JPH01264880A - Detection of front and rear surfaces of recording sheet - Google Patents

Abstract

PURPOSE:To prevent improper insertion of a recording sheet by automatically detecting a front and a rear surfaces of the recording sheet by a method wherein a quantity of reflected light from the front surface and the rear surface of the recording sheet is detected, and the front or rear surface is discriminated based on a difference in the quantity of reflected light from the front and rear surfaces. CONSTITUTION:Sensors 66, 67 detecting states of a front surface and a rear surface of a recording sheet are arranged at required positions on a path of the recording sheet 45, and detection signals 66A, 67A from the sensors are transmitted to a control circuit 53. In the case of a coarse surface of paper or the like, light of intensive directivity irradiated through a slit 73 from a light source 71 is scattered on a surface of the recording sheet 45, and a quantity of reflected light incident upon a light receiving element 72 arranged on the path of the reflected light decreases to a low level of a fraction of irradiation light. In the case of a smooth surface such as a surface of a BPF or the like, the quantity of the reflected light does not decrease less than that of the irradiation light, and is kept at a high level. Thus, a class of, or the front or rear surface of the recording sheet 45 can be detected based on a difference in the quantity of the reflected light between the front surface and the rear surface of the recording sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for identifying the front and back sides of a supplied recording sheet in a recording apparatus such as a printer or facsimile.

[Conventional technology]

Recording sheets (recording media) used in recording devices such as printers and facsimiles may be paper, QUIP (overhead projector) sheets, or BPF (
Bank print film) etc. are used accordingly.

Paper is generally an opaque sheet, and there are slight differences in gloss and ink adsorption depending on the paper quality and front and back sides, but compared to other materials such as plastic film, paper has a rough surface and less gloss.

The OHP sheet is formed by coating one or both sides of a light-transmissive plastic film such as a polyester sheet to form a recording (printing) surface.

The BPF has an ink absorbing layer and an ink transport layer on the back side of a base layer of a transparent plastic film, and a recorded image formed in the ink absorbing layer by ink droplets ejected from the ink transport layer side (back side) is transferred to the base layer. Observation is made through the layer (surface).

This BPF provides image protection and high image quality, and because it records from the back side, printing is performed based on inverted image data obtained by mirror image conversion of image information.

In addition, in recording (printing) mode, recording (printing) is possible from the surface.
In addition to the normal image mode and mirror image mode, there is a BPF mode in which printing is performed on the BPF etc. from the back side, and each mode is adopted in correspondence with one or more types of recording sheets.

[Problem that the invention seeks to solve]

By the way, there are types of recording sheets that allow recording on both the front and back sides in the same way, but the BPF and single-sided coating O
If you do not set the front and back sides of sheets such as HP sheets correctly, they will not be recorded (
If printing is not possible, or if the front and back sides are reversed, a normal image or mirror image may be formed although it is not a regular image.

However, in conventional recording devices, the type of recording sheet and the front and back sides of the recording sheet are generally determined by the user's visual observation or touch, making it difficult to automate the operation of checking the front and back sides. It was time consuming and moreover, there was a high possibility of making the wrong decision.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting the front and back sides of a recording sheet, which can solve the problems of the prior art described above, can automatically determine the front and back sides of a recording sheet, and can improve the reliability of recording operations.

[Means for solving problems]

The present invention uses a light source that irradiates a recording sheet with light and a light receiving element that detects the amount of light.The light receiving element placed at a predetermined position detects the amount of reflected light from the front and back sides of the recording sheet, and The above object is achieved by identifying the front and back sides based on the difference in light amount.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic block diagram of a color inkjet recording apparatus suitable for carrying out the present invention, and FIG. 2 is a block diagram of the control system shown in FIG. 1.

In FIG. 1, a recording sheet 45 pulled out from a continuous roll sheet 40 is conveyed by the rotational frictional force of a feed roller 43 via guide rollers 41 and 42, and is discharged in the direction of an arrow 44. .

A recording section including a recording head unit 49 is arranged in front of the recording sheet 45 between the upper and lower guide rollers 42, 41.

The recording section is provided with a guide shaft 46 arranged parallel to guide rollers 42 and 41, and a head unit 49 for color printing is positioned on a carriage 48 that reciprocates left and right along the guide shaft 46. It is equipped with

The head unit 49 consists of four recording heads, namely a head 49Y with yellow ink color, a head 49M with magenta ink color, a head 49C with cyan ink color, and a head 49Bk with black ink color. Each color ink is supplied from the ink tank.

