JP4621063B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a color image forming apparatus that performs electrophotographic image formation, such as a copying machine, a printer, a facsimile machine, a plotter, or the like, or a multi-function machine including at least one of them.

Among image forming apparatuses in recent years, in image forming apparatuses that perform electrophotographic image formation, particularly color image forming apparatuses, such as copiers, printers, facsimiles, plotters, etc., or multi-function machines composed of at least one of these. Is formed by superposing four color toner images of yellow, magenta, cyan, and black on an intermediate transfer member such as an intermediate transfer belt, and transferring the toner image onto a sheet-like recording medium such as transfer paper. Perform full color printing.
In such a color image forming apparatus, a single image carrier on which a latent image is formed by exposure means, and a latent image on the image carrier that is arranged to face the image carrier, and a developer of at least two colors A first image forming unit composed of two developing means for developing the image, a single image carrier on which a latent image is formed by the exposure means, and a latent image on the image carrier arranged opposite to the image carrier. A toner image formed by a second image forming unit comprising two developing means for developing an image with a developer having a color different from the developer of the first image forming unit, and the first and second image forming units; An image forming apparatus comprising an intermediate transfer body that sequentially superimposes and transfers, and a transfer unit that transfers a color image formed on the intermediate transfer body to a sheet-like recording medium, that is, so-called hybrid type color image formation apparatus Known (e.g., see Patent Documents 1 and 2).

In the technique described in Japanese Patent Laid-Open No. 2001-1000048 (Patent Document 1), a color in which two image forming units in which two developing devices (developing devices) are arranged on the circumference of an image carrier (image carrier drum) are arranged. In the image forming apparatus, as countermeasures against color misregistration, (1) the circumference of the intermediate transfer belt is an integral multiple of the diameter of the image carrier, and (2) the circumference of the intermediate transfer belt is an integral multiple of the diameter of the intermediate transfer belt driving roller. (3) The pitch between the two image carriers is defined as an integral multiple of the diameter of the intermediate transfer belt drive roller.
Further, the technique described in Japanese Patent Laid-Open No. 10-177286 (Patent Document 2) has been proposed to solve the problem of increasing the size of the image forming apparatus and the problem that the number of printed sheets per unit time is small. Yes.

JP 2001-1000048 A Japanese Patent Laid-Open No. 10-177286

However, in both the technologies, when each developing unit is configured as a developing unit that is detachable from the apparatus main body, the number of parts is reduced, and a small (compact) and low cost image forming apparatus is provided. There is a problem to be improved.
Therefore, the present invention has been made in view of the above-described points, and has as its main object to provide an image forming apparatus that reduces the number of parts, is small (compact), and is low in cost.

In order to achieve the object mentioned above with solving the above problems, the invention of each 請 Motomeko adopts a means-configuration with the following characteristics.
According to a first aspect of the present invention, there is provided a drum-shaped single image carrier on which a latent image is formed by exposure means, and the latent image on the image carrier, which is arranged to face the image carrier, of at least two colors. A first image forming unit comprising two developing means for developing with a developer; a single image carrier on which a latent image is formed by an exposure means; and an image carrier disposed on and opposite to the image carrier. Formed by a first image forming unit and a second image forming unit comprising two developing means for developing the latent image of the latent image with a developer having a color different from that of the developer of the first image forming unit. In the image forming apparatus, comprising: an intermediate transfer body that sequentially superimposes and transfers toner images; and a transfer unit that transfers a color image formed on the intermediate transfer body to a sheet-like recording medium. In order to supply developer to the image carrier A developing agent carrying member extending in the axial direction of the image carrier, without the freely developing unit detachably attached to the apparatus body, at the same time placing the two developing units for each first and second image forming units And a moving direction perpendicular to the axial direction between a first position where the two developing units are attached and detached and a second position where the two developing units are positioned with respect to the image carrier. A slidable mounting means; and a moving means for sliding the mounting means between the first position and the second position; and in the vicinity of one axial end of the image carrier in the axial direction The apparatus main body is formed with a positioning hole for positioning by positioning one axial end of each developer carrier in the axial direction when the placing means occupies the second position. And the moving means is A rotatable operating means formed with a positioning guide that engages with the other axial end portion of each developer carrier when the placing means occupies the second position; and Reciprocating motion converting means for converting the rotational motion of the reciprocating motion into a reciprocating motion in the moving direction in which the placing means slides between a first position and a second position. The reciprocating motion conversion includes a pressed portion that presses both ends in the axial direction of the two developing units mounted on the mounting means in the moving direction, corresponding to the both ends in the axial direction. The means is moved in the axial direction by engaging the operating means cam formed in the operating means, the mounting means cam follower formed in each pressed portion, and the operating means cam. Cam follower and each mounting hand And a pedestal pressing member provided with a cam that presses and moves each of the pressed parts in the moving direction by engaging with a stepped cam follower .

According to a second aspect of the invention, in the image forming apparatus according to claim 1, wherein, when said placing means accounted for the second position, said operating means, of said two developing units and the image bearing member It also serves as positioning means for positioning at least one of them.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect , the urging means for urging the two developing units toward the image carrier is disposed in the mounting means. It is characterized by.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect , the urging means is an elastic member.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects , a non-contact type having a gap between the surface of the developer carrier and the surface of the image carrier. It is a development system.

According to the present invention, a novel image forming apparatus can be provided by solving the above-described problems. That is, according to the present invention, due to the above-described invention specific matter (hereinafter referred to as “configuration”) , a drum-shaped image is provided even though the developing unit is placed and moved at least twice as much as a normal weight. Provided is a compact and low-cost image forming apparatus that can perform an approach / separation operation with respect to a carrier and positioning a developer carrier with respect to an image carrier with high accuracy and a reduced number of parts. be able to.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments including the best mode for carrying out the present invention, examples, and the like will be described below with reference to the drawings. In the embodiments and the like, components such as members and components having the same functions and shapes are described with the same reference numerals, and the description thereof is omitted. In order to simplify the drawings and the description, even components that are to be represented in the drawings may be omitted as appropriate without being specifically described in the drawings. When a constituent element such as a published patent gazette is cited and described, the reference numeral is attached with parentheses to distinguish it from the embodiment and the like.

