JP4645690B2 - Image forming apparatus and manufacturing method thereof - Google Patents

Description

  The present invention relates to an image forming apparatus that exposes a photosensitive member such as a photosensitive drum with an exposure member having a plurality of blinking portions such as an LED head.

  As an image forming apparatus that exposes a photosensitive drum with an LED head, a distance in the optical axis direction between the LED head and the photosensitive drum (hereinafter also referred to as “working distance”) is maintained between the LED head and the photosensitive drum. Some spacers are provided. As such an image forming apparatus, conventionally, an eccentric cam is provided between the plate-shaped spacer and the LED head, and the working distance is adjusted by finely adjusting the distance between the spacer and the LED head in the optical axis direction. Is known (see Patent Document 1).

JP 2002-361931 A

  However, in the prior art, since the working distance is short, the size of the eccentric cam and the spacer has to be very small, and the accuracy and stroke of adjustment by the eccentric cam are limited. When such a restriction occurs, the working distance cannot be set with high accuracy, and the image quality may deteriorate.

  In addition, in the prior art, since the LED head is pressed against the photosensitive drum via the eccentric cam and the spacer, stress is applied to the LED head itself, and the LED head may be deformed. Further, when the LED head is manufactured by aluminum die casting so as to withstand deformation and the rigidity is increased, there is a problem that the LED head becomes large and the cost increases.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can accurately set a working distance and can suppress deformation of an LED head (exposure member).

  In order to solve the above-described problems, an image forming apparatus according to the present invention includes a photoconductor on which an electrostatic latent image is formed and an exposure that exposes the photoconductor having a plurality of blinking portions arranged in the axial direction of the photoconductor. A member, a support frame that supports the exposure member, a fixing unit that fixes the exposure member to the support frame, and a support frame that is provided between the support frame and the photoconductor, and is in contact with the photoconductor to support the support An interval holding member for holding an interval between the photoconductor and the exposure member via a frame; a pressing member for pressing the interval holding member against the photoconductor via the support frame; and the exposure member and the support frame And an adjustment member that moves the exposure member in the optical axis direction by adjusting a distance between the exposure member and the support frame.

  Here, when the photosensitive member is a photosensitive drum, the “axial direction of the photosensitive member” means an axial direction of the photosensitive member, and the photosensitive member includes a belt and a support shaft that rotatably supports the belt. In the case, it means the axial direction of the support shaft.

  The “fixing means” may be, for example, an elastic member, or a binding band or an adhesive that does not elastically deform. In the case of an elastic member, the adjustment of the distance between the exposure member and the photosensitive member can be performed by advancing and retracting a part of the adjustment member in the optical axis direction while pressing the exposure member toward the support frame with the elastic member. The exposure member can be moved in the optical axis direction. After the adjustment, the exposure member may be pressed and fixed to the support frame (adjustment member) with the elastic member as it is.

  When the fixing means is not elastically deformed, the distance between the exposure member and the photosensitive member is adjusted by, for example, pressing the exposure member toward the support frame with an air cylinder or the like while at least one of the adjustment members. By moving the part back and forth in the optical axis direction, the exposure member can be moved in the optical axis direction. After the adjustment, the adjustment member may be fixed to the support frame by a fixing means that does not elastically deform.

  According to the present invention, the interval holding member is provided between the support frame and the photosensitive member, and the adjustment member is provided between the exposure member and the support frame, thereby adjusting the interval between the exposure member and the support frame. Therefore, the gap holding member and the adjustment member can be formed larger than the conventional arrangement in which the gap holding member and the adjustment member are provided in a narrow gap between the exposure member and the photosensitive member. it can. As a result, the working distance can be set with high accuracy. Further, since the interval holding member is configured to hold the interval between the exposure member and the photosensitive member via the support frame, the pressing member presses the interval holding member against the photosensitive member via the support frame, The exposure member supported by the support frame via the fixing means is not subjected to a load from the pressing member, and deformation of the exposure member can be suppressed.

According to the present invention, since the degree of freedom of arrangement of the interval holding member and the adjustment member is increased, the interval holding member and the adjustment member can be appropriately sized. Thus, it becomes possible to set a working distance with a sufficient precision by making a space | interval holding member and an adjustment member moderate size.
Further, since the spacing member is pressed against the photoconductor via the support frame, deformation of the exposure member can be suppressed.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a cross-sectional view showing an overall configuration of a color printer as an example of an image forming apparatus. In the following description, the overall configuration of the color printer will be described first, and then the details of the features of the present invention will be described.

