JP7294033B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having an exposure head.

A conventional image forming apparatus is provided with a connecting shaft that engages with an exposure head and an exposure head holding section that holds the exposure head, and integrates the exposure head and the exposure head holding section (for example, Japanese Unexamined Patent Application Publication No. 2002-200012). reference).

JP 2019-10755 A

However, in the conventional technique, there is a problem that the holding performance at the engaging portion between the connecting shaft as the connecting member and the exposure head is degraded, and the holding performance between the exposure head and the exposure head holding section is degraded. be.
SUMMARY OF THE INVENTION It is an object of the present invention to solve such a problem, and to improve the holding performance of an engaging portion of a connecting member and to improve the exposure head holding performance of an exposure head holding portion.

Therefore, the present invention provides an image forming unit having an image carrier, an exposure head for exposing the image carrier, a holding member having a first engaging portion and holding the exposure head, and the first a connecting member having a second engaging portion that engages with the engaging portion of the exposure head; and a fourth engaging portion that engages with the third engaging portion of the exposure head; a compression coil spring that biases toward the unit; and a restricting portion that restricts movement of the holding member. One end of the compression coil spring contacts the upper side of the seat portion of the holding member, The inner peripheral surface of the compression coil spring is engaged with the first engaging portion, the seat portion of the holding member is arranged to face in the short direction orthogonal to the longitudinal direction of the exposure head, and The restricting portion is positioned on the connecting member side of each of the seat portions, and is positioned on the inner peripheral surface of the compression coil spring that engages with the first engaging portion above each of the seat portions. A portion of the connecting member that is in surface contact with the connecting member downward from each of them and that contacts with the restricting portion is planar, and an upper portion of the first engaging portion and a lower portion of the second engaging portion are in a plane shape. When the lower portion of the third engaging portion and the upper portion of the fourth engaging portion are brought into contact and engaged with each other, the exposure head and the holding portion are below the compression coil spring. It is characterized by having a gap between members .

According to the present invention, it is possible to improve the holding performance of the engaging portion of the connecting member and to improve the exposure head holding performance of the exposure head holding portion.

Appearance perspective view of the printer in the embodiment Schematic side cross-sectional view showing the configuration of a printer in an embodiment A perspective view of an LED head unit in an embodiment FIG. 3 is a perspective view of a connecting portion between an LED head and an attachment in an embodiment; Cross-sectional view of springs and connections in an embodiment

An embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a printer according to the embodiment, and FIG. 2 is a schematic side sectional view showing the configuration of the printer according to the embodiment.
1 and 2, a printer 10 as an image forming apparatus is, for example, an electrophotographic color printer. In this embodiment, the printer 10 is described as a color printer, but it may be a monochrome printer.

The printer 10 is provided with a cover 10a which is supported so as to be openable and closable (rotatable).
A paper cassette 11 as a medium storage unit is disposed below the main body of the printer 10, and paper as a print medium is stored in the paper cassette 11. As shown in FIG.

A hopping roller 12 as a delivery member is provided at the front end of the paper cassette 11. As the hopping roller 12 rotates, the paper is separated one by one and delivered to a paper transport path Rt1 as a medium transport path. be A registration roller pair 13 is arranged in the paper transportation path Rt 1 , and the paper is conveyed by the registration roller pair 13 and sent to the image forming section 14 . As the paper, single paper, continuous paper, OHP sheet, envelope, copy paper, special paper, etc. can be used.

In the image forming section 14, image forming units 14K, 14Y, 14M, and 14C for black, yellow, magenta, and cyan are detachably arranged along the paper transport path Rt1 from the upstream side to the downstream side of the paper transport path Rt1. is set.

Each of the image forming units 14K, 14Y, 14M, and 14C includes a photosensitive drum 15 as an image carrier that is rotatably arranged, and is rotatably arranged in contact with the photosensitive drum 15. a charging roller as a charging device for uniformly charging the photosensitive drum 15, and is rotatably arranged in contact with the photosensitive drum 15; A developing roller as a developer bearing member that adheres toner to form a toner image as a developer image of each color that is a visible image; A toner supply roller as a developer supply member to be supplied, a development blade disposed in pressure contact with the development roller and serving as a developer regulating member for thinning the toner supplied from the toner supply roller to the development roller, the toner supply roller It has a toner cartridge or the like serving as a developer containing portion for supplying toner to the.

