JP2000335003A - Image exposing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a color image free from color shift by constituting an image exposing device so that an LED substrate can be freely expanded and contracted without being affected by the intensity of holding force. SOLUTION: The upper cover DC for supporing a SELFOC lens 12b is brought into contact with the side wall 121d of the bottom cover 12d for supporting an LED substrate 123 to provide a gap with predetermined height between the undersurface of the upper cover 12c and the upper surface of the LED substrate 123 and an elastic member 126 is inserted in the gap under pressure to reduce the friction resistance applied to the LED substrate 123 to permit the LED substrate to freely expand and contract.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., which forms an image by arranging a charging means, a line recording means and a developing means around an image forming body. The present invention relates to an image exposure apparatus used in an image forming apparatus of a system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile or the like, an electrophotographic system in which a charging means, a linear recording means (image exposure means) and a developing means are arranged around an image forming body to form an image. Conventionally, as a method of forming a multi-color image, the same number of image forming bodies as necessary colors for image formation, charging means, developing means, etc., are formed on each image forming apparatus. A color image forming apparatus in which a single color toner image is superimposed on a recording material to form a color image, or an image forming body is rotated a plurality of times to charge by a charging unit for each color;
A color image forming apparatus that forms a color image by repeating image writing by a line recording unit (image exposing unit) and development by a developing unit, or charging by a charging unit for each color within one rotation of the image forming body, 2. Description of the Related Art There is known a color image forming apparatus and the like that sequentially forms an image by a shape recording unit (image exposing unit) and develops by a developing unit to form a color image.

However, each of the above-described image forming apparatuses is provided with the same number of image forming bodies, charging means, developing means, and the like as the number of colors required for image formation, and superposes a single color toner image formed on each image forming body on a recording material. A color image forming apparatus that forms a color image together has a drawback in that the volume of the apparatus is increased due to the need to convey a plurality of image forming bodies and recording materials. A color image forming apparatus that forms a color image by repeating charging, image writing and development has a reduced volume, but has a limitation that the size of the formed image is limited to the surface area of the image forming body or less. .

In this regard, a color image forming apparatus that forms a color image by sequentially performing charging, image writing, and development for each color within one rotation of the image forming body has no restriction on the size of the image and has a high speed image. There are advantages such as enabling formation. Further, a light-transmitting substrate is used as a substrate of an image forming body, and a line-shaped recording means for writing an image is arranged inside the image forming body to reduce the size of the apparatus. For example, Japanese Patent Application Laid-Open No. 5-307307 discloses the apparatus. Has been proposed by

[0005]

In the above-described color image forming apparatus for forming a color image by sequentially performing charging, image writing and development for each color within one rotation of the image forming body, high-speed image formation is possible. However, it is necessary to provide a plurality of sets of charging means, linear recording means (image exposing means), and developing means within one circumference of the photoreceptor. A function and performance capable of superimposing toner images of each color with high accuracy are required. In order to further reduce the size of the mounting, in order to accommodate a plurality of linear recording means for writing the image inside or outside the image forming body to make the image forming body small, a small linear recording means is required, A small exposure element (light emitting diode (hereinafter, LED) array module) is used for the line recording means. Therefore, as the LED array module (exposure element), a plurality of light emitting element chips (LED chips) in which a plurality of light emitting elements (LEDs) are linearly formed on a chip substrate are arranged in an array to form a light emitting element array (LED array). Those that have been used are particularly frequently used. The line-shaped recording means is composed of the LED array module and the gradient index lens array,
The LED array module and the IC driver for driving the LED array module are supported on an LED substrate, while the gradient index lens array is supported on an upper cover. As shown in FIG. The cover is pressed between the covers to form a unit as an image exposure apparatus.

However, in such an image exposure apparatus, the linear recording means expands and contracts due to thermal deformation due to heat generated from an IC driver serving as a heating element for driving an LED, and a positional shift occurs, thereby superimposing toner images of respective colors with high accuracy. The problem arises that they cannot be matched.

An object of the present invention is to solve the following problems.

The LED board expands and deforms due to the heat generated by the driving of the IC driver when the LED is turned on, and contracts by cooling when turned off to return to the original state. Since it is sandwiched, free expansion and contraction is hindered, and as a result, the amount of deformation varies, and the image exposure position, that is, the writing timing changes, which may cause color shift. SUMMARY OF THE INVENTION An object of the present invention is to provide an image exposure apparatus which is configured so that an LED substrate can freely expand and contract without being affected by the strength of a sandwiching force, thereby forming a color image without color shift.

As described above, the LED board tends to deform due to a temperature change when the LED is turned on and when the LED is turned off.
The upper cover and the bottom cover pressed against the LED board also tend to be deformed under the influence of the temperature change, so that the frictional force between the pressed faces prevents free expansion and contraction of the LED board, and as a result, the amount of deformation varies. The writing timing changes, which may cause color shift. SUMMARY OF THE INVENTION An object of the present invention is to provide an image exposure apparatus in which an LED substrate can be freely expanded and contracted without being affected by deformation of an upper cover and a bottom cover, thereby forming a color image without color shift. I do.

