JPH0434566A - Recorder - Google Patents

Abstract

PURPOSE:To obtain a device which is easily miniaturized, whose cost is easily reduced and which is economical and high in safety by using an electrostatic charge means also as a residual toner image uniformizing means. CONSTITUTION:An electrical conductive brush roller 21 is obtained by plating an electrical conductive fiber 22 whose volume resistance value is 10<2> - 10<10>OMEGA.cm on the outside circumference thereof and an AC or DC voltage is impressed on a roller base 23. Then, when an electrostatic latent image holding body 1 is uniformly electrostatically charged to negative, the negative voltage or the AC voltage which is biased to the negative is impressed on the brush roller 21. In such a case, it is good that the rotating direction of the roller 21 is set to any rotating direction of the holding body 1. However, it is desirable that the circumferential speed thereof is set to be higher than the holding body 1 or little slower than it. Thus, the electrostatic charge of the electrostatic latent image holding body and the uniformizing of the residual toner of transfer can be simultaneously and surely executed. Besides, the device is easily miniaturized, the cost thereof is easily reduced and contamination by the product of discharging is eliminated.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to a recording device based on an electrophotographic method, and more specifically, to a recording device that is capable of recording an image without using a cleaning device for cleaning residual toner after transfer. The present invention relates to a cleanerless recording device that performs.

(Prior Art) In a recording apparatus based on an electrophotographic method, a recording apparatus (hereinafter referred to as a recording apparatus) that collects residual transfer toner into a developing device at the same time as development is performed by a developing device (means) without using a cleaning device for cleaning residual toner. (referred to as a cleanerless recording device) is disclosed in, for example, Japanese Patent Application Laid-open No. 59-133573.
This method is known from Japanese Patent Application Laid-Open No. 157661/1983. These publications disclose the basic idea of the cleanerless recording device, and the gist thereof can be summarized as follows.

In other words, as shown in FIG. 5, which shows a cross-sectional view of the main structure, in electrophotographic printers such as laser printers,
The well-known reversal development method is often used. In the reversal development method, toner particles 2 charged with the same polarity as the electrostatic latent image carrier (photoreceptor) 1 are used to remove charge-free areas (or the amount of charge) on the surface of the electrostatic latent image carrier 1. The toner particles 2 are attached to the areas (areas where there is little electric charge), and the toner particles 2 are not attached to the areas where electric charges are present. In order to realize such selective toner adhesion, the toner carrier 4 in the developing device (developing means) 3 has a potential VO of the charged portion of the surface of the electrostatic latent image holding member 1 and a potential Vt0 of the uncharged portion. The voltage between V (l V t l < l Vb l < l V
o l') is applied, the toner adhesion to the electrostatic latent image carrier 1 is suppressed by the electric field between the charged part, and the toner 2 is applied to the electrostatic latent image carrier 1 by the electric field between the charged part and the uncharged part. Attach. The toner 2 adhering to the electrostatic latent image holder 1 is transferred to an image support 6 by a well-known transfer device 5. In this transfer step, generally not all toner is transferred, and residual toner 2' is distributed in the form of an image on the surface of the electrostatic latent image holding member 1 after transfer.

In a normal electrophotographic device, a cleaner 7 shown by a broken line is used.
After collecting the transferred residual toner 2', the charge on the surface of the electrostatic latent image holding member 1 is removed by the static eliminating lamp 8, and the electrostatic latent image forming process (uniform charging process by the charger 9 and light beam unit O) is performed again. (exposure process). On the other hand, in a cleanerless recording apparatus, the residual toner 2' is subjected to a developing process without using the cleaner 7, and the residual toner 2' is collected into the developing device 3 at the same time as the development.

Strictly speaking, of the latent image formed by exposure with the light beam 10, the residual toner 2' present in the charged portion (that is, the unexposed portion or the non-image portion) is charged by the charger 9 to be the same as the latent image. It is definitely charged with polarity. Therefore, one particle of toner 2 is transferred from the toner carrier 4 to the electrostatic latent image carrier 1.
is transferred to the toner carrier 4 side by an electric field that suppresses the transfer (that is, an electric field due to the potential difference between Vo and vb).

At the same time, the untransferred toner 2' existing in the uncharged area (that is, the exposed area or the image area) receives a force from the toner carrier 4 toward the electrostatic latent image holder 1 and is transferred onto the surface of the electrostatic latent image holder 1. remain in the New toner particles 2 are transferred from the toner carrier 4 to this uncharged portion, and development and cleaning are performed simultaneously.