  In the following description, the direction will be described with reference to the user when using the color printer. That is, in FIG. 1, the left side toward the paper surface is “front side (front side)”, the right side toward the paper surface is “rear side (back side)”, the back side toward the paper surface is “left side”, and it faces the paper surface. Let the near side be the “right side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the color printer 1 includes a paper feeding unit 20 that supplies paper P, an image forming unit 30 that forms an image on the fed paper P, and an image formed in a main body housing 10. And a paper discharge unit 90 for discharging the paper P.

  An upper cover 12 that can be opened and closed relative to the main body housing 10 is provided on the upper portion of the main body housing 10 so as to be rotatable up and down around a hinge 12A provided on the rear side. An upper surface of the upper cover 12 serves as a paper discharge tray 13 for accumulating the paper P discharged from the main body housing 10, and a plurality of LED mounting members 14 for holding LED units 40 described later are provided on the lower surface. Yes.

  In addition, a main body frame 15 is provided in the main body housing 10 to detachably accommodate process cartridges 50 described later. The main body frame 15 is provided with a pair of metal side frames 15A (only one side is shown) provided on the left and right sides and a cross member 15B connecting the pair of side frames 15A on the front and rear. The main body frame 15 is fixed to the main body housing 10 or the like.

  The paper feeding unit 20 is provided in the lower part of the main body housing 10, and is a paper feeding tray 21 that is detachably attached to the main body housing 10, and a paper that conveys the paper P from the paper feeding tray 21 to the image forming unit 30. A supply mechanism 22 is mainly provided. The paper supply mechanism 22 is provided on the front side of the paper supply tray 21 and mainly includes a paper supply roller 23, a separation roller 24, and a separation pad 25.

  In the paper feed unit 20 configured in this way, the paper P in the paper feed tray 21 is separated one by one and sent upward, and passes through between the paper dust removal roller 26 and the pinch roller 27 in the process. After the powder is removed, the direction is changed backward through the conveyance path 28 and supplied to the image forming unit 30.

  The image forming unit 30 mainly includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing unit 80.

  The LED unit 40 is swingably supported by a connecting member 16 that is swingably connected to the LED mounting member 14, and is appropriately positioned and supported by a positioning member provided on the side frame 15A. The detailed structure of the LED unit 40 will be described later.

  The process cartridge 50 is arranged side by side in the front-rear direction between the upper cover 12 and the paper feeding unit 20, and a photosensitive drum 53 as an example of a photosensitive member on which an electrostatic latent image is formed, and a reference numeral are omitted. It comprises a known charger, developing roller, toner storage chamber and the like.

  The transfer unit 70 is provided between the paper feeding unit 20 and each process cartridge 50 and mainly includes a drive roller 71, a driven roller 72, a conveyance belt 73, and a transfer roller 74.

  The driving roller 71 and the driven roller 72 are arranged in parallel in a spaced manner in the front-rear direction, and a conveyance belt 73 formed of an endless belt is stretched between them. The outer surface of the conveyance belt 73 is in contact with each photosensitive drum 53. In addition, four transfer rollers 74 that sandwich the conveyor belt 73 between the photosensitive drums 53 are arranged inside the conveyor belt 73 so as to face the photosensitive drums 53. A transfer bias is applied to the transfer roller 74 by constant current control during transfer.

  The fixing unit 80 is disposed on the back side of each process cartridge 50 and the transfer unit 70, and includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In the image forming unit 30 configured as described above, first, the surface of each photosensitive drum 53 is uniformly charged by a charger and then exposed by each LED unit 40. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed on each photosensitive drum 53. Thereafter, toner is supplied to the electrostatic latent image from the developing roller, so that the toner image is carried on the photosensitive drum 53.

  Next, the paper P supplied onto the conveyor belt 73 passes between each photosensitive drum 53 and each transfer roller 74 disposed inside the conveyor belt 73, thereby forming the sheet P on each photosensitive drum 53. The toner image is transferred onto the paper P. Then, as the paper P passes between the heating roller 81 and the pressure roller 82, the toner image transferred onto the paper P is thermally fixed.

  The paper discharge unit 90 mainly includes a paper discharge side transport path 91 formed so as to extend upward from the outlet of the fixing unit 80 and to be reversed to the front side, and a plurality of pairs of transport rollers 92 that transport the paper P. I have. The paper P on which the toner image has been transferred and heat-fixed is transported through a paper discharge-side transport path 91 by a transport roller 92, discharged outside the main body housing 10, and accumulated in the paper discharge tray 13.

