JPH09300724A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a recorder by a controller so that an image is printed deeply or boldly by the recorder when the moving speed is slower than a preset reference speed as a result of comparison by a speed comparator provided. SOLUTION: Printing operation is started and electric signals corresponding to the scanning speeds are issued by an encoder 11 and input to a speed comparing processor 5 that compares the electric signals with a reference speed and outputs comparison signals. When the print scanning of an apparatus is detected, a controller 14 receives the comparison signals from the speed comparing processor 5. When the scanning speed is higher than the reference speed, the controller 14 reads out image information stored in a memory 16 in turn simultaneously with the electric signals and transfers them to a drive 17. The controller 14 transfers the image information stored in the memory 16 to the driver 17 for every number of nozzles of an ink-jet recording head 43 and sends every pixel of the image information to the driver 17 twice to print twice. Thereby, the image can be printed more boldly or deeply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus that prints by scanning a recording medium, and more particularly to an image forming apparatus that controls printing according to the scanning speed.

[0002]

2. Description of the Related Art Conventionally, in a manually scanned image forming apparatus, the speed at which it moves on a recording medium is not constant. Therefore, as shown in, for example, Japanese Patent Laid-Open Publication No. 48-17630, the print head is not covered. A displacement detection device for detecting a relative position change with respect to the recording medium is provided. In this displacement detection device, a change in the relative position caused by the print head moving on the recording medium is performed by rotating a roller that moves together with the print head on the recording medium. That is, by detecting the rotation angle of the roller, the relative position change between the print head and the recording medium is detected, and the position of the print head is detected.

As described above, in the conventional image forming apparatus, the displacement detecting device detects the relative position change between the print head and the recording medium, and controls the print head in synchronization with the detection result, so that the moving speed is constant. Good printing can be performed even when it is not. Therefore, the image forming apparatus having such a configuration can easily perform printing at an arbitrary position on the recording medium, for example, printing on a thick book or document that has been bound or a large size sheet. It has the feature of being able to.

[0004]

However, in the conventional image forming apparatus, when it is desired to thicken the image to be printed, it is necessary to prepare the image data for the thick image, which results in an increase in the total data amount. There is a problem that it ends up.

Further, when it is desired to darken an image to be printed, the pixels forming the image are printed twice (overprinting).
There is a method to do this, but in that case, once printing and 2
A changeover switch or the like for changing over and over printing is required, and there is a problem that it is difficult to arrange the switch especially in a downsized apparatus such as a manual image forming apparatus.

The present invention has been made to solve the above-mentioned problems, and it is possible to increase the number of image data without increasing
Another object of the present invention is to provide an image forming apparatus that can print an image thick or dark without requiring a special switch or the like.

[0007]

In order to achieve this object, in the image forming apparatus according to claim 1 of the present invention,
Recording means for printing an image on a recording medium, speed detecting means for detecting a relative moving speed of the recording means and the recording medium, and synchronously with the moving speed detected by the speed detecting means. In an image forming apparatus having a control means for driving the recording means, the speed comparison means compares the moving speed detected by the speed detection means with a preset reference speed,
When it is determined that the moving speed is slower than the preset reference speed, the control unit controls the image printed by the recording unit to be thick or dark.

Further, in the image forming apparatus according to a second aspect, when the control means determines that the moving speed is slower than the preset reference speed by the speed comparing means, each pixel forming the image to be printed is selected. Print multiple times.

The image forming apparatus according to claim 3 is
The reference speed is set to be equal to or lower than the speed obtained by dividing the maximum drive speed of the recording means by the number of times of printing.

Further, in the image forming apparatus according to the fourth aspect, the reference speed setting means arbitrarily sets the reference speed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view showing the external appearance of the image forming apparatus of this embodiment. The body portion 1 of the image forming apparatus is
It has a cylindrical shape and is configured so that the operator can easily support it by hand. The roller 42 is rotatably provided at the tip of the body 1. The surface of the roller 42 is made of an elastic material such as rubber. An inkjet recording head 45 is arranged beside the roller 42.
The inkjet recording head 45 constitutes the recording means of the present invention. At the other end of the body portion 1, an interface portion 3 for infrared communication for transmitting / receiving print data to / from an external device (not shown) is provided.
Further, on the side surface of the body portion 1, a mode selector switch 4 for switching the operation mode (data input mode / printing mode) of the image forming apparatus is provided. The mode switch 4 also serves as a power switch for turning on and off the power of the image forming apparatus.