Above the photosensitive drums 15 in each of the image forming units 14K, 14Y, 14M, and 14C, an LED head unit 16 as an exposure device is attached to the back surface of the cover 10a and is arranged so as to hang down toward each photosensitive drum 15. is set.
The photosensitive drum 15 and the LED head unit 16 are arranged so as to extend in a direction orthogonal to the medium transport direction indicated by the arrow A in FIG.

Each LED head unit 16 includes an LED head 30 as an exposure head, and an LED head holder 31 as an exposure head holding portion for holding the LED head 30 and attaching it to the device main body. , the photosensitive drum 15 is exposed to form an electrostatic latent image according to the image data sent from the .

A transfer unit 18 is arranged below the photosensitive drum 15 in each of the image forming units 14K, 14Y, 14M, and 14C. The transfer unit 18 is stretched by a drive roller 18a as a first roller, a driven roller 18b as a second roller, and the drive roller 18a and the driven roller 18b. A transfer belt 19 that runs in the medium conveying direction indicated by a medium arrow A, and a transfer roller 17 as a transfer member that is rotatably opposed to each photosensitive drum 15 via the transfer belt 19 are provided.

A fixing device 20 as a fixing device is arranged downstream of the image forming section 14 in the paper transport path Rt1. The fixing device 20 includes a heating roller 20a as a first fixing member and a backup roller 20b as a second fixing member. and fixed to the paper, forming a color image on the paper.

The paper on which the color image is formed is discharged out of the main body of the apparatus from the discharge port formed in the housing and stacked on the stacker 22 on the cover 10a.

The printer 10 configured as described above is controlled by a control unit having control means such as a CPU (Central Processing Unit) and storage means such as a memory, and the entire operation is performed based on a control program (software) stored in the storage means. is controlled.

3A and 3B are perspective views of the LED head unit in the embodiment, FIG. 3A is an external perspective view of the LED head unit, and FIG. 3B is an exploded perspective view of the LED head unit.
In FIG. 3, the LED head unit 16 is arranged to extend in the longitudinal direction indicated by the arrow B in FIG. 3 perpendicular to the medium transport direction indicated by the arrow A in FIG. It has a head holder 31 , an attachment 32 and a spring 33 .

The LED head unit 16 is arranged so that the LED head 30 faces the photosensitive drum 15 shown in FIG. The photosensitive drums 15 shown in FIG. 2 are rotatably supported by drum supporting members provided on both sides of the image forming units 14K, 14Y, 14M, and 14C in the medium conveying direction.
The LED head 30 has a rod lens array held at a predetermined position facing the photosensitive drum 15 shown in FIG. 2 by a box-shaped holder.

The LED head 30 extends along the longitudinal direction of the photosensitive drum 15 shown in FIG. 2 (the longitudinal direction indicated by arrow B in FIG. 3 and perpendicular to the medium conveying direction indicated by arrow A in FIG. 2). and has a length (longitudinal length) sufficient to place both ends on the drum support member, and a width (longitudinal length) sufficient to accommodate the light emitting element substrate, the LEDs as the light emitting elements, and the rod lens array inside. length in the transverse direction).

The LED head holder 31 holds both ends in the longitudinal direction of the LED head 30 with holding portions 31c and 31d. It extends along the LED head 30 and has substantially the same length and width as the LED head 30 .
The LED head holder 31 is mounted inside the cover 10a (FIGS. 1 and 2) via mounting members 31a and 31b provided at both ends.

The attachment 32 as a holding member is arranged between the LED head 30 and the LED head holder 31 , holds the LED head 30 and is supported by the LED head holder 31 .
The attachment 32 extends along the longitudinal direction of the photosensitive drum 15 and has substantially the same length and width as the LED head 30 .

