JP3110771B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus having a support mechanism and a positioning mechanism for an optical writing unit.

[0002]

2. Description of the Related Art Known documents describing the prior art according to the present invention include, for example, Japanese Utility Model Laid-Open No. 1-173749, Japanese Utility Model Laid-Open No. 1-172062, Japanese Utility Model Laid-open No. 2-41258, and Japanese Patent Laid-Open No. 1-216371. There is a gazette. In these publications, a guide roller is brought into contact with an outer peripheral surface of a photoconductor as a means for positioning an optical writing unit (a distance between the photoconductor and the optical writing unit) with respect to a drum-shaped photoconductor. And a pressing member that rolls and presses the optical writing unit in the direction of the photoconductor. However, it can be used only with a drum-shaped photoconductor, and cannot be used with a bell-shaped photoconductor. In addition, since the guide roller is brought into direct contact with the surface of the photoreceptor, if toner enters between the guide roller and the photoreceptor or adheres to the rotation shaft of the guide roller, the rotation of the guide roller is not performed smoothly and the image is not obtained. Causes disturbance. Further, Japanese Unexamined Utility Model Publication No. 2-35143 and Japanese Unexamined Utility Model Publication No. 1-157354 allow a holding member (optical writing unit) to be slidable in the optical axis direction by a pressing member and an (eccentric cam). The distance between the photosensitive member and the imaging element is adjusted. However, the position adjusting mechanism is complicated and large in space, and is not suitable for a small-sized and low-cost device.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure, capable of positioning an optical writing unit, has high reproducibility of positioning, and is easy to attach and detach the optical writing unit. The purpose is to provide an inexpensive image forming apparatus.

[0004]

To achieve the above object, the present invention provides (1)
A photoreceptor unit rotatably supporting the photoreceptor, a charger for charging the surface of the photoreceptor, and an electrostatic latent image formed on the surface of the photoreceptor charged by the charger. An image forming apparatus comprising an optical writing unit and a developing unit for developing an electrostatic latent image to develop a latent image, wherein the upper part of the apparatus main body can be opened and closed by an upper cover. How to scan
Protruding members supported at both ends of the optical writing unit.
The knit has an axis projecting from both ends in the main scanning direction.
Is inserted through an elongated hole provided in the projecting member, and
The optical writing unit is slidably mounted in the direction of the photoconductor.
Knit further includes a positioning portion that determines the distance between the photosensitive member to the light writing unit, before Symbol photosensitive unit
The upper cover was closed by providing a reference portion facing the positioning portion of the optical writing unit, and interposing a pressing member for pressing the optical writing unit in the direction of the photoconductor between the optical writing unit and the upper cover. Sometimes, the optical writing unit is positioned with respect to the photoreceptor unit. Further, (2) a first positioning portion for determining the distance between the optical writing unit and the photoreceptor; And a second reference portion for determining the first and second reference portions is provided on the photoreceptor unit so as to face the first and second positioning portions, respectively. The optical writing unit is positioned with respect to the photoconductor unit when the cover is closed. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment of an image forming apparatus according to the present invention. In FIG.
2 ₁ to 2 ₃ is a plurality of rollers, the photoreceptor 3, 4 a charger, a solid scanning optical writing unit (print head), the developing unit 6 5, the developing sleeve 7, 8 denotes a paper feed unit, 9 Is a recording paper, 10 is a paper feed roller, 11 is a turn guide, 12 is a transport roller, 13 and 14 are guide plates,
15 conveying path, the conveying rollers 16, 17 a transfer charger, 18 sensor unit, 19 guide, 20 is a fixing unit, 20 ₁ fixing roller, 20 ₂ pressure roller, 21 paper discharge rollers, 22, 23 is a paper discharge unit, 24 is a cleaning unit, 25 is a blade, 26 is a collection roller, 27 is an upper cover, 28, 34, and 36 are fulcrums, 30 is a protective member,
1 is a rib, 32 is a guide part, 33 is an operation panel, and 35 is a guide member.