That is, in the image forming apparatus according to the present embodiment, the operator holds the body 1 with the print data and the like input from the external device and rotates the roller 42 in contact with the recording medium (paper or the like). This is a device for performing predetermined printing on a recording medium by manually scanning while performing.

FIG. 2 is an internal configuration diagram for explaining the internal configuration of the image forming apparatus of this embodiment. Figure 2 below
The internal configuration of the image forming apparatus of this embodiment will be described in detail with reference to FIG.

At the tip of the body portion 1, a roller 42 is constructed so as to be rotatable around the shaft 8. An inkjet recording head 45 is arranged beside the roller 42. The ink jet recording head 45 is arranged such that the front end portion of the recording medium (paper) has a constant gap.

An ink tank 7 for supplying ink to the ink jet recording head 45 is arranged above the ink jet recording head 45.

A pulley 9 is arranged on the rotation center shaft 8 of the roller 42 so as to rotate with the rotation of the roller 42. A belt 10 is drawn around the pulley 9, and is configured to transmit the rotational force of the pulley 9 that rotates with the rotation of the roller 42 to a rotating disk 12 of an encoder 11 described later. The encoder 11 is arranged near the center of the body portion 1. The rotating disk 12 is provided with slits 12a and 12b on the circumference at predetermined intervals, and the rotating disk 12 is rotated by the photo interrupter 13 of the encoder 11 which is turned on / off by the rotation of the slits 12a and 12b. It is configured to convert the speed into an electric pulse signal and input the electric pulse signal to the control unit 14 described later. The slit 12b is formed with a 90 ° phase shift with respect to the slit 12a. Therefore, encoder 1
1 constitutes the speed detecting means of the present invention.

On the side opposite to the roller 42 of the body 1, the above-mentioned ink jet recording head 45, the electric pulse signal of the photo interrupter 13, and the interface section 3 and the like provided for receiving print data from the outside, which will be described later, etc. A control unit 14 for controlling is arranged.
Further, a power source 15 for supplying electric power to each functional block described later is arranged in the vicinity thereof. The power supply 15 is composed of a power supply unit such as a small primary battery or a secondary battery and a device for stabilizing the power.

Next, a method of detecting the movement amount and the movement direction in the encoder 11 when the image forming apparatus of the present embodiment is manually scanned will be described with reference to FIG.

The roller 42 is rotated by scanning the recording medium with this image forming apparatus. FIG. 3 shows the roller 4
2 is for explaining the detection waveform of the photo interrupter 13 in the case of the rotation direction of the right direction and the left direction of 2. In the case of the right rotation, the detection waveform of the slit 12b is the slit 12a as shown in the figure. The phase is detected delayed by 90 ° with respect to. Further, in the case of counterclockwise rotation, the detection waveform of the slit 12b is detected in a state in which the phase leads the detection waveform of the slit 12a by 90 °. Therefore, the rotational direction of the roller 42 can be detected by detecting the phase shift between the two waveforms. Further, by counting the number of pulses of the detection waveform of the photo interrupter 13, the movement amount of the image forming apparatus can be detected.

FIG. 4 is a functional block diagram showing the electrical configuration of the image forming apparatus of this embodiment. In the figure, a control unit (microcomputer) 14 is connected to a storage device 20 (ROM) containing a control program for controlling each functional block according to a predetermined program.
The interface unit 3 and the mode changeover switch 4 described above are connected to the control unit 14. Further, the signal after the rotation speed of the encoder 11 is converted into the electric pulse signal is input to the control unit 14, and
It is also configured to be input to the speed comparison processing unit 5 described later. Further, a storage unit (RAM) 16 for storing print data input from the interface unit 3 and a drive unit 17 for driving the inkjet recording head 45 are similarly connected to the control unit 14. Each of these functional blocks is built in the body 1 of the image forming apparatus shown in FIG. The speed comparison processing section 5 is the speed comparison means of the present invention, and the control section 14 is the control means of the present invention.

