JPS6042459B2 - printing device - Google Patents

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to intermediate devices.

[Prior art]

FIG. 1 shows the configuration of the above-mentioned intermediate device.

Light is written onto the photosensitive drum 102 by an optical signal generating section 101 using a liquid crystal light valve. At this time, the photosensitive drum 102 is charged in advance by a corona charger 110. The optical signal at this time usually includes, for example, characters, in which light is generated corresponding to the part of the characters. This forms an electrostatic latent image, which is developed with toner by a magnetic brush developer 103. The development method used at this time is usually reversal development. Thereafter, the toner is transferred onto plain paper 104 by a transfer corona discharger 105 and fixed by a fixing device 106. Toner remaining on the photosensitive drum after transfer is
The electrostatic latent image is removed by the blade 108 and the electrostatic latent image is removed by the defrost lamp 10.
Defrosts at 9 and ends. FIG. 2 shows the configuration of the optical signal generator. The optical signal generating section consists of a light source 111 such as a fluorescent lamp, a liquid crystal light valve 150, and an imaging lens 115. The light emitted from the light source is modulated by a liquid crystal light valve. This optical signal 116 is imaged onto the photosensitive drum 102 by an imaging lens 115. A focusing optical fiber array is used as the imaging lens. As a result, an erect image is obtained. Figures 3 and 4 show the structure of the liquid crystal panel. Liquid crystal composition 12 between spacers 126
5 and is provided with polarizing plates 123 and 124 on both sides of a glass substrate. The common signal electrode is a transparent electrode 11
9 and an optically opaque metal electrode 120, and the signal electrodes 121 and 122 are transparent electrodes. The polarizing plates 123 and 124 are arranged so that their polarization planes are perpendicular to each other. The light is modulated by a microshutter formed by the transparent portion 119 of the common electrode and the signal electrode. In the text below, the shape of the transparent portion of the common electrode is sometimes expressed as a microshutter; in this case, a microshutter is formed together with the opposing signal electrode. The liquid crystal composition to be encapsulated is an optically active substance 4-(21 Methylbuty
1) A high-speed liquid crystal light valve can be obtained by using a long-period cholesteric liquid crystal obtained by adding 3% by weight of -4''-CyarlObiphenyls.

FIG. 5 shows the frequency characteristics of the dielectric anisotropy of this liquid crystal. The frequency at which the dielectric anisotropy is zero is called the crossover frequency and is represented by Fc. Let n be the frequency lower than FC and Fh be the higher frequency. The liquid crystal light valve operates by applying signals of frequencies f1 and Fh to each signal electrode. 6th
Figure b shows the response of the applied signal and the light transmitted through the liquid crystal light valve (a). Signal at time f1 indicated by T2, time F at T3
h signal is applied.

T1 is called a write period, T2 is called an opening time, and T3 is called a non-opening time. The liquid crystal light valve opens by applying the Fh signal, and closes by the 1 signal. By the method described above, we were able to obtain a revolutionary high-speed liquid crystal light valve. However, when such a conventional liquid crystal panel is used in a printing device, when the printing speed changes, it is necessary to prepare another liquid crystal panel corresponding to the change. There was a problem in that it was virtually impossible for the user to perform the exchange.

〔the purpose〕

The present invention overcomes the above-mentioned problems, and by using a four-digit common electrode and devising the arrangement and shape of the microshutter, it is possible to arbitrarily select between two modes: double speed and double density. The purpose is to provide a photographic device.

〔Example〕

FIG. 7 shows the electrode structure of a liquid crystal panel according to the present invention.

The difference from the conventional example shown in Fig. 4 is that the common electrode is 401,
There are four microshutters 402, 403, and 404, and there are four microshutters 406, 407, 408, and 409 for one signal electrode 405. Next, the driving method, which is the main point of the present invention, is shown in FIGS. 8 and 9.

A dedicated 1C with high breakdown voltage is used to drive the liquid crystal, but in the present invention, by performing 112 time-division drives, the number of drive 1Cs is not increased, and the reliability of high-density packaging is greatly improved. It produced an improvement effect. 9th
The figure shows the structure of the electrodes for explaining the principle of the 11-part driving method.
The micro shutters 424 and 425 are driven by this.

