JP2001265194A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an image, by which toner for on the non-image area is reduced, and moreover wearing of a photoreceptor is suppressed, when forming the image on a printing plate by adopting a conventional printer. SOLUTION: In an electrophotographic image forming device of a processing cartridge system, the image formation is performed by forming at least one selected from an adopted electrophotographic photoreceptor, toner and a cleaning means into a different individual cartridge and by exchanging the cartridge according to the paper sheet that the image is transferred thereon and/or the image forming purpose.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an image on a lithographic printing plate using a detachable process cartridge in a copying machine, a printer or the like using an electrophotographic system.

[0002]

2. Description of the Related Art An image forming apparatus such as a printer forms a latent image by selectively exposing a uniformly charged photosensitive drum to a latent image, and visualizes the latent image with toner. The image is transferred to a recording medium to record the image. In such an apparatus, the toner must be replenished each time the toner runs out. However, this toner replenishment operation is not only troublesome, but also involves contamination. In addition, maintenance of each member can only be performed by a specialized service person, which often causes inconvenience to the user. Therefore, the photosensitive drum, the charger, the developing device, the cleaning unit, and the like are integrated into a cartridge to form a cartridge. Components that can replace parts such as a body drum and facilitate maintenance have been put to practical use.

On the other hand, a CTP (computer-to-plate) for directly making data created on a computer into a printing plate can also be output as a printing plate using a general-purpose printer without using an expensive dedicated output system or plate material. Some CTPs that are light and inexpensive by outputting various plate materials are also in practical use.

However, a general-purpose printer is made for plain paper, and a printing plate having a surface shape and characteristics different from that of plain paper is liable to cause toner coverage on a non-image portion.
It has been pointed out that ink is applied during printing to cause a so-called background stain, resulting in a printed matter having a low contrast between an image portion and a non-image portion.

[0005] In particular, a printing plate having a hydrophilic surface is generally roughened for the purpose of enhancing water retention. When such a printing plate comes into contact with the surface of the photoreceptor, the abrasion of the photoreceptor becomes faster than that of plain paper having a relatively smooth surface. The surface of the photoreceptor wears as the paper passes, but if the photoreceptor is worn beyond a certain thickness, it becomes difficult to maintain an appropriate output, and it is necessary to replace the cartridge. For this reason, the replacement frequency increases, and the running cost of the user increases.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to reduce the amount of toner covered in a non-image area, especially when an image is output to a printing plate using a general-purpose printer. An object of the present invention is to provide an image forming method in which abrasion of a body is suppressed.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found the following invention.

A first invention is a process cartridge type electrophotographic image in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachable from an image forming apparatus main body. In the forming apparatus, at least one selected from an electrophotographic photosensitive member, a toner, and a cleaning unit to be used is formed as a different individual cartridge, and the cartridge is replaced according to a sheet onto which an image is transferred and / or an image forming purpose, thereby forming an image. It is characterized by doing.

According to a second aspect of the present invention, the image forming condition information attached to the cartridge is read by the main body of the electrophotographic image forming apparatus, and at least one selected from a conveying speed and a fixing temperature is changed in accordance with the condition to execute processing. It is characterized by performing.

According to a third aspect of the present invention, the sheet for transferring the image is a printing original plate having at least a hydrophilic surface,
It is characterized in that the purpose of image formation is to make the printing original plate.

According to a fourth aspect of the present invention, in the electrophotographic photosensitive member used in the cartridge, the surface of the photosensitive member has a pencil hardness of 6H.
It is characterized by the above.

A fifth aspect of the present invention is characterized in that the cleaning means used in the cartridge is provided with a plurality of individual cleaning means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view showing an example of a cartridge relating to the image forming method of the present invention. A photoreceptor 1, a developing roller 2, a charging charger 3, and cleaning blades 51 and 52 are arranged in the cartridge A. A recognition tag 6 indicating image forming conditions (in this example, plate making use) for each application is provided on the outer surface of the housing. is set up.

The cartridge A is freely detachable as an image forming engine of a laser printer, and can be replaced according to the purpose of forming an image, such as a plain paper output or a printing plate output. When the cartridge A is mounted on the laser printer, the recognition tag 6 comes into contact with recognition means (a plurality of conduction confirmation members) on the laser printer side, and the type of the cartridge is confirmed by the conduction pattern of the plurality of conduction members. The recognition tag 6 is a conductor (metal surface) according to the type of the cartridge.
And a pattern of the non-conductive portion (the surface coated with the insulating paint) is formed.

The photoreceptor 1 rotates in the direction of the arrow in the figure, and performs an electrophotographic image forming process in the order of charging, exposure, development, transfer, and cleaning. In this embodiment, the charging is performed by the charging charger 3 which applies a high voltage of several hundreds to several thousand volts to the conductive roll. In addition, a method of applying a high voltage to a charge wire such as a gold wire applied to a tungsten wire can also be used.

