JPH09277596A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a focus shift in an optical system due to the heating of an exposure device or a color shift when a colored image is formed from occurring by maintaining the strength and ease of perfect assembling of an image former. SOLUTION: This image forming device consists of an exposure light source with LED 110 arranged linearly on a substrate 140 and an exposure optical system with an image forming element for forming an image on the face of an image former 1 with a beam from the exposure light source, formed internally in the image former 1. In addition, the image former 1 is formed with a thickness of 1-8mm and the distance between the inner face of the image former 1 and the end face of the image forming element is 0.5-10mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer and a facsimile, and more particularly, a plurality of chargers, an image exposing device and a developing device are arranged around an image forming body. The present invention relates to an image forming apparatus that forms a color image by superposing toner images during one rotation of the image forming body.

[0002]

2. Description of the Related Art As an example of an image forming apparatus adopting an electrophotographic method for forming a multicolored color image, a color image is formed by sequentially performing charging, image exposure and development for each color within one rotation of one photoconductor. An apparatus for forming the has been proposed. Such an image forming apparatus enables high-speed image formation. However, it is necessary to dispose a plurality of sets of a charging device, an image exposing unit, and a developing device within one circumference of the photoconductor, and there is a possibility that the image leaks from the toner leaking from the developing device adjacent to the optical system for performing the image exposure to deteriorate the image quality. However, in order to avoid this, there is a technical problem such as a contradiction that the distance between the image exposure means and the developing device needs to be large, and the diameter of the photoconductor is inevitably large and the device is large. It was

In order to avoid such a technical problem, the base of the image forming body is formed of a light-transmissive material, and a plurality of image exposing means are housed therein, and an image is transmitted through the base to form an image. An apparatus has been proposed in which a photosensitive layer formed on the outer periphery of a formed body is exposed (JP-A-5-307307, etc.).

Such an image forming apparatus (Japanese Patent Laid-Open No. 5-3073)
No. 07) is capable of forming a color image while the image forming body is rotated once, so that the image recording time can be shortened and high-speed recording can be performed, and it is also effective for improving the image quality. In addition, inside the image forming body composed of a translucent substrate and a photosensitive layer,
There has been proposed an apparatus of a type in which a linear image exposure unit for each color is arranged (hereinafter referred to as an optical system inclusion type). The image forming apparatus having the optical system-containing exposure unit has an advantage that the image forming body can be downsized and the apparatus can be configured compactly.

[0005]

In the image forming apparatus having the linear image exposing means for each color in the image forming body, the thickness of the translucent substrate is increased in order to increase the strength of the image forming body. When,
The distance from the end surface of the imaging element to the imaging surface (hereinafter, abbreviated as working distance) inevitably becomes long. When such a working distance becomes long, the equivalent F value of the image forming element becomes small, so that in order to form a proper latent image, the light emitting element needs to emit light strongly. However, if such a configuration is adopted, the amount of heat generated from the exposure optical system increases, the exposure optical system becomes hot, and the holding member or the like is deformed, which causes a shift in the writing position and a decrease in brightness. Technical issues arise. In addition, it hinders downsizing of the device. On the other hand, the shift of the writing position due to the increase in heat generation,
If an imaging element having a short working distance is used to suppress the decrease in brightness, the exposure optical system may be brought into contact with the inner surface of the image forming body when the image forming apparatus is assembled.
These mean that it is necessary to find the optimum values of the thickness and working distance of the image forming body that can simultaneously achieve the above-mentioned technical problems.

An exposure light source in which light-emitting elements such as LEDs are linearly arranged generally causes the light-emitting elements and driving ICs of the light-emitting elements to generate heat when turned on for image exposure. Due to such heat generation, the temperature inside the machine rises. On the other hand, since the depth of focus of the gradient index lens array generally used in the exposure optical system is extremely shallow, the image forming body and the light emitting element of the exposure optical system are held by the heat generated by the light emitting element or the exposure element to increase the temperature inside the machine. Due to the deformation of the members and the like, a deviation occurs on the image forming surface of the exposure optical system, which causes a technical problem that an unclear image is formed due to the focus deviation.

