JP3161112B2 - Transfer type inkjet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer. More specifically, the present invention relates to a transfer type ink jet printer that forms an ink image on a transfer medium and then transfers the ink image to a recording medium to obtain an ink image on the recording medium.

[0002]

2. Description of the Related Art In contrast to a direct type ink jet printer in which ink droplets are ejected directly onto recording paper to form an ink image, a transfer type ink jet printer is free from nozzle clogging due to unintended contact between the recording paper and a recording head. , High reliability, and paper quality (paper surface smoothness)
High image quality can be obtained without depending on the image quality. Conventional transfer type ink jet printers are disclosed in US Pat. No. 4,538,156 and US Pat.
A configuration described in Japanese Patent Application Laid-Open No. 6-206 is known. In the configuration of U.S. Pat. No. 4,538,156, an ink jet recording head having a plurality of nozzles is provided on a cylindrical transfer medium via a gap. The plurality of nozzles are arranged at predetermined intervals in a direction (rotational axis direction) orthogonal to the moving direction of the transfer medium, and the recording head is movable in this direction. In forming an ink image on the transfer medium, the recording head is moved in the direction of the rotation axis of the transfer medium while continuously rotating the transfer medium to perform ink droplet ejection and ejection, and an ink image is formed for each ring-shaped area. After forming an ink image for one page, the recording paper, which is a recording medium, is brought into contact with the transfer medium and pressed by a pressure roller, whereby the ink image is transferred to the recording paper.

In the configuration disclosed in US Pat. No. 5,099,256, a drum is used as a transfer medium, and a recording head is provided with a plurality of nozzles aligned with the moving direction of the transfer drum. Stops the transfer drum and scans the recording head in the direction of the rotation axis to form an image on one line of a predetermined width. Recording is performed while the transfer drum is intermittently rotated, and at the same time, the recording paper is printed by the transfer unit. The ink image is transferred to a recording paper by being brought into contact with a transfer drum and pressed by a pressure roller to perform recording on the recording paper.

[0004]

In the above-mentioned prior art ink-jet printer, in a first configuration, an ink image of one page is formed on a transfer medium while rotating the recording medium a plurality of times, and then the recording paper is formed. Is transferred to For this reason, during the formation of the ink image on the transfer medium, the recording paper and the pressure roller that presses the recording paper do not come into contact with the transfer medium, and the recording paper pressing unit is configured to be able to release the pressing force. It was necessary to separate the pressure roller from the transfer drum except during operation. The transfer medium has a large diameter so as to have an area of one page or more. For this reason, there has been a problem that the mechanism is complicated, the device is enlarged, and the control is complicated. Furthermore, since the recording operation is performed in two steps, a step of forming an ink image on a transfer medium and a step of transferring to a recording medium,
There was a problem that the operation was not continuous and was not suitable for high-speed recording.

In the second configuration, an ink image is formed on the transfer drum for each linear area having a predetermined width. During this time, the transfer drum is stopped. With the intermittent rotation of the transfer drum,
The transfer step is also performed intermittently. The transfer characteristics are affected by the transfer speed of the transfer medium and the recording paper in the transfer step. Therefore,
Since the transfer is performed intermittently, there is a problem that the transfer characteristics are not stable and high image quality cannot be obtained.

The present invention has been made to solve this problem, and an object thereof is to realize a transfer type ink jet printer having a simple structure.

Still another object is to realize high-speed operation by performing recording in a continuous operation. Another object is to realize high image quality with stable transfer characteristics.

[0008]

In the transfer type ink jet printer according to the present invention, an image is first written on a transfer medium which moves at a constant speed while facing the recording head by ink droplets ejected from the recording head, and then the image is printed. In a transfer type ink jet printer of a type for transferring to a recording medium, the transfer direction has a speed component substantially the same as the moving speed of the transfer medium, and a first direction not orthogonal to the moving direction of the transfer medium; Scanning means for causing the recording head to sequentially scan the transfer medium in a second direction having substantially the same speed component as the transfer medium movement speed in the medium movement direction and not orthogonal to the transfer medium movement direction. It is provided.