As described above, the LED substrate repeatedly expands and contracts by turning on and off the LEDs, but the expansion and contraction directions of the individual substrates do not always match, and as a result, several tens μm
m may occur and accumulate, and the writing timing in the main scanning direction may change to cause color shift. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image exposure apparatus that is configured to accurately return to an initial position even after an LED substrate repeatedly expands and contracts, thereby forming a color image without color shift.

As shown in FIG. 10, the position of the LED board is regulated by engaging the round hole and the long hole with the positioning pins provided on the upper cover or the bottom cover. Is inevitable, and as a result, several tens of microns
m, the writing timing in the sub-scanning direction changes, which may cause color shift. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image exposure apparatus that is configured such that an LED substrate is always secured at a predetermined set position, thereby forming a color image without color shift.

[0012]

The first object of the present invention is to form an exposure light source in which a plurality of light emitting diode elements are linearly arranged on a substrate, and connect the light from the exposure light source to an image forming body. In an image exposure apparatus, an upper cover member to which an exposure optical system provided with a gradient index lens array for image and image exposure is adhered and held by a bottom cover member insulated from the substrate. This is achieved by an image exposure apparatus (the invention according to claim 1), wherein an elastic member is attached between the substrate and the upper cover member.

The second object is to provide an exposure light source in which a plurality of light emitting diode element arrays are linearly arranged on a substrate.
An upper cover member to which an exposure optical system in which a refractive index distribution type lens array for forming light from the exposure light source on an image forming body and exposing the image is adhered, and a bottom cover insulated from the substrate; In the image exposure apparatus held between members, the amount of expansion and contraction of the entire length of the substrate and the upper cover member and the bottom cover member in the main scanning direction due to a temperature change when the image exposure apparatus is used, the upper cover member and An image exposure apparatus, wherein the materials of the substrate, the upper cover member, and the bottom cover member are defined so that the amount of change in the shape of the bottom cover member is equal to or less than the amount of change in the shape of the substrate. Invention according to item 6).

The third object is to provide an exposure light source in which a plurality of light emitting diode element arrays are linearly arranged on a substrate.
An upper cover member to which an exposure optical system in which a refractive index distribution type lens array for forming light from the exposure light source on an image forming body and exposing the image is adhered, and a bottom cover insulated from the substrate; In an image exposure apparatus held between members, the substrate is tensioned in the main scanning direction from an end portion, and is achieved by an image exposure apparatus (an invention according to claim 9).

The fourth object is to provide an exposure light source in which a plurality of light emitting diode element arrays are linearly arranged on a substrate.
An upper cover member to which an exposure optical system in which a refractive index distribution type lens array for forming light from the exposure light source on an image forming body and exposing the image is adhered, and a bottom cover insulated from the substrate; 14. An image exposure apparatus according to claim 13, further comprising means for pressing said substrate against a reference surface provided on said upper cover or said bottom cover. Invention).

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of each embodiment, an image forming process and each mechanism of an image forming apparatus having an image exposure apparatus according to the present invention will be described with reference to FIGS. 1 is a cross-sectional configuration diagram of a color image forming apparatus, FIG. 2 is a cross-sectional configuration diagram of a linear recording unit, and FIG. 3 is an explanatory diagram illustrating a method of attaching the linear recording unit to a support. FIG. 4 is a detailed view of an exposure element, and FIGS. 5 and 6 are cross-sectional configuration diagrams of an image forming body including a linear recording unit.

According to FIG. 1 or FIG. 2, a photosensitive drum 10 as a drum-shaped image forming member is, for example, a cylindrical light-transmitting resin base formed of a light-transmitting member made of a light-transmitting acrylic resin. Is provided inside, and a translucent conductive layer and an organic photoreceptor layer (OPC) are formed on the outer periphery of the substrate.
It is rotated in the direction shown by the arrow in FIG.

Reference numeral 11 denotes a scorotron charger as a charging means, which performs a charging action on the above-mentioned organic photoreceptor layer of the photoreceptor drum 10 by a grid maintained at a predetermined potential and corona discharge by a discharge electrode. 10 is given a uniform potential. As the discharge electrode, a wire electrode, a needle electrode, a saw-tooth electrode plate, or the like is used.

An exposure optical system 12 as a linear recording means for each of the colors Y, M, C and K has a plurality of LEDs (light emitting elements) arranged in a main scanning direction parallel to the axis of the photosensitive drum 10. An LED array module (also referred to as an exposure element) 12a, which is a linear light-emitting element array module in which light-emitting diodes (121a) are arranged in an array, and a gradient index lens array (trade name: Selfoc lens) as an imaging element 2b), the selfoc lens 12b is fixed to the upper cover 12c by, for example, an adhesive shown by a black circle in FIG. 2, and the exposure element 12a is exposed by, for example, an adhesive shown by a black circle. A state in which the exposure element 12a and the selfoc lens 12b are positioned and fixed to a metal bottom cover 12d as an element holding member. In, top to bottom cover 12d cover 1
2c are integrated by the clamping force of the clip 125.

