JP2000103121A - Image-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image-forming apparatus which can well correct a color shift caused by a distortion of an image hold body and can greatly reduce a pixel position shift of coloring material particles to a pixel position. SOLUTION: An image hold body 22 includes a plurality of unit pixel areas at a surface each having within a hole a coloring material adhesion part equipped with a strong adhesion force at a center, and a detection unit line in which a reflectance of one line is made different from a reflectance of the other unit lines. Each of three detecting parts 80a, 80b, 80c for detecting the detection unit line comprises a detection reference light-generating part 81a for irradiating light to the image hold body 22 and a reflecting light quantity- detecting part 81b for detecting light reflected at the surface of the image hold body 22. An amount of a curve of the surface of the image hold body is operated on the basis of a detection timing for the detection unit line detected by the detecting parts 80a, 80b, 80c with use of the image hold body 22, which is output as curved amount data.

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, and more particularly, to an image forming apparatus such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art Generally, an image forming apparatus is provided with a plurality of printing stations arranged in parallel, and a belt-like transfer material (web) is sequentially guided to each printing station by a conveying member such as a conveying roller. An image forming apparatus having a configuration in which a plurality of color material images are transferred in a superimposed manner at the predetermined position to obtain a color image, and thereafter, the web is individually cut off, and a plurality of printing stations arranged in parallel, A transfer material that has been cut to a predetermined size is mounted on a transport belt, and the transfer material is guided to each printing station in sequence with the movement of the transport belt, and a plurality of color material images are transferred onto the transfer material in a superimposed manner. 2. Description of the Related Art There is known an image forming apparatus configured to form a color image on each transfer material.

In the former image forming apparatus, for example, Japanese Patent Laid-Open No. 7-727 discloses a method for adjusting the transfer position of a color material image.
As described in Japanese Patent Publication No. 77, a rotary disk is fixed to a shaft of a photosensitive drum of a printing station, and an encoder is provided which outputs a signal when the rotary disk rotates by a predetermined amount. There has been proposed a configuration in which the delay unit executes the transfer of the color material image by the subsequent printing station.

As another configuration when using a web, as described in JP-A-7-72776, a web is attracted to the surface of a photosensitive drum by a corona device when a color material image is transferred. The transfer position of the color material image and the color material image are adjusted by adjusting the web so that the web is in contact with the photosensitive drum at a predetermined winding angle ω while applying a tensile force to the web. It has been proposed that the transfer position of the color material image is adjusted by preventing the occurrence of slip which occurs when transferring the color material.

In the image forming apparatus having the latter configuration, a pattern for detecting a color shift is formed on a color material image carrier of each printing station, and the pattern for detecting a color shift is superimposed, and the color shift is corrected based on the pattern. A configuration is known. Further, in Japanese Patent Application Laid-Open No. 10-20606, when correcting based on a color misregistration detection pattern, a color misregistration detection pattern is superimposed on a transfer material on a transport belt to perform color correction. It has been proposed to correct a color shift caused by an error between a color shift generated at the time of shift detection and a color shift generated at the time of image formation.

Japanese Patent Application Laid-Open No. Hei 7-261628 discloses a method in which a register mark for position detection is formed of a color material in a non-image forming area on a photosensitive drum together with image formation, and both sides of a conveying belt in the conveying direction are transferred together with image transfer. An image forming apparatus is described in which a register mark is transferred to a register mark, and an image forming position is detected from a position of the register mark obtained by detecting the register mark on the conveyor belt by a detecting means, and color shift correction is performed. I have.

[0007]

Generally, in an image forming apparatus, it is known that a color shift occurs due to a mechanical factor. For example, Japanese Patent Application Laid-Open No. 7-72777 described above.
In the image forming apparatus described in Japanese Patent Application Laid-Open No. 7-72776, the accuracy of detecting rotation fluctuation of the image carrier depends on the amount of eccentricity of the rotating disk fixed to the image carrier shaft. Therefore, when a rotating disk fixed to the image carrier shaft is used, it is necessary to separately provide a correction means for correcting a detection error based on the amount of eccentricity of the rotating disk, such as an auxiliary encoding module or a correction data storage IC. ,
It is disadvantageous in terms of machine size and cost.

In addition, even if these corrections are made, it is theoretically impossible to completely eliminate a detection error due to the eccentricity of the rotating disk due to a correction calculation accumulated error or the like, and the present invention is employed for applications requiring high detection accuracy. It is not possible.

On the other hand, in an image forming apparatus having a structure described in JP-A-10-20606 or JP-A-7-261628, a color material is used as a mark for detecting the amount of deformation of an image carrier after a mark latent image is formed. Since the register mark developed with the particles is used, (1) extra color material particles are consumed for forming the register mark, (2) it is necessary to remove unnecessary register marks, and (3) )
There is a drawback in that the coloring material particles provided as register marks scatter and contaminate the inside of the apparatus, which causes a new problem, and adversely affects other subsystems.

In general, in order to prevent the contact position of the web or the transfer belt with the photosensitive drum from shifting, the color material image on the photosensitive drum is transferred to the transfer material on the web or the transfer belt. Alternatively, a pressing force in the direction toward the photosensitive drum is exerted from the back side of the transport belt by a primary transfer unit such as a roller.

However, in this case, as shown in FIG.
A phenomenon occurs in which 0 is curved. Since this curvature is reflected on the transferred image, if the color material image is transferred to the transfer material 94 without considering the amount of curvature of the photosensitive drum 90 as shown in FIG. An image 100 that is distorted according to the amount of curvature of 90 is formed, which causes color misregistration.

As shown in FIG. 24, the color material supply section 24 is provided at a position opposite to the primary transfer means 26 with respect to the photosensitive drum 90 in order to prevent such color shift caused by the curvature of the photosensitive drum 90. A configuration is conceivable in which the photosensitive drum 90 is provided so as to oppose the pressing force of the primary transfer unit 26 to suppress the distortion of the photosensitive drum 90. However, in this case, since the opening of the coloring material supply unit 24 faces vertically downward, the coloring material is easily spilled from the opening, and the generation of image noise due to the spilled coloring material is inevitable.

In order to prevent color misregistration caused by the curving of the photosensitive drum, it is conceivable to detect the curving state of the photosensitive drum and correct the image data according to the curving state. In this case, at least two bending marks are formed at both ends and one center in the longitudinal direction of the photosensitive drum, and at least three marks are formed on the non-image forming area of the transfer material of the web or the conveyance belt or on the conveyance belt. A configuration is conceivable in which one mark is transferred, and the amount of curvature of the photosensitive drum is detected by detecting at least these three marks by the mark detection unit.

In this case, when manufacturing the photosensitive drum, it is necessary to previously form a plurality of curving detection marks at intervals along the longitudinal direction of the photosensitive drum by printing or the like. There is a drawback that the cost is high and the parts cost is increased.

In addition, the central portion in the longitudinal direction of the photosensitive drum is an image forming area, and when a curve detection mark is directly printed in the image forming amount area, the photosensitive characteristics of the printed mark portion and other portions are different. As a result, there is a disadvantage that an image having no defect cannot be formed.

As described above, the conventional technique has a problem that the latent image signal cannot be corrected based on the obtained information while continuously detecting the bending state of the photosensitive drum.

Further, in an image forming apparatus configured to perform multiple printing by transferring a large number of color material images to the same image area, images are transferred to the same image forming area using different photosensitive drums for each color. However, the color material images transferred in a different curved state for each photosensitive drum are superimposed on the same image forming area, and there is a problem that the amount of color misregistration cannot be irregularly predicted depending on the image.

By the way, in the conventional image forming process of the electrophotographic technique, several factors are overlapped, and a pixel position shift of the color material particles occurs.

