JP2760359B2 - Color recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a color recording apparatus that performs color recording of at least two colors using an electrophotographic recording method or the like, and adjusts the position of an image writing unit with respect to an image carrier such as a photosensitive drum. An object of the present invention is to provide a color recording apparatus capable of correcting a deviation of a tilt position of a transferred toner image with respect to a main scanning direction without forming a charged toner image of different colors, and a toner recording unit. A transfer medium transport means provided for sequentially passing the transfer medium through the toner recording unit so that the charged toner images formed in step 1 are successively transferred onto the transfer medium and superimposed on each other. Along with being arranged in series along the transfer direction of the transfer medium,
The recording medium includes guide means provided on the side opposite to the toner recording unit for supporting the transfer medium and guiding its movement, the guide means is swingably held in a plane not including the transfer direction of the transfer medium, and is optional. The color recording apparatus is characterized in that it can be positioned at the swing position.

[Industrial applications]

The present invention relates to a color recording apparatus that performs color recording of at least two colors using an electrophotographic recording method or the like.

In the electrophotographic recording method, a uniform charged area is provided to an electrostatic latent image carrier such as a photosensitive drum, and an electrostatic latent image is formed on the charged area by optical exposure means, and the electrostatic latent image is charged. The toner image is developed with a toner to form a visible image, and a recording medium such as recording paper is applied to the charged toner image, and a charge having a polarity opposite to that of the charged toner is applied to the recording medium from the back surface of the charged toner image. The transfer toner image is electrically transferred to the recording medium side, and the recording medium having the transferred toner image is sent to, for example, a thermal fixing device, and the transferred toner image is heat-fixed to the recording medium. Is obtained.

When color recording is performed using such an electrophotographic recording technique, for example, as disclosed in JP-A-53-74036 and JP-A-53-96838, At least two toner recording units constituting a toner recording apparatus are arranged in series, and charged toner images of different colors are formed by these toner recording units. These charged toner images are transferred and superimposed on recording paper sequentially passed through the toner recording unit,
Thereafter, the recording medium is heat-fixed by, for example, a heat fixing device, whereby color recording with at least two or more types of colored toners is obtained.

As described above, in a color recording apparatus using an electrophotographic recording method, since colored toner images of different colors are superimposed on a recording medium, two or more colors are required to obtain a high-quality output color image. The superposition of the charged toner images must be performed accurately.

[Conventional technology]

Referring to FIG. 5, there is shown a conventional color printing apparatus configured to perform full-color printing. The color recording apparatus includes a transfer medium conveying means for conveying a transfer medium such as recording paper, that is, a recording paper conveyance belt assembly 10, and the recording paper conveyance belt assembly 10 is provided between a paper feeding unit 12 and a heat fixing unit 14. Placed in Four toner recording units 16Y, 16M, 16C and 16K are arranged in series on the upper side of the recording paper transport belt assembly 10, and these toner recording units have a configuration warmed to each other. The color of the developer (so-called toner) used is different.
That is, the toner recording units 16Y, 16M, 16C and 16K
Uses yellow toner, magenta toner, cyan toner, and black toner, respectively.

The recording paper transport belt assembly 10 includes a driven roller 10a disposed on the paper supply unit 12 side, a driving roller 10b disposed on the heat fixing unit 14 side, and an endless belt 1 wrapped between these two rollers.
0c, and three supporting and guiding rollers 10d arranged between the toner recording units 16Y, 16M, 16C and 16K to support the upper running portion of the endless belt 10c from the back side and guide the running. Consists of The driving roller 10b is driven to rotate counterclockwise in FIG. 5, so that the upper running portion of the endless belt 10c runs from right to left. The paper feed unit 12 includes a recording paper tray 12a for holding a stack of recording paper, a feeding roller 12b for feeding out the recording paper one by one from the stack, and an endless belt for feeding the recording paper fed by the feeding roller 12b. 1
A pair of guide rollers for feeding the upper traveling part side of 0c
10c. As shown in FIG. 5, the driven roller 1
On the 0a side, for example, a charger 18 configured as a corona discharger
The charger 18 applies a charge of an appropriate polarity to the upper traveling portion of the endless belt 10c. Therefore, the recording paper fed from the paper supply unit 12 to the upper traveling portion side of the endless belt 10c is held there by electrostatic attraction, and the four toner recording units 16Y, 16M, 16C and 1
6K is passed sequentially.