Springs 33 ( 33 a , 33 b ) as biasing members (compression springs) are compression coil springs arranged between the LED head holder 31 and the attachment 32 . The springs 33 (33a, 33b) urge the attachment 32 and the LED head 30 toward the photosensitive drums 15 of the image forming units 14K, 14Y, 14M, and 14C shown in FIG. 2 with the LED head holder 31 as a reference. ing.

The springs 33 (33a, 33b) are provided at two locations in the longitudinal direction of the LED head holder 31 and the attachment 32, corresponding to the connection portions 40a, 40b connecting the LED head 30 and the attachment 32, respectively. They are arranged as springs 33a and 33b.

As shown in FIG. 3B, the LED head unit 16 includes an LED head 30, a shaft 34 as a connecting member, an attachment 32, a spring 33, and an LED head holder 31 connected at connection portions 40a and 40b. . The shaft 34 is a connecting member that connects the LED head 30 and the attachment 32, and details thereof will be described later.

The LED head 30 and the attachment 32 are connected via a shaft 34 at connection portions 40a and 40b, and the attachment 32 to which the LED head 30 is connected has springs 33 (33a and 33b) between it and the LED head holder 31. It is held by the LED head holder 31 by engaging the convex portions 32a and 32b of the attachment 32 at the holding portions 31c and 31d.

FIG. 4 is a perspective view of the connecting portion between the LED head and the attachment in the embodiment. 4 shows a state in which the spring 33 shown in FIG. 3 is removed.
In FIG. 4 , the connecting portion 40 is a portion that connects the LED head 30 and the attachment 32 , and connects the LED head 30 and the attachment 32 via the shaft 34 .

Since the connection portion 40a and the connection portion 40b shown in FIG. 3 have the same configuration, one connection portion will be described as the connection portion 40. As shown in FIG. Arrow B in FIG. 4 indicates the longitudinal direction of the LED head 30 and the attachment 32 (the direction orthogonal to the medium transport direction).

5A and 5B are cross-sectional views of springs and connecting portions in the embodiment, FIG. 5A is a CC cross-sectional view in FIG. 4 is a DD cross-sectional view of 4 (a cross-sectional view of the LED head 30 and the attachment 32 in the lateral direction). 5 indicates the center of the connecting portion 40 (the spring 33 and the shaft 34).

In FIG. 5 , at the connecting portion 40 , the LED head 30 and the attachment 32 are connected via the shaft 34 .

The LED head 30 has a lens unit 301 , a positioning cam 302 and a shaft connecting portion 303 .
A lens unit 301 includes an LED and a rod lens array, and is arranged to face the photosensitive drum 15 shown in FIGS.

The positioning cam 302 is an adjusting member that adjusts the distance between the lens unit 301 and the photosensitive drum 15 shown in FIGS. The positioning cam 302 is an eccentric member, and is rotated by an adjusting jig to adjust the distance between the lens unit 301 and the photosensitive drum 15 .

The shaft connecting portion 303 is a portion to be fitted with the first end portion of the shaft 34, and is formed with a third engaging portion 304 that engages with a fourth engaging portion 341 of the shaft 34, which will be described later. . The shaft connecting portion 303 is formed to surround the shaft 34 .
The opening of the shaft connecting portion 303 has substantially the same shape as the fourth engaging portion 341 of the shaft 34 and is formed slightly larger so that the fourth engaging portion 341 of the shaft 34 can be inserted. ing.

The third engaging portion 304 is formed facing the shaft connecting portion 303 so as to protrude inward in the longitudinal direction of the LED head 30 and forms an opening of the shaft connecting portion 303 . The lower surface of the third engaging portion 304 engages with the upper surface of the fourth engaging portion 341 of the shaft 34 to restrict the movement of the shaft 34 toward the attachment 32 indicated by the arrow UP in the figure. do.

The third engaging portion 304 is formed in the longitudinal direction of the LED head 30 by rotating the shaft 34 inserted into the opening of the shaft connecting portion 303 by approximately 90 degrees from the direction of the LED head 30 indicated by the arrow DW in the figure. , and the fourth engaging portion 341 of the shaft 34 .

The attachment 32 has a shaft connecting portion 321 , a first engaging portion 322 , a restricting portion 325 and a spring receiving portion 326 .

