JPH043184A - Optical printer - Google Patents

Abstract

PURPOSE:To prevent the wasteful consumption of a toner and the splashing of the toner by applying the electric field of the direction opposite from the electric field at the time of a recording operation to electrooptical materials for optical modulation in order to recover the electrooptical materials from photofatigue. CONSTITUTION:This printer is equipped with a photofatigue compensating means which applies the electric field to produce the quantity of transmitted light without annihilating the charge of a photosensitive body 5 in excess of a developing level in the direction reverse from the direction at the time of the recording operation to the plural electrooptical materials at every ending of the recording operation for the prescribed period by a recording control means. The electric field E2 of the direction opposite from the direction of the electric field E1 impressed in the recording period T1 is applied to an optical shutter head 10 during a non-recording period T2, by which the internal polarization generated by the electric field E1 in one direction applied during the recording period T1, i.e. the photofatigue is eliminated. The electrooptical materials constituting the optical modulating part are recovered from the photofatigue in this way without generating the waste of the toner or splashing of the toner in the device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses electro-optic materials such as PLZT for optical modulation, and applies driving voltages corresponding to recorded information to a plurality of electro-optic materials. The present invention relates to an optical printer that changes the amount of light transmitted through a light modulation section including an electro-optic material, and then performs recording using an electrophotographic process using the transmitted optical signal.

[Conventional technology]

In this type of optical printer, the plurality of electro-optic materials are always irradiated with light from a light source, and by applying a driving voltage to the electro-optic materials at the required locations, light modulation at that location is performed. The recording light passes through the recording light.
During long-term use, internal polarization of the electro-optic material due to repeated application of driving voltage for recording while being irradiated with light, that is, optical fatigue, occurs, resulting in drive that maximizes transmittance. It was found that the voltage, the so-called half-wave voltage, is variable.

Therefore, in order to prevent the change in the half-wave voltage by eliminating the internal polarization described above and recovering optical fatigue, the applicant first proposed a method to prevent changes in the half-wave voltage during the non-recording period when recording is not performed. We have proposed an electro-optical material in which an optical fatigue recovery voltage is applied that generates an electric field in the opposite direction to the electric field generated by the drive voltage applied during the recording period (for example, in Japanese Patent Application No. 1-170965). (see issue).

[Problem to be solved by the invention]

By the way, in an optical printer that performs recording using an electrophotographic process, an optical signal is irradiated onto a photoconductor to form a static latent image, and then toner is attached to the electrostatic latent image and the developed toner image is printed on recording paper. Recording is performed by transferring and fixing the image onto the image forming apparatus, and it can be roughly divided into two types depending on the type of development described above. One is called the positive-positive method, in which the charge on the photoconductor that is irradiated with light disappears, and during the development process, toner adheres to the remaining charge areas other than the areas where the charge disappeared.The other is the negative-positive method. Similarly, the charge on the portion of the photoreceptor that is irradiated with light disappears, and in the developing process, toner adheres to the portion where the charge disappears.

The aforementioned optical printer of the prior application is configured to apply a voltage for recovering from optical fatigue to each electro-optic material during the non-recording period, but the application of the voltage for recovering from optical fatigue also causes optical modulation at that location. The recording light will pass through the recording light.

Therefore, when the configuration of the earlier application described above is applied to an optical printer using the electrophotographic process that performs the negative-positive method development described above, the photofatigue recovery voltage is applied during the non-recording period when no recording is performed. Therefore, although this does not seriously impede recording, the part of the photoreceptor that is irradiated with the recording light that has passed through the light modulation section is affected by the application of the photofatigue recovery voltage.
A large amount of toner will adhere during the developing process.

The toner in this area is not involved in recording and is scraped off with a cleaner without being transferred to the recording paper, resulting in wasted toner consumption and furthermore, wasteful toner adhesion. Repeated scraping may cause the toner to scatter, which may easily cause stains inside the optical printer or stains on the recording.

In view of the above circumstances, an object of the present invention is to reduce optical fatigue of the electro-optic material constituting the light modulating section without wasting toner or scattering the toner inside the device in a negative-positive developing process. The object of the present invention is to provide an optical printer that can recover.

