JP2002182515A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recorder which can well transport a continuous body to be recorded such as a plastics film with a shape of paper or sheet. SOLUTION: The image recorder which records a two-color image on both sides of a continuous body to be recorded 1 has transport rollers 71 and 72 which transport the body to be recorded 1, discharge rollers 73 and 74, a regulating means 8 which controls the position of the body to be recorded 1 in a width direction, a tension control part 2 which applies tension to the body to be recorded 1, a toner carrier, image recording means 3a, 3b, 3c, and 3d which transfer a toner image formed on a toner carrier surface to the body to be recorded 1, and a fixing means 5 which fixes the toner image transferred on the body to be recorded 1. In such an image recorder, the transportation torque of the discharge rollers 73 and 74 which apply tension to the body to be recorded 1 provided at the downstream side of the fixing means 5 is set larger than the transportation torque of heating rollers 53 and 54 of the fixing means 5 to transport the body to be recorded 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus provided with a conveying means for conveying a recording medium such as a sheet of paper or a plastic film.

[0002]

2. Description of the Related Art In an image recording apparatus, a method of fixing an unfixed toner image on a recording medium is performed by pressing an unfixed toner image on the recording medium with a heat roller having heating means therein. And a method of fixing the recording medium by passing it between two plate heaters.

[0003] Among these methods, in the method of passing between plate heaters, it is necessary to lengthen the plate heater in order to secure a heating time suitable for fixing an unfixed toner image. The longer the plate heater, the larger the image recording device.

[0004] On the other hand, in the method in which pressure is applied by a heat roller, the heated portion of the fixing device requires only the diameter of the heat roller.
The size of the image recording apparatus can be suppressed, and in recent years, heat rollers have become the mainstream.

[0005] As described above, the unfixed toner image formed on the recording medium in the image recording unit is fixed by a fixing machine having a heat roller, and the paper is controlled by controlling a conveying means provided downstream of the fixing unit. For example, Japanese Patent Application Laid-Open No. 9-86754 and Japanese Patent Application Laid-Open No. 8-268614
And the like.

[0006] Japanese Patent Application Laid-Open No. 9-86754 discloses that a conveying means provided on the downstream side of a fixing device provided in an image recording apparatus can change the conveying speed of a sheet between the start and the start of an image forming operation. This prevents wrinkles from being generated on the conveyed and discharged paper.

[0007] Also, Japanese Patent Application Laid-Open No. 8-268614 discloses that
When the recording medium is simultaneously held between the heat roller of the fixing device provided in the image recording apparatus and the discharge roller of the discharge unit downstream thereof, the recording medium is conveyed at the conveyance speed of the fixing device, and the recording is performed. If the paper is conveyed while the rear end of the body passes through the fixing device and is pinched only by the discharge rollers of the discharge unit, the paper is conveyed at the conveyance speed of the rollers of the discharge unit to shorten the paper conveyance time of the discharge unit. are doing.

[0008]

An image recording apparatus having a heat roller is required to have a higher image recording speed year by year, and the rotation of the heat roller and a discharge roller for discharging the recording medium is increasing. . In the case where the speed of the carry-out roller is increased, if the rotation timing of the carry-out roller and the rotation timing of the heat roller are not well-balanced, the recording medium may be wrinkled or torn.

On the other hand, the transfer speed of the recording medium in JP-A-9-86754 and JP-A-8-268614 is determined by the rotation speed of the heat roller and the transfer roller. Is changed due to thermal expansion, the rotation timing of the heat roller and the transport roller becomes unbalanced, the tension of the recording medium becomes weak, and the upper image is disturbed and the image quality is deteriorated.

As described above, the heat roller has a problem peculiar to the image recording apparatus using the heat roller that the rotation cannot be kept constant as long as thermal expansion occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image recording apparatus in which image distortion and image quality deterioration are reduced.

[0012]

The object of the present invention is to provide a conveying means for conveying a continuous recording medium, an image recording means for transferring a toner image formed on a toner carrier surface to the recording medium, and an image recording apparatus. An image recording apparatus comprising: a fixing unit of a heat roller for fixing the toner image transferred to a recording medium; and a discharge roller for discharging the recording medium to the outside of the apparatus, wherein the transfer torque of the discharge roller is controlled by the heat roller. Is achieved by making the transfer torque larger than the transfer torque.