<Configuration of LED unit>
Next, the configuration of the LED unit 40 that is a characteristic part of the present invention will be described in detail. 2 is a front view showing the configuration of the LED unit, and FIG. 3 is an exploded perspective view (a) showing the left eccentric cam and an exploded perspective view (b) showing the right eccentric cam. . FIG. 4 is a front view showing a form in which a rough adjustment plate is sandwiched between the eccentric cam and the LED head.

  As shown in FIG. 2, the LED unit 40 includes an LED head 41 as an example of an exposure member, two wire springs 42 as an example of an elastic member (fixing means), a support frame 43, and a spacing member. The apparatus mainly includes two guide rollers 44 as an example and two eccentric cams 45 and 46 as an example of an adjustment member.

  The LED head 41 includes a plurality of LEDs 41A, a head frame 41B, and a lens array 41C. In the present embodiment, the blinking part is configured by a plurality of LEDs 41A and a lens array 41C as an example.

  The plurality of LEDs 41 </ b> A are arranged in a line in accordance with a predetermined pixel pitch in the left-right direction (the axial direction of the photosensitive drum 53), and are appropriately driven to emit light and direct light toward the photosensitive drum 53. It is comprised so that it may irradiate. Specifically, each LED 41 </ b> A receives a signal from a control device (not shown) based on image data to be formed, emits light, and exposes the photosensitive drum 53.

  The head frame 41B is made of resin, and supports a plurality of LEDs 41A at the lower part thereof. The head frame 41B is made of resin, so that the LED head 41 can be reduced in size and cost, and discharge from high-voltage components such as a charger is suppressed.

  The lens array 41C is an array of a plurality of Selfoc lenses (registered trademark). The lens array 41C extends in the arrangement direction of the LEDs 41A and leaves the both ends of the lower surface of the head frame 41B. It is fixed to.

  The wire spring 42 is a linear tension spring formed in a substantially V shape, and urges the LED head 41 toward the support frame 43. Specifically, the wire spring 42 has a V-shaped main body portion 42A, an action portion 42B formed at the lower end of the main body portion 42A, and an engaging claw portion 42C formed at the upper end of the main body portion 42A. ing.

  The main body 42A is bent and formed in a V shape so as to expose operation portions (cross grooves 45C and 46C described later; see FIG. 3) of eccentric cams 45 and 46 described later.

  The action part 42B is a part that applies a pressing force to the LED head 41, and is in contact with a part of the lower surface of the head frame 41B that is on the outer side in the left-right direction from the plurality of LEDs 41A (lens array 41C). Further, the action part 42B is formed in a V shape by being bent upward and then bent downward, whereby the contact portion between the action part 42B and the head frame 41B becomes substantially dotted. Yes.

  The engaging claw portion 42C is formed in a V shape so as to be hooked on the upper surface of an engaging pin portion 43C of the support frame 43 described later.

  The support frame 43 supports the LED head 41 via the wire spring 42, and includes a base portion 43A extending in the left-right direction and a pair of extending portions 43B extending downward from both ends of the base portion 43A. Configured.

  In the base portion 43A, two engaging pin portions 43C that support the wire spring 42 and two bearing portions 43D and 43E that rotatably support the eccentric cams 45 and 46 are formed at symmetrical positions. On the upper surface of the base portion 43A, two coil springs 47 as an example of a pressing member that presses the support frame 43 toward the lower photosensitive drum 53 are disposed at symmetrical positions. The support frame 43 is pressed by the two coil springs 47 with a good balance in the left-right direction.

  The extending portion 43B is formed with a length protruding downward from the lower surface of the LED head 41 supported by the base portion 43A via the wire spring 42, and a guide roller 44 can be rotated at the lower end portion thereof. A shaft portion 43F is provided for support.

  The guide roller 44 is a cylindrical member, and is installed at a predetermined distance from the LED head 41 by being rotatably provided on the shaft portion 43F at the lower end portion of the extending portion 43B of the support frame 43. Yes. The guide roller 44 is pressed against the photosensitive drum 53 by the urging force from the coil spring 47 described above being transmitted through the support frame 43, and is rotated by the photosensitive drum 53. The guide roller 44 is in contact with the photosensitive drum 53, so that the distance between the photosensitive drum 53 and the LED head 41 supported by the support frame 43 in the optical axis direction even when the photosensitive drum 53 is eccentric. (Working distance S) is maintained.

  The guide roller 44 may be in contact with a photosensitive layer (exposed layer) on the surface of the photosensitive drum 53, or may be in contact with a region outside the photosensitive layer in the left-right direction (region without the photosensitive layer). May be.

