JPH0444064A - Image forming device - Google Patents

Abstract

PURPOSE:To easily vary image density by varying ultrasonic wave vibration corresponding to formed image density. CONSTITUTION:Toner passes through respective toner passing holes 31a with an electric field produced by a couple of electrodes 33 of a toner control means 30. The toner after passing through the toner passing holes 31a is conveyed to the side of a base electrode 60 with an electric field produced by an electrode impressed to the base electrode 60 and the toner-supply side electrode 3 of a toner control means 30. The toner control means 30 is vibrated by being given ultrasonic wave vibration from an ultrasonic wave vibration generating means 40 and the magnitude of the ultrasonic wave vibration by the ultrasonic wave vibration generating means 40 to vary the amount of toner passing through the toner passing holes 31a. Consequently, the density of a formed image is varied and the image density is easily adjusted.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an image forming apparatus using powder toner.

(Prior Art) Image forming methods using inkjet printers are known for word processors, facsimile machines, computers, and the like.

An inkjet printer is a typical so-called non-impact printer, which applies pressure to a predetermined liquid ink while applying ultrasonic vibrations using a piezoelectric element, etc.
A recorded image is formed on the recording paper by ejecting the liquid ink from an ink nozzle within a predetermined electric field, and controlling the ink particles by the electric field so that they adhere to the recording paper. Such an inkjet printer method has the advantage that it does not generate noise when forming an image and can form a clear image. On the other hand, in order to control the speed at which the ink soaks into the recording paper, it is necessary to use special paper with a surface treatment, etc. Also, since the ink is supplied from the nozzle, the nozzle absorbs the ink. There is a problem in that it is easily clogged by foreign objects.

In order to solve such problems with inkjet printers, an image forming apparatus using powder toner as an image recording medium is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-263962. This image forming apparatus uses powder toner particles to
A toner control means is provided in the pinhole-shaped toner passage hole to control the passage of the toner by an electrostatic attraction force generated in response to an image output signal, and the toner control means selects toner particles onto the recording paper. A predetermined recorded image is formed on the recording paper. In such devices, plain paper without surface treatment can be used as the recording paper, and furthermore, since fine powder toner is used, toner clogging in each toner passage hole is suppressed. .

A toner control means for controlling powder toner includes an insulating substrate provided with a large number of pinhole-shaped toner passage holes, and a toner control means provided between the insulating substrate so as to form an electric field in each toner passage hole. It has a pair of electrodes. Each pair of electrodes is provided with a pinhole-like through hole of the same size as each toner passage hole, and each through hole is provided on one side of each insulating substrate to correspond to each toner passage hole. Installed in a consistent manner.

Then, by applying a predetermined voltage between both electrodes to form an electric field in a predetermined direction within the toner passage hole, the toner particles are passed through the toner passage hole.

When toner particles are not allowed to pass through the toner passage hole, a predetermined voltage is applied between each electrode so that an electric field is formed in the toner passage hole in the opposite direction to that when the toner passes through the toner passage hole. Ru.

Further, a base electrode is disposed on the recording paper arrangement side, which is the toner passing direction side of the toner control means, and the recording paper is disposed on the base electrode.

A predetermined potential difference is provided between the base electrode and the toner supply side electrode of the toner control means, and an electric field is created so that the toner can reliably move toward the recording paper.

In such an image forming apparatus, dots are formed by toner passing through each toner passage hole, and an image such as a character is formed by a collection of the dots.

(Problem to be Solved by the Invention) However, in the above conventional example, since the voltage signal input to the electrode of the toner control means and the bias voltage applied to the base electrode are constant, the toner passes through each of the toner passage holes. Since the amount of toner is fixed, it is not easy to change the density of the formed image. Normally, in order to change the image density, digital processing such as a dither method is required, which complicates the configuration of the image forming apparatus. Therefore, even if the image density changes due to changes in the environment such as temperature and humidity, there is a problem in that it is not easy to adjust the image density.

