Image forming apparatus component positioning mechanism

An image forming apparatus includes: an image carrier; a latent-image forming device; a developing device; a latent-image forming device contacting/separating mechanism; and a developing device contacting/separating mechanism, and the latent-image forming device contacting/separating mechanism allows the latent-image forming device to be movable to the latent-image forming device contacting position in a state where the developing device is moved to the developing device contacting position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2007-214804 filed on Aug. 21, 2007.

BACKGROUND

Technical Field

SUMMARY

According to an aspect of the invention, there is provided an image forming apparatus comprising: an image carrier; a latent-image forming device that forms a latent image in a surface of the image carrier; a developing device that develops the latent image of the surface of the image carrier; a latent-image forming device contacting/separating mechanism that moves the latent-image forming device between a latent-image forming device contacting position where a part of the latent-image forming device is positioned with being contacted with a part of the image carrier, and a latent-image forming device separating position where the latent-image forming device is separated from the image carrier; and a developing device contacting/separating mechanism that moves the developing device between a developing device contacting position where a part of the developing device is positioned with being contacted with a part of the image carrier, and a developing device separating position where the developing device is separated from the image carrier, wherein the latent-image forming device contacting/separating mechanism performs at least one of (i) and (ii), wherein (i) is that the latent-image forming device contacting/separating mechanism allows the latent-image forming device to be movable to the latent-image forming device contacting position in a state where the developing device is moved to the developing device contacting position, and (ii) is that the latent-image forming device contacting/separating mechanism restricts the latent-image forming device from being moved to the latent-image forming device contacting position in a state where the developing device is moved to the developing device separating position.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

DETAILED DESCRIPTION

Next, examples which are exemplary embodiments of the invention will be described with reference to the accompanying drawings. However, the invention is not restricted to the following examples.

In order to facilitate the understanding of the following description, the front and rear directions in the drawings are indicated as X-axis directions, the right and left directions are indicated as Y-axis directions, and the upper and lower directions are indicated as Z-axis directions. The directions or sides indicated by the arrows X, −X, Y, −Y, Z, and −Z are the front, rear, right, left, upper, and lower directions, or the front, rear, right, left, upper, and lower sides, respectively.

In the figures, the symbol in which “•” is written in “◯” indicates the arrow which is directed from the rear of the sheet to the front, and that in which “x” is written in “◯” indicates the arrow which is directed from the front of the sheet to the rear.

In the following description with reference to the drawings, illustrations of members other than those which are necessary in description are suitably omitted for the sake of easy understanding.

FIG. 1is a diagram illustrating the whole of an image forming apparatus of Example 1 of the invention.

Referring toFIG. 1, the image forming apparatus U comprises an automatic document conveying device U1, and an image forming apparatus body U2which supports the device, and which has a transparent document reading face PG in the upper end.

The automatic document conveying device U1has: a document feeding portion TG1in which plural documents Gi to be copied are housed in a stacked manner; and a document discharging portion TG2to which the documents Gi fed from the document feeding portion TG1and passed through a document reading position on the document reading face PG are discharged.

The image forming apparatus body U2has an operation portion UI through which the user inputs an operation command signal such as the start of an image forming operation, an exposing optical system A, etc.

Reflected light from a document which is conveyed on the document reading face PG by the automatic document conveying device U1, or that which is manually placed on the document reading face PG is passed through the exposing optical system A and converted by a solid-state imaging element CCD to electric signals of red R, green G, and blue B.

An image information converting portion IPS converts the electric signals of RGB to image information of black K, yellow Y, magenta M, and cyan C supplied from the solid-state imaging element CCD, temporarily stores the image information, and supplies the image information at a predetermined timing as image information for forming latent images, to a latent-image forming device driving circuit DL.

In the case where the document image is a single-color image or a so-called monochromatic image, only image information of black is supplied to the latent-image forming device driving circuit DL.

The latent-image forming device driving circuit DL has driving circuits (not shown) for the respective colors Y, M, C, and K, and supplies signals corresponding to the input image information at predetermined timings, to latent-image forming devices LHy, LHm, LHc, LHk which are disposed for the respective colors.

FIG. 2is an enlarged view illustrating main portions of the image forming apparatus of Example 1.

Visible-image forming devices Uy, Um, Uc, Uk which are placed in a middle portion in the gravitational direction of the image forming apparatus U form toner images of the colors of yellow Y, magenta M, cyan C, and black K, respectively.

Latent-image writing beams Ly, Lm, Lc, Lk of Y, M, C, and K emitted from laser diodes of the latent-image forming devices LHy to LHk impinge on rotary image carriers PRy, PRm, PRc, PRk, respectively. In Example 1, the latent-image forming devices LHy to LHk are configured by so-called LED arrays, respectively.

The image forming apparatus Uy for Y has the rotary image carrier PRy, a charging device CRy, the latent-image forming device LHy, a developing device Gy, a transferring device T1y, and an image-carrier cleaner CLy.

The visible-image forming devices Um, Uc, Uk are configured in a similar manner as the visible-image forming device Uy for Y.

Referring toFIGS. 1 and 2, the image carriers PRy, PRm, PRc, PRk are charged by the respective charging devices CRy, CRm, CRc, CRk, and, at image writing stations Q1y, Q1m, Q1c, Q1k, electrostatic latent images are then formed in their surfaces by the latent-image writing beams Ly, Lm, Lc, Lk. In developing regions Q2y, Q2m, Q2c, Q2k, the electrostatic latent images in the surfaces of the image carriers PRy, PRm, PRc, PRk are developed into toner images which are examples of visible images by developers held by developing rolls GRy, GRm, GRc, GRk which are examples of developer carriers of the developing devices Gy, Gm, Gc, Gk.

The developed toner images are conveyed to primary transferring regions Q3y, Q3m, Q3c, Q3kwhich are contacted with an intermediate transfer belt B that is an example of an intermediate transferring member. At a predetermined timing, a power source circuit E which is controlled by a controller C applies a primary transfer voltage in which the polarity is opposite to the charging polarity of the toner, to primary transferring devices T1y, T1m, T1c, T1kplaced on the rear face side of the intermediate transfer belt B in the primary transferring regions Q3y, Q3m, Q3c, Q3k.