First, the overall configuration and operation of a full-color image forming apparatus 100 as an example of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS.
The full-color image forming apparatus 100 is called a color laser printer in the embodiment. The full-color image forming apparatus 100 includes an image carrier drum 22a as a single image carrier on which an electrostatic latent image is formed by a laser beam 36a emitted from an optical scanning device 56 as an exposure unit, and the image carrier drum. A first image forming unit 91 including two developing units 31a and 31b which are arranged opposite to 22a and develop the electrostatic latent image on the image carrier drum 22a with at least two color developers. The image carrier drum 22b as a single image carrier on which an electrostatic latent image is formed by the laser beam 36b emitted from the optical scanning device 56, and the image carrier drum 22b. A developing unit 31c as two developing means for developing the electrostatic latent image on the carrier drum 22b with a developer of a color different from the developer of the first image forming unit 91; A second image forming unit 92 made of 1d, etc., an intermediate transfer belt 28 as an intermediate transfer member for transferring the toner images formed by the first and second image forming units 91 and 92 in a superimposed manner, A secondary transfer roller 39 as transfer means for transferring a color image formed on the intermediate transfer belt 28 to a transfer material (hereinafter, more specifically described as “paper P”) as an example of a sheet-like recording medium; A paper feeding device 72 as a paper feeding means for feeding the paper P to the secondary transfer section between the intermediate transfer belt 28 and the secondary transfer roller 39, and fixing for fixing the color image transferred on the paper P. The image forming apparatus includes a fixing device 58 as a means, and a paper discharge device 61 as a paper discharge means for conveying and discharging the image-formed paper fixed by the fixing device 58 to a paper discharge tray 63 as a paper discharge table.

  The first and second image forming units 91 and 92 can also be referred to as first and second image forming units 91 and 92 or first and second image forming units 91 and 92. The image carrier drums 22a and 22b are well-known ones that can also be called photosensitive drums 22a and 22b. The two developing units 31a and 31b and the two developing units 31c and 31d, which are developing devices (developing devices), are attached to and detached from the apparatus main body 99 via mounting means and moving means, which will be described later, peculiar to the present invention. The process cartridge is made freely. As shown in both figures, the four developing units 31a, 31b, 31c, and 31d are arranged in the order of black (Bk), cyan (C), magenta (M), and yellow (Y) in this order from top to bottom. Toners are stored as developers of different colors. The black (Bk) toner stored in the developing unit 31a and the yellow (Y) toner stored in the developing unit 31 may be interchanged.

Around the image carrier drum 22a in the first image forming unit 91, on the surface of the photoreceptor of the image carrier drum 22a in order from the upstream side to the downstream side in the rotation direction (clockwise) indicated by the arrow in the drawing. In order to repeatedly form a cyan (C) image and a black (Bk) image, a charging roller 21a is provided as a charging means for uniformly charging the surface of the image bearing drum 22a. A charging device, a laser beam 36a emitted from the optical scanning device 56 to form an electrostatic latent image on the surface of the photosensitive member, and an agent carrying means / developer that carries cyan (C) toner as a developer. developing with a developing unit 31b including a developing roller 32b or the like as a support, the developing roller 32a such as a bearing for agent carrying means, the developer carrying member a black (Bk) color toners The two-color toner images developed by the two developing units 31a and 31b arranged opposite to the image carrier drum 22a across the knit 31a and the intermediate transfer belt 28 are primarily transferred onto the outer peripheral surface of the intermediate transfer belt 28. A primary transfer roller 29a as a primary transfer means, a cleaning blade 23a for scraping and cleaning the residual toner on the image carrier drum 22a after the primary transfer, and transporting the scraped residual toner to a waste toner bottle (not shown). And a cleaning device as a cleaning means provided with a toner conveying screw 24a and the like.

  The image carrier drum 22a, the charging device disposed around the image carrier drum 22a, and the cleaning device constitute a first image carrier unit that substantially integrates them. In both figures, reference numeral 20a indicated by a one-dot chain line indicates a first image carrier unit housing which is disposed in the apparatus main body 99 and forms a housing for attaching and holding the respective devices of the first image carrier unit. Show.

Similarly, around the image carrier drum 22b in the second image forming unit 92, the photosensitive member of the image carrier drum 22b is sequentially arranged from the upstream side to the downstream side in the rotation direction (clockwise) indicated by an arrow in the drawing. A charging roller 21b in contact with the surface of the photoconductor as a charging means for uniformly charging the surface of the photoconductor of the image carrier drum 22b in order to repeatedly form a yellow (Y) image and a magenta (M) image on the surface. , A laser beam 36b emitted from the optical scanning device 56 to form an electrostatic latent image on the surface of the photosensitive member, and an agent carrying means for carrying yellow (Y) toner as a developer - Preparations a developing unit 31d including a developing roller 32d and the like as a developer bearing member, the developing roller 32c or the like as a magenta (M) supported for agent carrying means, the developer carrying member a toner The two-color toner images developed by the two developing units 31c and 31d that are arranged opposite the developing unit 31c and the image carrier drum 22b with the intermediate transfer belt 28 interposed therebetween are placed on the outer peripheral surface of the intermediate transfer belt 28. A primary transfer roller 29b as a primary transfer means for next transfer, a cleaning blade 23b for scraping and cleaning the residual toner on the image carrier drum 22b after the primary transfer, and a waste toner bottle (not shown) for scraping the residual toner. And a cleaning device as a cleaning means provided with a toner conveying screw 24b and the like for conveying the toner.

  The image carrier drum 22b, the charging device disposed around the image carrier drum 22b, and the cleaning device constitute a second image carrier unit that substantially integrates them. In both figures, a reference numeral 20b indicated by a one-dot chain line indicates a second image carrier unit housing that is disposed in the apparatus main body 99 and has a housing shape for mounting and holding the respective devices of the second image carrier unit. Show.

  As described above, one image carrier drum 22a combined with the two development units 31a and 31b, the cleaning blade 23a and the charging roller 21a that are in contact with the image carrier drum 22a, and the like form the first image forming unit 91. It is composed. Similarly, one image carrier drum 22b combined with the two developing units 21c and 21d, the cleaning blade 23b that contacts the image carrier drum 22b, the charging roller 21b, and the like constitute a second image forming unit 92. ing.

