JPH09169121A - Inkjet printer - Google Patents

Abstract

(57) Abstract: In an inkjet printer that also serves as a paper transport drive source and a pump drive source, it is possible to suppress deterioration of print quality due to a drive source switching operation. A pump drive unit (1) forcibly discharging ink in an ink container (10) that stores maintenance discharge ink.
In the ink jet printer 1 which also functions as the print sheet transport driving unit 13, the counting unit 2 that counts the amount of ink ejected into the ink container 10, the holding unit 3 that holds this count value A, and the drive execution of the pump. Storage unit 4 for storing a permissible execution value B and a compulsory execution value C (B <C) required to compulsorily execute a pump, and a judgment unit for judging whether or not print data is connected and printed. 5 and a pump drive control means 6 that outputs a control signal for pump drive when the count value A is B ≦ A <C and there is no connection of print data according to the determination result of the determination means 5. To configure.

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 having both a drive motor for conveying printing paper and a motor for driving an ink discharge pump.

[0002]

2. Description of the Related Art An ink jet printer prints by ejecting dots by ejecting a dedicated ink onto a printing paper from an ink jet nozzle. For this reason, a plurality of small diameter nozzles are formed in the inkjet nozzle.

Although these nozzles have a very small diameter and use a dedicated ink, they are apt to be clogged due to drying of the ink or the like. Therefore, in order to maintain the ink ejection accuracy during continuous printing, the inkjet printer performs a "flushing operation", which is an "ink ejection operation for purposes other than printing", at certain time intervals. This flushing operation cannot be executed at any position because ink is ejected from the inkjet nozzles, and is usually a container for storing ejected ink (hereinafter referred to as an ink container) disposed near the accommodating position of the carriage. Done against.

However, the storage amount of the ink container is physically limited, and it is necessary to discharge the ink container before it overflows. Specifically, before the ink container overflows, a pump connected to the ink container is driven to discharge the ink accumulated in the ink container to the outside of the container. As described above, the inkjet printer requires a drive source for driving the pump in order to discharge the ink in the ink container.

By the way, a printer device including an ink jet printer is always provided with a drive source for carrying a printing sheet to be printed. That is, the drive source for transporting the printing paper is also used as the drive source of the pump described above, whereby the cost can be suppressed.

FIG. 5 shows a PF (Paper Fe) for conveying printing paper.
ed) is a main-portion cross-sectional view showing an example of the operation switching mechanism when the motor is also used as the pump drive source.

The operation switching mechanism 11 is roughly composed of a main drive source 12, a transport drive section 13, and a pump drive section 14. The main drive source 12 is a PF motor 15, a PF gear 1
6, a drive gear 17, a disengagement gear 18, and a P mounted on the rotary shaft of the PF motor 15.
The rotation of the PF motor 15 is driven by the F gear 16 to drive the gear 1.
It is transmitted to the disengagement gear 18 via 7.

The disengagement gear 18 is movably provided in the left-right direction in FIG. 5 by an actuator (not shown), and transmits the driving force to either the transport drive unit 13 or the pump drive unit 14. is there.
That is, with respect to the transport drive unit 13, the dock clutch 18a formed at the tip of the shaft of the gear is connected to the drive gear 1 described later.
The driving force is transmitted to the pump driving unit 14 by meshing with the dock clutch 19a formed on the shaft 9, and by coupling the gear portion with a pump gear 22 described later.

The transport drive unit 13 is composed of a drive gear 19, a platen gear 20, and a platen roller 21, and the rotation transmitted from the dock clutch 18a portion of the disengage gear 18 in the normal operation state is driven by the drive gear 19 and the platen gear. It is transmitted to the platen roller 21 via 20 to carry and feed the printing paper.

The pump drive unit 14 is a pump drive gear 2
2, 23, 24 and the pump gear 25, and in the pump driving operation state, the rotation transmitted from the disengagement gear 18 is transmitted to the pump gear 25 via the pump driving gears 22, 23, 24, and a pump (not shown) is driven. It is driven.

In FIG. 5, reference numeral 26 is a right frame for supporting and fixing the PF motor 15, and 27 is a right frame 26.
It is an intermediate frame that also supports the drive gear 17. Reference numeral 28 is a bearing bearing of the platen roller 21.

In the above structure, during normal operation, the dock clutch 18a of the disengagement gear 18 meshes with the dock clutch 19a of the drive gear 19, and P
The rotational driving force of the F motor 15 is supplied to the conveyance driving unit 13, and the platen roller 21 rotates to perform a sub-scanning operation (conveyance of the printing paper and paper feeding) accompanying the main scanning operation of the inkjet nozzle.

