JPH0392871A - Feeding method for recording medium - Google Patents

Abstract

PURPOSE:To allow a carrying member to surely grasp recording paper by feeding the recording medium toward the carrying member so that the recording medium comes to a grasp position when the carrying member reaches the recording medium grasp position. CONSTITUTION:When a detecting means 27 detects that the carrying member 24 reaches the grasp position of the recording medium 25, the feeding means 26 is driven to feed the recording medium 25 toward the carrying member 24 so that the recording medium 25 comes to the grasp position. Since the leading edge of the recording medium 25 is in the position where it is to be grasped when the grasp element of the carrying member 24 moves to the grasp position, the carrying member 24 surely grasps the leading edge of the recording medium 25 and carries it to the recording position of a recording means 23.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems Action Examples Effects of the Invention [Summary] Grasping and conveying a recording medium Regarding an image forming apparatus in which a conveyance member is caused to feed out a recording medium, grip it, and convey it to a recording position of a recording means, the recording medium is fed out in synchronization with the position of the conveyance member, The purpose of the present invention is to enable the conveying member to reliably grip the recording paper, and includes: a conveying member that grips and conveys the recording medium to a position where the recording means performs recording; In an image recording apparatus equipped with a feeding means for feeding out, a detection means for detecting the position of the conveyance member is provided, and when the conveyance member reaches a gripping position of the recording medium according to a detection output of the detection means, the above-mentioned The recording medium is fed out to the conveying member by driving the feeding means so that the recording medium reaches a gripping position. [Industrial Field of Application] The present invention relates to an image forming device in which a conveying member that grips and conveys a recording medium feeds out the recording medium, grips it, and conveys it to a recording position of a recording means. The present invention relates to a method for feeding out a recording medium in which the recording medium is fed out in synchronization with the position.

Conventionally, image recording devices using an electrophotographic method, particularly color printers equipped with a plurality of photosensitive drums, each of which is equipped with a charger, an exposure optical system, a developer, a transfer device, and a cleaner, have been used to record color originals. A color-separated optical image is formed on each photosensitive drum by an exposure optical system, and then developed with color toner of each color, onto a recording medium, that is, recording paper, which passes through the toner image transfer position of each photosensitive drum. Color printing is performed by overlapping transfers and then fixing them.

Such color recording devices have been disclosed in Japanese Patent Application Laid-open Nos. 53-74036 and 1983-968305I, but in recent years, with the advancement of digital technology, originals have been recorded using charge-coupled devices. (CCl)) A method was developed in Japanese Patent Application Laid-Open No. 61 (1982) in which colors are separated and read using a sensor, processed digitally, and written on a photosensitive drum using a laser optical system.
It is disclosed in Japanese Patent No. 196268 and the like.

However, in a method in which a plurality of laser optical systems are provided for each color and the image is formed on the photosensitive drum C, one line in the sub-scanning direction is generated at the start of exposure for each optical system in the image transferred onto the recording paper. The size of the image of each color may differ in the paper feed direction because the scanning period tends to shift between each optical system.

Furthermore, due to the difference in the distance from the polygon mirror to the photosensitive drum surface, there is a drawback that the size of the image for each color tends to vary in the paper width direction as well.

As a result, there is a problem in that relative positional shifts occur for each color on the recording paper, resulting in deterioration of image quality. Furthermore, since the laser optical system uses a rotating mirror, an f-theta lens, and a cylindrical lens, there is a problem that the optical system becomes large and, as a result, the entire apparatus becomes large.

In addition, in these color recording devices, a belt-shaped dielectric film is rotated as a conveyance mechanism for the recording paper, and the recording paper is attracted to this belt by static electricity, and as the belt moves, the toner image is transferred to each photosensitive drum. I was passing the position.

When using such electrostatic adsorption force, if the equipment environment becomes highly humid, the electrical resistance of the recording paper decreases, which weakens the adhesion force against the dielectric film, making the belt's ability to hold the recording paper unstable. Become. Therefore, there is a problem in that a relative shift occurs for each color and the image quality deteriorates.