  As shown in FIG. 1 and FIG. 3, the first image carrier unit and the second image carrier unit mainly perform different operations with substantially the same configuration except for the color of the toner. Therefore, in the description of the configuration, the reference numerals “a” and “b” added to the end of the reference numerals representing the components constituting each image carrier unit are distinguished, and only one of them is described. The description of the other is omitted. Similarly, each of the developing units 31a, 31b, 31c, and 31d performs the same operation with the same configuration except for the color of the toner. Therefore, in the description of the configuration, each developing unit 31a, The development unit 31a will be described as a representative example by distinguishing them by adding “a”, “b”, “c”, and “d” to the end of the symbols representing the components 31b, 31c, and 31d. Thus, the description of the other developing units 31b, 31c, 31d is omitted.

The end plate (flange) of the image carrier drum 22a is rotatably supported by being fitted into a shaft-like positioning boss 25a disposed on the first image carrier unit housing 20a (device main body 99 side). The hole to be made is formed. The image carrier drum 22a is supported so as to be rotatable clockwise in both drawings via a positioning boss 25a of the first image carrier unit housing 20a. The positioning boss 25a serves as a positioning main reference for the first image carrier unit. Similarly, the positioning boss 25b serves as a positioning main reference for the second image carrier unit.
2 and 3, reference numeral 35 denotes a long hole formed in the first image carrier unit housing 20 a, and reference numeral 34 denotes a rotation of the first image carrier unit by fitting into the long hole 35. Each of the positioning shafts used as a stop is shown. Each positioning shaft 34 serves as a positioning subordinate reference for the first and second image carrier units.

  The intermediate transfer belt 28 is an endless belt, and is looped around a driving roller 26, a driven roller 27, a tension roller 27-1, and two primary transfer rollers 29a and 29b. It is arranged to move. The intermediate transfer belt 28, the driving roller 26, the driven roller 27, the tension roller 27-1, and the two primary transfer rollers 29a and 29b constitute an intermediate transfer unit.

  On the side of the apparatus main body 99 facing the driven roller 27 across the intermediate transfer belt 28, a scraping blade that scrapes off the toner remaining on the intermediate transfer belt 28 after the secondary transfer and a transport for collecting the scraped residual toner. A belt cleaning device 30 including a screw or the like is disposed. The belt cleaning device 30 is displaceably provided at a position indicated by a solid line where the scraping blade scrapes off the toner remaining on the intermediate transfer belt 28 and a position indicated by a two-dot chain line where the toner is not scraped off.

In FIG. 3, reference numeral 54a denotes a developing unit housing that rotatably supports a pair of left and right agitators 52a and 53b that are a toner stirring roller 51a and a toner stirring member, including a developing roller 32a that constitutes the developing unit 31a.
The agitators 52a and 53b have a function of conveying the toner filled or contained in the outer periphery to the toner supply roller 51a while agitating the toner. The toner supply roller 51a supplies the agitated and conveyed toner to the developing roller 32a. Each has a function of supplying to adhere.
A leaf spring-like developing blade 50a for equalizing the amount of toner adhering to the developing roller 32a is attached and fixed to the developing unit housing 54a via a screw at the lower left in the drawing of the developing roller 32a.

A negative bias voltage in which alternating current and direct current are superimposed is applied to a cored bar of the developing roller 32a of the developing unit 31a from a bias power source (not shown). A DC negative potential bias voltage is applied to each charging roller 21a, 21b from another bias power source (not shown).
Gap rollers (not shown) that determine the gaps between the surfaces of the developing rollers 32a and 32b and the surface of the image carrier drum 22a and between the surfaces of the developing rollers 32c and 32d and the surface of the image carrier drum 22b are provided on the developing rollers 32a, 32b, It is provided at both ends of the shafts 32c and 32d.
As described above, in this embodiment, the surfaces of the developing rollers 32c and 32d as the agent carrying means and the image carrier drum are provided between the surfaces of the developing rollers 32a and 32b as the agent carrying means and the surface of the image carrier drum 22a. A non-contact developing system having a gap between each surface and the surface of 22b is employed. In the present embodiment, the intermediate transfer belt 28 is disposed so as to be inclined with respect to the horizontal line, and the first and second image forming units 91 and 92 are disposed in a space below the left inclined surface of the intermediate transfer belt 28. In addition, by arranging the fixing device 58 and the paper discharge device 61 around the space above the right inclined surface of the intermediate transfer belt 28, the space is effectively used, and the entire full-color image forming apparatus 100 is reduced in size. .

The optical scanning device 56 is disposed below the second image forming unit 92. The optical scanning device 56 includes a laser diode (LD) that generates and emits laser light in accordance with an image signal, a polygon mirror 57 that scans laser beams 36a and 36b that are laser light emitted from the LD, and the like. A laser beam scanning optical system is provided, and the surface of the photoreceptor of each image carrier drum 22a, 22b is exposed by each laser beam 36a, 36b.
The paper feeding device 72 is disposed below the optical scanning device 56. The sheet feeding device 72 is provided with a sheet feeding cassette 75 having a bottom plate on which the sheets P are stacked and stored, and the uppermost sheet P disposed above the sheet feeding cassette 75 by a cooperative action with the separation pad 74. A sheet feeding roller 73 that separates and feeds each sheet, and a registration roller pair 71 that feeds the sheet P fed by the sheet feeding roller 73 to a secondary transfer unit described later at a predetermined timing. Yes. In the paper conveyance path from the paper feed roller 73 to the secondary transfer roller (nip) formed between the roller pair 71 and the secondary transfer roller 39 facing the driving roller 26, the paper P A paper guide plate for guiding is provided.

Above the secondary transfer portion, a fixing device including a fixing roller 59 and a pressure roller 60 having a heating source such as a halogen heater for fusing and fixing the toner images of the respective colors transferred onto the paper P, for example. 58 is arranged.
A paper discharge device 61 is disposed above the fixing device 58. The paper discharge device 61 includes a switching claw 65 configured to be swingable between a position indicated by a two-dot chain line and a position indicated by a solid line, and a fixed toner image formed thereon via a conveyance roller and a paper discharge guide plate. A paper discharge roller pair 62 that conveys the paper P and discharges it to the paper discharge tray 63, and a paper discharge tray that is disposed to the left of the paper discharge roller pair 62 and discharges and stacks the fixed paper P on which the toner image is formed. 63.
In FIG. 1, reference numeral 64 denotes a switchback by reverse conveyance of the paper discharge roller pair 62 through the swinging of the switching claw 65 to the position indicated by the two-dot chain line in the drawing in order to obtain images on both sides of the paper P. 1 shows a reversal conveying apparatus including a reversing conveying path and a reversing conveying roller for reversing a sheet P on which an image is formed on one side and feeding it again to a secondary transfer section via a registration roller pair 71.