As described above, the ink jet printer performs the flushing operation on the ink container at a certain time interval (for example, every sub-scanning operation) in order to maintain the accuracy of ink ejection during continuous printing. Then, when a predetermined amount of ink is accumulated in the ink container by the flushing operation, the operating state is shifted from the normal operating state to the pump driving operating state before overflow.

When the pump drive operation state is reached, the actuator of the disengagement gear 18 is operated to set P
The rotation of the F motor 15 is transmitted to the pump, and the ink accumulated in the ink container is discharged.

By the way, for example, in the case of printing continuous image data, if the operating state is changed between the normal operating state and the pump driving operating state during printing, the transport driving unit 1
The operation of 3 becomes unstable and the sub-scanning pitch shifts,
There is a problem that prints with connected images may be separated or may overlap. This is a serious problem that occurs in an inkjet printer in which the main drive source 12 is used for both the sub-scanning operation and the pump driving in order to reduce the cost, which is a major obstacle in printing high quality image data.

For this reason, in the conventional ink jet printer, the pump drive operation state is set such that the ink container is set to the timing from the completion of the print output of one sheet to the start of printing on the next print sheet. The above problem was dealt with by setting the capacity.

[0017]

Conventionally, as a printing paper used in an ink jet printer, for example, B5 is used.
Cut sheets of A4 size or A4 size were generally used. That is, the timing of the above-described pump drive operation state is set for the flushing operation performed while printing out one sheet for a cut sheet of a sheet size (for example, A4 size) that is mainly used by the printer. ,
It suffices to prepare an ink container having a sufficient capacity.

However, in the recent printing environment in which various kinds of print output media and paper sizes have come to be used, for example, for a paper of A2 width and several meters long, There is also provided a printer capable of performing so-called banner printing. When printing is performed on a printing paper of such a large size, it is inevitable that the capacity of the conventional ink container shifts to the pump drive operation state during printing.

In such a case, the easiest measure is to equip the printer with an ink container having a capacity sufficient for the printing paper. However, increasing the capacity of the ink container means increasing the size of the container, and it is not preferable that the space inside the printer be occupied by the ink container that is not directly related to printing itself.

Also, with the recent flow of the printing environment, it is considered that the paper size will be further lengthened in the future, which also suggests that it is difficult to set the maximum capacity of the ink container.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to suppress deterioration of print quality due to switching operation of a driving source in an ink jet printer which also serves as a driving source for transporting printing paper and a driving source for a discharge pump. To provide a printer device.

[0022]

SUMMARY OF THE INVENTION The present invention has a pump drive which has an ink container for storing ink ejected from an inkjet nozzle for maintenance and forcibly discharges the ink stored in the ink container at regular time intervals. In an inkjet printer that also serves as a transport drive unit that transports a printing sheet, a counting unit that counts the amount of ink ejected into the ink container, a holding unit that holds the count value A counted by the counting unit, and A storage unit that stores an execution permission value B, which is a threshold value for permitting the drive execution of the set pump, and a compulsory execution value C (however, B <C), which is a threshold value for performing the compulsory execution of the pump. , A judgment means for judging whether or not the print data is connected and printed, and the count value A held in the holding means. When B ≦ A <C, is configured with a pump drive control means for outputting a control signal for driving of the pump when there is no connection of the print data from the judgment result of said judgment means.

As the determination method by the determination means, an extraction unit for extracting the maximum paper feed amount connected to the image data to be printed from the current print mode, the maximum paper feed amount extracted by the extraction unit, and the present And a comparison unit for comparing the paper feed amount of, and the comparison result of the comparison unit,
When the current paper feed amount is smaller, it can be considered that print data is not connected.

Further, the execution permission value B stored in the storage means is an arbitrary value, and the execution permission value B is set to an optimum value on the basis of the information regarding the size of the printing paper transferred from the host. It is effective to do. For example, when the paper size to be printed is sufficiently small, the value is increased to reduce the number of times of pump driving, and conversely, when the paper size is large, the value is decreased to reduce the execution permission value B.
It is conceivable to widen the operation margin by increasing the range from to the forced execution value C.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the functions of the essential parts of the ink jet printer of the present invention. The configuration of the operation switching mechanism according to the present invention is the same as that of the conventional example shown in FIG. 5, and the driving force of the main drive source 12 is transferred by the operation switching mechanism 11 shown in FIG.
To either of them.

