JP2002331717A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder in which contact between a recording medium and a recording head is prevented even if the recording medium is stretched due to ink ejected from a recording head and high definition image can be recorded by enhancing the accuracy of carriage. SOLUTION: The ink jet recorder comprises a roller for carrying a recording medium on the upstream side of a recording head in the carrying direction of the recording medium, and a sheet discharge roller for carrying the recording medium on the downstream side of the recording head in the carrying direction of the recording medium wherein the speed of the sheet discharge roller can be controlled variably with respect to the speed of the carrying roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for ejecting ink onto a recording medium to perform recording, and more particularly, to an ink jet recording apparatus used in an information processing apparatus such as a printer, a copying machine, a computer, or a word processor. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, in a recording apparatus such as a printer, a copying machine, and a facsimile, as a mechanism for transporting a recording sheet as a recording medium, a transport roller or a recording sheet is pressed against the transport roller to clamp the transport force. There is provided a mechanism including a pinch roller to be generated, a means for generating an urging force for the pressing of the pinch roller, and the like. This transport mechanism transports a recording sheet fed from a paper feed unit in a recording area by a recording head, and is generally provided in two pairs before and after this recording area. Accordingly, the recording sheet can be transported in the recording area with high accuracy, and a predetermined tension can be applied to the recording sheet during this period to keep a wide area flat.

FIG. 9 is a cross-sectional view mainly showing a recording sheet transport mechanism in a conventional example of an ink jet type recording apparatus.

In FIG. 9, a recording head 7 mounted on a carriage unit 50 scans in a direction perpendicular to the plane of the drawing and discharges ink during this scanning to perform recording. The recording sheet P is conveyed substantially horizontally from the right side to the left side in FIG. That is, with respect to the recording area, a pair of the transport roller 36 and the pinch roller 37 and a pair of the discharge roller 41 and the spur 42 are provided on the upstream side and the downstream side of the recording sheet transport, respectively, by the two pairs of transport mechanisms described above. It is provided as. Among these, the pinch roller 37 is rotatably supported by a rotation shaft provided on the pinch roller holder 30, and the pinch roller holder 30 is urged by the pinch roller spring 31,
The pinch roller 37 can be pressed against the transport roller 36. A pressing force (not shown) also acts between the discharge roller 41 and the spur 42 in the same manner. Then, the recording sheet P is nipped by these two pairs of rollers, and the conveyance roller 36 and the discharge roller 41 are rotated by a driving mechanism (not shown), so that the recording sheet P It is transported by a predetermined amount for each scan.

In the above-described ink jet recording apparatus, the driving source of the transport roller and the discharge roller is common, and the speed of the discharge roller is set to be higher than the speed of the transport roller. As a result, a constant tension is applied to the recording medium, and recording is performed by the recording head in a state where there is little slack.

[0006]

However, the conventional ink jet recording apparatus has the following problems. If the amount of ink ejected from the recording head onto the recording medium is large, the recording medium extends in the transport direction of the recording medium, and the amount of extension cannot be absorbed by increasing the speed of the discharge roller relative to the transport roller. There is a possibility that the recording medium may be stained by the contact of the head. In particular, when the recording medium was plain paper, the amount of elongation of the recording medium was remarkable.
Further, among plain papers, in the case of plain paper having a horizontal direction such as A3 plain paper vertical feed, A4 plain paper horizontal feed, A5 plain paper horizontal feed, etc., the amount of elongation of the recording medium is particularly remarkable. And the recording head may come into contact with each other.

Further, in order to absorb the expansion of the recording medium by the ink discharged from the recording head, if the rate of increase of the discharge roller with respect to the transport roller is set in accordance with the recording medium having the largest amount of expansion, the ink is discharged. The recording medium is strongly pulled by photographic paper or the like which does not stretch much even when the recording medium is stretched, and there is a problem that the conveyance accuracy of the recording medium is deteriorated and the image is deteriorated.

[0008] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide an ink jet recording apparatus capable of preventing a recording medium from coming into contact with a recording head even when the recording medium is stretched by ink ejected from the recording head and capable of recording a high-definition image with good transport accuracy. I do.