In this way, in the cleanerless recording device, the cleaner 7 and cleaned toner (that is, waste toner)
Since there is no need for a waste toner box to store the waste toner, the device can be easily downsized and simplified.

Further, since the residual toner 2' after transfer is collected by the developing device 3 and reused, it is economical because no waste toner is generated, and the electrostatic latent image holding member 1 is not rubbed by the cleaning blade. Therefore, many advantages can be obtained, such as making it possible to extend the life of the electrostatic latent image holder 1.

However, in this cleanerless recording device,
Ghost images may appear due to the following reasons.

First, in a high humidity environment, the paper used as the image support 6 absorbs moisture and lowers its resistance, which generally reduces transfer efficiency and leaves a large amount of toner remaining on one surface of the electrostatic latent image carrier. Tend. If the amount of transferred residual toner 2' becomes too large, the developing device (developing means) 3 will not be able to completely clean the transferred residual toner 2', and the untransferred toner 2' will remain in the non-image areas. A positive ghost appears (hereinafter referred to as a positive ghost or positive memory).

Second, if the amount of transferred residual toner 2' becomes too large, the transferred residual toner 2' blocks the light beam 10 during the exposure process with the light beam 10, so that the surface potential of the electrostatic latent image holder 1 is insufficiently attenuated. , a potential state intermediate between VO and Vi (V
L'). In such a region, the developing voltage is v, -vt', which is a smaller value than the developing voltage vb-vL of the surrounding exposed area, so that the toner is transferred from the toner carrier 4 to the electrostatic latent image carrier 1. The amount of transferred toner is small compared to the surrounding area, and therefore, a residual toner image appears as a whiteout image (hereinafter referred to as a negative ghost or negative memory) in the image area of the transferred image. This phenomenon is particularly noticeable in halftone images consisting of a set of halftone dot images or line images.

On the other hand, in Japanese Patent Application Laid-Open No. 12-203183,
It is disclosed that ghosts can be removed by applying a voltage to a conductive brush 12 having a cross-sectional shape shown in FIG. 6 and bringing it into light contact with the surface of an electrostatic latent image holder. That is, a voltage having a polarity opposite to the charged polarity of the toner is applied to the conductive brush 12 by the DC power supply 13, and the untransferred toner 2' is once attracted to the brush 12 by Coulomb force. As a result, the amount of untransferred toner 2' on the surface of the electrostatic latent image holding member 1 is significantly reduced, and the occurrence of the ghost is prevented.

(Invention or problem to be solved) However, the following two problems arise in the above method.

(2) Instead of removing the cleaner, it is necessary to separately install the equalizing means 12 such as the brush described above, so that a great effect cannot necessarily be obtained in terms of miniaturization and cost reduction of the apparatus. In particular, the electrical resistance of the conductive brush 12 cannot be easily adjusted during manufacturing, and the fibers are easily broken, resulting in poor yield, high price, and crystallization. There is a problem in that a new power source must be prepared for this purpose.

(2) When a corona charger as shown in FIG. 5 is used as the charging means 9 for uniformly charging the electrostatic latent image holder 1, a large amount of ozone is generated as a corona discharge product. This large amount of ozone is not only harmful to the human body, but also
This causes deterioration of components such as the electrostatic latent image holder 1.

As described above, the conventional cleanerless recording apparatus has problems such as miniaturization and low cost of the apparatus and generation of harmful discharge products, and cannot be said to be fully satisfactory in practical terms.

The present invention was made in response to the above-mentioned circumstances, and aims to provide an economical and highly safe recording device that can be easily made smaller and lower in price, does not generate harmful discharge products, and is therefore economical and highly safe. shall be.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a cleanerless recording apparatus having the above configuration and functions, in which the charging means also serves as a residual toner image uniforming means. Make it the gist.

