JP2690157B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer that employs an electrophotographic system.

(Prior Art) In a conventional copying machine or laser beam printer,
The resolution of the formed image is usually fixed to the most frequently used one, or can be changed to have versatility.

(Problems to be Solved by the Invention) However, in an image forming apparatus having a fixed resolution, if the resolution is low, it is not possible to sufficiently output an image such as a photograph requiring high resolution, and the resolution is high. In this case, even when a normal character or the like that requires only a low resolution is output at a high resolution, there is a drawback that it takes a lot of time to output.

Further, in an image forming apparatus capable of changing the resolution, when a photograph and characters are mixed on the same document, either the photograph or the character resolution is selected, and the photograph and the character are output at the same resolution. , It is necessary to ignore the resolution of either the character or the photograph, or to output the character or photograph once and then to output it again on the same transfer material at a different resolution. In this case, it takes time and the same transfer Since the material has to be manually fed twice, there is a drawback that the image tends to be misaligned.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of forming images at a plurality of resolutions at once.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an image forming apparatus for forming an image on a transfer material, comprising: a. A photosensitive drum, and a process means that acts on the photosensitive drum. A first mounting portion for removably mounting a first image forming unit which has an image formation at a first resolution upon image formation; b. A photosensitive drum; and a process means acting on the photosensitive drum. And a second mounting portion for detachably mounting a second image forming unit for forming an image at a second resolution higher than the first resolution for image formation, and c. When a transfer material feeding cassette having a feeding portion for feeding the transfer material to the first image forming unit mounted in the first mounting portion and a support portion is mounted, the transfer material to be loaded is mounted. The second package And feeding means for feeding the second image forming unit to be mounted on the section, in order to perform multiple image formed by different resolutions,
The transfer material on which the image is formed at the first resolution by the first image forming unit mounted on the first mounting portion is once received on the transfer material feeding cassette, and is then fed back. Means for feeding to the second image forming unit mounted on the second mounting portion to form an image at the second resolution; and the transfer material feeding cassette from the supporting portion. When the supporting member is detached and the supporting portion is extended, the transfer material on which the image is formed by the first image forming unit mounted on the first mounting portion is transferred to the second mounting portion. A feeding / conveying / combining unit having: a discharging unit configured to discharge from the apparatus main body without feeding to the mounted second image forming unit; and e. The first mounting unit mounted on the first mounting unit. 1 Image forming unit and the second mounting part And a discharge tray for receiving the transfer material discharged from the apparatus body after an image is formed by at least one of the second image forming units, and performs multiple image formation in which a character image and a photographic image are present. At this time, the character image is formed by the first image forming unit mounted on the first mounting portion, and the photographic image is formed by the second image forming unit mounted on the second mounting portion from the character image. It is also characterized in that images can be formed with high resolution.

(Operation) According to the present invention, a multiple image including a character image and a photographic image can be formed on one surface of a transfer material at a first resolution and a second resolution in a short time. In addition to being able to form the image, the image having the first resolution or the second resolution can be formed on one surface of the transfer material in a short time.

(Embodiment) An embodiment of the present invention will be described below by taking a laser beam printer as an example with reference to the accompanying drawings.

First, the basic structure of the present invention and its operation will be described with reference to FIGS.

In FIG. 1, reference numeral 20 denotes a photosensitive drum which is an image carrier, and around the photosensitive drum 20, a developing device 21, a primary charger 22, a cleaning device 23, and a transfer charger 24 are arranged.
These devices, including 20, make up the electrophotographic process tool. An optical system unit composed of a laser scanner 26, a folding mirror 27 and the like is disposed on the upper right side in FIG. 1 of the electrophotographic process means, and a fixing device 28 is disposed on the left side.
Further, a fixing unit including a transfer guide 29 for the transfer material (transfer paper) P and the like is provided.

When the image light L from the laser scanner 26 is exposed on the photosensitive drum 20 uniformly charged by the primary charger 22 through the folding mirror 27, an electrostatic latent image is formed on the photosensitive drum 20. An image is formed, and the electrostatic latent image is visualized through the developer (toner) in the developing device 21 and converted into a toner image. The toner image is transferred to the transfer paper P by the transfer charger 24.
The transfer paper P carrying the toner image is transferred to a fixing device 28 via a transport guide 29, and the toner image is heated and fixed as a permanent image.

