JPH08185077A - Image forming device - Google Patents

Abstract

PURPOSE: To prevent a deterioration in image quality caused by the repelling of ink at the time of forming an ink image due to offset preventing oil stuck at the time of fixing a toner image. CONSTITUTION: An electrophotographic system first image forming means 10 for forming a black-and-white toner image is disposed on the upstream side in the carrying direction (the direction of the arrow K1) of a recording material and an ink jet system second image forming means 20 for forming a color ink image is disposed on the downstream side. As the fixing unit of the second image forming means 20, an electronic flash fixing unit 18 is used. It is arranged in a state noncontact with the recording material P and fixes the toner image thereon with heat energy. It is unnecessary to use the offset preventing oil, so that even if the ink image is formed after the toner image is fixed, the ink can not be repelled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a plurality of image forming means of different image forming systems.

[0002]

2. Description of the Related Art Among image forming apparatuses such as copying machines and laser beam printers, there has been proposed an image forming apparatus having a plurality of image forming means having different image forming methods. For example, the electrophotographic first image forming unit is provided on the upstream side in the transport direction of a recording medium (hereinafter referred to as “recording material”) to form a black and white toner image on the recording material.
A second ink jet type image forming means is disposed on the downstream side, and a color ink image is formed on the same recording material after toner image formation.

With the above arrangement, a black and white image having a high image forming frequency can be formed at a high quality and a high speed by the electrophotographic system, while a color image having a low image forming frequency can be formed at a low cost by the ink jet system. You can

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus capable of favorably forming a toner image and an ink image on the same recording medium. Is.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the first invention is to provide an image along a conveyance path of a recording medium formed in the main body of an image forming apparatus. In an image forming apparatus having a plurality of image forming means of different forming methods, a first image forming means of an electrophotographic method, which is arranged on the upstream side in the conveying direction of the recording medium and forms a toner image on the recording medium, A second image forming unit of an ink jet system which is arranged on the downstream side in the transport direction of the recording medium and forms an ink image on the recording medium, and an image forming area on the recording medium by the first image forming unit. The image forming apparatus further comprises an identifying unit for identifying a first image forming area on which an image is formed and a second image forming area on which an image is formed by the second image forming unit, the first image forming unit including: Prior to the formation of the ink image by the second image forming means, there is provided non-oil fixing means for fixing the unfixed toner image adhered on the recording medium on the recording medium based on the output of the identifying means. .

In this case, the fixing means can perform the fixing by using the heat energy of the electronic flash.

A second aspect of the invention is an image forming apparatus having a plurality of image forming means of different image forming systems along a recording medium conveying path formed in the main body of the image forming apparatus, in the conveying direction of the recording medium. Second image forming means of an inkjet system which is arranged on the upstream side of the recording medium and forms an ink image on the recording medium, and an electronic which is arranged on the downstream side in the transport direction of the recording medium and forms a toner image on the recording medium. A first image forming unit of a photographic system and an image forming region on a recording medium are image-formed by the second image forming region and the first image forming unit which are image-formed by the second image forming unit. And a first image forming area for identifying the first image forming area.

In the first invention and the second invention, the first image forming area of the electrophotographic system can be a character area, and the second image forming area of the ink jet system can be a non-character area.

Finally, regardless of whether the above-mentioned ink removing means is a wiping means or a heating means, the second image forming means causes the recording means to eject ink to perform recording. Can be The recording means may include an electrothermal converter for generating thermal energy for ejecting ink, and the recording means uses the thermal energy applied by the electrothermal converter, The film may be ejected from the ejection port by utilizing the film boiling generated in the ink.

[0010]

According to the first aspect of the invention, based on the above construction, the first electrophotographic image forming means for forming a toner image disposed on the upstream side has the non-oil fixing means as the fixing means. The oil is not attached to the recording medium (recording material) during fixing. Therefore, even when an ink image is formed on the same recording medium on which the toner image is fixed by the second image forming means of the inkjet system arranged on the downstream side, the ink is repelled by the oil and the image quality is improved. There is no fear of a drop.

