JPS58127951A - Electrostatic printing method - Google Patents

Abstract

PURPOSE:To prevent the waste of printing masters and to prevent economical losses by providing stages for forming toner images on a photoreceptor by uniform electrostatic charging, image exposure and developing and performing test printing by transferring and fixing the images onto transfer materials. CONSTITUTION:An electrostatic printing method is characterized by starting a test printing stage without executing printing stages a-i continuously. The toner images formed on photosensitive paper 10 by the stages a-c are transferred onto transfer paper 11 and are further fixed; thereafter, the paper is discharged to the outside of the machine. Then, prior to printing, samples can be obtained without making the paper unreusable, and printing masters can be formed by evaluating the grade of the sample picture images, whereby the waste of the printing masters is prevented and economical losses are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing method applying the principles of electrophotography, and particularly to an electrostatic printing method having a test printing step for obtaining printed matter with a desired image quality.

Printing by electrophotography has been known for a long time. For example, U.S. Pat.
There are electronic printing devices, etc. This is done by forming a powder image on a photoconductive plate and fusing or fixing it by electrostatic photography, and then forming a non-photosensitive insulating image figure, that is, a printing master, on the photoconductive plate. The printing master is uniformly charged and then evenly irradiated with light. Thereby, the charge is retained only on the non-photosensitive image areas and discharged on the photosensitive areas, so that a charged powder is deposited on the partially exposed plate to form a powder image. This is a method of transferring onto a suitable image support, and the above steps are repeated.

In particular, Japanese Patent Publication No. 45-1554 discloses a device as shown in FIG. In FIG. 1, reference numeral 1 denotes a rotating drum, which has a holding claw on its side surface and supports the photosensitive paper 10. As shown in FIG.

A cleaning device 8, a charger 4, a uniform exposure lamp 15, a developing device 5, a transfer corotron 6, an infrared fixing device 7 for fixing the toner image on the photosensitive paper 10, etc. are arranged in four concave spaces surrounding the rotating drum 1. has been done.

To create a print master, after the photosensitive paper 10 is wrapped around and supported by the drum 1Vc, it is charged by the charger 4, and the document on the document table 6, which is further illuminated by the document illumination lamp 14, is transferred to the photosensitive paper through the projection lens 2. 10 to form an electrostatic latent image. Next, the latent image is developed by a developing device 5, and the toner image is fused and fixed onto photosensitive paper 10 by an infrared fixing device 7, thereby forming a printing master.

Electrostatic printing of a large number of sheets using such a printing master is performed as follows. The printing master with the toner image on the photosensitive paper is charged with a charger 4 and further with a monolithic light lamp 1
6, the entire surface is illuminated uniformly.

The charge on the uniformly charged photosensitive paper 10 is flushed away by the uniform light, leaving only the toner image portions that are insensitive and non-photoconductive. Therefore, a printing master is formed in which only the toner image portion has an electric charge, and is visualized by the developing device 5. Next, the transfer paper 11 is sent to the transfer section in synchronization with the rotation of the rotary drum 1, and the toner image on the print master is transferred to the transfer paper by the transfer corotron 6, and then becomes a fixed image by the fixing device 9. Guided by, obtain a copy. The remaining toner on the print master after transfer is cleaned by the cleaning device 8, and -th print cycle is completed.

Incidentally, it is also possible to use the developing device 5 as a cleaning/developing device as described in Japanese Patent Application No. 55-116777. Thereafter, the printing cycle is repeated as many times as the number of copies required.

However, the image quality of the copy obtained by the above-mentioned method reflects both the electrophotographic characteristics up to the creation of the print master and the electrostatic printing characteristics during printing, so the image quality of this copy is lower than that of conventional electrophotography. Compared to the copy image product JX obtained by law,
It becomes much more difficult to control. For example, factors that determine the image quality of a printing master include the amount of charge, the amount of image exposure, the toner content of the developing machine, and the pressure voltage.

For example, the image quality of a copy in the printing process varies depending on the amount of charge during printing, the amount of uniform light across the entire surface, the toner content of the developing machine, the bias voltage, and the like. Therefore, if you try to obtain a faithful copy of the original using this electrostatic printing method,
It is extremely difficult to use these many control factors wisely.

Furthermore, when making a copy from an original using this method, if the desired image quality is not obtained, the print master created during the electrostatic printing process will be wasted, which is time-consuming and economical. It will also be a big loss.

It is an object of the present invention to provide an electrostatic printing method that eliminates these drawbacks and allows desired copies to be obtained quickly.

The present invention is characterized by providing a trial printing process in addition to the electrostatic printing process described above. Particularly, the electrostatic printing is performed based on a print start signal when the image quality by the trial printing is above an acceptable level. The percentage of the process *1 is expressed as a percentage.

The above-mentioned tolerance refers to the level required by the user, such as the degree of misalignment of the copy, the density of the image, the degree of capillarity in the background, the reproduction of gradation like that of a photograph, etc. Good too.

The present invention will be explained below based on the drawings.

In Figure 2, the printing process surrounded by the dashed line is
This is a part of the conventional printing process described in No. 1554 and the like.