  The eccentric cams 45 and 46 are disposed between the LED head 41 and the base portion 43A of the support frame 43, and are configured to press the LED head 41 in the optical axis direction while receiving the urging force of the wire spring 42. Has been. Specifically, the eccentric cams 45 and 46 are disposed at positions on the upper surface of the head frame 41B that are in contact with a portion on the outer side in the left-right direction with respect to the plurality of LEDs 41A (lens array 41C), and the urging force of the wire spring 42 is set. It arrange | positions so that it may overlap with the action part 42B of the wire spring 42 seeing from a direction (up-down direction).

  The left eccentric cam 45 of the pair of eccentric cams 45, 46 is configured to press the LED head 41 at two locations as shown in FIG. 3A, and the right eccentric cam 46 is As shown to 3 (b), it is comprised so that the LED head 41 may be pressed in one place. That is, there are only three contact portions between all the eccentric cams 45 and 46 and the LED head 41.

  Specifically, as shown in FIG. 3A, the left eccentric cam 45 includes two cylindrical portions 45A arranged concentrically, and each cylindrical portion 45A at a position eccentric from the center of each cylindrical portion 45A. It has one shaft part 45B to be connected.

  The shaft portion 45B of the eccentric cam 45 is rotatably supported by the bearing portion 43D with a predetermined astringency (rotational resistance) by being fitted to the C-shaped bearing portion 43D of the support frame 43. Here, the astringency between the shaft portion 45 </ b> B and the bearing portion 43 </ b> D is set such that the eccentric cam 45 does not rotate with the urging force of the wire spring 42.

  Further, a cross groove 45C whose center coincides with the center of the shaft portion 45B is formed on the end surface of the cylindrical portion 45A of the eccentric cam 45. Then, by engaging a plus driver in the cross groove 45C and rotating the plus driver by a predetermined amount with a force larger than the urging force of the wire spring 42, the eccentric cam 45 rotates by a predetermined amount with respect to the support frame 43, It will be maintained in that position.

  As shown in FIG. 3B, the right eccentric cam 46 is formed in a shape obtained by removing one cylindrical portion 45A from the left eccentric cam 45. That is, the right eccentric cam 46 includes a cylindrical portion 46A, a shaft portion 46B, and a cross groove 46C that have the same configuration as the left eccentric cam 45. Then, the shaft portion 46B of the eccentric cam 46 is rotatably supported by the bearing portion 43E with the same astringency as described above by being fitted to the substantially cylindrical bearing portion 43E of the support frame 43.

  In the LED unit 40 configured as described above, the support roller 43 is positioned at a predetermined position with respect to the photosensitive drum 53 by the guide roller 44 coming into contact with the photosensitive drum 53 as shown in FIG. become. Further, the LED head 41 is pressed against the eccentric cams 45 and 46 supported by the support frame 43 positioned as described above, whereby the LED head 41 is positioned relative to the photosensitive drum 53.

  Then, by appropriately operating the eccentric cams 45 and 46 in this state, the LED head 41 moves back and forth with respect to the support frame 43, and the working distance S is finely adjusted. Since the working distance S varies greatly due to the influence of manufacturing errors of the guide roller 44, the support frame 43, the eccentric cams 45 and 46, and the LED head 41, the working distance S is desired for the adjustment width of the eccentric cams 45 and 46. May not be possible. In this case, as shown in FIG. 4, a coarse adjustment plate 48 for coarse adjustment of the working distance S may be appropriately provided between the eccentric cams 45 and 46 and the LED head 41.

<Color printer manufacturing method>
Next, a method for manufacturing the color printer 1 will be described. In the drawings to be referred to, FIG. 5 is a front view (a) showing the first step and the second step, a front view (b) showing the third step, and a front view (c) showing the fourth step.

  As shown in FIG. 5A, first, the LED head 41 is set on the first jig 100. Here, the first jig 100 includes a bottom wall portion 101 opposed to the plurality of LEDs 41A arranged in a row below the LED head 41, and a pair of members that protrude upward from the bottom wall portion 101 and support the LED head 41. And a support portion 102. The bottom wall 101 is provided with two first optical sensors 110 that receive light emitted from two LEDs 41A located at both ends of the plurality of LEDs 41A arranged in a line.

  Next, each LED 41A emits light to the first optical sensor 110, and the amount of deviation of the focal position of the light is measured (first step). Then, based on the measured focal position shift amount, it is determined whether or not to install the rough adjustment plate 48 (second step).