Here, the photosensitive drum 20, the developing device 21, the primary charging device 22, and the cleaning device 23 are integrally incorporated in a cartridge container 25a to form a process cartridge 25, and replacement or consumables due to the life of the process equipment (for example, The maintenance of the process cartridge 25 is facilitated by replacing the entire process cartridge 25 with respect to the replacement of toner, etc.).

Further, an optical system unit such as a laser scanner 26, an electrophotographic process means such as a process cartridge 25, and a fixing unit 28
The fixing means such as is positioned and supported in the unit frame 30 integrally formed of glass reinforced plastic from the upper right side to the lower left side in FIG. 1 to form the first image forming unit 2. The process cartridge 25 is detachably attached to the unit frame 30. The upper part of the unit frame 30 is an opening / closing door 32 that can be opened and closed vertically via a hinge 31 to facilitate maintenance such as jam clearance and replacement of the process cartridge 25. The first image forming unit 2 is positioned on the base 1a of the image forming apparatus main body 1 and is supported by the base 1a. The unit frame 30 is positioned and fixed to the base 1a by fitting and fixing the boss 33 provided on the unit frame 30 into the positioning hole of the base 1a. Therefore, the first image forming unit 2 is integrally detachable from the image forming apparatus main body 1.

By the way, a first registration roller 7 is arranged on the right side of the first image forming unit 2 in FIG. 1 so as to be close to the photosensitive drum 20, and on the further right side of the first registration roller 7, there is a paper feed cassette. First and second sheet feeding units 4 and 5 configured by 41 and 43 and sheet feeding rollers 40 and 42 are arranged.
Transfer paper P between the paper feeding units 4, 5 and the registration roller 7
Is provided. Incidentally, it is assumed that transfer papers P having different sizes are stacked in the first and second paper feeding units 4 and 5, respectively. Further, the transfer paper P is provided on the left side of the first image forming unit 2 in FIG.
Is provided with a flapper 8 capable of changing the moving direction of the paper, and a third paper feeding unit 9 including a paper feeding cassette 45, a paper feeding roller 44, etc. is provided further to the left of the flapper 8. There is.

A transfer guide 10 for the transfer paper P is provided obliquely above and above the first image forming unit 2 from the flapper 8.
A second registration roller 11 is arranged on one end side of the conveyance guide 10. A fourth sheet feeding unit 12 including a sheet feeding cassette 47, a sheet feeding roller 46 and the like is disposed on the left side of the second registration roller 11, and transfer sheets from the third and fourth sheet feeding units 9 and 12 are transferred. P can be conveyed toward the second registration roller 11. The sizes of the transfer sheets P in the third and fourth sheet feeding units 9 and 12 may be the same or different.

Here, as shown in FIG. 3, when the paper feeding cassette 45 of the third paper feeding unit 9 is removed, the supporting portion of the paper feeding cassette 45 can be extended, and the transfer paper P ejection tray can be extended. 17 can be formed. In this case, the paper feed roller 44 is reversely rotated in the direction of the arrow in the figure, and is configured to function as a paper discharge roller.

Further, a second image forming unit 3 having exactly the same function as the first image forming unit 2, its internal configuration, size and the like is fixedly positioned above the first image forming unit 2. The second image forming unit 3 is attached to the first image forming unit 2 in the opposite direction to the right and left, its scanner unit 26 'is disposed above the fourth paper feeding unit 12, and the photosensitive drum 20' of the process cartridge 25 'is Positioned right above the photosensitive drum 20 of the first image forming unit 2 and in proximity to the second registration roller 11, and fixing unit 28 'is positioned above the scanner unit 26 of the first image forming unit 2. Has been done. The second image forming unit 3 is positioned and fixed by fitting the boss 33 'of the unit frame 30' into a positioning hole provided in the opening / closing door 32 of the unit frame 30 of the first image forming unit 2. . Various images can be formed by using the second image forming unit 3 together with the first image forming unit 2. Reference numeral 13 denotes a paper discharge tray.

Next, referring to FIG. 2, the first and second image forming units 2, 3
The drive force transmission mechanism to the motor will be described.

FIG. 2 is a view of the image forming apparatus main body 1 to which the second image forming unit 3 is attached as seen from above, for driving the photosensitive drum 20 ′ protruding outward from the process cartridge 25 ′ in the second image forming unit 3. Drum gear 50 meshes with the drive gear 53 of the fixing device 28 'via the two idler gears 51, 52, and the drum gear 50 causes the driving gear 53 of the fixing device 28'.
Is rotatable. Further, the driving force from the main motor 14 provided at the corner of the image forming apparatus main body 1 is the gear train 15
Via the scanner unit 2 of the second image forming unit 3
The final drive gear 16 of the gear train 15 extends from the lower side on the 6'side toward the second registration roller 11 and meshes with an idler gear 54 which meshes with the drum gear 50 through a gear entry hole 34 'provided in the unit frame 30'. Then, the rotational force of the main motor 14 is transmitted to the drum gear 50.