As shown in FIG. 1, the ink jet printer 1 of the present invention is provided with the main drive source 12, the transport drive section 13, the pump drive section 14 as described above, and further, the counting means 2, the holding means 3, The storage unit 4, the determination unit 5 having the extraction unit 5a and the comparison unit 5b, and the pump drive control unit 6 are provided.

The counting means 2 measures the amount of ink ejected from the ink jet nozzle into the ink container 10, that is,
The number of ink ejections associated with the flushing operation is counted. The holding unit 3 stores and holds the number of ejections counted by the counting unit 2 as a count value A, and the ink container 1 is held by the count value A.
The approximate amount of ink ejected with respect to 0 can be known.

The storage means 4 stores a threshold value for the amount of ink stored in the ink container 10, and more specifically, an execution permission value B which is a threshold value for permitting the execution of the pump drive section 14. And a forced execution value C (provided that B <C), which is a threshold value for performing the forced execution of the pump drive unit 14, are stored.

The judging means 5 judges whether or not the print data to be printed are connected and printed.
In this example, as an example of the determination method, the extraction unit 5a that extracts the maximum paper feed amount connected to the image data to be printed from the current print mode, the maximum paper feed amount extracted by the extraction unit 5a, and the current paper feed amount. A comparison unit 5b for comparing the feed amount is provided, and it is determined that the print data is not connected when the current paper feed amount is smaller than the comparison result by the comparison unit 5b.

FIG. 2 shows table data when the maximum paper feed amount to which image data is connected is extracted from the current print mode.

In FIG. 2, the ink jet printer 1 in this example has a resolution of 360 DPI (Dot Per Inch) and 720 DPI, and high-definition microweave printing (MW in FIG. 2) and normal printing. The non-microweave printing (NMW in FIG. 2) that is the above can be selectively executed. Furthermore, by selecting monochrome printing and color printing, there are a total of eight print modes. That is, the extraction unit 5a can obtain information on the maximum paper feed amount by detecting which of the eight print modes the current print mode is.

In the example shown in FIG. 2, in the case of monochrome printing,
120 steps for character printing or 360 DPI-NMW, 58 steps for 360 DPI-MW, 720DP
I-NMW requires 129 steps, and 720DPI-MW requires 29 steps. On the other hand, in the case of color printing, 116 steps in character printing or 360 DPI-NMW,
40 steps for 360 DPI-MW, 720 DPI-
115 steps for NMW, 1 for 720DPI-MW
There are 9 steps.

The pump drive control means 6 is the main drive source when the count value A held in the holding means 3 is within the range of B≤A <C when there is no print data connection from the judgment result of the judgment means 5. It outputs a control signal for switching the power of 12 from the transport drive unit 13 to the pump drive unit 14.

Next, the operation of the above embodiment will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 3 is a flow chart for explaining the flushing operation process. FIG. 3 (a) shows an interrupt process of the flushing operation, and FIG. 3 (b) shows an overall process outline of the flushing operation. In FIG. 3, S indicates a processing step.

If the interval interrupt processing in this example is to occur every 10 msec, for example, as shown in FIG. 3A, the flushing timer variable FLSTIMR is incremented for each interrupt time interval (S1). . On the overall processing side shown in FIG.
First, the flushing timer variable FLSTIMR is compared with a preset flushing timer constant FLTIME (S2). Here, the flushing timer constant FLT
IME is a constant for setting a time interval at which a flushing operation is desired to be performed.
c) will do.

When the value of the flushing timer variable FLSTIMR becomes equal to or more than the value of the flushing timer constant FLTIME in the determination processing of S2, the carriage having the ink jet nozzle is moved to the accommodation position of the carriage (S3).

Next, a flushing operation is performed on the ink container 10 (S4). Then, the constant FLINK corresponding to the amount of ink newly stored in the ink container 10 by the flushing operation is set to the count value A which is the ink amount variable.
(S5), and the flushing timer variable FLSTI
The MR value is reset to "0" (S6).

In the determination process of S2, when the flushing operation is performed, after performing the flushing operation,
If the flushing operation is not performed, printing is immediately executed (S7).

FIG. 4 is a flow chart for explaining the pump drive processing.

