JPS61181666A - Optical head for electronic photograph type printer - Google Patents

Abstract

PURPOSE:To improve the life and rising of filaments by reducing the consumption of power by utilizing temperarure radiation of good luminous efficiency. CONSTITUTION:The drive energy of writing period T is represented by W.T/a, where a is a constant, for both cases, which almost equals to heat to be conducted in the form of Joule heat through a base plate 10, wirings 13 and 14, and a protective layer 12 to the outside of a filament array head 9 for consumption. The heat quantity to be conducted to the outside is, however, about several watts for the whole of head if the base plate 10 and the protective layer 12 made of a material of low thermal conductivity are adopted. When the temperature of the luminous portion 9a is controlled to 1,500 deg.K or more, conversion rate to effectively radiation flux becomes 1% or more. Also, since a heat-insulating structure is used, the irradiation of light can be made with lesser power consumption. Under no light irradiation condition, since the temperature difference of the luminous portion 9a during non-light irradiation period can be lessened because the temperature is kept constant at about 1,250 deg.K. The service life and rising of the luminous portion canthus be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical head for an electrophotographic printer.

[Conventional technology]

Writing optical heads used in conventional electrophotographic printers include laser beam scanners, LED array heads, liquid crystal shutter array heads, and the like.

[Problem that the invention seeks to solve]

The above laser beam scanner is a system that combines mechanical scanning with a polygonal mirror 71 and an optical system with an f/theta lens, and has drawbacks such as a large optical head and a short start-up time of several seconds. There is.

LED array heads and liquid crystal shutter array heads have the advantage of electronically controlled scanning and do not require mechanical scanning or short start-up time; however, in the case of LED arrays,
Luminous efficiency is low, with light output being 1% or less relative to input power. Further, in the case of a liquid crystal shutter array head, since the light flux is controlled from the outside, the incidence of light from an external light source is extremely low, and is substantially less than 1%. Therefore, conventional electronic scanning optical heads require large amounts of power to obtain a sufficient amount of light.

[Means for solving problems]

In the present invention, a thin film pattern made of a heat generating resistor is arranged on a substrate to form an optical head, and when a current is passed through the thin film pattern, temperature radiation caused by Joule heat is generated to expose an opposing photosensitive drum to perform printing. It is characterized in that the temperature of the light emitting part is maintained at a temperature at which the amount of light exposure can be ignored.

[Effect]

According to the above configuration, by setting the temperature of the light emitting part to 1500 or higher, an exposure amount that satisfies the sensitivity of the photosensitive drum having photosensitivity in the long wavelength band is given, and when it is not exposed to light, the temperature is kept at about 1250 and the photosensitive drum is By generating an exposure amount less than the photosensitivity of , power consumption is reduced, the start-up Dt of the light emitting part is improved, and the life of the light emitting part is extended.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view, and in the figure, 1 is a photosensitive drum that rotates in the direction of the arrow. 2 is a charger, 3 is a developer,
Reference numeral 4 denotes a transfer device, and 5 denotes a cleaner, which are similar to those used in commonly used electrophotographic processes and are arranged in sequence as described above.

A recording paper 6 transfers a toner image by a transfer device 4 and passes through a fixing plate 1 . 8 is a rod array lens.

9 is a filament array head, which has a thin film pattern 1 made of a heating resistor on a substrate 10 with low thermal conductivity such as reed or glass.
1 was prepared and covered with a protective layer 12. Infrared rays and near-infrared rays are emitted from the thin film pattern 11, the protective layer 12 of the thin film pattern 11, and the substrate 10 in the vicinity of the thin film pattern 11 to form a radiation portion 9a.

FIG. 2 is a plan view of a thin film pattern, in which a plurality of light emitting parts 9 are shown.
A is made of tantalum, for example, and the other wiring parts have a high resistance value, and when energized, they become high in temperature due to the heat generated by the electric current, causing temperature radiation. Both ends of each light emitting section 9a are connected to a common electrode 13 and a terminal 14 corresponding to each light emitting section 9a, and the terminal 14 is connected to a driver circuit (not shown). By controlling this driver circuit according to the print signal, the driving of the light emitting section 9a is controlled.