  Specifically, in the second step, for example, the distance between the surface of the first optical sensor 110 (corresponding to the surface of the photosensitive drum 53) and the LED head 41 is measured based on the focal position shift amount. When this distance is larger than the desired working distance S by a predetermined value (a value within the range of the adjustment width of the eccentric cams 45 and 46), it is determined that the rough adjustment plate 48 is not installed. Further, when the distance between the first optical sensor 110 and the LED head 41 is larger than the desired working distance S plus the predetermined value, it is determined that the rough adjustment plate 48 is installed.

  Thereafter, the LED head 41 is removed from the first jig 100, and as shown in FIG. 5B, a rough adjustment plate 48 is appropriately disposed on the support frame 43 assembled with the eccentric cams 45 and 46, and the LED The head 41 is assembled by the wire spring 42. Further, the guide roller 44 is assembled to the support frame 43 (third step). Here, the order of assembling the guide roller 44 may be before or after the LED head 41 is assembled to the support frame 43.

  And the LED unit 40 assembled in this way is set to the 2nd jig | tool 200, as shown in FIG.5 (c). Here, the second jig 200 includes a bottom wall portion 201 that faces the plurality of LEDs 41 </ b> A, and a pair of support portions 202 that protrude upward from the bottom wall portion 201 and support the support frame 43. . The bottom wall 201 is provided with two second optical sensors 210 that receive light emitted from two LEDs 41A located at both ends of the plurality of LEDs 41A arranged in a line, and a guide roller 44 and A reference surface 201A to be in contact with is formed.

  Then, the eccentric cams 45 and 46 that receive the urging force from the wire spring 42 while irradiating light from the respective LEDs 41A of the LED unit 40 to the second optical sensor 210 with the guide roller 44 in contact with the reference surface 201A. To adjust the focal position of the light to a predetermined position with respect to the reference surface 201A (fourth step). As a result, the LED head 41 is positioned with respect to the reference surface 201A corresponding to the surface of the photosensitive drum 53, and the working distance S is set to a desired value.

  Thereafter, as shown in FIG. 1, the LED unit 40 is connected to the upper cover 12 via the coil spring 47, the connecting member 16, and the LED mounting member 14, and the paper feeding unit 20, the image forming unit 30, and the paper discharge unit. The color printer 1 is manufactured by attaching each component constituting the unit 90 and the like in the main body housing 10.

According to the above, the following effects can be obtained in the present embodiment.
The guide roller 44 is provided on the support frame 43 and the eccentric cams 45 and 46 are disposed between the LED head 41 and the support frame 43 so that the distance between the LED head 41 and the support frame 43 is adjusted. Since it is configured, the guide roller 44 and the eccentric cams 45 and 46 can be formed larger than the conventional arrangement in which the spacer and the eccentric cam are provided in a narrow gap between the LED head and the photosensitive drum. Therefore, the accuracy of adjustment by the eccentric cams 45 and 46 can be improved, and the stroke of the LED head 41 that moves by pressing the eccentric cams 45 and 46 can be increased. In this way, the working distance S can be set with high accuracy. Furthermore, since a large rotatable guide roller 44 can be employed as the spacing member instead of a conventional thin spacer, wear of the guide roller 44 or the photosensitive drum 53 can be suppressed.

  Further, since the coil spring 47 presses the guide roller 44 against the photosensitive drum 53 via the support frame 43, a load from the coil spring 47 is applied to the LED head 41 supported by the support frame 43 via the wire spring 42. Therefore, the deformation of the LED head 41 can be suppressed. And by setting it as the structure which does not give load to LED head 41 in this way, since LED head 41 can be formed with resin like this embodiment, size reduction and cost reduction of LED head 41 are achieved. In addition, it is possible to suppress discharge from a high voltage component such as a charger.

  Since the rough adjustment plate 48 is appropriately provided between the eccentric cams 45 and 46 and the LED head 41, the operating distance S cannot be set to a desired value with the adjustment width of the eccentric cams 45 and 46 due to manufacturing errors or the like. However, the working distance S can be set to a desired value by the rough adjustment plate 48.

  Since the LED head 41 is supported by the support frame 43 via the wire spring 42, the operating distance S can be adjusted by operating the eccentric cams 45 and 46 in a state where the assembly of the LED unit 40 is completed.