Therefore, in order to solve the above problems, an optical head consisting of a light emitting diode (LED) array and a condensing lens array was used as the optical system, and an optical head was used as the recording paper transport mechanism.
8 on the tip of the recording paper! 1. A color recording fi system using a conveying means that grasps and conveys the material in a large area, that is, a conveying member in which a long plate-like member is attached to a belt and a gripping element is attached to this plate-like member (Japanese Patent Application No. 1-79097) ) has been proposed.

By the way, in such a color recording device, since the leading edge of the recording paper is mechanically gripped, the recording paper is fed out in synchronization with the position of the first general feeding member, so that the conveyance member can reliably grip the recording paper. It is necessary to do so.

[Conventional technology]

FIG. 4 is a diagram illustrating an example of the prior art.

FIG. 4 shows an example of the configuration of a color recording device using four photosensitive drums. ,P. ．． I) c, P, are process units that print each color of yellow, magenta, cyan, and black, for example.

And process unit P. is a photosensitive drum]a, a charger 2a, an exposure device 3a, a developer 4a, a transfer device 5a, and a cleaner 6a; 4b,
It is composed of a transfer device 5b and a cleaner 6b.

In addition, the process unit PC includes a photosensitive drum 1c and a charger 2.
c,? The process unit 1-1) is composed of a photosensitive drum 1d, a charger 2d, an exposure device 3d, a developer 4d, a transfer device 5d and a cleaner 6d. Consists of.

When an instruction to start printing is given, a motor driven by an instruction from a control circuit (not shown) rotates the drive booth 11, causing the belt 10 to run at a constant speed in the direction of arrow A. Then, a voltage is applied to the charger l3 to charge the belt 10 made of a dielectric film such as Mylar. Further, the photosensitive drums 13 to Id rotate in synchronization with the running speed of the belt 10, and residual toner is cleaned by cleaners 68 to 6d, respectively. Then, voltage is applied to 1' according to instructions from the control circuit.
The cleaned surfaces of the photosensitive drums 1a to 1d are charged by the electric devices 2a to 2d. In addition, the control circuit is connected to each developing device 4a.
The developing rollers 4d to 4d are rotated and the developing bias is turned on.

When the control circuit is instructed to start printing, the control circuit moves the recording paper cassette 8
The recording paper 7 stored in the recording paper cassette 8 is fed out from the recording paper cassette 8, is brought into contact with a standby roller 9, and is kept on standby.

When the preparation for printing is completed, the standby roller 9 is driven to feed out the recording paper 7, and the recording paper 7 is attracted to the charged belt IO by electrostatic adsorption force, and the process unit P1
between the photosensitive drum 1a and the transfer device 5a.

Based on the timing of driving the standby roller 9, the control circuit moves the recording paper 7 to the process unit I-P. For example, a modulated light beam from an exposure device 3a using a laser light source is applied to the photosensitive drum la.
to form an electrostatic latent image one line at a time.

Toner supplied from the developing roller of the developing device 4a with the developing bias turned on as described above adheres to this latent image, and a yellow 1.toner image is developed on the photosensitive drum 1a.

Based on the timing of driving the standby roller 9, the control circuit measures the time it takes for the recording device 7 to be conveyed between the transfer device 5a and the photosensitive drum 1a, and then applies a voltage to the transfer device 5d and moves the photosensitive drum 1. The toner image formed on a is transferred to the recording paper 7.

Process unit P. The recording paper 7 onto which the yellow toner image has been transferred is carried between the photosensitive drum 1b and the transfer device 5b of the process unit P as the belt 10 runs.

The control circuit measures the time it takes for the recording paper 7 to reach the toner image transfer position of the process unit Pb based on the timing of driving the standby roller 9, and measures the time for the recording paper 7 to reach the toner image transfer position of the process unit Pb.
A modulated light beam from b is projected onto the photosensitive drum 1b, and an electrostatic latent image is sequentially formed line by line.