As the light emitting element, FL (fluorescent light emission), EL (electroluminescence), PL (plasma discharge) and the like are used.

The exposure optical system 12 for each color is set in its set position in a state in which the main scanning direction with the photosensitive drum 10 and the sub-scanning direction of the rotating direction of the photosensitive drum 10 are previously determined by a jig or the like. The wedge surface is fitted to an auxiliary block 12f which is adjusted and held, and is attached to the center of a support member 20 using a pipe-shaped hollow member as a support of the line-shaped recording means, for example, with an adhesive indicated by a black circle. The spacer block 12e and the auxiliary block 12f are fixed to each other, and the metal casing 12d and the spacer block 12e are fixed to each other by, for example, an adhesive indicated by a black circle. The exposure optical system 12 is positioned by adjustment of the spacer block 12e whose wedge surface is aligned with the auxiliary block 12f, and is fixed at one point (see FIG. 5) at the center of the exposure optical system 12 to be fixed to the support member 20. While holding the exposure optical system 12 for each color, the center axis of the support member 20 is aligned with the center axis of the photoconductor drum 10 and arranged inside the photoconductor drum 10.
Therefore, an image is written on the photosensitive drum 10 by the exposure optical system 12 perpendicularly to the central axis of the photosensitive drum 10.

As the support member 20, which is a common support for each exposure optical system 12, a thin hollow member made of a light metal material such as aluminum or stainless steel, preferably a cylindrical pipe or square pipe is used. As a result, the weight and the heat capacity of the supporting member 20 using a metallic hollow member are reduced, the weight of the image forming unit is reduced, the heat capacity is small, the heat conductivity is good, and the temperature control is performed. The efficiency has been increased. In addition, cylindrical and prismatic pipes are also resistant to mechanical deformation.

The distance between the inner peripheral surface of the support member 20 and the outer peripheral surface of the substrate of the photoreceptor drum 10 is adjusted by the exposure optical system 1.
2, the bottom surface of the exposure optical system 12 has a circumferential surface which is always located outside the inner circumferential surface of the support member 20. The support member 20 does not need to break the cylindrical surface, the strength is maintained, and the exposure optical system 12 can be reliably held at a predetermined imaging position.

As described above, each of the exposure optical systems 12 is mounted on the support member 20 using a pipe-shaped hollow member and is housed inside the base of the photosensitive drum 10. Lead wires WA of the LED 121a are provided through connectors C which are pulled out from the element 12a and attached to both ends of a lower portion of the metal casing 12d (see FIG. 5).

A storage unit (not shown), such as an RA, which is read by an image scanner or input by an external signal or the like.
The image signal of each color stored in M is sequentially read from the storage unit through the control unit of the apparatus main body, and input as an electric signal to the exposure optical system 12 for each color, and the LED 121
a is emitted by, for example, a pulse width modulation method (PWM method). The emission wavelength of the light emitting element used in this embodiment is in the range of 600 to 900 nm.

According to FIG. 2, the exposure optical system 12 as a linear recording means for each of the colors Y, M, C and K includes a plurality of exposure optical systems arranged in a main scanning direction parallel to the axis of the photosensitive drum 10. LED array module (also referred to as exposure element) 12a which is a linear light emitting element array module in which LEDs (light emitting diodes) 121a as light emitting elements are arranged in an array.
And a light converging light transmitting body (also referred to as a trade name Selfoc lens) 12 as an imaging element made of a glass member 12
b, the selfoc lens 12b is fixed to a lens holder 12c made of a resin member by, for example, an adhesive, and further, the exposure element 12a and the selfoc lens 12b
In a state in which is positioned, the lens holder 12c is fixed to the metal casing 12d by the clip 125 to constitute the exposure optical system 12, but an LED array module (also referred to as an exposure element) as a light emitting element array module. As shown in FIG. 4, an LED chip 12a as a light-emitting diode element array formed by arranging a plurality of LEDs 121a as light-emitting elements on a chip substrate 121b in a linear manner is used as a substrate 12a.
An LED array as a light emitting element array is provided by arranging a plurality of LEDs on an ED substrate 123, and an IC driver 12 serving as a heating element is further disposed on the LED substrate 123.
4 mounted and an LED array module (exposure element) 1
2a is formed. That is, an LED made of a GaAs material
The chip 121 and the IC driver 124 are mounted on the LED board 123 as one substrate in a one-to-one correspondence with a bare chip. The degree of integration of the LED chip 121 is about 64 to 256 / chip, and
The element pitch 1a is uniquely determined by the image writing density of the color image forming apparatus. For example, to obtain a density of 400 DPI (dots / inch), the pitch is 63.5 μm.

