JP3097235B2 - 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 a recording medium having ink permeability (e.g., a paper sheet) and a recording medium having no ink permeability (e.g., a polymer sheet) by discharging a hot melt ink from an ink jet head. The present invention relates to an ink jet printer that performs printing on both recording media, and in particular, has a heating device that heats a recording medium that does not have ink permeability. The present invention relates to an ink jet printer that can rapidly perform a series of processes from printing on a medium to discharging paper.

[0002]

2. Description of the Related Art Conventionally, printing of characters and the like is performed by discharging a so-called hot-melt type ink having a property of maintaining a solid state at normal temperature and melting when heated to a temperature equal to or higher than a melting point onto a recording medium via an ink jet head. Ink jet printers have been proposed. According to such ink jet printers, not only ordinary paper sheets but also transparent polymer sheets (hereinafter referred to as OHP) for projecting characters and the like printed by an overhead projector or the like.
(Referred to as a sheet).

In such an ink-jet printer, the amount of ink ejected from the ink-jet head is extremely small, and therefore, the heat capacity thereof is small. At this time, in the case of a paper sheet, the adhered ink does not rise so much on the paper sheet because it has ink permeability between paper fibers, but in the case of an OHP sheet, it does not have ink permeability like a paper sheet. The attached ink rises on the OHP sheet.

[0004] The ink raised on the OHP sheet has a convex lens shape. In the case of an OHP sheet on which color characters and the like are printed by a hot melt type ink containing a translucent component, the light irradiated on the OHP sheet by the effect of the convex lens is reduced. Since the image is refracted or dispersed in a complicated manner, images such as clear color characters cannot be obtained. To prevent this, as described in U.S. Pat. No. 4,853,706, the ink once printed on the OHP sheet and then solidified on the OHP sheet is heated again to the melting point or higher, and the ink raised to the convex lens shape is removed. A method of melting and flattening has been proposed.

In an ink jet printer capable of printing on both a paper sheet and an OHP sheet of this type, a heating device is required to perform a flattening process of the ink ejected onto the OHP sheet and raised, and such a heating device is required. It is built into the ink jet printer main body to continuously perform a series of processes from printing to paper discharge.

Conventionally, in an ink-jet printer incorporating the above-described heating device, it is necessary to selectively perform a heating process on the OHP sheet. Therefore, the paper ejection path after printing is a paper sheet ejection path and an OHP sheet ejection path. Although it has a configuration separated into a paper path, the paper ejection device is configured to share a paper sheet and an OHP sheet, and a paper sheet and an OHP sheet are mixed on a recording medium to be printed. OH if
The printing and discharge of the next sheet have been performed after the completion of the process from the heating processing to the discharge of the P sheet.

[0007]

However, the heat treatment of the OHP sheet by the heating device is performed after printing and is relatively time-consuming, so that a series of processes from printing to paper discharge are required. The time required is longer than for paper sheets that do not require heat treatment.

Thus, when printing an image such as a character,
In the conventional ink jet printer, since the paper discharging device is used for both the paper sheet and the OHP sheet, if the OHP sheet is present in the recording medium, the heating device heats the OHP sheet by the heating device as described above. Waiting for the paper discharging process to be completed by the device, the printing process and the paper discharging process for the next sheet are performed. Therefore, it takes time to heat the OHP sheet. There is a problem that the efficiency is reduced. This problem is compounded as the number of OHP sheets to be subjected to the heating process and the sheet discharging process increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is provided upstream of a heating means provided in a paper discharge path of a recording medium having no ink permeability in a paper discharge means. By providing a standby unit for keeping the recording medium on standby, a series of processes from printing of the recording medium having ink permeability to discharge can be performed quickly, thereby improving the processing efficiency of the inkjet printer totally. It is an object of the present invention to provide an ink jet printer capable of performing the above.

[0010]

In order to achieve the above object, the present invention provides a recording medium conveying means for conveying two recording media of different types with respect to the presence or absence of ink permeability, and a recording medium conveyed by the recording medium conveying means. Determining means for determining the type of recording medium, printing means for discharging characters or the like by discharging hot-melt ink on the recording medium, and one of the recording media printed by the printing means having ink permeability A discharge means provided with a first discharge path for discharging the other recording medium having no ink permeability, and a second discharge path for discharging the other recording medium having no ink permeability. Switching means for switching the paper discharge path of the paper discharge means between the first paper discharge path and the second paper discharge path, and heating the other recording medium provided in the middle of the second paper discharge path. Heating means for performing Wherein the a waiting means to keep on standby the other recording medium upstream of the heating means and structure provided with the discharge path.