Toner supplied from the developing roller of the developing device 4b whose developing bias is turned on as described above adheres to this latent image, and a magenta toner image is developed on the photosensitive drum lb.

Based on the timing of driving the standby roller 9, the control circuit measures the time it takes for the recording paper 7 to be inserted between the transfer device 5b and the photosensitive drum 1b, and then applies a voltage to the transfer device 5b so that the photosensitive drum The toner image formed on lb is transferred onto recording paper 7.

The recording paper 7, onto which the magenta toner image has been transferred in the process unit P, is placed between the photosensitive drum Ic of the process unit P and the transfer device 5c as the belt 10 moves.

Based on the timing of driving the standby roller 9, the control circuit measures the time it takes for the recording paper 7 to reach the toner image transfer position of the process unit PC, and then activates the exposure device 3 using a laser light source.
The light beam l, which has been changed from c to #jj, is projected onto the photosensitive drum IC, and an electrostatic latent image is sequentially formed line by line.

Toner supplied from the developing roller of the developing device 4C with the developing bias turned on as described above adheres to this latent image, and a cyan toner image is developed on the photosensitive drum 1c.

The control circuit measures the time for the recording paper 7 to be carried between the transfer device 5c and the photosensitive drum IC based on the timing of driving the standby roller 9, and then applies a voltage to the transfer device 5C.
The toner image formed on the sensitive drum 1c is transferred to the recording medium 7.

The recording paper 7, onto which the cyan toner image has been transferred by the process unit Pe, is carried between the photosensitive drum ld and the transfer device 5d of the process unit 1/P4 as the belt 10 runs.

The control circuit measures the time for the recording paper 7 to reach the toner image transfer position of the process unit Pd based on the timing of driving the standby roller 9, and directs the modulated light beam from the exposure device 3d using a laser light source to the photosensitive drum. 1d, and the electrostatic latent image is projected one line at a time. Toner supplied from the developing roller of the developing device 4d whose developing bias is turned on as described above adheres to this latent image, and a black toner image is developed on the photosensitive drum 1d.

The control circuit measures the time it takes for the recording paper 7 to be conveyed between the transfer device 5d and the photosensitive drum 1d based on the timing of driving the standby roller 9, and then applies a voltage to the transfer device 5d.
The 1.color image formed on the photosensitive drum 1d is transferred onto the recording paper 7.

Process unit P. As the belt 100 runs, the recording paper 7 on which the black 1.toner image has been transferred is carried between the fixing roller and the pressure roller of the fixing device 12, and the transferred four-color toner image is fixed thereon.

The belt 10 is neutralized by the static eliminator l4, and the belt Kobe 13
is charged again. This is to ensure that the recording paper 7 is always attracted with a predetermined electrostatic attraction force.

[Problems to be Solved by the Invention] As described above, conventionally, the recording paper 7 is attracted to the belt 10 by electrostatic adsorption force and conveyed, but the electrical resistance value of the recording paper 7 is greatly affected by humidity. , generally l09 to 1
It changes within the range of 0.016Ω・CJ. When the humidity is relatively low, the electrical resistance value of the recording paper 7 is large and a sufficient amount of electric charge is applied to the recording paper 7, so that the recording paper 7 will not be misaligned after being attracted to the belt 10.

However, when the humidity increases, the electrical resistance of the recording paper 7 decreases, and the electrostatic adsorption force acting between the recording paper 7 and the belt 10 becomes weaker, so that the paper 7 is attracted to the belt 10 and then transported. Misalignment occurs during the process. Therefore, the process unit P. ,P. , PC, P, and so on, the position of the toner images that are transferred onto the recording paper 7 is shifted, resulting in color misregistration. Occur.