[0009]

An embodiment of the present invention will be described.

FIG. 1 is a perspective view of an ink jet printer according to a first embodiment of the present invention. A recording head 2 mounted on a carriage 21 scans on a transfer belt 1 as a transfer medium. Further, a heater 4 for drying the ink image, a pressure roller 3 for pressing a recording paper 8 as a recording medium, and a cleaner 5 for normalizing the surface of the transfer belt 1 are arranged around the transfer belt 1.

As shown in FIG. 3, the recording head 2 has N nozzles at intervals of p in the transfer direction of the transfer belt 1 (indicated by an arrow A in FIG. 1). Therefore, the distance between the centers of the nozzles at both ends is (N−1) × p. L = N × p is hereinafter referred to as an effective recording width.

The recording head 2 is a carriage 2 guided by guide shafts 23 and 24 via a gap with the surface of the transfer belt 1.
1 The carriage 21 scans the transfer belt 1 in the direction B perpendicular to the direction A by the carriage movement driving unit 25. The head movement driving means 6 is mounted on the carriage 21 and reciprocates the recording head 2 in the direction of arrow A. The recording head 2 is connected to wiring for supplying electric signals and power and an ink supply conduit.

The recording head movement by the head movement driving means 6 will be described. The recording head 2 is supported by support leaf springs 61 and 62 and is biased. The head movement driving means 6 is configured to wind the driving plate 63 made of a thin metal plate, and moves the recording head 2 to an arbitrary position in the direction of arrow A according to the winding amount.

The heater 6 incorporates a rod-shaped lamp 41 and irradiates the transfer belt 1 with light to dry the ink image thereon.

The guide shafts 23 and 24, the carriage movement drive means 25, the support plate springs 61 and 62, the carriage 21, the head movement means 6, and the drive plate 63 constitute a scanning means.

The cleaner 5 presses the elastic blade 51 against the transfer belt 1 to remove the remaining ink image and the like.

The transfer belt 1 is stretched by supporting rollers 11 and 12, and is moved in the direction of arrow A by a driving device (not shown). The material of the transfer belt has a small dimensional change with respect to the tension, so that the ink image can be clearly formed on the surface, the transfer to the recording paper can be performed at low pressure, and the transfer remains without any residue.The base layer reinforced with nylon wire is used here. A fluorosilicone layer is laminated on the rubber layer as an ink image carrying surface. The pressure roller 3 presses the recording paper 8 from the back surface toward the support roller 11 by a load applying device (not shown).

Next, the operation will be described. FIG. 4 shows a sequence diagram of the operation of each member shown in FIG. In FIG. 4, the horizontal axis indicates time, from the top, the moving speed of the transfer belt 1, the moving speed of the carriage 21, and the carriage 2 of the recording head 2.
1 shows the moving speed of the print head 1 and the timing at which a head drive signal for driving each nozzle of the recording head 2 is given.

At the time of the recording operation, the transfer belt 1 is rotated at a constant speed in the direction of arrow A, the carriage 21 is reciprocated in the direction of arrow B, and the recording paper 8 is conveyed in the direction of arrow C at a predetermined speed. This is performed by ejecting ink droplets from the nozzles.

The scanning operation will be further described with reference to FIG. FIG. 2 shows a scanning trajectory of the recording head on the transfer belt 1. The transfer belt 1 is moved in the direction of arrow A, and the carriage 21 reciprocates. First, in the forward path, the recording head 2 is moved at a constant speed in the direction indicated by the speed component VH1 while performing the carriage movement in the direction indicated by the speed component UH1 in FIG. As a result, the recording head 2 scans the transfer belt 1 in the first direction in which UH1 and VH1 are combined. Next, in the return path step, the recording head 2 is moved at a constant speed in the direction indicated by the speed component VH2 while performing carriage movement in the direction indicated by the speed component UH2 in FIG. As a result, the recording head 2 scans the transfer belt 1 in the second direction synthesized by UH2 and VH2.