The toner images on the image carriers PRy to PRk are primarily transferred to the intermediate transfer belt B by the primary transferring devices T1y, T1m, T1c, T1k. Residual toners on the surfaces of the image carriers PRy, PRm, PRc, PRk after the primary transfer are cleaned by the image-carrier cleaners CLy, CLm, CLc, CLk. The surfaces of the image carriers PRy, PRm, PRc, PRk which have been cleaned are again charged by the charging devices CRy, CRm, CRc, CRk.

A belt module BM which is an example of an intermediate transferring device, and which is vertically movable and forward extractable is placed above the image carriers PRy to PRk. The belt module BM has: the intermediate transfer belt B which is an example of an intermediate-transferring member; a belt supporting roll Rd+Rt+Rw+Rf+T2awhich is an intermediate-transferring member support member, and which includes a belt driving roll Rd that is an example of an intermediate-transferring member driving member, a tension roll Rt that is an example of an intermediate-transferring member stretching member, a walking roll Rw that is an example of a meandering preventing member, an idler roll Rf that is an example of a driven member, and a backup roll T2athat is an example of a secondary-transfer region opposing member; and the primary transferring devices T1y, T1m, T1c, T1k. The intermediate transfer belt B is supported in a rotary movable manner by the belt supporting roll Rd+Rt+Rw+Rf+T2a.

A secondary transfer roll T2bwhich is an example of a secondary transfer member is placed while opposing to the surface of the intermediate transfer belt B contacted with the backup roll T2a. A secondary transferring device T2is configured by the rolls T2a, T2b. A secondary transferring region Q4is formed in a region where the secondary transferring device T2band the intermediate transfer belt B are opposed to each other.

The single or multi-color toner images which are sequentially stackingly transferred onto the intermediate transfer belt B by the transferring devices T1y, T1m, T1c, T1kin the primary transferring regions Q3y, Q3m, Q3c, Q3kare conveyed to the secondary transferring region Q4.

Three pairs of right and left guide rails GR, GR which are examples of a guiding member for retractably supporting sheet feeding trays TR1to TR3that are examples of a sheet feeding container, so as to be extractable and retractable in the front and rear directions (X-axis direction) are disposed below the visible-image forming devices Uy to Uk. Recording sheets S which are examples of media housed in the sheet feeding trays TR1to TR3are taken out by a pickup roll Rp which is an example of a medium taking out member, and separated one by one by a separating roll Rs which is an example of a medium separating member. Then, the recording sheet is conveyed by plural conveying rolls Ra which are examples of a medium conveying member, along a sheet conveying path SH which is an example a medium conveying path, and sent to a registration roll Rr which is an example a transfer-region conveyance timing adjusting member, and which is disposed on the upstream side of the secondary transferring region Q4in the sheet conveying direction. A sheet conveying device SH+Ra+Rr is configured by the sheet conveying path SH, the sheet conveying rolls Ra, the registration roll Rr, etc.

The registration roll Rr conveys the recording sheet S to the secondary transferring region Q4in timing with the conveyance of the toner image formed on the intermediate transfer belt B to the secondary transferring region Q4. When the recording sheet S is passed through the secondary transferring region Q4, the backup roll T2ais grounded, and the power source circuit E which is controlled by the controller C applies a secondary transfer voltage which is opposite to the charging polarity of the toner, to the secondary transferring device T2bat a predetermined timing. At this time, the color toner image on the intermediate transfer belt B is transferred to the recording sheet S by the secondary transferring device T2.

After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLb which is an example of an intermediate-transferring member cleaner.

The recording sheet S onto which the toner image has been secondarily transferred is conveyed to a fixing region Q5which is a press contact region between a heating roll Fh that is an example of a heating fixing member of a fixing device F, and a pressuring roll Fp that is an example of a pressuring fixing member, and subjected to heating fixation when passed through the fixing region. The recording sheet S which has undergone heating fixation is discharged to a discharge tray TRh which is an example of a medium discharging portion, from a discharging roller Rh which is an example of a medium discharging member.

A release agent which improves the property of releasing of the recording sheet S from the heating roll is applied to the surface of the heating roll Fh by a release-agent applying device Fa.

Developer cartridges Ky, Km, Kc, Kk which are examples of developer replenishment containers respectively housing developers of yellow Y, magenta M, cyan C, and black K are arranged above the belt module BM. The developers housed in the developer cartridges Ky, Km, Kc, Kk are replenished to the developing devices Gy, Gm, Gc, Gk in accordance with consumptions of the developers of the developing devices Gy, Gm, Gc, Gk, through developer replenishment paths which are not shown. In Example 1, each developer is configured by a two-component developer containing a magnetic carrier, and a toner to which an external additive is added.

Referring toFIG. 1, the image forming apparatus U has an upper frame UF and a lower frame LF. The upper frame UF supports the visible-image forming devices Uy to Uk and the components which are placed above the visible-image forming devices Uy to Uk, i.e., the belt module BM, etc.

The lower frame LF supports the guide rails GR supporting the sheet feeding trays TR1to TR3, the sheet feeding members which feed sheets from the trays TR1to TR3, i.e., the pickup roll Rp, the separating roll Rs, the sheet conveying rolls Ra, etc.

(Description of Members of Visible-Image Forming Devices)

FIG. 3is a view illustrating relationships of the image carrier, the latent-image forming device, and the developing device in the image forming apparatus of Example 1 of the inventionFIG. 3Ais a diagram of a state where the developing device is moved to a developing device contacting position, and the latent-image forming device is moved to a latent-image forming device contacting position, andFIG. 3Bis a diagram of a state where the developing device is moved to a developing device separating position, and the latent-image forming device is moved to a latent-image forming device separating position.

Next, the developing devices Gy, Gm, Gc, Gk and latent-image forming devices LHy, LHm, LHc, LHk which constitute the visible-image forming devices Uy, Um, Uc, Uk in Example 1 of the invention will be described. Since the members for the respective colors are configured in the same manner, only those for Y color will be described, and detailed description of the members for the other colors will be omitted.

(Description of Developing Device)

Referring toFIG. 3, the developing device Gy in Example 1 has a developing container1in which a developer is housed. A pair of stirring conveying members2,3which convey the developer in the container while stirring the developer are rotatably supported in the developing container1. A developer holding member4which holds the developer stirred by the stirring conveying members2,3to the surface, and which conveys the developer to the developing region Q2ythat is a region opposed to the image carrier PRy is rotatably supported in the developing container1.