Means for Solving Problem C] The characteristic configuration of the optical printer according to the present invention is that a light modulating section in which a plurality of electro-optical materials are arranged in a row is provided between a charged photoreceptor and a light source, and a recording control means for applying a drive voltage for light modulation according to recording information to each of the electro-optical materials, and a developing means for attaching toner to a portion of the photoreceptor where charge disappears due to light irradiation; Each time a recording operation for a predetermined period of time is completed by the recording control means, an amount of light transmitted through the plurality of electro-optical materials is transmitted in a direction opposite to that during the recording operation and does not exceed the development level and eliminate the charge on the photoreceptor. and optical fatigue compensation means for providing an electric field.

[For production]

According to the optical printer of the present invention, the optical fatigue compensation means applies an electric field in the direction opposite to that during recording operation to the plurality of electro-optic materials, so that the electric field in one direction is applied to the plurality of electro-optic materials during the recording operation. Even if internal polarization occurs due to repeated application, it can be eliminated, and the electric field in the opposite direction is such that the amount of transmitted light is such that it does not eliminate the charge on the photoreceptor beyond the development level. Therefore, by performing the above-described optical fatigue recovery operation, it is possible to prevent toner from adhering to the area of the photoreceptor that is irradiated with the light that has passed through the light modulation section.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing a schematic configuration of an optical printer to which the present invention is applied.

The optical shank head (10) made of an electro-optic material has a polarizer (
P) and an analyzer (8) with their polarizations perpendicular to each other. The light from the lamp (1) is
) is condensed by a reflecting mirror (2) provided behind the mirror (2), and is incident on a light source (10) via a polarizer (P). The Mitsuya Notahe 7 (10) selectively changes the polarization angle of the incident light in accordance with image information indicating the image to be recorded, and controls the light that passes through the analyzer (8). . The light that has passed through the analyzer (8) is guided by the focusing rod lens array (3) to the surface of the photoreceptor (5), which is charged with the charger (4), and is then deposited on the surface of the photoreceptor (5). Forms an electrostatic latent image. This electrostatic latent image formation is performed by character writing of the optical shank head (10), and is formed as a negative latent image. The formed negative latent image is reversely developed by a developing device (6).

Below, the process from latent image formation to development is shown in Figures 2 (a) to (
This will be explained using the potential model diagram of c).

The photoreceptor (5) rotating in the direction indicated by the arrow in FIG. As mentioned above, light is irradiated on the black area of the image based on the image information, and the charge in that area disappears, resulting in a potential of C+νr (see Figure 2).
+1)). The sleeve (6a) of the developing device (6) is
A predetermined bias voltage (+vb) is applied to the photoreceptor (5).
is applied, and the positively charged toner present in the developing device (6) has a potential C+ν of the portion of the photoreceptor (5) where the charge has disappeared due to this bias voltage [+νb] and light irradiation.
r] and is selectively adsorbed depending on the relationship with the potential (+Vr
) are developed (see FIG. 2(c)).

In this way, predetermined image information is developed. Thereafter, in FIG. 1, the formed toner image is transferred onto recording paper by a transfer device (7). The residual toner remaining on the surface of the photoconductor (5) after the transfer operation is collected by the cleaner (8), and the charge remaining on the surface of the photoconductor (5) is removed.
It is erased by the static eliminator (9).

In this embodiment, PLZT is used as the electro-optic material constituting the nozzle (10) to the optical shutter. Third
As shown in the figure, this light beam is 7 F' (10
) includes a plurality of shutter elements (11) arranged in an array.

Each shank element (11) is divided by grooves formed in the PLZTi body, and is sandwiched between electrodes (12) and (13) 5 formed on the walls of these grooves. The electrode (12) is connected to each shutter element (11).
The electrodes (1
3) is provided in common to all shank elements (11).

FIG. 4 is a diagram showing a drive circuit for the optical shank head in this embodiment. In this figure, each shank element (11) of the optical shutter node (10) is shown as a capacitor.

In order to drive 7F' (10) to the optical shank, a first drive circuit (20) is connected to an individual electrode (12) for each shutter element (11), and a second drive circuit (
30) is connected to the common electrode (13).