The photoreceptor for plate making of the present invention has a surface hardness of J
Those having a pencil hardness of 6H or more specified by IS K 5400 are preferably used. The photoreceptor has a photoconductive layer provided on a conductive substrate, and the photoconductive layer may be a function-separable two-layer system having a charge generation ability and a charge transport ability, or may be a single-layer system. A conventionally known configuration having a surface hardness of 6H or more or a surface protective layer having a pencil hardness of 6H or more on the photoconductive layer may be used. For the surface protective layer, a commercially available hard coat resin that does not adversely affect the electrophotographic properties can be used. For example, a hydrolysis condensate of a polyfunctional organic silicon compound and the like can be mentioned.

In the exposure, the photosensitive member 1 is illuminated imagewise from a light source (not shown) in an optical path indicated by L1 in the figure, and the surface charge of the photosensitive member 1 disappears only in the irradiated portion, thereby forming an electrostatic latent image.
Subsequently, the developing roller 2 performs toner development. As a developing method, a conventionally known one-component developing method using only a toner, a two-component developing method using a toner and a carrier, and a magnetic or non-magnetic developing method according to whether or not the toner has magnetism can be applied.

The toner of this embodiment is for plate making,
The glass transition temperature (Tg) of the resin used to increase the physical strength of the resin component contained for the purpose of improving printing durability is set higher than that for plain paper. As the toner for plate making purposes, it is preferable to optimize the number of prints required for use as a printing plate, the printing machine used, and the like, particularly from the viewpoint of printing durability. Specifically, the binder resin used for the toner is preferably used. It can be controlled by Tg, degree of crosslinking, molecular weight distribution, copolymer composition and the like.

In the transfer, near the lowest point of the photoreceptor 1 after development, the toner adhered imagewise onto the photoreceptor 1 on the printing plate is transferred. A corona charger (not shown) for providing a transfer charge (not shown) from the back of the printing plate is provided below the cartridge A, and the toner applied imagewise by the developing roll is transferred to the printing plate. As the transfer means, in addition to the above-described corona transfer method, a known transfer method, for example, a bias roller transfer method or the like can be used.

In order to remove toner remaining on the surface of the photoreceptor 1 after the transfer, cleaning of the photoreceptor surface is performed by cleaning blades 51 and 52. A cleaning blade 5 whose tip is biased against the surface of the photoconductor;
Step 1 removes the toner remaining on the surface of the photoreceptor after transfer. Therefore, even if it cannot be completely removed, it is removed by the cleaning blade 52. As a material for the cleaning blade, a conventionally known material can be used. For example, resins or rubbers such as urethane, silicon, and Teflon can be used. Further, it is preferable that reinforcement or correction is made with a holder or a stay made of metal or the like so that pressure is uniformly applied over the entire length.

Further, the cleaning of the photoreceptor surface for removing the toner after the transfer may be performed by using a cleaning brush. The cleaning brush rotates a brush roller made of fine fibers having a diameter of several tens to several hundreds μm at a speed higher than the rotation speed of the photoconductor 1 to remove toner on the surface. Further, it is also effective to remove the toner that has not been completely removed by the cleaning brush by the cleaning blades 51 and 52 whose leading ends are biased and abutted on the surface of the photoconductor.

As the cleaning means, the above-described brush method and blade method may be combined, or the same method may be used in multiple stages. By arranging a plurality of cleaning units, a cleaning operation can be stably performed over a long period of time even when a single cleaning unit is disturbed.

Through the electrophotographic image forming process, a toner image is formed on the printing plate. Thereafter, heat fixing is performed in a fixing unit of the laser printer. Based on the information of the recognition tag 6 given to the cartridge A, fixing is performed at a fixing temperature set in advance for plate making. In this case, the fixing temperature is preferably set to be higher than the difference of Tg from the setting for plain paper in consideration of the Tg of the binder resin of the toner.

The switching of the fixing temperature can be dealt with by adjusting the amount of heat generated by a heating member, for example, a heating roll, a panel heater, or a hot air heater. For example, when a plurality of heating elements are used, the number of heating elements may be changed, or the current to be supplied may be controlled.

Depending on the configuration of the laser printer used, if there is a distance between the cartridge and the fixing unit,
The transport speed of the printing plate at each acting portion can be changed. That is, the amount of heat applied to the toner on the printing plate surface can be adjusted by switching the conveyance speed in the fixing unit between plate making and plain paper. In this method, the amount of heat generated by the heater can be constant.

The electrophotographic image forming apparatus used in the present invention is, specifically, a printer or a digital copying machine using laser light or LED light as a light source, or an analog copying machine using a white light source. Any cartridge type can be used regardless of the type.

