JPH01216374A - Printing device - Google Patents

Abstract

PURPOSE:To vary density according to the preference of a person who performs printing by providing a function for adjusting the density of printed matter by an electric means. CONSTITUTION:Printing information from an outside is received with a controller 9 and the printing information in the controller 9 is transmitted to an optical controller 3 as image information arrayed corresponding to the printing position of the printing paper 11. Meanwhile, printing density information included in the printing information is transmitted to a density controller 25 from the controller 9. A developing bias voltage is controlled corresponding to the transmitted printing density information in the density controller 25 through the sleeve 4a of a developing device 4 to determine the density of a developed image. In order to control the printing density, a method for controlling the potential of the surface of an image carrier 1 is mentioned. Thus, the printing density can be freely selected and the printed matter with the desired density can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing apparatus equipped with a mechanism for automatically adjusting print density using the printing principle of an electrophotographic process.

(Prior Art) Conventionally proposed printing apparatuses using electrophotography do not take into account the need to adjust the print density to a desired density. I used a machine to make copies and obtain paper with the appropriate density.

Also, as a method of adjusting the density of a copying machine, the density adjustment button is selected before copying and then the copy is made.The selection range is from 3 stages of dark, normal, and light to a stepless method with a movable lever. The method is known.

[Problem to be solved by the invention]

In conventional printing apparatuses, a user cannot freely select the print density based on a print command from a personal computer or the like.

Therefore, in order to obtain printed matter with the desired density, users had to use secondary means (copy shades) or used printed matter while being dissatisfied with the density.The present invention is intended to solve these dissatisfaction among users. It provides a very high quality printing device.

[Means to solve the problem]

In the present invention, a density adjustment function of printed matter is added by electrical means. It consists of a light control device that forms an image, a developing device that visualizes the latent image formed on the image carrier, and a density control device that receives print density information indicating print density from the outside and controls the developed density. It is characterized by

(2) The density control device is characterized in that the developed density is controlled by varying the developing bias-[pressure of the developing device.

[Embodiment] The configuration and features of a printing device according to the present invention will be explained below with reference to the drawings.

1 and 2 are diagrams showing a first embodiment, and FIG. 1 is a configuration diagram of a printing apparatus.

As a printing means, an image carrier 1 rotates in the six directions of arrows, and around the image carrier 1 there are a charging device 2, a light control device 3, a developing device 4. Density control device 25, transfer device 5, cleaning device +
ffj 6, an erase device 7, a fixing device 8 below the image carrier l, a control box 9 on the back side of the printing device, a power supply 10 near the fixing bag vrL8, and a printing paper as a paper feeding means. 11 is a stacker part 12 that can store a plurality of sheets, and a paper feeding device 14 and a paper registration roller 15 are arranged, which have the function of feeding printing paper 11 one sheet at a time by a feeding roller section 13 when requested, and as a discharging means, A fixing guide plate 16 below the fixing device 8,
A paper ejection roller 17 is arranged, and paper reversing device 18, first paper transport device 19, second paper transport device 20, third paper transport device 21 .
A conveyance guide plate 22 is arranged to guide the paper from the paper discharge roller 17 to the paper registration roller 15, and an exhaust fan 23 is also provided. Further, the above devices and the like are covered by an outer case 24.

The printing process by this apparatus will be explained below.

The image carrier 1 has a surface layer exhibiting semiconductor characteristics such that the electrical resistance of the irradiated portion decreases when irradiated with light.

The charging device 2 generates corona discharge by applying a high voltage of several thousand volts between a thin metal wire and a ground electrode.

Light control bag f! 23 employs devices such as semiconductor laser light, liquid crystal shutter arrays, and LED arrays, and has the function of converting the image information created in the control box into optical signals (light ON/OFF signals) and outputting them. are doing. When the image carrier l is rotated at a constant speed in a state in which external light is blocked by the exterior case 24 and the inside of the case is dark, the charging device 2 charges the surface of the image carrier.

Furthermore, when the charged photoreceptor 1 is irradiated with light according to image information from the light control bag W13, the irradiated portion becomes an electrical conductor and a latent image is formed. The developing device 4 has toner, applies a developing bias voltage through the sleeve 4a, brings the toner into contact with the latent image portion, and forms a developed image on the surface of the image carrier.

On the other hand, the printing paper 11 stored in the stacker part 12 provided in the paper feeder 14 is sent out by the delivery roller part 13 and is developed by the developing device 4 which is waiting at the position of the paper registration roller 15. The paper registration rollers 15 rotate in synchronization with the rotation of the image carrier l to which toner has adhered, and feed the printing paper 11 toward the photoreceptor l. Like the charging device 2, the transfer device 5 is composed of a thin metal wire and a ground electrode, and has the function of charging the back side of the printing paper 11. The toner developed on the surface of the image carrier l is transferred to the printing paper 11. transfer is performed by being attracted to the surface of the While the transferred printing paper 11 passes through the fixing device 8, the toner on the surface is fixed to the printed paper 11.

FIG. 2 is a block diagram showing the flow of print information, in which the controller 9 receives print information from an external device such as a personal computer or a word processor.