The first factor is that the charge q held by the color material particles and the electrostatic force F = q applied by the electric field E applied between the photosensitive member and the developing electrode, the recording paper or the intermediate transfer member. The pixel position shift occurs when the color material particles are transferred to the target medium by E.

That is, it is known that the spatial electric field formed between the regular rectangular latent image on the photosensitive member and the developing electrode is as shown in FIG. (Journal of the Institute of Electrophotography 104
No.3, 1993). In FIG. 25, on the photoconductor, latent images having a uniform charge density of 100 μm width are formed at 100 μm intervals in the process direction.
Shows the isoelectric profile of the contrast potential when X is displaced from the center of the latent image in the process direction (photoconductor rotation direction) and Y is displaced in the direction of the target electrode (gap).

As shown in FIG. 25, the actual photosensitive member and the developing electrode are not perfectly parallel electrodes, but the lines of electric force are deflected with a curvature by the edge effect at the edge of the rectangular latent image. It turns out that it does not become completely parallel to the surface.

FIG. 26 shows the result of calculation of the contrast potential distribution along the Y direction in FIG. 25. The solid line a in FIG. 26 indicates the contrast potential at the center of the central latent image. The dotted line b is the contrast potential distribution at the intermediate position between the central latent image and the adjacent latent image, and the dashed line c is the contrast potential distribution at a position further 70 μm away from the outer edge of the outermost latent image.

These calculation results show that the maximum point of the contrast potential decreases as the distance from the center of the latent image increases in the process direction, and that the maximum point of the contrast potential shifts between the photosensitive member and the target electrode. In the actual developing process, development does not start at the central portion of the latent image (X = 0) shown in FIG. 25, but the effective electric field threshold in the developing nip portion (electric field of the photoconductor, color material charge, developing electrode bias) (Effective electric field threshold value to be determined), and as a result, it is equivalent to the development that the position of X in FIG. 25 is shifted and developed.

The color material particles are subjected to an electrostatic force for transferring and moving. However, the contrast potential is low and the color material particles are shifted from a predetermined position, so that the color material particles can be surely moved to a desired pixel position. become unable. This is an essential problem of electrophotography using static electricity.

For example, there are two well-known processes relating to the movement of the color material particles, a development process and a transfer process, and the variation in the position of the color material particles such as scattering of the color material, pre-transfer, and color material explosion, respectively. This is a major problem as an image defect.

For this reason, conventionally, the gap between the photosensitive member and the developing sleeve has been reduced as much as possible, and the use of conductive coloring material particles has substantially reduced the scattering of the coloring material by making the developing electrode substantially close to the developing electrode. By controlling the posture of the recording paper entering the transfer nip, removing the charged charges of the visible image formed on the photoreceptor, removing the color material image transferred to the recording medium again, etc. Measures are taken to reduce the variation in the positions of the color material particles.

The second factor of the pixel displacement is as follows.
Color shift and color registration resulting from rotation or movement accuracy (hereinafter referred to as motion quality) of a photoconductor, a transfer drum generally used in a copying machine or a printer, or a recording paper conveying belt are exemplified.

These occur as color misregistration in a low frequency band and as stripes in a regular process direction (hereinafter, referred to as banding) in a high frequency band. The color misregistration and banding caused by the poor motion quality appear as image defects in high-definition halftone reproduction or color character reproduction, and significantly degrade image quality.

For this reason, in conventional copiers and printers, in order to improve the motion quality of the photoconductor and the conveyor belt, control such as feedforward and feedback is performed, or the mechanical accuracy of components and assembly is improved. Is supported.

In addition, a change in light amount of the recording information writing device due to a change over time or an environmental change, particularly a change in temperature, a shift in a synchronous property in each mechanical configuration (for example, in a tandem-type copying machine or a printer, a transport belt Is adjusted so that the ratio between the diameter of the roll driving the roller and the distance between the photoconductor shafts becomes an integer. We need to deal with this problem.

This causes problems such as an increase in the size, complexity, and cost of the apparatus, and can be said to be the limit of the conventional electrophotographic technique as a recording technique that does not reduce the reliability.

In the printing technology field, in order to suppress the occurrence of the above-described pixel position shift, the repetition accuracy is increased by using a large amount of expensive high-precision parts. Basically, the same plate is used to prevent pixel misalignment in the image writing process such as electrophotography, and color printing of yellow, magenta, cyan, and black is performed from the plate cylinder to the blanket cylinder and recording paper. The printing phenomena inherent in printing inks, "Thixotropic properties", that printing is performed stably, plate cylinders and blanket cylinders,
The recording paper support / conveyor cylinder is driven by expensive precision gears that have both high reliability and durability, and pixel position deviation adjustment is performed by a specialized operator interactively performing pixel position deviation adjustment. Average value of 15 to 3 for high-quality printing
It is set at 0 μm. However, there remains a problem that it is unavoidable to increase the size and cost of the device, and it is difficult to respond to on-demand demands required for business and office use.

In order to solve such a problem, in recent years,
In CeBIT'96, an image forming apparatus (Oce'3125C Euro Color Copier) for visualizing a color material by bias development without using an electrostatic latent image by a photoconductor has been announced.

This image forming apparatus, as shown in FIG.
Drum 96K to yellow imaging drum 96
The image forming drums 96 are arranged in tandem to Y. Further, the developing rollers 97 of the corresponding colors are arranged on the individual imaging drums 96. The subscripts K, B,
R, G, M, C, and Y represent each color, and are represented by omitting the subscripts when representing them.

This imaging drum 96 is shown in FIG.
As shown in a partial cross-sectional view of FIG. 5, a ring-shaped electrode 98 is arranged at a resolution of 400 dpi in an axial direction in an insulating layer 88 whose surface is covered with a dielectric layer 86. A fixed electrode group (not shown) is provided in the imaging drum 96. The fixed electrodes are arranged in a matrix to transmit recording information from a slip ring (not shown).

The color material moves from the developing roll 97 to which an electric field is applied according to the recording information on the imaging drum 96 to form an image. The recording process starts from black development and has a single-layer structure of each of the seven colors from yellow to yellow. Color material images corresponding to the respective colors are formed on the imaging drum 96 sequentially. Next, the color materials of each color are transferred onto the intermediate transfer drum 86 without overlapping. Further, the recording paper 32 is conveyed from the paper supply tray 15 so as to match the leading end of the image on the intermediate transfer drum 86, and the image on the intermediate transfer drum 86 is transferred to the recording paper 32 by the secondary transfer roll 16. The sheet is discharged to the discharge tray 17.

In the image forming apparatus having this configuration, since the image is visualized by the bias development, the color misregistration caused by the mechanical factors as described above is effective, but is 63.5 μm.
Pixel alignment with respect to individual color material particles in a single pixel of (400 dpi) is not performed. for that reason,
The first problematic pixel displacement occurs at the same level as an image forming apparatus using an image forming process of the conventional electrophotographic technology.

As another image forming apparatus, Array is used.
A color material jet image forming apparatus represented by Printers AB is known. This color material jet image forming apparatus employs a direct recording technology that does not use a photoreceptor, and allows a non-magnetic one-component color / color material (black is a magnetic one-component color material) on a developing sleeve to fly directly onto recording paper. To form a color image.

That is, as shown in FIG. 29 (A), a two-dimensionally arranged mesh-like control electrode 76 is provided between the developing sleeve 74 and the recording paper 32, and one side is provided on the back of the recording paper 32. A back electrode 78 is provided, and 15 is provided between the developing sleeve 74 and the back electrode 78.
With the voltage of 00 V and the control electrode voltage (275 V during printing / 50 V during non-printing), the color material is caused to fly on the recording paper 32 according to the recording information, and an image is formed on the recording paper.
A tandem type color image sample was presented for the first time in NIP12 IS &T'96, but the resulting image has an image quality with remarkable scattering of color material particles.