The present invention is intended to solve the above-mentioned conventional problems, and an object of the present invention is to provide an image forming apparatus that can easily adjust image density.

(Means for Solving the Problems) The image forming apparatus of the present invention includes an insulating substrate provided with a toner passage hole, and a toner substrate with the insulating substrate sandwiched therebetween so as to form an electric field within the toner passage hole. a toner control means having a pair of electrodes provided with a through hole that communicates with the toner passage hole; and a toner control means that applies an electric field in at least a direction in which the toner passes through the toner passage hole according to image information. image information generating means for controlling the electric potential between the pair of electrodes of the toner control means; disposed on the toner passing direction side of the toner passage hole in the toner control means; a base electrode to which a voltage is applied so as to form an electric field in the toner passing direction together with an electrode on the side to which the toner is supplied; The above object is achieved by comprising an ultrasonic generating means whose vibration intensity is changed in accordance with the concentration.

(Function) In the image forming apparatus of the present invention, toner passes through each toner passage hole by an electric field formed by a pair of electrodes in the toner control means. The toner that has passed through the toner passage hole is transported toward the base electrode by an electric field formed by an electrode applied to the base electrode and an electrode on the toner supply side of the toner control means.

The toner control means is vibrated by applying ultrasonic vibrations by the ultrasonic vibration generating means, and by changing the intensity of the ultrasonic vibrations by the ultrasonic vibration generating means, the amount of toner passing through the toner passage hole is varied. do. As a result, the density of the formed image is changed.

(Example) The present invention will be described below with reference to Examples.

As shown in FIG. 1, the image forming apparatus of the present invention includes a toner container 10 containing powder toner. Above the toner storage container 10, there is a
The toner storage container 1 is connected to a toner storage section such as
Toner is sequentially replenished to 0. An opening 11 is provided at the bottom of the space in the toner storage container 10 in which the toner is stored.
An upper portion of a toner supply roller 20 serving as a toner supply means is fitted into the opening 11 . The toner contained in the toner container 10 is sequentially supplied downward by the rotation of the toner supply roller 20 .

Below the toner supply roller 20, a toner control means 30 is provided.
is provided in close proximity to the toner supply roller 20. The toner control means 30 includes an image information generation means 50.
The image signal is given by The image information generating means 50 is
It operates in response to signals from a device such as a word processor, facsimile, or computer, and generates electrical signals in accordance with image information.

According to this electric signal, the powder toner fed from the toner supply roller 20 is controlled by the toner control means 30, and a predetermined toner image is formed on the recording paper 70.

The toner control means 30 has a toner supply port=8- It may be pressed against -20.

The toner control means 30 is provided with an ultrasonic vibration generation means 40 that applies ultrasonic vibration, and a base electrode 60 is provided below the toner control means 30 so as to face the toner control means 30. ing.

A recording paper 70 on which a toner image is formed on the base electrode 60
is placed. The base electrode 60 may move in the direction of arrow A together with the recording paper placed thereon, or the base electrode 60 may be fixed and only the recording paper 70 may be moved by the recording paper transport means. good. When a predetermined toner image is formed on the recording paper 70 by the toner control means 30, the recording paper 70 is conveyed to a predetermined fixing device (not shown), and the toner image is transferred to the recording paper 70 by the fixing device. will be established.

The toner control means 30 has a horizontal insulating substrate 31, as shown in FIG. The insulating substrate 31 has a large number of pinhole-shaped toner passage holes 31 penetrating in the vertical direction.
a are arranged in a direction perpendicular to the plane of the paper. Further, an ultrasonic vibration generating means 40 is disposed on the insulating substrate 31, and the ultrasonic vibration generating means 40 applies ultrasonic vibration to the insulating substrate 31. The ultrasonic vibration generating means 40 is provided with a vibration intensity changing means 41 for changing the intensity of the generated ultrasonic vibration. The vibration intensity changing means 41 is adjusted when changing the image density to be formed, and for example, changes the voltage applied to the ultrasonic vibration generating means 40 to generate the ultrasonic vibrations generated by the ultrasonic vibration generating means 40. Change the amplitude of ultrasonic vibrations. Note that the vibration intensity changing means 41 may change the intensity of the generated ultrasonic vibrations by changing the frequency of the alternating current for driving the ultrasonic vibration generating means 40.