The moving speed of the transfer belt 1 is VT, the time required for accelerating the carriage 21 is T2, the time required for moving in the direction of arrow B and the direction opposite to arrow B is T1, the time required for deceleration is T3, and When L is the dimension shown in FIG.
These are set so as to satisfy the following conditions.

L = VT × (T1 + T2 + T3) VT = VH1 = VH2 UH1 = −UH2 D = VT × (T2 + T3) As a result, the trajectory of the recording head 2 by the scanning operation in the first direction moves to the area 81. Become. Next, the carriage 21 is reversed, and the trajectory of the recording head 2 moving by the scanning operation in the second direction becomes an area indicated by 82.
A head drive signal is applied to the print head 2 in accordance with the print image in this area to selectively discharge ink droplets from each nozzle to form an ink image. Since the transfer belt 1 is moving at a constant speed at the speed VT, the above-mentioned scanning operation trajectory is
Is a region parallel to the direction of the arrow B like the recording regions 83 and 84. Therefore, the transfer belt 1 can be scanned without gaps by continuous scanning.

The ink image thus formed is dried on the transfer belt by the heater 4 to perform high-quality, high-efficiency transfer, and enters a transfer step.

The ink image on the transfer belt 1 is then transferred to a recording paper 8
And is transferred onto the recording paper 8 under pressure.

In the configuration of this embodiment, the scanning operation
On the surface of the transfer belt 1, an ink image is formed in a belt-like area (83, 84 in FIG. 2) parallel to the direction perpendicular to the moving direction of the transfer belt 1. The repetitive scanning of the recording head allows the recording to be performed so that the surface of the transfer belt 1 is filled with no gap. Therefore, since the recording area is continuous, for example, USP
As compared with the configuration of the publication No. 4,538,156, reading of recorded image data can be performed more efficiently. Scanning is performed on the transfer belt 1
The transfer belt does not intermittently move, unlike a so-called serial printer, and moves at a constant speed during operation. The characteristics of the transfer process to the recording paper 8 are affected by the transfer belt 1 during transfer and the moving speed during recording. In the configuration of the present embodiment, since the speed is constant,
Transfer can be performed with stable characteristics. Further, since recording is performed in the reciprocating process of the recording head 2, recording is performed at high speed.

FIG. 5 shows a second embodiment. The overall configuration is the same as that of the first embodiment, and the description is omitted. A guide plate 50 is provided above the carriage 21 and the guide shafts 23 and 24. The guide plate 50 has a guide groove 51 formed therein.
The scanning operation of the recording head 2 is performed in the first direction (the direction indicated by the arrow G) and the second direction (the direction indicated by the arrow H) with the movement of the carriage 21 by the slider 52 guided here.

Guide plate 50, carriage 21, slider 5
2. The guide shafts 23 and 24 constitute scanning means.

As in the case of the first embodiment, recording is performed such that the surface of the transfer belt 1 is filled with no gap by repetitive scanning of the recording head 2.

FIG. 6 shows a third embodiment. FIG. 7 is a sequence diagram showing the operation of each element during operation. A transfer drum 13 is used as a transfer medium. The transfer drum 13 is driven to rotate by a rotation unit 15. A swingable head moving plate 72 is intermittently driven by a clutch 74, and a control plate 75 connected to the head moving plate 72 is supported by a support spring 64 when the clutch 74 is on. To move the transfer drum 13 in the circumferential direction at the same speed as the outer circumferential movement speed of the transfer drum 13. When the clutch 74 is off, the return spring 73 returns to the position of the pin 71.

In the sequence diagram of FIG. 7, time is shown on the horizontal axis, the rotation speed of the transfer drum 13 and the carriage 21 from the top.
, The rotational speed of the head moving plate 72 for moving the recording head 2 in the moving direction of the transfer drum 13, and the clutch 7
4 shows the timing at which a drive signal of No. 4 and a head drive signal for driving each nozzle of the recording head 2 are given.

During the recording operation, the transfer drum 13 is rotated at a constant speed in the direction of arrow A, the carriage 21 is reciprocated in the direction of arrow B, and the recording paper 8 is transported in the direction of arrow C at a predetermined speed. This is performed by ejecting ink droplets from the nozzles.