[0006] substantially in the center of the apparatus main body 1, a plurality of rollers 2 _1, 2 ₂ and 2 _{3-belt-shaped} photosensitive member 3 which is rotated in the clockwise direction is supported by is provided. That is, at least 2 of the plurality of rollers 2 ₁ , 2 ₂ and 2 ₃
It is configured such that a straight line connecting the rotation axes of the books is not substantially horizontal. Specifically, the roller 2 ₁ and 2 _2, roller 2 ₂ and 2 ₃ or roller 2 ₃ 2 ₁ of a straight line connecting the rotational axis of the at least one set of rollers is configured so as not to substantially horizontal, its diagonal By sequentially arranging process components according to the electrophotographic process around the arranged photoreceptor 3, it is possible to reduce the size of the apparatus, in other words, to increase the above-described functional density. Hereinafter, process components according to an electrophotographic process provided around the photoconductor 3 will be described.

First, a charging charger 4 for uniformly charging the surface of the photoconductor 3 is provided. Next, a solid-scanning optical writing unit (also referred to as a print head) 5 for irradiating writing light for forming an electrostatic latent image on the surface of the charged photoconductor 3 is provided. The solid scanning type optical writing unit 5 includes a phosphor dot array, an LED array,
A C shutter array, an EL dot array, a plasma dot array, or the like is used. The guide plate 13 is disposed in contact with the back surface of the photoconductor 3 with respect to the solid-scanning optical writing unit 5 to maintain the relative position between the solid-scanning optical writing unit 5 and the photoconductor 3. Surface treatment such as Teflon coating is applied to prevent damage. Next, a developing unit 6 for developing the electrostatic latent image to make it visible is provided. The developing unit 6 includes a developing sleeve 7 and the like.

On the other hand, a paper feed unit 8 is mounted in the lower portion of the apparatus main body 1, and the recording paper 9 is separated and fed one by one by a paper feed roller 10. Recording paper 9 fed
Is transported by the pair of transport rollers 12 via the turn guide 11, and further passes through the transport path 15 formed by the guide portion 32 having the ribs 31 and the guide plate 14, and passes through the sensor portion 18.

That is, the conveyance path of the recording paper 9 is configured such that the recording paper 9 is turned by 180 ° or more, and the recording paper 9 is folded without providing a fold in the recording paper 9. This makes it possible to reduce the size of the device, in other words, to increase the functional density described above. The recording paper 9 that has passed through the sensor unit 18 is conveyed toward the photoconductor 3 by a pair of subsequent conveyance rollers 16 (this can also function as a so-called registration roller), and the operation of the transfer charger 17 is performed. Undergoes image transfer. The sensor unit 18 basically generates a different electric signal depending on the presence or absence of the recording paper 9, but by using this electric signal, it is possible to detect the leading end of the recording paper 9. The controller (not shown) determines the exposure timing of the solid-state scanning optical writing unit 5 based on the time when the leading edge of the recording paper 9 is detected.

That is, it is necessary that the leading end of the recording paper 9 and the leading end of the image area on the photosensitive member 3 be positioned at the transfer charger 17 at the same timing. Using a known time from when the leading end portion passes through the sensor portion 18 to when the leading end portion contacts the photosensitive member 3 and is located at the transfer charger 17 portion, based on the time when the leading end portion of the recording paper 9 is detected, The point at which an image should be formed on the photoconductor 3 is determined. The recording paper 9 after the transfer is separated from the photoconductor 3 by the curvature of the photoconductor 3 and the weight of the recording paper 9, and is sent to the fixing unit 20 via the guide 19. In the fixing unit 20, the fixing roller 20 ₁
And the recording sheet 9 between the pressure roller 20 ₂ is conveyed sandwiched, and is further discharged onto the sheet discharge roller 21 discharge section formed in the upper portion of the conveyed device main body side 22 or 23 .

On the other hand, the residual toner on the surface of the photoreceptor 3 after the transfer is cleaned and removed by the blade 25 of the cleaning unit 24 and collected by a collecting roller 26 into a collecting container (not shown). Thereafter, the photoconductor 3 is again subjected to charging by the charging charger 4. At the time of replacement of each unit or processing of paper jam, the upper cover 27 is pivotally opened upward about the fulcrum 28 as shown by a virtual line (two-dot chain line) in the figure. When the upper cover 27 is opened, the charging charger 4, the fixed scanning type optical writing unit 5, and the developing unit 6 also follow as shown by the imaginary line, and the periphery of the photoconductor 3 is largely opened.