The shaft connecting portion 321 is a portion to be fitted with the second end portion of the shaft 34 (the end portion opposite to the above-described first end portion), and is engaged with the second engaging portion 342 of the shaft 34 . A mating first engaging portion 322 is formed. As shown in FIG. 5A, the shaft connection portions 321 are arranged to face each other in the longitudinal direction of the attachment 32 .

The first engaging portion 322 is formed to protrude inwardly of the shaft connecting portion 321 in the longitudinal direction of the attachment 32 , and engages with the second engaging portion 342 of the shaft 34 so that the shaft 34 is shown in the drawing. Movement in the direction of the LED head 30 indicated by the middle arrow DW is restricted.

The first engaging portions 322 are arranged to face each other in the longitudinal direction of the attachment 32 (longitudinal direction of the LED head 30). A flat surface 322a is formed on each of the first engaging portions 322, and an inclined surface 322b is formed on the LED head 30 side (lower side) of each first engaging portion 322 so as to spread downward.

The first engaging portion 322 is supported by an elastic arm-shaped support portion 322c. When the support portion 322c is bent in the longitudinal direction of the attachment 32 and the LED head 30, the attachment 32 and the LED head 30 are bent. It is movable in the longitudinal direction of the head 30 .

Therefore, each first engaging portion 322 engages the attachment 32 and the LED by contacting the end portion (second engaging portion 342 ) of the shaft 34 inserted between the opposing first engaging portions 322 . It is configured to be separable in the longitudinal direction of the head 30 .

Further, each first engaging portion 322 is configured to approach due to the elasticity of the support portion 322c when contact with the end portion (second engaging portion 342) of the shaft 34 is released. .

The restricting portion 325 is in surface contact with the shaft 34, and is arranged to face the attachment 32 in the lateral direction, as shown in FIG. , restricts the lateral movement of the attachment 32 and restricts the rotation of the shaft 34 .

As shown in FIG. 5B, the spring receiving portion 326 as a seat portion is arranged so as to face the attachment 32 in the lateral direction (the lateral direction orthogonal to the longitudinal direction of the LED head 30). It is formed on the outside of 325, and is a bearing surface that abuts on an end portion 332 of the spring 33, which will be described later.

Since the spring receiving portion 326 is arranged to face the attachment 32 in the lateral direction, it does not come into contact with the support portion 322c that bends in the longitudinal direction of the attachment 32. As shown in FIG.

The shaft 34 as a connecting member is a shaft member that connects the LED head 30 and the attachment 32, has a substantially cylindrical shape, and has a planar portion facing the restricting portion 325. .

The shaft 34 has a main body portion 34a extending in the axial direction, and a fourth engaging portion 341 is formed at a first end (lower end) of the main body portion 34a, that is, the end on the LED head 30 side. A second engaging portion 342 is formed at the second end (upper end) of the main body portion 34a, that is, the end portion on the attachment 32 side.

The fourth engaging portion 341 engages with the third engaging portion 304 formed on the shaft connecting portion 303 of the LED head 30 in the longitudinal direction of the LED head 30, and the second engaging portion 342 , in the longitudinal direction of the LED head 30 , it engages with a first engaging portion 322 formed on the shaft connecting portion 321 of the attachment 32 to connect the LED head 30 and the attachment 32 .

The fourth engaging portions 341 are formed by protruding radially outward from the outer peripheral surface of the main body portion 34a across the axis of the main body portion 34a at two places in the circumferential direction of the lower end portion of the main body portion 34a, and are formed in a rectangular shape. It consists of a pair of protruding pieces with

In addition, the second engaging portions 342 are recesses that are recessed radially inward (toward the center) from the outer peripheral surface across the axis of the body portion 34a at two locations in the circumferential direction near the upper end portion of the body portion 34a. 342a is formed at the axially upper end of the shaft 34 from each recess 342a.

In the longitudinal direction of the LED head 30 and the attachment 32, the first engaging portion 322 of the attachment 32 enters the concave portion 342a, so that the lower portion of the second engaging portion 342 and the first engaging portion of the attachment 32 are brought into contact with each other. 322 are engaged.
The direction connecting the two recesses 342a and the direction connecting the two fourth engaging portions 341 are substantially the same.