On the other hand, there is an image forming apparatus that forms a toner image of a plurality of colors by superimposing them while the image forming body is rotationally transferred, includes an exposure device for each color. Full color can be reproduced, for example, in yellow, magenta, cyan, and black. Generally, when an exposure light source in which light emitting elements are linearly arranged on a substrate is turned on for image exposure, the light emitting elements and the ICs for driving the light emitting elements generate heat. When the temperature of the substrate rises due to such heat generation, the temperature rise due to heat generation causes the substrate to deform and the imaging position of each exposure optical system to shift. There is a technical problem that a color shift occurs in a color image due to such a phenomenon.

In view of the above technical problems, a first object of the present invention is to provide an image forming apparatus which retains the strength of the image forming body, suppresses heat generation from the exposure apparatus and is easy to assemble.

In view of the above technical problems, a second object of the present invention is to provide an image forming apparatus capable of forming a focused and clear image.

In view of the above technical problems, a third object of the present invention is to provide an image forming apparatus capable of suppressing color misregistration and forming a color image.

[0011]

The above object can be achieved by the following constitutions.

In the image forming apparatus described in (1) to (3), the optimum thickness of the image forming body and the optimum value of the distance between the inner surface of the image forming body and the end surface of the image forming element forming the exposure optical system are specified. By doing so, the strength of the image forming body can be maintained, the increase in the amount of heat generated from the exposure device, the deviation of the writing position, and the decrease in brightness can be suppressed, and the strength of the image forming body can be maintained for easy assembly. Yes, specifically, the following configurations are provided.

(1) An exposure optical system provided with an exposure light source in which light emitting elements are linearly arranged on a substrate and an imaging element for forming an image of a beam from the exposure light source on the surface of an image forming body and performing image exposure. Is disposed inside the image forming body, wherein the image forming body is formed to have a thickness of 1 to 8 mm, and the distance between the inner surface of the image forming body and the end surface of the imaging element is 0.5. -10m
An image forming apparatus, wherein the image forming apparatus is m.

(2) The image forming apparatus according to (1), wherein a light emitting diode is used as the light emitting element and a gradient index lens array is used as the image forming element.

(3) The inner diameter φ of the image forming body is φ = 60
The image forming apparatus according to (1), which is about 180 mm.

In the image forming apparatus described in (4) to (6), the size and material of each part of the image forming body and the exposure optical system are changed even when the temperature inside the apparatus changes while the image forming apparatus is driven. Is formed on the image forming surface of the image forming apparatus, and an unclear image is formed due to the deviation of the focus position so that the image forming position deviates from the specified focus by 200 μm or less. Has the following configuration.

(4) Exposure in which an exposure light source in which light emitting elements are linearly arranged on a substrate and a beam from the exposure light source is formed on a surface of an image forming body and a gradient index lens array for image exposure is arranged An image forming apparatus having an optical system, characterized by satisfying the following formula.

[0018]

(Equation 4)

Here, ΔT1 is the fluctuation range [K] of the temperature in the vicinity of the light emitting element, R is the radius of the image forming body, and R is
i is the radial length [μm] of each member forming the exposure optical system in the radial direction of the image forming body, and α is the linear thermal expansion coefficient [° C. ^{−1 of the} translucent substrate forming the image forming body. ] And αi
Is the coefficient of linear thermal expansion of each member constituting the exposure optical system [° C.
^-1 ].

(5)

[0021]

(Equation 5)

The image forming apparatus according to (4) is characterized in that the image forming is stopped at the time of.

(6)

[0024]

(Equation 6)

The image forming apparatus according to (4), further comprising temperature control means for controlling ΔT1 so as to satisfy the above condition.

In the image forming apparatus described in (7) to (11), when the light emitting element is turned on, the substrate expands greatly due to the heat generated by the light emitting element itself or the IC for driving the light emitting element, and writing is performed by a plurality of sets of exposure optical systems. Since the positions are largely different, the color shift when forming a color image is suppressed to several tens of μm or less, and specifically, the following configuration is provided.

(7) An exposure light source in which light emitting elements are linearly arranged on a substrate, an exposure optical system for forming a latent image on an image forming body by the light from the exposure light source, and a plurality of developing means are provided. An image forming apparatus that forms an image by superimposing toner images on the image forming body by sequentially repeating formation of a toner image on the image forming body by the developing device after image exposure of the image forming body. An image forming apparatus satisfying the following formula.

