JP3330636B2 - Color image forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus applied to a color copying machine, a color facsimile, a color printer, and the like, and more particularly to a color image forming apparatus using sheets of various sizes.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic image forming method of forming a latent image by irradiating a uniformly charged photoreceptor with a laser beam to form an electrostatic latent image and developing the electrostatic latent image to form a toner image is known. A color image forming apparatus that synthesizes a plurality of color toner images on a photoconductor by repeating a plurality of times and transfers the synthesized toner image to a transfer material to form a color image is known. It is applied to facsimile, color printer, etc. In such a color image forming apparatus, various types of transfer materials (transfer papers) of a fixed size such as A3, A4, B4, and B5 can be usually used. It is necessary to install a plurality of paper feed trays exclusively for storing the paper in the apparatus, or to make a universal tray and set it in the main body according to each size.

[0003]

However, when a plurality of paper feed trays according to the size of paper are installed in the apparatus, a plurality of paper feed tray installation sections must be provided in the image forming apparatus main body. A plurality of paper feed rollers, feed paths, etc. must be provided in accordance with the number of paper feed trays. There is also a method in which the paper feed unit is replaced at one location according to the paper size.In this case, however, the paper feed cassette must be replaced every time the paper size is changed, which is a laborious operation. It takes. The present invention has been made in view of the above circumstances, and the number of paper feed trays is small, the apparatus can be downsized, and images can be formed on transfer materials of various sizes larger than the number of paper feed trays. It is an object to provide a color image forming apparatus.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for forming an electrostatic latent image by irradiating a uniformly charged photosensitive member with a laser beam, and developing the electrostatic latent image. A multi-color toner image is synthesized on a photoreceptor by repeating electrophotographic image formation a plurality of times to form a color image, and the synthesized toner image is transferred to a transfer material to form a color image. a forming apparatus, comprising: means for cutting the transfer material for transferring the toner image on the photosensitive member, and means for feeding the front of the cut transfer material to the transfer portion, a rear portion of the cut transfer material Guide means for guiding in a different direction from the transfer unit,
And has a means for stocking the rear portion of the guide transfer material.

In the color image forming apparatus of the present invention,
In other words, the means for stocking the rear part of the transfer material
Switch the pair of switchable grip rollers and stop the
The transfer material for transferring the toner image on the photoreceptor is cut from a large-size transfer material (A3, B4, etc.) to a half-size small-size transfer material (A4, B5, etc.) .
In this case, the first half of the cut transfer material is fed to the transfer unit, and the second half of the cut transfer material is fed by the guide means.
Guided to the paper output tray, guided to the paper output tray side
Grip the rear end of the transfer material
Tsu held to the paper discharge tray at up state, the time of feeding again the transfer unit transfer material latter part of the held, the glycidyl
Rotate the roller pair in the opposite direction to discharge the second half of the transfer material.
From the ray to the transfer section
It is characterized by being transported .

[0006]

In the color image forming apparatus of the present invention, only a large-sized transfer material (transfer paper) is set in the paper feed tray of the apparatus main body, and the transfer is performed in response to an operator's key input or image information (size information). When a small-size transfer material is specified, the large-size transfer material fed from the paper feed tray can be cut to the specified size by the cutting unit and fed to the transfer unit. There is no need to provide an oval-sized paper feed tray inside the printer, and the number of paper feed trays can be reduced.