Therefore, as shown in FIG. 5( a ), in the longitudinal direction of the LED head 30 and the attachment 32 , the fourth engaging portion 341 corresponds to the third engaging portion formed on the shaft connection portion 303 of the LED head 30 . 304 , the second engaging portion 342 engages with a first engaging portion 322 formed on the shaft connection portion 321 of the attachment 32 .

On the other hand, as shown in FIG. 5B, the shaft 34 does not engage with the LED head 30 and the attachment 32 in the lateral direction of the LED head 30 and the attachment 32 .

The spring 33 is arranged so as to abut on the spring receiving portion 326 of the attachment 32, and biases the attachment 32 in the direction indicated by the arrow DW in the figure.
The spring 33 has a base portion 331 , an end portion 332 , and an intermediate portion 333 connecting the base portion 331 and the end portion 332 .

The base portion 331 is a compression coil spring portion having a predetermined diameter.
The end portion 332 is a portion that contacts the spring receiving portion 326 of the attachment 32, is larger than the distance r between the outer walls of the first engaging portion 322 of the attachment 32, and has a diameter of the base portion 331 (diameter on the other end side). It is formed with a larger diameter.

As shown in FIG. 5(b), the end portion 332 is located outside the restricting portion 325 of the attachment 32 in the lateral direction of the attachment 32 (outside the connecting portion 40 in the lateral direction of the attachment 32 shown in FIG. 5(b)). (outer side with respect to the center line CL).

5(a), the end portion 332 is positioned outside the first engaging portion 322 of the attachment 32 in the longitudinal direction of the attachment 32 (in the longitudinal direction of the attachment 32 shown in FIG. 5(a)). outside of the connecting portion 40 with respect to the center line CL. At this time, the end portion 332 of the spring 33 restricts the outward movement of the first engaging portion 322 of the attachment 32 .

In this embodiment, the diameter of the end portion 332 is larger than the diameter of the base portion 331 , but the diameter is not limited to this and may be the same as the diameter of the base portion 331 .

The operation of the configuration described above will be described.
First, the operation of the printer 10 will be described with reference to FIG.
Upon receiving a print instruction from an external device, the printer 10 starts a printing operation and rotates the hopping roller 12 .

When the hopping roller 12 is rotated, the sheets accommodated in the sheet cassette 11 are separated one by one and delivered to the sheet transport path Rt1. The fed sheet is conveyed by the pair of registration rollers 13, sent to the image forming section 14, and attracted to the transfer belt 19 by electrostatic force. As the transfer belt 19 runs, the paper is conveyed between the photosensitive drums 15 and the transfer rollers 17 of the image forming units 14K, 14Y, 14M, and 14C.

On the other hand, in each of the image forming units 14K, 14Y, 14M, and 14C, the surface of the photosensitive drum 15 is uniformly charged by the charging roller, exposed by the LED head 30, and an electrostatic latent image is formed on the photosensitive drum 15. be done.

Further, the toner supplied from the toner cartridge to the toner supply roller is supplied to the development roller as the toner supply roller rotates, is thinned on the development roller by the development blade, and is formed into an electrostatic latent image on the photosensitive drum 15 . They are electrostatically adhered to form a toner image of each color.

A toner image of each color formed on each photosensitive drum 15 by electrostatic force generated by applying a predetermined voltage to each transfer roller 17 is successively superimposed and transferred onto the paper, resulting in a color toner image. is formed.

Subsequently, the paper is sent to the fixing device 20, and in the fixing device 20, the color toner image is heated by the heating roller 20a and pressed against the paper by the backup roller 20b to be fixed on the paper, forming a color image. be done. Then, the paper ejected from the fixing device 20 is transported along the paper transport path Rt<b>1 , is ejected outside the main body of the apparatus through the ejection port, and is stacked on the stacker 22 .

Next, a method of connecting the LED head 30, the LED head holder 31, and the attachment 32 of the LED head unit 16 shown in FIG. 3 will be described with reference to FIGS. 3 to 5. FIG. It is assumed that the operator connects the LED head 30 and the attachment 32 at the two connection portions 40a and 40b. A connection method at a single joint will be described below.

