JP2007304349A - Optical device and image forming device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device incorporating an optical device which has optical elements to prevent toner contaminations caused by condensed water droplets in an optical element configuration that the toner is not adsorbed in the condensed water droplets. <P>SOLUTION: This optical device has an optical element 38 to pass or reflect images and projects images with light and forms latent images on a surface to scan with light. The optical element 38 has an electric conductive section 47 of a predetermined impedance at least on the surface passing or reflecting images. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention uses an optical device that has a light emitting element such as an LD or an LED to illuminate an illuminated surface, an optical device that projects images from the illuminated surface illuminated by the light emitting element at different positions, and these optical devices. The present invention relates to an image forming apparatus such as a copying machine, a printer, a scanner, and a facsimile.

  An optical device that has a light emitting element such as an LD (laser diode) or LED (light emitting diode) and illuminates the illuminated surface, an optical device that projects an image from the illuminated surface illuminated by the light emitting element at different positions, In image forming apparatuses such as copying machines, printers, scanners, and facsimiles using these optical devices, if the performance deteriorates due to the surface of the optical element becoming dirty, it is usually made dirty or difficult to become dirty. However, it is usual to configure so that the performance deterioration is reduced. If this cannot be achieved, the dirt is removed or the optical element itself is replaced.

There are several methods to make the surface of the optical element clean, or to make it difficult to get dirty, to block the path that leads to the occurrence of dirt, a layout that reduces the influence of gravity so that dirt is less likely to adhere (not horizontally laid), and a coating that is difficult to adhere. There is a method of applying etc.
There are methods for reducing performance degradation even if the surface of the optical element is dirty, such as a method of enlarging an image in the optical path and forming an image on the irradiated surface, a method of increasing the amount of light depending on the degree of contamination, and a method of performing image processing. Although there are many methods for removing the film, it can be said that it is an unnecessary function if the contamination is prevented within a range where the performance does not deteriorate.

When an element having a low normal temperature comes into contact with outside air having a higher temperature, dew condensation occurs on the surface of the element due to moisture contained in the outside air. On the other hand, as an image forming apparatus, electrophotography superior in productivity and handling property is generally spread, but the toner particles that have a great influence on the improvement of image quality from electronic parts are being miniaturized. Easily adsorbed to water droplets generated by condensation. For this reason, countermeasures against contamination with toner when the optical element is condensed is one of important techniques.
For this reason, a power supply device effective for preventing charge wire contamination and a technology for preventing contamination of the optical system by a technology for adsorbing floating toner using electrostatic adsorption are also known (see, for example, Patent Document 1). .
In the toner image forming apparatus of Patent Document 1, a technique for preventing contamination of an optical system by a technique for adsorbing toner floating around an optical element using electrostatic adsorption is disclosed.
JP-A-8-244277

However, in the prior art of Patent Document 1, there is a problem that toner particles are easily adsorbed to water droplets generated by condensation, and no countermeasure is taken against contamination of the optical element caused by the toner.
SUMMARY OF THE INVENTION An object of the present invention is to provide an optical device having an optical element that prevents contamination caused by toner caused by water droplets generated by condensation by configuring the optical element so that toner particles do not adsorb to water droplets generated by condensation. An image forming apparatus is provided.

In order to solve the above-described problems, an optical device according to a first aspect of the present invention is an optical device having an optical element that transmits or reflects light, wherein the optical element includes at least a light transmission surface and a reflection surface. A conductive portion having a predetermined impedance is provided on the surface.
According to a second aspect of the present invention, in the first aspect of the present invention, the apparatus includes a current supply unit that supplies a predetermined current to the conductive portion.

According to a third aspect of the present invention, in the first or second aspect, the optical element includes a conductive portion at least on a light transmitting surface and a reflective surface, and bias applying means for applying a predetermined bias to the conductive portion. It is characterized by that.
An image forming apparatus according to a fourth aspect of the present invention includes the optical device according to any one of the first to third aspects.
In addition, it is possible to prevent the suspended matter from adsorbing to the optical element, and not only greatly increase the maintenance interval in an optical device that requires regular maintenance, but also realize maintenance-free and cleaning mechanism-less. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is a technique for preventing the floating matter from adhering to the surface of the optical element of the condensed optical device. However, in the image forming apparatus, it is specified that the main floating matter causing contamination is toner. Thus, a configuration example of four typical optical devices among the optical systems used in the image forming apparatus will be described.
FIG. 1 is a schematic perspective view showing a general laser diode unit with a part thereof cut away. In this laser diode (hereinafter referred to as LD) unit A, a glass plate 2 is disposed on the upper surface of the cap 1, a laser (LD) chip 4 is disposed on the heat sink 3, and a PIN chip 6 is disposed on the stem 5 surrounded by the cap 1. It has a configuration.