In this process, the process indicated by lsk is
-11677/i. In this process, AWD is a stone process that creates a master for electrostatic printing, and EWI is a process that uses the master mentioned above to obtain electrostatic prints.In this process, image exposure is not performed, so high-speed Electrostatic printing becomes possible. Further, when a large number of printed materials are required, the steps on the drum 1 are continuously operated in a loop through the steps J and lc, and electrostatic printing is performed.

Factors that determine the quality of printed matter in this printing process will be explained.

First, the quality of the toner image on the photosensitive paper 10 that is to become a master is determined through steps a to C. If the image quality is poor, naturally the quality of printed matter obtained in subsequent steps will also be relatively poor. Therefore, if each step of charging a, image exposure b, and development C is not adjusted and controlled to an appropriate level, the image density may be low or stains may occur in the margins, for example.

Although not shown in this figure, how the original is set on the original stand 6 is also important. For example, if the original is set diagonally or too close to the edge, it will naturally appear on the photosensitive paper 10. The resulting toner image is also considerable. Therefore, if we continue the process after e,
The quality of the printed matter obtained as a result of electrostatic printing, that is, the quality corresponding to the master mentioned above, for example, the image density is low,
The printed matter will be very unsatisfactory, with smeared margins and crooked prints.

Moreover, according to the method disclosed in Japanese Patent Publication No. 1554/1984, the result of this defect is only recognized after all steps a to 1 are completed, and during this period, a considerable amount of time is wasted and cannot be ignored. Moreover, in steps a to d, a printing master having a fixed toner image is formed on the photosensitive paper 10, so the photosensitive paper 10 cannot be reused, resulting in a huge economic loss. . The purpose of the present invention is to eliminate this drawback by providing a trial printing process, obtaining sample images prior to printing, evaluating whether the quality is satisfactory, and making corrections or adjustments as appropriate. By starting printing in response to a print signal, wasteful consumption of the photosensitive paper 10 is eliminated and high-quality printed matter is reliably provided promptly.

The present invention is characterized in that the printing steps a to 1 are not carried out consecutively, but after the development of step C is completed, the process moves to a test printing step surrounded by a frame with a dashed-dotted line. Transferring the toner image formed on paper 10 to transfer paper 11,
It is further fixed and discharged outside the machine. Looking at the quality of the sample image that has been improved through this step, it is determined whether to continue with the steps from d onwards and perform the printing process as is, or to adjust each step to correct the quality. Of course, after providing the sample through the test printing process, it is desirable to clean the residual toner image on the photosensitive paper 10 through processes r and s in preparation for the next process. In addition, this static elimination cleaning for r and s does not require a dedicated device;
As disclosed in No. 1907, cleaning may be carried out at the 102nd rotation of the drum by using a developing machine which also serves as a cleaning device. As mentioned above, by adding a test printing process to the printing method disclosed in Japanese Patent Publication No. 45-1554,
It is now possible to perform the A'-p steps of a, b, C, p@r, and 8 on the drum 1, making it possible to print samples before printing without making the photosensitive paper 10 unusable. becomes.

After evaluating the quality of this sample image, a print master is formed by charging, image exposure, development, and plate making fixing based on the printing start signal that has been appropriately modified or adjusted. The electrostatic printing method of the present invention carries out the printing process consisting of:

Sample l1ii obtained by the above-mentioned test printing process
If my image quality is below an acceptable level, I will have to correct the image quality. Specifically, this may be an instruction to correct the image density in a higher direction, or a dial adjustment. More advanced modification requests may be considered, for example, to prevent the margin from becoming dirty or to increase the density of the halftone portion of the image. In accordance with these correction control instructions, the present invention can correct the image quality to an acceptable level or higher by adjusting the amount of charge, the amount of light, and the developing bias. After instructing correction control on such a sample image, it is desirable to carry out the test printing process again to confirm the effect of the correction control.

The test printing process described above can be repeated many times depending on the situation. Therefore, it is also possible to issue a selection instruction to enter the printing process directly without going through the trial printing process of the present invention. Therefore, it is preferable that an apparatus for carrying out the method of the present invention be provided with a selection button for selecting whether or not to perform trial printing, and the signal for determining whether or not to perform trial printing may also be used as the above-mentioned print start signal.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the electronic printing device, and the third...
Original table, 4...Charger, 5...Developer, 6...
Transfer corotron, 7... Fixing device, 8... Cleaning device, 9... Print fixing device, 10... Photosensitive paper,
11... Transfer paper, 12... Output tray, 15...
Uniform light lamp 14... Original illumination lamp. Agent Patent Attorney (8107) Kiyoshi Takashi Sasaki (and 6 others) si diagram

Claims (1)

[Scope of Claims] In a method of electrostatic printing, in which an electrostatic latent image is formed on a photoreceptor by electrophotography, developed and fixed to form a fixed toner image on the photoreceptor, uniform charging is performed. , a step is provided in which a toner image is formed on the photoreceptor by image exposure and development, and then transferred and fixed onto a transfer material to perform a test print. Based on the result of this test print step, a print start signal is given, and the toner image is charged and imaged. An electrostatic printing method characterized by forming a printing master by exposing, developing, and fixing by plate making, and then printing by performing charging, monomorphic light, development, transfer, and fixing on this printing master.