The first drive circuit (20) includes a soft register (21) into which image data, which is image information indicating an image to be recorded, is input serially one line at a time, and a shift register (21).
In order to collectively latch the image data input to the sub-circuit (22) and the launch circuit (22), a DC drive voltage ( The driver (23) is provided with a driver (23) that selectively applies Vl (>O)].
A clock signal (CK) is used to specify the timing of applying the driving voltage [ν1] to the individual electrode (12).
is man-powered.

The second drive circuit (30) includes a first transistor (31) that grounds the common electrode (13) in its on state;
When this first transistor (31) is in an off state, it is turned on and a DC voltage (V2 (>0
): a second transistor (32) that applies l. A control signal (Sl) that becomes high level and turns on the first transistor (31) only during execution of a recording operation is input to the base of the first transistor (31).

Next, the operation of this optical printer will be explained with reference to the time chart shown in FIG.

When a print command is input to record an image, the lamp (1) is turned on, and image data is input line by line to the first drive circuit (20) and launched. In response to the clock signal (CK), the driver (23) selectively applies a driving voltage (v1) to each individual electrode (12) according to the latched image data.At this time, Since the control signal (Sl) input to the second drive circuit (30) is high-level, the common electrode (
13) is grounded. Therefore, the positive drive voltage [
v1] applied to the individual electrode (12) and the common electrode (13
), an electric field [E1] in a predetermined direction is formed between the shutter elements (11
) is turned on and light is transmitted. Moreover, the driving voltage [ν1
] was not applied to the individual electrode (12) and the common electrode (1
Since no electric field is formed between these individual electrodes (
The shutter element (11) corresponding to 12) remains off and light is blocked. This on/off control of the shutter element (11) is performed for each line of image data in synchronization with the rotation of the photoreceptor (5).
It is executed repeatedly until the image of the page is recorded.

When the recording for one page is completed, the second drive circuit (3
The control signal (Sl) manually input to the terminal 0) is set to low level, and the clock signal (CK) is set to low level. Therefore, the second transistor (32) is turned on and a positive voltage [v2] is applied to the common electrode (13), while the now individual T4 pole (12) is kept at ground level (zero level). This allows individual electrodes (1
2) and the common electrode (13), there is a recording period (
An electric field [E2] in the opposite direction to the electric field [E1] in T, ) is formed, and all the shank elements (11) are turned on by the action of this electric field [E2]. This non-recording period (
During T2), the light passes through all the shank elements (11) of the optical shack head (10) and is guided to the surface of the photoreceptor (5), so that the charge on the surface of the photoreceptor (5) disappears. .

In this embodiment, as mentioned above, the non-recording period (
T2), the electric field [E1] applied during the recording period (T,)
The electric field [E2] in the opposite direction to the optical shutter is
0), internal polarization caused by the unidirectional electric field [E1] applied during the recording period (T1), that is, optical fatigue, is eliminated. Therefore, the optical shank head (10
) has not substantially changed from the initial characteristic shown by the solid line.

The dashed line in Figure 6 shows the optical shank head after long-term use (4 hours of continuous use) when no electric field was applied to the optical shaft head (10) during the non-recording period (T2). It is a characteristic of

The data shown in FIG. 6 was obtained under the following conditions.

- Peripheral speed of photoreceptor (5): 18 cm/sec.

・Duty ratio (d) of clock signal (CK) during recording period (T1) (=tl/12): 50%・
1 page recording period T: 1.1 sec, (A4 landscape)
- Non-recording period T2: 0.8 sec.

・Electric field (E2): 28V In addition, during the non-recording period (T2), the optical shutter head (10
) is the optimum strength desired for the electric field applied during the recording period (
T, ) depends on the time when the electric field is applied to the optical shank at 7F (10), and specifically, the duty ratio (d) of the clock signal (CK) during the recording period and the recording period (T1
) and the non-recording period (T2) (=T, /T2). For example, T+ = 1.1se (.

In the case of Tz = 0.8 sec, the voltage [E2] to make the electric field applied during the non-recording period (T2) the optimum strength is a value proportional to the duty ratio (d) as shown in Fig. 7. become.