The signals to be applied are shown in FIG. 8, and the write speed is 11.
The common electrodes each take charge of the time Ta as a selection period. An 0N signal 410 and an 0FF signal 411 are applied as data signals to the signal electrode during the period Ta. 0
The N signal 410 is composed of a high frequency Fh during T2 and a low frequency n during T3, and the 0FF signal 411 is a low frequency n.

The common electrode signal 412 is composed of a signal having a phase opposite to that of the 0N signal 410 during the selection period, and a signal having a phase opposite to the 0FF signal 411 during the non-selection period, and the common electrode signals applied to the two common electrodes have different phases. It's off by half a cycle. Now, for example, if the common electrode signal 412 is applied to the common electrode 421, and the ON signal and 0FF signal for the period T1 are applied to the signal electrode 423, the signals applied to the microshutter 424 will be 413 and 414, respectively. The photoresponses of the microshutters are 415 and 416, respectively.

As shown here, the liquid crystal light valve in the present invention is
Both the common electrode and the signal electrode transmit light only when high frequency is applied. Based on the above principle, a liquid crystal light valve having a high-speed, high-density mode according to the present invention will be explained with reference to FIGS. 7 and 10. First, in the high density mode, optical writing is performed using the first micro shutter bears 406 and 407.

A common electrode signal 430 is provided to the common electrodes 401 and 402, respectively.
, 431 is applied, and 0FF is applied to the common electrodes 403 and 404.
A low frequency wave 432 having a phase opposite to that of the signal is applied. When a signal 433 corresponding to the data is applied to the signal electrode 405, the microshutters 406, 407 and 408 each receive a signal 433 corresponding to the data.
Voltages 4, 435 and 436 are applied, and the microshutters 406 and 407 open and close during respective selection periods in response to the data signals, as described above. On the other hand, the second micro shutter bears 408 and 409, to which only low frequency waves are always applied to the common electrodes 403 and 404, remain completely closed. Therefore, at this time, it is as if the second row of micro-shutter bears 408 and 409 does not exist, and optical writing is performed using only the two rows of first micro-shutter bears 406 and 407. Micro shutter 406 and 40
7 are arranged in a staggered pattern, and one line's worth of printing is performed using two micro-shutter arrays. Now, set the interval between the micro shutters 406 and 407 to 11, and write cycle to T.
l, if the photoreceptor moves at a speed V1 in the direction of the arrow in FIG.
Since the opening and closing will be repeated every 7fV1, in order for the written adjacent dots to line up on a straight line, 11 = (
m+112)×T,×V1(m=0,1,2...
must meet the requirements. As described above, since the 1-h time division driving method is used, microshutters with twice the density as shown in FIG. 4 can be driven with the same number of signal electrodes. Next, in the high-speed mode, the first micro-shutter bears 405 and 406 are closed, and the second micro-shutter bears 407 and 408 perform optical writing. Common electrode 401
, 402, a low frequency 432 is added to the common electrodes 403, 402.
Common electrode signals 430 and 431 are added to 04, respectively.
Therefore, this time the first micro shutter bear 406,4
07 is closed and the second micro shutter bear 408,4
09 opens and closes during each selection period. The microshutters 408 and 409 are on the same straight line in the direction of movement of the photoreceptor, that is, in the sub-scanning direction, and print one line alternately.

Therefore, the printing density is half that of the above-mentioned high-density mode, so in order to perform high-quality recording, the second micro-shutter bears 408 and 409 have a larger micro-shutter area than the first one. There is a need to. On the other hand, in the high-density mode, one line is written at the line scanning speed T1, whereas in the high-density mode. In mode, 2 at time T1.
Since line writing is performed and the recording density is halved, the recording speed is ultimately four times faster than the high density mode. Therefore, if the moving direction of the photoreceptor in the high-density mode is ■, then the interval 12 between the micro shutters 407 and 408 is 12=4nVT1 (n=1, 2, 3...
) is fine. Next, an embodiment and a drive circuit will be described.