(Function) In the cleaner-less recording apparatus according to the present invention, since the charging means also serves as a residual toner image uniforming means, it is not necessary to install a cleaner or separately installing a residual toner image uniforming means, making it possible to realize a true cleaner-less recording apparatus. can be realized. In other words,
By configuring the charging means with a contactor to which a voltage is applied, when the electrostatic latent image carrier is uniformly charged by the charging means, transfer residue remaining on the electrostatic latent image carrier after transfer is removed. While the toner is being slid, the required voltage is applied. By applying this voltage, the distribution of residual toner after transfer is disturbed, and the distribution of residual toner after transfer is made uniform as a whole. Therefore, residual toner after transfer will not cause ghosts in the next image. Furthermore, charging of the electrostatic latent image holder is not performed by so-called corona discharge, but by well-known electric field radiation (Field Emjs).
Since the process is carried out using a mechanism such as ston) or ion conduction, there are almost no discharge products and there is no adverse effect on the human body or the electrostatic latent image holder.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a cross-sectional view of the main parts of an example of a recording device according to the present invention. Components common to FIGS. 5 and 6 already described are designated by the same numbers. Attached,
Explanation will be omitted.

The characteristic points of this embodiment are that the residual toner image leveling means 12 is not provided in the recording apparatus having the configuration shown in FIG. 2. Using the brush roller 21
It is a point. The conductive brush roller 21 has a volume resistance value of 1
The roller base 23 on which the brushes 22 are installed is made of a material such as metal. A rigid conductor or an elastic conductor such as conductive rubber or conductive foam can be used. The thickness of the fibers forming the brush 22 is preferably in the range of 0.5 denier to 10 denier, and the flocking density is 500 denier.
A range of 0 fibers/cd to 10,000 fibers/c- is good, and a preferable fiber length is a range of 0.5 to 5.0 fins. These values are mainly based on requirements from the charging function, which will be described later.

The conductive base 23 of the brush roller 21 is connected to an AC power source 2.
4 or a DC power supply 25, or a power supply connected to these, AC or DC voltage is applied.

In order to uniformly negatively charge the electrostatic latent image holder, a negative voltage or a negatively biased alternating current voltage is applied to the brush roller 2. In this case, the direction of rotation of the brush roller 21 is the same as the rotation direction of the electrostatic latent image holder 1.
Although it may be in either the opposite direction, it is preferable that the peripheral speed is different from the surface speed of the electrostatic latent image carrier 1. That is,
It is desirable that the circumferential speed of the brush roller 21 be faster than or slightly slower than the circumferential speed of the electrostatic latent image holder 1.

In particular, a speed of 1.2 to 5.0 times that of the electrostatic latent image holder 1 is more preferable. It is desirable that the contact width between the brush roller 21 and the electrostatic latent image holder 1 be 0.5 m+s or more.

For example, the peripheral speed of the electrostatic latent image holding body 1 is set to 40+u+/se.
e, outer diameter of the brush roller 21 25 m + is resistance value of the fibers forming the brush 22] 05Ω・(2), length of the fibers 2.
5mm, fiber thickness 3 denier, flocking density 40,000/C
- The circumferential speed of the brush roller 21 configured under the conditions of 60+m
/sec.

The applied voltage is -50 to an AC voltage with a peak value difference of 800
The results obtained when a DC voltage of 0 V was superimposed and the contact width between the brush roller 21 and the electrostatic latent image holder 1 were set to 3 1 are shown below.

First, under the above conditions, the organic photoreceptor (electrostatic latent image carrier) 1
The surface of the was uniformly charged to -450V to -500V. This charged surface is exposed to laser light and developed by a well-known two-component development method or a one-component non-magnetic development method described in Japanese Patent Application No. 1-81921, and then a toner image is placed on a transfer paper 6 using a well-known transfer charger 5. transcribed.

After the transfer, untransferred toner 2' remained on the organic photoreceptor (electrostatic latent image holder) 1 in the form of an image. residual toner 2'
After the surface of the organic photoreceptor 1 to which the organic photoreceptor 1 has been charged is neutralized by the static eliminating lamp 8, it reaches the bottom of the charging brush roller 21 again.

The residual toner 2' after transfer is made uniform by the sliding force of the brush roller 21, and at the same time is vibrated by the alternating current electric field, so that it is further made uniform. at the same time,
A negative charge is applied to the surface of the organic photoreceptor 1 by the conductive fibers 22 of the plan roller 21 in contact with the surface of the organic photoreceptor 1, so that the organic photoreceptor 1 is uniformly charged.

Of course, 1500v to 1800v is applied to the plan roller 21.
Although similar uniformity and charging effects can be obtained when only a DC voltage of about 100% is applied, even more significant effects can be obtained by superimposing alternating current.

It is preferable that the AC voltage has a peak value difference of 300 to 1200 V and a frequency of 200) to 5 KHz.