[0011]

In the present invention having the above construction, first, the type of the recording medium conveyed from the recording medium conveying means is judged by the judging means. When the recording medium is a recording medium having no ink permeability, the paper discharge path of the paper discharging means is switched to the second paper discharging path via the switching means based on the determination result of the determining means, and thereafter the recording medium is printed by the printing means. Characters and the like are printed thereon. After such printing, the recording medium is put on standby by the standby unit, but is sequentially put on standby by the standby unit as long as the recording medium is a recording medium having no ink permeability.

When the discrimination means determines that the recording medium to be printed next is a recording medium having ink permeability, the discharge path of the discharge means is switched to the first discharge path via the switching means based on the discrimination result. The recording medium which has been switched to the paper path and after which printing of characters and the like has been performed by the printing means is discharged from the first discharge path. Such a series of processes is continuously performed as long as the recording medium having the ink permeability continues.

Subsequently, the non-ink permeable recording medium waiting in the standby means as described above is sent through the second paper discharge path and is sequentially heated by the heating means. The sheet is discharged via a sheet discharging path.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side sectional view of the ink jet printer. In FIG. 1, a paper feed cassette 5 holding a stack of print sheets 3 as recording media is detachably provided below the ink jet printer 1 (FIG. 1).
Indicates a state in which the paper feed cassette 5 is mounted). The printing sheet 3 includes a paper sheet made of plain paper having ink permeability and an OHP sheet made of a polyester film sheet having no ink permeability. Each of these sheets is held in the sheet cassette 5 in a stacked state.

A paper feed roller 7 is provided above the position where the paper feed cassette 5 is mounted. Such feed roller 7
Is in contact with the print sheet 3 at the uppermost position of the paper feed cassette 5 mounted on the printer 1 and is rotated by a known paper feed motor to separate the print sheets 3 from the paper feed cassette 5 one by one while Is supplied to the paper feed guide 9.

A pair of paper feed guides 9 is disposed on the right side of the paper feed roller 7 in the figure, and the paper feed guide 9 is a print sheet supplied from the paper feed cassette 5 by the paper feed roller 7. 3 is transported to a print unit 11 (described later) provided downstream of the paper feed guide 9.

A sheet detector 23 is provided at the downstream end of the paper feed guide 9.
Reference numeral 3 designates the type of the printing sheet 3 which has the light emitting diode 23a and the photodiode 23b separated from each other and is fed between the two diodes 23a and 23b, that is, a paper sheet having ink permeability or an ink permeability. Not OHP
This is to detect whether the sheet is a sheet.

When the print sheet 3 fed between the diodes 23a and 23b is a paper sheet, the sheet detector 2
3 detects the light blocking state of the light emitted from the light emitting diode 23a, and determines that the paper sheet has been fed by detecting the light blocking state. When the OHP sheet is fed, the sheet detector 23 detects the transmission state of the light emitted from the light emitting diode 23a. Therefore, it is determined that the OHP sheet has been fed based on the detection of the transmission state.

The printing unit 11 disposed downstream of the sheet detector 23 has an inkjet head 13 for discharging hot-melt type ink onto the print sheet 3 to print characters, figures, and the like. And a sheet holding roller 37, 39 having a pair of rollers at upstream and downstream positions of the inkjet head 13, respectively.

Here, the ink jet head 13 has a plurality of hot melt type inks of a plurality of main colors melted therein, and is driven by a driving device to generate print data input from an external device such as a personal computer. In accordance with this, an ink droplet of a required color is discharged onto the print sheet 3 supported on the platen 15 to print an image such as a character or a graphic on the print sheet 3. Note that the configuration and control procedure of the drive unit of the printing unit 11 have been known in the related art, and a detailed description thereof will be omitted.

The platen 15 supports the print sheet 3 during printing by the ink jet head 13, and a heater is built in the platen 15 so that when printing on a paper sheet, the ink is transferred into the paper sheet. Has been made to promote penetration. Further, the holding roller 37,
Numeral 39 is for holding and positioning the printing sheet 3 during printing by the ink jet head 13.