Referring toFIG. 3, the developing container1is swingably supported about a swing shaft6on a frame member which is not shown, or a so-called frame of a developing unit. One end of a developing device urging member7which always urges the developer holding member4toward the image carrier PRy is supported on the outer wall of the developing container1which is opposite to the image carrier PRy with respect to the swing shaft6. Therefore, the developer holding member4receives a force in a direction along which the member is always pressed toward the image carrier PRy. The distance between the developer holding member4and the image carrier PRy is held to a predetermined value by developing-region butting portions (not shown) or so-called tracking portions which are placed in the both end portions of the developer holding member4, and which function as developing device positioning portions in the developer holding member4. In a normal state, namely, the developing device Gy is held to the developing device contacting position shown inFIG. 3A. When an external force causing the developing device Gy to rotate in the direction along which it is separated from the image carrier PRy is applied, the developing device Gy is separated from the image carrier PRy against the force of the developing device urging member7. Namely, a developing device contacting/separating mechanism (6+7) in Example 1 is configured by the swing shaft6and the developing device urging member7.

An interlocking contacted member8which extends toward the latent-image forming device LHy is supported on the outer wall of the developing container1on the side of the latent-image forming device LHy. Furthermore, a leakage preventing member9which is in contact with the surface of the image carrier PRy to prevent the developer from downward leaking is supported below the developer holding member4of the developing container1.

FIG. 4is a perspective diagram illustrating the latent-image forming device in Example 1,FIG. 4Ais a view illustrating a state where the latent-image forming device is moved to the latent-image forming device contacting position, andFIG. 4Bis a view illustrating a state where the latent-image forming device is moved to the latent-image forming device separating position.

FIG. 5is a view illustrating an outer frame member of the latent-image forming device in Example 1,FIG. 5Ais a plan view, andFIG. 5Bis a side view.

Referring toFIG. 4, the latent-image forming device LHy in Example 1 has an outer frame member11which is fixed and supported on the image forming apparatus body U2by means of screws. Referring toFIG. 5, the outer frame member11has: a bottom wall11awhich extends in the front and rear directions that coincide with the axial direction of the image carrier PRy; and left and right side walls11b,11cwhich upward extend from the left and right ends of the bottom wall11a, respectively. A pair of urging member end supporting portions11dhaving a hole-like shape are formed in front and rear end portions of the bottom wall11a.

Referring toFIGS. 4 and 5, a fixed portion11ewhich downward extends is formed on the lower faces of front end portions of the left and right side walls11b,11c, and screwed to the image forming apparatus body U2through holes11e1formed in the fixed portion11e. A pair of front and rear interlocking contacting member outer passing portions11fare formed in the right side wall11c. Each of the interlocking contacting member outer passing portions11fin Example 1 is configured by an arcuate oblong hole. A pair of front and rear swing shaft supporting portions11gare formed above the interlocking contacting member outer passing portions11f. A pair of left and right operating member supporting portions11hare formed in front end portions of the left and right side walls11b,11c. Each of the operating member supporting portions11hin Example 1 is configured by a through hole.

FIG. 6is a view illustrating the positional relationship of the latent-image forming device and the image carrier in Example 1,FIG. 6Ais a view illustrating a state where the latent-image forming device is moved to the latent-image forming device contacting position, andFIG. 6Bis a view illustrating a state where the latent-image forming device is moved to the latent-image forming device separating position.

FIG. 7is a view illustrating main portions of a contacting/separating mechanism of the latent-image forming device in Example 1 in a state where illustration of a part of the outer frame member is omitted from the state shown inFIG. 4,FIG. 7Ais a view illustrating a state where the device is moved to the latent-image forming device contacting position, andFIG. 7Bis a view illustrating a state where the device is moved to the latent-image forming device separating position.

Referring toFIGS. 4 and 7, an operating member12is supported by the operating member supporting portions11hof the outer frame member11so as to be swingable about a swing shaft member12aof the operating member12. The operating member12has a grip portion12bwhich is to be operated with being gripped by the user, and supported so that, when the grip portion12bis gripped and operated, the operating member12is movable between a normal position where the member is upward swung as shown inFIGS. 4A,6A, and7A, and an insertion/extraction enabled position where the member is forward swung as shown inFIGS. 4B,6B, and7B. In Example 1, as shown inFIG. 6A, the operating member12is configured so that, at the normal position, the grip portion12bis placed in front of the image carrier PRy in the axial direction, and the axial movement of the image carrier PRy, i.e., attachment and detachment of the image carrier PRy with respect to the image forming apparatus body U2are restricted.

FIG. 8is a view illustrating an operation coupling member of the latent-image forming device in Example 1,FIG. 8Ais a perspective view, andFIG. 8Bis a side view.

Referring toFIG. 4, the operation coupling member13which is contacted with the swing shaft member12ais placed between the right side wall11cof the outer frame member11and the operating member12. Referring toFIGS. 7 and 8, the operation coupling member13is configured by a coupling arm which extends in the front and rear directions, and a swung supporting portion13awhich is swingably supported by the operating member12is formed in a front end portion. Referring toFIG. 7, a depressed shaft coupling recess13bis formed in a rear end portion of the operation coupling member13. A dead center13cis set on an extension of a phantom line which connects the arc enter of the arcuate portion of the shaft coupling recess13bwith the center of the swung supporting portion13a. As shown inFIGS. 6 and 7, the dead center is set so that, on the way of movement of the operating member12between the normal position and the insertion/extraction enabled position, the swing shaft member12aof the operating member12passes through the dead center13c, i.e., the position where the arc enter of the arcuate portion of the shaft coupling recess13b, the center of the swung supporting portion13a, and that of the swing shaft member12aare on a straight line.

FIG. 9is a view illustrating a moving member of the latent-image forming device in Example 1,FIG. 9Ais a perspective view, andFIG. 9Bis a side view.

Referring toFIGS. 7 and 9, the moving member14is placed on the side of the rear end of the operation coupling member13. The moving member14is accommodated in the outer frame member11, and supported so as to be movable in the front and rear directions. In a front end portion of the moving member14, a shaft supporting portion14ais formed correspondingly with the shaft coupling recess13bof the operation coupling member13. A coupling shaft16shown inFIG. 7is supported by the shaft supporting portion14a, and fitted into the shaft coupling recess13b, thereby coupling the members with each other.

