WO2015030785A1

WO2015030785A1 - Printer with an internal scanner

Info

Publication number: WO2015030785A1
Application number: PCT/US2013/057433
Authority: WO
Inventors: Gerald A. LARSON
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2013-08-30
Filing date: 2013-08-30
Publication date: 2015-03-05

Abstract

A printer is disclosed. The printer includes a scanner in the paper path between the print engine and the output tray. The scanner scans test areas on recently printed pages. The printer compares the image quality in the test area with the image quality from a reference area. When the image quality in the test area has degraded below a threshold amount compared to the image quality of the reference area, a toner low warning is displayed.

Description

Printer with an internal scanner

BACKGROUND

[0001] Laser printers use toner to create images on the page. The toner typically comes in replaceable toner cartridges. When the toner in one toner cartridge runs out, the user swaps out the empty toner cartridge with a new toner cartridge. The new toner cartridge supplies the printer with more toner so that the user can continue printing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 is a mechanical sectional side view of an example printer 100.

[0003] FIG. 2 is an example electrical block diagram of a printer.

[0004] FIG. 3 is an example block diagram of the processor 202 coupled to memory 204.

[0005] FIG. 4 is an example flow chart for determining when the toner cartridge is low on toner.

[0006] FIG. 5 is an example test page 500 printed with a toner cartridge that was low on toner.

DETAILED DESCRIPTION

[0007] When a toner cartridge runs out of toner the printer can no longer create images on a page. Toner is the marking material used by laser printers to create images on the page. Toner is typically a black powdery substance that can be melted by the printer and fused to the page. Even though most toner cartridges have an agitator to evenly spread the toner across the toner cartridges, most toner cartridges will still run out of toner in one section of the toner cartridge before the other sections of the toner cartridge run out of toner. The section of the toner cartridge that empties first will start to create light or blank areas in the images printed on the page before mere is degradation of the image quality in the other areas of the page. The area on the page that corresponds to the section of the toner cartridge that runs out of toner first is known as the depletion region. Multiple toner cartridges of the same type will typically end up with the depletion region in the same location on die page. Printing a page that contains light or blank areas may make the page unusable and therefore wastes paper. In addition the user may have to reprint the page after replacing the toner cartridge. Therefore most printers try to warn the user that the toner is running out so the user has a chance to replace the toner cartridge before a page is printed with blank areas.

[0008] Determining when the toner is about to run out is difficult. One way a printer tries to determining when the toner is low is to use a toner level sensor in the toner cartridge. Unfortunately toner level sensors are not very accurate. A typical toner level sensor is only accurate to within about +3% to -1%. Because of the inaccuracy, the printer typically warns the user to replace the toner cartridge when mere is still some usable life left in the toner cartridge. This wastes toner when the user replaces the toner cartridge before it is empty. Detecting and warning the user just before the toner runs out prevents printing pages with blank spots and makes the best use of the toner in a toner cartridge.

[0009] When the toner in a toner cartridge is starting to run low, the image quality of the printed output from the printer begins to degrade. Printed output may include both the printed text and printed images on the page. The image quality typically degrades unevenly across the page with the degradation first appearing in a depletion region. In one example the depletion region is in a column down the left side of the page near the left edge of the page. The depletion region for a given toner cartridge can be determined by counting the number of pixels printed in different sections of the toner cartridge. The section that has printed the most pixels will contain the depletion region. In one example a printer will use an internal scanner to measure the image quality of the printed output. The scanner is located after or downstream from the print engine in the paper path of the printer. Because the scanner is located in the paper path after the print engine, all pages printed by the printer can be scanned.

[0010] In one example, every page printed by the printer will be scanned. In other examples, only a selected number of pages will be scanned, for example every 5^th, page, every 10^th page, every 50* page, or the like. A test area and a reference area from the scanned pages will be evaluated to determine when the printer is running low on toner. [0011] In one example the reference area will be from a page printed when the toner cartridge was new/full. The test area will be from the depletion region on a recently printed page. In another example, both the test area and the reference area will be from different locations on the same, recently printed, page.

[0012] When the reference area is from a page printed when the toner cartridge was new/full, the printer will scan an image of a page shortly after the toner cartridge is first installed. The printer will determine the image quality of the reference area and save this information in non-volatile memory. During the life of the toner cartridge the printer will scan pages as they are printed. The printer will determine the image quality of a test area from these recently printed pages. The printer will compare the image quality of the test area with the image quality of the reference area. When the printer detects that the image quality of a test area has degraded beyond a threshold compared to the image quality of the reference area, the printer will warn the user that the toner cartridge is almost out of toner and should be replaced.