Next, downstream of the holding roller 39 of the printing unit 11, a paper sheet discharging unit A composed of the discharging guide plate 17 is provided.
And an OHP sheet standby section B composed of standby guide plates 31A and 31B are provided in a branched manner. Discharge guide plate 1
7, a discharge roller 19 and the discharge roller 1
9 is provided with a pinch roller 21 which is pressed against the sheet 9 at a predetermined pressure. The paper discharge roller 19 and the pinch roller 21 cooperate with each other to pinch the paper sheet guided by the paper discharge guide plate 17 therebetween. The paper is discharged outside the ink jet printer 1.

Further, a feed roller 27 and a friction roller 29 pressed against the feed roller 27 at a predetermined pressure are provided at the downstream end of the standby guide plate 31A (the lower part of the back of the print unit 11). , Standby guide plates 31A, 31B,
The feed roller 27 and the friction roller 29 cooperate with each other to
An HP sheet standby unit is configured. In the standby section B, the leading end of the OHP sheet sent along the standby guide plates 31A and 31B is brought into contact with the friction roller 29, guided on the standby guide plate 31A, and waits.

Here, the feeding roller 27 and the friction roller 29
Upstream of the standby guide plate 31B is the standby guide plate 31
A is shorter than A.
A sufficient space is provided on the right side in FIG. 1A so that a plurality of OHP sheets can be stacked and put on standby.

The feeding roller 27 has a sufficiently high friction coefficient with respect to the OHP sheet.
Has a lower coefficient of friction than the feed roller 27, but has a higher coefficient of friction for the OHP sheet. As a result, the feed roller 27 and the friction roller 29 have a so-called friction separating function, and the OH that is on standby by the standby guide plate 31A.
The P sheet is sent from a guide plate 41 to a heating device 33 described later while being separated one by one by both rollers 27 and 29.

The standby guide plate 31 of the OHP sheet standby section B
A heating device 33 is provided downstream of the guide plate 41 that is continuous with A. The heating device 33 is provided with two pairs of guide auxiliary rollers 43 and 45 and a heating platen 35. Each guide auxiliary roller 43, 45 cooperates with each other to
The OHP sheet fed from the P sheet standby unit B is guided in the heating device 33, and the heating platen 35 is maintained at a temperature slightly higher than the melting point of the hot melt type ink and discharged onto the OHP sheet. The heated and solidified ink is heated again to perform flattening processing of the melted and raised ink.

Further, a guide plate 47, a guide auxiliary roller 49, and a paper discharge guide plate 51 are provided downstream of the heating device 33, and the OHP sheet heated by the heating device 33 through these components is provided. The paper is fed between the paper discharge roller 19 and the pinch roller 21.

A paper discharge tray 53 is provided below the paper discharge roller 19, and the paper discharge roller 19 and the pinch roller 21 are provided.
The paper sheet and the OHP sheet discharged by the above are stacked on the paper discharge tray 53.

The discharge guide plate 17 and the standby guide plate 31
A diverter 25 is disposed at a branch point between the A and 31B so as to be rotatable about a shaft 26. The diverter 25 is a part of a guide path to the paper sheet discharge unit A and the OHP sheet standby unit B. The position is switched between a solid line position (paper sheet discharge position) and a broken line position (OHP sheet feeding position) in FIG. 1 via a solenoid (not shown) based on the detection result of the sheet detector 23.

Thus, when the print sheet 3 fed from the paper feed cassette 5 is detected by the sheet detector 23 as a paper sheet, the diverter 25 is rotated about the shaft 26 and shown in FIG. The paper sheet switched to the solid line position and printed by the ink jet head 13 is guided from the sheet holding roller 39 to the paper discharge guide plate 17, and is discharged by the paper discharge roller 19 and the pinch roller 21 to the paper discharge tray 3.
7 is discharged.

When the print sheet 3 fed from the paper feed cassette 5 is detected by the sheet detector 23 as an OHP sheet, the diverter 25 is rotated about a shaft 26 and is indicated by a broken line in FIG. The OHP sheet, which has been switched to the position, and printed by the inkjet head 13, is guided by the sheet holding roller 39 between the standby guide plates 31A and 31B, and is accumulated on the standby portion B by cooperation with the feed roller 27 and the friction roller 29. Waiting at

Next, a control system of the ink jet printer 1 configured as described above will be described with reference to FIG. FIG. 2 is a block diagram of the ink jet printer 1.
Control is performed with 1 as a nucleus.