Further, the absolute value of the superimposed DC voltage is set to the desired potential of the electrostatic latent image carrier 1 or a value larger than this (in particular, 200 to 200
A value as large as 50CIV) is desirable. The fibers 22 for the brush roller 21 are made of rayon, polyamide, acrylic, tetrafluoropolyethylene, etc., which are subjected to conductive treatment.

In this way, the brush roller 21 can uniformize the residual toner and charge the photoreceptor at the same time.

Example 2 In the case of Example 1, instead of the brush roller 21,
A fixed type blank 31 shown in FIG. 2 may also be used. In this case as well, electrically, the same operation and effect was obtained under substantially the same conditions as in Example 1. In this embodiment, it is desirable that the contact width between the brush 31, that is, a mechanism that also serves as a charging and residual toner image uniforming means, and the electrostatic latent image holder 1 is three or more angles.

Example 3 In the case of Example 1, instead of the blank roller 21,
A conductive roller 41 configured as shown in FIG. 3 in cross section may also be used. In this embodiment, when the electrostatic latent image holder 1 is made of a rigid body, it is desirable that the conductive roller 41 be made of an elastic body. FIG. 3 shows an example in which a conductive rubber layer 43 is provided around the outer periphery of a metal shaft 42, and a surface layer 44 made of conductive resin or elastomer is provided on the surface thereof. Of course, a single layer type without the surface layer 44 may be used.

In the configuration of the recording apparatus, the conductive roller 41 has a surface roughness of 0.3 μmRz% 1.2 μmRz or 1
When experiments were conducted using a conductive roller 41 of 5 μmRz, good charging and uniformity functions were observed in all cases. It should be noted that the conductive roller 41 is suitably made of materials of 103 to 1010 Ω for the conductive rubber layer 43 and the surface layer 44, excluding the conductive shaft 42, and the electrical and mechanical conditions are the same as in the embodiment. It may be almost the same as case 1.

Example 4 In the case of Example 1, instead of the brush roller 21,
A well-known magnetic brush 51 having a main part shown in cross section in FIG. 4 may be used. The second magnetic brush 51 has a structure in which a fixed or rotating sleeve 53 made of a non-magnetic material is surrounded by a fixed or rotating magnet roller 54, and well-known magnetic particles are attached around the sleeve 53. It is. As magnetic particles, the volume resistance is 102~
1o10Ω・■, average particle size is 10μml to 200μ
Iron powder, ferrite, etc. are used. In this case as well, the electrical conditions were substantially the same as in Example 1, and similar effects and effects were obtained. Other electrical and mechanical conditions may be substantially the same as in the first embodiment.

[Effects of the Invention] As described above, according to the recording apparatus of the present invention, the charging and residual toner image uniformizing means simultaneously and reliably charges the electrostatic latent image holder and uniformizes the residual toner after transfer. Can be executed. Furthermore, it is possible to obtain a cleanerless recording apparatus that can easily be made smaller and lower in price, is free from contamination by discharge products, and can always output good images without ghosts.

[Brief explanation of the drawing]

FIGS. 1 to 4 are cross-sectional views showing an example of the configuration of a main part of a recording apparatus according to the present invention, and FIGS. 5 and 6 are cross-sectional views showing a configuration of main parts of a conventional recording apparatus. 1...Latent image holder (photoreceptor) 2...Toner 3...Developing device 5...Transfer device 9... ...Charger 21...Brush roller 41...Elastic conductive roller 51...Magnetic brush roller love 31 Fig. 2 Fig. 3 Fig. 5 Fig. 4 Figure 6

Claims (3)

[Claims] (1) An electrostatic latent image carrier, a charging means for uniformly charging the surface of the electrostatic latent image carrier, and a charging means for attenuating a portion of the surface charge of the electrostatic latent image carrier charged by the charging means. means for forming an electrostatic latent image; a developing means for forming a toner image by attaching toner to the electrostatic latent image; a transfer means for transferring the formed toner image onto an image support; a residual toner image uniforming means that later disturbs the residual toner image that remains on the electrostatic latent image bearing surface and makes the distribution of toner uniform; A recording apparatus that develops an electrostatic latent image, wherein the charging means also serves as a residual toner image uniformization means. (2) The recording apparatus according to claim 1, wherein the charging/residual toner image uniformizing means comprises a conductive contact to which a voltage is applied. (3) The recording device according to claim 2, wherein the voltage applied to the conductive contact is a voltage obtained by applying a DC voltage to an AC voltage.