A problem with the image forming apparatus having such a configuration is that the mesh-shaped control electrode 76 has a mesh hole diameter of about 100 to 150 μm, and the color material particles fly as a lump. As shown in (1), rebound occurs on the recording paper 32, and the recording paper 32 becomes soiled, resulting in a high background. This is, of course, a weakness not only in the rebound phenomenon but also in the recording process itself in which the color material particles are caused to fly in an aggregate, and is the greatest factor that deteriorates the graininess. Further, if the recording paper 32 being conveyed has a speed fluctuation, the control by the mesh electrode 76 has little effect on the speed fluctuation.

Also, an image forming method in which an image is formed by applying an adhesive substance to a powder image on an intermediate transfer member made of a flexible member, or by applying an adhesive substance to recording paper or a three-dimensional object. An image forming apparatus that forms a color image by forming a powder image by an apparatus or an electrophotographic method first and transferring it to an adhesive sheet a plurality of times using heat and pressure, or a color material melting temperature. A recording technique that presses a pressure-sensitive adhesive sheet with a low softening temperature onto a photoreceptor to transfer a color material image, or forms an adhesive pattern image on a heat-sensitive adhesive sheet with a thermal head or the like and uses magnetic powder that can be magnetized Recording techniques and the like in which a master (plate) is created and then transferred using a magnetic coloring material have been proposed.

Further, there is also an example in which a polymer whose elastic modulus sharply decreases by application of heat is applied to an image forming apparatus as an image carrier. A belt-shaped image carrier is formed using a polymer having a long-chain alkyl group having 12 to 22 carbon atoms, and heat is directly applied to the belt-shaped image carrier by a thermal head, or an LED is used.
And an image forming process for forming an adhesive / non-adhesive pattern on the polymer by heat generated by light irradiation by an LD laser.

However, each of these methods is effective in solving the problem that a latent image or a visible image pixel position shift occurs due to an optical writing process and a transfer process using an LD laser beam on an electrophotographic photosensitive member. It cannot be an effective means.

Of course, these methods are similar to the development and transfer techniques of a color material in a general electrophotographic system.
There is no idea to match the position where the color material particles adhere to the pixel position without shifting.

From the above, it is an object of the present invention to provide an image forming apparatus in which the color misregistration caused by the distortion of the image carrier can be satisfactorily corrected, and the pixel misregistration of the color material particles with respect to the pixel position can be extremely small. With the goal.

[0046]

In order to achieve the above object,
In the image forming apparatus according to the first aspect of the present invention, a unit pixel region provided with a strong adhesive force generating portion for attaching a color material particle with a strong color material adhesive force by an external stimulus is arranged in a line in a main scanning direction in a unit row. An image forming area configured by arranging a plurality of unit rows in the sub-scanning direction so as to include a detection unit row including a unit pixel area in which at least a part of the reflectance is different from the reflectance of another unit row. Latent image forming means for applying a stimulus to the unit pixel area at a position corresponding to the output image data to attach a color material, and forming a latent image in the image forming area by a color material adhesion force distribution. Detecting the unit rows for detection by measuring reflected light from the image carrier and the image carrier surface at a plurality of locations determined at predetermined intervals along the main scanning direction of the image carrier. Unit row detecting means, and a detecting unit row detecting means. Calculating the amount of curvature of the image carrier based on the detection time difference of the unit row at a plurality of locations detected by the method, and correcting the image data based on the obtained calculation result, thereby providing the stimulation by the latent image forming means. Latent image forming signal control means for correcting the application timing.

That is, in the image forming apparatus according to the first aspect of the present invention, since the unit pixel region forming one pixel is provided with a strong adhesive force generating portion having strong adhesive force at the center, the pixel position of the color material particles is reduced. Displacement is less likely to occur.

Further, according to the first aspect of the present invention, a latent image is formed by a unit row detecting means using an image carrier in which the reflectance of at least one unit row is different from that of another unit row. Before, the reflected light from the surface of the image carrier was measured while rotating the image carrier at a plurality of positions determined at predetermined intervals along the main scanning direction of the image carrier. With a relatively simple mechanism of calculating the amount of curvature of the image carrier from the result, the amount of curvature of the image carrier can be obtained with high accuracy.

Further, in order to detect the distortion state of the image carrier, a detection unit row comprising at least one unit row having a reflectance different from that of another unit row is used. When detecting the amount of curvature, there is no danger of being stained by the color material particles. Needless to say, the amount of color material used is reduced accordingly, so that the cost can be reduced. In addition, since a bending detecting member that needs to be precisely attached to an image carrier such as an encoder disk is not required, manufacturing efficiency and manufacturing cost can be reduced. Incidentally, as in the invention according to claim 2, the reflectance of the unit row for detection may be configured to change the reflectance of only the strong adhesive force generating unit, or the unit excluding the strong adhesive force generating unit. The reflectivity of only the pixel region may be changed, or the reflectivity of the entire unit pixel region may be changed. Of course, if the reflectance of the detection unit row is different from that of the other unit rows, the reflectance may be higher than the other unit rows or lower than the other unit rows.

Also, the invention of claim 3 is the invention of claim 1 or 2
In the image forming apparatus described in (1), the detection unit row detection means includes an illumination optical system that irradiates the surface of the image carrier with one of a laser diode and a high-brightness LED. These laser diodes and high-brightness LEDs
This is preferable because the price and operability are good.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the detecting unit row detecting means detects reflected light using a photodiode. Configuration. This photodiode is preferable because of its good price and good operability.

Further, the strong adhesive force generating portion is made of a wax which is liquefied by heating to increase the liquid cross-linking force or a side-chain crystalline polymer whose surface elastic modulus is increased by heating. 10. The image forming apparatus according to claim 6, wherein the latent image forming means heats the strong adhesive force generating section by applying a latent image forming signal to generate an adhesive force on the surface of the image carrier. As in the present invention, it is possible to adopt a structure in which a member having a strong adhesive force to the color material particles is always taken in and out, so that an adhesive force is generated on the surface of the image carrier.

That is, in the image forming apparatus according to the sixth aspect of the present invention, the base is expanded by the heat generated by irradiating the light-to-heat conversion element with the laser light by the laser generating means, and is formed on the upper surface of the base. An adhesive force is generated on the surface of the image carrier by pushing up a strong adhesive force generating section made of a substance having an adhesive force to the color material particles so as to protrude from the surface of the image carrier.

Further, in the image forming apparatus according to the present invention, the base portion is expanded by the thermal head, is formed on the upper surface of the base portion, and is made of a substance which always has an adhesive force to the color material particles. The strong adhesive force generating section is pushed up so as to protrude from the surface of the image carrier, thereby generating an adhesive force on the surface of the image carrier.

Further, in the image forming apparatus according to the present invention, a signal is applied to the image data at the corresponding position based on the stimulus application timing input by the latent image forming signal generating means to cause distortion in the piezoelectric ceramic. The image carrier is pushed up by pushing up a strong adhesive force generating portion formed on the upper surface of the piezoelectric ceramic and made of a substance that always has an adhesive force to the color material particles so as to protrude from the surface of the image carrier. It causes adhesion to the surface.

According to the ninth aspect of the present invention, the linear actuator is driven by applying a signal to the image data at the corresponding position based on the stimulus application timing input by the latent image forming signal generating means. By moving the upper base up and down (linear movement in the direction perpendicular to the surface of the image carrier), the base is always made of a substance having an adhesive force to the color material particles and formed on the upper surface of the base. The strong adhesion portion is pushed up so as to protrude from the surface of the image carrier, thereby generating an adhesion force on the surface of the image carrier.

[0057]

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, an embodiment in which the present invention is applied to a tandem color image forming apparatus will be described.