By moving the carriage 48, each recording head can scan the recording sheet 45 for recording.

The recording head 45 is intermittently fed (line fed) by the printing wheel (height) of each recording head 49, but while the recording sheet 45 is stopped in the feeding direction, the head 49 is scanned in the direction of arrow P. Ink droplets are ejected according to the image signal.

The carriage 48 is a carriage motor (pulse motor) 5
1 through a timing belt 47,
The feed roller 43 is rotationally driven by a sheet feed motor 52.

In FIGS. 1 and 2, a control circuit 53 that controls carriage operation outputs a reader control signal 55 to the reader portion 54, an image processing control signal 57 to the image control circuit 56, Recording head 49Y for each color
.
A sheet feed motor control signal 62 is output to a sheet feed motor driver 61 that drives the sheet feed motor 2.

Image information r for each ink color from the reader part 54
YJ, rMJ, and rcJ are input to the image processing circuit 56, where they are image-processed and then converted into image signals Y, M for each color.
, C, and Bk to the control circuit 53, and the control circuit 53 controls the recording head 49Y of each color based on this image signal.
, 49M, 49C1498 ink ejection control signal 50
Output.

Further, a sensor 6 for detecting the state of the front and back surfaces of the recording sheet 45 is provided at a desired position on the path of the recording sheet 45.
6.67 are arranged, and detection signals 66A and 67A from these sensors are transmitted to the control circuit 53.

The sensors 66 and 67 use a light source that irradiates light onto the recording sheet 45 and a light receiving element that detects the amount of light, and the light receiving element placed at a predetermined position detects the amount of reflected light from the front and back surfaces of the recording sheet. , which can detect the type of recording sheet 45 or the front and back sides based on the value of the amount of reflected light on the front and back sides or the difference therebetween.

In addition, as shown in Figure 2, the printing mode of the recording device, such as printing on plain paper, printing on OHP sheets, BPF printing, or normal image printing or mirror image printing, can be specified using the touch keys, and the signal can be sent to the recording device. An operation panel 70 for sending data to the control circuit 53 is provided.

As the recording sheet 45, paper, OHP sheet, BPF can be used.
There are several types, and the conditions of their front and back sides are as follows.

That is, in the case of paper, both the front and back surfaces are rough, and even if highly directional light is irradiated, the reflected light becomes scattered light on both the front and back surfaces, and the directivity disappears.

In the case of an OHP sheet, both the front and back surfaces have glossy and smooth surfaces, and when irradiated with highly directional light, the reflected light from both the front and back surfaces becomes highly directional light.

In the case of BPF, the front surface is smooth and glossy, but the back surface is rough, so when irradiating highly directional light, the reflected light on the front surface becomes a highly directional ray, but on the back surface it is scattered. It becomes light and its directionality disappears.

FIG. 3 shows an example of a sensor that optically detects rough and smooth surfaces.

Figure 3 (A) shows the case of a rough surface such as paper, and the light source 7
The highly directional light irradiated from 1 through the slit 73 is scattered on the surface of the recording sheet 45, and the amount of reflected light entering the light receiving element 72 arranged on the reflected light path is a fraction of the irradiated light.
decreases to low levels.

FIG. 3(B) shows the case of a smooth surface such as the surface of a BPF.
The light with strong line spacing is reflected on the surface of the recording sheet 45, and the amount of reflected light entering the light receiving element 72 disposed on the reflected optical path is maintained at a high level without decreasing much compared to the irradiated light.

FIG. 3(C) is a graph showing the output voltage of the light receiving element 72. FIG. 3(A) shows a low level L, and FIG. 3(B) shows a high level H.

In this way, by detecting the amount of reflected light, it is possible to identify the condition of the surface of the recording sheet 45, that is, whether it is rough or smooth.

FIG. 4 shows another example of a sensor that optically detects rough and smooth surfaces.

In the case of FIG. 4, the light-receiving element 72 is placed at a position away from the reflected optical path, and a slit 74 is provided in front of the light-receiving element.

(A) in FIG. 4 shows the case of a rough surface such as paper or the back side of a BPF, and the highly directional light emitted from the light source 71 through the slit 73 is scattered on the surface of the recording sheet 45, and the reflected light is evenly distributed. Therefore, a considerable amount of light enters the light-receiving element 72 located outside the reflection optical path, although it is a fraction of the amount of light.

