JP2624644B2 - Toner image recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus that forms a latent image electrostatically and then develops the latent image with toner particles.

[Background of the Invention]

As described in JP-A-59-2062, an apparatus for developing with a colored particle (toner particle) in order to form and visualize a charge latent image in electrostatic recording and electrophotographic recording is disclosed in JP-A-59-2062. After the image is transferred to the transfer member, the toner remaining on the recording member is generally removed by a cleaner to form a latent image. In this case, the apparatus is complicated, which has been a bottleneck in reducing the size and cost.

And as one means to solve this,
As described in Japanese Patent No. 4436, a proposal has been proposed in which a developing device is also used as a cleaner, but in this case, the operation is unstable and the reliability is lacking.

[Object of the invention]

An object of the present invention is to realize a small and simple recording apparatus.

[Summary of the Invention]

A feature of the present invention is a toner image recording apparatus that develops an electrostatic latent image formed on a photoconductor with a developing device with a toner and transfers the toner image formed on the photoconductor to a transfer body to obtain an image. The developing device has two rolls for conveying the powder developer and contacting the photoconductor, and after reversely developing and transferring the electrostatic latent image formed on the photoconductor, A part of the residual toner remains on the photoreceptor and forms the next electrostatic latent, and the downstream roll of the two rolls of the developing device is applied to the surface voltage of the photoreceptor. Applying a voltage of 4/5 to 2/3 to make the roll mainly perform a developing action, while applying a lower voltage to the upstream roll than to the downstream roll to perform a cleaning action and the downstream roll. Rolls that perform a weak developing action leave residual in the previous process Lying on the toner image recording apparatus characterized to remove the toner.

(Example of the invention)

The present invention can be applied to both electrostatic recording and electrophotographic recording, but for convenience of explanation, an electrophotographic apparatus using a magnetic brush reversal development method will be described.

The developer used is a two-component magnetic developer, a one-component magnetic toner, a one-component non-magnetic toner, or the like.

 FIG. 1 shows an embodiment of a recording apparatus to which the present invention is applied.

After the photoconductor 1 is uniformly charged by the charger 2 according to the rotation, the photoimage 3 is exposed to form a charge latent image.

At this time, charging and exposure are performed with a small amount of toner remaining on the photoreceptor in the previous image forming cycle.

Subsequently, the residual toner is removed and the reversal development of the latent image is performed by the developer in the developing device 5, and the removed toner is reused thereafter.

The developing device 5 is provided with a cleaning roll 13 on the upstream side when viewed from the rotation direction of the photoconductor 1, and a developing roll 7 on the downstream side.

The transport roll 12 is disposed below the cleaning roll 13 and the developing roll 7.

Both rolls carry the developer and rotate, but in particular, the cleaning roll 13 and the developing roll 7 slide on the drum surface.

In addition, a magnetic roll may be used for these rolls when the developer has magnetism.

With this configuration, the cleaning roll 13 not only provides a developing action, but also enhances the contact between the photoconductor 1 and the developer in order to easily remove the residual toner, and reduces the bias voltage applied to the cleaning roll 13 to the developing roll 7. Is set lower than the bias voltage so that the developing effect is reduced.

Then, the toner image developed on the photoreceptor 1 is transferred to a recording paper 8 as a transfer body by a transfer unit 9.
A small amount of untransferred toner remains. Here, the toner image transferred to the recording paper 8 is finally fixed by a fixing device (not shown).

Subsequently, the photoreceptor 1 is irradiated with light by an erasing lamp 10 to remove the charge remaining on the photoreceptor 1.

According to this recording method, since a cleaning mechanism for removing the residual toner can be provided in the developing device, the developing device and the cleaner can be integrated, the removed toner can be reused, and the toner scatters into the device. It is possible to realize a device having advantages such as the ability to suppress the occurrence of an error or the improvement of the maintainability by consolidating into one location.

Further, even when a conventional cleaner is provided after the transfer, the load can be reduced or simplified.

FIG. 2 illustrates a developing method suitable for the recording method of the present invention.

Next image forming cycle charging, cleaning after light image exposure,
This method of performing development has a good effect in the case of reversal development.

That is, in the case of the reversal development, the erasing of the residual charges by the erasing lamp 10 is a place where there is no residual toner, and can be completely erased.

Since the photosensitive member 1 is charged even when the toner is moved away by the charging, the toner is hardly affected by the charging, and the probability of exposing a portion where the residual toner is present in the next exposure is small. Can reduce the influence of the presence of

Further, the toner which is not charged in the charging step is also charged but has the same polarity as the original polarity of the toner, and tends to generate a repulsive force and has the same polarity even when collected in the developer, so that there is no problem.

Thus, the surface voltage V charged on the surface of the photoconductor 1
The uniformity of S is good, and the recording latent image can be reliably recorded.

The residual toner has good uniformity of the surface voltage VS of the photoreceptor 1, the charging polarity and the toner polarity are the same (that is, reversal development), the toner is easily removed, and when the developing method is the magnetic brush method, the conventional toner is used. The cleaner can be removed as easily as unnecessary.

Therefore, the cleaner is an auxiliary cleaner and can reduce the damage to the drum.

