JP2010042633A - Line head, lens array for line head, and method for producing its mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: when a mold is produced by machining such as cutting, it takes long time and uniform working is difficult for a tool is consumed; and, although the tool can be replaced during the working, the accuracy of a lens position is difficult to secure because a lens surface position is changed due to the dislocation of a tool position between before and after the replacement. <P>SOLUTION: A method for producing the mold of a lens array, in which a plurality of concave surfaces forming a lens are arranged in the first direction XX, includes: a process for forming the first original board 310 with a plurality of the concave surfaces corresponding to the concave surfaces formed in the first direction XX by machining; a process for forming the second original boards 320a, 320b, and 320c with a plurality of convex surfaces formed by injection molding from the first original board 310; a process for forming the third original board 330 by arranging a plurality of the second original boards 320a, 320b, and 320c in the first direction XX; and a process for forming the mold by electroforming from the third original board 330. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a line head that scans light on a surface to be scanned of a latent image carrier, a lens array used therefor, and a method for manufacturing the mold.

A line head that forms a latent image by scanning light on a surface to be scanned of a photosensitive member that is a latent image carrier is used as a light source of an electrophotographic printer that is an image forming apparatus.
An optical printer head as a line head includes a head substrate on which a plurality of light emitting element groups are mounted, and a lens array having lenses corresponding to the light emitting element groups.

As a method of manufacturing an LED array that is a line head, a micro lens array that is a line head lens array, and a mold thereof, a method of forming a resin lens on a glass lens substrate is known (see, for example, Patent Document 1). In this method, a mold is formed by photolithography and electroforming, and a lens is formed on a glass substrate using a photocurable resin.
As a microlens array and a manufacturing method thereof, a method is known in which a resin film on which microlenses are formed is bonded to a substrate portion made of glass or a translucent resin (see, for example, Patent Document 2). In this method, a mold is formed by electroforming from an existing mold processed by cutting, and a lens is formed on a glass substrate using a photocurable resin.

Japanese Patent Laying-Open No. 2005-276849 (pages 7 and 8, FIGS. 9 to 13) JP 2002-122706 A (page 6, FIG. 6 and FIG. 7)

The lens diameter of the lens formed in the lens array is about 1 mm, and the lens height is about 0.3 mm. When a mold corresponding to a lens array is manufactured by photolithography, the corresponding lens height is about 0.1 mm, and when a lens surface higher than this is formed, unevenness of etching becomes noticeable and required. It is difficult to achieve surface shape accuracy and surface roughness.
When a mold is manufactured by machining such as cutting, time is required for processing, tools are consumed, and uniform processing is difficult. In addition, it is possible to change the tool in the middle, but the position of the tool shifts before and after the change, so that the lens surface position changes, and it is difficult to ensure the positional accuracy of the lens.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A process of forming a first master having a concave surface in a first direction by machining, and a resin master having a convex surface formed by injection molding from the first master Forming a second master by cutting an end of the resin master in the first direction, and arranging the second master in the first direction to form a third master A method of manufacturing a lens array mold, comprising: forming a master disk; and forming a mold from the third master disk by electroforming.

  According to this application example, the resin master is formed from the first master by injection molding, and a resin master having the same surface shape accuracy and surface roughness as the first master is obtained. The 2nd original disk which cut off the edge part in the 1st direction of the resin original disk is provided with the same surface shape accuracy and surface roughness as the 1st original disk. The third master is formed by arranging a plurality of second masters in the first direction, and a third master having the same surface shape accuracy and surface roughness as the second master is obtained. The mold for forming the lens array is obtained as an integral mold that is long in the first direction by electroforming from the third master, and the surface shape accuracy and surface roughness of the second master are transferred. Therefore, a lens array mold manufacturing method is obtained in which the surface shape accuracy and surface roughness of the mold obtained by electroforming from the third master are equivalent to those of the first master and integrated.

  Further, since the first master is shorter than the length in the first direction, the master that forms the first master can be shortened, and the time required for machining can be shortened. In addition, the number of exchanges of tools and the like is reduced by machining. Therefore, a method of manufacturing a lens array mold in which the positional accuracy of the lens is ensured can be obtained.

  Application Example 2 The second master is provided with an alignment mark, and the step of forming the third master is configured such that a gap is formed between the second master and the second master according to the alignment mark. A method for manufacturing a lens array mold as described above, wherein the mold is provided.