  Based on the above-described configuration, an outline of the overall operation of the full-color image forming apparatus 100 will be described with reference to FIGS. 1 and 3. At this time, as shown in both figures, the developing rollers 32a and 32b of the two developing units 31a and 31b are respectively connected to the image carrier drum 22a, and the developing rollers 32c and 32d of the two developing unit rollers 31c and 31d are connected to each other. The image carrier drum 22b is positioned and mounted with a predetermined gap. The two developing units 31a and 31b and the two developing unit rollers 31c and 31d are positioned and can be developed. The position P2 is occupied.

When a full-color image formation signal is transmitted to a control device (not shown) of the full-color image forming apparatus 100 by a key operation on an operation panel (not shown) or from a personal computer (not shown), the first and second image formations are performed. The units 91 and 92 operate at predetermined timings to be described later.
First, the first image forming unit 91 operates. That is, when the image carrier drum 22a starts to rotate in the direction of the arrow (clockwise) in both drawings, the toner stains remaining on the peripheral surface of the image carrier drum 22a are cleaned by the cleaning blade 23a. Next, by the operation of the charging roller 21a, the peripheral surface of the cleaned image carrier drum 22a is charged to a uniform high potential and initialized. Next, the operation of the optical scanning device 56 irradiates the image carrier drum 22 a of the first image forming unit 91 with the laser beam 36 a. The image carrier drum 22 b of the second image forming unit 92 is irradiated with the laser beam 36 b by the operation of the optical scanning device 56. As a result, the peripheral surface of the image carrier drum 22a charged to a uniform high potential as described above is selectively exposed based on the image data, and the low potential portion where the potential is attenuated by this exposure and the initialization described above. An electrostatic latent image consisting of a high potential portion is formed on the image carrier drum 22a. Next, when the developing unit 31a is operated, black toner is transferred to the low potential portion (or high potential portion) of the electrostatic latent image, and a black toner image is formed (developed) on the image carrier drum 22a. The Then, the black toner image is transferred onto the intermediate transfer belt 28 by the rotational conveyance of the black toner image by the image carrier drum 22a.

The second image forming unit 92 operates in the same manner as described above in accordance with the timing at which the toner image on the intermediate transfer belt 28 comes into contact with the image carrier drum 22b. As a result, the electrostatic latent image on the image carrier drum 22b is converted into a toner image (development) with magenta toner, and the magenta toner image is rotated and conveyed by the image carrier drum 22b. The toner image is transferred onto the intermediate transfer belt 28 in a superimposed manner.
Subsequently, the intermediate transfer belt 28 circulates and the first image forming unit 91 is operated again in accordance with the timing at which the superimposed toner image reaches the contact portion with the image carrier drum 22a. By operating the unit 31b, the electrostatic latent image on the image carrier drum 22a is converted into a toner image with cyan toner, and the cyan toner image is converted by the rotational conveyance of the cyan toner image by the image carrier drum 22a. The toner image is further transferred onto the intermediate transfer belt 28 in a superimposed manner.

Finally, the second image forming unit 92 operates again in accordance with the timing at which the triple transferred toner image on the intermediate transfer belt 28 comes into contact with the image carrier drum 22b, and the developing unit 31d. The electrostatic latent image on the image carrier drum 22b is converted into a toner image with yellow toner, and the yellow toner image is triple-folded on the intermediate transfer belt 28 by the rotational conveyance of the yellow toner image by the image carrier drum 22b. Further transferred onto the toner image.
As described above, while the same image forming area on the intermediate transfer belt 28 sequentially passes through the two image forming units 91 and 92, the toner images are transferred one by one by the image forming units 91 and 92, respectively. While the image area on which the two colors are transferred and transferred on the intermediate transfer belt 28 passes through the two image forming units 91 and 92 again sequentially, the toner of a different color from the previous one by each of the image forming units 91 and 92. Since the image is transferred and transferred, the full-color toner image is transferred and transferred when the same image forming area passes through the image forming units 91 and 92 twice.

Finally, the intermediate transfer belt 28 on which the full-color toner image is formed by superimposing and transferring the four-color toner images continues to circulate, and the leading end of the full-color toner image is the secondary of the secondary transfer roller 39 arrangement portion. When the sheet feeding device 72 is operated in accordance with the timing of conveyance to the transfer unit, the uppermost sheet P of the sheet feeding cassette 75 is separated and fed into one sheet by the cooperative action of the sheet feeding roller 73 and the separation pad 74. The full-color toner image on the intermediate transfer belt 28 is transferred onto the sheet P by the secondary transfer roller 39 with respect to the sheet P that has been fed and fed out at the predetermined timing by the registration roller pair 71. The paper P on which the full-color toner image has been transferred is further conveyed to the fixing device 58, where it is melted and pressed and fixed, and a desired full-color image is formed on the paper P. The fixed paper P is conveyed by the paper discharge roller pair 62 and discharged onto the paper discharge tray 63.
On the other hand, after the transfer of the full color image, the intermediate transfer belt 28 is subjected to removal and collection of residual toner by the belt cleaning device 30.

  Although the above-described operation example is an operation at the time of full-color image formation, it goes without saying that a color image formation operation using at least two colors of toner or an image formation operation using monochrome toner including monochrome can be performed.

Next, with reference to FIG. 1 to FIG. 4, a mounting / demounting configuration of the developing unit (developing device) that is a feature of the present invention will be described.
As shown in FIGS. 1 to 4, the full-color image forming apparatus 100 includes a receiving platform 1 a as a mounting unit that simultaneously mounts two developing units 31 a and 31 b corresponding to the first image carrier unit; Corresponding to the second image carrier unit, it has a receiving base 1b as mounting means for mounting two developing units 31c and 31d at the same time.