The printing information in the controller 9 is sent to the light control device 3 as image information aligned so as to correspond to the printing position on the printing paper 11. On the other hand, print density information included in the print information is sent from the controller 9 to the density control device 25. The density control device 25 controls the developing bias voltage via the sleeve 4a of the developing device 4 in accordance with the sent printing density information. Generally, in order to determine the density of the developed image described above, if there is a large difference between the potential on the surface of the image carrier 1 and the potential on the sleeve 4a applied by the developing bias voltage, then
It is known that as the amount of toner added to the image carrier l increases, the density of the developed image increases.

Therefore, in order to control the printing density, there are two methods: controlling the developing bias voltage as in the embodiment, and controlling the potential on the surface of the image carrier 1.

Next, the printing process when printing information including printing density information is actually sent will be explained.

The controller 9 receives print information from a personal computer or the like and sends it to the light control device 3 as image information.

On the other hand, print density information is sent to the density control device 25. The density control device 25 sends the information to the print density information 25. Concentration control device 2
In step 5, the developing bias voltage is set based on the print density information.The image is printed as described above and gradually discharged from the fixing device 8. The printing paper 11 advances in the direction of arrow B along the fixing paper guide 16 in FIG. The paper is sent in from the paper reversing device 18 and then discharged from the window 24-1 of the outer case 24, thereby completing the printing process.

The second embodiment will be briefly explained using FIGS. 2 to 4.

FIG. 3 is a perspective view showing the second embodiment, and 1 to 25 are the same as those explained in FIG. 1. 27 is a front/back switching lever.

FIGS. 4(a) and 4(b) are diagrams showing image information, and the arrow ■ indicates the direction in which the printing paper 11 is sent out by the paper registration roller 15. There is a printing area 29 within the outer frame 28 of the printing paper 11 that indicates a printing area. Further, numeral 30 in the figure is an area indicating the binding margin after printing. The binding margin 27 will be explained next in the actual printing process in the paper traveling direction.

When text or figure information to be displayed with emphasis on one page enters the controller of the printing device as print density information from a personal computer, etc., the controller 9 divides the printing process into two parts and prints. will be taken into consideration. The first print is temporarily placed in the printing area 29 with a binding margin 30 as image information showing normal density as shown in FIG. 4(a). Next, the image information is sent to the optical control device @3. On the other hand, print density information indicating that the print density is normal is sent to the density control device 25. In the concentration control device 25,
Set the developing bias voltage.

Next, it is printed as described above and is gradually discharged from the fixing device 8. The printing paper 11 advances in the direction of arrows B and C. Next, the front/back switching lever 27 is rotated in the direction of the arrow by a command from the controller 9.
Stop at -1. Therefore, the printing paper 11 moves in the direction of the arrow E, and while correcting the inclination of the printing paper 11 by the first paper transport device 19, the second paper transport device 20, and the third paper transport device 21, the printing paper 11 moves in the direction of the arrows F and G. Then, the second printing process begins in the 0th order, where the paper is fed to the paper registration rollers 15.

As shown in FIG. 4'(b), the characters or figures to be emphasized are first sent to the light control device 3 as image information.The information to be emphasized in the 0th order, that is, the print density information indicating that the print density is the maximum, is sent to the light control device 3 as image information. Send to 25th. In the density control device 25, the developing bias voltage is set.Next printing is performed, and the printing paper 11 advances in the directions of arrows B and C. At this time, the front/back switching lever 27 rotates in the opposite direction to the arrow direction and stops at the position shown by the solid line. Therefore, the printing paper 11 advances in the direction of the arrow 11 and is sent to the paper reversing bag ra18.
Printing is completed by ejecting from 4-1.

FIG. 5 is a block diagram of the concentration control device 28.

A plurality of bits of print density information sent from the controller 9 is converted into an analog signal by a DIA conversion circuit and input to the electronic volume 29. The output of the electronic volume 31 is input to the high voltage generation circuit 30, where it is converted to a reference voltage level, thereby making it possible to vary the level of the developing bias voltage.

[Effects of the invention J.

As described above, according to the present invention, the density can be changed according to the preference of the person doing the printing, so if this printing yt setting is used, it is possible to print uniquely, and it is possible to avoid printing that is too dark as before. There is no need to worry about printed matter or, conversely, that the printed matter is too light.

Furthermore, by changing the density, it is possible to print with a lower density on previously submitted prints (for example, test prints), which can reduce the consumption of toner, which is a consumable item, and reduce running costs. There is also a ripple effect of lower prices.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention. FIG. 2 is a block diagram showing the first and second embodiments of the present invention, FIG. 3 is a perspective view showing the second embodiment of the present invention, and FIG.
Figures (a) and (b) are diagrams showing image information showing a second embodiment of the present invention. FIG. 5 is a block diagram of the concentration control device 25. l... Image carrier 3... Light control device 4... Developing device 9... Controller 11... Printing paper 25... Density control device and above Applicant: Seiko Epson Corporation

Claims (2)

[Claims] (1) In a printing device having a printing means using an electrophotographic process, an image carrier, a light control device for forming a latent image of image information on the image carrier, and a latent image formed on the image carrier What is claimed is: 1. A printing apparatus comprising: a developing device that visualizes the image; and a density control device that receives print density information indicating print density from the outside and controls the developed density. (2) The printing apparatus according to item 1, wherein the density control device controls the developed density by varying the developing bias voltage of the developing device.