The carriage 21, the carriage moving drive unit 25, the guide shafts 23 and 24, the head moving plate 72, the clutch 74, the control plate 75, the support spring 64, the return spring 73, and the pin 71 constitute a scanning unit.

In this configuration, no cleaner and no heater are provided. Other configurations are the same as those of the first embodiment, and the description is omitted.

As in the previous embodiment, the surface of the transfer belt 1 is painted without gaps by repeated scanning of the recording head.

[0035]

According to the ink jet printer of the present invention, after forming an ink image for one page on a transfer medium,
Instead of transferring the image to the recording medium, an ink image is formed for each band-shaped area perpendicular to the moving direction of the transfer medium while continuously moving the transfer medium. The recording is performed by reciprocating scanning with a recording head while moving the transfer medium continuously at a constant speed and in a direction perpendicular to the moving direction of the transfer medium. Therefore, two steps of an ink image forming step of forming an ink image on the transfer medium at a predetermined portion of the transfer medium and a transfer step of transferring to a recording medium at another place can be performed simultaneously. Therefore, there is no need to release the contact between the recording medium and the transfer medium at the portion where the image is transferred to the recording medium, and the transfer type inkjet printer having a simple configuration can be realized.

Further, since the above two steps proceed continuously and simultaneously, recording is performed in a continuous operation, and further, since the recording head can perform reciprocal scanning, high speed operation can be realized.

In a scanning method generally used in a serial printer, the transfer medium is stopped during one scanning process, and the transfer medium is fed by a predetermined length until the next scanning operation. A subsequent scanning step is performed. this,
When applied to a transfer type ink jet printer, the transfer medium needs to perform an intermittent feeding operation. At this time, the contact time between the transfer medium and the recording medium at the transfer portion is not constant. During the time when the transfer medium is stopped, the transfer medium and a specific portion of the recording medium continue to be in contact with each other. Therefore, the transferred image is not stable. In the configuration of the present invention, as apparent from the above description, the transfer medium moves at a constant speed during the reciprocating operation time of the recording head. Therefore, the transfer medium is continuously conveyed, so that there is no need for intermittent drive control, the mechanism and the control can be simplified, and a transfer ink image of stable quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a transfer type ink jet printer according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a scanning operation of the transfer type ink jet printer of the present invention.

FIG. 3 is a diagram illustrating a nozzle arrangement of a recording head used in the transfer type ink jet printer of the present invention.

FIG. 4 is a diagram showing an operation sequence at the time of a recording operation of members constituting the transfer type ink jet printer according to the first embodiment of the present invention.

FIG. 5 is a perspective view of a transfer type ink jet printer according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a transfer type ink jet printer according to a third embodiment of the present invention.

FIG. 7 is a diagram showing an operation sequence at the time of a recording operation of members constituting a transfer type ink jet printer according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transfer belt (transfer medium) 2 Recording head 3 Pressure roller 4 Heater 5 Cleaner 6 Head moving means 8 Recording paper (Recording medium) 11, 12 Support roller 13 Transfer drum (Transfer medium) 21 Carriage 23, 24 Guide shaft 25 Carriage Moving drive means 50 Guide plate 51 Guide groove 52 Slider 61, 62 Support plate spring 63 Drive plate 71 Pin 72 Head moving plate 73 Return spring 74 Clutch 75 Control plate

Claims (1)

(57) [Claims] 1. A transfer type ink jet printer of a type in which an image is first written on a transfer medium which moves at a constant speed while confronting a print head with ink droplets ejected from the print head, and then the image is transferred to the print medium. A first component that has substantially the same speed component as the moving speed of the transfer medium with respect to the moving direction of the transfer medium and is not orthogonal to the moving direction of the transfer medium; Scanning means for causing the recording head to sequentially scan the transfer medium in a second direction which has a speed component substantially equal to the movement speed of the medium and is not orthogonal to the movement direction of the transfer medium. Characteristic transfer type inkjet printer.