ΑA × L × ΔT2 ≦ 1/2 pixel diameter [μm] where αA is the linear thermal expansion coefficient [° C. ^-1 ] of the material used to form the substrate, and L is the image formation on the substrate. The length in the body axis direction [μm], and ΔT2 is 2 of the temperature near the light emitting element.
It is a temperature difference [0] from 0 ° C.

(8) The substrate has a coefficient of linear thermal expansion of 20 ×
The image forming apparatus according to (7), which is formed of a material having a temperature of 10 ^-6 ° C ^-1 or less.

(9) The temperature in the vicinity of the light emitting element is 0 to 6
The image forming apparatus according to (7), which is used in the range of 0 ° C.

(10) The image forming apparatus according to (7), wherein image formation is stopped when αA × L × ΔT2> 1/2 pixel diameter [μm].

(11) The image forming apparatus according to (7), characterized in that the temperature control means for controlling ΔT2 is operated so as to satisfy αA × L × ΔT2 ≦ 1/2 pixel diameter [μm].

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an image forming apparatus and its image forming process in the following embodiments will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 1 is a sectional view showing a schematic structure of an image forming apparatus according to this embodiment, FIG. 2 is a perspective view of an image exposing apparatus according to this embodiment, and FIG. 3 is a main part of the image exposing apparatus. FIG. 4 is a sectional view, and FIG. 4 is a perspective view showing a substrate in which light emitting elements are linearly arranged.

The image forming apparatus according to the present embodiment is provided with a cylindrical image forming body 1, image exposing devices 11 to 14 are arranged inside the image forming body 1, and a charger 21 is provided on the outer periphery of the image forming body 1.
-24, developing devices 31-34, transfer device 41, separator 42,
The image forming process means of the fixing device 50 and the cleaning device 60 are arranged, and the paper feeding cassette 71, the paper feeding roller 72, the carrying roller 73, the carrying belt 74, the paper discharging roller 75, and the paper discharging tray 76 are arranged as the paper feeding mechanism. The structure is such that yellow, magenta, cyan, and black toner images are formed in a superimposed manner during one rotation of the image forming body 1, and the color toner images are transferred to the recording paper by the transfer device 41, and then the recording paper is transferred. Is separated from the image forming body 1 by the separator 42 and the conveyor belt 7 is separated.
The color toner image carried on the recording paper by the fixing device 52 is permanently fixed by the fixing device 52, and the recording paper is placed on the paper discharge tray 76 by face-up via the paper discharge roller 75. It is what is discharged. Before describing the outline of the configuration of each part, an outline of the color image forming process of the image forming apparatus according to the present embodiment will be described.

First, when the image recording is started, the drive motor (not shown) is rotated to rotate the image forming body 1 in the clockwise direction, and at the same time, the charging of the scorotron charger 21 arranged on the left side of the image forming body 1 is performed. By the action, application of electric potential to the image forming body 1 is started. After such a charging process, the image exposure apparatus 1
At 1, the exposure by the electric signal corresponding to the yellow image signal is started and the electrostatic latent image corresponding to the yellow image of the original image is formed on the photosensitive layer on the surface of the image forming body 1 by rotational scanning.

The electrostatic latent image formed on the image forming body 1 by the above-mentioned exposure process is subjected to reversal development in a non-contact state by the developer carried on the developing sleeve of the developing device 31 to form a yellow toner image. Make it visible.

Then, the image forming body 1 is rotated to
A potential is applied to the yellow toner image already carried on the image forming body 1 by the charging action of the charger 22, and the exposure device 12 performs the exposure with the electric signal corresponding to the magenta image signal. By non-contact reversal development by 32, a magenta toner image is sequentially formed on the yellow toner image.

By the same process, a cyan toner image is further superposed and formed by the charger 23, the image exposure device 13 and the developing device 33. Subsequently, a black toner image is sequentially formed by the charging device 24, the image exposure device 14, and the developing device 34, and a color toner image is formed on the peripheral surface of the image forming body 1 within one rotation. .

The transfer paper P is sent out from the paper feed cassette 71 and conveyed to the timing roller 77. The color toner image formed on the peripheral surface of the image forming body 1 is transferred to the transfer paper P that is fed in synchronization with the toner image on the image forming body 1 by driving the timing roller 77 in the transfer device 41. To be done.