The cradle 1a is moved to the first position P1 shown in FIG. 2 where the two developing units 31a and 31b are attached and detached by the moving means 70a shown in FIG. 4, and the two developing units 31a and 31b with respect to the image carrier drum 22a. It is configured to be movable between the second position P2 shown in FIG. Similarly, the cradle 1b moves the two developing units 31c and 31d to and from the first position P1 shown in FIG. 2 and the two developing units 31c and 31d by the moving means 70b shown in FIG. It is configured to be movable between a second position P2 shown in FIG.
Due to the specific configuration described later of each of the cradle 1a, 1b, the above-described placing means can also be called an attaching / detaching means.

In the following, since the cradle 1a and the cradle 1b are mainly different in arrangement position and the substantial configuration is the same and common, the cradle 1a will be described as a representative of the cradle 1b. The description will be omitted.
Similarly, since the moving means 70a and the moving means 70b are mainly different in arrangement position and have substantially the same common configuration, the moving means 70b will be described by using the moving means 70a as a representative. The description of will be omitted.

  The cradle 1a is formed with the two developing units 31a and 31b mounted at the same time, and is erected at the right end in FIG. 2, as shown by hatching in FIG. The protrusion 4 and the upper and lower placement portions, which are portions where the developing units 31a and 31b are placed, are integrally formed. The protrusion 4 serves as a guide when the developing unit 31a is attached to and detached from the cradle 1a, and prevents the developing unit 31a from being too close to the image carrier drum 22a. In addition, support pins 2 and 3 are integrally formed on the front side and the back side of the paper surface on the cradle 1a.

On the other hand, on the apparatus main body 99 side, a main body front side plate 98 and a main body rear side plate (not shown) which are provided on the front side and the back side of the paper and in which elongated holes 40a and 40b are respectively formed are fixed.
1 to 3, reference numeral 41a indicated by a two-dot chain line denotes a main body front plate on the apparatus main body 99 side on which the first image carrier unit including the image carrier drum 22a and the developing units 31a and 31b are mounted. The opening part formed in 98 is represented. Similarly, reference numeral 41b indicated by a two-dot chain line in both drawings denotes an opening formed in the main body front side plate 98 on which the second image carrier unit including the image carrier drum 22b and the developing units 31c and 31d are mounted. Represents.

The support pins 2, 3 provided integrally with the cradle 1 a are loosely fitted into the long holes 40 a, 40 b of the main body front side plate 98 and the main body rear side plate (not shown), so that the cradle 1 a is an image carrier. The drum 22a is guided so as to be able to reciprocate horizontally in a moving direction D perpendicular to the axial direction, which is the longitudinal direction of the drum 22a. Therefore, the long holes 40a and 40b of the main body front side plate 98 and the main body rear side plate (not shown) have a function as guide means for guiding the cradle 1a so as to reciprocate in the movement direction D. A pair of upper and lower elongated holes 9 are formed in the rear plate of the main body for fitting the end portions of the developing rollers 32a and 32b on the back side of the paper surface for positioning in the vertical direction. The double line in the elongated hole 9 forming portion indicates the aperture / thickness of the main body rear side plate (for example, sheet metal).
The cradle 1a is formed by a tension spring 8 as a biasing member stretched between a spring hooking member formed integrally with the main body front side plate 98 and the support pin 2, and a main body rear side plate (not shown). The side is always urged to move to the left in the moving direction D in FIG.

  A pair of upper and lower quadrangular empty wall-shaped casings provided with projecting claws on the inner side are formed at the left end of the upper and lower placement parts of the cradle 1a. Press members 7a and 7b having engaging claws formed on the upper and lower sides thereof are arranged so as to engage with the respective claws of the casing portion. And between the inner wall of each said housing part and each press member 7a, 7b, each developing unit 31a, 31b mounted on the receiving stand 1a is set to the direction which approaches image carrier drum 22a, ie, each developing Compression springs 6a and 6b as urging means or elastic members for always urging the units 31a and 31b in the direction of moving to the right in the movement direction D are mounted. Therefore, even after each developing unit 31a, 31b hits the image carrier drum 22a via the gap roller (not shown) by the pressing of each pressing member 7a, 7b accompanying the urging force of each compression spring 6a, 6b, a predetermined amount is obtained. Can be applied.

  As shown in FIG. 4, a pressed portion 5 is formed integrally with each of the cradle 1a, 1b. An arch-shaped pressed portion cam follower 5a that constitutes the moving means 70a is formed on the near side and the back side of the pressed portion 5 in the drawing. Between each pressed portion cam follower 5a in the pressed portion 5 and each housing portion, an opening 42 serving as an optical path of a writing / exposure laser beam is formed. As shown in FIG. 2 and FIG. 3, the optical path of the laser beam 36a is obstructed by the pressed portion 5 of the cradle 1b in the second image forming unit 92 on the lower side, and therefore at least on the cradle 1b side. The opening part 42 should just be formed. However, as described above, the first image forming unit is used in order to make the components of the first image forming unit 91 and the second image forming unit 92 common (i.e., to make components and parts common). It is desirable to use the portion to be pressed 5 of the cradle 1a on the 91 side in which the opening 42 is formed.

The moving means 70a is a manual lever 10a as a rotatable operating means manually operated by the user, as shown in detail in FIG. 4 by enlarging the part A surrounded by the one-dot chain line circle in FIGS. Reciprocating motion conversion means for converting the rotational motion of the manual lever 10a into the reciprocating motion in the moving direction D in which the receiving base 1a moves between the first position P1 and the second position P2.
The reciprocating motion converting means includes a cam portion 11a as an operating means cam formed integrally with the lower hinge portion 11 of the manual lever 10a, and a receiving means cam follower formed on the cradle 1a. The cam follower 5a is moved in the axial direction C of the image carrier drum 22a by engaging with the pressing portion cam follower 5a and the cam follower 5a is engaged with the cam follower 5a to be orthogonal to the axial direction C. A cam 37b for pressing and moving the cradle 1a in the moving direction D is mainly composed of a cradle pressing member 37 as a pressing means formed at both ends.