(Configuration) FIG. 1 shows a tandem color image forming apparatus 10 according to this embodiment. The tandem color image forming apparatus 10 includes a document reading unit 12 that reads a document and converts the image data into image data, an image data operation processing unit 14 that performs color separation of the obtained image data, and a color (K).
(Black), C (cyan), M (magenta), Y (yellow)) and four image forming stations 20 </ b> Y, 20 </ b> Y, which transfer the color material images in the same area of the intermediate transfer body 30.
0M, 20C, and 20K, and a secondary transfer unit 16 that transfers the multicolor color material image formed on the intermediate transfer body 30 to the recording paper 32
And an intermediate transfer body cleaning unit 18 that removes residual foreign matter from the secondary transfer-completed intermediate transfer body 30.

The four image forming stations 20Y, 20
M, 20C, and 20K are image carriers 22Y, 22M, 22C, and 22K configured such that the reflectance of one unit row in the main scanning direction is different from the reflectance of the other unit rows (detailed configuration is described below). And the image carriers 22Y, 22M, 22
C, color material particle supply and removal means 24Y, 24M, 24C, 24K for supplying a color material to the surface of 22K to form a color material image;
Primary transfer unit 26 that transfers the color material image formed on the surface of image carriers 22Y, 22M, 22C, and 22K to intermediate transfer body 30
Y, 26M, 26C, and 26K and unnecessary foreign matter removing units 28Y, 28M, 28C, and 28K that remove residual foreign matter from the image carriers 22Y, 22M, 22C, and 22K after the transfer of the color material images.
And image carriers 22Y, 22M, and 2 before the latent image is formed.
Curve detectors 21K, 21C, 21M, and 21Y (detailed configuration will be described later) that detect rows with different reflectances on the surfaces of 2C and 22K to detect the curved state of image carriers 22Y, 22M, 22C, and 22K. It is configured.

Next, the image carrier 22 in the present embodiment will be described.
The configurations of Y, 22M, 22C, and 22K will be described with reference to FIGS. The image carriers 22Y, 22M, 2M
Since 2C and 22K have the same configuration, the image carrier 22 will be described with reference numerals.

As shown in FIG. 2, the image carrier 22 has a cylindrical thin aluminum support layer 50, and a thickness of about 5 μm to 500 μm formed on the support layer 50. 42 at the position corresponding to the center of 42
and a porous layer 41 made of a thermoplastic resin such as polyimide having a large number of holes of about 21 μm to 21 μm.

On the surface of the image carrier 22, there are formed a plurality of unit pixel regions 42 having a coloring material attachment portion 45 (see FIG. 3) having a strong attachment force in a hole formed in the center. The unit pixel areas 42 are arranged in a line in the scanning direction to form a unit row (in FIG. 2, seven unit rows 44a to 44g are shown for the sake of explanation). The image forming area 40 having the pixel arrangement of FIG.

In this embodiment, one unit row is configured as a unit row for detecting distortion of the image carrier, which will be described later. The unit row for distortion detection is a mirror image processing after baking white paint on the area other than the color material attachment part 45 of the unit pixel area constituting the unit row to increase the reflectivity, thereby increasing the reflectance with other unit rows. They are configured to have different reflectivities.

Conversely, for example, after baking black paint on the area other than the color material adhering portion 45 of the unit pixel area constituting the unit row, the reflectance is lowered by performing a bare surface treatment to reduce the reflectance. It can also be configured to have a different reflectivity than the rows.

Of course, as shown in FIG. 12, even if the reflectance of only the color material attaching portion 45 is changed to provide a reflectance different from that of the other unit rows, the reflectance of the entire unit pixel area 42 is changed. May be configured to have a reflectance different from that of other unit rows.

As shown in FIG. 3B, each image area has a distance L1 between the centers of adjacent unit pixel areas 42 and an inner diameter L of a hole in which the color material attaching portion 45 is provided.
2. The outer diameter of the color material attachment portion 45 is L3, and the color material particles 3 to be used
When the diameter of No. 4 is d1, L3 <L2 <d1 <L1.

The coloring material attaching section 45 includes a driving section including a photothermal conversion element 47 for generating heat by laser light and a base section 46 expanded by heating on the lower layer side.
In this configuration, laser light is emitted from the inside of the support layer 50 to the photothermal conversion element 47 by the laser generating means 60.

When the light-to-heat conversion element 47 is not irradiated with laser light, the coloring material attachment portion 45 is disposed at a position retracted from the surface of the perforated layer 41 (the state shown on the right side of FIG. 3B), When the conversion element 47 is irradiated with laser light, the temperature of the photothermal conversion element 47 rises and heats the base portion 46, and this heating expands the base portion 46 to push up the color material attachment portion 45, so that the color material The attachment part 45 is a perforated layer 41
Is projected from the surface of. The coloring material particles 34 adhere to the protruding coloring material attaching portion 45 to form one pixel.

Since it is desirable that the laser light generated from the laser generating means 60 reaches the photothermal conversion element 47 without loss, the support layer 50 existing in the laser light path is not required.
It is preferable to use a material having a sufficiently high laser light transmittance. Preferably, the support layer 50 is made of a material having the highest possible transparency. Since the photothermal conversion element 47 desirably has a sufficiently high absorption of laser light, it is preferable to apply a dark black dye to the portion where the laser light is incident.

Here, the unit pixel region 4 having such a configuration is used.
The generation state of the adhesive force to the second color material particles 34 will be described with reference to FIGS. FIG. 4A shows irradiation energy E given to photothermal conversion element 47 of the present embodiment.
And the base portion 4 which expands due to heat generated by the photothermal conversion element 47.
6 shows the relationship with the adhesive force Fa when the coloring material attaching portion 45 pushed up to the surface exerts an adhesive force in the image forming amount area, and FIG. 4B shows the photothermal conversion element due to the irradiation position shift. 47 shows a state of a change in irradiation energy E received by 47.

The state (c) in FIG. 4 (B) is a state where there is no displacement of the irradiation position, and the energy E3 in the hatched portion acts on the light-to-heat conversion element 47 to push up the coloring material adhering part 45 (A). As shown in (c), the adhesive force Fa1 required for holding the color material particles is sufficiently obtained. Even if this causes an irradiation position shift as shown in (b) or (b) of (B), if the irradiation energy has reached a certain threshold or more necessary to push up the coloring material adhering portion 45, the color is not changed. Since the material adhering portion 45 is pushed up, a sufficient adhesion Fa1 of the color material particles is obtained as shown in (b) and (a) of (A). That is, when the irradiation energy exceeds a certain threshold, the adhesion Fa of the color material particles in the unit pixel area 42 sharply increases.

As shown in FIG. 5, in the unit pixel area 42 of the present embodiment having such an adhesive force characteristic, the diameter of the unit pixel area 42 is 2L, and the diameter of the color material attaching section 45 is 2Δ.
When X (where ΔX <L), the maximum pixel displacement of the color material particles 34 to be attached is 2ΔX, and the color material attachment portion 45 is configured to be smaller at a fixed ratio with respect to the unit pixel area 42. Therefore, it can be seen that the pixel position shift of the color material particles 34 is sufficiently small. Therefore, the color material particles 3
As shown in FIG. 6, No. 4 adheres to a position that hardly deviates from the image formation scheduled area.

Further, the unit pixel area 42 having such a configuration
As shown in FIG. 7, even when the image signal is input at a position shifted from the pixel position, the portions where the adhesive force can be generated are regularly and discretely arranged. No color shift occurs at the portion where the color shift occurs, and as a result, the color material particles 34 adhere to the individual unit pixel areas 42 without causing a pixel position shift.

As a comparative example, an image forming state in the case where the entire pixel region has an adhesive force to the color material particles 34 will be described with reference to FIGS. As shown in FIG. 8, when the diameter of the unit pixel area 42 is 2L,
The maximum pixel displacement of the attached color material particles 34 is 2L, and therefore, as shown in FIG. 9, it can be seen that the color material particles 34 protrude from the target image forming area with a high probability and adhere.