The photoreceptor of the photoreceptor drum 1 is an organic photoconductor layer having photosensitivity in the range of 700 to 950 nm, for example, a photoreceptor layer having a carrier generation layer made of a butalocyanine compound.

FIG. 3 is a graph showing the spectral distribution curve of a black body, and also shows the sensitivity range of the photoreceptor of the present invention.

Thermal radiation is shown for cases of 1500 and 1250, but in the case of 1500, the effective radiant flux entering the sensitivity region is approximately IX of the total radiant flux. Similarly, in the case of 1250, it is about 0
．． It becomes 1%.

The driving method of the present invention will be explained according to FIG.

FIG. 4I is a graph of the motive power of the light-emitting part, 2 is the temperature of the light-emitting part, and 2 is the graph of the effective radiant flux. The horizontal axis is the same time axis for I, n, and III.

The drive power is set so that the drive energy for exposure and non-exposure is equal for the writing period T. However, in the exposure data, W is set for each light emitting part 9a of the filament array head.
The power is driven for T/a time, and W for non-exposure data.
/a power is operated for 1 hour. The drive energy of the write period T is W·T/a in both cases. However, a is a constant. This driving energy is approximately equal to the amount of heat that is converted into Joule heat, conducted through the substrate 10, the wirings 13, 14, and the protective layer 12t, and consumed to the outside of the filament array head 9. However, if the substrate 10 and the protective layer 12 are made of a material with low thermal conductivity, the amount of heat conducted to the outside will be approximately several watts for the entire head.

In the write cycle where data is not exposed, the light emitting part temperature is 1
Drive energy W-T/ is maintained at about 250.
a is adjusted. When the temperature of the light emitting section is about 1250, the effective radiant flux is an exposure amount that can be ignored with respect to the sensitivity of the photoreceptor.

In the case of exposure, since the driving power is concentrated at l/a of the writing period T, the temperature of the light emitting part 9a is higher than 1500° C., and the effective radiation flux can provide sufficient exposure for the sensitivity of the photoreceptor. The driving power has a pulse width of T/a and becomes zero thereafter. At this time, the temperature of the light emitting part 9a decays exponentially, and at the end of the writing cycle, the temperature reaches 1250.
Return to degree.

Therefore, the effective radiant flux also tails, making it possible to provide sufficient exposure for the sensitivity of the photoreceptor.

In the present invention, the area around the light emitting section 9a is made into a heat insulating structure, the driving energy of the writing period T for exposure and non-exposure is set to be approximately equal, and the amount of heat conducted from the light emitting section to the outside is approximately equal to this driving energy. Therefore, the temperature of the light emitting part 9a can remain at the set value even if exposure and non-exposure writing appears irregularly, and the intensity of the effective radiant flux and the exposure amount can also be maintained at a constant value. I can depend on it.

In addition, stable exposure can be performed by detecting the temperature of the light emitting part using a temperature sensor (not shown) with a slow response speed and controlling the above average power consumption so that the detected temperature is constant over a response time of several seconds. Ru.

In the present invention, the temperature of the light emitting part 9a'! If r1500 or more is set, the conversion rate to effective radiant flux will be 1% or more, and since a heat-insulating structure is adopted, exposure can be performed with low power consumption.

Furthermore, since the temperature is kept at about 1250 in the non-exposed state, it is possible to reduce the temperature difference of the light emitting part 9a between the non-exposed and exposed periods, which improves the life span and start-up of the light emitting part. can.

In the present invention, it is practical if the driving energy in the exposure period is within a range of approximately 0.5 to 2 times the driving energy in the non-exposure period. is practical if it is 1/2 or less of the period, and conversely, in non-exposure periods, the pulse width of the driving power is practical if it is 1/2 or more of the period.

The actual performance of the filament array head is
The pitch can be approximately several tens of meters, and the writing cycle can be approximately 1 ms.