When the ink jet type image forming means is arranged on the upstream side and the electrophotographic image forming means is arranged on the downstream side as in the second aspect of the invention, the ink image is more than the toner image. Since the toner image is formed first, there is no possibility that the ink image is disturbed by the toner image fixing method using oil.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows a schematic diagram of an image forming apparatus according to the present invention, and FIG. 2 shows an image processing block diagram. Note that the image forming apparatus of the present embodiment records both of ink-jet recording (ink-jet type image formation) and electrophotographic recording (electro-photographic type image formation) on the same recording material, that is, “composite” or "Multiple" recording is possible. Here, the recording in which the ink image of the inkjet recording and the toner image of the electrophotographic recording do not overlap on the same recording material surface is referred to as “composite”, and the overlapping recording is referred to as “multiplex”.

The schematic structure of the image forming apparatus shown in FIG. 1 will be described. This is the first of the electrophotographic system for forming a black and white toner image on the upstream side in the conveying direction of the recording material P (direction of arrow K1). The first image forming unit 10 is provided, and the inkjet type image forming unit 20 that forms a color ink image is provided on the downstream side. Further, it has a feeding / conveying means 30 for the recording material P used for image formation, and an image reading section 50 for reading the image of the document D.

Next, the process of image formation will be described with reference to FIG.

First, a color document (hereinafter referred to simply as "document") D containing black characters is placed on the document table 51, and this document D is moved in the direction of arrow K2 through an optical system (not shown) including the light source 52. By doing so, the document surface D ₁ facing downward is scanned. The reflected light from the document D at this time is converted into RGB signals by the color sensor 101. An image processing circuit (identifying means) 53 based on the RGB signals.
A laser drive signal and an inkjet head drive signal are generated by the above.

Electrophotographic first image forming means 10
Includes a drum-shaped photoconductor (hereinafter referred to as “photosensitive drum”) 11 as an image carrier. The photosensitive drum 11 is
It is rotatably supported in the direction of arrow R11, and is surrounded by a charger 12, a laser unit (exposure means) 13, a developer 14, a transfer charger 15, in that order along the rotation direction.
A cleaning device 16 and a pre-exposure lamp 17 are arranged. The surface of the photosensitive drum 11 is a charger 12.
After being uniformly charged by the laser unit 13, the laser beam is irradiated by the laser unit 13. This laser light is emitted based on the laser drive signal generated by the image forming circuit 53. By this irradiation of laser light, an electrostatic latent image corresponding to the original image is formed on the surface of the photosensitive drum 11. This electrostatic latent image is made into a latent image as a toner image by the developer (toner) attached by the developing device 14.

The toner image formed on the photosensitive drum 11 is transferred onto the recording material P by the transfer device 15. The recording material P stored in the paper feed cassette 31 is transported to the transfer position where the photosensitive drum 11 and the transfer device 15 face each other via the pickup roller 32, the transport roller 33, and the like. . The residual toner on the surface of the photosensitive drum 11 after the toner image transfer is removed by the cleaning device 16, and unnecessary charges of the pre-exposure lamp 17 are removed, and the photosensitive drum 11 is used for the next image formation.

On the other hand, the recording material P after the transfer is carried to the flash fixing device (fixing device) 18 by the carrying roller 34 while carrying the unfixed toner image on the surface.
The flash fixing device 18 causes the electronic flash to emit light, and the energy of the flash fixing device 18 causes the recording material P to contactlessly.
The unfixed toner image above is fused and fixed on the surface to be fixed.

The recording material P having the toner image fixed thereon is conveyed by the guide roller 35 to the second image forming means 20 of the ink jet system, where the recording head 21 forms a color ink image. Recording head 2
1 is a head for four colors, that is, a black head 11
4, a cyan head 115, a magenta head 116, and a yellow head 117, which eject the inks of the respective colors and adhere them to the surface of the recording material P to form a full-color ink image of four colors. As a result, on the recording material P, a black and white toner image by the electrophotographic first image forming unit 10 and a color ink image toner image by the inkjet second image forming unit 20, a composite recording or a multiplex image recording. Will be recorded.

Next, referring to FIG. 2, the image processing circuit 53.
The image processing in will be described.

RG obtained by the color sensor 101
The B signal is a black character detection circuit 102 and a LOG conversion circuit 105.
And go to. The black character detection circuit 102 determines whether or not the read image is a black character and generates a black character print signal for the pixel determined to be a black character. The black character print signal is input to the laser controller 103, and a signal for forming an image of black character pixels by the first image forming unit 10 of the electrophotographic system is generated.