[0013] When the reference area and the test area are both areas from the same recently printed page, the test area will be from the depletion region and the reference area will be from a different, non-overlapping area on the page. The printer will compare the image quality of the test area with the image quality of the reference area. When the printer detects that the image quality of the test area has degraded beyond a threshold compared to the image quality of the reference area, the printer will warn the user that the toner cartridge is almost out of toner and should be replaced. In one example the depletion region is in a column down the left side of the page near the left edge of the page.

[0014] In one example the scanner may not scan the full width, the full length or either the full width or length of the page. In some examples the scanner will only scan the width needed for the test or reference area. In some examples the scanner will only scan the length needed for the test or reference area. When the reference area is scanned from a different page than the test area, the scans for both the reference area and test area can be the same width and located in the same fairly narrow column of the page (i.e. the depletion region). The depletion region typically starts out narrow and increases in width down the length of the page. The depletion region is typically between .5 inches and 2 inches wide (12.7 - 50.8 mm). When the reference area and the test area are scanned from the same page, the scanned area is wider than the depletion region. The length of the scan for the test and reference areas can be between 1 inch and the length of the page.

[0015] Figure 1 is a mechanical sectional side view of an example printer 100.

Printer 100 comprises an input tray 102, an output tray 104, a pick roller 106, a pair of pinch rollers 108, a print engine 110, a toner cartridge 112, a transfer roller 114, a fuser 116, a pressure roller 118 and an internal scanner 120. Input tray 102 contains a stack of blank pages 124. The blank pages are moved, one page at a time, from the input tray 102 along a paper path to the output tray 104. The paper path runs from the input tray 102, between the pair of pinch rollers 108, between the print engine 110 and the transfer roller 114, between the fuser 116 and pressure roller 118, past the scanner, and into the output tray 104. The pick roller moves the top sheet 126 from the stack of pages 124 towards the pinch rollers 108. Page 126 is shown after it has been moved off the top of stack 124.

[0016] Print engine 110 rotates in the direction shown by the arrow. As the print engine rotates, toner from the toner cartridge 112 is deposited onto print engine 110 to form an image. In this example the toner cartridge 112 and the print engine 110 are shown as two separate parts. In other examples the toner cartridge 112 and print engine 110 are integrated into one unit. As a page passes between print engine 110 and transfer roller 114, the toner is transferred from the print engine 112 onto the top side of the page, forming the image on the page. The fuser 116 is heated to a predetermined temperature. As a page with toner on its top surface passes between the fuser 116 and the pressure roller 118, the toner is partially melted and fused to the page. As the page passes by the internal scanner 120 an image of the page can be scanned. The page is then deposited into the output tray 104. Page 122 is shown passing by the internal scanner 120 as it moves towards the output tray 104.

[0017] In one example, internal scanner 120 is sized to be able to scan the full width of each page as it passes by in the paper path. In other examples, the scanner width may not be as wide as the page, for example the scanner may be ½ or ¼ the width of the maximum page width, or may be just wide enough to scan the depletion region on a page. When the scanner is smaller than the page width, the scanner may be positioned to scan the left half, the left quarter, or the depletion region of the page. Internal scanner 120 may be a folded optical path scanner or a contact image sensor scanner. In this example, internal scanner 120 is shown in the paper path after the fuser 116. In other examples the scanner may be positioned after the print engine 110, but before the fuser 116.

[0018] Figure 2 is an example electrical block diagram of a printer. Printer comprises a processor 202, memory 204, input/output (I/O) module 206, print engine 208, formatter 210, display 216 and an internal scanner 214 all coupled together on bus 212. In some examples printer may also have a user interface module, an input device, and the like, but these items are not shown for clarity. Processor 202 may comprise a central processing unit (CPU), a micro-processor, an application specific integrated circuit (ASIC), or a combination of these devices. Memory 204 may comprise volatile memory, non-volatile memory, and a storage device. Memory 204 is a non-transitory computer readable medium. Examples of non-volatile memory include, but are not limited to, electrically erasable programmable read only memory (EEPROM) and read only memory (ROM). Examples of volatile memory include, but are not limited to, static random access memory (SRAM), and dynamic random access memory (DRAM). Examples of storage devices include, but are not limited to, hard disk drives, compact disc drives, digital versatile disc drives, optical drives, and flash memory devices.