[0013] Further, it is achieved that the discharge roller regulates the conveying speed of the recording medium.

[0014] Further, this is achieved by providing a rotation regulating means for applying a constant torque to the heat roller.

[0015] Further, it is achieved that the heat roller is driven and rotated by the conveyance of the recording medium.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image recording apparatus provided with the present invention. FIG. 2 is a diagram illustrating a transport torque relationship between a discharge roller and a heat roller of an image recording apparatus provided with the present invention. FIG. 3 is a perspective view showing an embodiment of a mechanism for applying a constant torque to the heat roller.

Referring to FIG. 1, the overall configuration of the image recording apparatus will be described. FIG. 1 shows a two-color laser printer for double-sided printing. 1 is a recording medium wound in a roll shape,
It is a continuous plastic film or the like in paper or sheet form. The recording medium 1 includes auxiliary rollers 61, 62, 6
3, 64, and the transport roller 7 via the paper feed rollers 12, 13.
1, 72. The transport rollers 71 and 72 serve as transport means for sending the recording medium 1 to the image recording means side. Reference numeral 2 denotes a tension control unit for applying a tension to the recording medium 1 fed from the transport rollers 71 and 72 via an auxiliary roller 65. A weight “W” is attached to the tension control unit 2, and a load is applied to the recording medium 1 via the dancer roller 20. This dancer roller 20
Applies a pulling force to the recording medium 1 between the conveying rollers 73 and 74 from the conveying rollers 71 and 72, and controls the rotation of the conveying rollers 71 and 72 according to the expansion and contraction of the recording medium 1. Has become.

Reference numeral 8 denotes an auxiliary roller 66, 67 for regulating the position of the auxiliary roller 66, 67 and the recording medium 1 in the width direction.
Two position regulating rollers 8 provided in parallel to 67
This is a position restricting means composed of the position detection sensors 1 and 82 and the position detection sensor 83. The recording medium 1 that has passed through the position regulating means 8 is
After passing through the auxiliary roller 68, it is sent to the toner image recording unit 3a.

Recording units 3a, 3b for forming toner images
3c and 3d are arranged so as to form an image of two colors per side. The toner image recording units 3a, 3b, 3
c and 3d are the toner carriers. The toner image recording units 3a, 3b, 3c and 3d rotatably provide a photosensitive drum 31 having a photosensitive layer coated on a metal drum surface, and uniformly charge the outer peripheral surface of the photosensitive drum 31. A charger 32 is provided. Further, on the photosensitive drum 31, an optical system 33 for forming an electrostatic latent image and a developing unit 34 for visualizing the electrostatic latent image with toner to form a toner image are provided. Further, a transfer corotron 35 for transferring the toner image on the photosensitive drum 31 to the recording medium 1.
And a drum cleaner 36 for removing residual toner after transfer.
Is provided. The transfer corotron 35 serves as an image recording unit on the recording medium 1.

In FIG. 1, reference numerals for the charger 32, the optical system 33, the developing unit 34, the transfer corotron 35, and the drum cleaner 36 are assigned only to the toner image recording section 3a, but the toner image recording section 3b. , 3c, and 3d have the same configuration, and a description thereof will be omitted.

The recording medium 1 includes toner image recording sections 3a and 3a.
b, a transfer image of two colors is formed on the first surface (front surface), the transport direction is reversed by the guide rollers 41 and 42, and the second surface (back surface) is formed by the toner image recording units 3c and 3d.
To form a transfer image of two colors. Reference numerals 51 and 52 denote double-sided preheaters that are not in contact with the recording medium 1. 53, 5
Reference numeral 4 denotes a heat roller, which is a means for fixing an image to the recording medium 1, and is provided on both surfaces of the recording medium 1. By pressing the heat rollers 53 and 54 from both sides of the recording medium 1, the two-color unfixed toner images on both sides of the recording medium 1 are fixed, and a permanent image is formed on the recording medium 1.

The recording medium 1 on which the permanent image is formed is conveyed by a discharge roller 73, 74 to a post-processing device (not shown). The discharge rollers 73 and 74 are transport means for discharging the recording medium 1 out of the apparatus. Reference numeral 5 denotes a fixing device including these double-sided plate heaters 51 and 52 and heat rollers 53 and 54.

Next, the operation of the image recording apparatus provided with the present invention will be described with reference to FIGS.