This invention is 16.7 dots/W1! ! t and 8.3
Dot/T! We made a prototype of n. Repetition period T1=2n1
SeC, Yotsute■=3C! Considering the ease of making an n/Sec panel, m = 2 and n = 1, so 11 =
150 pm, 12=240 μm. FIG. 11 shows the drive circuit. A selector 501 selects a mode between double density and double speed. Data request lock from control unit 502, 2mse when in double density mode
c to the external time-series pixel signal generator 510 every 1 msec in high-speed mode, and sends it to the data selector 503.
Receives data that is cycled by the request clock. In the high-density mode, one line of received data is divided into two parts, one of which is distributed to the shift register 505 and the remaining part to the data buffer memory 504. The data stored in the memory 504 is delayed by two cycles and sent to the shift register 505 alternately every half cycle with the data directly output from the data selector. After the data entered in the shift register 505 is transferred, it is latched by a latch 506.
Depending on the latched data, the signal selector 507 outputs an 0N signal 511 or an 0FF signal 512. In the high-speed mode, the input data is alternately sent one line at a time, data is sent directly to the shift register 505 and data is sent to the memory 504, and data delayed by 2 msec and data not delayed are alternately transferred to the shift register 504. Then, one line is written at a speed of 1 msec.

508 is a signal generation section, which generates 0N signal 511, 0FF signal 5
12. Generate common electrode signals, etc.

In addition, the printing system other than the optical writing section has two promos speeds, and the speeds can be switched between ■ and 4V depending on the mode selection.

〔effect〕

As described above, the present invention has a 1-digit microshutter array and a 2-digit microshutter array.
The micro-shutter rows of digits are arranged in a staggered manner, the micro-shutter rows of digits of 3 and 4 are arranged parallel to the moving direction of the photoreceptor, and the micro-shutter rows of digits of 3 and 4 are arranged in a staggered manner.
, 4 digits, the opening area of each micro shutter is 1, 2
Since the opening area of each micro-shutter is on the order of magnitude larger than Even at high speeds, sufficient optical information can be transmitted onto the photoreceptor of the printing device.

[Brief explanation of the drawing]

FIG. 1 shows an example of the configuration of a printing device using a liquid crystal light valve. FIG. 2 shows an example of the configuration of an optical signal generator using a liquid crystal light valve. 3 and 4 show the structure of the liquid crystal panel. FIG. 5 shows the frequency characteristics of dielectric anisotropy of the liquid crystal material used in the present invention. FIG. 6 shows the response characteristics of the liquid crystal material used in the present invention and the driving signals at that time.
FIG. 7 shows the electrode shape of a liquid crystal panel having a high-speed, high-density mode according to the present invention. FIG. 8 shows the drive waveform and optical response of the time division drive method adopted in the present invention. FIG. 9 shows an electrode configuration for time-division driving. FIG. 10 shows drive waveforms for realizing the double-speed, double-density mode of the present invention. FIG. 11 shows a drive circuit according to the present invention. 10
1... Optical signal generation unit, 102... Photosensitive drum, 103... Developer, 105... Transfer device, 110... Charger, 106...
Fixing unit, 111...Light source, 112...
Liquid crystal panel, 113... Drive circuit, 115...
...Imaging lenses 401, 402, 403, 404 are common electrode signals 1, 2, 3, 4, 406, 407, respectively
・・・・・・First Micro Shutter Bear, 408,
409...Second Micro Shutter Bear.

Claims (1)

[Claims] 1 A liquid crystal is sealed in a pair of transparent substrates, four common electrodes are formed on one side of the substrates, and a plurality of signal electrodes are formed on the other side, and each signal electrode is arranged to cross the common electrodes. As a result, in a printing device having a photoreceptor that moves in a direction perpendicular to the longitudinal direction of a common electrode and a liquid crystal light valve in which a four-digit number of micro-shutters are formed, a micro-shutter row of one-digit number and two micro-shutter arrays are used. The micro-shutter rows of the 3rd and 4th digits are arranged in a staggered manner, and the microshutter rows of the 3rd and 4th digits are arranged parallel to the moving direction of the photoreceptor. The printing device is characterized in that the opening area of each micro-shutter is larger than the opening area of each micro-shutter of the 1st and 2nd orders of magnitude.