The exposure element 12a of each of the above-mentioned exposure optical systems 12
The light emission is controlled by driving an IC driver included in each exposure optical system 12. IC driver 124
Is L, for example, as shown in FIG.
It is mounted on the ED substrate 123 or the like.

The exposure optical system 12 is supported by a single point support at the center as shown in FIG.
It is also possible to adopt a two-point support type at both ends as shown in FIG. 6. In this case, the exposure optical system 12 uses a square pipe or a cylindrical pipe support member 120 having a flat support portion.
The wedge-shaped spacer block 120A is inserted into the inclined surfaces at both ends and adjusted in position, and then fixed.

According to FIGS. 5 and 2, the exposure optical system 12 as a line recording means for each color is supported at one point by a spacer block 12e and an auxiliary block 12f, and is attached to a support member 20. However, the support member 20 supports the flange members 10A and 10B at the end of the photosensitive drum 10 via a bearing B1 held directly on the outer periphery and a bearing B2 held by a disk member 22 integrated with the support member 20, respectively. The photosensitive drum 10 is rotatably supported by the power of a driving gear G meshing with a gear 10G of the flange member 10A.

The support member 20 supports the photosensitive drum 10 and has a concave portion on both end surfaces, that is, an engaging portion 3 projecting from a convex portion provided on the side substrate 30 of the apparatus main body, that is, an inner surface.
1 and is fixed between the side substrates 30 by being inserted. When the support member 20 is held, the engagement pin 32 provided on the outer peripheral surface of the engagement portion 31 of the one side substrate 30 engages with the notch 20A on the end surface of the support member 20, and the fixing angle of the support member 20 is regulated. Each exposure optical system 12 is set at a predetermined position with respect to the apparatus main body, and a scorotron charger 1 as a charging unit disposed along the peripheral surface of the photosensitive drum 10.
The correct positional relationship is maintained with respect to the developing device 1 and the developing device 13 as the developing means.

The support member 20 is provided on the photosensitive drum 10.
The disk members 21 and 22 are coaxially and integrally provided on both outer sides of the photosensitive drum 10, and the disk member 22 is also used as a member for supporting one bearing B2 provided between the photosensitive member 10 and the photosensitive drum 10.

Each of the disk members 21 and 22 has an outer peripheral portion having a diameter substantially corresponding to the outer diameter of the photosensitive drum 10, and is provided on both ends of the developing sleeve 130 coaxially with the outer peripheral portion thereof. The position of the developing sleeve 130 is regulated by the abutting roller 130 </ b> A, and a predetermined developing gap is set between the peripheral surface of the developing sleeve 130 and the peripheral surface of the photosensitive drum 10.

Accordingly, since the photosensitive drum 10 is not subjected to a load due to the pressure contact of the developing device 13, the photosensitive drum 10 having no cylindrical shape does not cause distortion or deformation, and the toner image formed on the drum surface is superposed. There is no displacement or the like due to deformation or the like between them. Further, since the vibration of the developing unit 13 is not directly transmitted to the photosensitive drum 10, there is no occurrence of blurring during image exposure. Thus, the photosensitive drum 10
Is always driven and rotated while maintaining high precision roundness, and as a result, high quality color image formation is realized.

In general, the photoconductor drum 10 is limited by the scale of the apparatus and the plural scorotron chargers 11, plural developing devices 13 and the cleaning device 100 (see FIG. 1) installed on the outer peripheral surface of the photoconductor drum 10. Accordingly, a drum having an outer diameter between 50 mm and 200 mm is preferably used. In this case, in order to maintain rigidity, the thickness of the substrate of the photosensitive drum 10 is 2 mm corresponding to the drum diameter.
To 10 mm, while these photosensitive drums 10
The above-mentioned supporting member 20 for supporting the
2 and its imaging distance, the diameter becomes smaller, and in the case of a cylindrical pipe, the outer diameter is set to 20 mm to 160 mm, and the thickness of the support member 20 is set to 0.5 mm to 5 mm corresponding to the outer diameter. In addition, it is possible to set each exposure optical diameter 12 on the support member 20 with a margin.

The wiring section of each exposure optical system 12, that is, the connector C of each exposure optical system 12 connected to the power supply of the apparatus main body is provided at both ends at the same position on the bottom surface, while the support member 20 is provided at both ends. An insertion hole 20H is opened at a peripheral surface position facing each connector C, and each connector C is accommodated in the space of each insertion hole 20H when each exposure optical system 12 is attached and fixed to the support member 20.

After the connection between the connector C and the power supply, each of the insertion holes 20H is closed together with the lead wire WA with the seal member S from the inner peripheral side of the support member 20, so that scattered toner and dust etc. Intrusion is prevented.