The continuous recording medium 1 wound in a roll shape is
While applying the back tension at a speed slightly lower than the rotation speed of the transport rollers 71 and 72,
3, the paper is fed to the transport rollers 71 and 72. The conveying rollers 71 and 72 adjust the speed so that the tension fluctuation due to the paper feeding operation of the recording medium 1 is not transmitted to the downstream side, and play a role of interrupting the tension fluctuation.

The recording medium 1 transported to the transport rollers 71 and 72 is transported by transport rollers 71 and 72 and discharge rollers 73 and 74.
, Ie, the toner image recording units 3a, 3b, 3
The tension is controlled by the tension controller 2 to keep the predetermined tension constant on c and 3d. The tension controller 2 detects a displacement when the dancer roller 20 moves in the vertical direction by a detection device (not shown), and adjusts the rotation speed of the transport rollers 71 and 72 via a control device (not shown). Thus, the fluctuation of the tension of the recording medium 1 is suppressed.

The recording medium 1 whose tension is controlled is sent to the fixing device 5 after toner images are formed on both sides thereof by the toner image recording sections 3a, 3b, 3c and 3d. In the fixing device 5, the unfixed toner image formed on the recording medium 1 is preheated by the double-sided pre-heaters 51 and 52,
At 54, the recording medium is pressed and heated to be fixed to the recording medium 1. The double-sided preheaters 51 and 52 heat the unfixed toner image in advance before the unfixed toner passes through the double-sided heat rollers 53 and 54, and supplement the heating of the double-sided heat rollers 53 and 54. Thereby, the fixing time is shortened.
The recording medium 1 on which the toner image has been fixed is discharged from the discharge roller 73,
By 74, it is conveyed to a post-processing machine (not shown).

The heat rollers 53 and 54 are made of hard rubber, and the heat from the internal heater causes the hard rubber to thermally expand and change the roller diameter. Can not be kept. Accordingly, in the present embodiment, as shown in FIG.
3 and 74 are transferred to the heat rollers 53 and 54.
(T2> T1). As a result, the discharge rollers 73 and 74 always pull the recorded 1 and, for example, the heat roller 5
Even if the transport speed of the recording medium 3 or 54 changes, wrinkles or tears J on the recording medium 1 can be prevented.

As shown in FIG. 3, a gear 55 and a torque limiter 56 provided at the end of the lower heat roller 54 are provided.
The recording medium 1 is conveyed by being driven to rotate while applying a constant torque to the heat rollers 53 and 54. This makes it possible to apply tension to the recording medium 1 while keeping the conveyance speed of the recording medium 1 constant, so that the recording medium 1 can be accurately conveyed.

For example, in this embodiment, the discharge rollers 73,
The transfer torque T2 of the heat rollers 53 and 54 is determined in consideration of the thermal expansion of the heat rollers 53 and 54.
1 was set to 1.2 to 1.5 times. Also, the transport roller 7
If the transport speed between the rollers 1 and 72 and the discharge rollers 73 and 74 is defined by the discharge rollers 73 and 74, the transport speed of the recording medium 1 can be controlled with high accuracy.

In this embodiment, a laser printer having a two-sided two-color toner image recording unit has been described. However, a laser printer having a two-sided four-color toner image recording unit is similarly applicable.

FIG. 4 is a perspective view showing another embodiment of a mechanism for applying a constant torque to the heat rollers 53 and 54. In FIG. 4, a friction brake pad 57 is pressed against the end of the lower heat roller 54 by a spring 58. When the recording medium 1 is moved by being pulled by the discharge rollers 73 and 74, a certain load is applied to the heat rollers 53 and 54 that are driven by the movement.
As a result, the heat rollers 53 and 54 rotate with a constant transport torque.

FIG. 5 is a schematic configuration diagram of a single-sided printing two-color laser printer. In FIG. 5, the embodiment of FIG. 1 has a configuration for forming a two-sided two-color image, whereas the present embodiment has a configuration for forming a single-sided two-color image.