  In this application example, since the second masters are arranged according to the alignment marks, it is easy to align the convex surfaces of the respective second masters. Further, by providing a gap between the second masters, play occurs at the time of alignment, and alignment is easier to perform. Therefore, a method of manufacturing a lens array mold in which the positional accuracy of the lens is ensured can be obtained.

Application Example 3 The method for manufacturing a lens array mold according to the above, wherein the gap is filled with resin.
In this application example, the second master is integrally formed by filling the gap between the second masters with resin.

Application Example 4 The method for manufacturing a lens array mold described above, wherein the concave surface of the first master is two-dimensionally arranged.
In this application example, a method of manufacturing a lens array mold including a plurality of rows of lenses in the first direction is obtained.

Application Example 5 A lens array formed by using the lens array mold manufactured by the lens array mold manufacturing method described above.
According to this application example, a lens array that can achieve the above-described effects can be obtained.

Application Example 6 A line head comprising: the lens array described above; and a head substrate provided with two or more light emitting elements that emit light formed by the lenses of the lens array. .
According to this application example, a line head that can achieve the above-described effects can be obtained.

Hereinafter, embodiments will be described with reference to the drawings.
(Embodiment)

  FIG. 1 is a diagram illustrating an embodiment of an image forming apparatus 1. FIG. 2 is a diagram showing an electrical configuration of the image forming apparatus 1 of FIG. This apparatus uses only a black (K) toner, a color mode for forming a color image by superposing four color toners of black (K), cyan (C), magenta (M), and yellow (Y). Thus, the image forming apparatus can selectively execute a monochrome mode for forming a monochrome image. In this image forming apparatus 1, when an image forming command is given from an external device such as a host computer to a main controller MC having a CPU, a memory, etc., the main controller MC gives a control signal to the engine controller EC and an image forming command. Is provided to the head controller HC. The head controller HC controls the line head 29 for each color based on the video data VD from the main controller MC, the vertical synchronization signal Vsync from the engine controller EC, and parameter values. As a result, the engine unit EG executes a predetermined image forming operation, and forms an image corresponding to the image forming command on a sheet such as a copy sheet, a transfer sheet, a sheet, and an OHP transparent sheet.

  In the housing main body 3 of the image forming apparatus 1 according to the present embodiment, an electrical component box 5 containing a power circuit board, a main controller MC, an engine controller EC, and a head controller HC is provided. An image forming unit 7, a transfer belt unit 8, and a paper feeding unit 11 are also disposed in the housing body 3. In FIG. 1, a secondary transfer unit 12, a fixing unit 13, and a sheet guide member 15 are disposed on the right side in the housing body 3. The paper feeding unit 11 is configured to be detachable from the housing body 3. The paper feed unit 11 and the transfer belt unit 8 can be removed and repaired or exchanged.

  The image forming unit 7 includes four image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form a plurality of different color images. Each of the image forming stations Y, M, C, and K is provided with a photosensitive drum 21 on which a toner image of each color is formed. Each photosensitive drum 21 is connected to a dedicated drive motor and is driven to rotate at a predetermined speed in the direction of rotation D21. As a result, the surface of the photosensitive drum 21 is conveyed in the sub-scanning direction. A charging unit 23, a line head 29, a developing unit 25, and a photoconductor cleaner 27 are disposed around the photoconductive drum 21 along the rotation direction. Then, a charging operation, a latent image forming operation, and a toner developing operation are executed by these functional units. Therefore, when the color mode is executed, the toner images formed at all the image forming stations Y, M, C, and K are superimposed on the transfer belt 81 of the transfer belt unit 8 to form a color image, and the monochrome mode is executed. In some cases, a monochrome image is formed using only the toner image formed at the image forming station K. In FIG. 1, the image forming stations of the image forming unit 7 have the same configuration, and therefore, for convenience of illustration, only some image forming stations are denoted by reference numerals, and the other image forming stations are omitted. .

  The charging unit 23 includes a charging roller whose surface is made of elastic rubber. The charging roller is configured to rotate in contact with the surface of the photosensitive drum 21 at the charging position, and at a peripheral speed in the driven direction with respect to the photosensitive drum 21 as the photosensitive drum 21 rotates. Followed rotation. The charging roller is connected to a charging bias generator (not shown). The charging roller is supplied with the charging bias from the charging bias generator and is charged at the charging position where the charging unit 23 and the photosensitive drum 21 come into contact with each other. The surface of 21 is charged.