As shown in FIG. 4 and the like, the manual lever 10a has a rotating lid shape, and the manual lever 10a is integrally formed with a hinge portion 11 having a cylindrical shape at the upper and lower portions thereof. The manual lever 10a is attached by a pin 12 and a retaining ring 13 provided on the apparatus main body 99 side, and is rotatable about a pin 12 in a rotation direction B indicated by a solid line and a broken line arrow. The lower hinge portion 11 is integrally formed with the above-described cam portion 11a having a substantially involute curved surface.
The manual lever 10a is formed with positioning holes 16a and 17a that engage with manual lever positioning pins 18a and 19a planted on the front plate 98 side of the main body. Further, the manual lever 10a has a pair of upper and lower U-shaped positioning guides 14a for regulating the height direction of the shaft end on the front side of each developing roller 32a, 32b, and the paper surface of the image carrier drum 22a. Positioning holes 15a for positioning the front side are formed. Further, the manual lever 10a is integrally formed with a claw 44a for hooking on an opening 41a formed on the main body front side plate 98 to hold the closed state of the manual lever 10a.
That is, in the operation after mounting the two developing units 31a and 31b to be described later on the receiving base 1a, when the receiving base 1a on which the two developing units 31a and 31b are placed occupies the second position P2, the manual lever The positioning holes 16a, 17a of 10a engage with the manual lever positioning pins 18a, 19a on the front plate 98 side of the main body, and the positioning guide 14a of the manual lever 10a is at the shaft end on the front side of the developing rollers 32a, 32b. The manual lever 10a is engaged with the developing roller shaft end portions 33a and 33b, and the positioning hole 15a of the manual lever 10a is engaged with the positioning boss 25a on the front side of the image carrier drum 22a. Positioning face plate for positioning the two developing units 31a and 31b and the image carrier drum 22a on the front side of the paper surface (no positioning means) Positioning regulation member) also serves as.

As shown in FIG. 4, the cams 37b at both the left and right ends, which are also the front side and the back side of the pedestal pressing member 37, have a tapered shape with inclined surfaces of approximately 45 degrees, and the cam followers 37a are substantially fan-shaped. Make a shape.
An image indicated by a direction in which the front end of the cradle pressing member 37 is pressed against the cam portion 11a, that is, a broken line arrow, between the rear end of the cradle pressing member 37 and the main body rear plate (not shown). A compression spring 43 is mounted to urge the carrier drum 22a in the axial direction C. The cradle pressing member 37 is guided and supported by a guide member 38a disposed on the apparatus main body 99 side so that the position thereof does not change in the moving direction D (moving direction of the cradle 1a) indicated by the solid line and broken line arrows. It can slide smoothly in the axial direction C indicated by the solid line and the broken line.
The material of the manual lever 10a formed with the cam portion 11a, the cradle 1a, the pressed portion 5, the cradle pressing member 37, the guide member 38a, and the like is represented by the number of images formed by the full-color image forming apparatus 100. Depending on the frequency, in other words, depending on the replacement frequency of each developing unit 31a, 31b, 31c, 31d, in order to satisfy the required specifications and quality such as predetermined strength, predetermined wear resistance, friction coefficient of the slide part, etc. Further, an appropriate resin is selected in consideration of low cost and the like (for example, polycarbonate resin (PC), polyacetal resin (POM), etc.).

Next, an operation when the two developing units 31a and 31b are mounted on the receiving base 1a will be described.
As shown in FIGS. 2 to 4, the mounting operation of the two upper developing units 31a and 31b to the receiving base 1a and the mounting operation of the two lower developing units 31c and 31d to the receiving base 1b are as follows. Since it is almost the same except for a part of the exposure operation and the like, the description on the lower side is omitted by describing the upper side as a representative.

First, in the state where the full-color image forming apparatus 100 in the state shown in FIG. 2, that is, the manual lever 10a is opened and the two developing units 31a and 31b are not attached to the cradle 1a, the two developing units 31a and 31a, 31b is placed on the upper and lower pedestals 1a, and each developing unit 31a, 31b is inserted into the back side of the sheet with each projection 4 serving as a guide. At this time, shaft end portions of the developing rollers 32a and 32b on the back side of the drawing surface enter the long holes 9 of the rear plate of the main body.
Next, as shown in FIG. 4, when the manual lever 10a is rotated around the pin 12 in the rotation direction B indicated by the solid line arrow in the figure, the cam portion 11a of the manual lever 10a rotates in the same rotation direction B together. As a result, the cam follower 37a of the cradle pressing member 37 that is in contact with the cam portion 11a is slid in the axial direction C indicated by a solid arrow in the figure against the urging force of the compression spring 43.
At this time, the cams 37b at both ends of the cradle pressing member 37 are engaged with the pressed portion cam followers 5a at both ends of the pressed portion 5, so that the linear movement in the axial direction C of the pedestal pressing member 37 occurs. The cradle 1a is slid in the moving direction D indicated by the solid line arrow through the smooth guide of the pedestal pressing member 37 by the guide member 38a.
As described above, the movement of the cradle pressing member 37 in conjunction with the rotation of the manual lever 10a causes the developing rollers 32a and 32b of the developing units 31a and 31b to move closer to the outer peripheral surface of the image carrier drum 22a together with the cradle 1a. Can slide. Further, as described above, the opening 42 of the pressed portion 5 in the lower pedestal 1b serves as the optical path of the laser beam 36b. Therefore, as shown in FIG. 3, the pedestal pressing member 37 to the pedestal 1b. This pressing is performed outside the apparatus main body 99 with respect to the exposure width portion (exposure range) where the image carrier drum 22b is exposed and written by the laser beam 36b.

  Next, when the manual lever 10a is further rotated in the rotation direction B indicated by the solid line arrow, the gap roller (not shown) that determines the gap between the outer circumferential surface of each of the developing rollers 32a and 32b and the outer circumferential surface of the image carrier drum 22a becomes the image carrier drum. 22b Abuts against and strikes the outer peripheral surface. When the manual lever 10a is further rotated, the pressing members 7a and 7b provided on the cradle 1a press the developing units 31a and 31b closer to the image carrier drum 22a by the urging force of the compression springs 6a and 6b. . By the pressing of the pressing members 7a and 7b through the urging force of the compression springs 6a and 6b, the gap rollers provided on the developing rollers 32a and 32b of the two developing units 31a and 31b are surely connected to the image carrier drum 22a. Can be faced.