[0009]

To achieve the above object, one aspect of the ink jet recording apparatus according to the present invention is:
In an inkjet recording apparatus that performs recording by discharging ink from a recording head to a recording medium according to image data,
A transport roller that transports the recording medium upstream of the recording head with respect to the transport direction of the recording medium, and a paper discharge roller that transports the recording medium downstream of the recording head with respect to the transport direction of the recording medium. The speed of the discharge roller with respect to the speed of the transport roller can be variably controlled.

According to the above construction, even if the recording medium is stretched by the ink ejected from the recording head, it is possible to prevent the recording medium from coming into contact with the recording head and to record a high-definition image with good transport accuracy. An inkjet recording head can be provided.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<First Embodiment> An ink jet recording apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a sectional view of an ink jet recording apparatus 100 according to the first embodiment.

The ASF base 18 stores a recording medium S loaded on a pressure plate 19. The paper feed roller 20 is disposed so as to send out the recording medium S pressed by the pressure plate 19. On the downstream side of the ASF base 18, a recording medium S
Sensor lever 1 and PE for detecting the presence or absence and the end
A sensor 2 is provided. A transport roller 4 and a pinch roller 5 pressed against the transport roller 4 by a spring (not shown) are disposed downstream of the PE sensor lever 1. The conveyance roller 4 is configured to cooperate with the pinch roller 5 to convey the recording medium S in the conveyance direction (the direction of arrow A in the figure). The transport roller 4 is rotated by a transport motor (not shown) and transports the recording medium S by a predetermined amount.

The recording section (image forming means) 6 includes a carriage 8, a guide shaft 9 for guiding the carriage 8 reciprocally in a direction intersecting the transport direction A of the recording medium S,
A recording head 7 and the like mounted on a carriage 8 are provided. The recording head 7 forms an image by discharging ink onto the recording medium S transported onto the platen 10 by the transport roller 4 and the pinch roller 5.

At the downstream side of the recording head 7, a paper discharge roller 1 is provided.
A transport rotating body pair 21 composed of 1 and a spur 12 is provided. The transport rotator pair 21 rotates while holding the recording medium S on which an image is formed, and discharges the recording medium S onto a discharge tray (not shown) without soiling the recording surface Sa of the recording medium S. Has become. The discharge roller 11 is rotated by a discharge motor (not shown). Transporting the recording medium S to the transport roller 4
When the paper is conveyed by the paper discharge roller 11 and the paper discharge roller 11, (speed of the paper discharge roller) = (speed of the conveyance roller) × (speed increase rate). Since the transport motor and the paper discharge motor are independent of each other, the rate of increase of the speed of the paper discharge roller with respect to the speed of the transport roller can be made variable.

FIG. 2 is a block diagram of the ink jet recording apparatus according to the first embodiment. In FIG.
Is an MPU for controlling the entire recording apparatus, and includes a timer 105 for managing time in control. 106 is M
ROM 107 containing a control program of PU 104, 107
A RAM stores a work area when the control of the MPU 104 is executed and a drive table of the motor. Reference numeral 108 denotes an EEPROM capable of retaining information even when the power of the recording apparatus is turned off.
M. A carriage motor driver 109 controls a carriage motor 111 for driving the carriage 8. A transport motor driver 112 controls the transport motor 113 that drives the transport roller 4. A recovery system motor driver 114 controls a recovery system motor 115 that drives a recovery system that performs a recovery operation of the recording head 7. A paper discharge motor driver 116 controls a paper discharge motor 117 that drives the paper discharge roller 11.

Reference numeral 103 denotes an interface unit for connecting the recording device to a host computer or the like. The recording device is
Information can be exchanged with a host computer or the like via the interface unit 103. Reference numeral 101 denotes an electronic device such as a computer or a word processor, which is connected to a recording device via an interface unit 103. Reference numeral 102 denotes a printer driver for performing various settings related to the printing apparatus.
The recording device is instructed according to the setting.