〔Effect of the invention〕

According to the present invention as described above, the optical head utilizes temperature radiation with high luminous efficiency, and the temperature of the light emitting part is maintained around a certain temperature even during non-exposure, thereby reducing power consumption and increasing the lifespan of the filament. It is something that can be improved.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is a plan view of the filament array head, Fig. 3 is a graph of the spectral radiant flux of a blackbody, and Fig. 4 is a graph explaining the driving method. be. 9... Filament array head 9a... Light emitting section 10... Substrate 11... Thin film pattern 12...
Protective Layer Patent Applicant: Oki Electric Industry Co., Ltd. Agent, Patent Attorney: Takashi Kanakura @ 1 = @ 4 Voices; Procedural Amendment (Voluntary) July 3, 1985 Commissioner of the Patent Office Michibe Uga 1 , Indication of the case 1985 Patent Application No. 021863 2, Title of the invention Optical head 3 of an electrophotographic printer, Person making the amendment Relationship to the case Patent applicant address 1-7-12 Toranomon, Minato-ku, Tokyo Title (029) Oki Electric Industry Co., Ltd. Representative Nankai Hashimoto 4, Agent Specification "Claims column", "Detailed description of the invention column" 7. Contents of amendment 1, Patent Amend the scope of claims as shown in the attached sheet. 2. Correct "Fuser plate 7" on page 4, line 19 of the specification to "Fuser 7". 3. Correct "8 is a rod array lens" on page 4, lines 19 and 20 of the specification to "8 is a rod lens array." 4. Change "to make it good" on page 9, line 14 of the specification to "
``To make it good.'' Claim 1: A light-emitting portion that emits temperature radiation is formed, and drive energy is applied to the light-emitting portion even during a write period in which data is not exposed to maintain the temperature of the light-emitting portion at a temperature where the amount of exposure can be ignored. Features of the optical head of electrophotographic printers. 2. Claim 1 is characterized in that the driving energy given to the light emitting part during the writing period when data is not exposed is set to be approximately equal to the amount of heat conducted from the light emitting part to the outside of the light emitting part. Optical head for electrophotographic printers. 3. An electrophotographic type according to claims 1 and 2, characterized in that, in a writing cycle in which data is exposed, drive energy applied to the light emitting part is concentrated in a time of 1/2 or less of the cycle. Printer optical head. 4. An electrophotographic printer according to claims 1 to 3, characterized in that, in a writing cycle in which data is not exposed to light, the driving energy applied to the light emitting part is dispersed over a period of time 172 or more. optical head. 5. In claims 1 to 4, the driving energy applied to the light emitting unit during a writing cycle in which data is exposed is 0.5 times the driving energy applied to the light emitting unit in a writing cycle in which data is not exposed. An optical head for an electrophotographic printer, characterized in that the optical head is twice as wide as the optical head.

Claims (1)

[Claims] 1. A thin film pattern is arranged on a substrate to form a light emitting part,
An optical head for an electrophotographic printer, characterized in that the temperature of the light emitting part is maintained at a temperature at which the amount of exposure can be ignored by applying driving energy to the light emitting part even in a writing period when data is not exposed to light. 2. Claim 1 is characterized in that the driving energy given to the light emitting part during the writing period when data is not exposed is set to be approximately equal to the amount of heat conducted from the light emitting part to the outside of the light emitting part. Optical head for electrophotographic printers. 3. An electrophotographic type according to claims 1 and 2, characterized in that, in a writing cycle in which data is exposed, drive energy applied to the light emitting part is concentrated in a time of 1/2 or less of the cycle. Printer optical head. 4. An electrophotographic device according to claims 1 to 3, characterized in that in a writing cycle in which data is not exposed to light, the driving energy applied to the light emitting part is dispersed over a period of 1/2 or more of the cycle. Optical head for type printer. 5. In claims 1 to 4, the driving energy applied to the light emitting unit during a writing cycle in which data is exposed is 0.5 times the driving energy applied to the light emitting unit in a writing cycle in which data is not exposed. An optical head for an electrophotographic printer, characterized in that the optical head is twice as wide as the optical head.