RGB input to the LOG conversion circuit 105
The signal is converted into a density signal and the masking UCR circuit 1
At 06, masking calculation and black component generation are performed, and print multi-valued data of each ink of black, cyan, magenta, and yellow is obtained. Next, the binarization circuit 107 performs binarization by the error diffusion method or the like.

The output signal of the black character detection circuit 102 is logically inverted by the inverter 104 and logically operated by the binarized output and the AND circuit 108. As a result, the black character pixels are recorded by the first image forming unit 10 of the electrophotographic system, and the pixels recorded by the first image forming unit 10 are printed by the second image forming unit 20 of the inkjet system. Will not be done. The output signal of the AND circuit 108 is converted into a parallel signal by the shift register 109 and input to the head drivers 110, 111, 112, 113, and the black head 114, cyan head 115,
The signals are input to the magenta head 116 and the yellow head 117 as drive signals. The second image forming unit 20 can form a four-color full-color ink image on the recording material P by these heads 114, 115, 116, 117.

The image forming apparatus having the above structure has the following effects.

First, it is possible to make the fixing unevenness caused by using the flash fixing device 18 inconspicuous.

In flash fixing, uneven fixing tends to occur due to the following two factors. First, it is not possible to obtain a uniform fixing energy distribution within the irradiation area in one emission of the electronic flash. Second one
When a toner image on one sheet of recording material P is divided and fixed several times, the energy distribution is not uniform at the joints between fixing regions, and fixing unevenness is likely to occur. In this case, in order to prevent the fixing unevenness at the joint between the fixing areas, the recording material P
It is also possible to apply energy to all areas at once.
However, for that purpose, the energy required for the electronic flash becomes large, which causes a large size of the image forming apparatus and a cost increase.

By the way, such unevenness is not noticeable in a character image. Therefore, in the case of a character image in which unevenness is not noticeable, there is no problem in practical use even when the fixing is performed by the flash method, which is likely to cause unevenness in fixing.

Further, when it is desired to clearly output an image in which a black character image and an intermediate image are mixed, the character image is output by the first image forming means 10 of the electrophotographic system, and the other area is the second of the ink jet system. It is effective to output by the image forming means 20. The reason is that the print pixels of the inkjet method vary in size, and the print position accuracy is generally inferior to that of electrophotography.Therefore, the electrophotographic method is suitable for outputting character images with many fine lines, which require severe print position accuracy. This is because inkjet is generally good in color reproducibility.

Secondly, since the flash fixing is non-contact with the toner on the recording material P, there is no possibility that the toner on the recording material P is offset to the flash fixing device 18 at the time of fixing, and the toner is offset at the time of fixing the toner image. No need to apply protective silicone oil. Therefore, it is possible to prevent the ink from being repelled by the silicone oil adhering to the recording material to deteriorate the image quality during inkjet recording after the toner image is fixed. That is, according to the first embodiment, since the non-contact flash fixing device 18 is used as the fixing device, it is not necessary to use the oil for toner offset prevention. Therefore, the electrophotographic method is used on the same recording material P. Even when a black-and-white toner image and a color ink image formed by an inkjet method are combined and recorded, it is possible to prevent the deterioration of image quality.

Thirdly, unlike the heating type fixing device, the flash fixing device 18 does not require a wait time at the time of fixing, so that the time until image output can be shortened. <Embodiment 2> FIG. 3 shows an overall schematic configuration diagram of an image forming apparatus of Embodiment 2.

In this embodiment, the ink jet type second image forming means 20 is arranged on the upstream side in the conveying direction of the recording material P, and the electrophotographic type first image forming means 10 is arranged on the downstream side. Are installed. Therefore, even when the electrophotographic first image forming unit 10 on the downstream side has the heating-type fixing device 19 and the silicone oil is used at the time of fixing, the inkjet method is used prior to the formation of the toner image. Since the second image forming unit 20 forms an ink image, there is no possibility that the ink is repelled by the silicone oil and an image defect occurs when the ink image is formed.

The image forming operation by image formation of this embodiment will be briefly described below.

A color original D containing a black character image is placed on the original table 51, and the original surface D ₁ of the original D is a light source 52.
The light is emitted by the laser beam, and scanning is performed by moving the optical system. At this time, the original image is the color sensor 10
1 to obtain an RGB signal. From this signal, the image processing circuit 53 (see FIG. 2) generates a laser drive signal and an inkjet head drive signal.