In the pump drive process, first, based on the table data shown in FIG. 2, the maximum paper feed amount corresponding to the current print mode is obtained, and the value of the maximum upper paper feed amount is set in the image height variable IMGHGT. Substitute (S11). next,
The count value A and the forced execution value C are compared (S12), and A
If <C, then the count value A and the execution permission value B are compared (S13). If A ≧ B, the variable PFSTEP indicating the current paper feed step amount is compared with the image height variable IMGHGT (S14).

Here, in the determination processing of S12,
If A> C, or if PFSTEP> IMGHGT in the determination process of S14, a control signal is output from the pump drive control means 6 and the power of the main drive source 12 is transferred to the transport drive unit 13. To pump drive 14
And the pump is driven (S15).

That is, when the amount of ink stored in the ink container 10 has reached the limit, discharge is given first priority in order to prevent ink overflow, and even if the print image is connected, it is forced. To drive the pump.

On the other hand, in the judgment processing of S13, A
If <B, or if PFSTEP ≦ IMGHGT in the determination process of S14, it is determined that there is still free space in the ink container 10 or that the image being printed is connected. And above S
The processing of 15 is passed. Then, regardless of whether or not the pump is driven, the paper feed of the predetermined amount determined by the variable PFSTEP is finally executed, and the process ends (S1).
6).

As described above, in the present invention, the ink container 10 is used.
Amount of ink stored inside (that is, count value A)
However, when the limit of the container capacity is not reached but the execution permission value is equal to or more than B, the maximum paper feed amount connecting the images from the current print mode is calculated, and this value is compared with the current paper feed amount. By doing so, it is determined whether or not the print images are connected, and when it is determined that they are not connected, the pump drive is executed.

As a result, even when printing is performed on a long size printing sheet with the ink jet printer 1 in which the main driving source 12 is also used as the transport driving section 13 and the pump driving section 14, the printing quality is deteriorated. It can be significantly reduced.

[0048]

As is apparent from the above description, according to the present invention, in an ink jet printer in which a drive source for transporting a print sheet also serves as a drive source for a discharge pump, the drive source is switched at a portion where a print image is connected. It is possible to reduce the number of operations as much as possible, and further it is possible to reduce the deterioration of print quality due to the switching operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing functions of main parts of an inkjet printer of the present invention.

FIG. 2 is a diagram showing table data when a maximum paper feed amount to which image data is connected is extracted from a current print mode.

FIG. 3 is a flowchart illustrating a flushing operation process.

FIG. 4 is a flowchart illustrating a pump drive process.

FIG. 5 is a cross-sectional view of essential parts showing an example of an operation switching mechanism when a PF motor for transporting printing paper also serves as a pump drive source.

[Explanation of symbols]

 1 Inkjet Printer 2 Counting Means 3 Holding Means 4 Storing Means 5 Judging Means 5a Extracting Section 5b Comparing Section 6 Pump Drive Controlling Means 10 Ink Container 11 Operation Switching Mechanism 12 Main Driving Source 13 Conveying Drive 14 Pump Drive 15 PF Motor 16 PF Gear 17 Drive Gear 18 Disengage Gear 19 Drive Gear 20 Platen Gear 21 Platen Roller 22-24 Pump Drive Gear 25 Pump Gear 26 Right Frame 27 Middle Frame 28 Bearing Bearing

Claims (3)

[Claims] 1. A printing paper is conveyed by a pump drive unit that has an ink container that stores ink discharged from an inkjet nozzle for maintenance, and that forcibly discharges the ink stored in the ink container at regular time intervals. In an inkjet printer that also serves as a transport drive unit, a counting unit that counts the amount of ink ejected into the ink container, a holding unit that holds a count value A counted by the counting unit, and a preset drive of the pump. The print data is connected to a storage unit that stores an execution permission value B that is a threshold value for permitting execution and a forced execution value C (B <C) that is a threshold value for performing forced execution of the pump. Determination means for determining whether or not the count value A held in the holding means is B ≦ A <C
And if there is no print data connection according to the determination result of the determination unit, or if the count value A is A ≧ C, a pump drive control unit that outputs a control signal for driving the pump. An inkjet printer, comprising: 2. The determining unit extracts an maximum paper feed amount connected to image data to be printed from a current print mode, a maximum paper feed amount extracted by the extraction unit, and a current paper feed amount. The comparison unit that compares the print data and the print data are compared with each other when the current paper feed amount is smaller than the comparison result of the comparison unit. Inkjet printer. 3. An execution permission value B stored in the storage means.
Is an arbitrary value, and the execution permission value B is set on the basis of information regarding the size of the printing paper transferred from the host.