In order to avoid this color misregistration, as described above, a long plate-like member is attached to the conveying means, that is, the belt, which mechanically grips and conveys the leading edge of the recording paper 7 as the recording paper conveyance mechanism. Using a conveying member with a gripping element attached to a plate-like member,
A color recording apparatus (Japanese Patent Application No. 1-79097) has been proposed in which the recording paper 7 is prevented from being misaligned.

FIG. 5 is a diagram illustrating an example of a conveying member.

The conveying member is composed of a plate member 2l and a gripping element 22,
It is attached to the helmet 15 by an attachment member 20.

That is, the belt 15 has drive pulleys 17a attached to both ends of the shaft 16, as shown in belts I-15a and 15b.
and husband in 17b)? This belt is 1. 5 a
and 15b, a long plate member 2l is attached to the mounting member 2.
0 is attached to the belt 15.

Also, is there a gripping element 22 on the plate member 2l? FIG. 5 does not show the state in which the recording paper 7 is conveyed under the photosensitive column IC 1d with its leading end held by the gripping element 22.

This gripping element 22 is elastically biased to a gripping position by a spring to grip the recording paper 7, and when the plate member 21 reaches the position of the drive pulleys 17a and 17b, it is attached to the shaft 16. The projection 19 of the cam 18 is moved from the gripping position to the release position, thereby releasing the grip on the recording sleeve 7.

Then, as the drive pulleys 17a and 17b rotate in the direction of the arrow, the plate member 21 passes under the belt 15 and passes through the recording paper 7.
is carried to a position where it is to be grasped.

FIG. 6 is a diagram illustrating the gripping operation of the II feeding member.

FIG. 6(a) shows a state in which the plate-shaped member 21, which has been conveyed under the belt 15, has reached the preparation position for gripping the recording paper, and the drive booth 17 provided in the same manner as in FIG. The plate-shaped member 21, which has been transported to the position shown in FIG.

FIG. 6(b) shows a state in which the protrusion 19 is pushing up the gripping element 22, and the gripping element 22 has been displaced from the gripping position to the release position.

FIG. 6(C) shows the state immediately before the gripping element 22 comes off the tip of the protrusion 19 and shifts from the release position to the gripping position, and at this time, the leading edge of the recording paper 7 is fed out to a position where it is pinched by the gripping element 22. Indicates that the

In this way, when using the conveying member, it is possible to ensure that the leading edge of the recording paper 7 reaches the position where it is securely gripped at the same time as the recording paper 7 moves to the gripping position of the gripping element 22. is necessary.

In order to solve these problems, the present invention aims to provide a method for feeding out recording paper 7 that enables a conveying member to reliably grip recording paper 7.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the principle of the present invention.

The drive booth 17 of the image recording device moves the belt 15 to convey the conveying member 24 attached to the belt 15 to a position where it grips the recording medium 25. When the detection means 27 detects that the transport member 24 has arrived, it notifies the control means (not shown).

Upon receiving this notification, the control means controls the feeding means 26 so that the recording medium 25 reaches the gripping position when the conveyance member 24 reaches the gripping position of the recording medium 25 according to the detection output of the detection stage 27. is driven to feed out the recording medium 25 to the conveying member 24.

The conveying member 24 grips the recording medium 25 fed out by the feeding means 26 as explained in FIG. 6, and conveys the gripped recording medium 25 to the recording position of the recording stage 23.

[Effect]

By taking precautions as described above, when the gripping elements of the conveying member 24 move to the gripping position, the leading edge of the recording medium 25 has reached the gripping position, so that the conveying member 24 can reliably grip the recording medium 25. By grasping the leading end, the recording medium 25 can be generally fed once to the recording position of the 1,000 recording stages 23.

〔Example〕

FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of the configuration of the present invention.

The same reference numerals as in FIG. 4 indicate the same functions. Control circuit 3
0 is not shown in the figure. When a printing start is instructed from the secondary device, as explained in FIG.
At the same time, the recording paper 7 is fed out from the recording paper cassette 8, and is brought into contact with the standby roller 9 and placed on standby.