Further, even when the image signal is input at a position shifted from the pixel position, the area where the adhesive force can be generated is spread over the entire unit pixel area. Therefore, as shown in FIG. It can be seen that the color material particles 34 adhere to a position that is significantly shifted from the pixel position to be set, and further positional shift occurs.

FIG. 11 is a graph showing the frequency of misregistration measured for 60 color material particles when the image carrier 22 of the present embodiment is used. In addition, the graph shown by the dotted line is a graph showing the frequency of misregistration measured for 60 color material particles when a conventionally used image carrier is used. As is clear from the graph of FIG. 11, when the image carrier 22 of the present embodiment is used, many color material particles 29 are present in the range of 0 to 9 μm, and a considerably high image quality can be expected. On the other hand, when the conventionally used image carrier is used, the distribution of the pixel position shift is very wide, and it can be seen that it is far from the desired state. Therefore, by using the image carrier 22 of the present embodiment, the amount of misalignment of the color material particles becomes extremely small, and the color material particles can be aligned with the corresponding pixel positions with high precision.

In the above embodiment, the image carrier is cylindrical, but may be a two-dimensional flat plate. The support layer 50
Is made of a thermoplastic resin such as polyimide, but any material that allows a laser beam to pass through may be used.

The porous layer 35 having low adhesion properties is made of stainless steel, but is formed of a material having low adhesion to coloring material particles and having excellent wear resistance and heat resistance. It is possible to use a general metal material or a polyimide or the like which has a little concern about abrasion resistance but is excellent in heat resistance and workability.

Next, the bending detector 2 in the present embodiment
1 will be described with reference to the drawings. As shown in FIG. 16, the curvature detection unit 21 includes a detection reference light generation unit 81 a that irradiates light to the image carrier 22, and a light emitted from the reference light generation unit 81 a on the surface of the image carrier 22. Three detection unit row detection units 80a, 80b, and 80c each including a reflection light detection unit 81b that detects reflected light; and an image carrier based on detection results from the detection unit row detection units 80a, 80b, and 80c. A reflected light data analysis unit 82 that calculates the amount of curvature of the body surface and outputs the data as the amount of curvature, and a latent image forming signal control that corrects an image forming signal based on the amount of curvature data output from the reflected light data analysis unit 82 And a section 84.

The detection reference light generator 81a can be constituted by a general light source, but by using a laser diode or a high-brightness LED, low cost and good operability can be realized. In addition, the reflected light detection unit 81b can be configured by a photodiode, a photoelectric tube, or the like. However, if it is preferably configured by using a photodiode, low cost and good operability can be realized.

The three detection unit row detection units 80a, 80
b and 80c are, as shown in FIG. 16B, both end positions (R position (right end position), L position (left end position)) and center position (C position (center position)) of the image carrier. ) Are arranged along the longitudinal direction (main scanning direction) of the image carrier, and the reflected light at each position is detected to detect the passage timing of the unit row. In addition, 3
If the two detection unit row detection units 80a, 80b, 80c are arranged as close as possible to the position where the latent image is formed on the surface of the image carrier by the laser generation means 60, which is a latent image formation signal generation unit, This is preferable because the amount of deformation or rotation of the image carrier 22 at the latent image forming point can be detected without attenuation.

The reflected light data analyzer 82 detects the curved state of the image carrier based on the passage timings at three locations detected by the three detection unit row detectors 80a, 80b, 80c, respectively.

For example, when the image carrier is distorted as shown in FIG. 17, the detection unit row is curved according to the amount of curvature of the image carrier 22 as shown in FIG. Therefore, three detection unit row detection units 80a, 80b, 80c
The detection time of the reflected light of the unit row at three positions (R position, C position, and L position) is t1 at the L position and t at the C position.
3. At the R position, t24 (provided that t1 <t2 <t3). Therefore, when the signal from the unit row detection unit 80a at the L position is an L signal, the signal from the unit row detection unit 80c at the R position is an R signal, and the signal from the unit row detection unit 80b at the C position is a C signal, FIG. B).

In the signal waveform shown in FIG. 18B, the position where the traveling waveform behaves differently from the others is the position of the unit row. Therefore, the reflected light data analysis unit 82 determines the timing at which this change position is detected. The home position is detected, and the obtained three home position detection timings t1, t2,
Based on t3, the distance delta _IC corresponding to the shift amount of the detection time of the C position with respect to the detection time of the L position, a distance delta _IR corresponding to the shift amount of the detection time of the R position to the detection time of the L position
Is detected and output to the latent image forming signal control unit 84.

[0085] latent image forming signal controller 84, an input distance delta _IC, advancing the time t2, t3 only the latent image formation signal generating timing corresponding to the delta _IR, or delayed as adjusted.

That is, when the bending amount data is input from the reflected light data analysis unit 82, the latent image formation signal control unit 84 determines the latent image formation timing from the image data as follows, for example.

First, three detection unit row detection units 80a,
The measurement points by 80b and 80c are R position, C position,
Since there are three points at the L position, as shown in FIG. 19, xy coordinates based on the L position are assumed, and when each position is represented by coordinates, the L position (x ₀ , y ₀ ) and the C position (xc, xc, y
c), R position (x _i, a y _i).

[0088] Here, the distance delta _Ic corresponding to the amount of deviation of the aforementioned time, since the coordinates of the R position and the position C is determined from delta _IR, the deformation amount of the image ^{carrier, y = ax 2 + bx +} c ...
The coefficients a, b, and c can be calculated by approximating by the quadratic function of (1) and substituting each into the above equation (1). The latent image forming signal control unit 84 corrects the image writing timing, that is, the stimulus applying timing while interpolating the image data using the calculated a, b, and c.

Table 1 shows an example of the correction of the stimulus application timing. This example is a table for correcting the image data for one unit row. If this process is repeated n times, the stimulus application timing for n unit rows can be corrected.

[0090]

[Table 1]

(Operation) Next, the operation of the present embodiment will be described. First, the color image data read from the original in the original reading unit 12 is output to the image data arithmetic processing unit 14.
The image data is subjected to predetermined image calculation processing in the image data calculation processing section 14, is subjected to color separation, and is output to each printing station 20Y, 20M, 20C, 20K for each color.

Each printing station 20Y, 20M, 20
For C and 20K, the curvature detectors 21K, 21C, 21M,
The image carriers 22Y, 22M, 22C, 2
The 2K bending amount is detected, the input image data is corrected based on the obtained bending amount, and the corrected image data is output to a latent image forming unit (not shown). The latent image forming section forms a latent image based on the corrected image data on the image carriers 22Y, 22M, 22C, and 22K, and moves the latent image to the developing area with the rotation of the image carriers 22Y, 22M, 22C, and 22K. The color material is supplied to the image portion by the color material particle supply / removal means 24Y, 24M, 24C, and 24K to visualize the image. Thereby, the image carrier 22
The color material images formed on the surfaces of Y, 22M, 22C, and 22K move to the primary transfer area as the image carriers 22Y, 22M, 22C, and 22K rotate.

In the primary transfer area, primary transfer sections 26Y, 26M, 26C, 26K constituted by roller members are arranged. These primary transfer sections 26Y, 26M, 26C,
An intermediate transfer member 30 is sandwiched between 26K and the image carriers 22Y, 22M, 22C, and 22K.

The primary transfer sections 26Y, 26M, 26C, 26
K represents the image carriers 22Y, 22Y from the back side of the intermediate transfer body 30.
The color material images on the image carriers 22Y, 22M, 22C, and 22K are transferred to the intermediate transfer body 30 by applying a pressing force toward 2M, 22C, and 22K.