A common electrode 35 is provided on the upper surface of the insulating substrate 31, corresponding to each pinhole-shaped toner passage hole 31a. The common electrode 35 has a pinhole-shaped through hole 35a that penetrates in the vertical direction and has the same diameter as each toner passage hole 31a.
The common electrodes 35 are attached to the insulating substrate 31, with the through holes 35a aligned and communicating with the toner passage holes 31a of the insulating substrate 31. In addition, the insulating substrate 3
1, signal electrodes 33 are provided in correspondence with the respective toner passage holes 31a. Each signal electrode 33
Also, a through hole 33a having the same diameter as each through hole 31a of the insulating substrate 31 is provided so that each through hole 33a is aligned and communicated with each toner passage hole 31a of the insulating substrate 31. , each signal electrode 33 is connected to the insulating substrate 3
It is attached to 1.

The common substrate 35 on the insulating substrate 31 is grounded,
Further, an image information generating means 50 is connected to each signal electrode 33 provided on the insulating substrate 31, and an image signal (control signal) as a voltage signal is transmitted from the image information generating means 50 to each signal electrode 33. ) is entered. As a result, the voltage applied to each toner passage hole 3Ia can be adjusted. Each signal electrode 33 is given a predetermined positive potential and negative potential depending on the image information. For example, in the case of information for which an image should be formed, a voltage of +100V is applied, and for non-image information that does not need to be formed, a voltage of +100V is applied. In the case of image information,
It is controlled so that a voltage of -100V is applied.

The toner passing through the toner passage hole 31a in the toner control means 30 is formed by a common electrode 35 on the toner supply side of the toner control means 30 and a base electrode 60 provided on the toner passage side of the toner control means 3°. Due to the electric field generated, the recording paper 7 placed on the base electrode 60
0. A bias voltage set to a predetermined voltage by voltage changing means 61 is applied to the base electrode 60 .

An image forming process using an image forming apparatus having such a configuration will be described.

When the toner supply roller 20 rotates, the toner storage container 1
0 toner is supplied onto the common electrode 35 of the toner control means 30. The common electrode 35 is connected to the insulating substrate 3 by ultrasonic vibration generating means 40 provided on the insulating substrate 31.
Since ultrasonic vibration of constant amplitude is applied through 1,
The toner mass on the common electrode 35 is crushed as appropriate and falls from the through hole 35a of the common electrode 35 into the toner passage hole 3ia of the insulating substrate 31.

The toner particles that have fallen into the toner passage hole 31a of the insulating substrate 31 are controlled according to the image signal applied to the signal electrode 33, and fall onto the recording paper 70 or are returned onto the common electrode 35.

For example, when a positive voltage is applied to the signal electrode 33 by the image signal generating means 50, an electric field is generated in the toner passage hole 31a from the signal electrode 33 toward the common electrode 35. Due to this electric field, toner particles that are negatively charged in advance are
It is attracted to the signal electrode 33, passes through the signal electrode 33, and is supplied onto the recording paper 70 on the base electrode 60. Since a positive bias voltage is applied to the base electrode 60 with respect to the common electrode 35, the electric field formed by the base electrode 60 and the common electrode 35 causes the toner passage hole Ha to be
The supply of toner particles from the toner particles is facilitated. The toner that has passed through the toner passage hole 3La falls along the lines of electric force of the electric field.

The bias voltage applied to the base electrode 60 is sufficiently larger than the electric signal applied to the signal electrode 33, and is in the range of 300 to 1000 V in the case of negatively charged toner. If the bias voltage is less than 300V, the force with which the toner concentrates at the axial center position of the toner passage hole 31a becomes weak, and large dots are formed on the recording paper. As a result, the image formed on the recording paper 70 may be distorted. On the other hand, if the bias voltage is greater than 100 OV, there is a risk that discharge will occur.