Next, a detailed configuration of the speed comparison processing section 5 in the image forming apparatus of the present embodiment will be described with reference to FIG.

The electric signal (FIG. 3) whose rotational speed has been converted by the encoder 11 as described above is guided to the frequency / voltage converter 51 (hereinafter referred to as F / V converter). F
The voltage v corresponding to the frequency of the input signal is output from the / V converter 51 to the level comparator 52. This voltage v is compared in the level comparator 52 with a preset reference voltage v1. Here, the reference voltage v1 is obtained by converting a preset reference speed into a voltage. The level comparator 52 outputs a high-level comparison signal when the value of the voltage v exceeds the value of the reference voltage v1, and outputs a low-level comparison signal when the value of the voltage v is smaller than the value of the reference voltage v1. Since it is configured to output, it can be determined whether the scanning speed exceeds the reference speed. The reference speed is set to be equal to or less than half of the maximum driving frequency (speed) of the inkjet recording head 45.

The operation of the image forming apparatus of the present embodiment having the above configuration will be described based on the flowchart of FIG.

The image forming apparatus of this embodiment operates according to a predetermined program stored in the storage device 20 described above. First, when the switch 4 is set to the input mode (step 1: Y, hereinafter referred to as S1; other steps are the same), the control unit 14 determines that the print data can be input from the external device, and the print data is input. Waits for an input from the external device to the interface section 3 by an infrared signal (S2). When the control unit 14 detects the input of print data (S2: Y), the print data is temporarily stored in the storage unit 16 (S3). At this time, the control unit 14 converts the print data input from the external device into a data format that can be easily printed by the recording unit 45 and stores the data in the storage unit 16. It is possible to reduce the print processing load.

Next, when the print mode is designated by the switch 4 (S1: Y), the control unit 14 determines whether or not the print data is already stored in the storage unit 16, and the storage unit 1
If print data is not stored in 6 (S4:
N), the subsequent processing is stopped. On the other hand, when print data is already stored in the storage unit 16 (S4: Y), the operator waits for the apparatus to be gripped and print-scanned on the recording medium (S5).

Then, the operator starts printing scanning, an electric signal corresponding to the scanning speed is generated from the encoder 11, the electric signal is input to the speed comparison processing section 5, and the speed comparison processing section 5 is preset. The comparison signal is output depending on whether or not the reference speed is exceeded.

When the control unit 14 detects that the printing scan of the apparatus is performed (S5: Y), the comparison signal generated by the speed comparison processing unit 5 is input (S6). Then, when the comparison signal is at a low level (the scanning speed is slower than the reference speed) (S7: Y), the control unit 14 sequentially sets the image information stored in the storage unit 16 in synchronization with the electric signal. To the drive unit 17 (S8). At that time, the control unit 1
4 transfers the image information stored in the storage unit 16 to the drive unit 17 for each number of nozzles of the inkjet recording head 45, and also to the drive unit 17 twice for each pixel included in the image information. Therefore, each pixel is printed twice.

On the other hand, when the comparison signal is at a high level in S7 (the scanning speed is faster than the reference speed) (S7: N),
The control unit 14 reads the image information stored in the storage unit 16 for the number of nozzles provided in the inkjet recording head 45 and transfers the image information to the drive unit 17 (S9).

The drive unit 17 drives the ink jet recording head 45 in accordance with the image information transferred by the control unit 14 to print a normal image or a dark and thick image. The above steps S6 to S9 are performed until the printing scan of the apparatus is completed (S10: Y).
Repeated.

FIG. 7 is a schematic diagram showing the results printed in S8 and S9. In the figure, section A is a section scanned at a speed lower than the reference speed, and section B is a section scanned at a speed faster than the reference speed. The print image schematically shows the case where the letter "T" is printed.
In the section A, each pixel is printed twice. On the other hand, in the section B, each pixel is printed once.