  The line head 29 includes a plurality of light emitting elements arranged in the axial direction of the photosensitive drum 21 (direction perpendicular to the paper surface of FIG. 1), and is spaced apart from the photosensitive drum 21. From these light emitting elements, the surface of the photosensitive drum 21 charged by the charging unit 23 is irradiated with light to form a latent image on the surface. In the present embodiment, a head controller HC is provided to control the line heads 29 for each color, and controls each line head 29 based on video data VD from the main controller MC and signals from the engine controller EC. ing. That is, in the present embodiment, image data included in the image formation command is input to the image processing unit 51 of the main controller MC. Various image processing is performed on the image data to create video data VD for each color, and the video data VD is given to the head controller HC via the main-side communication module 52. In the head controller HC, the video data VD is given to the head control module 54 via the head side communication module 53. As described above, the head controller module 54 is supplied with the signal indicating the parameter value related to the latent image formation and the vertical synchronization signal Vsync from the engine controller EC. Based on these signals, video data VD, and the like, the head controller HC creates a signal for controlling element driving for the line head 29 of each color, and outputs the signal to each line head 29. Thus, the operation of the light emitting elements is appropriately controlled in each line head 29, and a latent image corresponding to the image formation command is formed.

  In this embodiment, the photosensitive drum 21, the charging unit 23, the developing unit 25, and the photosensitive cleaner 27 of each of the image forming stations Y, M, C, and K are unitized as a photosensitive cartridge. Each photoconductor cartridge is provided with a nonvolatile memory for storing information related to the photoconductor cartridge. Then, wireless communication is performed between the engine controller EC and each photoconductor cartridge. In this way, information on each photoconductor cartridge is transmitted to the engine controller EC, and information in each memory is updated and stored.

  The developing unit 25 has a developing roller 251 on which toner is carried. The charged toner is developed at a developing position where the developing roller 251 and the photosensitive drum 21 come into contact with each other by a developing bias applied to the developing roller 251 from a developing bias generator (not shown) electrically connected to the developing roller 251. Is moved from the developing roller 251 to the photosensitive drum 21, and the electrostatic latent image formed by the line head 29 becomes obvious.

  The toner image that has been made visible at the development position in this way is conveyed in the rotational direction D21 of the photosensitive drum 21, and then the primary transfer position TR1 where the transfer belt 81, which will be described in detail later, and each photosensitive drum 21 come into contact with each other. 1 is primarily transferred to the transfer belt 81.

  In the present embodiment, a photoreceptor cleaner 27 is provided in contact with the surface of the photoreceptor drum 21 on the downstream side of the primary transfer position TR1 in the rotation direction D21 of the photoreceptor drum 21 and on the upstream side of the charging unit 23. It has been. The photoconductor cleaner 27 is in contact with the surface of the photoconductor drum 21 to remove the toner remaining on the surface of the photoconductor drum 21 after the primary transfer.

  The transfer belt unit 8 is driven to circulate in the direction of the arrow D81 (conveying direction) stretched around the driving roller 82, a driven roller 83 (blade facing roller) disposed on the left side of the driving roller 82, and these rollers. The transfer belt 81 is provided. Further, the transfer belt unit 8 is disposed on the inner side of the transfer belt 81 so as to be opposed to each of the photosensitive drums 21 included in the image forming stations Y, M, C, and K when the photosensitive cartridge is mounted. Four primary transfer rollers 85Y, 85M, 85C, and 85K are provided. Each of these primary transfer rollers 85 is electrically connected to a primary transfer bias generator (not shown). As will be described in detail later, when the color mode is executed, as shown in FIG. 1, all the primary transfer rollers 85Y, 85M, 85C, and 85K are positioned on the image forming stations Y, M, C, and K side. Then, the transfer belt 81 is pushed and brought into contact with the photosensitive drums 21 included in the image forming stations Y, M, C, and K, so that the primary transfer position TR1 is set between each photosensitive drum 21 and the transfer belt 81. Form. Then, by applying a primary transfer bias from the primary transfer bias generator to the primary transfer roller 85 at an appropriate timing, the toner images formed on the surfaces of the photosensitive drums 21 correspond respectively. A color image is formed by transferring to the surface of the transfer belt 81 at the primary transfer position TR1.