FIG. 3 is a flowchart of the ink jet recording apparatus according to the first embodiment. First, step S
At 11, image data to be recorded is received from an electronic device such as a host computer. Next, step S12
Calculates the amount of ink applied to the recording medium from the received image data.

In step S13, the speed increase rate of the paper discharge roller 11 with respect to the transport roller 4 is determined from the calculated ink application amount. For example, when the ink application amount is the first amount, the speed of the discharge roller 11 with respect to the speed of the transport roller 4 is set at a first rate of increase, and the second amount is larger than the first amount. In this case, the speed of the paper discharge roller 11 with respect to the speed of the transport roller 4 is set at a second speed increase rate larger than the first speed increase rate. That is, as the amount of applied ink increases, the rate of increase in the speed of the paper discharge roller 11 with respect to the speed of the transport roller 4 is increased.

Then, in step S14, S13
The transport motor 113 and the discharge motor 117 rotate the transport roller 4 and the discharge roller 11 at the speed increase rate determined
To perform a recording operation. In step S15,
When the recording operation is completed, the recording medium is discharged to a discharge tray (not shown).

Incidentally, as shown in FIG.
The relationship between the speed increase rate X of the discharge roller with respect to the transport roller may be stored in a table in advance, and control may be performed so that the speed increase rate is determined from the table.

According to the configuration described above, the rate of increase of the speed of the discharge roller with respect to the speed of the transport roller can be variably controlled in accordance with the image data to be recorded on the recording medium. It is possible to provide an ink jet recording apparatus which can prevent the contact between the recording head and the recording head, and can record a high-definition image with good transport accuracy.

<Second Embodiment> An ink jet recording apparatus according to a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment only in the control of the printing apparatus.

The amount of expansion (expansion) of the recording medium when ink is applied to the recording medium differs depending on the type of recording medium (plain paper, glossy paper, glossy film, photographic paper, etc.)
In particular, the amount of expansion of plain paper is extremely large as compared with other recording media. Therefore, in the present embodiment, the rate of increase in the speed of the discharge roller with respect to the speed of the transport roller is changed according to the type of recording medium.

FIG. 5 is a flow chart of the ink jet recording apparatus according to the second embodiment. First, step S
At 21, image data to be recorded is received from an electronic device such as a host computer. Next, step S22
Calculates the amount of ink applied to the recording medium from the received image data.

Next, in step S23, the type of the recording medium is determined. The type of the recording medium may be determined by obtaining information set when the image data is transmitted by the host computer or the like, or may be determined by the recording apparatus based on the type of the image data.

In step S24, the speed increase rate of the discharge roller 11 with respect to the transport roller 4 is determined from the calculated amount of applied ink and the type of recording medium. At this time, as in the first embodiment, the speed increase rate X determined from the ink application amount X
And the speed increase rate Y determined from the type of the recording medium shown in FIG.
And a value obtained by multiplying the speed by the speed of the discharge roller with respect to the speed of the transport roller. Then, step S2
In step 5, the transport motor 11 rotates the transport roller 4 and the discharge roller 11 at the speed increase rate determined in S24.
3. The paper discharge motor 117 is driven to perform a recording operation. In step S26, when the recording operation is completed, the recording medium is discharged to a discharge tray (not shown).

Further, the plain paper extends in different directions between the horizontal and vertical eyes, and when recording on plain paper with horizontal eyes, the amount of elongation in the transport direction of the recording medium is large. Therefore, as shown in FIG. 7, a table for determining the rate of increase of the speed of the discharge roller with respect to the speed of the transport roller according to the size of the recording medium, the transport direction of the recording medium, and the type of the recording medium is used. May be. Accordingly, it is possible to provide an ink jet recording apparatus capable of reliably preventing the recording medium and the recording head from contacting the plain paper in the horizontal direction, and capable of recording a high-definition image with good transport accuracy.

Further, as shown in FIG. 8, a table for determining the rate of increase of the discharge roller with respect to the transport roller in addition to the parameter of the ink application amount may be used.