Since the image forming apparatus is configured and operates as described above, it is possible to print a thicker and thicker image than in normal printing by merely lowering the scanning speed below a predetermined reference speed.

Further, in this image forming apparatus, the reference speed is set to be equal to or less than half of the maximum driving frequency of the ink jet recording head 45, so that the maximum driving frequency of the ink jet recording head 45 is set even when the pixel is printed twice. Good print results can be easily obtained without interrupting the print scan.

In the present embodiment, the pixels are printed twice, but the number of times may be three or more. When the number of times of printing is increased, the reference speed is the maximum drive frequency of the ink jet recording head 45. Set the speed equal to or less than the speed divided by the number of prints.

Further, in this embodiment, the number of pixels is two.
Although the image is thickened and thickened by printing twice, the image may be thickened and thickened by increasing the amount of ink ejected by the inkjet recording head 45 once.

Next, a modified form in which the reference speed can be changed will be described. That is, the image forming apparatus of this modification is configured to include the reference voltage changing unit 53 that changes the reference voltage in the speed comparison processing unit 50 as shown in FIG.

Therefore, the operator can set the reference speed that suits his or her preference. Of course, the upper limit of the set reference speed does not exceed half of the maximum driving frequency of the inkjet recording head 45.

[0038]

As is apparent from the above description, in the image forming apparatus according to the first aspect of the present invention, the image to be printed can be printed only by making the moving speed slower than the preset reference speed. It can be printed thick or dark.

Further, in the image forming apparatus according to the second aspect of the invention, since the image is printed thick or dark by printing each pixel a plurality of times, a simple structure is required without requiring special image data or the like. The above effect can be achieved.

In the image forming apparatus according to the third aspect, the reference speed is set to be equal to or lower than the speed obtained by dividing the maximum driving speed of the recording means by the number of times of printing, so that the printing speed is the maximum driving speed of the recording means. Therefore, it is possible to always obtain a normal print result without interrupting the print scan.

Further, in the image forming apparatus according to the fourth aspect, the reference speed can be arbitrarily set, so that the operator can perform scanning at a speed suited to his / her preference.

[Brief description of drawings]

FIG. 1 is an external view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an internal configuration diagram of the image forming apparatus.

FIG. 3 is an explanatory diagram for explaining a method of detecting a movement amount and a movement direction of the image forming apparatus.

FIG. 4 is a functional block diagram of the image forming apparatus.

FIG. 5 is an electrical block diagram showing details of a speed comparison processing unit of the image forming apparatus.

FIG. 6 is a flowchart for explaining a print control operation of the image forming apparatus.

FIG. 7 is a schematic diagram showing a printing result by the image forming apparatus.

FIG. 8 is an electrical block diagram showing details of a speed comparison processing unit in an image forming apparatus according to a modified embodiment of the present invention.

[Explanation of symbols]

 5 Speed Comparison Processing Section 11 Encoder 42 Roller 45 Inkjet Recording Head 14 Control Section 50 Speed Comparison Processing Section 53 Reference Voltage Changing Section

Claims (4)

[Claims] 1. A recording means for printing an image on a recording medium, a speed detecting means for detecting a relative moving speed of the recording means and the recording medium, and a movement detected by the speed detecting means. An image forming apparatus including: a control unit that drives a recording unit in synchronization with a speed; a speed comparison unit that compares a moving speed detected by the speed detection unit with a preset reference speed; If the moving speed is judged to be slower than the preset reference speed in the speed comparing means,
An image forming apparatus, characterized in that the image printed by the recording means is controlled to be printed thick or dark. 2. The control means prints each pixel forming the image to be printed a plurality of times when the moving speed is judged to be slower than a preset reference speed by the speed comparing means. The image forming apparatus according to claim 1, which is controlled. 3. The image forming apparatus according to claim 2, wherein the reference speed is set to be equal to or lower than a speed obtained by dividing the maximum driving speed of the recording unit by the number of times of printing. 4. The image forming apparatus according to claim 1, further comprising a reference speed setting unit for arbitrarily setting the reference speed.