The transfer paper P having the toner image transferred thereto is removed of the charge in the separator 42 and separated from the peripheral surface of the photoconductor drum, and is then conveyed to the fixing device 50 by a conveyor belt 74 which is a conveying means. It After being heated and pressure-bonded in the fixing device 50 to fuse and fix the toner on the transfer paper P,
The toner is discharged from the fixing device 50, is conveyed by a pair of paper discharging rollers, and is discharged via the paper discharging rollers 75 onto the paper discharging tray 76 at the upper part of the apparatus with the toner image surface facing down.

On the other hand, the image forming body 1 from which the transfer paper P is separated is cleaned by the cleaning blade 61 in the cleaning device 60.
Thus, the surface of the image forming body 1 is rubbed to remove and clean residual toner, and the toner image of the original image is continuously formed or is temporarily stopped to form a new toner image of the original image. The waste toner scraped off by the cleaning blade 61 and the cleaning roller 62 is discharged to the waste toner container 64 through the toner carrying screw 63 and a toner carrying pipe (not shown). After the cleaning is completed, the cleaning blade 61 and the cleaning roller 62 are kept apart from the image forming body 1 in order to prevent the image forming body 1 from being damaged.

The above is the schematic configuration of the color image forming process in the image forming apparatus of the present embodiment.

Then, the optimum values of the thickness and working distance of the image forming body and the deformation of the image forming body and the exposure optical system due to the rise of the temperature inside the machine due to the heat generation of the light emitting element and the exposure element form an image in the exposure optical system In the image forming apparatus equipped with a plurality of exposure devices, there is a technical problem that the surface is misaligned and an unclear image is formed due to the focus deviation. The image forming apparatus according to the present embodiment will be described with a focus on a configuration for solving the technical problem of causing a shift.

The image forming body 1 is formed by forming a cylindrical base body (referred to as a transparent base body) from a translucent member such as a translucent acrylic resin and transmitting light to the outer periphery of the translucent base body. Conductive layer, a-Si layer or organic photosensitive layer (OPC)
Is a cylindrical photosensitive drum on which a photosensitive layer is formed, and the external diameter φ is 80 mm and the thickness t is 3 mm by the centrifugal polymerization method. The image forming body 1 is grounded, is rotatably arranged in the center of the apparatus main body, and rotates clockwise in FIG.

Since the image forming body 1 in the present embodiment is image-exposed from the image exposing devices 11 to 14 disposed inside as described above, the light-transmitting substrate is a material that transmits light. Depending on the constitution, it is necessary to give an appropriate potential contrast to the photosensitive layer. However, the light transmittance of the substrate need not be 100%, and the image exposure devices 11 to 1
The characteristic may be such that a certain amount of light is absorbed when the beam emitted from No. 4 is transmitted. Such a transparent substrate is manufactured from an acrylic copolymer by a centrifugal polymerization method.

As a result, it is possible to manufacture a cylindrical substrate having a hardness comparable to that of aluminum and a light transmittance of 90% or more and impact resistance performance of about 15 times that of glass. In this way, the image forming body 1 has a linear thermal expansion coefficient α at 20 ° C. of 80 × 10 ⁻⁶ ° C. ⁻¹ . The linear thermal expansion coefficient α is the rate of change in length per 1 ° C of temperature (° C ^-1 ), and its measurement method is specified in JIS for each material. For example, JI
SK 7197 and the like.

If the inner diameter φ of the image forming body 1 is smaller than 60 mm, the peripheral length for arranging the process members described later cannot be obtained, while the inner diameter φ of the image forming body 1 is smaller than 180 mm. If the size is increased, the size of the entire device cannot be reduced.

The thickness t of the transparent substrate of the image forming body 1 is set to 1
If it is less than mm, it is not possible to obtain sufficient strength to withstand the distortion when the contact rollers of the developing devices 31 to 34 are contacted. If image exposure is performed in such a situation, the image exposure devices 11 to 11
The image shift occurs at 14. On the other hand, if the thickness t of the transparent substrate of the image forming body 1 is made larger than 8 mm, the light emission intensity from the light emitting element 110 must be increased.
The amount of heat generated from the light emitting element 110 and the driving IC 142 increases. When the amount of heat generation increases, as will be described later, the substrate on which the light emitting elements are arranged, the holding member that holds the SELFOC lens, and the like are deformed, causing a shift in the imaging position and a decrease in brightness. Therefore, the thickness of the translucent substrate is 1 mm to 8 mm.
Is preferable.

