JP2530808B2 - Serial type electrophotographic printer - Google Patents

Description

The present invention relates to a printer to which electrophotographic technology is applied, and more particularly to a serial type electrophotographic printer using a belt-shaped photoconductor.

[Conventional technology]

So-called electrophotographic printers to which electrophotographic technology is applied are known, and line type printers are the mainstream for high-priced models of this electrophotographic printer.

On the other hand, low-priced models are mainly serial type printers, and one example thereof is disclosed in Japanese Patent Laid-Open No. 59-192586.

This serial type electrophotographic printer is equipped with a photosensitive member which rotates at a constant speed, and a recording means comprising a charging device, an optical head, a developing device and the like arranged along the peripheral surface of the photosensitive drum, mounted on a carriage. While reciprocating in a direction orthogonal to the feeding direction of the recording paper, a toner image is formed on the photoconductor and a toner image is transferred to the recording paper to obtain a desired recorded image on the recording paper. It is configured.

[Problems to be solved by the invention]

However, in the above-mentioned conventional serial type electrophotographic printer, it is necessary to move the carriage equipped with the recording means including the photoconductor, the charger, the optical head, and the developing device at a high speed, so that the mechanical inertia becomes large. In the actual operation, there was a problem that a drive source such as a motor having a large drive capacity was required to move the carriage.

Further, for the convenience of recording by rotating the photoconductor only in one direction, when the carriage reciprocates, recording can be performed only when the carriage moves in one direction, for example, in the forward direction. The effective time for recording is short,
There is also a problem that it is difficult to realize high-speed recording.

As another conventional serial type electrophotographic printer,
There are some types that use a belt-shaped photoconductor, but since the belt-shaped photoconductor is constantly brought into contact with the recording paper and the belt-shaped photoconductor is moved even when the toner image is transferred, it is possible to obtain a high-quality recorded image. There was a problem that it was difficult.

The present invention has been made to solve such a problem, and does not require a driving source having a large driving capability, enables high-speed recording, and is a serial electronic device capable of obtaining a high-quality recorded image. The purpose is to realize a photographic printer.

[Means for solving problems]

To achieve this object, the present invention comprises a platen roller that supports and conveys recording paper, and a photosensitive layer provided on the surface of a conductive support, and conveys the recording paper in opposition to the platen. An endless belt-shaped photosensitive member arranged so as to circulate in a direction orthogonal to each other, a drive source for cyclically moving the belt-shaped photosensitive member, and the platen for forming a toner image on the belt-shaped photosensitive member. And a charging unit, an optical head, and a developing unit, which are arranged on the opposite side to the charging unit, the optical head, the developing unit, and the platen, and the belt-shaped photosensitive member is moved in parallel with the recording sheet. And a power source switching unit that switches the potential applied to the conductive support of the belt-shaped photoreceptor during the toner image formation and the toner image transfer. In a state where the entire light body was separated from the recording paper, while circulating moving the photosensitive belt,
A toner image is formed by the charging unit, the optical head, and the developing device, and the entire belt-shaped photosensitive member is moved to the platen side by the movable unit to bring the portion where the toner image is formed into contact with the recording paper, and the power source is supplied. After the toner image is transferred to the recording paper by switching to the potential for toner image transfer by the switching means, the step of feeding the recording paper by the rotation of the platen is repeated to form a recorded image on the recording paper. Characterize.

[Action]

According to the present invention having the above-described configuration, the toner image is formed on the belt-shaped photoconductor while the belt-shaped photoconductor is circulated and moved while being separated from the recording paper, and the toner image is located at a position facing the recording paper. And to write an electrostatic latent image for forming the next toner image in a portion of the belt-shaped photoreceptor other than the area where the toner image is formed, and thereafter, the movement of the belt-shaped photoreceptor is stopped, The belt-shaped photoconductor is brought into contact with the recording paper, and the potential applied to the conductive support of the belt-shaped photoconductor is switched to transfer the toner image to the recording paper. Then, after the transfer, the belt-shaped photosensitive member is moved away from the recording paper to form a toner image and write an electrostatic latent image, and the recording paper is fed. Get image record.

Therefore, according to this, since only the belt-shaped photosensitive member is moved, it is possible to use a driving source having a small driving ability and to form an electrostatic latent image for forming a toner image and the next toner image. Since writing and writing can be performed at the same time, high-speed recording is possible, and since the belt-shaped photoconductor is separated from the recording paper when the toner image is formed, the recording paper is not stained and high-quality recording can be realized.