A non-image signal is given by the image information generating means 50,
When a negative voltage is applied to the signal electrode 33, an electric field is formed in the toner passage hole 3La from the upper common electrode 35 toward the lower signal electrode 33, and the negatively charged toner is returned to the common electrode 35. It will be done.

When forming images in this way, for example, when correcting changes in image density due to changes in the environment such as ambient temperature and humidity, or when changing the density of an image to be formed, ultrasonic vibration Vibration intensity changing means 41 provided in generating means 40 is adjusted.

When increasing the density of an image, the vibration intensity changing means 41 increases the intensity of the ultrasonic vibrations generated by the ultrasonic vibration generating means 40. As a result, the toner control means 2
0 is vibrated with high intensity, and a large amount of toner passes through each toner passing hole 31a in which an electric field is formed in the direction in which the toner passes. As a result, the toner dots themselves that pass through each toner passing hole 31a and are formed on the recording paper 70 have a high density, and the diameter of the dots becomes thick (therefore, a high density image is formed on the recording paper 70). On the other hand, when lowering the density of the image, the vibration intensity changing means 41
The intensity of the ultrasonic vibrations generated by the ultrasonic vibration generating means 40 is weakened. As a result, the toner control means 20 is vibrated with a relatively low vibration intensity, and the amount of toner passing through each toner passage hole 31a in which an electric field is formed in the direction in which the toner passes is reduced. As a result, each toner passage hole 31a
The toner dots themselves that pass through and are formed on the recording paper 70 have a low density and a small diameter. Therefore, a low density image is formed on the recording paper 70.

In the image forming apparatus of the present invention, toner adheres to each pinhole-shaped toner passage hole 31a, and there is a risk that each toner passage hole 31a is clogged with toner. However, the vibration intensity is changed by the vibration intensity changing means 41. The inside of each toner passage hole 31a can be cleaned using the ultrasonic vibration generating means 40. When cleaning the inside of each toner passage hole 31a, when no image forming operation is performed on the recording paper 7o, the intensity of the ultrasonic vibration generated by the ultrasonic vibration generating means 40 is changed by the vibration intensity changing means 41. By adjusting the
The insulating substrate 31 provided with the toner passage holes 31a is vibrated with high intensity. As a result, the toner adhering to each toner passage hole 3ia is removed from the toner passage hole 3La, and the toner passage hole 31a is removed from the toner passage hole 3ia.
Fluidize and remove. As a result, each toner passage hole 3
The inside of 1a is assumed to be free of toner.

(Effects of the Invention) As described above, the image forming apparatus of the present invention changes the ultrasonic vibrations generated from the ultrasonic vibration generating means in accordance with the density of the image to be formed. Concentrations can be changed very easily.

Figure 2 is a configuration diagram of the main parts.

DESCRIPTION OF SYMBOLS 10... Toner storage container, 20... Toner supply roller, 30... Toner control means, 31... Insulating substrate, 31a... Toner passage hole, 33... Signal electrode, 3
5... Common electrode, 40... Ultrasonic signal generating means, 4
1... Signal strength changing means, 50... Image information generating means.

that's all

Claims (1)

[Claims] 1. An insulating substrate provided with a toner passage hole, and a through hole communicating with the toner passage hole sandwiching the insulating substrate so as to form an electric field within the toner passage hole. a toner control means having a pair of electrodes provided in a formed state; and a toner control means configured to form an electric field in at least a direction in which the toner passes in the toner passage hole according to image information. an image information generating means for controlling the potential between a pair of electrodes; and an electrode disposed on the toner passing direction side of the toner passage hole in the toner control means, and an electrode on the side of the toner control means to which the toner is supplied. and a base electrode to which a voltage is applied to form an electric field in the toner passing direction, and the toner control means are provided to apply vibration, and the vibration intensity is changed in accordance with the density of the image to be formed. An image forming apparatus comprising: an ultrasonic generating means for generating an ultrasonic wave;