  Since the action part 42B of the wire spring 42 and the eccentric cams 45, 46 are arranged on the outer side in the left-right direction with respect to each LED 41A of the LED head 41, both end parts of the LED head 41 are the action part 42B of the wire spring 42 and the eccentric cam 45. , 46 and the LED head 41 can be stably supported. Further, since the acting portion 42B of the wire spring 42 and the eccentric cams 45, 46 are arranged so as to overlap each other when viewed from the biasing direction of the wire spring 42, the pressing force applied to the LED head 41 from the eccentric cams 45, 46 can be reduced. The urging force of the wire spring 42 can be substantially matched in the left-right direction, and the LED head 41 can be prevented from being bent.

  Since the wire spring 42 is bent so as to expose the cross grooves 45C of the eccentric cams 45, 46, the eccentric cams 45, 46 can be easily operated.

  Since there are only three contact portions between the eccentric cams 45 and 46 and the LED head 41, the LED head 41 biased toward the eccentric cams 45 and 46 can be stably supported at three points. it can.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the embodiment, the wire spring 42 is employed as the elastic member. However, the present invention is not limited to this, and for example, a leaf spring 300 as shown in FIGS. 6A and 6B may be employed. Specifically, the leaf spring 300 includes a main body portion 310 that extends in the vertical direction, an action portion 320 that is formed at the lower end of the main body portion 310 and presses the LED head 41 toward the support frame 43, and an upper end of the main body portion 310. And an engaging claw 330 that engages with the upper surface of the support frame 43.

  The main body 310 is formed with an opening 311 that exposes the cross grooves 45C and 46C of the eccentric cams 45 and 46. Thereby, the eccentric cams 45 and 46 can be easily operated.

  In the above-described embodiment, the eccentric cams 45 and 46 are employed as the adjusting members. However, the present invention is not limited to this, and for example, a screw 400 as shown in FIG. Specifically, the screw 400 is screwed into the support frame 43 so as to penetrate up and down the support frame 43 with the operation portion (screw head for operation) facing upward.

  One screw 400 is arranged on the right side of the support frame 43 (see FIG. 7B), and two screws 400 arranged in the front-rear direction are arranged on the left side of the support frame 43 at a predetermined distance from each other (see FIG. 7). 7 (c)). More specifically, each screw 400 is disposed on the outer side in the left-right direction with respect to the plurality of LEDs 41A.

  A contact member 410 having a larger diameter than the lower end surface of the screw 400 is joined to the lower end of the screw 400. As a result, as shown in FIG. 7B, on the right side of the support frame 43, the action portion 42B of the wire spring 42 (specifically, the LED head 41 and the contact portion TP between the screw 400 and the LED head 41). The abutting part) is formed smaller.

  And the action part 42B formed small in this way is arrange | positioned in the range T1 of the contact part TP. Therefore, the pressing force applied to the LED head 41 from the contact member 410 of the screw 400 and the urging force of the wire spring 42 can be matched more in the left-right direction, and the LED head 41 can be further prevented from being bent. Moreover, since the pressing force from the contact member 410 and the urging force of the wire spring 42 match in the front-rear direction, the LED head 41 can be prevented from tilting in the front-rear direction.

  Further, as shown in FIG. 7C, on the left side of the support frame 43, the action portion 42B (specifically, the portion in contact with the LED head 41) is more than the range T2 between the two contact portions TP. Is formed small. And the action part 42B formed small in this way is arrange | positioned in the range T2 between the two contact parts TP.

  Therefore, the pressing force applied to the LED head 41 from the two abutting members 410 and the urging force of the wire spring 42 can be matched more in the left-right direction, and the LED head 41 can be further prevented from being bent. Moreover, since the action part 42B of the wire spring 42 is disposed between the two contact members 410 arranged in the front-rear direction, the LED head 41 can be prevented from tilting in the front-rear direction.

  In FIG. 7C, the same effect as described above can be obtained even if the action portion 42B of the wire spring 42 is disposed within the range of one of the two contact portions TP. .

  In the embodiment, the pulling spring (wire spring 42) that pulls the LED head 41 toward the support frame 43 is employed as the elastic member. However, the present invention is not limited to this, and a pressing spring that presses the LED head against the support frame is employed. May be. Specifically, for example, as shown in FIG. 8, a pedestal portion 43G that extends inward in the left-right direction from the extension portion 43B of the support frame 43 according to the embodiment and faces the lower surface of the LED head 41 is provided. A coil spring 500 may be provided between the upper surface of the pedestal portion 43G and the lower surfaces of both end portions of the LED head 41. Even in this case, since the LED head 41 is pressed toward the support frame 43 (base portion 43A) by the coil spring 500, the LED head 41 is arranged between the LED head 41 and the support frame 43 as in the above embodiment. The LED head 41 can be advanced and retracted in the optical axis direction by the eccentric cams 45 and 46 provided.