As the sealing material S, for example, a curable silicone rubber sheet is used, and each of the insertion holes 20H is closed by an adhesive or the like, whereby airtightness is maintained. Further, an adhesive or an elastic member such as urethane foam or a rubber material is filled in the insertion hole 20H to prevent intrusion of toner or dust.

As a result, the lead wire WA extends along the inner peripheral surface of the support member 20 without being strongly bent, and furthermore, the insertion hole 30H is provided in the engaging portion 31 of the side substrate 30, so that the power supply on the apparatus body side can be easily provided. It will be connected. Accordingly, the holding member of the exposure element does not receive stress from the lead wire WA and does not come off due to bending of the lead wire.

Reference numerals 13Y to 13K denote developing units as developing means for accommodating yellow (Y), magenta (M), cyan (C), and black (K) developers, respectively. On the other hand, there is provided a developing sleeve 130 that rotates in the same direction while maintaining a predetermined gap.

Each of the above-mentioned developing units makes the electrostatic latent image on the photosensitive drum 10 formed by the above-described charging by the scorotron charger 11 and image exposure by the exposure optical system 12 contactless by applying a developing bias voltage. Develop reversely in the state of.

The original image is temporarily stored in an image reading apparatus separate from the present apparatus in the form of an image read by an image sensor or an image edited by a computer as an image signal for each color of Y, M, C and K. And stored.

At the start of image recording, the photosensitive drum 10 is rotated counterclockwise by the start of the photosensitive member drive motor, and at the same time, the application of potential to the photosensitive drum 10 is started by the charging action of the scorotron charger 11 (Y). Is done.

After the photosensitive drum 10 is applied with a potential, the exposure optical system 12 (Y) starts exposure with an electric signal corresponding to a first color signal, that is, an image signal of yellow (Y). An electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface by the rotational scanning.

The latent image of yellow (Y) is developed by a developing unit 13 (Y).
As a result, the developer on the developing sleeve is reversely developed in a non-contact state, and a yellow (Y) toner image is formed according to the rotation of the photosensitive drum 10.

Next, the photosensitive drum 10 is yellow (Y).
A potential is further applied to the toner image by the charging action of the scorotron charger 11 (M), and the exposure optical system 12 (M)
Is exposed by an electric signal corresponding to the second color signal, i.e., the magenta (M) image signal, and the non-contact reversal development by the developing unit 13 (M) is performed on the yellow (Y) toner image. The magenta (M) toner images are sequentially superimposed and formed.

The scorotron charger 11 (C), the exposure optical system 12 (C) and the developing device 13
(C) further forms a cyan (C) toner image corresponding to the third color signal, and the scorotron charger 11
(K), a black (K) toner image corresponding to the fourth color signal is sequentially superimposed by the exposure optical system 12 (K) and the developing device 13 (K), and is formed within one rotation of the photosensitive drum 10. Then, a color toner image is formed on the peripheral surface.

The exposure of the organic photosensitive layer of the photosensitive drum 10 by each of the exposure optical systems 12 is performed by the photosensitive drum 10.
From the inside through a substrate that is transparent to the above-mentioned exposure wavelength. Therefore, the exposure of the images corresponding to the second, third, and fourth color signals is performed without any influence from the previously formed toner image, and is equivalent to the image corresponding to the first color signal. It is possible to form an electrostatic latent image. In the developing operation of each developing device 13, a developing bias in which a direct current or a further alternating current is applied to the developing sleeve 130 is applied, and jumping development is performed by a one-component or two-component developer contained in the developing device 13. ,
Non-contact reversal development is performed on the photosensitive drum 10 that grounds the translucent conductive layer.

The color toner images of four colors of Y, M, C and K formed on the peripheral surface of the photosensitive drum 10 are transferred onto the peripheral surface of the intermediate transfer belt 14 provided as an intermediate transfer member. .

The intermediate transfer belt 14, which is an intermediate transfer member, has a volume resistivity of 10 ⁸ to 10 ¹⁶ Ω · cm, preferably 10 ⁹ to 10 ¹⁶ Ω · cm.
An endless belt of 10 ¹² Ω · cm, for example, a conductive material dispersed in engineering plastics such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, nylon alloy, and the like. It is a seamless belt having a two-layer structure in which a 0.05 mm semiconductive film substrate is coated with a fluorine coating having a thickness of 5 to 50 μm, preferably as a toner filming preventing layer. In addition, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicon rubber, urethane rubber, or the like can be used as the base of the belt. The intermediate transfer belt 14 is stretched between a guide roller 14A, a transfer roller 14B serving as a transfer unit, an entrance roller 14C, and a backup roller 14D, and is synchronized with the peripheral speed of the photosensitive drum 10 by power transmitted to the backup roller 14D. The paper is circulated clockwise as indicated by the arrow in FIG.