As shown in FIG. 1, the LD unit A is composed of a clad layer and an active layer, and the laser light is emitted from the LD chip through the glass plate 2 by the electric charges from the electrodes connected to the clad layer (this is the Called the front beam a).
At this time, the back beam b paired with the front beam a is emitted to a photodiode (hereinafter referred to as PD) (not shown) in the LD unit A, and a PD output can be obtained from the electrode. As a result, the amount of beam light can be monitored, and a stable output with a predetermined optical power can be achieved by performing control according to the monitor output.

  FIG. 2 is a schematic perspective view showing the image forming apparatus system. FIG. 3 is a schematic perspective view showing an optical scanning device mounted on the image forming apparatus of FIG. FIG. 4 is a schematic view showing an image forming unit mounted on the image forming apparatus of FIG. The image forming apparatus system B in FIG. 2 is configured by connecting an image forming apparatus 7, a personal computer 8, and a facsimile 9 to the image forming apparatus 7.

An optical scanning device using a laser diode (hereinafter referred to as LD) will be described with reference to FIG. The optical scanning device C includes an LD unit A, an optical element that shapes the beam diameter of the laser light emitted from the LD unit A and guides it to the surface to be scanned, and a control unit that controls the LD light.
3, the writing unit of the exposure unit of the optical scanning device C includes a light emitting element (LD chip 4) of the LD unit A of FIG. 1, a polygon mirror 10 which is an optical element, an fθ lens 11, a folding mirror 12, a mirror 13, 13a and a cylindrical lens 14, a synchronization detection sensor 15 that performs synchronization detection to generate LD emission timing, and a scanning optical system that exposes a plurality of beams on a surface of the photosensitive drum 16 that is a surface to be scanned at predetermined intervals. It is shown.

The image forming unit D shown in FIG. 4 of the general image forming apparatus 7 in FIG. 2 performs a charging, exposure, development, transfer, and cleaning process around the photosensitive drum 16 that forms a latent image. 17, a developing device 18, a transfer device 19, a cleaning device 20, and a static elimination device 21.
Although not shown, the image forming apparatus 7 in FIG. 2 feeds a transfer sheet for forming an image, a fixing unit for fixing the transferred image, and a discharge unit for discharging the fixed transfer sheet. It has a paper section.
The image forming apparatus 7 forms an image using image data read by a scanner 21 or a digital camera, image data created on a personal computer (PC) 8 or image data of a facsimile 9 received via a telephone line. A latent image is formed by an LD control unit through an image I / F unit for inputting data and an image processing unit for accumulating, editing or processing the input image data. As an image forming apparatus having a plurality of light emitting elements, there are an image forming apparatus having a plurality of LD units and an image forming apparatus having an LD unit using an LD array.

FIG. 5 is a schematic view showing an image forming apparatus using an LED printer head. FIG. 6 is a schematic perspective view showing an LED printer head which is an optical scanning device mounted on the image forming apparatus of FIG. FIG. 7 is a schematic partial perspective view showing an example of a SELFOC lens mounted on the image forming apparatus of FIG.
Next, a configuration example of an image forming apparatus equipped with an optical writing device using an LED printer head (hereinafter referred to as LPH) will be described. 5 to 7, first, the image forming apparatus 7 in FIG. 5 includes a charging device 17, a developing device 18, a transfer device 19, a cleaning device 20, a static eliminating device 21, a toner 22 in the developing device 18, a separation device 23, and a fixing device. A device 24 and a stacker 25 are included.