  On the other hand, when the monochrome mode is executed, among the four primary transfer rollers 85, the color primary transfer rollers 85Y, 85M, and 85C are separated from the image forming stations Y, M, and C facing each other, and the monochrome primary transfer is performed. By bringing only the roller 85K into contact with the image forming station K, only the monochrome image forming station K is brought into contact with the transfer belt 81. As a result, the primary transfer position TR1 is formed only between the monochrome primary transfer roller 85K and the image forming station K. Then, by applying a primary transfer bias to the monochrome primary transfer roller 85K from the primary transfer bias generator at an appropriate timing, the toner image formed on the surface of the photosensitive drum 21 is transferred to the primary transfer position TR1. Then, the image is transferred onto the surface of the transfer belt 81 to form a monochrome image.

  Further, the transfer belt unit 8 includes a downstream guide roller 86 disposed downstream of the monochrome primary transfer roller 85K and upstream of the driving roller 82. Further, the downstream guide roller 86 is formed between the primary transfer roller 85K and the photosensitive drum 21 at the primary transfer position TR1 formed by the monochrome primary transfer roller 85K contacting the photosensitive drum 21 of the image forming station K. It is configured to contact the transfer belt 81 on a common inscribed line.

  The drive roller 82 circulates and drives the transfer belt 81 in the direction of the arrow D81 in the figure, and also serves as a backup roller for the secondary transfer roller 121. A rubber layer having a thickness of about 3 mm and a volume resistivity of 1000 kΩ · cm or less is formed on the peripheral surface of the drive roller 82, and secondary transfer is omitted by grounding through a metal shaft. The conductive path of the secondary transfer bias supplied from the bias generation unit via the secondary transfer roller 121 is used. When the rubber layer having high friction and shock absorption is provided on the driving roller 82 in this way, the sheet enters the contact portion (secondary transfer position TR2) between the driving roller 82 and the secondary transfer roller 121. Is difficult to be transmitted to the transfer belt 81, and image quality deterioration can be prevented.

  The paper feed unit 11 includes a paper feed unit having a paper feed cassette 77 capable of stacking and holding sheets and a pickup roller 79 for feeding sheets one by one from the paper feed cassette 77. The sheet fed from the sheet feeding unit by the pickup roller 79 is fed to the secondary transfer position TR2 along the sheet guide member 15 after the sheet feeding timing is adjusted by the registration roller pair 80.

  The secondary transfer roller 121 is provided so as to be able to come into contact with and separate from the transfer belt 81 and is driven to come into contact with and separate from a secondary transfer roller drive mechanism (not shown). The fixing unit 13 includes a heating roller 131 that includes a heating element such as a halogen heater and is rotatable, and a pressure unit 132 that presses and biases the heating roller 131. The sheet on which the image has been secondarily transferred is guided to a nip formed by the heating roller 131 and the pressure belt 1323 of the pressure unit 132 by the sheet guide member 15, and in the nip, a predetermined value is formed. The image is heat-fixed at temperature. The pressure unit 132 includes two rollers 1321 and 1322 and a pressure belt 1323 stretched between them. The pressure belt 1323 stretched by the two rollers 1321 and 1322 is pressed against the peripheral surface of the heating roller 131 so that the nip formed by the heating roller 131 and the pressure belt 1323 can be widened. Yes. Further, the sheet thus subjected to the fixing process is conveyed to a paper discharge tray 4 provided on the upper surface portion of the housing body 3.

  Further, in this apparatus, a cleaner portion 71 is disposed to face the blade facing roller 83. The cleaner unit 71 includes a cleaner blade 711 and a waste toner box 713. The cleaner blade 711 removes foreign matters such as toner and paper dust remaining on the transfer belt 81 after the secondary transfer by bringing the tip of the cleaner blade 711 into contact with the blade facing roller 83 via the transfer belt 81. The foreign matter removed in this way is collected in a waste toner box 713. Further, the cleaner blade 711 and the waste toner box 713 are integrally formed with the blade facing roller 83. Therefore, when the blade facing roller 83 moves as will be described below, the cleaner blade 711 and the waste toner box 713 also move together with the blade facing roller 83.