First, a color ink image is formed on the recording material P by the ink jet type second image forming means 20. That is, the recording material P is fed by the feeding / conveying means 3
It is sent out from the paper feed cassette 31 of No. 0 by the pickup roller 33, and is conveyed below the recording head 21 of the inkjet type second image forming unit 20 by the conveying roller 33. Here, four color heads, that is, the black head 114, the cyan head 115, the magenta head 116, and the yellow head 117 eject their respective inks to form a color ink image on the recording material P.

On the recording material P having a color ink image formed on its surface, a toner image is then composite-recorded or multiple-recorded. In the first electrophotographic image forming means 10, the laser drive signal provided by the image processing circuit 53 is input to the laser unit 13 to generate laser light, which has already been uniformly charged by the charger 12. The surface of the photosensitive drum 11 is irradiated. By the irradiation of the laser light, an electrostatic latent image corresponding to the character area of the original image is formed on the surface of the photosensitive drum 11. The electrostatic latent image on the photosensitive drum 11 is visualized as a toner image with toner attached by the developing device 14.

The toner image on the photosensitive drum 11 is transferred onto the recording material P by the charger 15. By this transfer, a black and white toner image is composite-recorded or multiple-recorded on the recording material P on the color ink image already formed by the second image forming unit 20.

In this way, the recording material P carrying the color ink image and the unfixed black and white toner image on the surface is
It is conveyed to the fixing unit 19 of the heating and pressing system. The fixing device 19 is
The recording material P has an upper fixing roller having a heater therein and a pressure roller pressed against the upper fixing roller from below, and nips and conveys the recording material P at a fixing nip portion therebetween, and at this time, the recording material P
Is heated and pressed to fix the unfixed toner image on the surface.

As a result, a color ink image and a black-and-white toner image toner image are composite-recorded or multiple-recorded on the same recording material P surface.

The image processing by the image processing circuit 53 is the same as that of the first embodiment described with reference to FIG.

According to the image forming apparatus having the above-described structure, since the fixing device 19 of the heating and pressurizing type is used as the fixing device, the power required for fixing is large and the wait time is long.
Compared with flash fixing, there is less fixing unevenness, and the effect of improving image quality is obtained.

When it is desired to clearly output an image in which a black character image and an intermediate image are mixed, the character area (first image forming area) is output by the electrophotographic image forming means 10 and other non-character areas are output. It is effective to output the (second image forming area) by the image forming means 20 of the inkjet system. The reason for this is that the print pixels of the inkjet method vary in size and the print position accuracy is generally inferior to that of the electrophotographic method. This is because inkjet is generally good in color reproducibility.

Secondly, since the toner image is formed by the electrophotographic method after the ink image is formed by the ink jet method, the ink is deteriorated by the image deterioration at the time of the ink image formation, that is, the silicone oil adhered at the time of the fixing by the electrophotographic method. It is possible to prevent deterioration in image quality due to being repelled.

As a result, the ink image of the ink jet system and the toner image of the electrophotographic system are the same recording material P.
Even if the composite recording or the multiple recording is performed, it is possible to prevent the deterioration of the image quality.

The present invention is particularly effective in a recording apparatus using an inkjet recording head for recording by forming flying droplets by utilizing thermal energy among the inkjet recording methods.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored, a rapid temperature rise corresponding to the recorded information and exceeding nucleate boiling is applied. , It is effective because it generates heat energy in the electrothermal converter and causes film boiling on the heat-acting surface of the recording head, resulting in the formation of bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis. Is. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, U.S. Pat. Nos. 4,558,333 and 44,596 disclosing a configuration in which a heat acting portion is arranged in a bending region.
The configuration using the specification No. 00 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the structure corresponding to the discharging portion is disclosed in Japanese Patent Laid-Open No. 59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the ink jet from the main body of the apparatus is electrically connected to the main body of the apparatus by being mounted on the main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add the ejection recovery means of the recording head, the preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specific examples thereof include preheating for heating the recording head by using a capping unit, a cleaning unit, a pressurizing or suctioning unit, an electrothermal converter or a heating element other than this, or a combination thereof. Means and preliminary ejection means for performing ejection different from recording can be mentioned.