First, the operator inserts the fourth engaging portion 341 of the shaft 34 into the shaft connecting portion 303 of the LED head 30 (in the direction indicated by the arrow DW in FIG. 5).

At this time, the opening of the shaft connecting portion 303 of the LED head 30 has substantially the same shape as the fourth engaging portion 341 of the shaft 34 and is slightly larger. 341 can be inserted.

After inserting the fourth engaging portion 341 of the shaft 34 into the shaft connecting portion 303 of the LED head 30, the operator rotates the shaft 34 by approximately 90 degrees. As a result, the fourth engaging portion 341 of the shaft 34 engages with the third engaging portion 304 of the LED head 30, and movement of the shaft 34 toward the attachment 32 indicated by an arrow UP in FIG. 5 is restricted. be.

Next, the second engaging portion 342 of the shaft 34 engaged with the LED head 30 is inserted into the opening of the shaft connecting portion 321 of the attachment 32 (inserted in the direction indicated by the arrow UP in FIG. 5).

The second engaging portion 342 of the shaft 34 inserted into the opening of the shaft connecting portion 321 abuts on the inclined surface 322b of the attachment 32 at its tip, and spreads the first engaging portion 322 of the attachment 32. pass.
At this time, the first engaging portion 322 supported by the support portion 322c of the attachment 32 is expanded by bending the support portion 322c in the longitudinal direction of the attachment 32. As shown in FIG.

In this embodiment, the support portion 322c is arranged to face the attachment 32 in the longitudinal direction, and the spring receiving portion 326 is arranged to face the attachment 32 in the lateral direction, so that the attachment 32 is bent in the longitudinal direction. The supporting portion 322c and the spring receiving portion 326 do not come into contact with each other.

When the second engaging portion 342 of the shaft 34 passes through the first engaging portion 322 of the attachment 32, the bending of the support portion 322c of the attachment 32 is released, and the flat surface 322a of the first engaging portion 322 of the attachment 32 is released. and the second engaging portion 342 of the shaft 34 are engaged as shown in FIG. 5(a).

Thus, the fourth engaging portion 341 of the shaft 34 engages the third engaging portion 304 of the LED head 30, and the second engaging portion 342 of the shaft 34 and the first engaging portion of the attachment 32 are engaged. The LED head 30 and the attachment 32 are connected by engaging the flat surface 322 a of the joint portion 322 .

At this time, a predetermined gap d is formed between the LED head 30 and the attachment 32 . This is for facilitating connection between the LED head 30 and the attachment 32 .

Next, the operator brings the end portion 332 on the one end side of the spring 33 into contact with the spring receiving portion 326 of the attachment 32 as shown in FIG. are engaged with the holding portions 31c and 31d of the LED head holder 31, and the LED head 30, the LED head holder 31, and the attachment 32 are connected.

At this time, the inner peripheral surface of the end portion 332 on the one end side of the spring 33 is aligned with the outer wall (outer peripheral surface) of the first engaging portion 322 of the attachment 32 in the longitudinal direction of the attachment 32 (the longitudinal direction of the LED head 30). It engages and restrains the bending of the support part 322c.

That is, the first engaging portion 322 of the attachment 32 and the second engaging portion 342 of the shaft 34 are engaged at a position protruding toward the base portion 331 of the spring 33 from the contact surface of the spring receiving portion 326 of the attachment 32. do.

Therefore, the engagement between the second engaging portion 342 of the shaft 34 and the first engaging portion 322 of the attachment 32 will not be released, and the attachment 32 and the LED head 30 can be prevented from coming off. .

In this manner, the LED head 30, the LED head holder 31, and the attachment 32 are connected to assemble the LED head unit 16. FIG.

In this embodiment, since the inner peripheral surface of the end portion 332 of the spring 33 is in contact with the outer peripheral surface of the first engaging portion 322 of the attachment 32, the LED head 30 of the attachment 32 is held at the engaging portion of the shaft 34. It can improve performance.

In addition, since the movement of the first engaging portion 322 of the attachment 32 is suppressed by the end turn portion of the end portion 332 having a larger diameter than the base portion 331 of the spring 33, the effect on the function of the base portion 331 of the spring 33 can be suppressed.