As described above, the toner recording units 16Y, 16M, 16C
Since 16K and 16K have the same configuration, only the configuration of the toner recording unit 16Y will be described below, and the description will be used for the other toner recording units 16M, 16C, and 16K. The toner recording unit 16Y includes a photosensitive drum 16a as an electrostatic latent image carrier, and the photosensitive drum 16a rotates clockwise (fifth
(In the figure). Around the photosensitive drum 16a, a charger 16b, an optical exposure unit 16c, a toner developing unit 16d, a transfer / removal unit 16e, and a cleaner 16f are sequentially arranged along the rotation direction. The charger 16b is composed of, for example, a corona discharger, and a uniform charging area is formed on the photosensitive drum 16a by the corona discharger. The optical exposure means 16c is composed of, for example, an LED array composed of a large number of light emitting diode elements arranged on one line, and an electrostatic latent image is written on the charged area of the photosensitive drum 16a by this LED array. The electrostatic latent image written by the LED array 16c is developed by the toner developing unit 16d with charged toner (the color of which varies depending on the toner recording unit), whereby the electrostatic latent image is visualized as a charged toner image. . The transfer / static eliminator 16e is, for example, a pair of corona dischargers 16e ₁ and 1
6e ₂ and the corona discharger 16e ₁ as a transfer device
The corona charger 16e ₂ functions as a static eliminator. More particularly, the transfer device in the 16e _1, same DC current which gives the opposite polarity of the charge flows to the charged toner image on the recording paper is passed between the photosensitive drum 16a, thereby the charging toner image Is transferred to the recording paper side, while the static eliminator 16e ₂ is provided with an alternating current so as to remove the electric charge applied to the recording paper for transferring the charged toner image and reduce the amount of the electric charge. The recording paper is easily separated from the photosensitive drum 16a without being wound around the photosensitive drum 16a by electrostatic attraction. The residual toner remaining on the photosensitive drum 16a without being transferred to the recording paper is cleaned by the cleaner 16f. Further, the toner recording unit 16Y is provided with a sensor 16 for detecting the position of the recording paper transported by the recording paper transport mechanism 10.
The sensor 16g controls the writing timing of the electrostatic latent image by the LED array 16c (the photosensitive drum 16a is rotated at a constant speed, and the endless belt 10c is driven at a constant speed). Thus, the charged toner image can always be transferred to a predetermined position on the recording paper.

After the yellow charged toner image is transferred to the recording paper, the recording paper is sequentially passed through the toner recording units 16M, 16C and 16K, and as a result, the magenta charged toner image and the cyan charged The toner image and the black charged toner image are successively superimposed. The recording paper waiting for such a four-color charged toner image is then sent to a heat fixing unit 14, where the four-color charged toner image is thermally fixed on the recording paper, and then the recording paper is discharged onto a recording paper receiving tray 20. .

By the way, as described above, each toner recording unit 16
In Y, 16M, 16C and 16K, the writing timing of the electrostatic latent image by the LED array 16c is controlled by using the sensor 16g, whereby the charged toner image is always transferred to a predetermined position on the recording paper, and The color shift is prevented from occurring when the charged toner image is transferred. However,
The color misregistration problem of the transferred toner image is not solved only by controlling the writing timing of the electrostatic latent image. The problem arises. For example, as shown in FIG. 6, one line of the charged toner image TM formed on the photosensitive drum 16a of the toner recording unit 16M is aligned with a line parallel to the main scanning direction of another color toner image indicated by a broken line. When the charged toner image is inclined, the charged toner image is transferred onto the recording paper in a state of being inclined with respect to the main scanning direction of the toner image of another color. That is, on the recording paper P shown in FIG. 6, the main scanning direction of the transfer toner images Y, C, and K for one line each of yellow, cyan, and black is relative to the sub-scanning direction (recording paper transport direction). While being substantially vertical and each being transferred parallel to each other, only the magenta transfer toner image M is inclined with respect to a line parallel to the main scanning direction of the other color toner images indicated by the broken lines. As a result, the magenta transfer toner image causes a color shift with respect to the transfer toner images of other colors. Such a color shift problem is caused by a recording paper transport system,
This is due to the relative mounting accuracy between the photosensitive drum 16a and the LED array 16c, and can be said to be an inevitable problem in the process of manufacturing a color recording apparatus.