  Further, as shown in FIG. 8, instead of the guide roller 44 according to the embodiment, a sliding contact portion 43H that protrudes downward from the lower surface of the pedestal portion 43G and is in sliding contact with the photosensitive drum 53 is provided as a spacing member. May be. That is, a non-rotating member may be employed as the spacing member. However, when the rotatable guide roller 44 is employed as in the above-described embodiment, it is desirable to employ the guide roller 44 because wear of the guide roller 44 or the photosensitive drum 53 is suppressed. The spacing member may be provided on a frame that rotatably supports the photosensitive drum 53.

  In the embodiment, the eccentric cams 45 and 46 are provided on the support frame 43, but the present invention is not limited to this, and may be provided on the LED head 41 as shown in FIG. Specifically, on the upper surface of the LED head 41, bearing portions 41D and 41E similar to the bearing portions 43D and 43E (see FIG. 3) according to the embodiment are provided, and these bearing portions 41D and 41E Similar eccentric cams 45 and 46 may be assembled. In this case, the coarse adjustment plate 48 may be appropriately provided between the support frame 43 and the eccentric cams 45 and 46. Even in this case, when the eccentric cams 45 and 46 are rotated, the eccentric cams 45 and 46 press the support frame 43 (or the coarse adjustment plate 48), and the LED head 41 can be advanced and retracted in the optical axis direction. it can.

  In the above embodiment, the elastic member (wire spring 42) is used as the fixing means, but the present invention is not limited to this, and a binding band or an adhesive that does not elastically deform may be used. When the fixing means is not elastically deformed in this way, for example, the wire spring 42 shown in FIG. 5C may be used as a jig at the time of manufacture.

  That is, as shown in FIG. 5C, after adjusting the working distance S using the biasing force of the wire spring 42 in the fourth step, the LED head 41 is fixed to the support frame 43 with a binding band or an adhesive. Thereafter, the wire spring 42 may be removed. In this case, it is desirable that the eccentric cams 45 and 46 are fixed to at least one of the LED head 41 and the support frame 43 with an adhesive so that the subsequent rotation is impossible. According to this, since the eccentric cams 45 and 46 are not moved after the adjustment of the working distance S, the working distance S can be reliably maintained at a desired value.

  In addition to the wire spring 42, a plate spring, an air cylinder, or the like can be used as a jig for pressing the LED head 41 toward the support frame 43 when the working distance S is adjusted.

  In the embodiment, the LED head 41 including the plurality of LEDs 41A arranged in a line in the left-right direction is used as the exposure member, but the present invention is not limited to this. For example, you may employ | adopt as an exposure member the LED head which has several rows arranged in the front-back direction in the left-right direction. In addition, a plurality of blinking parts are configured by one light emitting element such as an LED or a fluorescent lamp and a plurality of liquid crystal or PLZT element optical shutters arranged in the left-right direction outside the light emitting element. It is good also as what has an exposure member. Further, the light source of the exposure member is not limited to the LED, but may be an EL (electroluminescence) element or a phosphor.

In the embodiment, the coil spring 47 is employed as the pressing member, but the present invention is not limited to this, and a torsion spring, a disc spring, or the like may be used.
In the above-described embodiment, only three contact portions between the eccentric cams 45 and 46 and the LED head 41 are provided. However, the present invention is not limited to this, and four or more contact portions may be provided. If it is formed in a planar shape, it may be two places.

  In the above-described embodiment, the cross grooves 45C and 46C are employed as the operation unit. However, the present invention is not limited to this, and a linear groove that engages with a flathead screwdriver or a polygonal wrench such as a hexagon wrench can be engaged. Polygonal holes, protrusions that can be gripped with pliers or the like may be employed.

In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.
In the above-described embodiment, the photosensitive drum 53 is employed as the photosensitive member. However, the present invention is not limited to this, and for example, a belt-shaped photosensitive member may be employed.

1 is a cross-sectional view illustrating an overall configuration of a color printer as an example of an image forming apparatus. It is a front view which shows the structure of an LED unit. They are an exploded perspective view (a) which shows a left eccentric cam, and an exploded perspective view (b) which shows a right eccentric cam. It is a front view which shows the form which pinched | interposed the rough adjustment board between the eccentric cam and the LED head. They are the front view (a) which shows a 1st process and a 2nd process, the front view (b) which shows a 3rd process, and the front view (c) which shows a 4th process. It is the front view (a) which shows the form which employ | adopted the leaf | plate spring as an elastic member, and XX sectional drawing (b) of Fig.6 (a). It is the front view (a) which shows the form which employ | adopted the screw as an adjustment member, YY sectional drawing (b) of Fig.7 (a), and ZZ sectional drawing (c) of Fig.7 (a). It is a front view which shows the form which employ | adopted the coil spring which is a press spring as an elastic member. It is a front view which shows the form which provided the eccentric cam in the LED head.