FIG. 4(B) shows the case of a smooth surface such as the surface of BP, F or an OHP sheet, and the highly directional light irradiated from the light source 71 through the slit 73 is on the recording sheet 4.
5, and the reflected light also has strong directivity in the direction of a constant reflection angle, so that almost no light enters the light receiving element 72 located outside the reflected optical path.

FIG. 4(C) is a graph showing the output voltage of the light receiving element 72, and contrary to the case of FIG. 3, the rough surface of FIG. 4(A) has a high level H; The smooth surface of (B) has a low level L.

Therefore, also by the method shown in FIG. 4, it is possible to identify whether the surface of the recording sheet 45 is rough or smooth by detecting the amount of reflected light.

According to the above recording sheet detection means 66 and 67, the type of recording sheet 45, that is, paper, OHP sheet, BP
It is possible to identify which sheet, such as F, is set.

For example, if both the front and back sides are rough, it can be determined that it is paper, if both the front and back sides are smooth, it is an OHP sheet, and if the front side is smooth and the back side is rough, it can be determined that it is BPF.

Note that when the type of recording sheet 45 is determined only by the roughness of one side, such as when distinguishing two types of paper and OHP, or when distinguishing between paper and the surface of BPF, the recording sheet detection means 66 and 67 You can get away with only 11 pieces.

Further, according to the recording sheet detection means 66 and 67, it is also possible to identify the front and back sides of the recording sheet 45.

For example, if the recording sheet 45 used is a BPF, the difference in the amount of reflected light from the front and back surfaces, that is, whether the amount of reflected light is at a high level H or a low level is determined by the detection method shown in FIG. 3 or 4. By detecting this, it is possible to identify whether the front and back sides are correctly set.

Furthermore, a control system as shown in FIGS. 1 and 2 detects the front and back sides of the supplied recording sheet 45, and if the front and back sides are correctly centered, recording is performed, and the front and back sides are set in reverse. In this case, it is possible to implement a control program in which it is determined, depending on the type of the recording sheet 45, whether to disable recording or to enable recording if given another instruction from the user.

By incorporating the control system as described above, it is possible to automatically identify the type of recording sheet 45 or the front and back sides of the recording sheet 45, and it has become possible to eliminate malfunctions during recording.

Furthermore, depending on the recording (printing) mode such as normal image printing, tJtl printing, BPF printing, etc., it can be divided into cases where it is possible to record (print) even if the front and back are reversed, and cases where printing is absolutely impossible. According to the above control system, the sensor 6
6. Based on the detection signal from 67, it is possible to determine if printing is possible although it is not legal, and in that case, a message to that effect is displayed and control is made to enable printing after waiting for another instruction from the user. , as well as preventing malfunctions during recording.
It becomes possible to improve the functionality by expanding the range of recording sheets that can be adopted.

In FIG. 5, a light source 71 and a light receiving element 72 are arranged on both sides of a recording sheet 45, and the recording sheet 45 is
FIG. 5 is a schematic diagram showing a method for identifying types of No. 5;

(A) in FIG. 5 shows a case in which the amount of transmitted light is small due to an opaque material such as paper, and (B) in FIG. 5 shows a case in which the amount of transmitted light is large in a transparent or translucent material such as a BPF or OHP sheet.

FIG. 5 (C) is a graph showing the level of the output voltage of the light receiving element. When the paper is opaque like the paper shown in FIG. 5 (A), the amount of transmitted light is small and the output voltage of the light receiving element 72 is at a low level. In the case of the OHP sheet or BPF shown in FIG. 5(B), the amount of transmitted light is large, and the output voltage of the light receiving element 72 becomes a high level H.

Furthermore, by using the control system and optical detection means described above with reference to FIGS. 1 to 5, the following recording apparatus can be constructed.

First, record sheet 4 such as paper, OHP sheet, BPF, etc.
5, and by detecting the condition (smoothness) of the front and back surfaces of the supplied recording sheet 45, the type of recording sheet 450 and the front and back sides are determined, and the recording is normal for the set recording mode. If it is a sheet, record it,
A recording sheet specification type recording device is provided, which is configured to perform recording upon a second instruction from the user if an image can be formed on an irregular recording sheet for the set recording (printing) mode. Ru.