The intermediate transfer belt 14 forms a transfer area (primary transfer area) of the toner image on the belt surface by bringing the belt surface between the guide roller 14A and the transfer roller 14B into contact with the peripheral surface of the photosensitive drum 10; On the other hand, the belt surface on the outer periphery of the entrance roller 14C is in contact with a roller transfer unit 15 which is a transfer member, and a transfer area (secondary transfer area) of the toner image to the recording material is formed at the contact point.

The color toner image adhered to the peripheral surface of the photosensitive drum 10 is first applied to the intermediate transfer belt 14 by applying a bias voltage having the opposite polarity to the toner to the transfer roller 14B at the contact point between the intermediate transfer belt 14 and the intermediate transfer belt. 14 is transferred to the peripheral surface side. That is, the color toner image on the photosensitive drum 10 is transported to the transfer area without scattering the toner by the guide of the grounded guide roller 14A.
By applying a bias voltage of 1 to 3 kV to B, the image is efficiently transferred to the intermediate transfer belt 14 side (primary transfer).

On the other hand, the recording paper P as a recording material is carried out from a paper supply cassette (not shown) by the operation of the paper supply roller 17 and fed to the timing roller 18, and the color toner image on the intermediate transfer belt 14 is transferred. The sheet is fed to a transfer area (secondary transfer area) of the roller transfer unit 15 which is a transfer member in synchronization with the conveyance of the sheet.

The roller transfer unit 15 is rotated in a counterclockwise direction in synchronization with the peripheral speed of the intermediate transfer belt 14, and the fed recording paper P is moved from the entrance roller 14C which is in a ground contact state with the roller transfer unit 15. In the secondary transfer area formed by the nip portion between the toner images, the color toner image is brought into close contact with the color toner image on the intermediate transfer belt 14 and a bias voltage having a polarity opposite to that of the toner of 1 to 2 kV is applied to the roller transfer unit 15 to form the color toner image on the recording paper. It is transferred onto P (secondary transfer).

The recording paper P to which the color toner image has been transferred is neutralized by the brush neutralizer 15A, transported to the fixing device 91 via the transport plate 19, and sandwiched and transported between the heat roller 91A and the pressure roller 91B. Then, after the toner is fused and fixed, the toner is discharged to the outside of the apparatus via a discharge roller 92.

Cleaning devices 100 and 140 as cleaning means are installed on the photosensitive drum 10 and the intermediate transfer belt 14, respectively, and the blades of the respective devices are constantly pressed against each other to remove the remaining adhered toner. The surrounding surface is always kept clean.

(Embodiment 1) An embodiment according to the first aspect of the present invention will be described with reference to FIGS.

Each exposure optical system 12 included in the image exposure apparatus of the present invention is
And a side wall 121d of the bottom cover 12d abuts and is integrated, and a gap is provided between the lower surface of the upper cover 12c and the LED board 123, and the gap is pressed. The elastic member 126 is inserted in a crimped state.

Exposure optical system 1 of selfoc lens 12b
The optical positional relationship with respect to 2a is such that the optical axis direction is the upper cover 1
By the contact of the bottom cover 2c with the bottom cover 2c, the three positioning pins 12p provided in the top cover 12c in the plane direction are moved as shown in FIG.
The round hole H1 of the LED board 123 and the bottom cover 12d shown in FIG.
And the long hole H2 respectively.

As the elastic member 126, an elastic member having a moderate elasticity and a small static friction coefficient is suitable, and is made of, for example, a sponge or a soft rubber as shown in FIGS. 7 (a) and 7 (b). The elastic member 126A or a leaf spring type elastic member 1 as shown in FIG.
26B is used.

The LED board 123 is indirectly fixed to the upper cover 12c through the pins 12p as shown in FIG. 7 only at the central portion in the longitudinal direction, that is, in the vicinity of the round hole H1, with an adhesive shown by a black circle.

Accordingly, each LED board 123 is
Since the frictional resistance of the upper cover 12c is reduced by the low frictional resistance of 26 and its easy elastic deformation, and the support for the bottom cover 12d is only one place, the expansion and contraction at the time of heating and cooling is free. As a result, there is no variation in the exposure position between the exposure optical systems 12, and the color shift of the image is eliminated.

(Embodiment 2) The invention according to claim 6 will be described with reference to FIGS.

Each exposure optical system 1 provided in the image exposure apparatus of the present invention.
2, a glass material (linear expansion coefficient at 20 ° C. 3 × 10 ⁻⁶ / ° C.) is used as a material of the LED substrate 123, and each material of the upper cover 12 c and the bottom cover 12 d has a lower linear expansion number than the above glass material. A small ceramic (linear expansion coefficient at 20 ° C. 2 × 10 ⁻⁶ / ° C.) and an invar alloy (linear expansion coefficient at 20 ° C. 1-2 × 10 ⁻⁶ / ° C.) are used.