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a serial type electrophotographic printer according to the present invention, and FIG. 2 is a side view of FIG.

In the figure, 1 is a recording sheet, 2 is a conductive platen roller, and the recording sheet 1 is supported in close contact with the platen roller 2. As shown in FIG.
The recording paper 1 is fed in the direction of arrow B by rotating in the direction.

3 is a belt-shaped photosensitive member formed endlessly. The belt-shaped photosensitive member 3 is composed of a flexible conductive support 4 and a thin photosensitive layer 5 such as OPC provided on the surface thereof. And pulleys 6a, 6 so that they face the platen 2.
The pulley 6a is wound around b and has a drive source (not shown).
For example, by rotating the motor in a predetermined direction by a step motor, it is circularly moved in the direction of arrow C shown in FIG.

Reference numeral 7 denotes a power source switching means connected to the conductive support 4 of the belt-shaped photoconductor 3, which has a movable contact 8a and fixed contacts 8b and 8c, and is movable contact 8a at the time of forming and transferring a toner image described later. Are switched to apply a potential corresponding to the formation or transfer of the toner image to the conductive support 4.

Reference numeral 9 denotes a charging unit for uniformly charging the photosensitive material 5 of the belt-shaped photosensitive member 3, and a charging roller composed of a semiconductive brush is used. A charging voltage is applied to the charging unit 9. There is.

Reference numeral 10 denotes an optical head. This optical head 10 is a light source 11 such as an LED array in which a plurality of light emitting elements are linearly arranged, and the light source 1
The optical spot 1 is the thin film photosensitive material 5 of the belt-shaped photosensitive body 3.
And a lens system 12 for forming an image on.

13a, 13b, and 13c are developing units that store color toners of different colors. The developing units 13a to 13c, the optical head 10, and the charging unit 9 are located on the opposite side of the platen roller 2. Is provided along the belt-shaped photoconductor 3.

14 is an actuator, 15 is a base connected to the actuator 14, and the pulleys 6a, 6b are mounted on the base 15.
A belt-shaped photoconductor 3 is mounted together with the belt-shaped photoconductor 3 by moving the base 15 in the directions of arrows D and E shown in FIG. 2 by the actuator 14.
The recording sheet 1 supported by the recording medium 1 comes in contact with and is separated from the recording sheet 1.

Reference numeral 16 is a fixing device provided in the conveying path of the recording paper 1.

 Next, the operation will be described.

First, in the case of monochromatic recording, the belt-shaped photoconductor 3 is separated from the recording paper 1 at the time of toner image formation, and the movable contact 8a of the power source switching means 7 is connected to the fixed contact 8b. A potential for toner image formation is applied to the conductive support 4 of FIG.

In this state, when the pulley 6a is driven by a drive source (not shown), the belt-shaped photosensitive member 3 moves in the direction of arrow C at a constant speed. With this movement, the photosensitive layer 5 of the belt-shaped photosensitive member 3 is uniformly charged, and subsequently the optical head
By 10, an electrostatic latent image corresponding to the recorded image is written on the thin film photosensitive layer 5.

This electrostatic latent image is developed by the movement of the belt-shaped photoreceptor 3
The toner is transferred to the position of 13a and is developed with the toner supplied from the developing device 13a to form a toner image.

The toner image thus formed on the belt-shaped photoconductor 3 is sent to a position opposite to the recording paper 1 supported by the platen roller 2 as the belt-shaped photoconductor 3 further moves in the direction of arrow C. After that, the movement of the belt-shaped photoreceptor 3 is stopped.

The area where the toner image is formed once corresponds to the recording area within the width of the recording paper 1 and is, for example, the range of 1 shown in FIG.

While the toner image is being sent to the position opposite to the recording paper 1, an electrostatic latent image for forming the next toner image is written by the optical head 10 on the other area of the belt-shaped photoconductor 3. .

Now, when the movement of the belt-shaped photoconductor 3 is stopped as described above, the actuator 15 moves the base 15 in the direction of the arrow D, whereby the portion of the belt-shaped photoconductor 3 on which the toner image is formed is recorded. When the paper 1 is touched, the movable contact 8a of the power source switching means 7 is switched from the fixed contact 8b to the fixed contact.
Connect to 8c.