[0019] I/O module 206 is used to couple printer to other devices, for example the Internet or a computer. Printer has computer executable code, typically called firmware, stored in the memory 204. The firmware is stored as computer readable instructions in the non-transitory computer readable medium (i.e. the memory 204). Processor 202 generally retrieves and executes the instructions stored in the non- transitory computer-readable medium to operate the printer and to execute functions. In one example, processor executes code that determines when the toner cartridge is low on toner.

[0020] Figure 3 is an example block diagram of the processor 202 coupled to memory 204. Memory 204 contains firmware 320. Firmware 320 contains a check toner module 324. The processor 202 executes the code in check toner module 324 to determine when the toner cartridge is low on toner.

[0021] Figure 4 is an example flow chart for determining when the toner cartridge is low on toner. At 440 a reference area is scanned using the internal scanner. A test area is scanned from a recently printed page using the internal scanner at 442. A recently printed page is a page in the printer paper path downstream from the print engine. The print quality of the test area is compared to the print quality of the reference area at 444. When the print quality of the test area has degraded beyond a threshold compared to the print quality of the reference area a toner low warning is displayed at 446. In one example the display is located on the printer, m other examples the display is remote from the printer, for example the display on a computer, laptop, tablet or phone. When the print quality of the test area has not degraded beyond a threshold compared to the print quality of the reference area, flow returns to 440.

[0022] In one example, the reference area is from a page printed when the toner cartridge is new/full. Because the toner cartridge is full/new, the reference area can be located anywhere on the page. Typically the references area will be in the depletion region. The print quality in the reference area will be measured and stored in non-volatile memory. This method may be able to use a scanner with a smaller width, but it does require some space in non-volatile memory. The test area will be scanned in the depletion region of a recently printed page. A recently printed page is a page in the printer paper path, after the print engine. In some examples the printer has a sensor to detect when a toner cartridge has been installed into the printer. In this case the reference area will be scanned shortly after a toner cartridge has been installed into the printer, for example within 300 pages from when the toner cartridge was installed.

[0023] Most toner cartridge have memory that tracks the number of pages printed by the toner cartridge. In another example, when a printer detects that a toner cartridge has been inserted, the printer will determine if this is a new toner cartridge by reading the number of pages printed by this toner cartridge. If this is a new toner cartridge (i.e. less than 300 pages printed) the printer will scan the reference area from a page printed shortly after the toner cartridge has been installed. If the toner cartridge is not new, for example when a user re-installs the same toner cartridge, the printer will retain the current quality measure of the previously scanned reference area.

[0024] In some examples, the reference area will be scanned from a page sent by a user to be printed. In other examples a test page may be printed by the printer as part of the printer initialization. The reference area will be scanned from the test page printed during the printer initialization. The print quality in the reference area will be measured and stored in non-volatile memory.

[0025] Figure 5 is an example test page 500 printed with a toner cartridge that was low on toner. This test page is an example to show the effects of low toner, and would not be used to scan and save a reference area from the depletion region of the page. Test page 500 comprises a number of different regions: a number of normal text regions 550, four comer target 556, four angled text lines 552 running along the edges of the page, a line art region 558, and a variable density region 554.

[0026] The depletion region for the type of toner cartridge used to print test page 500 is a vertical column 560 near the left edge of the page. The depletion region overlaps with the bottom left comer target 556. Variations in darkness can be seen on the bottom left comer target 556 where it overlaps with the depletion region. In addition, the thickness/darkness of the text 550 in the depletion region has been reduced. The letter "m" 560 in the word "Nam" is located within the depletion region 560. The letter "m" 562 in the word "velillum" is not located within the depletion region 560. The vertical potion of the "m" 560 in "Nam" is between 20% - 30% thinner than the vertical portion of the "m" 562 in "velillum" in the same line of text. This is a clear indication that the toner cartridge used to print this page was low on toner.

[0027] In another example, the reference area and the test area are both areas from the same recently printed page. With this method the image quality of the reference area does not need to be saved away in non-volatile memory. This method may require a wider scanner. The test area will be located in the depletion region of the page. The reference area will be from an area of the page that does not overlap with the depletion area. When the depletion region forms a column along the left side of the page, the reference area will be located in the middle or right side of the page. Typically the test area and the reference area will be aligned horizontally on the page to reduce the size of the image scanned.

[0028] The image quality of the test area of a page just printed will be compared to the image quality of a reference area, independent of when the reference area was scanned. The image quality can be compared using one or more of the following criteria: the thickness of characters in the printed text, the density of a given image area, the width of a line and the like. When the image quality degrades beyond a threshold amount, the printer will warn the user that the toner is running low and the toner cartridge should be replaced.