Below, the line head 29 in this embodiment is demonstrated in detail based on figures.
FIG. 3 is a schematic perspective view of the line head 29 according to the present embodiment. FIG. 4 is a cross-sectional view of the line head 29 cut in the sub-scanning direction YY.
In FIG. 3, the line head 29 includes light emitting element groups 410 arranged in the main scanning direction XX. The light emitting element group 410 includes a plurality of light emitting elements 411. As shown in FIG. 4, the light emitting elements 411 irradiate light onto the surface 200 which is the surface to be scanned of the photoreceptor 2 </ b> Y charged by the charging unit 23 (see FIG. 1). An electrostatic latent image is formed.

  In FIG. 3, the line head 29 includes a case 420 having the main scanning direction XX as the first direction, and positioning pins 421 and screw insertion holes 422 are provided at both ends of the case 420. The line head 29 is positioned with respect to the photoreceptor 2Y shown in FIG. 4 by fitting the positioning pin 421 into a positioning hole formed in a photoreceptor cover (not shown). The photoconductor cover covers the photoconductor 2Y and is positioned with respect to the photoconductor 2Y. Further, the line head 29 is positioned and fixed with respect to the photosensitive member 2Y by screwing and fixing the fixing screw into the screw hole (not shown) of the photosensitive member cover via the screw insertion hole 422.

3 and 4, the case 420 holds two lens arrays 430a and 430b in which imaging lenses are arranged at a position facing the surface 200 of the photoconductor 2Y so as to overlap each other, and a lens is disposed inside the case 420. A light shielding member 440 and a head substrate 450 as a substrate are provided in the order close to the arrays 430a and 430b.
The head substrate 450 is a transparent glass substrate. A plurality of light emitting element groups 410 are provided on the back surface 452 of the head substrate 450 (the surface opposite to the front surface 451 facing the light shielding member 440 out of the two surfaces of the head substrate 450). . The plurality of light emitting element groups 410 are arranged two-dimensionally on the back surface 452 of the head substrate 450 two-dimensionally apart from each other in the main scanning direction XX and the sub-scanning direction YY as shown in FIG. . Here, the light emitting element group 410 is configured by two-dimensionally arranging a plurality of light emitting elements 411 as shown in a circled portion in FIG.

In the present embodiment, an organic EL is used as the light emitting element. That is, in this embodiment, the organic EL is disposed as the light emitting element 411 on the back surface 452 of the head substrate 450. Then, light emitted from each of the plurality of light emitting elements 411 toward the photoconductor 2 </ b> Y travels to the light shielding member 440 through the head substrate 450.
The light emitting element may be an LED. In this case, the substrate may not be a glass substrate, and the LED can be provided on the front surface 451.

3 and 4, the light blocking member 440 includes a plurality of light guide holes 4410 that correspond one-to-one to the plurality of light emitting element groups 410.
Light emitted from the light emitting elements 411 belonging to the light emitting element group 410 is guided to the pair of lens arrays 430a and 430b through the light guide holes 4410 corresponding to the light emitting element groups 410 on a one-to-one basis. Then, the light that has passed through the light guide hole 4410 is imaged as a spot on the surface 200 of the photoreceptor 2Y by the lens arrays 430a and 430b, as indicated by a two-dot chain line.

  As shown in FIG. 4, the back cover 470 is pressed against the case 420 via the head substrate 450 by the fixing device 460. The fixing device 460 has an elastic force that presses the back cover 470 toward the case 420, and the back cover 470 is pressed by the elastic force so that light does not leak from the inside of the case 420 and the case 420. It is sealed to prevent light from entering from the outside. A plurality of fixing devices 460 are provided in the main scanning direction XX of the case 420 shown in FIG. The light emitting element group 410 is covered with a sealing member 480.

FIG. 5 is a perspective view of the lens array 430a, and FIG. 6 is a partial sectional view of the lens array 430a in the main scanning direction XX. The configuration of the lens array 430a is the same as the configuration of the lens array 430b.
In FIG. 6, the lens array 430 a includes a lens substrate 431 as a base substrate and a lens portion 432.
The lens arrays 430a and 430b in FIG. 3 are fixed by fixing the lens substrate 431. In the lens arrays 430a and 430b, the lens portion 432 is disposed on the head substrate 450 side. Therefore, a plane that faces the surface on which the lens portion 432 is formed is disposed at a position that faces the photoreceptor 2Y.
In FIG. 6, the lens unit 432 includes a plurality of lenses 433. These lenses 433 are arranged as follows.