As a material for the substrate having a permeability satisfying the above-mentioned conditions, an acrylic resin, particularly a polymer obtained by using a methacrylic acid methyl ester monomer, is preferable because of its excellent transparency, strength, precision and surface property. Fluorine used for other general optical members, etc.
Various translucent resins such as polyester, polycarbonate and polyethylene terephthalate can be used.

As the conductive layer, a metal thin film made of indium / tin / oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, Au, Ag, Ni, Al or the like and maintaining a light-transmitting property. As a film forming method, a vacuum vapor deposition method, an active reaction vapor deposition method, various sputtering methods, various C
A VD method, a dip coating method, a spray coating method or the like is used. As the photosensitive layer, amorphous silicon (a-S
i) An alloy photosensitive layer, an amorphous selenium alloy photosensitive layer, or various organic photosensitive layers (OPC) can be used.

The image exposure apparatuses 11 to 14 include a light emitting element 110 linearly arranged in the axial direction of the image forming body 1 and a gradient index lens array as an image forming element (for example, SELFOC lens manufactured by Nippon Sheet Glass Co., Ltd.). (Hereinafter, abbreviated as SLA.) 120, a linear image exposing means in which the distance 1 between the inner surface of the image forming body 1 and the end surface of the image forming element of the exposure optical system is about 2 mm. Image exposure devices 11-14
The image forming body 1 is formed by centrifugal polymerization to have an outer diameter φ of 80 mm and a thickness t of 3 mm, and the distance 1 from the imaging element 120 to the inner surface of the image forming body 1 is set to an optimum range of about 2 mm. By suppressing the heat generation amount of the optical system to the optimum value, it is possible to suppress the shift of the writing position and the reduction of the brightness.

If the distance 1 between the image forming body 1 and the terminal surface of the SLA 120 is set to 0.5 mm or less, the chance of contact and damage during assembly of the apparatus increases. On the other hand, if the distance 1 is longer than 10 mm, the light emission intensity of the light emitting element 110 must be increased.
Also, there is a problem that the amount of heat generated from the driving IC 142 of the light emitting element 110 is increased.

In the present embodiment, the image exposure devices 11 to 1
Since 4 has the same structure, hereinafter, the configuration of each part will be described in detail with reference to FIGS.

As shown in FIGS. 2 and 3, the exposure apparatus 100 has a holding member for holding the light emitting element 110 arranged in the axial direction of the image forming body 1, the driving IC 142 for the light emitting element 110, and the SELFOC lens 120. The image forming apparatus 1 is mounted on an optical support 200 that is configured as a unit attached to the image forming body 1 and fixedly holds an exposure device provided inside the image forming body 1. The image signals of the respective colors stored in the memory are sequentially read from the memory. It is output and input as an electric signal to the exposure apparatus 100 for each color.

The light emitting element 110 has an emission wavelength within the range of 600 to 900 nm as shown in FIG.
This is an array in which (light emitting diodes) are linearly arranged, and for example, the coefficient of linear thermal expansion α2 at 20 ° C. is 3.6 × 10 ^−6.
It is formed on the substrate 140 using Pyrex glass whose temperature is ^-1 . Further, the SLA 120 is a small black circle in the figure, and the substrate 140 of the light emitting element 110 is fixed to the holding member 130 by an adhesive agent indicated by diagonal lines.

The SLA 120 is, for example, SLA-20 or SLA20 manufactured by Nippon Sheet Glass in order to shorten the focal length.
By adopting BS, the amount of light reaching the image forming body 1 is increased and the amount of light emitted from the light emitting element 110 itself is reduced. In this embodiment, the color shift amount D can be approximated by the following expression (1).

D = αA × L × ΔT2 (1) where αA is the coefficient of linear thermal expansion of the material used to form the substrate 140, and L is the substrate 14 as shown in FIG.
0 is the length in the axial direction of the image forming body, and ΔT2 is the light emitting element 1
It is a temperature difference from 20 ° C. in the vicinity temperature of 10. In general,
When forming a color image, it is said that a good image can be obtained if the pixel shift between the toner images is within a 1/2 pixel diameter. Here, the pixel diameter is 63.5 μm when the pixel density is 400 dpi, and 42.
3 μm. Therefore, the above-mentioned αA × L × ΔT2 ≦ 1
By satisfying / 2 pixels, it is possible to provide a color image forming apparatus capable of obtaining a good color image without color misregistration.