The conveyance member detection sensor 28 is, for example, a reflective sensor composed of a light emitting element and a light receiving element, and the belt 15 is
By moving in the direction, the plate member 2 as shown in FIG.
1 is transported, the light emitted by the light emitting element is reflected, and when the light receiving element detects this reflected light, it sends a conveyed member detection signal to the controller 41I and the same path 30.

When the control circuit 30 receives this conveyance member detection signal, it starts an internal timer, and when a predetermined time has elapsed, drives the motor 32 via the standby roller drive circuit 31 to rotate the roller 9b of the standby roller 9. let Therefore,
The roller 9a also rotates at the same time, and the recording paper 7 is fed out.

The recording paper 7 is fed out by the standby roller 9, and when the gripping element 22 attached to the plate-like member 2l reaches the optimal position for gripping the recording paper 7, the leading edge of the recording paper 7 reaches the position where it is gripped. Because it is released at the timing of reaching the position,
As shown in FIG. 6(C), when the gripping element 22 comes off the tip of the protrusion 19 of the cam 18 and moves to the gripping position, the tip of the recorder 7 is pinched and gripped.

Therefore, the plate member 21 grips the recording paper 7 as the belt l5 runs, and carries the recording paper 7 between the photosensitive drum 1a and the transfer device 5a. As explained in FIG. 4, the recording head 7 to which the yellow toner image has been transferred is moved to
The photosensitive drum 9a prevents the generation of distortion, and is carried between the next photosensitive drum lb and the transfer device 5b.

Here, the recording medium 7 to which the magenta toner image has been transferred is prevented from being distorted by a suction bell 29b, and is placed between the next photosensitive drum lc and the transfer device 5C. Here, the recording paper 7 onto which the cyan toner image has been transferred is prevented from being distorted by the suction belt 29c, and is transferred between the next photosensitive drum 1d and the transfer device 5d.

Here, as explained in FIG. 5, the recording paper 7 to which the black toner image has been transferred is conveyed to the fixing device 12 by being released from the gripping element 22, and the transferred toner image is fixed. Ru.

〔Effect of the invention〕

As explained above, the present invention makes it possible to reliably grip the recording paper when using the conveying unit to mechanically grip the recording paper and transport it once, thereby eliminating color misalignment. It is possible to transfer toner images.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a block diagram of the same circuit showing an embodiment of the present invention, Fig. 3 is a diagram explaining an example of the configuration of the present invention, and Fig. 4 is a conventional diagram. FIG. 5 is a diagram for explaining an example of the technique, FIG. 5 is a diagram for explaining an example of a conveying member, and FIG. 6 is a diagram for explaining a gripping operation of the conveying member. In the figure, la to 1d are photosensitive drums, 2a to 2d, 13 are chargers,
38~3d are exposure devices, 48~4d are developer units, 58~
5d is a transfer device, 6a to 6d are cleaners, 7 is recording paper, 8 is a recording paper cassette, 9 is a standby roller,
10, 15. 15a. 15b is a belt; 1.
1. 17. 17a and 17b are drive pulleys, 12 is a fixing device, 14 is a static eliminator, l6 is a shaft,
18 is a cam, 19 is a protrusion, 20 is a mounting member, 2l is a plate member, 22 is a gripping element, 23 is a recording means, 24 is a conveying member, 25 is a recording medium,
26 is a feeding means, 31 is a standby roller drive circuit,

Claims (1)

[Claims] A recording medium (25) is located at a position where the recording means (23) records.
a conveying member (24) that grips and conveys the recording medium (
25) to the conveyance member (24), the image recording apparatus includes a detection means (27) for detecting the position of the conveyance member (24), According to the detection output of the conveying member (27)
4) When the recording medium (25) reaches the gripping position, the feeding means (26) is driven so that the recording medium (25) reaches the gripping position, and the recording medium (25)
A method for feeding out a recording medium, comprising feeding out the medium to the conveying member (24).