The LED board 123 is provided on the upper cover 12c.
The three positioning pins 12p of the LED board 123
The bottom cover 12d is fixed to the bottom cover 12d with an adhesive indicated by a black circle only in the vicinity of the round hole H1 located at the center in the longitudinal direction while being engaged with the round hole H1 and the long hole H2 of the bottom cover 12d. .

Therefore, the LED substrate 123 receives stress due to expansion and contraction of the upper cover 12c and the bottom cover 12d during expansion and contraction during heating and cooling. However, due to the above-described difference in linear expansion coefficient, the LED substrate 123 is moved between the upper cover 12c and the bottom cover 12d.
As a result, the LED substrate 123 of each of the exposure optical systems 12 receives a force in a direction in which expansion and contraction is hindered.

(Embodiment 3) The invention according to claim 9 will be described with reference to FIGS.

In each of the exposure optical systems 12 provided in the image exposure apparatus of the present invention, the LED substrate 123 is slidably engaged between both side walls 121d of the bottom cover 12d, and one end has only a round hole H1. The positioning pin 12p of the upper cover 12c is engaged with the round hole H1 and is fixed by bonding, and is regulated by the side wall 121d in the width direction and by the positioning pin 12p in the longitudinal direction. A planar positional relationship with the selfoc lens 12b is set.

The LED board 123 further has a tension spring SP1 mounted between the other end opposite to the round hole H1 and the bottom cover 12d, and is always in the longitudinal direction based on the positioning pin 12p. A tensile force is being applied. Since the tension spring SP1 allows the LED board 123 to freely expand and contract, the spring constant is set so that a tensile force acting on the LED board 123 is at least 500 g and does not exceed 3000 g at most.

The LED substrate 123 expands in response to a rise in temperature by overcoming the frictional resistance between the LED cover 123 and the bottom cover 12d by the tensile force of the tension spring SP1 during heating accompanying driving of the IC driver 124. At the time of cooling, it contracts in response to the falling temperature mainly against the tensile force of the tension spring SP1.

Therefore, the LED substrate 12 of each exposure optical system 12
No. 3 expands and contracts by an equal amount in a uniform direction in accordance with a change in temperature. As a result, variations in the exposure position are eliminated, and the color shift of the image is eliminated.

The LED board 123 is shown in FIG.
As shown in the above, it is also possible to reduce the amount of expansion and contraction corresponding to the temperature change to half by providing the round hole H1 at the center in the longitudinal direction and applying the tensile force of the tension spring SP2 to both ends.

(Embodiment 4) The invention according to claim 13 will be described with reference to FIGS.

In each of the exposure optical systems 12 provided in the image exposure apparatus of the present invention, a predetermined gap is provided between one side end face of the LED board 123 and the inner side face of the one side wall 121d of the bottom cover 12d opposed thereto. The plurality of elastic members 127 are inserted into the gap in a state of being pressed.

As the elastic member 127, an elastic member having an appropriate elasticity and a small static friction coefficient is suitable. For example, an elastic member 127A made of a sponge or a soft rubber as shown in FIG. A leaf spring type pressing member 127B as shown in FIG.

The LED substrate 123 is brought into contact with the inner surface of the side wall 121d of the bottom cover 12d provided with the other side end surface as a reference surface facing the LED substrate 123 by the elastic action of the elastic member 127, and furthermore, the center in the longitudinal direction. Since only one long hole H2 is provided in the portion and the positioning pin 12p of the upper cover 12c is engaged with the long hole H2, the position in the planar direction with respect to the selfoc lens 12b is regulated.

The above-mentioned LED board 123 is used when the temperature rises due to the driving of the IC driver 124 and when the cooling is stopped.
The width direction always expands and contracts with a fixed directionality with respect to the side end face contacting the side wall 121d of the bottom cover 12d, and the longitudinal direction with a certain directionality with respect to the positioning pin 12p.

Therefore, the LED substrate 12 of each exposure optical system 12
No. 3 expands and contracts in a uniform direction in response to a change in temperature. As a result, variations in the exposure position are eliminated, and the color shift of the image is eliminated.

Each of the elastic members 127 is fixed and supported on the inner surface of the inserted side wall 121d with an adhesive indicated by a black circle.

[0079]

According to the image exposure apparatus of the present invention, the LED substrate forming the exposure light source can reduce the pressing load received from its support member and the support member of the optical system (claims 1 to 5). The stress caused by the difference in expansion and contraction caused by the temperature change from each support member is also reduced (claims 6 to 8), and free expansion and contraction is promoted (claims 9 to 12). Items 13 to 1
6) Therefore, each of the exposure optical systems is set to a common image writing position corresponding to the environmental temperature, and as a result, an image exposure apparatus capable of effectively eliminating a color shift due to a temperature change is provided. It was decided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus including an image exposure apparatus of the present invention.

FIG. 2 is a cross-sectional configuration diagram of a linear recording unit.

FIG. 3 is an explanatory view showing a method of attaching a linear recording means to a support.

FIG. 4 is a detailed view of an LED substrate.