In FIG. 4, the lenses 433 of FIG. 6 provided in the lens arrays 430a and 430b form a pair, and share the optical axis indicated by the alternate long and short dash line in the drawing. Further, the pair of lenses 433 are arranged to face the plurality of light emitting element groups 410 shown in FIG.
The light emitted from each light emitting element 411 forms an image on the surface 200 of the photoreceptor 2Y by the lens 433 as indicated by a two-dot chain line.

A method for manufacturing the lens arrays 430a and 430b will be described below.
FIG. 7 is a flowchart showing a method for manufacturing the lens arrays 430a and 430b. The lens arrays 430a and 430b are formed using a mold (not shown) for forming the lens arrays 430a and 430b. In FIG. 7, the lens arrays 430a and 430b are manufactured in steps 1 (S1), which is a process of forming a first master, step 2 (S2), which is a process of forming a resin master, and a second master. Step 3 (S3), which is a process of forming a mold, Step 4 (S4), which is a process of forming a third master, and Step 5 (S5), which is a process of forming a mold.

  8 and 9 are sectional views showing a method for manufacturing the lens arrays 430a and 430b. The arrows connecting the processes in FIGS. 8 and 9 indicate that the same master is used at the starting point of the arrow and at the end point of the arrow. FIG. 8A shows Step 1 (S 1), which is a process for forming the first master disk 310. (B) shows step 2 (S2) which is the process of forming the resin master 320. (C) shows step 3 (S3) which is a process of forming the second masters 320a, 320b and 320c. (D) shows step 4 (S4) which is a process of forming the third master 330. FIG. 9E shows Step 5 (S5), which is a process of forming a mold 340 for forming the lens arrays 430a and 430b. (F) shows the process of forming the lens arrays 430a and 430b.

  In FIG. 8A, a first master 310 is obtained by forming a concave surface Q1 on a substrate 300 using a free-form surface processing machine. As the free-form surface processing machine, a 5-axis simultaneous control machine can be used.

  The length of the first master 310 in the first direction XX is preferably 1/3 to 1/4 of the length of the lens arrays 430a and 430b. For example, when the lengths of the lens arrays 430a and 430b are 300 mm, the length is about 100 mm.

  As a material of the substrate 300, iron, stainless steel, copper, nickel, or the like can be used. When diamond is used for the processing tool, it is preferable that the substrate 300 does not react with carbon, for example, nickel or oxygen-free copper is preferable. Further, for example, a substrate such as iron coated with nickel or oxygen-free copper may be used. In this case, parts such as nickel are processed.

  10A to 10C are views for explaining a method of forming alignment marks. An alignment mark Z1 as shown in the drawing is formed on a plane around the concave surface Q1 of the first master 310 of FIG.

  In FIG. 8B, a resin master 320 having a convex surface T1 is formed from the first master 310 by injection molding. By this injection molding, the alignment mark Z1 of the first master disk 310 is transferred to the resin master disk 320 of FIG. 10B to form the alignment mark Z2. In the present embodiment, three resin masters 320 are formed by injection molding.

  In FIG.8 (c), the both ends of the 1st direction XX shown with the broken line of the three resin original recordings 320 are each cut | disconnected by cutting. FIG. 10C shows one second master 320a formed by cutting both ends of the first direction XX surrounded by the broken line and the solid line of one resin master 320 by cutting. Similarly, both ends of the remaining two resin masters 320 are cut by cutting to obtain a second master 320b and a second master 320c. The second masters 320a, 320b, 320c have a convex surface T1.

  In the present embodiment, both end portions in the first direction XX of the second masters 320a, 320b, and 320c are cut, but one end portion in the first direction XX may be cut. That is, the second master disk 320a in FIG. 8C cuts only the second master disk 320b side, that is, the right side of the drawing, and the second master disk 320c cuts only the second master disk 320b side, that is, the left side of the drawing. Also good.

  In FIG. 8D, the second masters 320a, 320b, and 320c are arranged in the first direction XX on the substrate 600. The substrate 600 is preferably made of stainless steel having a small linear expansion coefficient in order to reduce the influence of heat caused by electroforming described later. The second masters 320a, 320b, and 320c are arranged so that the side opposite to the surface on which the convex surface T1 is formed faces the substrate 600. Before arranging, an adhesive is applied in advance to the surface where the second masters 320a, 320b, 320c and the substrate 600 are in contact.

  Next, in FIG. 8D, an ultraviolet curable resin as a resin that cures when irradiated with ultraviolet rays is filled in the gap SK1 between the two adjacent second masters.