As a result, the conductive support 4 of the belt-shaped photoconductor 3 is provided with a transfer potential in place of the toner image forming potential, and thus is formed on the surface of the photosensitive layer 5 of the belt-shaped photoconductor 3. The toner image is transferred to the recording paper 1, and after transfer, the base 15 is moved in the direction of arrow E by the actuator 14 to separate the belt-shaped photoconductor 3 from the recording paper 1, and the movable contact 8 of the power supply switching means 7 is again fixed contact. Connected to 8b, the conductive support 4 is supplied with a potential for toner image formation.

In this way, when the transfer of one line is completed, the platen 2
Is rotated by a certain amount in the direction of arrow A by a drive source (not shown), the recording paper 1 is fed by one line in the direction of arrow B, and the belt-shaped photosensitive member 3 is again moved in the direction of arrow C.

During this movement, the electrostatic latent image already written on the thin film photosensitive material 5 of the belt-shaped photosensitive member 3 is developed by the developing device 13a and sequentially formed into a toner image, and the area where the previous transfer is performed is the charging means. It is recharged by 9 and subsequently the writing of the electrostatic latent image is carried out by the optical head 10.

Then, when the toner image is sent to a position facing the recording paper 1, the movement of the belt-shaped photoconductor 3 is stopped and the toner image is transferred to the recording paper 1 in the same manner as described above.

By repeating such a process, the recording paper 1
A recorded image composed of the transferred toner image is formed on the upper side, and the recorded image, that is, the toner image is transferred to the platen roller 2
Is fed to the fixing device 16 together with the recording paper 1 moving in the direction of arrow B, and is fixed on the recording paper 1 by the fixing device 16.

As described above, a serial monochromatic recorded image is obtained.

Next, the case of performing color recording will be described. When recording with two colors, two developing devices 13a and 13b are used.

In this case, first, a toner image of the first color by the toner of the developing device 13a is formed on the photosensitive layer 5 of the belt-shaped photoconductor 3 by the same procedure as in the case of the monochromatic recording, and this toner image is made to face the recording paper 1. While being sent to the facing position, an electrostatic latent image for forming a second color toner image is written on the photosensitive layer 5.

After that, the movement of the belt-shaped photoconductor 3 is stopped, the belt-shaped photoconductor 3 is brought into contact with the recording paper 1 to transfer the toner image of the first color, and then the belt-shaped photoconductor 3 is attached to the recording paper 1. Separate them.

Here, the belt-shaped photoconductor 3 is again moved in the direction of arrow C, but at this time, the recording paper 1 is not fed in the direction of arrow B,
The portion where the toner image of the first color is transferred is left facing the belt-shaped photoconductor 3.

Then, the electrostatic latent image already written on the photosensitive layer 5 of the belt-shaped photoconductor 3 is developed by the developing device 13b to form a toner image of the second color, and the toner image of the second color is formed on the recording paper. 1, while writing the electrostatic latent image for forming the toner image of the next first color during that time, the belt-shaped photosensitive member 3 is brought into contact with the recording paper 1 and After the toner image of the second color is transferred to the line on which the toner image of the first color is transferred, the belt-shaped photoconductor 3 is separated from the recording paper 1, and the recording paper 1 is fed in the direction of arrow B by one line.

By repeating the above steps and fixing the toner image on the recording paper 1 by the fixing device 16, a color recording image of two colors can be obtained.

In the case of recording with three colors, three developing devices 13a, 13b, 13c are used, and the first color is printed on the same line of the recording paper 1 in the same process as described above.
By sequentially transferring the toner images of the second and third colors,
It is possible to obtain color recording images of three colors.

When performing color recording, in addition to the above-described method, the developing areas of the developing devices 13a, 13b, 13c are divided in the width direction of the belt-shaped photoconductor 3 and the developing devices 13a, 13b, 13c are divided. It is also possible to simultaneously form the toner images by the above-mentioned method and transfer these toner images to the recording paper 1 at the same time, and then move the recording paper 1 by one color. Color recording images can be obtained by overlapping on the recording paper 1.

In the above-described embodiment, the belt-shaped photoconductor 3 is used as the recording paper 1.
Although the actuator 14 is used as the movable means for contacting and separating from each other, it is also possible to use a means such as a cam.