Referring toFIGS. 7 and 9, a pair of front and rear interlocking contacting member inner passing portions14brespectively configured by rectangular holes are formed correspondingly with the interlocking contacting member outer passing portions11fof the outer frame member11. Above the interlocking contacting member inner passing portions14b, a pair of front and rear direction changing swing shaft passing portions14crespectively configured by oblong holes which extend in the front and rear directions are formed correspondingly with the swing shaft supporting portions11g.

FIG. 10is an enlarged view of main portions of an interlocking contacting member of the latent-image forming device in Example 1.

FIG. 11is a view illustrating a movement direction changing member of the latent-image forming device in Example 1,FIG. 11Ais a perspective view, andFIG. 11Bis a side view.

Referring toFIG. 7, inside the moving member14, a pair of front and rear movement direction changing members17are placed correspondingly with the direction changing swing shaft passing portions14c. In each of the movement direction changing members17, a direction changing swing shaft supporting portion17ais formed in an upper rear portion, and swingably supported by a direction changing swing shaft18which is passed through the direction changing swing shaft passing portion14cconfigured by the oblong hole, and which is supported by the swing shaft supporting portion11gof the outer frame member11. Namely, the movement direction changing member17is supported so as to be swingable with respect to the outer frame member11with setting the direction changing swing shaft18as the swing center. In Example 1, the direction changing swing shafts18are passed through the direction changing swing shaft passing portions14cconfigured by the oblong holes, respectively. When the moving member14is relatively moved in the front or rear direction with respect to the outer frame member, therefore, the movement range of the moving member14is restricted by the direction changing swing shafts18and the direction changing swing shaft passing portions14cas shown inFIG. 7.

Referring toFIGS. 10 and 11, an approaching/separating member coupling portion17bconfigured by an oblong hole which extends in the front and rear directions is formed in an upper front portion of each of the movement direction changing members17, and an interlocking contacting member supporting portion17cis formed in a lower rear portion of the movement direction changing member17. An urging member other end supporting portion17dis formed in an obliquely lower front side of the interlocking contacting member supporting portion17c. Referring toFIGS. 5 and 10, an urging spring19which is an example of a latent-image forming device urging member is attached between the urging member end supporting portion11dof the outer frame member11and the urging member other end supporting portion17d. The urging spring19exerts a force of always pulling the urging member other end supporting portion17dtoward the urging member end supporting portion11d. Namely, the movement direction changing member17is urged by the urging spring19in a direction along which the approaching/separating member coupling portion17bis upward swung about the direction changing swing shaft18.

FIG. 12is a view illustrating the interlocking contacting member disposed in the latent-image forming device in Example 1,FIG. 12Ais a perspective view, andFIG. 12Bis a side view.

Referring toFIGS. 7 and 10, the interlocking contacting member21is supported by the interlocking contacting member supporting portion17cof the movement direction changing member17. Referring toFIG. 12, the interlocking contacting member21has: a trapezoidal contacting member body21a; a supported portion21bwhich rearward extends from the rear face of the contacting member body21a; and an interlocking contacting portion21cwhich is formed integrally with an upper portion of the contacting member body21a. The supported portion21bis unswingably attached to the interlocking contacting member supporting portion17cin a state where the supported portion is passed through the interlocking contacting member outer passing portion11fof the outer frame member11and the interlocking contacting member inner passing portion14bof the moving member14. Therefore, the interlocking contacting member21is configured so as to be swingable integrally with the movement direction changing member17. In Example 1, the supported portion21bis configured in a rotation shaft-like shape, and has a diameter which is smaller than the diameters of the interlocking contacting member outer passing portion11fand the interlocking contacting member inner passing portion14b, so that the supported portion is passed with play therethrough.

When, in accordance with movement of the moving member14, the interlocking contacting member inner passing portion14bis contacted with the supported portion21b, and the moving member14is further moved, therefore, the approaching/separating member coupling portion17bof the movement direction changing member17is downward swung against the urging force of the urging spring19. In the normal state, the supported portion21bwhich is swung integrally with the movement direction changing member17forward pushes the interlocking contacting member inner passing portion14bby means of the urging force of the urging spring19, and hence the coupling shaft16is moved toward the shaft coupling recess13bso that the coupling between the operation coupling member13and the moving member14is held.

Referring toFIG. 3A, the contacting member body21aand the interlocking contacting portion21cof the interlocking contacting member21are placed outside the outer frame member11and on the side of the developing device Gy, and the interlocking contacting portion21cis placed below the interlocking contacted member8which extends from the developing device Gy.

The interlocking mechanism (8+21) in Example 1 is configured by the interlocking contacting member21and the interlocking contacted member8.

FIG. 13is a view illustrating an approaching/separating member of the latent-image forming device in Example 1,FIG. 13Ais a perspective viewFIG. 13Bis a side view, andFIG. 13Cis a plan view.

Referring toFIGS. 7 and 10, the approaching/separating member22is placed in the left of the movement direction changing member17. Referring toFIG. 13, the approaching/separating member22has an approaching/separating member body22awhich extends in the front and rear directions. In both front and rear end portions of the approaching/separating member body22a, coupling members22bwhich protrude toward the movement direction changing member17are supported at positions corresponding to the approaching/separating member coupling portions17bof the movement direction changing member17, respectively. Each of the coupling members22bis coupled to the approaching/separating member coupling portion17bwhich is configured by an oblong hole, in a loosely fitted state. When, in accordance with swing of the movement direction changing member17, a face of the approaching/separating member coupling portion17bis contacted with the coupling members22b, the approaching/separating member is pushed and moved vertically, i.e., in a direction along which the member is approached to or separated from the image carrier PRy. Light irradiating unit supporting portions22care formed in the upper faces of front and rear end portions of the approaching/separating member22. Escape holes22drespectively configured by oblong holes which extend in the vertical direction are formed in the right side of the light irradiating unit supporting portions22c. The escape holes22dallow the inner ends of the direction changing swing shafts18to escape.

FIG. 14is a view illustrating an image writing beam irradiating unit of the latent-image forming device in Example 1,FIG. 14Ais a perspective view, andFIG. 14Bis a side view.