The image forming apparatus of this embodiment has a room temperature of 20.
If the color shift amount D is set to 0 at 0 ° C., and the temperature in the vicinity of the light emitting element 110 fluctuates within a range of 20 ° C. to 10 ° C. which is a normal use state, Δ
T2 is 10 ° C., and αA at 20 ° C. is 20 × 10
^{If -6} ° C. ^-1 and L is 240 mm corresponding to A4, the color shift amount D is about 50 μm from the formula (1), and if the size of one pixel is about 80 μm, the image forming apparatus of 300 dpi is The value of the coefficient of linear thermal expansion of the substrate 140 is 20 × 10 ^-6 ℃
If it is larger than ^-1, D≤1 / 2 pixel is not satisfied, and color misregistration becomes a problem.

The temperature in the vicinity of the light emitting element 110 is 0 ° C.
If it goes down further, the light emitting element will not operate normally, and conversely 6
If the temperature exceeds 0 ° C., the color misregistration amount D becomes too large. Such temperature may occur when the image forming apparatus is continuously used. Therefore, in the substrate 140 in the present embodiment, a temperature sensor 143 is provided near the central portion of the light emitting elements 110 arranged linearly as shown in FIG. 4, so that the temperature near the light emitting elements can be detected.

The image forming apparatus of the present embodiment mainly includes a microprocessor (not shown) for executing the image forming process, and such microprocessor is detected by the temperature sensor 143 provided on the substrate 140. The temperature near the light emitting element 110 is detected by referring to the signal. Since the microprocessor also has a program for calculating the above equation (1), the amount of color misregistration is 1/2.
When it is detected that the number of pixels is exceeded, the above-described image forming process is stopped or the fan 300 corresponding to a cooling unit is driven to cool the substrate 140.

The linear thermal expansion coefficient α4 of the SLA 120 is determined by the FRP constituting it, and the value of the linear thermal expansion coefficient α4 at 20 ° C. is 10 × 10 ⁻⁶ ° C. ^−1.
As shown in FIG. 3, A120 projects from the holding member 130 in the radial direction of the image forming body by a length R4 (= 3 mm).

The holding member 130 is made of polycarbonate containing 30% of glass fiber having a linear thermal expansion coefficient α3 of 80 × 10 ^-6 ° C. ^-1 at 20 ° C., and the length R3 in the radial direction of the image forming body is set to 18 mm. Has been formed.

In the present embodiment, the light emitting element 1
Although 10 is described as an LED arrayed linearly, it is not limited to this, and a light emitting element such as FL (fluorescent substance emission), EL (electroluminescence), PL (plasma discharge) or the like can be linearly arranged. Line-shaped exposure elements, LISA (photomagnetic effect optical shutter array), PL
A similar effect can be obtained by arranging elements having an optical shutter function such as a ZT (transmissive piezoelectric element shutter array) and an LCS (liquid crystal shutter).

The optical support 200 comprises image exposure devices 11-1.
Two left and right optical support members 21 that support both ends of
1 and 212 are provided, and the shaft 213 is inserted into and supported by the central axis. Both ends of the image exposure devices 11 to 14 are attached and fixed to the outer peripheral surfaces of the optical support members 211 and 212. In the present embodiment, the optical support 20
0 is the coefficient of linear thermal expansion α1 at 20 ℃ is 24 × 10 ^-6 ℃
^-1 is used, and the shortest length R1 from the center of the image forming body to the holding surface for holding the holding member 130 is 12 m.
m.

In this embodiment, the image exposure devices 11 to 14 are used.
Support members 211 and 21 for supporting and attaching both ends of the
The second supporting portion has a regular hexagonal side surface, and is installed in advance so as to be flush with the surface plate or the like. However, this optical support member may be integrally molded, and the shape is not limited. Image exposure devices 11-14
Is adjusted in position, and then the length R in the radial direction of the image forming body is adjusted.
2 is 2 mm, the linear thermal expansion coefficient α2 at 20 ° C. is 70 ×
It is fixed with an adhesive through a wedge-shaped spacer 150 made of acrylic at 10 ^-6 ° C ^-1 .