In the color image forming apparatus of the present invention, a paper feed tray for large-size transfer materials such as A3 and B4 is set in the apparatus main body, and key input by an operator and image information (size information) are performed. When a small-size transfer material such as A4 or B5 is designated, the large-size transfer material such as A3 or B4 fed from the paper feed tray is cut into half the size of A4 or B5 at the cutting section. It can be cut and fed to the transfer section, and the second half of the cut transfer material can be grip
Held in the paper discharge tray while grip over roller pair, when the paper size that retained is designated again, the grip
Rotate the roller pair in the opposite direction to set the rear half of the transfer material to the output tray.
To the transfer section via guide means
It is possible to, it is not necessary to provide a sheet feeding tray oval size such as A4, B5 in the apparatus main body, it is possible to reduce the paper feed tray number, and it is possible to eliminate waste of paper.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic configuration diagram of a color image forming apparatus showing one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a charging charger, 2 denotes a photosensitive drum, and 3 denotes a laser light source 3.
a, a rotating polygonal mirror 3b, and an optical writing unit including a scanning optical system (not shown) such as an fθ lens, on the photosensitive drum in accordance with an image signal for each color separation from an image reading unit or an image signal input unit (not shown). Is irradiated with laser light r to perform optical writing. Reference numeral 4 denotes a developing device having four developing units 4A, 4B, 4C, and 4D containing yellow (Y), magenta (M), cyan (C), and black (BK) toners. Is a cleaning device, 7 is a paper feed roller (paper feed roller), 8 is a pair of registration rollers, 9 is a transfer material (transfer paper), 10 is a transfer charger, 11 is a separation charger, 12 is a fixing roller 12a, and a pressure roller 1
2 is a fixing device composed of 2b or the like, 13 is a paper discharge roller (paper discharge roller), 14 is a spiral cutter of a cutting part, 15 is a fixed blade of a cutting part, 16 is a guide claw, 17 is a grip roller pair,
Reference numeral 8 denotes a paper discharge tray.

Here, an image forming method in the color image forming apparatus having the configuration shown in FIG. 1 will be described. In FIG. 1, the photosensitive drum 2 is first uniformly charged by the charging charger 1 and then, for example, black (B
Scanning exposure according to the image signal of K) is performed to form a negative electrostatic latent image. Then, the electrostatic latent image is developed by a black developing device (containing black toner) 4D of the developing device 4 to form a black (BK) toner image on the photosensitive drum 2. At this time, Y, M, C other than black (BK) of the developing device 4
The developing devices 4A, 4B and 4C are placed in a state where the toner does not fly, that is, in a state where they are separated from the photosensitive drum 2 by a moving mechanism (not shown). Then, the photosensitive drum 2 is charged by the charge removing charger 5, and black (B) on the photosensitive drum is charged.
The electrostatic latent image of K) is discharged. At this time, the cleaning device 6 is placed away from the photosensitive drum 2 by a moving mechanism (not shown).

Next, the electrophotographic process of charging, exposing, developing, and removing electricity is repeated by a method similar to the method of forming a black (BK) toner image, and yellow (Y), magenta ( M) and cyan (C) toner images are superimposed and formed. Then, after all the toner images are formed,
The transfer material 9 that has been fed and conveyed in advance by the feed roller 7 and is waiting at the registration roller pair 8 is fed to the transfer portion, which is the position where the photosensitive drum 2 and the transfer charger 10 are opposed to each other. The image is electrostatically transferred to the transfer material 9. Then, the transfer material 9 on which the toner image is electrostatically transferred is separated from the photosensitive drum 2 by the separation charger 11 and sent to the fixing device 12, where the toner image is formed by the fixing roller 12a and the pressure roller 12b of the fixing device 12. The transfer material is heated and pressurized and fixed to the transfer material, and the transferred transfer material after the fixing is discharged outside the apparatus by paper discharge rollers 13. On the other hand, after the electrostatic transfer, the cleaning device 6 is pressed against the photosensitive drum 2, and the toner remaining on the photosensitive drum 2 is removed by the cleaning device 6. Then, the residual charge on the photosensitive drum 2 is transferred to the charge removing charger 5.
As a result, the charge is removed, and the apparatus enters a standby state for the next image forming operation. Thus, one cycle of the color image formation is completed.