Regarding the type or number of recording heads to be mounted, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode of only the mainstream color such as black, but it may be either a recording head is integrally formed or a combination of a plurality of recording heads is used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or to prevent the ink from evaporating, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, the ink is liquefied by applying heat energy according to the recording signal,
The present invention is also applicable to the case of using an ink that has a property of liquefying only when heat energy is applied, such as one that ejects liquid ink or one that already begins to solidify when it reaches a recording medium. In such a case, the ink is retained as a liquid or solid in the recesses or through holes of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, in addition to the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function can be used. It may be a form or the like.

[0053]

As described above, according to the first aspect of the invention, the fixing means of the electrophotographic first image forming means disposed on the upstream side is a non-oil fixing means.
Oil is not attached to the recording medium when the toner image on the recording material is fixed. Therefore, even if an ink image is formed on the same recording medium after the toner image is fixed, the ink is not repelled by the oil and the image quality is not deteriorated. Note that, as a non-oil fixing means, for example, there is one that uses heat energy by electronic flash.

According to the second aspect of the invention, the ink jet type image forming means is arranged on the upstream side and the electrophotographic image forming means is arranged on the downstream side, and the ink image is formed first and the toner image is formed later. It Therefore, even when oil is used for fixing the toner image, this does not disturb the ink image.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of a first image forming apparatus.

FIG. 2 is a block diagram showing image processing in the image forming apparatus.

FIG. 3 is an overall schematic configuration diagram of a second image forming apparatus.

[Explanation of symbols]

10 First Image Forming Means (Electrophotographic Image Forming Means) 11 Photosensitive Drum 12 Charging Device 13 Laser Unit 14 Developing Device 15 Transfer Charging Device 16 Cleaning Device 17 Pre-exposure Lamp 18 Fixing Means (Electronic Flash Fixing Device) 19 Fixing Means (heating type fixing device) 20 Second image forming means (ink jet type image forming apparatus) 21 Recording head 30 Feeding and feeding means 50 Image reading section 53 Identification means (image processing circuit) 101 Color sensor 114 Black head 115 Cyan Head 116 Magenta head 117 Yellow head D Document P Recording medium (recording material)

Claims (7)

[Claims] 1. An image forming apparatus having a plurality of image forming units of different image forming systems along a recording medium conveying path formed in an image forming apparatus main body, the upstream side in the conveying direction of the recording medium. A first electrophotographic image forming unit that is disposed and forms a toner image on a recording medium, and an inkjet type first image forming unit that is disposed downstream in the transport direction of the recording medium and forms an ink image on the recording medium. Two
Image forming unit, and a second image formed by the second image forming unit on the recording medium, the first image forming region formed by the first image forming unit, and the second image formed by the second image forming unit. Identification means for identifying a forming area, and the first image forming means attaches onto a recording medium based on the output of the identifying means before the ink image is formed by the second image forming means. An image forming apparatus comprising: a non-oil fixing unit that fixes the formed unfixed toner image on a recording medium. 2. The image forming apparatus according to claim 1, wherein the fixing unit performs fixing by using thermal energy of electronic flash. 3. An image forming apparatus having a plurality of image forming means of different image forming systems along a recording medium conveying path formed in the image forming apparatus main body, the upstream side in the conveying direction of the recording medium. Second type of inkjet system which is arranged and forms an ink image on a recording medium
The image forming means, the first image forming means of the electrophotographic system which is arranged on the downstream side in the conveying direction of the recording medium and forms a toner image on the recording medium, and the image forming area on the recording medium, A second image forming area imaged by the second image forming means and an identifying means for identifying the first image forming area imaged by the first image forming means. Image forming apparatus. 4. The first image forming area according to the electrophotographic method is a character area, and the second image forming area according to the inkjet method is a non-character area. The image forming apparatus according to any one of 3 above. 5. The image forming apparatus according to claim 1, wherein the second image forming unit is an inkjet system in which the recording unit ejects ink to perform recording. . 6. The image forming apparatus according to claim 5, wherein the recording unit includes an electrothermal converter for generating thermal energy for ejecting ink. 7. The recording means causes the ink to be ejected from the ejection port by utilizing film boiling generated in the ink by the thermal energy applied by the electrothermal converter. Image forming apparatus.