Another configuration is to detect recording modes such as normal image, mirror image, and BPF type, and to detect front and back sides, and to perform recording if the recording sheet is a regular recording sheet for the specified recording mode, and even if it is an irregular recording sheet. If image formation is possible, a recording (printing) mode designation type recording device is provided that is configured to issue a message and record the message if the user gives another instruction.

FIG. 6 is a flowchart of the operation of the recording sheet specification type recording apparatus, and FIG. 7 is a flowchart of the operation of the printing mode 1 fixed type recording apparatus.

In FIG. 6, when there is a recording command, an initialization process is performed in which the flags of each sensor 66, 67 are set to 0 and each display is stopped in step 101, and the presence or absence of the recording sheet 45 is determined in step 102, and the recording is performed. If there is no sheet, the sheet will be hidden.

If there is a recording sheet 45, the sheet non-display is stopped in step 103, and in step 104, a surface detection sensor (detection means) 66 detects the smoothness of the surface of the recording sheet 45 based on the amount of reflected light.

If the sensor 66 detects that the surface is rough, step 10
5, the recording sheet 4 is detected by the sensor 67 for detecting the back side.
The smoothness of the back surface of No. 5 is detected by the amount of reflected light.

If the sensor 67 determines that the back side is rough, it can be determined that a recording sheet (paper) that is rough on both the front and back sides is inserted, and the process proceeds to step 106, where the recording (printing) mode of the recording device is set to BPF type. Determine whether or not the

If the BPF recording mode is set, paper that is rough on both sides is not a regular recording sheet (BPF), so
In step 107, a sheet error display is displayed, and in step 1
Display a question (message) at 08.

At this time, the message may be, for example, ``Please select either the correct sheet or the correct print mode, or the image color may change slightly, but the image can be formed and should be recorded.'' indicate.

The user issues another instruction as to whether or not to record at step 109, and if "not to record", the question display is stopped at step 110 and the process returns to step 7, step 102.

If the instruction in step 109 is "record", the process advances to step 111 to stop displaying the question, and then in step 112 a recording process is performed in the BPF type recording (printing) mode.

If it is determined in step 106 that the mode is not the BPF type recording mode, the process proceeds to step 113, where it is determined whether the ○HP recording mode is set, that is, the recording mode that uses an OHP sheet, and whether or not the OHP recording mode is set. If it is determined that there is, the error display is stopped in step 114, and then, in step 115, recording is performed in an OHP recording (printing) mode in which image formation is possible, although it is not regular.

If it is determined in step 113 that the OHP printing mode is not set, it is determined that the normal recording (printing) mode is set, in which the remaining plain paper is used as the regular sheet, and an error occurs in step 116. After the display is stopped, in step 117, normal image recording processing is performed on plain paper in the normal printing mode.

If the back surface is determined to be smooth by the sensor 67 in step 105, this means that the sheet has a rough surface and a smooth back surface, and the BPF is inserted face down (with the front and back reversed). Therefore, image formation is impossible, and after setting a flag on the back sensor 67 in step 118, the process proceeds to step 119 to display a sheet error, and the process proceeds to step 110 described above without recording. Stop the question display (mensage) and proceed to step 102
Return to

Further, if the front surface is determined to be smooth in step 104, a flag is set on the front surface sensor 66 in step 120, and in step 121, the sensor 67 determines whether the back surface is smooth or rough.

If the sensor 67 determines that the printing sheet is rough, it can be determined that a printing sheet (BPF) with a smooth surface and a rough back surface is inserted, and in step 122, it is determined whether the printing mode is set to the BPF type mode or not. If it is determined and set to BPF type mode, it means that a regular recording sheet has been set, and the process proceeds to step 111 described above and asks the question (
(message) display is stopped, and recording processing is performed in the BPF print mode in step 112.

If it is determined in step 122 that it is not the BPF printing mode, it means that BPF has been inserted by mistake, and the process proceeds to step 123 where a sheet error is displayed and step 1
Display the question (message display) at step 24, and step 12
In step 5, the user instructs whether or not to record by operating the touch key again.

If not to record, proceed to step 110 described above and simply stop displaying the question, then return to step 102 and repeat the above operation.

When there is an instruction to record in step 125, error question display is stopped in step 126, and step 12
Proceeding to step 7, it is determined whether the OHP print mode is specified.

If OHP printing mode is selected, step 114 described above is performed.
After proceeding to step 115 to stop error display, recording processing is performed in an OHP printing mode in which image formation is possible although not regular.