In the color image forming apparatus shown in FIG. 1, large-format paper (for example, A3, B4 size paper, etc.) is used.
Is set, and the transfer material 9 fed from the large-size paper feed tray is designated by an operator's key input or image information (size information). If the size of the transfer material is oval paper, it is cut to a predetermined size by the spiral cutter 14 and the fixed blade 15 of the cutting portion provided in the middle of the feeding path, and the front side of the cut transfer material is a pair of registration rollers 8. to be fed, the remainder of the transfer material rear guided downward by the guide claws 16, is discharged by the grip rollers 17, Ru is discharged onto the discharge tray 18. Here, when the large-size paper is, for example, A3, B4 size paper and the designated size is A4, B5, A3, B4
Is cut in half to obtain oval paper of A4 and B5 sizes. Therefore, in this case, the second half (A4 or B5) of the transfer material cut in half is held on the paper discharge tray 18 with the rear end gripped by the grip roller pair 17. Then, when the holding image information of the transfer material rear half portion of the same determine the size used was onto the discharge tray 18 is inputted, the transfer material latter part is Ru is conveyed by the gripping roller pair 17 to the registration roller pair 8.

Here, FIG. 2 is a schematic diagram showing the main components of the transfer material cutting unit and the paper discharge and re-conveyance unit at the rear of the transfer material of the color image forming apparatus shown in FIG. Normally, the spiral cutter 14 and the fixed blade 15 in the cutting section are separated from each other, and when the specified size is a large-sized paper on the paper feed tray, the transport is not hindered. And the second
As an operation 1, when the designated size is oval paper, when cutting the transfer material 9 fed from the feed roller 7, the fixed blade 1
5 moves in the direction A in the figure, and cuts the transfer material 9 at a predetermined position. After cutting, the fixed blade 15 moves to the initial position below.
Then, the cut transfer material front portion 21 is conveyed to the transfer portion by the registration roller pair 8 as it is. In addition, fixed blade 1
5 moves in the direction A at the same time as the guide claw 16 rotates in the direction B in the drawing, guides the leading end of the transfer material rear part 20 to the lower conveying path in the figure, sends it to the pair of grip rollers 17, and places it on the discharge tray 18. you discharged.

As a second operation, when the large-size paper (A3, B4, etc.) is cut in half as described above, the second half (A4, B5, etc.) of the transfer material 20 is moved to the guide claw 16 in the same manner as described above.
, And is held by the grip roller pair 17. The holding timing at this time is such that the grip sensor 19 provided on the upstream side of the grip roller pair 17 detects the rear end of the rear half portion 20 of the transfer material, and the rotation of the grip roller pair 17 stops after a predetermined time. By doing so, the rear end of the transfer material rear half 20 can be held by the grip roller pair 17. The front end side of the held transfer material rear half 20 is held by the paper discharge tray 18. Next, the transfer material rear half 20 held by the grip roller pair 17 is
By rotating the grip roller pair 17 in the opposite direction ( D direction in the drawing ) and rotating the guide claw 16 in the B direction in the drawing, the leading end of the second half of the transfer material is guided, and is transferred to the registration roller pair 8 for transfer. can be fed into the part and that Do not.

Here, differences between the first operation and the second operation will be described. In the first operation , the grip roller pair 17 in FIG. 2 cannot rotate only in the direction C in the figure, and all the cut paper is discharged to the paper discharge tray 18. This is 1
This corresponds to a case where a plurality of types of small-sized transfer materials are obtained from various types of large-size transfer materials, and the rear portion of the cut transfer material may have an irregular size after cutting. On the other hand, in the second operation , large-size paper such as A3 and B4 is cut in half and used as small-size paper such as A4 and B5. Can be used as oval paper. For this reason, if the latter half portion 20 of the cut transfer material is supported on the paper discharge tray 18 while being held by the grip roller pair 17, the grip roller pair 17 is moved in the D direction (reverse direction) when the size is used. , The second half of the transfer material 20 can be transported to the registration roller pair 8 via the guide claws 16, and the second half of the transfer material 20
Can be used as it is as an oval size transfer material.