  FIG. 11A is a diagram showing the second masters 320a, 320b, and 320c arranged on the substrate 600 in FIG. 8D, and is a diagram seen from the upper side of FIG. 8D. As shown in FIG. 11A, a gap SK1 between the adjacent second masters 320a and 320b and the adjacent second masters 320b and 320c is provided, so that the second masters 320a and 320a, 320b and 320c are arranged in the first direction XX.

  An alignment mark AM is formed on the substrate 600. For example, a CCD camera is used to image the vicinity of the alignment mark AM, and the position of the alignment mark Z2 formed on each of the second masters 320a, 320b, and 320c and the position of the alignment mark AM formed on the substrate 600. Are aligned on the substrate 600 such that the second masters 320a, 320b, and 320c are aligned. The step of aligning the positions of the second masters 320a, 320b, and 320c on the substrate 600 is performed before the adhesive applied between the substrate 600 and the second masters 320a, 320b, and 320c is cured.

  Next, ultraviolet rays are irradiated from the side opposite to the substrate 600 to cure the ultraviolet curable resin filled in the gap SK1.

  In this way, the third master 330 shown in FIG. 8D is constituted by the second masters 320a, 320b, and 320c fixed to the substrate 600 and integrated with the ultraviolet curable resin filled in the gap SK1. Form.

  In FIG. 9 (e), a nickel layer is formed from the third master 330 by electroforming to form a mold 340 having a concave surface Q2.

  In FIG. 9F, lens molds 340 are used to form lens arrays 430a and 430b having lenses 433 that form lenses 433 (see FIGS. 5 and 6) by injection molding.

  The concave surface Q2 of the mold 340 is two-dimensionally arranged side by side in the first direction XX and in the direction perpendicular to the first direction XX. The interval in which the concave surface Q2 in the mold 340 is aligned in the first direction XX and the interval in which the concave surface Q2 is aligned in the direction perpendicular to the first direction XX are the intervals in which the concave surface Q1 in the first master 310 is aligned in the first direction XX. And the same interval as those arranged in the direction perpendicular to the first direction XX. Accordingly, the positions of the plurality of concave surfaces Q1 in the first master 310 and the plurality of concave surfaces Q2 in the mold 340 correspond to each other.

  FIG. 11B is a diagram showing the mold 340. A range indicated by a broken line L in the figure indicates a range where the third master 330 is transferred. When the UV curable resin filled in the gap SK1 of the third master 330 in FIG. 8D contracts, a concave groove is formed in the gap SK1 of the third master 330 in FIG. Therefore, a streak SJ1 having a convex section is formed on the mold 340 formed from the third master 330 by electroforming.

  FIG. 11C shows the lens array 430a (430b). Since the convex streak SJ1 formed on the mold 340 is transferred by electroforming, a streak SJ2 having a concave cross section is formed in the lens array 430a (430b).

  On the other hand, when the gap SK1 is filled with the ultraviolet curable resin and the ultraviolet curable resin rises from the gap SK1, a streak SJ2 having a convex section is formed in the lens array 430a (430b).

  As described above, in the mold manufacturing method for forming the lens arrays 430a and 430b described in the present embodiment, the first master 310 having the concave surface Q1 formed in the first direction XX is formed by machining. A step of forming a resin master 320 having a convex surface T1 formed by injection molding from the first master 310, and a second master 320a by cutting the end of the resin master 320 in the first direction XX. , 320b, 320c, a step of forming the third master 330 by arranging the second masters 320a, 320b, 320c in the first direction XX, and electroforming from the third master 330. Forming a mold 340 (see FIGS. 8 and 9).

  According to the manufacturing method of the present embodiment, the resin master 320 is formed from the first master 310 by injection molding, and the resin master 320 having the same surface shape accuracy and surface roughness as the first master 310 is obtained. It is done. The second masters 320a, 320b, and 320c obtained by cutting off the end portions of the resin master 320 in the first direction XX have the same surface shape accuracy and surface roughness as the first master 310. The third master 330 is formed by arranging three second masters 320a, 320b, 320c in the first direction XX, and has the same surface shape accuracy and surface roughness as the second masters 320a, 320b, 320c. It has. A mold 340 for forming the lens arrays 430a and 430b is obtained from the third master 330 by electroforming. Thus, the mold 340 has the surface shape accuracy and surface roughness of the second masters 320a, 320b, and 320c transferred. Therefore, according to the method of manufacturing the mold 340 of the lens arrays 430a and 430b of the present embodiment, the surface shape accuracy and the surface roughness are equivalent to those of the first master 310.