A continuous recording medium 1 such as a roll of paper or a sheet-like plastic film is formed by auxiliary rollers 61, 62, 63, 64, paper feed rollers 12, 13.
Are sent to the conveying rollers 71 and 72 via the. The recording medium 1 fed from the transport rollers 71 and 72 is provided with a tension controller 2 for applying tension to the recording medium 1 via the auxiliary roller 65, auxiliary rollers 66 and 67, and a position of the recording medium 1 in the width direction. After passing through a regulating means 8 composed of two parallel position regulating rollers 81 and 82 and a position detection sensor 83, and an auxiliary roller 68, the toner is sent to the toner image recording section 3a. The recording medium 1 includes a toner image recording unit 3
a, 3b, a two-color transfer image is formed on one side, and then passes through the fixing device 5 that generates heat from the preheater 52 and the heat roller 54 on the lower surface to form a permanent image on the recording medium 1. . The recording medium 1 on which the permanent image has been formed is placed on a discharge roller 7
It is conveyed to a post-processing device (not shown) by 3, 74.

FIG. 6 is a schematic configuration diagram of a two-color laser printer for duplex printing using folding paper.

In FIG. 6, the embodiment of FIG. 1 uses a continuous recording medium 1 such as a roll of paper or a sheet of plastic film, whereas the present embodiment differs from the embodiment of FIG. And a box paper 14 folded at a perforation and contained in a cardboard box or the like.

5 and 6, similarly to the embodiment of FIG. 1, the transport torque T
2 is set to be larger than the transfer torque T1 of the heat rollers 53 and 54, and the recording medium 1 is conveyed.
The recording medium 1 can be conveyed with high accuracy because the tension can be applied while keeping the conveyance speed of the recording medium 1 constant. Further, since the transport speed between the transport rollers 71, 72 and the discharge rollers 73, 74 is defined by the discharge rollers 73, 74, the transport speed of the recording medium 1 can be controlled with high precision.

According to the present invention, since the continuous conveying speed and tension of the recording medium can be kept constant, color shift at each image recording section when transferring the toner image to the recording medium can be prevented, and high printing can be achieved. A quality recorded image can be obtained.

[0038]

As described above, according to the present invention,
Since the conveyance speed and tension of the continuous recording medium can be kept constant, color shift in each image recording unit when transferring the toner image to the recording medium can be prevented, and a recording image of high print quality can be obtained. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a two-sided printing two-color laser printer which is a first embodiment of an image recording apparatus provided with the present invention.

FIG. 2 is a diagram illustrating the relationship between the conveyance torque of a discharge roller and a heat roller of an image recording apparatus provided with the present invention.

FIG. 3 is a perspective view showing an embodiment of a mechanism for applying a constant torque to a heat roller.

FIG. 4 is a perspective view showing another embodiment of a mechanism for applying a constant torque to a heat roller.

FIG. 5 is a schematic configuration diagram of a single-sided printing two-color laser printer.

FIG. 6 is a schematic configuration diagram of a two-sided printing two-color laser printer using folding paper.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording object, 2 ... Tension control part, 3 ... Image recording part, 5 ...
Double-sided fixing machine, 53, 54 ... Heat roller, 61-68 ...
Auxiliary rollers, 71, 72: conveyance rollers, 73, 74: discharge rollers, 8: recording medium position regulating means.

Continued on the front page (72) Inventor Kazuyasu Sato 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. In-house (72) Inventor Akitomo Kuwahara 1060 Takeda, Hitachinaka-shi, Ibaraki Pref. Inside Hitachi Koki Co., Ltd. (72) Inventor Tetsuya Oba 1060 Takeda, Hitachinaka-shi, Ibaraki Pref. ED19 ED25 EE03 EE04 EF09 2H033 AA14 AA15 BA10 BB37 CA09 CA36 CA39 CA40 3F105 AA02 AA04 AB01 AB02 AB04 BA01 BA07 DA12

Claims (4)

[Claims] A conveying means for conveying a continuous recording medium;
Image recording means for transferring the toner image formed on the surface of the toner carrier to the recording medium; fixing means for a heat roller for fixing the toner image transferred to the recording medium; An image recording apparatus comprising: a discharge roller for discharging outside; wherein the transport torque of the discharge roller is greater than the transport torque of the heat roller. 2. An image recording apparatus according to claim 1, wherein said discharge roller regulates a conveying speed of said recording medium. 3. An image recording apparatus according to claim 1, further comprising a rotation regulating means for applying a constant torque to said heat roller. 4. An image recording apparatus according to claim 1, wherein said heat roller is driven to rotate by conveyance of said recording medium.