Further, the transmission of the driving force from the main motor 14 to the first image forming unit 2 is also transmitted to the vicinity of the first registration roller 7 via another gear train, and the final drive gear of this gear train is transmitted. Similarly to the second image forming unit 3, a drum gear (corresponding to 55 in FIG. 2) of the photosensitive drum 20 is passed through a gear entry hole (corresponding to 35 ′ in FIG. 2) provided in the unit frame 30. Gear) which meshes with an idler gear (corresponding to 56 in FIG. 2). The transmission of power from the drum gear of the first image forming unit 2 to the drive gear of the fixing device 28 is exactly the same as that of the second image forming unit 3.

In addition, power supply to the first and second image forming units 2 and 3 will be described.
Low-voltage power supply for supplying DC power to each unit in the image forming main body 1, mainly supplying high-voltage power to the primary chargers 22 and 22 'in the process cartridges 25 and 25' and the developing devices 21 and 21 '. The high-voltage transformer unit for controlling each unit, the DC controller unit including the CPU for controlling each unit, and the like are all provided on the image forming apparatus main body 1 side, and the first and second image forming units 2 and 3 do not include these components. The power source from the above will be connected through the terminals and the like. Here, the main part of the power supply unit is arranged on the image forming apparatus main body 1 side as described above in order to keep the cost of the second image forming unit 3 which may be used as an option particularly low. is there.

 Next, the operation of the image forming apparatus will be described.

First, the case where images are formed on different transfer papers P by the first and second image forming units 2 and 3 will be described.

First, the operation of the first image forming unit 2 will be described. The first resist is fed from the paper feed cassette 41 or 43 of either the first or second paper feed unit 4 or 5 via the paper feed roller 40 or 42. The transfer paper P sent to the roller 7 is timed by the first registration roller 7 and is supplied from the supply hole 36 of the transfer paper P provided in the unit frame 30 of the first image forming unit 2 to the first transfer roller 36. The image enters the image forming unit 2, the image is transferred and fixed on the upper surface of the image forming unit 2, and the image is conveyed to the flapper 8 from the discharge hole 37 of the transfer paper P also provided in the unit frame 30 on the fixing device 28 side. Then, when the flapper 8 is positioned as shown by the solid line, the transfer sheet P is conveyed toward the third sheet feeding unit 9. In this case, the paper feeding cassette 45 of the third paper feeding unit 9 is removed, the supporting portion thereof is extended a little longer to form the paper ejection tray 17, and the paper feeding roller 44
Reversely functions as a paper discharge roller, and the transfer paper P is stacked on the paper discharge tray 17 in a face-up state with the image side facing up.

On the other hand, simultaneously with the image formation in the first image forming unit 2, the transfer paper P from the fourth paper feeding unit 12 is conveyed into the second image forming unit 3 and an image is formed on the transfer paper P. The transfer paper P is stacked on the paper discharge tray 13.

That is, the first and second image forming units 2 and 3 can be used as completely independent image forming apparatuses. In particular, in a normal double-sided or multi-printable image forming apparatus,
In the image forming apparatus according to the present invention, the first,
Even if one of the second image forming units 2 and 3 fails, there is an advantage that the other image can be formed.

Numeral 38 denotes a transfer regulating plate for the transfer paper P on the door 32,
If necessary, rotate around the fulcrum 38a and use it upright.

Next, a case of performing double-sided printing in which images are formed on both sides of the transfer paper P will be described. The first and second paper feeding units 4 and 5 are used to perform the first registration roller 7 through the first registration roller 7.
The transfer paper P having the image transferred and fixed on its upper surface side by the image forming unit 2 passes through the conveyance guide 10 with the image forming surface facing downward by the flapper 8 positioned as shown by the chain line, and then passes through the second resist. It is conveyed toward the roller 11.
Then, the transfer paper P is conveyed to the inside of the second image forming unit 3 with the timing adjusted by the second registration roller 11, and the toner image formed around the photosensitive drum 20 'is passed through the transfer charger 24'. Is transferred to the upper surface of the transfer paper P, and the toner image is fixed by the fixing device 28 ', and then the paper is stacked on the paper discharge tray 13 outside the second image forming unit 3 in a double-sided printed state.