In FIG. 2, a CPU 63 has a RAM 63.
The RAM 63 is for temporarily storing various data calculated by the CPU 61, such as a print buffer for storing print data to be printed on the print sheet 3 by the print head 13. have.

A ROM 65 is connected to the CPU 61. The ROM 65 has programs necessary for various controls of the ink jet printer 1, for example, a print control program for controlling printing of the ink jet head 13,
Rotation control of the feed roller 7, rotation control of the diverter 25,
Programs necessary for controlling the heating of the heating platen 35 are stored, and the CPU 61 executes various controls based on these control programs.

The paper feed roller 7 is connected to the CPU 61 via a paper feed control circuit 67, and the CPU 61 drives the rotation of the paper feed motor via the paper feed control circuit 67 to control the rotation of the paper feed roller 7. I do.

Further, the ink jet head 13 is connected to the CPU 61 via a print head drive circuit 69. The CPU 61 controls the ink jet head 13 via the print head drive circuit 69 based on a print control program stored in the ROM 65. The hot melt type ink is driven from the ink jet head 13 according to the print data stored in the print buffer of the RAM 63 according to the print data.
Prints characters and the like by discharging upward.

Further, the diverter 25 is connected to the CPU 61 via the sheet detector 23 and the diverter control circuit 71. The CPU 61 drives the solenoid by the diverter control circuit 71 based on the detection signal from the sheet detector 23 to drive the diverter 25. Is controlled.

The CPU 61 has a friction separation control circuit 73.
The OHP sheets waiting in the OHP sheet standby section B are sequentially sent one by one from the guide plate 41 to the heating device 33 via the heating process control circuit 75, and the heating platen 35 Is controlled so as to always maintain a temperature equal to or higher than the melting point of the hot melt ink.

The thermistor 7 connected to the CPU 61
7 is for detecting the temperature of the heater built in the platen 15, and the CPU 61 is provided with the thermistor 77.
Is to control the temperature of the heater in the platen 15 based on the detection result.

Next, the operation of the ink jet printer 1 configured as described above will be described with reference to FIG. FIG. 3 is a flowchart of a sheet feeding control program for the print sheet 3. In step 1 (hereinafter abbreviated as S), first, when a printing start switch is pressed, the sheet feeding roller 7 starts to rotate, and The uppermost print sheet 3 stacked on the paper cassette 5 is sent via the paper feed guide 9 toward the print unit 11.

Next, at S2, when the print sheet 3 thus sent passes between the light emitting diode 23a and the photodiode 23b of the sheet detector 23, the type of the sheet is detected. If the sent print sheet 3 is a paper sheet, the light shielding state of the light emitted from the light emitting diode 23a is detected, and the process proceeds to S3, and based on the detection result, the diverter 25 sets the diverter control circuit 7
1 and is switched to the position indicated by the solid line in FIG. Thereafter, the paper sheet is sent upward while being nipped by the sheet holding roller 37, and is also nipped by the other sheet holding roller 39 and supported by the platen 15.

Next, at S4, the print head drive circuit 6
The ink jet head 13 is driven via the sheet 9 and hot melt ink droplets of a predetermined color are ejected onto the paper sheet while feeding the paper sheet upward by the sheet holding rollers 39 and 41, thereby performing desired printing of characters and the like. Will be At this time, the heater incorporated in the platen 15 is maintained at a constant temperature via the thermistor 77, and the hot-melt ink discharged on the paper sheet is thereby promoted to penetrate into the paper sheet between the paper fibers. Is done.

After the printing is completed, in S5, the paper sheet is sent along the paper discharge guide plate 17 while being guided by a part of the diverter 25 by the sheet holding roller 39, and then the paper sheet is moved between the paper discharge roller 19 and the pinch roller 21. The paper is discharged to the paper discharge tray 53 by cooperation.

On the other hand, if the print sheet 3 fed from the paper feed cassette 5 via the paper feed roller 7 is an OHP sheet, the transmission state of the light emitted from the light emitting diode 23a by the sheet detector 23 in S2. Is detected, so S
The diverter 25 then proceeds to the axis 26 via the solenoid by the diverter control circuit 71 based on the detection result.
And is switched to the position indicated by the broken line in FIG.

