Wrong checked checkbox Angularjs

I have a problem with a template with AngularJS. The page shows a books list with a checkbox. This is used for batch actions, like delete the books. If the list is too long, the books will be shown in a paged list

The problem is, if I check some of them and change the page number, the checkbox will be checked in the same position. Is easier to understan with this screenshots

• I check the first and the third result: http://ift.tt/2xMvXo6

• Click on the next page: http://ift.tt/2ftS5cr

Distinct pages and results, same checked checkbox

The get this results I´m using a query in a action.class.php and sending the json like this:

$ejemplares = array();
foreach($data as $ejemplar_bd)
{
    $id_documento = $ejemplar_bd['id_registro'];

    $ejemplar = array();
    $ejemplar['id'] = $ejemplar_bd['id'];
    $ejemplar['idDoc'] = (int)$ejemplar_bd['id_registro'];
    $ejemplar['numregistro'] = (int)$ejemplar_bd['numregistro'];
    $ejemplar['codigo'] = $ejemplar_bd['codigoejemplar'];
    $ejemplar['estado'] = $ejemplar_bd['estado'];
    $ejemplar['signatura'] = $ejemplar_bd['signatura1']."-".$ejemplar_bd['signatura2']."-".$ejemplar_bd['signatura3'];
    $ejemplar['tipo'] =$ejemplar_bd['tipoejemplar'];
    $ejemplar['reservas']=$ejemplar_bd['reservas'];
    $ejemplar['Ubicacion']=$ubicaciones[$ejemplar_bd['id']];
    $ejemplar['Motivo']=$ejemplar_bd['motivo_expurgado'];
    $ejemplar['Editorial']=$data_editorial['valor'];
    $ejemplar['Imprimido']= $ejemplar_bd['imprimido'];
    $ejemplar = array_merge($ejemplar,$fondos[$id_documento][$ejemplar['id']]);

    $ejemplares[] = $ejemplar;

}

$this->json_data = json_encode($ejemplares);

After that, the code in the template is:

<tr ng-repeat="item in data| filter:Buscar | filtroNumregistro:numregistro | filtroCodEjemplar:codEjemplar | filtroNombreNormalizado:nombreFiltro  | orderBy:sort:reverse | limitTo: (currentPage - 1) * pageSize - filtrados.length | limitTo: pageSize track by $index">
        <td class="sf_admin_text sf_admin_list_td_nombre">
          <input type="checkbox" name="ids[]" value="" class="sf_admin_batch_checkbox">
        </td>
        <td class="sf_admin_text">
          
        </td>
        <td class="sf_admin_text">
          
        </td>
        <td class="sf_admin_text sf_admin_list_td_titulo">
            <span><a ng-href=""></a></span><br/>
            <span class="autorListEjemplar" ng-repeat="autor in item.Autor"></span>
        </td>
        <td class="sf_admin_text" style="width:10%;">
          
        </td>
        <td class="sf_admin_text" style="width:10%;">
          
        </td>
        <td class="sf_admin_text" style="width:10%;">
          
        </td>
        <td class="sf_admin_text" style="width:10%;">
          
        </td>
        <td class="sf_admin_text">
          
        </td>
      </tr> etc...

What is going on? What could be the problem?

Thanks in advance