  Further, since the first master 310 is shorter than the length in the first direction XX, the substrate 300 on which the first master 310 is formed can be shortened, and the time required for machining can be shortened. In addition, the need for exchanging tools and the like by machining is reduced. Therefore, a method for manufacturing the mold 340 of the lens arrays 430a and 430b in which the positional accuracy of the lenses is ensured can be obtained.

Further, the concave surface Q2 in the mold 340 of the lens arrays 430a and 430b of the present embodiment is manufactured so as to be two-dimensionally arranged.
Thereby, the manufacturing method of the type | mold 340 of the lens arrays 430a and 430b provided with the lens 433 of the several rows of 1st direction XX is obtained.

  Further, in the method of manufacturing the lens arrays 430a and 430b, the second masters 320a, 320b, and 320c are provided with an alignment mark Z2 (see FIG. 10C) corresponding to the position of the lens 433. The third master disc 330 in FIG. 11A is formed by arranging the second master discs 320a, 320b, and 320c with a gap SK1 in accordance with the alignment mark Z2.

  Thus, the second masters 320a, 320b, and 320c are arranged according to the alignment mark Z2, so that the convex surfaces T1 of the second masters 320a, 320b, and 320c can be easily aligned. Further, by providing a gap SK1 between the second masters 320a, 320b, and 320c, play occurs at the time of alignment, and alignment is easier to perform. Therefore, a method of manufacturing the mold 340 of the lens arrays 430a and 430b in which the positional accuracy of the lens 433 is ensured can be obtained.

Further, the gap SK1 in FIG. 11A is filled with resin.
Thus, the second masters 320a, 320b, and 320c are integrally formed by filling the gap SK1 between the second masters 320a, 320b, and 320c with the resin.

  In this embodiment, the present invention is applied to a color image forming apparatus. However, the application target is not limited to this, and the present invention can also be applied to a monochrome image forming apparatus that forms a so-called monochromatic image.

  Furthermore, the present invention can be applied not only to a dry toner but also to an image forming apparatus using a liquid toner in which toner particles are dispersed in a nonvolatile liquid carrier.

1 is a diagram illustrating an embodiment of an image forming apparatus. 1 is a diagram illustrating an electrical configuration of an image forming apparatus. The schematic perspective view of a line head. Sectional drawing which cut | disconnected the line head in the subscanning direction. The perspective view of a lens array. The fragmentary sectional view of the main scanning direction of a lens array. The flowchart figure showing the manufacturing method of a lens array. Sectional drawing showing the manufacturing method of a lens array. Sectional drawing showing the manufacturing method of a lens array. The figure explaining the method of forming an alignment mark. (A) is a figure which shows the 2nd original disk arranged on a board | substrate, (b) is a figure which shows a type | mold, (c) is a figure which shows a lens array.

Explanation of symbols

  29 ... Line head, 310 ... First master, 320 ... Resin master, 320a, 320b, 320c ... Second master, 330 ... Third master, 340 ... Mold, 410 ... Light emitting element group, 433 ... Lens, 430a , 430b ... lens array, 450 ... head substrate, Z2 ... alignment mark, Q1, Q2 ... concave surface, SK1 ... gap, T1 ... convex surface.

Claims (6)

Forming a first master having a concave surface in a first direction by machining;
Forming a resin master having a convex surface formed by injection molding from the first master;
Cutting the end of the resin master in the first direction to form a second master;
Disposing the second master in the first direction to form a third master;
Forming a mold by electroforming from the third master,
A method of manufacturing a lens array mold comprising: The second master is provided with an alignment mark,
2. The lens array mold according to claim 1, wherein the step of forming the third master includes forming the second master with a gap provided between the second masters according to the alignment marks. Production method.   The method of manufacturing a lens array mold according to claim 2, wherein the gap is filled with resin.   The method of manufacturing a lens array mold according to any one of claims 1 to 3, wherein the concave surface of the first master is disposed two-dimensionally.   A lens array formed by using a lens array mold manufactured by the method for manufacturing a lens array mold according to any one of claims 1 to 4. A lens array according to claim 5;
A line head comprising: a head substrate provided with two or more light emitting elements for emitting light imaged by lenses of the lens array.

Images