FIG. 5 is a sectional configuration diagram of an image forming body (part 1) including an image exposure apparatus.

FIG. 6 is a cross-sectional configuration diagram of an image forming body (part 2) including an image exposure apparatus.

FIG. 7 is a cross-sectional configuration diagram of an image exposure apparatus that presses an LED substrate with an elastic member.

FIG. 8 is a cross-sectional configuration diagram of an image exposure apparatus that urges an LED substrate by an elastic member.

FIG. 9 is a cross-sectional configuration diagram of an image exposure apparatus that urges an LED substrate in a certain direction by pressing means.

FIG. 10 is a configuration example of a conventional image exposure apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photoconductor drum 12 Exposure optical system 12a LED array module 12b Selfoc lens 12c Top cover 12d Bottom cover 20 Support member 121 LED chip 123 LED board 124 IC driver 125 Clip 126,127 Elastic member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masayasu Onodera 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Co., Ltd. (72) Inventor Toshihide Miura 5-14-14 Midoricho, Koganei-shi, Tokyo F term (reference) 2C162 AE21 AE28 AE69 FA17 FA45 FA50 FA63 FA70 2H030 BB02 BB42 2H076 AB42 AB51 AB63

Claims (16)

[Claims] 1. A refractive index distribution type lens array for forming an exposure light source having a plurality of light-emitting diode elements linearly arranged on a substrate, forming an image of light from the exposure light source on an image forming body and exposing the image. An upper cover member to which the exposure optical system provided is bonded,
An image exposure apparatus wherein the substrate is held between an insulated bottom cover member and an elastic member is mounted between the substrate and the upper cover member. 2. The image exposure apparatus according to claim 1, wherein the substrate is bonded to the upper cover member or the bottom cover member at at least one position. 3. The urethane foam, which generates a pressing force by compression, is used as the elastic member.
Or the image exposure apparatus according to 2. 4. The rubber member which generates a pressing force by compression as said elastic member.
3. The image exposure apparatus according to claim 1. 5. The image exposure apparatus according to claim 1, wherein a leaf spring that generates a pressing force by compression is used as the elastic member. 6. A gradient-index lens for exposing an exposure light source having a plurality of light-emitting diode element arrays linearly arranged on a substrate to form an image by exposing light from the exposure light source onto an image forming body. An upper cover member to which an exposure optical system in which an array is provided is adhered, and an image exposure apparatus held and held by a bottom cover member insulated from the substrate, wherein the temperature change due to a temperature change when the image exposure apparatus is used. Regarding the amount of expansion and contraction of the entire length of the substrate and the upper cover member and the bottom cover member in the main scanning direction, such that the amount of change in the shape of the upper cover member and the bottom cover member is equal to or less than the amount of change in the shape of the substrate. An image exposure apparatus, wherein materials of the substrate, the upper cover member, and the bottom cover member are defined. 7. The substrate and the upper cover member such that a linear expansion coefficient of a material of the upper cover member and the bottom cover member at a temperature at which the image exposure apparatus is used is equal to or less than a linear expansion coefficient of a material of the substrate. The image exposure apparatus according to claim 6, wherein materials of the cover member and the bottom cover member are defined. 8. The image exposure apparatus according to claim 6, wherein the substrate is bonded to the upper cover member or the bottom cover member at at least one position. 9. A gradient index lens for exposing an exposure light source having a plurality of light emitting diode element arrays linearly arranged on a substrate to light from the exposure light source on an image forming body to perform image exposure. In an image exposure apparatus held between an upper cover member to which an exposure optical system provided with an array is adhered and a bottom cover member that is insulated from the substrate, the substrate is tensioned from an end in a main scanning direction. An image exposure apparatus, characterized in that the image exposure apparatus is subjected to the following. 10. The image exposure apparatus according to claim 9, wherein the substrate is bonded to the upper cover member or the bottom cover member at at least one position. 11. The image exposure apparatus according to claim 9, wherein the tension is obtained by using a tension spring. 12. The image exposure apparatus according to claim 9, wherein the tension is from 500 to 3000 g. 13. A refractive index distribution type lens for forming an exposure light source having a plurality of light emitting diode element arrays linearly arranged on a substrate, forming an image of the light from the exposure light source on an image forming body and exposing the image. In an image exposure apparatus in which an upper cover member to which an exposure optical system in which an array is provided is bonded and a bottom cover member that is insulated from the substrate are held, the substrate is placed on the upper cover or the bottom cover. An image exposure apparatus, comprising: means for pressing a reference surface provided. 14. An image exposure apparatus according to claim 13, wherein a leaf spring which generates a pressing force by compression is used as said pressing means. 15. An image exposure apparatus according to claim 13, wherein urethane foam which generates a pressing force by compression is used as said pressing means. 16. An image exposure apparatus according to claim 13, wherein said pressing means uses rubber that generates a pressing force by compression.