Referring toFIGS. 7 and 10, the image writing beam irradiating unit23is supported by the light irradiating unit supporting portions22cof the approaching/separating member22. The image writing beam irradiating unit23has an irradiating unit body23awhich extends in the front and rear directions, and a light irradiating portion23bwhich is supported by the irradiating unit body23a, and which is placed opposedly to the image carrier PRy to emit a latent-image writing beam. In the light irradiating portion23bin Example 1, light sources which are used for forming a latent image in the surface of the image carrier PRy are arranged in the axial direction of the image carrier PRy, or namely in the main scanning direction. The light irradiating portion23bis configured by a so-called LED array.

FIG. 15is a view illustrating the positional relationship of the image carrier in Example 1 and the latent-image forming deviceFIG. 15Ais a top view, andFIG. 15Bis a side view.

Referring toFIGS. 6,14, and15, butting portions23cwhich upward protrude are formed in front and rear end portions of the irradiating unit body23a, and a pair of front and rear positioning portions23dwhich upward protrude are formed in the front and rear sides of the butting portions23c, respectively. Referring toFIG. 15, the butting portions23cis butted against bearing members24placed in both end portions of the image carrier PRy, to be vertically positioned. Referring toFIG. 15, when the latent-image forming device LHy is moved from the latent-image forming device separating position shown inFIG. 15Bto the latent-image forming device contacting position, the front positioning portion23dis passed through a positioned groove26bformed in a front positioned portion26asupported by a front end portion of a image carrier supporting frame member26, and the rear positioning portion23dis passed through a positioned oblong hole26dformed in a rear positioned portion26csupported by a rear end portion of the image carrier supporting frame member26, so that the latent-image forming device LHy is positioned in the front, rear, right, and left directions with respect to the image carrier PRy.

According to the configuration, at the latent-image forming device contacting position shown inFIG. 6A, the positional relationship of the light irradiating portion23band the surface of the image carrier PRy is held to a predetermined one, or correctly held so that the latent-image writing beam emitted from the light irradiating portion23bis focused on the surface of the image carrier PRy.

In the image forming apparatus U of Example 1, as shown inFIG. 3A, the image carrier PRy and the intermediate transfer belt B are contacted with each other on an extension of a phantom line27which connects the light irradiating portion23bwith the center of the image carrier PRy, and the primary transferring device T1yis placed at a position which is deviated toward the downstream side in the rotation direction of the intermediate transfer belt B.

The latent-image forming device contacting/separating mechanism (11to22) in Example 1 is configured by the outer frame member11, the operating member12, the operation coupling member13, the moving member14, the shafts16,18, the movement direction changing member17, the urging spring19, the supported portion21b, the approaching/separating member22, etc.

(Function of Example 1)

In the image forming apparatus U of Example 1 having the above-described configuration, as shown inFIGS. 3A and 6A, the moving member14is forward held through the movement direction changing member17by the urging force of the urging spring19in the state where the operating member12is moved to the normal position which is in the upper side. Therefore, the approaching/separating member22is held to the upper side, and the light irradiating portion23bof the image writing beam irradiating unit23is held in a state where a predetermined gap is formed between the portion and the image carrier PRy. Namely, the latent-image forming device LHy having the members12to23is held at the latent-image forming device contacting position to be set to a state where a latent image can be formed. The developing device Gy is held by the developing device urging member7, at the developing device contacting position where the device is approached and opposed with respect to the image carrier PRy while forming a predetermined gap. At this time, the interlocking contacting portion21cand the interlocking contacted member8are held in a state where the members are separated from each other, whereby vibrations produced by the rotation driving of the developer holding member4of the developing device Gy during an image forming operation are prevented from being transmitted to the latent-image forming device LHy, so that the latent image formation is correctly performed by the latent-image forming device LHy.

(Description of Operation of Separating Latent-Image Forming Device and Developing Device)

FIG. 16is a view illustrating a function in the case where the latent-image forming device and the developing device in Example 1 are to be separated from the image carrierFIG. 16Ais a view illustrating a state immediately after the movement of the operating member from the normal position to the insertion/extraction enabled position is startedFIG. 16Bis a view illustrating a state where the operating member is further moved from the state shown inFIG. 16Atoward the insertion/extraction enabled position, andFIG. 16Cis a view illustrating a state where the operating member is moved to the insertion/extraction enabled position.

In the case where the image carrier PRy is to be replaced because of abrasion, deterioration, failure, or the like, the operating member12is first swung because movement of the image carrier PRy is restricted by the operating member12. Referring toFIGS. 16A and 16B, the swing of the operating member12about the swing shaft member12acauses the operation coupling member13which is coupled to the operating member by the swung supporting portion13a, to be moved so as to be rearward pushed. The movement of the operation coupling member13causes the moving member14to be rearward moved through the coupling shaft16. In conjunction with the rearward movement of the moving member14, the interlocking contacting member inner passing portions14bof the moving member14is contacted with the supported portion21bof the interlocking contacting member21, and the supported portion21bis rearward moved. As a result, the movement direction changing member17to which the supported portion21bis coupled is swung about the direction changing swing shaft18against the urging force of the urging spring19.

At this time, as shown inFIGS. 16A and 16B, when the movement direction changing member17is swung and the play with respect to the coupling member22bof the approaching/separating member22is eliminated, the swinging operation is started, and the approaching/separating member coupling portion17bpushes down the coupling member22b. In accordance with the downward movement of the coupling member22b, the approaching/separating member22begins to be lowered, and starts movement in the direction along which the image writing beam irradiating unit23is separated from the image carrier PRy. By contrast, the interlocking contacting member21which is swung integrally in accordance with the swing of the movement direction changing member17is swung, and contacted with the interlocking contacted member8which has been separated therefrom.

Referring toFIGS. 16B and 16C, when the operating member12is further swung and the movement direction changing member17is swung, the interlocking contacting member21is contacted with and pushes up the interlocking contacted member8, and the developing device Gy begins to be moved in the direction along which the developing device is separated from the image carrier PRy about the swing shaft6against the urging force of the developing device urging member7.