[0015]

As described above with reference to the embodiment, in the color image forming apparatus of the present invention, only a large-sized transfer material (transfer paper) is set in the paper feed tray of the apparatus main body. When an oval-size transfer material is specified according to an operator's key input or image information (size information), the large-size transfer material fed from the paper feed tray is cut into a specified size by a cutting unit. The paper feeding tray, it is not necessary to provide an oval-sized paper feeding tray in the apparatus main body, and the number of paper feeding trays can be reduced, so that the image forming apparatus can be downsized. .

In the color image forming apparatus of the present invention, a paper feed tray for a large-size transfer material such as A3 or B4 is set in the apparatus main body, and key input by an operator and image information (size information) are performed. When a small-size transfer material such as A4 or B5 is designated in accordance with the above, a large-size transfer material such as A3 or B4 fed from the paper feed tray is cut in half by A4 or B5 or the like at the cutting section. It can be cut to size and fed to the transfer section, and the second half of the cut transfer material is gripped
Hold it on the output tray with the roller pair gripped,
When the held paper size is specified again, grid
Rotate the pair of rollers in the opposite direction and set the
From the b and transported to the transfer section via the guide
Since it is possible to feed the paper, it is not necessary to provide a paper tray of an oval size such as A4 or B5 in the apparatus main body, and the number of paper feed trays can be reduced, so that the image forming apparatus can be downsized. In addition, since the cut second half of the transfer material can be used, waste of the transfer material can be reduced, and resource saving can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a color image forming apparatus showing one embodiment of the present invention.

FIG. 2 is a schematic main part configuration diagram showing each mechanism of a transfer material cutting unit and a paper discharge and re-conveyance unit of a second half of the transfer material of the color image forming apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Charging charger 2 ... Photoreceptor drum 3 ... Optical writing unit 3a ... Laser light source 3b ... Rotating polygon mirror 4 ... Developing device 4A ... Yellow (Y) developing device 4B ... Magenta (M) developing device 4C ... Cyan (C) developing device 4D ... Black (BK) developing device 5 ... Charge removing charger 6 ... Cleaning device 7 ... 8: registration roller pair 9: transfer material (transfer paper) 10: transfer charger 11: separation charger 12: fixing device 12a: fixing roller 12b: pressurization Roller 13: Discharge roller (discharge roller) 14: Spiral cutter at cutting section 15: Fixed blade at cutting section 16: Guide claw 17: Grip roller pair 18: Discharge Tray 19: Gripsen 20 ... the transfer material rear half portion 21 ... transfer material first half of

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoaki Arai 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Naoki Matsuyama 1-3-6 Nakamagome, Ota-ku, Tokyo Examiner Kazuo Sekiya in Ricoh Company, Limited (56) References JP-A-59-194944 (JP, A) (58) Field investigated (Int. Cl. ⁷ , DB name) G03G 15/00 518

Claims (1)

(57) [Claims] 1. An electrophotographic image forming method comprising: irradiating a uniformly charged photoconductor with a laser beam to form an electrostatic latent image; and developing the electrostatic latent image to form a toner image. toner images of plural colors on the photosensitive member was synthesized by repeating, a color image forming apparatus for forming a color image synthesized toner image is transferred onto the transfer material to transfer the toner image on the photoreceptor Means for cutting the transfer material, means for feeding the front part of the cut transfer material to the transfer part, guide means for guiding the rear part of the cut transfer material in a direction different from the transfer part, and the like.
Means for stocking the rear of the guided transfer material
Means for stocking the rear part of the transfer material in a color image forming apparatus
Stock the back of the transfer material with a pair of efficient grip rollers
It consists of a paper output tray and is a transfer unit that transfers the toner image on the photoconductor
Copying materials from large-size transfer materials (A3, B4, etc.)
When cutting into small size transfer materials (A4, B5, etc.)
Feeds the first half of the cut transfer material to the transfer unit,
The latter half of the cut transfer material is discharged by the guide means.
Transfer to paper tray and transfer to paper tray
Grip the rear end of the rear half of the material with the pair of grip rollers.
Holding the transfer material
When sending the second half to the transfer unit again,
Rotate the roller pair in the opposite direction and move the
To the transfer section via the guide means.
Color image forming apparatus characterized by that.