Therefore, conventionally, as shown in FIG. 7, the LED array 16c of each of the toner recording units 16Y, 16M, 16C, and 16K is rotatable about a vertical axis X at the center thereof. The writing position of the electrostatic latent image with respect to 16a can be adjusted. That is, the sixth
As shown in the figure, for example, one line of the charged toner image TM formed on the photosensitive drum 16a of the toner recording unit 16M
Is inclined with respect to the main scanning direction, the transfer toner image M on the recording paper P is corrected to a position in the main scanning direction indicated by a broken line by rotating the LED array 16c about the vertical axis X. Will be able to do it.

[Problems to be solved by the invention]

However, in order to solve the color misregistration problem due to the rotational displacement of the LED array 16, there is a problem in that the support mechanism must have a degree of freedom for adjustment, which is complicated. In particular, when a laser beam is used as the optical exposure means, the scanning optical system itself is complicated, so that the support mechanism is considerably complicated. As a result of the adjustment of the optical exposure means, the writing direction (main scanning direction) of the electrostatic latent image may have to be largely inclined with respect to the center axis of the photosensitive drum. Due to the curvature of the photosensitive surface, the optical path length is not constant over the main scanning direction, and there is also a problem that the focus is not focused at both ends or the center.

Therefore, an object of the present invention is to provide a color recording apparatus of the type described above in which an image writing means such as an optical exposure means is transferred in the main scanning direction without adjusting the position with respect to an image carrier such as a photosensitive drum. An object of the present invention is to provide a color recording apparatus capable of correcting a deviation of a tilt position of a toner image.

[Means for solving the problem]

The difference in color recording according to the present invention is that at least two toner recording units for forming charged toner images of different colors from each other and the transfer of the charged toner images formed by these toner recording units onto a transfer medium one after another and superimposing them. Transfer medium transport means provided for sequentially passing the medium through the toner recording unit. According to the present invention, the toner recording units are arranged in series along the transport direction of the transfer medium, and the guide provided on the side opposite to the toner recording unit to support the transfer medium and guide its traveling. The guide means is swingably held in a plane not including the transfer direction of the transfer medium and can be positioned at any swing position.

[Action]

As is apparent from the above configuration, in the color recording apparatus according to the present invention, the supporting and guiding roller swings in a plane perpendicular to the recording paper conveyance direction on the recording paper introduction side of each toner recording unit. Since it is freely held and can be positioned at any swing position, the recording paper transport path length on both sides in the running direction of the endless belt can be adjusted,
For this reason, it is possible to make the main scanning directions of the transfer toner images coincide with each other when transferring the charged toner images.

〔Example〕

Next, an embodiment of a color recording apparatus according to the present invention will be described with reference to FIGS.

The color recording apparatus according to the present invention uses a recording paper transport belt assembly as shown in FIGS. 1 and 2 instead of the recording paper transport belt assembly 10 of the conventional color recording apparatus shown in FIG. can get. In other words, the paper supply unit 12, the heat fixing unit 14, the toner recording units 16Y, 16M, 16C and 16K, the charging unit 18 and the recording paper receiving tray 20 described with reference to FIG. Is a constituent element of Therefore, descriptions of those components will be referred to those of the color printing apparatus according to the present invention.