Explanation of symbols

1 Color printer 40 LED unit 41 LED head 41A LED
41B head frame 42 wire spring 42B action part 43 support frame 43A base part 43B extension part 43C engagement pin part 43D bearing part 43E bearing part 43F shaft part 44 guide roller 45 eccentric cam 45C cross groove 46 eccentric cam 46C cross groove 47 coil Spring 48 Coarse adjustment plate 53 Photosensitive drum 100 First jig 110 First optical sensor 200 Second jig 201A Reference surface 210 Second optical sensor

Claims (12)

A photoreceptor on which an electrostatic latent image is formed;
An exposure member having a plurality of blinking portions arranged in the axial direction of the photoconductor to expose the photoconductor;
A support frame for supporting the exposure member;
Fixing means for fixing the exposure member to a support frame;
An interval holding member that is provided between the support frame and the photoconductor, contacts the photoconductor, and holds an interval between the photoconductor and the exposure member via the support frame;
A pressing member that presses the spacing member against the photoreceptor via the support frame;
An adjusting member that is disposed between the exposure member and the support frame and moves the exposure member in the optical axis direction by adjusting a distance between the exposure member and the support frame; An image forming apparatus. Between the adjustment member and the exposure member, or between the adjustment member and the support frame,
The image forming apparatus according to claim 1, further comprising a coarse adjustment plate for coarsely adjusting an interval between the exposure member and the photosensitive member.   The image forming apparatus according to claim 1, wherein the fixing unit is an elastic member.   The action portion of the elastic member that applies force to the exposure member and the adjustment member are disposed on the outer side in the axial direction than the blinking portion of the exposure member, and overlap with each other when viewed from the biasing direction of the elastic member. The image forming apparatus according to claim 3, further comprising:   The image forming apparatus according to claim 4, wherein the elastic member is a leaf spring, and an opening is formed to expose an operation portion of the adjustment member.   The image forming apparatus according to claim 4, wherein the elastic member is a wire spring and is bent so as to expose an operation portion of the adjustment member. The contact portion with all of the adjusting member and the exposure member and the support frame, are three places der,
One of the three locations is located on one end side of the exposure member in the axial direction, two locations are located on the other end side, and the two locations are separated in a direction perpendicular to the axial direction and the optical axis direction. the image forming apparatus according to any one of claims 1 to 5, characterized in that there. The action portion of the elastic member is formed smaller than the contact portion between the adjustment member and the exposure member or the support frame,
The image forming apparatus according to claim 4, wherein the action portion is disposed within a range of the contact portion. The adjustment member is disposed on one end side and the other end side in the axial direction of the exposure member,
The adjustment member on the one end side has two abutting portions that abut against the exposure member or the support frame,
The two abutting portions are disposed apart in a direction orthogonal to the axial direction and the optical axis direction;
The action portion of the elastic member that applies a force to the exposure member is formed to be smaller than a range between the two contact portions, and is disposed between the two contact portions. The image forming apparatus according to claim 3 .   The image forming apparatus according to claim 1, wherein the adjustment member is an eccentric cam. A method of manufacturing an image forming apparatus according to claim 2,
A first step of measuring the amount of deviation of the focal position of the light by setting the exposure member on a first jig having a first optical sensor and irradiating the first optical sensor with light from the exposure member;
A second step of determining whether or not to install the rough adjustment plate based on the shift amount of the focal position;
The exposure member is removed from the first jig, the interval holding member is assembled to the support frame, and at least the adjustment member of the adjustment member and the rough adjustment plate is disposed between the exposure member and the support frame. A third step to install;
With the spacing member in contact with the reference surface of the second jig having the second optical sensor, the support frame is set on the second jig, and the exposure member is pressed toward the support frame. And a fourth step of adjusting the focal position of the light to a predetermined position relative to the reference plane by irradiating the second photosensor with light from the exposure member and operating the adjustment member. A method for manufacturing an image forming apparatus. 12. The method of manufacturing an image forming apparatus according to claim 11, wherein after the fourth step, the adjustment member is fixed to at least one of the exposure member and the support frame with an adhesive.

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