〔The invention's effect〕

As described above, according to the present invention, the endless belt-shaped photosensitive member including the conductive support and the thin film photosensitive material is provided so as to face the platen roller that closely supports the recording paper, and is applied to the conductive support. A power supply switching means for switching the electric potential between the time of toner image formation and the time of transfer is provided, and a charging means, an optical head, and a charging head are provided at a position opposite to the platen roller.
And a developing device are arranged, and these charging means, optical head,
And a toner image formed on the surface of the thin film photosensitive material of the belt-shaped photoconductor by the developing device, is sent to a position opposite to the recording paper by the movement of the belt-shaped photoconductor, and then the belt-shaped photoconductor is stopped to stop the toner. Since the image is transferred to the recording paper, only the belt-shaped photoconductor moves, so the mechanical inertia is small, so a drive source with a large drive capacity as in the past is not required, and it is small. The effect that a drive source of drive capacity can be used is obtained.

In addition, since the next electrostatic latent image is written while the toner image is formed and sent to the position facing the recording paper, the effective time for recording becomes longer, and the effect that high-speed recording can be realized is obtained. Since the toner image is brought into contact with the recording paper by moving the entire belt-shaped photoconductor in parallel with the recording paper, the toner image is not disturbed, and an excellent toner image can be transferred.

Further, since the belt-shaped photoconductor is moved away from the recording paper when the toner image is formed and the recording paper is fed, the recording paper is not contaminated when the toner image is formed or the recording paper is fed. Therefore, there is also an effect that a high-quality recorded image can be obtained, and since the potential of the conductive support of the belt-shaped photoconductor is switched during toner image formation and transfer, it is only necessary to ground the platen roller. Also, there is an advantage that it is possible to expect an improvement in safety and a reduction in cost because it is not necessary to apply a potential.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a serial type electrophotographic printer according to the present invention, and FIG. 2 is a side view of FIG. 1: recording paper, 2: platen roller, 3: belt-shaped photoreceptor, 4: conductive support, 5: thin film photosensitive material, 6a, 6b: pulley, 7: power supply switching means, 9 ... charging means, 10: optical head , 13a to 13c: developing device,
14: Actuator, 15: Base, 16: Fixer

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-50-122244 (JP, A) JP-A-53-141634 (JP, A) JP-A-56-144441 (JP, A) JP-A-58- 105268 (JP, A) JP 58-90654 (JP, A) JP 53-120441 (JP, A) JP 59-31982 (JP, A) Actual development Sho 58-113065 (JP, U) Actual development Sho 58-113056 (JP, U)

Claims (2)

(57) [Claims] 1. A platen roller which supports and conveys a recording sheet, and a photosensitive layer provided on the surface of a conductive support, and which faces the platen in a direction orthogonal to the conveying direction of the recording sheet. An endless belt-shaped photosensitive member arranged so as to circulate, a drive source for circulating the belt-shaped photosensitive member, and a position opposite to the platen for forming a toner image on the belt-shaped photosensitive member. A charging unit, an optical head, and a developing unit that are arranged; a moving unit that moves the belt-shaped photosensitive member in parallel with the recording sheet between the charging unit, the optical head, the developing unit, and the platen; Power supply switching means for switching the potential applied to the conductive support of the belt-shaped photoreceptor during toner image formation and toner image transfer is provided, and the belt-shaped photoreceptor as a whole is described by the movable means. While being separated from the paper, the belt-shaped photosensitive member is circulated and moved, while being charged by the charging means, an electrostatic latent image is written by an optical head, and the electrostatic latent image is recorded as a toner image by a developing device. While feeding to the position facing the paper, the next electrostatic latent image is written, and the movable means moves the entire belt-shaped photoconductor to the platen side so that the portion on which the toner image is formed contacts the recording paper. Then, the power source switching means switches the potential to toner image transfer potential to transfer the toner image onto the recording paper, and then the entire belt-shaped photoreceptor is separated from the recording paper, and the platen is rotated to feed the recording paper. A serial type electrophotographic printer is characterized in that a recording image is formed on the recording paper by repeating the step of forming the toner image of the next electrostatic latent image. 2. A serial type electrophotographic printer according to claim 1, wherein a plurality of developing devices containing toners of different colors are arranged along the belt-shaped photoconductor.