Further, by setting the bias voltage VB of the developing roller 7 lower than the surface voltage VS of the photoconductor 1, the influence of the residual charge pattern slightly generated by the residual toner can be completely removed.

The bias voltage VB of the developing roll 7 is preferably 4/5 to 2/3 of the surface voltage VS of the photoreceptor 1, and the bias voltage VC (not shown) of the cleaning roll 13 is set lower than this to facilitate the residual toner. Can be removed.

That is, the bias voltage VC of the cleaning roll 13
Is a bias voltage VB (4/5 to 2 of the surface voltage VB of the photosensitive member 1) applied to the developing roll 7 to have a cleaning action.
/ 3) lower.

This will be described in further detail. First, since the reversal development is performed, a toner having a charging characteristic of (+) is used, and the polarity of the bias voltage for development is also set to (+).

The remaining toner remaining on the photoreceptor 1 in the pre-imaging process includes those having a charge polarity of (+) and (-), but all are strongly charged to (+) by the charging of the charger 2. At this time, the surface of the photoconductor 1 is charged to the surface voltage VS.

Since the charging polarity of the toner in the developer is (+), the force for moving the toner to the recording latent image portion of the photoconductor 1 increases as the bias voltage for development increases. The amount of toner attached to the image portion increases, and the developing effect increases.

Accordingly, since the bias voltage VC of the cleaning roll 13 is lower than the bias voltage VB of the developing roll 7, the developing effect of the cleaning roll 13 is smaller than the developing effect of the developing roll 7.

If the bias voltage VB of the developing roller 7 is close to the surface voltage VS of the photosensitive member 1, fogging occurs. Therefore, the bias voltage VB of the developing roller 7 is adjusted so that the fogging is reduced and the developing effect can be increased. Surface voltage VS of body 1
Set to 4/5 to 3/5.

On the other hand, the cleaning effect depends on the electric force that attracts the toner remaining on the photoconductor 1 to the cleaning roll 13 and the developing roll 7.

For this reason, since the bias voltage VB of the developing roll 7 and the bias voltage VC of the cleaning roll 13 are set lower than the surface voltage VS of the photoconductor 1, the toner on the photoconductor 1 is developed from the surface of the photoconductor 1. A force is exerted to move to the roll 7 and the cleaning roll 13 side. However, as the bias voltage is lower, that is, the difference between the surface voltage VS of the photoreceptor 1 and the bias voltages VB and VC of the rolls 7 and 13 is larger, the cleaning effect is higher. Becomes larger.

Accordingly, since the bias voltage VC of the cleaning roll 13 is lower than the bias voltage VB of the developing roll 7, the cleaning effect of the cleaning roll 13 is less than that of the developing roll 7.
Cleaning effect.

Although the toner causing fog has a small charge amount, the residual toner is strongly charged by the charger 2 and therefore has a large charge amount, and has a large force to move from the photoconductor 1 to the cleaning roll 13 side. Easy to clean.

Therefore, by adopting the above-described relationship of the bias voltage for the developing roll 7 and the cleaning roll 13, it is possible to achieve both the developing effect and the cleaning effect of the residual toner.

As described above, according to the present invention, the cleaning voltage of the upstream cleaning roll 1 is set with respect to the bias voltage VB of the downstream developing roll 7.
3, the cleaning operation is performed by lowering the bias voltage VC, and the bias voltage VB of the developing roller 7 on the downstream side is applied by applying a voltage of 4/5 to 2/3 of the surface voltage VS of the photosensitive member 1 to fog. Is reduced and the developing action is enhanced.

According to this, the development efficiency is also improved, and an effect capable of coping with high-speed recording can be expected.

Incidentally, the photoreceptor of the present invention is not limited to a drum shape,
Needless to say, it can be replaced with a belt-shaped thing.

〔The invention's effect〕

According to the present invention, the residual toner removing device can be omitted or simplified, which is extremely effective in reducing the size and cost of the recording device.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a recording apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory view when reversal development is applied to the present invention. DESCRIPTION OF SYMBOLS 1 ... Photoreceptor, 2 ... Charger, 3 ... Optical image, 5 ... Developing device, 6 ... Developer, 7 ... Developing roll, 8 ... Recording paper,
10: Erase lamp, 13: Cleaning roll.

Continuation of the front page (56) References JP-A-53-105237 (JP, A) JP-A-57-38479 (JP, A) JP-A-59-133573 (JP, A)

Claims (1)

(57) [Claims] A toner image recording apparatus for developing an electrostatic latent image formed on a photoconductor with a developing device and transferring a toner image formed on the photoconductor to a transfer body to obtain an image; The developing device has two rolls for conveying the powder developer and contacting the photoreceptor, and reversely develops and transfers the electrostatic latent image formed on the photoreceptor, and then transfers the image. A part of the residual toner forms the next electrostatic latent image while remaining on the photoreceptor, and a downstream roll of the two rolls of the developing device is applied with respect to the surface voltage of the photoreceptor. Four/
A roll that mainly performs a developing action by applying a voltage of 5 to 2/3, and a cleaning action and a developing action that is weaker than the downstream roll by applying a lower voltage to the upstream roll than to the downstream roll. A toner image recording apparatus that removes residual toner in a previous process by using a roll that performs the following.