[0029] In one example the threshold amount is between 8% and 15%. For example, if the thickness of a line in a given letter in the test area is 12% thinner than the same line in the same letter in the reference area, the toner low warning will be given.

[0030] The image quality of the printed output is a measure of different parameters of the objects printed. The image quality includes the thickness of characters in the printed text, the density of a given image area, the width of a line, and the like. In one example, the printer can use optical character recognition (OCR), pattern recognition, or both on the text printed in both the reference area and the test area to select one or more common characters or letters. The letters or character can be selected such that they were printed using the same font, and printed at the same size. The width or thickness of lines forming the common character or letter can be compared between the reference area and the test area.

[0031] In another example, the printer will select the objects to measure using the data in the formatter. Print data is sent to the formatter to be formatted and sent to the print engine. The formatted data is typical a binary stream of data sent to the print engine to either print a pixel or leave it blank. The print data sent to the formatter is higher level data and typically contains text, font and size data for the text, images, line art, location information for the different data types, and the like. The printer can select elements from the print data, for example a letter printed with a given font at a given size, a line of a given width, or an image of a given density, and measure these elements on the printed page. The printer can then use the measured information as the print quality for the page.

[0032] The printer described above is a standalone printer. However, the printer can also be integrated into a multi-functional peripheral (MFP). An MFP typically contains a printer and a scanner integrated into one unit. The printer and scanner can be used individually to print or to scan pages and can be used together to copy pages. The scanner in the MFP is not located in the paper path of the printer and cannot scan pages printed by the printer without a user removing the page from the output tray of the printer and feeding it into the input tray of the scanner. Therefore a scanner that is not located in the print path of the printer is not defined as an internal scanner. MFP's are also known as All-in-One (AiO) devices and multi-functional devices (MFD).

Claims

[0033] CLAIMS What is claimed is:

1. A printer, comprising:

a print engine to print images onto a page using toner, the toner located in a toner cartridge;

a paper path running from an input tray, past the print engine to an output tray; an internal scanner located in the print path between the print engine and the output tray, the scanner to scan an image of a current page traveling through the paper path after passing through the print engine;

a processor coupled to the print engine, the scanner and to a memory, the processor to compare the image quality of a test area in the image of the current page to the image quality of a reference area, the processor to output a toner low warning when the image quality in the test area has degraded below a threshold amount compared to the image quality of the reference area.

2. The printer of claim 1 , wherein the scanner scans the reference area from a page printed shortly after a toner cartridge is installed.

3. The printer of claim 2, wherein shortly after the toner cartridge is installed comprises a page printed within the first 300 pages printed after the toner cartridge is installed in the printer.

4. The printer of claim 1 , wherein the test area is from a depletion region of the image from the current page and the reference area is a different, non-overlapping area of the image of the current page.

5. The printer of claim 1 , wherein the threshold amount is between 5% and 15%.

6. The printer of claim 1 , wherein the threshold amount is based on one or more of the following: a change in a line width, a change in density, and a change in a thickness of at least one character.

7. The printer of claim 1 , wherein the scanner only scans a portion of the current page.

8. The printer of claim 1 , further comprising:

a formatter to format mcoming print data for the print engine, the formatter coupled to the processor; and

wherein elements printed on the current page, in the test area, to be tested for image quality are selected using the print data from the formatter.

9. The printer of claim 1 , wherein elements printed on the current page, in the test area, to be tested for image quality are selected using optical character recognition (OCR).

10. The printer of claim 1 , wherein the printer is a component in a multi- functional peripheral (MFP).

11. A method printing, comprising:

scanning an image of a test area on a page in the paper path of a printer using an internal scanner,

comparing the image quality of the test area to the image quality of a reference area;

outputting a toner low warning when the image quality in the test area has degraded below a threshold amount compared to the image quality of the reference area.

12. The method of claim 11, wherein the reference area is scanned from a page printed shortly after a toner cartridge is installed.

13. The method of claim 11, wherein the test area is from a depletion region of the image from the page and the reference area is a different, non-overlapping area of the image of the page.

14. The method of claim 11 , wherein elements printed on the current page, in the test area, to be tested for image quality are selected using optical character recognition (OCR).

15. A non-transitory computer readable medium containing computer executable instructions, that when executed by a processor in a printer, performs the following method, comprising:

scanning an image of a test area on a page in the output paper path of a printer using an internal scanner;

displaying a toner low warning on a display when the image quality in the test area has degraded below a threshold amount compared to the image quality of the reference area.