Further, the image forming apparatus 7 includes an LPH 26 in which a plurality of integrated LED chips are arranged as shown in FIG. The LPH 26 includes an LED array element 29 on the back side of the substrate 28, an equal magnification lens 30, a heat radiating plate 31, a driver element 32 on the upper surface of the substrate 28, and an I / F unit 33.
Further, the image forming apparatus 7 includes a selfoc lens array 27 shown in FIG. The LPH 26 of the image forming apparatus 7 in FIG. 5 has a configuration in which a plurality of integrated LED chips 29 are arranged and imaged by the Selfoc lens 27, so that the configuration is simple compared to the optical scanning device in FIG. Because of its easy space, it has been used in facsimiles and printers.
However, since the light quantity of the LED itself is small and it is difficult to increase the degree of integration, the response to the recent increase in density is delayed. Further, since the individual LEDs have variations, light amount correction is necessary.

The light emission method is roughly classified into a strobe method and a dynamic method. In the strobe method, LEDs are turned on all at once by a strobe signal after light emission data is transferred to each LED.
In order to reduce the data transfer rate and to prevent a change in input current when the LED is lit, it is common to divide the strobe. On the other hand, the dynamic method has a merit that the control circuit is complicated, but individual LEDs are dynamically lit, so that the change in input current is small.

FIG. 8 is a schematic view showing an image forming apparatus equipped with an image reading apparatus using a reduction optical system. Next, a configuration example of an image reading apparatus using a reduction optical system will be described with reference to FIG.
As shown in FIG. 8, the image reading unit of the image forming apparatus 7 irradiates the original 37 on the contact glass 36 with light from the light source 35 and the reflecting mirror that converges the light from the light source. And a first mirror 38 that folds the reflected light image from the document 37.
Further, the image reading unit has a configuration in which the image from the first mirror 38 is folded back with the second mirror 39 and the third mirror 40, passes through the lens 41, and forms an image on the reading sensor 42.

The reading sensor 42 is generally a CCD sensor, and there are a one-line sensor used in monochrome and a three-line sensor used in color. In many cases, color scanning is performed using a one-line sensor by scanning a plurality of times while changing the wavelength of the light source 35. Currently, the use of images to a PC has progressed, so it is read as RGB information. As the light source 35, xenon or a fluorescent lamp is used.
In the case of a three-line sensor, the image processing unit 43 requires a memory (not shown) for correcting the distance between the sensors. Further, depending on the basic reading conditions (scanning speed / reading density), the distance between the sensors is set to a predetermined distance (an integer multiple of the pixel size on the sensor) under the conditions.
When the color is realized by switching the light source 36 with one line sensor, it is not necessary to correct the distance between the sensors, but an image memory that accumulates at least two reading regions is necessary.

In the image forming apparatus of FIG. 8, the electrical signal from the image processing unit 43 enters the optical writing optical system 44 in the printer unit, exposes the photosensitive drum 16, and develops the electrostatic latent image on the photosensitive drum 16 into a developing device. The image is developed at 18, transferred onto the transfer paper by the transfer device 19, and the transfer paper onto which the image has been transferred is thermally fixed by the fixing device 24 and discharged outside the apparatus.
FIG. 9 is a schematic view showing an image reading apparatus using a 1 × optical system mounted on the image forming apparatus. As shown in FIG. 9, the image reading apparatus includes a white light source 35 that irradiates a document 37 on a contact glass 36, an equal magnification sensor 45, and an equal magnification lens 46. A selfoc lens is generally used as the 1 × lens.
Since the image reading apparatus having this configuration has a larger pixel size than the reduction optical system, a MOS sensor can be generally used in addition to the CCD sensor. Furthermore, since the pixel size is large, the sensitivity of the sensor can be increased, and since the optical path length is short due to the equal magnification lens 46, the light amount of the light source 35 can be reduced. Organic EL etc. are also used.

FIG. 10 is a schematic perspective view showing a part of the mirror of the optical device. FIG. 11 is a schematic circuit diagram for explaining bias application. A method for applying a bias to the optical element of the above-described optical apparatus example will be described with reference to FIGS.
As an optical element for applying a bias, a mirror of the optical device, for example, the first mirror 38 in FIG. 8 has an aluminum vapor deposition layer (conductive portion) 47 formed by aluminum vapor deposition on its mirror surface.
The aluminum vapor deposition layer 47, which is the mirror surface of the mirror constituted by aluminum vapor deposition, is conductive, so that an electrode is formed by a presser leaf spring 48 and the like, and is grounded to GND by a housing (not shown). By maintaining insulation from a member (not shown), a desired bias (current) is applied to the surface of the optical element by bias application (current supply) from a power source (bias application means, current supply means) 51. Can generate heat. This heat generation can prevent the floating toner particles and the like from adhering.