Finally, when the positioning holes 16a and 17a of the manual lever 10a are fitted and engaged with the positioning pins 18a and 19a provided on the main body front side plate 98, the positioning guides 14a for regulating the heights of the developing rollers 32a and 32b are formed. The shaft end portions 33a and 33b on the front side of each developing roller 32a and 32b are engaged, and the image carrier device positioning hole 15a is engaged with a positioning boss 25a provided at the shaft end of the image carrier drum 22a. Is positioned. That is, the manual lever 10a also serves to position the developing units 31a and 31b and the first image carrier unit on the front side of the sheet. Further, the claw portion 43a of the manual lever 10a is hooked on the opening 41a on the main body front side plate 98 side, so that the closed state of the manual lever 10a can be maintained.
The above-described operation is the same for the second image forming unit 92 on the lower side. The operation at the time of detaching the developing units 31a and 31b from the cradle 1a may be performed by reversing the above series of operations. At this time, the rotation direction B and the axial direction C indicated by the solid arrows at the time of the operation described above. Those skilled in the art can easily understand and implement by replacing the movement direction D with the rotation direction B, the axial direction C, and the movement direction D indicated by the broken arrows.

  As described above, according to the present embodiment, the above-described problems of the present invention can be solved, and the main object and the object of obtaining the advantages and effects described later by the above-described configuration and operation can also be achieved. That is, according to the present embodiment, in the hybrid type image forming apparatus having the above-described configuration, each developing unit or developing device is connected to the developing device (process cartridge) 31a, 31b, 31c, which is detachable from the apparatus main body 99. A receiving base 1 a (mounting means) configured to simultaneously mount two developing units 31 a and 31 b corresponding to the first image forming unit 91 and 2 corresponding to the second image forming unit 92. A receiving base 1b (mounting means) for simultaneously mounting the two developing units 31c and 31d. The receiving base 1a includes a first position P1 at which the two developing units 31a and 31b are attached and detached, and two developing units. The two developing units 31c and 31d are attached to and detached from the second position P2 for positioning 31a and 31b with respect to the image carrier drum 22a (image carrier). Each of the first position P1 and the second position P2 for positioning the two developing units 31c and 31d with respect to the image carrier drum 22b (image carrier). The number of parts can be reduced, and the compact and low-cost full color image forming apparatus 100 can be realized and provided.

  According to this embodiment, the moving means 70a for moving the cradle 1a between the first position P1 and the second position P2 includes a rotatable manual lever 10a (operation means) and rotation of the manual lever 10a. A reciprocating motion converting means for converting the motion into a reciprocating motion in the moving direction D in which the cradle 1a moves between the first position P1 and the second position P2; The moving means 70b that moves between the first position P1 and the second position P2 includes a rotatable manual lever 10b (operating means) and the rotational movement of the manual lever 10b in the first position P1 and the second position. Reciprocating motion converting means for converting to a reciprocating motion in the moving direction D in which the cradle 1b moves between the cradle 1 and P2, respectively, and configuring the cradle 1a and the cradle 1b at the first position P1. To move reliably between the first position P2 and the second position P2. Kill.

  According to the present embodiment, the reciprocating motion converting means includes a cam portion 11a (operating means cam) formed on each manual lever 10a, 10b and each object formed integrally on each cradle 1a, 1b. The pressed portion cam follower 5a (mounting means cam follower) formed in the pressing portion 5 and the cam portion 11a engage with each other in the axial direction C of the image carrier drums 22a and 22b (image carrier). A cradle pressing member 37 (pressing member) provided with a cam 37b that presses and moves each of the cradles 1a and 1b in a moving direction D perpendicular to the axial direction C by engaging the moved cam follower 37a and the pressed cam follower 5a. For example, a relatively simple configuration compared to the case where a reciprocating motion converting means using a link device or the like is adopted, thereby further reducing the number of parts and It is possible to provide an inexpensive image forming apparatus in transfected.

  Further, according to the present embodiment, the reciprocating motion converting means is set to be more than the exposure range in which the image carrier drums 22a and 22b are exposed by the laser beams 36a and 36b from the optical scanning device 56 (exposure means). By disposing outside the main body 99, space can be used efficiently, and a more compact image forming apparatus can be provided.

  According to this embodiment, when the cradle 1a on which the two developing units 31a and 31b are placed occupies the second position P2, the positioning holes 16a and 17a of the manual lever 10a are the manual levers on the front plate 98 side. In addition to engaging with the positioning pins 18a and 19a, the positioning guide 14a of the manual lever 10a is engaged with the developing roller shaft end portions 33a and 33b which are the shaft end portions on the front side of the paper surface of the developing rollers 32a and 32b. The manual lever 10a is positioned to position the two developing units 31a and 31b and the image carrier drum 22a by engaging the positioning hole 15a of the lever 10a with the positioning boss 25a on the front side of the image carrier drum 22a. In addition, the two developing units 31c and 31d are similarly mounted. When the cradle 1b occupies the second position P2, the positioning holes 16b and 17b of the manual lever 10b engage with the manual lever positioning pins 18b and 19b on the main body front plate 98 side, and the positioning guide for the manual lever 10b. 14b engages with the developing roller shaft end portions 33c and 33d, which are shaft end portions on the front side of the developing rollers 32c and 32d, and the positioning hole 15b of the manual lever 10b is positioned on the front side of the image carrier drum 22b. By engaging with the positioning boss 25b, the manual lever 10b is configured to serve as a positioning face plate (positioning means) for positioning the two developing units 31c and 31d and the image carrier drum 22b. This makes it possible to provide a compact and low-cost image forming apparatus.

  Further, according to the present embodiment, the compression springs 6a and 6b (biasing means) for biasing the two developing units 31a and 31b toward the image carrier drum 22a are disposed on the receiving platform 1a (mounting means) side. Similarly, compression springs 6a and 6b (urging means) for urging the two developing units 31c and 31d toward the image carrier drum 22b are disposed on the receiving base 1b (mounting means) side. By doing so, the two developing units 31a and 31b and the two developing units 31c and 31d placed on the receiving bases 1a and 1b are surely in the second position P2 (positions where positioning and development are possible). Can be positioned.

  According to the present embodiment, the biasing means is constituted by the compression springs 6a and 6b, which are elastic members, so that the biasing means has a simple configuration as compared with a biasing means using electromagnetic means such as a solenoid. Thus, the number of parts can be further reduced, and a compact and low-cost image forming apparatus can be provided.