Thereafter, in step S7, as in the case of the paper sheet, the OHP sheet is sent upward while being held by the sheet holding rollers 37 and 39, supported by the platen 15, and placed on the OHP sheet via the ink jet head 13. Hot melt ink droplets are ejected to perform desired printing of characters and the like.

Next, in S8, the print data following this is R
It is determined whether it is in the AM 63 or not, and if there is still print data, the process proceeds to S9 where the OHP sheet is waited in the OHP sheet waiting section B. Thereafter, returning to S2, the type of the print sheet 3 is detected again by the sheet detector 23. As a result of the detection, if the next print sheet 3 is an OHP sheet, the above-described steps S6, S7 and S8 are executed, and as long as the print sheet 3 is an OHP sheet, such OHP sheets are sequentially waited in the OHP sheet standby section B. Go.

In S8, the next print data is stored in the RAM 63.
If it does not exist, the process proceeds to S10, where the OHP
The sheet is fed to the feed roller 27 via the friction separation control circuit 73.
Is driven into rotation and fed into the heating device 33 from the guide plate 41. In the following S11, the OHP sheet is sent in the direction of the heating platen 35 by the guide auxiliary rollers 43 and 45, and is discharged onto the OHP sheet by the heating platen 35 whose heating is controlled via the heating processing control circuit 75 and solidified in a raised state. The hot-melt type ink is melted again and the ink is flattened.

After the flattening process of the ink by the heating platen 35, the OHP sheet is sent to be discharged by the guide plate 47, the guide auxiliary roller 49, and the discharge guide plate 51 in S5, and is discharged. The paper is discharged to the paper discharge tray 53 by the cooperation of the pinch roller 21.

As described above in detail, in the ink jet printer 1 according to the present embodiment, the type of the print sheet 3 is detected by the sheet detector 23, and the diverter 25 is selectively rotated based on the detection result, thereby forming the paper sheet. And an OHP sheet to select a paper discharge path,
An OHP sheet standby section B including standby guide plates 31A and 31B, a feed roller 27 and a friction roller 29 is formed upstream of a heating device 33 provided in the middle of the OHP sheet discharge path. Even in the case where the sheet and the OHP sheet are mixed, the printing process and the discharging process of the paper sheet can be preferentially performed before the flattening process of the ink on the OHP sheet by the heating platen 35 which takes a relatively long time. .

Therefore, unlike the conventional ink jet printer, it is not necessary to perform the printing process and the paper discharging process of the paper sheet after the completion of the heating process and the paper discharging process of the OHP sheet. Can be totally improved without lowering.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention.

[0052]

As described above, according to the present invention, the standby means for keeping the recording medium on standby upstream of the heating means provided in the discharge path of the recording medium having no ink permeability in the paper discharging means. The present invention provides an ink jet printer that can rapidly perform a series of processes from printing of a recording medium having ink permeability to discharge of paper, thereby improving the processing efficiency of the ink jet printer in total. It has a great industrial effect.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ink jet printer.

FIG. 2 is a block diagram of the ink jet printer.

FIG. 3 is a flowchart of a print sheet feeding control program.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inkjet printer 3 print sheet 7 paper feed roller 9 paper feed guide 11 print unit 13 inkjet head 17 paper discharge guide plate 23 sheet detector 25 diverter 27 feed roller 29 friction roller 31A, 31B standby guide plate 33 heating device 35 heating platen 41, 47 guide plate 51 discharge guide plate

Claims (1)

(57) [Claims] 1. A recording medium transport unit that transports two recording media of different types with respect to the presence or absence of ink permeability, a determination unit that determines a type of a recording medium transported by the recording medium transport unit, and the recording medium A printing unit that discharges a hot-melt ink on the top to print characters and the like, and a first paper discharge path that discharges one of the recording media printed by the printing unit that has ink permeability, A paper discharging means provided with a second paper discharging path for discharging the other recording medium having no ink permeability, and a paper discharging path of the paper discharging means based on a result of the discrimination by the discriminating means. Switching means for switching between the first discharge path and the second discharge path; heating means provided in the middle of the second discharge path for heating the other recording medium; and heating in the second discharge path. Said other upstream of the means An ink-jet printer provided with a standby unit for holding one of the recording media.