The above is the image exposure apparatus 1 according to the present embodiment.
00 and the material of each member, and the relationship between these and the image shift of the image exposure apparatus 100 can be approximated by the following equation (2).

[0068]

(Equation 7)

Here, ΔT1 is the fluctuation range [K] near the light emitting element, R is the radius [μm] of the image forming body, and R is
1 is a spacer 1 from the center of the image forming body of the optical support 200.
The shortest distance [μm] to the holding surface to which 50 is bonded,
R2 is the length of the spacer 150 in the radial direction of the image forming body [μ
m], and R3 is a holding member 1 that holds the SLA 120.
30 in the radial direction of the image forming body [μm], R4
Is the radial length [μm] of the image forming body in which the SLA 120 protrudes from the holding member 130 in the image forming point direction, and α is the linear thermal expansion coefficient [° C.] of the material forming the translucent substrate of the image forming body.
⁻¹ ], α1 is the linear thermal expansion coefficient [° C. ⁻¹ ] of the material forming the optical support 200, α2 is the linear thermal expansion coefficient [° C. ⁻¹ ] of the material forming the spacer 150, α3 is the linear thermal expansion coefficient [° C. ⁻¹ ] of the material forming the holding member 130, and α4 is the linear thermal expansion coefficient [° C. ⁻¹ ] of the material forming the SLA 120.

Generally, when SLA is used for the imaging element,
Since the depth of focus of the SLA is ± 200 mm, it is necessary that the focus shift be 200 μm or less. Therefore, the above equation is

[0071]

(Equation 8)

By satisfying the condition, it is possible to provide an image forming apparatus capable of obtaining a focused and clear image.

In the present embodiment, the usable temperature is 0 ° C to
ΔT1 when the temperature is 60 ° C. and the temperature in the initial state is 20 ° C.
= 40 [K], and when ΔTl is calculated using the equation (2), ΔTl becomes about 130 μm. Therefore, if each member selected in this embodiment is used, the deviation of the image forming position is 2
The thickness is less than 00 μm, and a good image can be obtained.

The image forming apparatus according to the present embodiment mainly includes a microprocessor (not shown) for executing the image forming process, and such microprocessor is detected by the temperature sensor 143 provided on the substrate 140. The temperature near the light emitting element 110 is detected by referring to the signal. Since the microprocessor is also equipped with a program for calculating the above-mentioned formula (2), if it is detected that the imaging deviation Δl of the exposure apparatus 100 has changed by more than ± 200 μm, the above-mentioned image forming process is stopped. Alternatively, ΔT1 is controlled by driving the fan 300 corresponding to the temperature control means.

The chargers 21 to 24 perform a charging action on the photoconductor layer of the image forming body 1 by a control grid held at a predetermined potential and corona discharge by a discharge wire, and uniformly charge the image forming body 1. It is a scorotron charger that gives a high potential.

The developing units 31 to 34 contain one-component or two-component developers of yellow (Y), magenta (M), cyan (C) and black (K), respectively, and each of them surrounds the image forming body 1. A developing sleeve is provided which rotates in the same direction while maintaining a predetermined gap with respect to the surface. The developing devices 31 to 34 have a predetermined value, for example, 1 with the image forming body 1 by an abutting roller (not shown).
A non-contact state is maintained with a gap of 00 μm to 1000 μm, and during development by the developing devices 31 to 34 for each color, a developing bias in which a direct current or an alternating current is applied to the developing sleeve is applied to accommodate the developing device. Non-contact development with a one-component or two-component developer is performed, and a DC bias having the same polarity as that of the toner is applied to the image forming body 1 that grounds the transparent conductive layer, so that the toner does not adhere to the exposed portion. Contact reversal development is performed. Toners for replenishing each color are supplied from the toner replenishing tanks 81 to 84 with corresponding color developing devices 31 to 31.
34 is replenished.

[0077]

The inventions according to claims 1 to 3 are:
With the above configuration, it is possible to provide an image forming apparatus that retains the strength of the image forming body, suppresses heat generation from the exposure device, and is easy to assemble.

The inventions according to claims 4 to 6 can provide an image forming apparatus capable of forming a focused and clear image by including the above configuration.