Referring first to FIG. 1, a transfer medium transport means or recording paper transport belt assembly constructed in accordance with the present invention is indicated generally by the reference numeral 22, and this recording transport belt assembly 22 is also shown in FIG. Conventional recording paper transport belt assembly 10
Similarly to the above, the driven roller 22a disposed on the paper supply unit 12 side, the drive roller 22b disposed on the heat fixing unit 14 side, and the endless belt 22c stretched between these two rollers are included. In addition,
The driving direction of the driving roller 22b is the same as in the case of FIG. According to the present invention, the recording paper transport belt assembly 22 further includes four support and guide rollers 22d that support the upper traveling portion of the endless belt 22c from the back side and guide the traveling thereof. The rollers 22d are arranged on the recording paper introduction sides of the toner recording units 16Y, 16M, 16C and 16K, respectively. Further, according to the present invention, each support and guide roller 22d is swingably held in a plane perpendicular to the recording paper conveyance direction and is freely positionable at any swing position, and a supporting structure therefor. Are shown in FIGS. 2 (a) and 2 (b).

As shown in FIGS. 2 (a) and 2 (b), the supporting structure of the supporting and guiding roller 22d includes a supporting substrate 24. The supporting substrate 24 is moved downward and upward in the endless belt 22c. It is arranged between the parts. The support structure of the support and guide roller 22d further includes an upright piece 24 that rises from the center of the support substrate 24.
a comprises a pivot member 26 pivotally mounted with a pivot pin 24b, which is preferably symmetrical with respect to the pivot pin 24b. Bearings 26a are provided at both ends of the swing member 26, and the support and guide roller 22d is rotatably held by the bearings 26a. The support substrate 24 is installed so that the axis of the pivot pin 24b coincides with the recording paper transport direction, so that the support and guide roller 22d is held swingably in a plane perpendicular to the recording paper transport direction. Will be. As shown in FIGS. 2 (a) and 2 (b), a compression coil spring element 28 is connected between one end of the swing member 26 and the support substrate 24, whereby the swing member 26 2 (a) and 2 (b), it is always elastically biased clockwise. On the other hand, a bolt element 30 is mounted on the other end side of the swing member 26 so as to be freely screwable, and the tip end thereof is brought into contact with the support substrate 24. Therefore, by swinging the bolt element 30, the swing member 26 can be positioned at an arbitrary swing position. That is, in FIG. 2 (a), the swing member 26 is placed in the horizontal position,
When the bolt element 30 is screwed in, for example, as shown in FIG. 2 (b), the swing member 26 assumes a position that has been swung counterclockwise.

By using the recording paper transport belt assembly 22 as described above, it is possible to correct the inclination position deviation of the transfer toner image in the main scanning direction without adjusting the position of the LED array 16c with respect to the photosensitive drum. Become. For example, the sixth
A specific description will be given of a case where the inclination position deviation of the charged toner image TM formed by the toner recording unit 16M is corrected as shown in the drawing.The support / guide roller disposed on the recording paper introduction side of the toner recording unit 16M will be described. 22d is the first
The recording paper is conveyed between the toner recording unit 16Y and the toner recording unit 16M at both sides in the running direction of the endless belt 22c between the toner recording unit 16Y and the toner recording unit 16M at this time. The path length will be different. That is, the recording sheet conveying path length represented by L ₁ is longer than the recording paper conveying path length represented by L _2, resulting recording paper is introduced into the toner recording unit 16M in a somewhat inclined state,
The inclination position shift of the charged toner image TM can be corrected. Needless to say, the amount of inclination of the supporting and guiding roller 22d is determined according to the amount of deviation of the inclined position of the charged toner image TM. On the other hand, the supporting and guiding roller 22d disposed on the recording paper introduction side of the toner recording unit 16C is supported and guiding roller 2d disposed on the recording paper introducing side of the toner recording unit 16M.
Since the recording paper is returned to its original state and introduced into the toner recording unit 16C, the charged toner image formed thereby may be displaced. Instead of being recorded or transferred to paper. Thus, as shown in FIG. 1, on the recording paper P, transfer toner images Y, M, C, and K for one line each of yellow, magenta, cyan, and black are obtained in the main scanning direction. become.