Referring toFIGS. 3B,6B, and16C, when the operating member12is moved to the insertion/extraction enabled position, the latent-image forming device LHy is moved to the latent-image forming device separating position where the device is separated from the image carrier PRy, and the developing device Gy is moved to the developing device separating position where the device is separated from the image carrier PRy. In this state, the image carrier PRy can be extracted or inserted without causing the surface to be contacted with the latent-image forming device LHy or the developing device Gy. At his time, the swing shaft member12aof the operating member12exceeds the dead center13c. By the urging force of the urging spring19, therefore, the operation coupling member13is subjected to a forward pushing force, and the operating member12naturally receives a force of moving the member to the lower side of the operation coupling member13. Consequently, the operating member12is automatically held to the insertion/extraction enabled position unless the user applies a force to move the member toward the normal position.

(Description of Operation of Approaching Latent-Image Forming Device and Developing Device)

FIG. 17is a view illustrating a function in the case where the latent-image forming device and the developing device in Example 1 are to be approached to the image carrierFIG. 17Ais a view illustrating a state where the operating member is moved to the insertion/extraction enabled position,FIG. 17Bis a view illustrating a state immediately after the movement of the operating member from the state shown inFIG. 17Atoward the normal position is started, andFIG. 17Cis a view illustrating a state where the operating member is further moved from the state shown inFIG. 17Btoward the normal position.

Referring toFIG. 17, when the replacement of the image carrier PRy is completed, the operating member12is returned from the insertion/extraction enabled position to the normal position. At this time, when the operating member12begins the movement, the shaft coupling recess13bof the operation coupling member13is moved in the direction along which it is separated from the coupling shaft16, but the moving member14is forward moved by the urging force of the urging spring19, so that the coupling of the operation coupling member13and the moving member14is held. In accordance with the forward movement of the moving member14, the interlocking contacting member inner passing portions14bis contacted with the supported portion21bof the interlocking contacting member21, and the supported portion21bis forward moved. Therefore, also the movement direction changing member17to which the supported portion21bis coupled is swung about the direction changing swing shaft18.

At this time, the approaching/separating member coupling portion17bis fitted with play into the coupling member22bas shown inFIG. 17B, and hence the approaching/separating member22is not substantially moved unless the play is eliminated. By contrast, the interlocking contacting member21which is swung integrally in accordance with the swing of the movement direction changing member17is swung to begin to be moved in the direction along which it is separated from the interlocking contacted member8. When the interlocking contacting member21is moved in the direction along which it is separated from the interlocking contacted member8, the developing device Gy is caused by the urging force of the developing device urging member7of the developing device Gy to begin the movement in the direction along which the device is approached to the image carrier PRy about the swing shaft6.

Referring toFIG. 17C, when the operating member12is further swung and the movement direction changing member17is swung, the play between the approaching/separating member coupling portion17band the coupling member22bis eliminated, and the approaching/separating member coupling portion17bpushes up the coupling member22b. In accordance with the upward movement of the coupling member22b, the approaching/separating member22begins to be upward moved, and the image writing beam irradiating unit23begins to be moved in the direction along which it is approached to the image carrier PRy.

In accordance with the movement of the operating member12to the normal position, the developing device Gy and the latent-image forming device LHy are approached to the image carrier PRy. When the developing device Gy is caused by the developing device urging member7to be butted against the image carrier PRy, the developing container1is not further swung, and the pressing of the developing device urging member7against the interlocking contacting member21of the interlocking contacted member8is canceled. Namely, the developing device Gy is held to the state where the device is moved to the developing device contacting position. When the interlocking contacting member21and the interlocking contacted member8begin to be separated from each other, the butting portions23cof the latent-image forming device LHy are in the state before they are butted against the bearing members24.

Referring toFIG. 6B, when, after the developing device Gy is moved to the developing device contacting position, the operating member12is further swung to be moved to the normal position, the moving member14is forward moved by the urging force of the urging spring19, and the movement direction changing member17is further swung. In accordance with this, the interlocking contacting member21and the interlocking contacted member8are separated from each other. At this time, the butting portions23cof the latent-image forming device LHy are butted against the bearing members24, the latent-image forming device LHy is moved to the latent-image forming device contacting position, and the pair of front and rear positioning portions23dare fitted respectively into the positioned groove26band the positioned oblong hole26d, thereby performing the positioning.

FIG. 18is a view illustrating the positional relationship of the image carrier and the latent-image forming device in Example 1.

In Example 1, as indicated by the solid line inFIG. 18, the latent-image forming device LHy is butted in the state where the developing device Gy is butted against the image carrier PRy, and then the positioning is performed. In the case where, after the latent-image forming device LHy is positioned with respect to the image carrier PRy, the developing device Gy is butted against the image carrier PRy as indicated by the broken line inFIG. 18, failures such as that the position of the latent-image forming device LHy is deviated with respect to the image carrier PRy, and the gap between the latent-image forming device LHy and the image carrier PRy is changed to a small value, or the latent-image forming device LHy is inclined with respect to the image carrier PRy are prevented from occurring.

Example 1 is configured so that, when the image carrier PRy is to be replaced, the intermediate transfer belt B and the primary transferring device T1yare approached or separated with respect to the image carrier PRy, and moved independently from the approach and separation of the latent-image forming device LHy and the developing device Gy. In Example 1, in a state where the latent-image forming device LHy and the developing device Gy are moved to their respective contacting positions, the primary transferring device T1ycan be approached or separated with respect to the image carrier PRy. In Example 1, at this time, the primary transferring device T1yis placed at the position which is deviated toward the downstream side with respect to the contacting position of the image carrier PRy and the intermediate transfer belt B, so that, even when the primary transferring device T1yis approached to or separated from the image carrier PRy, the device is not pressed against the image carrier PRy. Even when, after the latent-image forming device LHy is positioned with respect to the image carrier PRy, the primary transferring device T1yis moved from a transferring device separating position to a transferring device contacting position, therefore, the position of the image carrier PRy is not changed, and the positional relationship of the latent-image forming device LHy and the image carrier PRy is held to a correct one.

Next, Example 2 of the invention will be described. In the description of Example 2, the components corresponding to those of Example 1 are denoted by the same reference numerals, and their detailed description will be omitted.

Example 2 is configured in the same manner as Example 1 except the following points.