Next, a printing plate according to the present invention will be described.
In the printing plate according to the present invention, the support can be a paper such as a resin-coated paper, a plastic film such as polyethylene terephthalate and the like, and a material obtained by sandwiching a metal such as iron, aluminum, and copper as a core material. It includes paper and plastic film to which these are attached. The thickness is preferably in the range of 0.1 mm to 0.5 mm. A support having a hydrophilic surface or a support provided with a hydrophilic layer is used. Examples of the hydrophilic layer include binders of natural or synthetic resins such as gelatin, gum arabic, waxes PVA (polyvinyl alcohol) and modified products thereof, latexes, acrylic resins, phenolic resins, and polymers such as styrene and vinyl chloride. Particles or organic pigments such as phthalocyanine, inorganic pigments such as silica, alumina sol, titanium oxide and zinc oxide, etc., to form a layer in the form of particles containing organic or inorganic particles having a particle diameter of 0.01 to 20 μm as a main component, or urethane. A resin or polyvinyl formal resin made porous, JP-A-9-86066, JP-A-9-86067,
A direct drawing type lithographic printing plate described in detail in JP-A-9-99662 can be used.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless departing from the gist of the invention.

Examples and Comparative Examples A cartridge of a commercially available process cartridge type laser printer was modified, the photosensitive member and the toner were replaced as follows, and two sets of cleaning blades were attached. The fixing unit removes a predetermined fixing heat roll, and newly adds a heating element of の of the wattage of the internal heating element, and controls the added heating element by a metal plate attached to a cartridge to be set. Modifications have been made to generate heat when the fixing unit is operated when the recognition tag for use is detected by checking the continuity.

[Photoconductor] A surface protective layer was formed on the surface of the photoconductor removed from the cartridge using a bisphenol Z-type polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.). A coating liquid of the same resin is applied to a flat plate and subjected to JIS K54.
It was 6H when the pencil hardness specified by 00 was measured.

[Toner] The Tg of the toner loaded in the cartridge was measured by a differential scanning calorimeter (manufactured by PerkinElmer) and found to be 60 ° C. A toner having a Tg of 75 ° C. was prepared according to a conventional method.

The above-mentioned modified platemaking cartridge is set in the modified laser printer,
An image was formed on a paper-based lithographic printing plate having a hydrophilic surface (Straight Master manufactured by Mitsubishi Paper Mills, Ltd.). When this was printed on a printing machine, 10
Good printed matter was obtained up to the 00th sheet.

Further, the same plate making was output continuously for 100 sheets. No difference was observed in the images from the first plate to the 100th plate and the printing results using the images.

Next, the image was formed on plain paper (Mitsubishi PPC paper N, manufactured by Mitsubishi Paper Mills) by replacing the cartridge with a predetermined cartridge that had not been modified. No change such as overfixing of the toner image portion was observed as compared with the output product of Example 1.

Subsequently, an image was formed on the lithographic printing plate. As compared with the plate making using the modified cartridge, the non-image portion was recognized to have a lesser degree of fogging.
When printing was carried out using this, a printed matter in which the image portion was gradually lost was obtained from about the 100th sheet, and almost all images were missing in the 1000th printed matter. In addition, when a similar plate was made continuously for 100 sheets, black spots were generated in the non-image area from several plates, and increased with the number of plates.
The result was not suitable for practical use as a printing plate.

[0037]

As described above, according to the image forming method of the present invention, an image having excellent printability is formed on a printing plate having a hydrophilic surface using a general-purpose process cartridge type printer or copier. This makes it possible to make a printing plate at a low cost with a simple operation of replacing a cartridge without introducing a dedicated plate-making machine. Further, since the surface hardness of the photoreceptor is high, it is possible to prevent the photoreceptor from being damaged and adversely affecting image formation even when used for plate making of a printing plate having a rough surface. In addition, by providing a plurality of cleaning means, the effect of cleaning in the electrophotographic image forming process is improved, and stable operation is performed for a long time. Thereby, the running cost related to image formation can also be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view illustrating an example of a cartridge according to an image forming method of the present invention.

[Description of Signs] 1 Photoconductor 2 Developing roller 3 Charging charger 6 Recognition tag 51 Cleaning blade 52 Cleaning blade

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) 9A001

Claims (5)

[Claims] 1. A process cartridge type electrophotographic image forming apparatus in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachable from an image forming apparatus main body. At least one selected from an electrophotographic photosensitive member, a toner, and a cleaning unit to be used is formed as a different individual cartridge, and an image is formed by replacing the cartridge according to a sheet onto which an image is transferred and / or an image forming purpose. Image forming method. 2. An electrophotographic image forming apparatus main body reads image forming condition information attached to the cartridge, and performs processing by changing at least one selected from a conveying speed and a fixing temperature according to the condition. Claim 1
2. The image forming method according to 1., 3. The image according to claim 1, wherein the paper onto which the image is transferred is a printing original having at least a hydrophilic surface, and the purpose of image formation is to make the printing original. Forming method. 4. The image forming method according to claim 1, wherein the electrophotographic photosensitive member used in the cartridge has a pencil hardness of 6H or more on the surface of the photosensitive member. 5. The image forming method according to claim 1, wherein a plurality of individual cleaning units are arranged as the cleaning unit used in the cartridge.