When performing manual paper feeding instead of paper feeding from the paper feeding unit 8, the operation panel 33 is rotated about a fulcrum 34 as shown by a virtual line in the drawing. That is, operation panel 3
Since the guide member 35 rotates in a phantom line around the fulcrum 36 in conjunction with the movement of 3, after the desired recording paper is inserted along the guide member 35 until it hits the transport roller 12, the operation panel 33 When the user presses the print button (not shown), an image forming operation is started, and an image is formed on a recording sheet by the above-described process and the sheet is discharged.

FIG. 2 is an enlarged side view of the periphery of the optical writing unit and the photoreceptor unit, and FIG. 3 is an enlarged view of a portion A of FIG. 2, wherein 50 is a photoreceptor unit, 51 is a protruding portion, and 52 is a shaft. ,
53 is a long hole, 54 is a notch, 55 is a projection, 56 is a projection, 57 is a spring, 58 is a first positioning part, 59 is a first reference part, and 60 is a quenchin clamp.

A projecting portion 51 projects downward from the upper cover 27, and the optical writing unit 5 is supported by the projecting portions 51 on both sides in the longitudinal direction. At this time, the optical writing unit 5 is supported by the protruding portion 51 so that the optical writing unit 5 can slide vertically in the direction of the photoconductor 3 and the optical writing unit 5 does not fall down. More specifically, the optical writing unit 5 is provided with a shaft 52 protruding from each side surface thereof, and the protruding portion 51 is provided with a long hole 53, and the shaft 52 slides in the long hole 53. Supported where possible. However, in this state, the optical writing unit 5 rotates, so that the optical writing unit 5 is formed with the projections 55 optically positioned (that is, provided with the positioning portions) on both side surfaces thereof. Have been. A notch 54 is formed in the protrusion 51 so that the protrusion 55 can slide (even if there is play). By doing so, the optical writing unit 5
Can be slid in the direction of the photoconductor 3. Further, the upper cover 27 is pressed so as to press the optical writing unit 5 with an appropriate force.
, And a spring 57 is attached so as to protrude from the optical writing unit 5. This pressing means is also provided on both sides in the longitudinal direction of the optical writing unit 5.

As described above, the projection 55 of the optical writing unit 5 is provided with the first positioning portion 58 from which the optical position is set to determine the distance from the photoconductor 3. The body unit 50 is provided in parallel with the photoconductor 3 with a first reference portion 59 extending from the photoconductor 3 in order to determine the distance from the optical writing unit 5.
Therefore, when the first positioning portion 58 and the first reference portion 59 come into contact with each other, the interval between the optical writing unit 5 and the photoconductor 3 can be determined at the set position.

Further, as shown in FIG.
The means for maintaining the relative position between the photosensitive member 3 and the
In the case of (1), there is no problem even if the optical writing unit 5 slightly moves in the direction B with respect to the photoconductor unit 50. However, as shown in FIG. 4, when the opposing roller 61 or the photoconductor 3 is in a drum shape, If the focal position in the B direction deviates, the exposure light will be blurred, so it is necessary to position the B direction as well. Therefore, the second positioning portion 62 whose optical position is set so that the optical axis is directed to the center of the opposing roller 61 or the like on the projection 55 of the optical writing unit 5, and the second reference perpendicular to the first reference 59. The second positioning portion 62 and the second reference portion 63 are brought into contact with each other to perform positioning in the B direction. Note that the positioning portion and the reference portion are located on the upper cover 27.
By closing the upper cover 27, the upper cover 27 is positioned.
When is opened, the optical writing unit 5 is
7, the positioning portion and the reference portion are separated from each other.

FIGS. 5A to 5C and FIGS. 6D to 6K.
FIG. 7 is a detailed view of parts of the upper cover, and FIGS. 7A to 7C are detailed views of parts of the photoreceptor unit (upper housing). FIG.
5A is a plan view, FIG. 5B is an EE cross-sectional view, and FIG.
6D is an FF sectional view, FIG. 6D is an LL side view, FIG. 6E is an HH sectional view, FIG. 6F is an II sectional view, and FIG.
FIG. 6 (h) is a BB sectional view, FIG. 6 (i) is a GG sectional view, FIG. 6 (j) is a JJ sectional view, and FIG. 6 (k) is a KK sectional view. 7A is a plan view, FIG. 7B is a side view,
FIG. 7C is a CC side view.