FIG. 19is a view illustrating a latent-image forming device in Example 2,FIG. 19Ais a view corresponding toFIG. 6Aof Example 1, andFIG. 19Bis a view corresponding toFIG. 6Bof Example 1.

Referring toFIG. 19, in the latent-image forming device Lhy′ in Example 2, the interlocking contacting member21in Example 1 is omitted, and a movement coupling member31which corresponds to the supported portion21b, and through which the moving member14and the movement direction changing member17are coupled to each other is disposed. An interlocking contacting member21′ which is passed through the outer frame member11to protrude toward the developing device at a position deviated from the interlocking contacting member21in Example 1 in the front and rear directions is formed integrally with the moving member14. The interlocking contacting member21′ has a contacting portion21c′ which is more downward inclined as further rearward advancing.

In Example 2, in correspondence with the position of the interlocking contacting member21′, also the interlocking contacted member8is placed at a position which is rearward deviated as compared with the case of Example 1. In Example 2, as shown inFIG. 19A, the interlocking contacting member21′ and the interlocking contacted member8are held in a state where they are separated from each other in the front and rear directions, and, at the latent-image forming device separating position, the contacted member8is set so as to be held to a state where the member is pushed up by the inclined interlocking contacting member21′ as shown inFIG. 19B.

Although not illustrated, the interlocking contacting member outer passing portion11fis formed so as to extend in the front and rear directions along the movement direction of the moving member14as compared with the case of Example 1.

The interlocking mechanism in Example 2 is configured by the interlocking contacting member21′, the interlocking contacted member8, and the like. The latent-image forming device contacting/separating mechanism in Example 2 is configured by the movement coupling member31in addition to the moving member14, the movement direction changing member17, and the like.

(Function of Example 2)

In the image forming apparatus U of Example 2 having the above-described configuration, the moving member14is moved in the front and rear directions in interlocking with the swinging movement of the operating member12, the approaching/separating member22is moved up and down through the movement direction changing member17coupled to the moving member14by the movement coupling member31, and the image writing beam irradiating unit23is approached and separated with respect to the image carrier PRy.

When the operating member12is moved from the normal position to the insertion/extraction enabled position, the contacting portion21c′ is contacted with the interlocking contacted member8in accordance with the rearward movement of the moving member14, and the interlocking contacted member is pushed up by the inclined face, whereby the developing device Gy is moved to the developing device separating position. Also in Example 2, the gap between the interlocking contacting member21′ and the interlocking contacted member8at the latent-image forming device contacting position, the degree of the play between the approaching/separating member coupling portion17band the coupling member22b, and the like are set so that the developing device Gy can be butted before the latent-image forming device LHy is butted against the image carrier PRy.

Next, Example 3 of the invention will be described. In the description of Example 3, the components corresponding to those of Examples 1 and 2 are denoted by the same reference numerals, and their detailed description will be omitted.

Example 3 is configured in the same manner as Examples 1 and 2 except the following points.

FIG. 20is a diagram of the image forming apparatus of Example 3,FIG. 20Ais a diagram of a state where the components are at the transferring device contacting position and the latent-image forming device contacting position, andFIG. 20Bis a diagram of a state where the components are at the transferring device separating position and the latent-image forming device separating position.

FIG. 21is a view which illustrates the positional relationship of the image carrier, the latent-image forming device, and the primary transferring device in Example 3, and which corresponds toFIG. 3Ain Example 1.

Referring toFIG. 20, in the image forming apparatus U of Example 3, a transferring device approaching/separating operating member41is swingably supported by the front end wall of the frame member, or the frame of the belt module BM. The transferring device approaching/separating operating member41has a grip portion41awhich is to be gripped and operated by the user, and which extends in the right and left directions, and is configured so that, when the grip portion is gripped and the transferring device approaching/separating operating member41is operated, the member can be moved between the normal position shown inFIG. 20Aand the insertion/extraction enabled position shown inFIG. 20B. A bevel gear42is supported by a rotation shaft41aof the transferring device approaching/separating operating member41. The bevel gear42meshes with a driven bevel gear43placed in the belt module BM, and an approaching/separating gear44is supported coaxially with the driven bevel gear43.

One end portions46aof movement direction changing members46are coupled to the primary transferring devices T1yto T1k, respectively. The one end portions46aare configured so as to be guided in directions along which the portions are approached and separated with respect to the image carriers PRy to PRk, by guiding portions which are formed on the frame member of the belt module BM, and which are not shown. Each of the movement direction changing members46is formed into an inverted L-like shape. The other end portions46bof the movement direction changing members46are swingably coupled to a moving member47which is supported by the frame member of the belt module BM so as to be movable in the right and left directions. A gear portion47awhich meshes with the approaching/separating gear44is formed in a right end portion of the moving member47.

A transferring device approaching/separating mechanism in Example 3 is configured by the members denoted by the reference numerals41to47.

Referring toFIG. 20, the transferring device approaching/separating operating member41is placed at a position where insertion and extraction of the image carriers PRy to PRk are restricted at the normal position. The grip portion41aof the transferring device approaching/separating operating member41is placed at a position where the portion is interposed at the normal position between the operating members12of the latent-image forming devices LHy to LHk and the image carriers PRy to PRk.

Referring toFIG. 21, in Example 3, the primary transferring device T1yis placed on the extension of the phantom line27with respect to the image carrier PRy. In Example 1, the weight by which the primary transferring device T1yis pressed against the image carrier PRy is set to be smaller than that by which the latent-image forming device LHy is pressed against the image carrier PRy.

(Function of Example 3)

In the image forming apparatus U of Example 3 having the above-described configuration, normally, the primary transferring devices T1yto T1kare held in a state where the primary transferring devices are pressed by the transferring device approaching/separating mechanism against the image carriers PRy to PRk across the intermediate transfer belt B, and a tension is applied to the intermediate transfer belt B.

In the case where the image carriers PRy to PRk are to be replaced, first, the operating members12of the latent-image forming devices LHy to LHk are operated to separate the latent-image forming devices LHy to LHk and the developing devices Gy to Gk from the image carriers PRy to PRk. Next, when the transferring device approaching/separating operating member41is moved to the insertion/extraction enabled position, the primary transferring devices T1yto T1kare separated from the image carriers PRy to PRk by the gears42to44, the moving member47, and the movement direction changing members46, and the tension of the intermediate transfer belt B is reduced, so that the belt is separated from the image carriers PRy to PRk. In this state, the image carriers PRy to PRk can be replaced with new ones.