Thereafter, the image carrier 22Y after the transfer of the color material image,
The surface portions of the image carriers 22M, 22C, and 22K are
With the rotation of Y, 22M, 22C, and 22K, it moves to the cleaning area. Unnecessary foreign matter removing units 28Y, 28M, 28C, 28K are arranged in the cleaning area,
The unnecessary foreign matter removing units 28Y, 28M, 28C, and 28K remove foreign matters such as color material particles remaining on the surface portions of the image carriers 22Y, 22M, 22C, and 22K and dust attached to the surfaces.

Image carriers 22Y and 22 from which foreign matter has been removed
For M, 22C and 22K, a latent image is formed on the surface again, and the above-described steps are repeated.

On the other hand, the image carriers 22Y, 22M, 22C,
The intermediate transfer body 30 onto which the color material image on 22K is transferred is adjusted by a transporting means (not shown) so that the color material images for each color of one image system read from the document are transferred to the same position. , Four primary transfer units 26Y, 26M, 26C,
The color material images of four colors are transferred in a superimposed manner on the intermediate transfer body 30 that has passed all of 26K.

The four primary transfer sections 26Y, 26M, 26
The intermediate transfer body 30 that has passed all of C and 26K is transported to the secondary transfer unit 16 by a transport unit (not shown), and is thermally pressed to the recording paper 32 supplied from the paper feed tray 15.
As a result, the color material images for the four colors formed on the intermediate transfer member 30 are transferred onto the recording paper 32, and the color material is fixed on the recording paper 32 by heat to form an image. The recording paper 32 on which the image has been formed is transported to the paper discharge tray 17 by a transport unit (not shown).

After the completion of the secondary transfer transfer, the intermediate transfer body 30 is conveyed to the intermediate transfer body cleaning unit 18 and, after the surface residue and the like are removed, the printing stations 20Y, 20M,
20C and 20K, and the above-described steps are repeated.

The basic steps for forming an image using the image carrier having the above-described structure will be described with reference to FIG.
This will be described below. Here, a single-color image forming operation will be described for simplification of the description.

First, all the color material attachment portions 45 formed on the image carrier 22 are retracted from the surface of the image carrier 22 (FIG. 15A; initialization of the image carrier). Next, based on the corrected image data, the color material attachment portion 45 in the pixel area at the corresponding position is made to protrude from the surface of the image carrier 22 to form a latent image based on the adhesion distribution (FIG. 15; latent image). Formation (B)).

Thereafter, color material particles are supplied to the surface of the image carrier (FIG. 15C; supply of color material particles). Excess color material particles 34 are removed by a blade (or brush) 72,
One color material particle 34 is attached to one color material attachment portion 45 (FIG. 15D; unnecessary particle removal). Thereafter, a pressing force is applied to the intermediate transfer body 30 while being in contact with the intermediate transfer body 30 (FIG. 15E), and the color material particles 34 are transferred to the intermediate transfer body 30 (FIG. 15F; primary transfer).

The intermediate transfer body 30 onto which the color material particles 34 have been transferred
Face the recording paper 32 (FIG. 15 (G)), and heat it while applying a pressing force to fix the color material particles 34 (FIG. 15 (G)).
(H): Secondary transfer), and an image is formed on the recording paper 32 by peeling off the intermediate transfer body 30 (FIG. 15 (I)).
In the tandem color image forming apparatus, (A)
To (F) are performed in parallel for a predetermined number of colors,
A full-color image of color material particles 34 of a plurality of colors is formed on the intermediate transfer body 16 in the step (G).

The image formed based on the stimulus application timing obtained as described above is distorted as image data when the image forming area is flattened as shown in FIG. There is no distortion on the image carrier 22 in a curved state, so that a target image is formed on the intermediate transfer member 30 without distortion.

In the tandem color image forming apparatus provided with the image carrier 22 and the curvature detecting unit 21 having the above-described configuration, the amount of the unnecessary color material particles to be collected when the resist mark is formed by the color material particles on the surface of the image carrier. And compared.
The result is shown in FIG. As can be seen from FIG. 21A, in the image forming apparatus of the present embodiment, the collection amount of the unnecessary color material particles is reduced to 52% of the comparative example. This is to form a resist mark with color material particles on the surface of the image carrier to detect the amount of deformation of the image carrier,
It is considered that since it is not necessary to remove the resist mark after detecting the amount of deformation, it is not necessary to use extra color material particles.

The encoder assembly cost was compared with the case where a code wheel was used. The result is shown in FIG. As can be seen from FIG. 21B, in the image forming apparatus according to the present embodiment, the encoder assembly cost has been reduced to 77% of the comparative example. This is because, in the image forming apparatus of the present embodiment, the code wheel of the encoder assembly is not required, so that the cost can be reduced accordingly.

However, this data indicates that, on the surface of the image carrier after passing through the primary transfer area, unnecessary color material particles uniformly remain at an area ratio of 10% in the image area, and the mark outside the image formation area Is a value measured under the condition that the area ratio is uniformly maintained at 75%. If the transfer performance is higher and the residual color material particles in the image forming area are within about 5% of the area ratio, the recovery amount of unnecessary color material particles can be reduced to 36% of the conventional method. The estimation result of is obtained.

It should be noted that the surface of the image carrier described in the present embodiment is supplemented with the reduction in the amount of unnecessary color material particles collected.
For example, as shown in FIG. 3A, since there is a minute uneven shape, the unnecessary residual color material particles can be removed by any of a cleaning blade method, a cleaning brush method, an electrostatic suction method, and an adhesive roll cleaning method. It becomes difficult even if the method is used. Therefore, it is necessary to use the image carrier 22 with as little contamination as possible, and it is advantageous from the viewpoint of cleaning that unnecessary color material particles can be suppressed to a small amount.

In the above description, the case where the present invention is applied to a tandem color image forming apparatus is described. However, the present invention is not limited to only a tandem color image forming apparatus, but is applied to a single color image forming apparatus and a two-color image forming apparatus. It may be introduced into a forming apparatus, a multi-pass full-color image forming apparatus, and the like, and similar effects can be expected.

In this embodiment, the light-to-heat conversion element 47 is used as a driving unit for driving the color material attaching section 45. In the present invention, the color material attaching section 45 is moved up and down in the hole to thereby move the color material attaching section 45 up and down. The drive unit that controls the generation of the adhesive force at the position,
The present invention can be applied to any stimulus of a certain level or higher as long as the change in physical properties is digitally generated.

For example, FIG. 13A shows that the image carrier 22
A configuration is shown in which the base portion 46 is heated and expanded from the inside of the support layer 50 by the thermal head 62 that moves inside in the main scanning direction, and the coloring material attachment portion 45 formed on the upper portion is projected.

In this case, it is desirable to prevent the heat generated from the thermal head 62 from reaching the base portion 46 without any loss and to prevent the heat from propagating to the adjacent latent image forming member. It is preferable that the thickness of the support layer 50 existing between the support layer 46 and the support layer 46 be as small as possible.

Further, since the thermal head 62 slides under the support layer 50 at the same speed as the image forming speed, it is necessary to take measures against abrasion and temperature rise as the image forming speed increases. It is preferable to take measures against abrasion, such as using a high-hardness material for the contact portion or applying or impregnating a lubricant. With respect to the temperature rise, it is preferable to take measures such as applying or impregnating a lubricant, and installing a radiation fin or a radiation fan.

FIG. 13B shows the latent image forming signal generator 6.
4 and a piezoelectric ceramic 65 having a property of being distorted when an electric field such as zirconate titanate (PZT) is applied,
A configuration is shown in which a coloring material attachment portion 45 formed at an upper portion is projected.

In this case, it is desirable to use a piezoelectric ceramic which can provide a large amount of displacement. For example, a laminated piezoelectric element may be used.