According to the configuration described above, the rate of increase of the speed of the discharge roller with respect to the speed of the transport roller can be variably controlled in accordance with the type of the image data and the recording medium to be recorded on the recording medium. It is possible to provide an ink jet recording apparatus which can prevent the recording medium from coming into contact with the recording head due to expansion and can record a high-definition image with good transport accuracy.

In each of the embodiments described above, a serial type printing apparatus that moves a print head in the main scanning direction is provided.
It has a configuration to which the present invention is applied. However, the present invention is directed to a full-line type recording apparatus that uses a recording head that extends over the entire area in the width direction of the recording sheet and continuously conveys the recording sheet while recording an image by the recording head. Can also be applied.

In each of the above-described embodiments, an example using a so-called BJ type recording head among the ink jet types has been described. However, the present invention can be applied to various recording methods irrespective of the recording method of the recording head. As a recording method of the recording head, for example, in addition to the BJ method, a piezo method may be used, and a recording head of a method including various recording elements, such as a thermal transfer method, may be used instead of an ink jet method.

[0034]

As described above, according to the present invention,
Since the speed of the paper discharge roller with respect to the speed of the conveyance roller can be variably controlled, even if the recording medium is stretched by the ink ejected from the recording head, the recording medium and the recording head are prevented from coming into contact with each other, and the conveyance accuracy is improved. An ink jet recording apparatus capable of recording a good and high-definition image can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an ink jet recording apparatus according to a first embodiment.

FIG. 2 is a block diagram of the inkjet recording apparatus according to the first embodiment.

FIG. 3 is a flowchart of the inkjet recording apparatus according to the first embodiment.

FIG. 4 is a table showing a relationship between an ink application amount and a speed increase rate of a discharge roller with respect to a transport roller.

FIG. 5 is a flowchart of the inkjet recording apparatus according to the second embodiment.

FIG. 6 is a table illustrating a relationship between a type of a recording medium and a speed increase rate of a discharge roller with respect to a conveyance roller.

FIG. 7 is a table for determining a speed increase rate of a discharge roller with respect to a conveyance roller according to a size of the recording medium, a conveyance direction of the recording medium, and a type of the recording medium.

FIG. 8 is a table for determining a speed-up rate of a paper discharge roller with respect to a transport roller by adding an ink application amount parameter to the table of FIG. 7;

FIG. 9 is a cross-sectional view mainly showing a recording sheet conveying mechanism of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PE sensor lever 2 PE sensor 4 Conveyance roller 5 Pinch roller 6 Recording part 7 Recording head 8 Carriage 9 Guide shaft 10 Platen 11 Discharge roller 12 Spur

Claims (8)

[Claims] 1. An ink jet recording apparatus which performs recording by discharging ink from a recording head to a recording medium according to image data, comprising: a transport roller for transporting the recording medium upstream of the recording head with respect to a transport direction of the recording medium. And a discharge roller that conveys the recording medium downstream of the recording head with respect to the recording medium conveyance direction, wherein the speed of the discharge roller with respect to the speed of the conveyance roller can be variably controlled. An ink jet recording apparatus comprising: 2. The ink jet recording apparatus according to claim 1, wherein a drive source of the transport roller and a drive source of the discharge roller are independent. 3. The ink jet recording apparatus according to claim 1, wherein a speed of the discharge roller with respect to a speed of the transport roller is controlled according to the image data. 4. The ink jet recording apparatus according to claim 3, wherein the speed of the paper discharge roller with respect to the speed of the transport roller is controlled in accordance with the amount of ink applied to the recording medium. 5. The ink jet recording apparatus according to claim 4, wherein the speed of the discharge roller relative to the speed of the transport roller is controlled according to the type of recording medium. 6. The ink jet recording apparatus according to claim 5, wherein the speed of the discharge roller relative to the speed of the transport roller is controlled according to the size of the recording medium. 7. The ink jet recording apparatus according to claim 6, wherein a speed of the discharge roller with respect to a speed of the transport roller is controlled in accordance with a feeding direction of the recording medium. 8. The recording apparatus according to claim 1, wherein the recording head includes an electrothermal transducer that generates heat energy used for discharging ink.