In the embodiment described above, a positive drive voltage 1:Vl) is applied to the individual electrodes (12) during the recording period (r,), while a positive drive voltage 1:Vl) is applied to the common electrode (13) during the non-recording period (T2). However, the recording period (T1
) and during the non-recording period (T2).
In order to change the direction of the electric field applied to 0), the common electrode (13) is always grounded, while the individual electrodes (12) are connected during the recording period (T, ) and during the non-recording period (T2). Voltages of different polarities may be applied.

By the method of driving the optical shank head (8) as described above, a stable exposure operation is always achieved without fluctuation in the amount of transmitted light of the optical shutter head (10).
During the non-recording period (T2) with respect to the page recording period (T1), light passes through all the shutter elements (11) of the optical shutter head (10) and is guided to the surface of the photoreceptor (5). annihilate most of the charge on the surface of Therefore, if all operations are the same as during normal image formation, the area where the charge has disappeared during the non-recording period (T2) will be developed by the developing device (6) and a large amount of toner will be consumed. This may cause contamination within the device due to toner scattering, which may place a large load on the cleaner (8) and cause problems such as poor cleaning.

Therefore, during the non-recording period (T2), the optical shutter is
As an electric field applied to the photoreceptor (5 volts), the developing bias potential (+v
(corresponding to b)), the amount of transmitted light shall not be eliminated.

To explain more specifically, in the relationship between the driving voltage and the amount of transmitted light shown in FIG. 6, in the region of [νR] of the rotation, each of the cylinders (11) is substantially maintained in a closed state. On the other hand, as shown in Figure 7, the non-recording period (T2)
Voltage to make the electric field applied to the optimum strength [v2]
is proportional to the duty ratio (d) of the clock signal (CK) during the recording period (T1), and has a relationship that if the duty ratio (c) is small, the above voltage [ν2] can also be small. From this, the duty ratio (d) is set so that the voltage [ν2] is in the region [vR] that maintains each shutter element (11) in the closed state, and the voltage that has the relationship shown in Fig. 7 is set. [V2] is the non-recording period (T2
) is applied to the optical shutter head (10).

Note that the above-mentioned optimal voltage (ν2) for recovery from optical fatigue.

is V2ccv, H(t, + r,) / (t 2
・Tz) Therefore, the duty ratio b+/
lz) as described above, the non-recording period (T2) may be made longer than the recording period (T1).

〔Effect of the invention〕

As described above, in the optical printer according to the present invention, an electric field is applied in the opposite direction to that during recording operation in order to recover the optical fatigue of the electro-optic material for light modulation, and the photosensitive material is Since it applies an electric field to the amount of transmitted light that does not cause the body's charge to disappear, the above-mentioned optical fatigue recovery operation is performed after the end of the recording operation for a predetermined period, so that toner is wasted even though it is not involved in recording at all. Although it is a negative/positive optical printer that records by attaching toner to the area where the electric charge has disappeared by irradiation with recording light, it is possible to avoid wasteful consumption of toner and the associated internal problems. It is now possible to prevent toner from scattering. Therefore, as a whole, it has become possible to provide an optical printer that can recover from optical fatigue of electro-optic materials without causing any inconvenience while employing a bugger body type developing system.

[Brief explanation of drawings]

The drawings show an embodiment of the optical printer according to the present invention, FIG. 1 is a schematic configuration diagram, FIG. 2 (A) or C) is a potential model diagram from charging to development, and 3M is a perspective view of PLZT. Figure 4 is a block diagram of the drive device, Figure 5 is a time chart of recording operation, Figure 6 is a graph of the relationship between drive voltage and amount of transmitted light, and Figure 7 is a graph of the relationship between optimum voltage and duty ratio. be. (1)... Light source, (5)... Window light body.

Claims (1)

[Claims] A light modulation section having a plurality of electro-optic materials arranged in a row is provided between the charged photoreceptor and the light source, and a drive voltage for light modulation according to recorded information is applied to each of the plurality of electro-optic materials. a developing means for attaching toner to a portion of the photoconductor where charges disappear due to light irradiation; An optical printer comprising an optical fatigue compensating means for applying an electric field to an optical material in a direction opposite to that during a recording operation and exceeding a development level so that the amount of transmitted light is such that the charge on the photoreceptor does not disappear.