FIG. 13C shows the latent image forming signal generator 6.
7, the linear actuator 68 that rises by application of an electric signal and the base 49 that rises with the elevation of the linear actuator 68 project the color material attachment portion 45 formed on the upper portion. In this case, an electrostatic microactuator or the like may be used as the linear actuator 68. Further, as the base portion 49 which is moved up and down by the linear actuator 68, it is preferable to select a material having excellent wear resistance and heat resistance as in the case of the porous layer 41. Polyimide or the like having excellent properties and processability can be used.

In the configuration shown in FIGS. 13B and 13C, a command signal from the latent image forming signal generator 64 is applied to the piezoelectric ceramics 65 or the linear actuator 68 formed in each unit image area. Electrode parts 66, 69
In this method, the lower part of the support layer 50 is slid at the same speed as the image forming speed. Therefore, when the image forming speed increases, a measure against abrasion and a measure against a rise in temperature are required. It is preferable to take measures against abrasion, such as using a high-hardness material for the contact portion or applying or impregnating a lubricant. As for the temperature rise, it is preferable to take measures such as applying or impregnating a lubricant, and installing a radiation fin or a radiation fan.

In the structure described above, the support layer 50 may be made of a metal such as aluminum or stainless steel having good thermal conductivity, or may be made of ceramics, in addition to being made of a thermoplastic resin. The base portion 46 may be made of any material having a higher coefficient of thermal expansion than the porous layer 35, and for example, polyethylene or the like can be used. Further, as the coloring material attaching portion 45, an inexpensive adhesive material having good durability such as silicone rubber is preferable.

FIG. 1 shows another example of the structure of the color material attaching section 45. In FIG.
4 (A) to (C). All of these components are filled with a viscoelastic material such as a wax or a side-chain crystalline polymer which undergoes a reversible solid-liquid phase change by heating or a crystalline-amorphous phase change as a coloring material adhering material 70 in the pores. I did it.

FIG. 14A shows a photothermal conversion element 47 which generates heat by laser light below the colorant-adhering substance 70, and is applied to the photothermal conversion element 47 by the laser generation means 60 from the inside of the support layer 50. This is a configuration in which laser light is irradiated to the laser beam.

When the photothermal conversion element 47 is not irradiated with a laser beam, the colorant-adhering substance 70 has a low adhesion to the colorant. When the light-to-heat conversion element 47 is irradiated with a laser beam as an external stimulus, the temperature of the light-to-heat conversion element 47 rises, and the adhesion of the coloring material-adhering substance 70 becomes high. To form one pixel.

In this case as well, the laser light generated by the laser generating means 60 is applied to the photothermal conversion element 47 in the same manner as described above.
It is desirable that the support layer 50 existing in the laser beam path be made of a material having sufficiently high laser beam transmittance. Preferably, the support layer 50 is made of a material having the highest possible transparency. Since the photothermal conversion element 47 desirably has a sufficiently high absorption of laser light, it is preferable to apply a dark black dye to the portion where the laser light is incident.

FIG. 14B shows the support layer 5 formed by the thermal head 62 moving in the main scanning direction inside the image carrier 22.
A configuration is shown in which the coloring material adhering substance 70 is heated from the inside of 0 to increase the adhering force, and the coloring material particles are adhered to the upper surface.

Also in this case, similarly to the above, the heat generated from the thermal head 62 reaches the coloring material adhering substance 70 without loss.
Further, since it is desirable to prevent heat from being transmitted to the adjacent latent image forming member, the thermal head 62 and the coloring material adhering substance 7
It is desirable to make the thickness of the support layer 50 existing between 0 and 0 as small as possible.

Further, since the thermal head 62 slides under the support layer 50 at the same speed as the image forming speed, it is necessary to take measures against abrasion and temperature rise as the image forming speed increases. It is preferable to take measures against abrasion, such as using a high-hardness material for the contact portion or applying or impregnating a lubricant. With respect to the temperature rise, it is preferable to take measures such as applying or impregnating a lubricant, and installing a radiation fin or a radiation fan.

FIG. 14C shows the color material adhering substance 70.
Thermal head 62 that generates heat by applying an electric signal to the lower layer side
And a latent image forming signal generator 6 from the inside of the support layer 50.
7, an electric signal is applied to the thermal head 62.

The electrode section 69 for applying the command signal from the latent image forming signal generating section 67 to the thermal head 62 formed in each unit image area slides under the support layer 50 at the same speed as the image forming speed. Therefore, when the image forming speed increases, measures against wear and temperature rise are required. It is preferable to take measures against abrasion, such as using a high-hardness material for the contact portion or applying or impregnating a lubricant. As for the temperature rise, it is preferable to take measures such as applying or impregnating a lubricant, and installing a radiation fin or a radiation fan.

Although the above description has been given of a configuration in which the color material attaching portion 45 is entirely formed in the perforated layer 41, a hole is not necessarily required, and the color material attaching portion 45 is formed in the center of the unit pixel region 42. It suffices if the area is configured to occupy the unit pixel area 42 at a certain fixed ratio in the area, and is configured to be regularly and regularly arranged at a predetermined pitch in accordance with a required resolution. For example, if the size of one pixel is 120
One of the basic mechanisms of the present invention can be configured if the size of a portion that generates an adhesive force is smaller than 0 dpi, that is, a unit pixel region 37 of 21.2 μm × 21.2 μm.

[0129]

As described above, according to the first aspect of the present invention, the color misregistration caused by the distortion of the image carrier is corrected well and the pixel misregistration of the color material particles with respect to the pixel position is extremely small. There is an effect that it can be done.

Further, according to the invention of claim 2, there is an effect that a mark for detecting the amount of curvature of the image carrier can be formed with a relatively simple configuration.

Further, according to the third and fourth aspects of the present invention, there is an effect that the price and the operability are good.

Further, according to the inventions of claims 5 to 9, there is an effect that the pixel position deviation of the color material particles with respect to the pixel position can be extremely reduced by a relatively simple mechanism.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a tandem color image forming apparatus 10 according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an image carrier 22 used in the tandem color image forming apparatus shown in FIG.

FIG. 3 is an explanatory view showing a schematic configuration of an image carrier 22 shown in FIG. 2, (A) is a partial perspective view of the image carrier 22,
FIG. 2B is a partial sectional view of the image carrier 22.

FIG. 4 is an explanatory diagram showing a case in which light irradiation of an input signal causes a position shift with respect to a unit pixel region.

5 is an explanatory diagram showing a shift amount of a coloring material particle 34 attached to a coloring material attaching portion 45 of the image carrier 22 shown in FIG. 2;

FIG. 6 is a top view illustrating a state in which color material particles adhere to an image forming area in the image carrier 22 illustrated in FIG. 2;

FIG. 7 shows an image signal when an image signal is input to the image carrier 22 shown in FIG. 2 while being shifted from a pixel area, a pixel position formed in an image forming area, and an attached state of color material particles. FIG.

FIG. 8 shows color material particles 3 adhering to a unit pixel region when the entire surface of the unit pixel region has an adhesive force to the color material particles 34.
FIG. 4 is an explanatory diagram showing a shift amount of No. 4;

FIG. 9 is a top view illustrating a state of attachment of color material particles to an image formation scheduled region when the entire surface of the unit pixel region has an adhesive force to the color material particles.

FIG. 10 shows an image signal when an image signal is input shifted from the pixel region when the entire surface of the unit pixel region has an adhesive force to the color material particles 34, and a pixel position formed in the image forming region. FIG. 4 is an explanatory view showing the state of attachment of color material particles.

FIG. 11 shows the frequency of misregistration measured with respect to 60 color material particles when the image carrier 22 of the present embodiment is used and the case where the image carrier of a conventional configuration is used. 6 is a graph showing the frequency of misregistration measured for 60 color material particles.