The inventions according to claims 7 to 11 are:
With the above configuration, it is possible to provide an image forming apparatus capable of forming a color image while suppressing color misregistration.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to this embodiment.

FIG. 2 is a perspective view of the image exposure apparatus according to the present embodiment.

FIG. 3 is a cross-sectional view of essential parts of the image exposure apparatus.

FIG. 4 is a perspective view showing a substrate in which light emitting elements are linearly arranged.

[Explanation of symbols]

 1 Image Forming Body 11-14 Image Exposure Device 21-24 Charging Device 31-34 Developing Device 110 Light Emitting Element 120 Gradient Index Lens Array 130 Holding Member 140 Substrate 200 Optical Support

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G03G 15/01 112 H04N 1/036 (72) Inventor Hiroyuki Tokimatsu 2970, Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company (72) Inventor Masayasu Onodera 2970 Ishikawa-cho, Hachioji City, Tokyo Konica Stock Company (72) Inventor Toshihide Miura 5-14-14 Midoricho, Koganei-shi, Tokyo

Claims (11)

[Claims] 1. An exposure optical system in which an exposure light source in which light emitting elements are linearly arranged on a substrate and an image forming element for forming an image of a beam from the exposure light source on the surface of an image forming body and exposing the image are provided. In the image forming apparatus disposed inside the image forming body, the image forming body is formed to have a thickness of 1 to 8 mm, and the distance between the inner surface of the image forming body and the end surface of the imaging element is 0.5 to 10 mm. An image forming apparatus characterized in that there is. 2. A light emitting diode is used as the light emitting element,
The image forming apparatus according to claim 1, wherein a gradient index lens array is used as the image forming element. 3. The inner diameter φ of the image forming body is φ = 60 to 18
The image forming apparatus according to claim 1, wherein the image forming apparatus has a length of 0 mm. 4. An exposure optical system in which an exposure light source in which light-emitting elements are linearly arranged on a substrate and a gradient index lens array for image-exposing a beam from the exposure light source on the surface of an image forming body are arranged. An image forming apparatus having a system, which satisfies the following expression. [Equation 1] Here, ΔT1 is the fluctuation range [K] of the temperature near the light emitting element, R is the radius of the image forming body, and Ri is the radial direction of the image forming body of each member constituting the exposure optical system. The length is [μm], α is the linear thermal expansion coefficient [° C. ⁻¹ ] of the translucent substrate forming the image forming body, and αi is the linear thermal expansion coefficient of each member constituting the exposure optical system. [° C. ^-1 ]. 5. The equation 2 The image forming apparatus according to claim 4, wherein the image formation is stopped at the time of the above. 6. The equation 3 The image forming apparatus according to claim 4, further comprising a temperature control unit that controls ΔT1 so as to satisfy the above condition. 7. An exposure light source in which light emitting elements are linearly arranged on a substrate, an exposure optical system for forming a latent image on an image forming body with light from the exposure light source, and a plurality of sets of developing means are provided. An image forming apparatus for forming an image by superimposing a toner image on the image forming body by sequentially repeating the step of forming a toner image on the image forming body by the developing means after imagewise exposing the image forming body, An image forming apparatus satisfying the following formula. αA × L × ΔT2 ≦ ½ pixel diameter [μm] where αA is the linear thermal expansion coefficient [° C. ⁻¹ ] of the material used to form the substrate, and L is the image forming body axial direction of the substrate. Of the temperature [μm], and ΔT2 is 2 near the temperature of the light emitting element.
It is a temperature difference [0] from 0 ° C. 8. The substrate has a linear thermal expansion coefficient of 20 × 10 ^−6.
The image forming apparatus according to claim 7, wherein the image forming apparatus is formed of a material having a temperature of ^-1 or less. 9. The image forming apparatus according to claim 7, wherein the temperature in the vicinity of the light emitting element is used in the range of 0 to 60 ° C. 10. αA × L × ΔT2> 1/2 pixel diameter [μ
The image forming apparatus according to claim 7, wherein the image formation is stopped at the time of [m]. 11. αA × L × ΔT2 ≦ 1/2 pixel diameter [μ
8. The image forming apparatus according to claim 7, wherein the temperature control means for controlling ΔT2 is operated so as to satisfy m].