As schematically shown in FIG. 11, the optical element (first mirror) 38 is grounded to GND via a housing (not shown) or the like, and a desired bias is applied to the surface thereof from a bias power source (bias applying means) 51. That is, it applies to the aluminum vapor deposition layer 47 (10).
For an optical element such as a lens made of glass or plastic, a bias can be similarly applied to the surface by coating the surface with a conductive polymer (polyethylenedioxythiophene or the like).
The impedance of the conductive portion 47 formed on the surface differs depending on the thickness and material of the coating portion (aluminum vapor deposition layer). However, in the case of the present invention, it is within a range in which a desired heat generation having a predetermined impedance characteristic and maintaining a temperature that does not cause dew condensation can be obtained by supplying a bias from the bias power source 51.

Although not shown, this temperature range where condensation does not occur can be easily realized by adding a switching function for switching the bias power supply 51 to be supplied and an insulating function for insulating the GND electrode.
The amount of heat generation can be controlled by impedance characteristics and current value, and a temperature at which condensation does not occur can be maintained. For safety, it is also possible to realize heat protection with a thermistor, a thermal fuse, a thermostat or the like.
In consideration of safety, the bias power supply 51 that supplies a bias is preferably realized by supplying a converter power supply using a general transformer, avoiding the primary power supply.

With the configuration described so far, by generating a temperature that does not cause condensation on the desired optical element, it is possible to prevent floating substances from adsorbing to the optical element, and maintenance is performed in optical devices that require regular maintenance. Not only can the interval be greatly increased, but also maintenance-free and cleaning mechanism-less can be realized.
In particular, such a configuration is an effective technique in a configuration in which maintenance is difficult due to space saving and miniaturization in recent years, and a configuration in which a cleaning mechanism cannot be provided.
In addition, in a system that normally does not have problems, contamination is a problem depending on the installation environment and installation application, and when it is added as a contamination prevention function, the configuration is simple, so quick actions are easy and user downtime (supply) (Paper time) can also be reduced.

It is a schematic perspective view which cuts and shows the structure of a general laser diode unit. 1 is a schematic perspective view showing an image forming apparatus system. FIG. 3 is a schematic perspective view showing an optical scanning device mounted on the image forming apparatus of FIG. 2. FIG. 3 is a schematic diagram illustrating an image forming unit mounted on the image forming apparatus of FIG. 2. 1 is a schematic view showing an image forming apparatus using an LED printer head. FIG. 6 is a schematic perspective view showing an LED printer head which is an optical scanning device mounted on the image forming apparatus of FIG. 5. FIG. 6 is a schematic partial perspective view showing an example of a SELFOC lens mounted on the image forming apparatus of FIG. 5. 1 is a schematic diagram illustrating an image forming apparatus equipped with an image reading apparatus using a reduction optical system. 1 is a schematic diagram illustrating an image reading apparatus using a 1 × optical system mounted on an image forming apparatus. It is a schematic perspective view which shows 1 part of the mirror of an optical apparatus. It is a schematic circuit diagram explaining bias application.

Explanation of symbols

  7 image forming apparatus, 13 optical element (mirror), 13a optical element (mirror), 26 LPH (LED printer head), 27 optical element (selfoc lens), 38 optical element (first mirror), 39 optical element (first) 2 mirrors), 40 optical elements (third mirror), 46 optical elements (same magnification imaging element), 47 conductive parts (aluminum deposition layer on transmission surface and reflection surface), 51 bias power source, 52 optical elements (mirror) 53 Optical element (mirror), A LD unit, C Optical scanning device

Claims (4)

  An optical apparatus having an optical element that transmits or reflects light, wherein the optical element has a conductive portion having a predetermined impedance on at least a light transmitting surface and a reflecting surface.   The optical apparatus according to claim 1, further comprising a current supply unit that supplies a predetermined current to the conductive portion.   3. The optical device according to claim 1, wherein the optical element has a conductive portion on at least surfaces of a light transmission surface and a reflection surface, and bias applying means for applying a predetermined bias to the conductive portion. apparatus.   An image forming apparatus comprising the optical device according to claim 1.

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