Furthermore, by adjusting the height of the spring receiving portion 326 of the attachment 32 so that the end portion 332 of the spring 33 engages only with the tip portion of the first engaging portion 322 of the attachment 32, the end portion 332 It is also possible to suppress the number of turns of the end turn portion of the.

Further, by providing the spring receiving portion 326 in the attachment 32 at the connection portion with the LED head 30 , deformation of the attachment 32 when the attachment 32 is separated from the LED head 30 can be suppressed.
Furthermore, when the diameter of the end portion 332 of the spring 33 is formed larger than the diameter of the base portion 331, the biasing force of the spring 33 can be stabilized.

Further, by arranging the first engaging portion 322 of the attachment 32 to face the LED head 30 and the attachment 32 in the longitudinal direction, the rigidity of the first engaging portion 322 can be increased.
Furthermore, by arranging the first engaging portion 322 of the attachment 32 to face the LED head 30 and the attachment 32 in the longitudinal direction, the size of the LED head unit can be reduced, and the mounting space for the LED head unit can be easily saved. can be secured.

As described above, in the present embodiment, it is possible to improve the holding performance of the engaging portion of the connecting member and improve the LED head holding performance of the attachment.

In addition, an effect is obtained that the size of the LED head unit can be reduced.
In this embodiment, the image forming apparatus is described as a printer, but the image forming apparatus is not limited to this, and may be a copier, a facsimile machine, a multifunction peripheral (MFP), or the like.

10 Printer 11 Paper Cassette 12 Hopping Roller 13 Registration Roller Pair 14 Image Forming Section 14K, 14Y, 14M, 14C Image Forming Unit 15 Photosensitive Drum 16 LED Head Unit 17 Transfer Roller 19 Transfer Belt 20 Fixer 30 LED Head 31 LED Head Holder 32 Attachment 33 Spring 34 Shaft 40a, 40b Connecting portion 303, 321 Shaft connecting portion 304 Third engaging portion 322 First engaging portion 325 Regulating portion 326 Spring receiving portion 341 Fourth engaging portion 342 Second engaging portion Department

Claims (5)

an image forming unit having an image carrier;
an exposure head that exposes the image carrier;
a holding member having a first engaging portion and holding the exposure head;
a connecting member having a second engaging portion that engages with the first engaging portion and a fourth engaging portion that engages with a third engaging portion of the exposure head;
a compression coil spring that biases the exposure head toward the image forming unit;
a regulating portion that regulates the movement of the holding member;
has
one end of the compression coil spring is in contact with the upper side of the seat portion of the holding member, and an inner peripheral surface of the compression coil spring is engaged with the first engaging portion;
The seat portions of the holding member are arranged to face each other in a lateral direction perpendicular to the longitudinal direction of the exposure head,
The restricting portion is positioned on the connecting member side of each of the seat portions, and is positioned on the inner peripheral surface of the compression coil spring that engages with the first engaging portion above each of the seat portions. The portion of the connecting member that is in surface contact with the connecting member from the lower side of each portion and is in contact with the restricting portion is planar,
The upper portion of the first engaging portion and the lower portion of the second engaging portion contact and engage, and the lower portion of the third engaging portion and the upper portion of the fourth engaging portion contact. and a gap is formed between the exposure head and the holding member below the compression coil spring when the two are engaged. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the first engaging portions are arranged to face each other in the longitudinal direction of the exposure head. In the image forming apparatus according to claim 1 or claim 2 ,
The compression coil spring is
An image forming apparatus, wherein the diameter of the one end is larger than the diameter of the other end . In the image forming apparatus according to any one of claims 1 to 3 ,
The first engaging portion is movably supported in the longitudinal direction of the exposure head,
The compression coil spring is
An image forming apparatus, wherein an inner peripheral surface of the one end engages with an outer wall of the first engaging portion engaged with the second engaging portion in the longitudinal direction of the exposure head. In the image forming apparatus according to any one of claims 1 to 4,
An image forming apparatus, wherein the connecting member does not engage with the exposure head and the holding member in the lateral direction of the exposure head.

Images