In this case, in the second image forming unit 3, the direction of the scanner unit 26 'is opposite to that of the first image forming unit 2, so that the scanning direction (image writing direction) in the main scanning direction is also opposite. As a countermeasure against this, for example, the image forming apparatus main body 1 or the like can store the image information for one line or several pages once in a RAM or the like, and then read the image information from the left and right opposite directions.

When the image is formed on only one side of the transfer paper P, the transfer paper P may simply pass through the second image forming unit 3.

Also, when performing multiple printing on one transfer sheet P,
For example, the process cartridge 25 'in the second image forming unit 3 may be replaced with a cartridge having a different toner color from that in the first image forming unit 2, and an image is formed on the upper surface of the first image forming unit 2. After the formed transfer paper P is once positioned on the paper feed cassette 45 of the third paper feed unit 9 via the flapper 8 positioned as shown by the solid line, this transfer paper P is placed in the third paper feed unit. 9 paper feed rollers
The transfer paper P is conveyed from the conveyance guide 10 to the second registration roller 11 via the transfer roller 44, and the transfer paper P is conveyed into the second image forming unit 3 by the second registration roller 11 at the same timing. It is sufficient that the second image forming unit 3 forms an image on the P image formed by the first image forming unit 2.

As is apparent from the above description, by using the first and second image forming units 2 and 3, double-sided printing, multi-printing and single-sided printing on two transfer papers P can be performed by this image forming apparatus. Although printing is possible at the same time, the resolution of an image formed by this image forming apparatus will be described below.

The resolution of the image changes depending on the functions of the laser scanners 26 and 26 '.
If the exposure to 0,20 'is made slowly and minutely, a clear image will be formed in the details and the resolution of the image forming apparatus will be increased. Image is formed, and the resolution of the image forming apparatus decreases. In the case of photographs and the like among manuscripts, the image forming apparatus is required to have high resolution (for example, about 600 dpi),
A low resolution (for example, about 300 dpi) is sufficient for ordinary characters.

Here, in a normal image forming apparatus, there are many cases in which the resolution is constant or can be switched to about two types. In such a case, for example, characters and photographs are mixed in the image in the original document. In this case, if the image forming resolution of the apparatus is increased, it takes a long time to form the image. If the image forming resolution is lowered, it is impossible to form a clear image on a photograph or the like.

Therefore, in the present invention, the laser scanners 26 and 26 'of the first and second image forming units 2 and 3 are variously selected, and even when characters and photographs are mixed in the manuscript, it becomes clear.
In addition, it enables quick image formation. Hereinafter, each case will be described.

First, if the resolution of the image in the first image forming unit 2 is set to, for example, 300 dpi, in the case where a document requiring a high resolution (such as a photograph) and a document having a normal resolution (such as a letter) are mixed. However, first, a good image with a normal resolution is formed on the transfer paper P from the first or second paper feeding unit 4 or 5 by the first image forming unit 2, and then the second image forming unit is formed on the same transfer paper P. It is only necessary to form an image for which high resolution is required by 3 so as to perform multiple printing, and stack this on the tray 13. By doing so, even if an image requires a plurality of types of resolutions (two types in the case of this embodiment) in a document, the images can be clearly and quickly displayed on the transfer paper by the image forming apparatus. Can be formed.

In such a case, even if two originals require different resolutions for image formation, these images can be simultaneously formed by the first and second image forming units 2 and 3. it can. That is, when an image of an original document which is required to have only a normal resolution is formed on the transfer paper P from the first or second paper feeding unit 4 or 5 by the first image forming unit and the transfer paper P is stacked on the tray 17. At the same time, the image of the document requiring high resolution is transferred from the fourth paper feeding unit 12 to the transfer paper P.
The transfer sheet P may be formed on the tray 13 by the second image forming unit 3, and the transfer sheet P may be stacked on the tray 13. Of course, it is also possible to form an image with a required resolution by using only one of the first and second image forming units 2 and 3.

Also, the resolution of the first image forming unit 2 for forming an image is set to, for example, 300 dpi, and the second image forming unit 3
If you can switch the resolution of the image of, for example, 400dpi and 600dpi, the character and the resolution of the photograph are not required in the document, but if there is an image that requires a higher resolution (400dpi) than the character, 1 image forming unit 2 300d
If an image that requires a resolution of pi is formed and an image that requires a resolution of 400 dpi is formed by the second image forming unit 3, the image forming apparatus can quickly and in accordance with the resolution required by the document. A clear image can be formed.