Further, according to the present embodiment, there is a gap between the surfaces of the developing rollers 32a and 32b (agent carrying means) and the surface of the image carrier drum 22a (image carrier) in the two developing units 31a and 31b. Similarly, a gap is formed between the surface of the developing rollers 32c and 32d (agent carrying means) and the surface of the image carrier drum 22b (image carrier) in the two developing units 31c and 31d. By having a non-contact developing system, the two developing units 31a and 31b and the two developing units 31c and 31d on the first and second turns of the intermediate transfer belt 28 (intermediate transfer member) are mechanically retracted. A mechanism is not required, and an inexpensive and simple configuration can be achieved.
Needless to say, the object of the present invention includes obtaining the above-described advantages and effects in addition to the main object described in the problem column to be solved by the above-described invention.

As described above, the present invention has been described with respect to specific embodiments. However, the technical scope disclosed by the present invention is not limited to those exemplified in the above-described embodiments and the like. It will be apparent to those skilled in the art that various embodiments, modifications, and examples can be configured within the scope of the present invention in accordance with the necessity and application.
In the above-described embodiment, for the purpose of providing a low-cost image forming apparatus, the development unit of a one-component developer in which the developer is made of toner has been described to achieve this. If low cost is not desired, the present invention can be applied or applied mutatis mutandis even if a two-component developer comprising at least a toner and a carrier is used as the developer.

1 is a schematic configuration diagram of an entire full-color image forming apparatus showing an embodiment of the present invention. FIG. 3 is a cross-sectional view of the main part of the full-color image forming apparatus showing a state in which the manual lever is opened before mounting each of the two developing units on the upper and lower cradles of the apparatus main body. FIG. 3 is a cross-sectional view of the main part of the full-color image forming apparatus showing a state in which the manual lever is closed after the two developing units are mounted on the upper and lower cradles of the apparatus main body. FIG. 4 is a perspective view around a cradle and moving means (manual lever, cradle pressing member) in the full-color image forming apparatus.

Explanation of symbols

1a, 1b cradle (mounting means)
5a Pressed portion cam follower (cam follower for mounting means)
6a, 6b Compression spring (biasing means, elastic member)
7a, 7b Press members 10a, 10b Manual lever (operation means)
11a Cam part (cam for operation means)
14a, 14b Positioning guide (positioning means provided in the operating means)
15a Positioning hole (positioning means provided in the operating means)
22a, 22b Image carrier drum (image carrier)
28 Intermediate transfer belt (intermediate transfer member)
31a, 31b Development unit (two development units)
31c, 31d Development unit (two development units)
32a, 32b, 32c, 32d Developing roller (agent carrying means, developer carrying member)
36a, 36b Laser beam (exposure)
37 Receptacle pressing member (pressing means)
37a Cam follower (cam follower provided in the pressing means)
37b Cam (cam provided on the pressing means)
39 Secondary transfer roller (transfer means)
42 opening 56 optical scanning device (exposure means)
58 Fixing devices 70a, 70b Moving means 91 First image forming unit 92 Second image forming unit 98 Main body front side plate 99 Device main body 100 Full color image forming apparatus (image forming apparatus)
B Rotation direction (Rotation direction of operation means)
C axial direction (axial direction of image carrier)
D Moving direction (Moving direction of mounting means)
P paper (an example of a sheet-like recording medium, transfer material)
P1 1st position P2 2nd position

Claims (5)

A single drum-shaped image carrier on which a latent image is formed by exposure means, and two developments that are arranged opposite to the image carrier and develop the latent image on the image carrier with at least two color developers A first image forming unit comprising means, a single image carrier on which a latent image is formed by exposure means, and a latent image on the image carrier arranged opposite to the image carrier. The second image forming unit comprising two developing means for developing with a developer of a color different from the developer of the forming unit and the toner images formed by the first and second image forming units are sequentially superimposed and transferred. In an image forming apparatus comprising: an intermediate transfer body that transfers; and a transfer unit that transfers a color image formed on the intermediate transfer body to a sheet-like recording medium.
Each of the developing means includes a developer carrier extending in the axial direction of the image carrier so as to supply the developer to the image carrier, and forms a development unit that is detachable from the apparatus main body,
A first position where the two developing units are simultaneously mounted for each of the first and second image forming units , and the two developing units are attached and detached, and the two developing units are attached to the image carrier. Mounting means slidable in a movement direction perpendicular to the axial direction between the second position and positioning ;
Moving means for sliding the placing means between the first position and the second position;
Have
The main body of the image carrier in the vicinity of one axial end in the axial direction has one of the axial directions in each developer carrier when the placing means occupies the second position. A positioning hole for positioning by inserting the shaft end is formed,
The moving means is rotatable in which a positioning guide is formed to engage with the other axial end portion of each developer carrier when the placing means occupies the second position. Operating means, and reciprocating motion converting means for converting the rotational movement of the operating means into a reciprocating motion in the moving direction in which the placing means slides between a first position and a second position,
The placing means corresponds to the both end portions in the axial direction of the pressed portions that press both end portions in the axial direction of the two developing units placed on the placing means in the moving direction. Each has
The reciprocating motion converting means is engaged with the operating means cam formed on the operating means, a mounting means cam follower formed on each of the pressed parts, and the operating means cam to engage the axial direction. And a pedestal pressing member provided with a cam that presses and moves each of the pressed parts in the moving direction by engaging with the cam follower for each mounting means and the cam follower for each mounting means. Forming equipment. The image forming apparatus according to claim 1.
The image is characterized in that when the placing means occupies the second position, the operating means also serves as a positioning means for positioning at least one of the two developing units and the image carrier. Forming equipment. The image forming apparatus according to claim 1 or 2,
2. An image forming apparatus according to claim 1, wherein a biasing unit that biases the two developing units toward the image carrier is disposed in the mounting unit . The image forming apparatus according to claim 3.
The image forming apparatus according to claim 1 , wherein the biasing means is an elastic member . The image forming apparatus according to any one of claims 1 to 4 ,
An image forming apparatus comprising a non-contact developing system having a gap between a surface of the developer carrier and a surface of the image carrier .

Images