When the replacement of the image carriers PRy to PRk is ended, the primary transferring devices T1yto T1kare caused to be contacted with the image carriers PRy to PRk by the transferring device approaching/separating operating member41, and then the operating members12are operated to approach and butt the developing devices Gy to Gk and the latent-image forming devices LHy to LHk against the image carriers PRy to PRk in this sequence. In the state where the primary transferring devices T1yto T1kand the developing devices Gy to Gk are contacted with and butted against the image carriers PRy to PRk, namely, the latent-image forming devices LHy to LHk are butted against the image carriers PRy to PRk.

Next, Example 4 of the invention will be described. In the description of Example 4, the components corresponding to those of Example 1 are denoted by the same reference numerals, and their detailed description will be omitted.

Example 4 is configured in the same manner as Example 1 except the following points.

FIG. 22is a diagram of the image forming apparatus of Example 4,FIG. 22Ais a diagram of a state where the latent-image forming device is moved to the latent-image forming device contacting position and the developing device is moved to the developing device contacting position,FIG. 22Bis a diagram of a state where the latent-image forming device is moved to the latent-image forming device separating position and the developing device is moved to the developing device contacting position, andFIG. 22Cis a diagram of a state where the latent-image forming device is moved to the latent-image forming device separating position and the developing device is moved to the developing device separating position.

Referring toFIG. 22, in the image forming apparatus U of Example 4, the interlocking mechanism8+21in Example 1 is omitted, and a developing device operating member61which swings the developing device Gy about the swing shaft6is placed in front of the developing device Gy. The developing device operating member61has: an operating portion body61awhich is to be operated by the worker; and an insertion/extraction restricting portion61bwhich is inclined with respect to the operating portion body61a, and which restricts insertion and extraction of the image carrier PRy. The developing device operating member61in Example 4 is swingably supported by the frame member of the developing unit so as to be movable between the normal position shown inFIGS. 22A and 22B, and the separating position shown inFIG. 22C.

In Example 4, the developing device operating member61is set to substantially same positions in the front and rear directions with respect to the operating members12, and configured so that, even when the developing device operating member61is moved toward the separating position in the state shown inFIG. 22A, the member interferes with the operating member12and cannot be moved. At the separating position shown inFIG. 22C, similarly, the developing device operating member61enters the side of the operating member12. Even when it is tried to move the operating member12toward the normal position, therefore, the member interferes with the developing device operating member61and cannot be moved toward the developing position.

As shown inFIGS. 22A and 22B, at the normal position, the insertion/extraction restricting portion61bis placed in front of the image carrier PRy, insertion and extraction of the image carrier PRy are restricted, and, at the separating position shown inFIG. 22C, the insertion/extraction restricting portion61bis retracted from the front side of the image carrier PRy, and insertion and extraction of the image carrier PRy are allowed.

The developing device contacting/separating mechanism6+7+61in Example 4 is configured by the swing shaft6, the developing device urging member7, and the developing device operating member61.

(Function of Example 4)

In the image forming apparatus U of Example 4 having the above-described configuration, the image forming operation is performed in the state shown inFIG. 22A, and, when the image carrier PRy is to be replaced, first, the operating member12is operated to move the latent-image forming device LHy to the latent-image forming device separating position to attain the state shown inFIG. 22B. In the state shown inFIG. 22A, namely, the developing device operating member61cannot be operated without operating the operating member12, and, in the state where the latent-image forming device LHy is moved to the latent-image forming device contacting position, the developing device Gy cannot be moved to the developing device separating position.

In the state shown inFIG. 22B, insertion and extraction of the image carrier PRy are disabled by the insertion/extraction restricting portion61b, and insertion and extraction in the state where the developing device Gy is butted against the image carrier PRy are prevented from occurring.

When the developing device operating member61is swung in the state shown inFIG. 22B, the developing device Gy is separated from the image carrier PRy as shown inFIG. 22C, and the insertion/extraction restricting portion61bis retracted from the front face of the image carrier PRy, so that the state where insertion and extraction of the image carrier PRy are enabled is obtained.

In the state shown inFIG. 22C, the operating portion body61aof the developing device operating member61enters the side of the operating member12, and hence the operation of the operating member12is restricted. Namely, it is configured so that, in the state where the developing device Gy is moved to the developing device separating position, the latent-image forming device LHy cannot be moved to the latent-image forming device contacting position.

When the replacement of the image carrier PRy is ended, the developing device operating member61is operated, and then the operating member12is operated, whereby the developing device Gy and the latent-image forming device LHy are butted in this sequence against the image carrier PRy, and the positional accuracy of the latent-image forming device LHy is prevented from being lowered.

Although, in the above, the examples of the invention have been described in detail, the invention is not restricted to the examples. Various modifications are enabled within the scope of the spirit of the invention set forth in the claims. Modifications (H01) and (H02) of the invention will be exemplified.(H01) In the examples, a copier is exemplified as the image forming apparatus. The invention is not restricted to this. The image forming apparatus may be configured as a facsimile apparatus, a printer, or a multifunction machine having all or plural functions of such apparatuses. The image forming apparatus having the image carriers PRy to PRk, developing devices Gy to Gk, and latent-image forming devices LHy to LHk which are used for the four colors has been described. The invention is not restricted to this. The invention can be applied also to a monochrome image forming apparatus, and a rotary type image forming apparatus in which a single image carrier and a single latent-image forming device are used, and four developing devices are rotated to be sequentially opposed to the image carrier.(H02) Example 3 is configured so that the transferring device operating member41is placed in the inner side with respect to the operating members12of the latent-image forming devices LHy to LHk. Alternatively, the operating member may be placed in the outer side. In the alternative, after the latent-image forming devices LHy to LHk are moved to the latent-image forming device contacting position, the primary transferring devices T1yto T1kare pressed against the image carriers PRy to PRk. In Example 1, the weight by which the primary transferring device T1yis pressed against the image carrier PRy is set to be smaller than that by which the latent-image forming device LHy is pressed against the image carrier PRy. Therefore, the positional displacements of the image carriers PRy to PRk with respect to the latent-image forming devices LHy to LHk are suppressed to the minimum level.