As is clear from the above description, according to the present embodiment, the first image formation in which the multiplex image including the character image and the photographic image is formed on one side of the transfer paper P at the first resolution and the second resolution The pattern, the second image forming pattern for forming the image of the first resolution on one surface of the transfer paper P, and the third image forming pattern for forming the image of the second resolution on the one surface of the transfer paper P are independent images. It can be realized by a forming apparatus or a low-cost and small-sized image forming apparatus. In particular, since the photographic image can be formed with the second resolution which is higher than the first resolution, the image can be formed more clearly.

In addition, the third paper feeding unit 9 that constitutes a feeding / delivery dual-use portion
Since the transfer material can be efficiently transported, the image formation of the three patterns can be realized in a short time and with a desired resolution by a single downsized image forming apparatus. it can.

In the above embodiments, the case where two image forming units are incorporated in the image forming apparatus main body 1 has been described, but the present invention is not limited to this, and three or four image forming units are incorporated to further provide a plurality of image forming units. It is also possible to form an image that requires a resolution at one time.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following remarkable effects can be obtained.

A first image forming pattern for forming a multiple image including a character image and a photographic image on one surface of a transfer material at a first resolution and a second resolution, and an image of the first resolution is formed on one surface of the transfer material. Realization of the second image forming pattern and the third image forming pattern for forming the image of the second resolution on one surface of the transfer material by a single image forming apparatus or a low cost and small image forming apparatus can do.
In particular, the photographic image has a second resolution higher than the first resolution.
Since the image can be formed with the resolution of, the image can be formed more clearly.

Since the transfer material can be conveyed efficiently because it has the "feeding / discharging / combining portion" as defined in the claims, the size of the image forming apparatus can be reduced to the above-mentioned 3
Image formation of one pattern can be realized in a short time and at a desired resolution.

[Brief description of the drawings]

FIG. 1 is a side sectional view of the image forming apparatus, FIG. 2 is a plan view of the image forming apparatus, and FIG. 3 is that a sheet feeding cassette is detached from a third sheet feeding unit and is used as a sheet discharging tray. FIG. 1 ... Image forming apparatus main body, 2 ... First image forming unit, 3 ... Second image forming unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Yakumachi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tsuyoshi Straw, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masato Otsuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshifumi Moriya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tadashi Yagi Tadashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroaki Miyake 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-60-48667 (JP, A) JP-A-60-47549 (JP, A) JP-A-63-39268 (JP, A) JP-A-63-315247 (JP, A) JP-A-60 −104 964 (JP, A) JP 64-56464 (JP, A)

Claims (1)

(57) [Claims] 1. An image forming apparatus for forming an image on a transfer material, comprising: a. A photosensitive drum and process means acting on the photosensitive drum, and forming an image at a first resolution in forming an image. A first mounting portion for removably mounting the first image forming unit; b. A photosensitive drum; and a process means that acts on the photosensitive drum, and has a first resolution higher than the first resolution in image formation. A second mounting portion for removably mounting a second image forming unit that forms an image at a high second resolution; and c. The transfer material to be stacked is mounted on the first mounting portion. 1 When the transfer material feeding cassette having the feeding portion for feeding to the image forming unit and the d. Support portion is mounted, the loaded transfer material is loaded in the second mounting portion to the second image. Feed to the forming unit And a transfer unit, which transfers the transfer material image-formed at the first resolution by the first image forming unit mounted on the first mounting unit to perform multiple image formation at different resolutions. After receiving once on the transfer material feeding cassette,
Means for feeding back to the second image forming unit mounted on the second mounting portion to carry out reverse feeding to form an image at the second resolution; and the transfer material feeding cassette. When the support member is detached from the support portion and the support portion is extended, the transfer material on which the image is formed by the first image forming unit attached to the first attachment portion A feeding / transporting section having a discharging means for discharging from the apparatus main body without feeding to the second image forming unit mounted on the mounting section of e. A discharge tray for receiving the transfer material discharged from the apparatus body after an image is formed by at least one of the first image forming unit and the second image forming unit mounted on the second mounting portion. And has a character image and a photo When performing multiple image formation in which there is a character image, the character image is formed by the first image forming unit mounted on the first mounting portion, and the photographic image is formed on the second mounting portion by the first image forming unit. An image forming apparatus capable of forming an image with a resolution higher than that of a character image by using two image forming units.