FIG. 12 is an explanatory diagram showing another configuration of a detection unit row formed on the image carrier 22 shown in FIG. 2;

13A and 13B illustrate another example of the configuration of a drive unit that controls the generation of an adhesive force at a position by moving a color material attachment unit 45 up and down in a hole. FIG. FIG. 7B is a schematic explanatory view showing a configuration using a base unit 46 that performs the operation, and FIG. 7B is a schematic explanatory view showing a configuration using a latent image forming signal generating unit 64 and a piezoelectric ceramic 65 as a driving unit. () Is a schematic explanatory view showing a configuration using a latent image forming signal generating section 67, a linear actuator 68, and a base section 49.

14A and 14B are configuration examples in the case where a coloring material-adhering substance 70 whose adhesive force to coloring material particles increases when heat is applied is used as the coloring material-adhering portion 45, and FIG. 47B is a schematic explanatory view showing a configuration using a thermal head 62, FIG. 47B is a schematic explanatory view showing a configuration using a thermal head 62, and FIG. FIG. 3 is a schematic explanatory diagram showing a configuration using a.

FIG. 15 is an explanatory diagram showing a basic process of forming an image using the image carrier according to the embodiment.

FIG. 16A is a schematic diagram illustrating a configuration of a bending detection unit according to the present embodiment, and FIG. 16B is a description illustrating a positional relationship between three detection unit row detection units 80a, 80b, and 80c. FIG.

FIG. 17 is an explanatory diagram illustrating a curved state of the image carrier according to the present embodiment;

FIG. 18A is an explanatory diagram showing a curved state of a unit row,
(B) shows three detection unit row detection units 80a, 80b, and 8;
It is explanatory drawing which shows the signal waveform by 0c.

FIG. 19 is a diagram in which the amount of deformation of the image carrier is approximated by a quadratic function based on the L position.

FIG. 20 is an explanatory diagram illustrating an image forming state by the image forming apparatus according to the present embodiment.

FIG. 21A is a histogram showing the amount of collected unnecessary color material particles in the image forming apparatus of the present embodiment,
6B is a histogram illustrating an encoder assembly cost in the image forming apparatus according to the present embodiment.

FIG. 22 is an explanatory diagram illustrating a curved state of a photosensitive drum in a conventional image forming apparatus.

FIG. 23 is an explanatory diagram when an image is formed using a curved photosensitive drum.

FIG. 24 is a configuration example of an arrangement that can be considered to suppress the amount of bending in a conventional image forming apparatus.

FIG. 25 is an explanatory diagram showing a spatial electric field formed between a regular rectangular latent image on a photoconductor and a developing electrode.

26 is a graph showing a result of calculating a contrast potential distribution along a Y direction in FIG. 25 by calculation.

FIG. 27 is a schematic configuration diagram of a conventional image forming apparatus for visualizing a color material by bias development.

FIG. 28 is a partial cross-sectional view of the imaging drum 96 used in the image forming apparatus shown in FIG. 27;

29A is a schematic configuration diagram of a conventional color material jet image forming apparatus, and FIG. 29B is an explanatory diagram showing a state in which color material particles are attached to a recording paper 32 by flying.

[Explanation of symbols]

Reference Signs List 10 Tandem color image forming apparatus 12 Original reading unit 14 Image data processing unit 16 Secondary transfer unit 18 Intermediate transfer body cleaning unit 20Y, 20M, 20C, 20K Image forming station 21K, 21C, 21M, 21Y Curve detecting unit 22Y, 22M , 22C, 22K Image carrier 24Y, 24M, 24C, 24K Color material particle supply and removal unit 26Y, 26M, 26C, 26K Primary transfer unit 28Y, 28M, 28C, 28K Unnecessary foreign matter removal unit 30 Intermediate transfer body 32 Recording paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Usui 430 Sakai Nakaicho, Ashigarashimo-gun, Kanagawa Prefecture Inside Green X-Tech Fuji Xerox Co., Ltd. (72) Inventor Yoshiro Yamaguchi 430 Nakai-cho, Nakai-machi, Ashigara-gun, Kanagawa Prefecture Inside Fuji Xerox Fuji Xerox Co., Ltd. ) 2H027 DA22 DA38 DE02 EC06 EC07 ED06 EE02 HB07 2H030 AA01 BB02 BB16 2H072 AA03 AA16 AA36 AB07

Claims (9)

[Claims] 1. A unit pixel region having a strong adhesive force generating portion for attaching a color material particle with a strong color material adhesive force by an external stimulus at a central portion is arranged in a line in a main scanning direction to form a unit row, and at least a part of the unit pixel region An image forming area in which a plurality of unit rows are arranged in the sub-scanning direction so as to include a detection unit row including a unit pixel area having a reflectance different from that of another unit row; and output image data. A latent image forming means for applying a stimulus to the unit pixel region at a position corresponding to and attaching a color material, and forming a latent image based on a color material adhesion distribution in the image forming region; A detection unit row detecting means for detecting the detection unit row by measuring reflected light of the image carrier surface at a plurality of locations determined at predetermined intervals along the main scanning direction of the image carrier; Detected by the detection unit row detection means. Correcting the stimulus application timing by the latent image forming means by calculating the amount of curvature of the image carrier based on the detection time difference of the unit row at a plurality of locations and correcting the image data based on the obtained calculation result And a latent image forming signal control unit. 2. The detection unit row is configured such that at least one of the strong adhesive force generating unit and a unit pixel region excluding the strong adhesive force generating unit has a different reflectance from other unit rows. The image forming apparatus according to claim 1. 3. An illumination optical system for irradiating the surface of the image carrier with one of a laser diode and a high-brightness LED.
Or the image forming apparatus according to 2. 4. The image forming apparatus according to claim 1, wherein the detection unit row detection unit detects the reflected light using a photodiode. 5. The strong adhesion generating portion is made of one of a wax, which is liquefied by heating to increase liquid cross-linking force, and a side-chain crystalline polymer, which has a surface elastic modulus increased by heating, The image forming apparatus according to claim 1, wherein the latent image forming unit heats the strong adhesive force generating unit by applying a latent image forming signal. 6. The laser printer according to claim 1, wherein the latent image forming unit irradiates a laser beam to a unit pixel position corresponding to the image data, and the photothermal conversion element generates heat by irradiating the laser beam from the laser generating unit. And a base portion which expands by heating, wherein the strong adhesive force generating portion is always made of a substance having an adhesive force to the color material particles, and is pushed up by the latent image forming means so as to protrude from the surface of the image carrier. The image forming apparatus according to claim 1, wherein: 7. The latent image forming means comprises a thermal head and a base portion which expands by heating, wherein the strong adhesive force generating portion is made of a substance having an adhesive force to color material particles at all times. The image forming apparatus according to any one of claims 1 to 4, wherein the latent image forming unit pushes up the image carrier so as to protrude from the surface of the image carrier. 8. The latent image forming means includes: a latent image forming signal generating means for applying a signal to image data at a corresponding position based on the input stimulus applying timing; and a distortion in a thickness direction by applying the signal. Wherein said strong adhesive force generating section is made of a substance having an adhesive force to color material particles, and is pushed up by said latent image forming means so as to protrude from the surface of the image carrier. The image forming apparatus according to claim 1. 9. The latent image forming means for applying a signal to image data at a corresponding position based on the input stimulus application timing, and the latent image forming means moves in the thickness direction by applying the signal. A linear actuator and a base portion provided on the linear actuator and having a strong adhesive force generating portion in an upper layer, wherein the strong adhesive force generating portion is made of a material having an adhesive force to color material particles at all times. 5. The image forming apparatus according to claim 1, wherein the latent image forming unit is pushed up so as to protrude from the surface of the image carrier. 6.