[0018]

As apparent from the above description, the present invention has the following effects. The optical writing unit is supported on the upper cover so that it can slide in the direction of the photoconductor, and the optically positioned positioning part and the reference part are in contact with each other. Can be put out. In addition, since the optical writing unit is floated on the upper cover, the structure is easy to attach / detach and remove stains on the exposed surface. Furthermore, the writing unit length
Pressing positions (spring positions) near both ends in the hand direction
And press the writing unit toward the photoconductor.
To the writing unit generated when pressing and fixing
Unnecessary stress can be reduced as much as possible,
Prevents occurrence and reduces optical performance due to pressing of writing unit
Can be prevented. When it is necessary to determine the exposure position, it is only necessary to provide the second positioning portion and the reference portion. Therefore, since an adjusting mechanism is not required, the configuration can be made compact.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is an enlarged side view of the periphery of an optical writing unit and a photoconductor unit.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 is a diagram illustrating a case where an opposing roller is used as a unit for holding a relative position between the optical writing unit and the photosensitive member.

FIG. 5 is a detailed view of parts of an upper cover.

FIG. 6 is a detailed view of parts of an upper cover.

FIG. 7 is a detailed view of parts of the photoconductor unit.

[Explanation of symbols]

1 the apparatus body 2 ₁ to 2 ₃ more rollers 3 photoconductor 4 charged charger 5 solid scanning optical writing unit (print head) 6 developing unit 7 developing sleeve 11 turn guide 12 transport rollers 13, 14 guide plate 15 conveying path 16 conveying Roller 17 Transfer charger 18 Sensor unit 19 Guide 20 Fixing unit 20 ₁ Fixing roller 20 ₂ Pressure roller 21 Discharge roller 22, 23 Discharge unit 24 Cleaning unit 25 Blade 26 Collection roller 27 Upper cover 28, 34, 36 Support point 32 Guide Department

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-18367 (JP, A) JP-A-63-135265 (JP, A) JP-A 1-267663 (JP, A) JP-A-1- 237564 (JP, A) JP-A-63-43166 (JP, A) JP-A-63-66847 (JP, U) JP-A-61-206962 (JP, U) JP-A-61-176522 (JP, U) Japanese Utility Model 2-10548 (JP, U) Japanese Utility Model 1-71737 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21 / 18 G03G 15/04

Claims (2)

(57) [Claims] A photoconductor unit rotatably supporting the photoconductor, a charging charger for charging the surface of the photoconductor, and an electrostatic latent surface on the surface of the photoconductor charged by the charging charger. In an image forming apparatus comprising an optical writing unit for forming an image, and a developing unit for developing an electrostatic latent image to develop the image, wherein the upper part of the apparatus main body can be opened and closed by an upper cover , the upper cover is Optical writing uni
A projecting member that supports the unit at both ends in the main scanning direction,
The optical writing unit projects from both ends in the main scanning direction.
A shaft, and the shaft is provided in an elongated hole provided in the protruding member.
Inserted and slidably mounted in the direction of the photoconductor
Is, light writing unit further includes a positioning portion that determines the distance between the photosensitive member to the light writing unit, before <br/> Symbol reference opposite the positioning portion of the optical writing unit to the photosensitive member unit The optical writing unit is positioned with respect to the photoconductor unit when the upper cover is closed by interposing a pressing member for pressing the optical writing unit in the direction of the photoconductor between the optical writing unit and the upper cover. An image forming apparatus, comprising: 2. The optical writing unit according to claim 1, further comprising: a first positioning unit for determining an interval between the photoconductor and a second positioning unit for determining an exposure position on the photoconductor. A first reference portion and a second reference portion provided on the photoconductor unit so as to face the photoconductor unit, and the optical writing unit is positioned with respect to the photoconductor unit when the upper cover is closed. The image forming apparatus according to claim 1.