Referring to FIG. 3, there is shown another embodiment of the color recording apparatus according to the present invention, in which an intermediate transfer belt assembly 50 is used as a transfer medium conveying means. The intermediate transfer belt assembly 50 includes three rollers 51, 52, and 53, and an intermediate transfer belt 54 stretched over these three rollers. The intermediate transfer belt 54 is driven to travel in the direction of arrow X. . The support and guide roller described with reference to FIGS. 1 and 2 is provided on the upper traveling portion side of the intermediate transfer belt.
22d is provided. The toner images formed by the toner recording units 16Y, 16M, 16C, and 16K are temporarily transferred to the intermediate transfer belt 54, superimposed, and then transferred onto recording paper. That is, transfer to the roller 51 of the intermediate transfer belt 54 / discharger 16e similar transcription / discharger (in FIG. 3, the transfer device is in 16e _3, also discharger is represented by 16e ₄₎ is provided, The toner image is transferred from the intermediate transfer belt 54 onto the recording paper fed from the paper supply unit 12. In FIG. 3, reference numeral 100 denotes a transport belt for transporting the recording paper having the transferred toner image to the thermal fixing device 14. Also in this embodiment, it is needless to say that the inclination position deviation of the charged toner image can be corrected by adjusting the amount of inclination of the supporting and guiding roller 22d.

In the embodiment shown in FIG. 4, a continuous folding recording paper P 'is used as a transfer medium, and the continuous folding recording paper P' is composed of a pair of feed rollers 60, a heat roller 14a of the heat fixing device 14, and a backup roller. 14b and toner recording unit 1
Passed sequentially through 6Y, 16M, 16C and 16K. While the continuous folding recording paper P 'is running, it is guided and supported by the supporting and guiding roller 22d described with reference to FIGS. 1 and 2, and the inclination position of the charged toner image is corrected by adjusting the inclination amount. What can be done is the same as in the above embodiment.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, by providing a tiltable support and guide roller on the recording paper introduction side of each toner recording unit, the position of the charged toner image in the main scanning direction can be adjusted. However, it is not necessary to incorporate a complicated and expensive adjusting mechanism into the optical exposure means as in the prior art.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a recording paper transport belt assembly used in a color recording apparatus according to the present invention, FIG. 2 (a) and FIG.
FIG. 3B is a partial cross-sectional view showing in detail a support structure of the support and guide roller of the recording paper transport belt assembly shown in FIG. 1, and FIG. 3 is a schematic view showing another embodiment of the color recording apparatus according to the present invention. FIG. 4 is a schematic view showing still another embodiment of the color printing apparatus according to the present invention, FIG. 5 is a schematic view showing a conventional color printing apparatus, and FIG. 6 is a schematic view showing the conventional color printing apparatus shown in FIG. FIG. 7 is a perspective view similar to FIG. 4, showing a conventional example of correcting a tilt position shift of a charged toner image with respect to the main scanning direction. It is. 10: Conventional recording paper transport belt assembly, 12: Paper feed unit,
14: Thermal fixing unit, 16Y / 16M / 16C / 16K: Toner recording unit, 18: Charger, 20: Recording paper tray, 22:
... the recording paper transport belt assembly of the present invention, 22a ... follower roller, 22b ... drive roller, 22c ... endless belt, 22d ...
Support and guide roller, 24 ... Support substrate, 26 ... Swing member,
28: Compression coil spring element, 30: Bolt element.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-178979 (JP, A) JP-A-1-274164 (JP, A) JP-A-63-73276 (JP, A) 107280 (JP, U) Actually open 1988-76847 (JP, U) Actually open 1987-103557 (JP, U)

Claims (1)

(57) [Claims] At least two toner recording units (16Y, 16M, 16M) for forming charged toner images of different colors from each other.
C, 16K), and a transfer medium transport means provided for sequentially passing the transfer medium through the toner recording unit so that the charged toner images formed by the toner recording units are successively transferred onto the transfer medium and superimposed thereon. 22), wherein the toner recording units are arranged in series along the transfer direction of the transfer medium, and the toner recording unit is configured to support the transfer medium and guide its traveling. Guide means (22d) provided on the opposite side of the transfer medium, the guide means (22d) is swingably held in a plane not including the transfer direction of the transfer medium, and can be positioned at any swing position. A color recording apparatus characterized in that: