic latent image carrier and the object to be developed are brought into partial contact, and a toner image is formed on the object to be developed, which is closely overlapped with the electrostatic latent image carrier on which the electrostatic latent image is formed. In an image forming apparatus that transfers the toner image by overlapping a developing object on which the toner image is formed and a recording support, (a) downstream of the developing process in the feeding direction of the developing object; and (b) the recording support contacts the development target upstream of the portion where the development target separates from the electrostatic latent image carrier, and (b) the contact point between the recording support and the development target; An image forming apparatus characterized in that a state of contact between the recording support and the object to be developed is maintained from the time to the transfer process. 2. The image forming apparatus according to claim 1, wherein in the transfer process, fixing is performed simultaneously with transfer by heating and pressure.