On the other hand, if it is determined in step 127 that the mode is not OHP printing mode, the process proceeds to step 116 described above to stop error display, and then in step 117, the remaining recording (printing) mode, which is not regular but allows image formation, is selected. Recording processing is performed in normal image mode on plain paper.

If it is determined in step 121 that the back side is also smooth, the process proceeds to step 128 where the flag of the back side sensor 67 is set, and then in step 129 the printing mode is changed to BPF.
Determine whether it is an expression or not.

The recording sheet in this case, which is smooth on both the front and back, is an OHP sheet, so if it is in BPF printing mode, it may be accidentally omitted.
The HP sheet has been inserted, and step 130
After displaying a sheet error in step 131 and displaying a question (message) in step 131, the user again instructs in step 132 whether or not to execute recording in an unauthorized but image forming mode.

If there is an instruction to execute, the process advances to step 111 to stop displaying the question (message), and then, in step 112, recording processing is performed in the BPF print mode.

On the other hand, if there is an instruction not to perform recording in step 132, the process advances to step 110, where the question display is simply stopped, and then the process returns to step 102, where the above-mentioned operations are repeated.

In step 129 described above, the set print mode is set to BPF.
If it is determined that it is not a formula, the process advances to step 133 and the OH
It is determined whether or not it is in the P print mode.

If it is OHP printing mode, this means that a regular sheet has been inserted as the recording sheet 45, and step 114
After proceeding to step 115 to stop the error display, press O in step 115.
Record in HP print mode.

On the other hand, if it is determined in step 133 that the OHP printing mode is not selected, in this case, it generally means that the printing mode for plain paper is set, so the process proceeds to step 116 described above to stop the error display, and then step In step 117, recording processing is performed in the normal image printing mode on plain paper.

By the operation procedure explained above with reference to FIG. 6, paper, O
The recording processing operation in a type of recording apparatus that specifies recording sheets such as HP sheets and BPF sheets is controlled.

Next, the recording processing operation of the aforementioned recording (printing) mode designated type recording apparatus will be explained with reference to FIG.

The operating procedure in Fig. 7 is different from the flowchart in Fig. 6 described above.In steps 113, 127, and 133 in Fig. 6, it is determined whether or not the recording (printing) mode using an OHP sheet is specified. On the other hand, steps 113, 127, and 133 corresponding to these in FIG. The operations are substantially the same in all cases.

Note that the present invention applies to inkjet recording devices as well as
The present invention can be similarly applied to recording apparatuses of other types such as thermal type and wire dot type.

〔Effect of the invention〕

As is clear from the above description, according to the method for detecting both sides of a recording sheet of the present invention, a light source that irradiates the recording sheet with light and a light receiving element that detects the amount of light are used, and the light receiving element placed at a predetermined position performs recording. The amount of light reflected from the front and back sides of the sheet is detected and the front and back sides are identified based on the difference in the amount of light reflected from the front and back sides.This automatically and accurately detects the front and back sides of the recording sheet to prevent unauthorized insertion of the recording sheet. A method for detecting the front and back sides of a recording sheet that can eliminate malfunctions during recording processing is obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the configuration of a color inkjet recording apparatus suitable for carrying out the present invention, and FIG.
3 is a schematic diagram of the optical detection means for detecting the smoothness of the recording sheet; FIG. 4 is a schematic diagram showing another example of the optical detection means for the smoothness of the recording means. 5 is a schematic diagram of the light transmission amount detection means of the recording means, FIG. 6 is a flowchart of the recording processing operation of the recording device of FIG. 1, and FIG. 7 is another recording processing of the recording device of FIG. 1. It is a flowchart of operation. 45-------Recording sheet, 48--...
--- Carriage, 49--- Head unit, 49Y, 49M, 49C149Bk, ----
--1 recording head, 5 (1-----recording head control signal, 53-----1.-control circuit, 56--
...--Image processing circuit, 66----------Surface detection means (sensor), 67--
−Detection means (sensor) on the back side, 70−・−・−・・・
Operation panel, 71-・-----One light source, 72-・
・−1−−−−−Photodetector.

Claims (1)

[Claims] (1) Using a light source that irradiates the recording sheet with light and a light receiving element that detects the amount of light, the light receiving element placed at a predetermined position detects the amount of reflected light from the front and back sides of the recording sheet, and the amount of reflected light from the front and back is detected. A method for detecting the front and back sides of a recording sheet, characterized by identifying the front and back sides based on the difference between the two sides.